PREFACE
The Mothball Manual is a source for information for mothballing buildings and equipment in Saudi Aramco. The manual was compiled from information furnished from Saudi Aramco's technical personnel and input from U.S. Company experts. It is meant to be a guideline for mothballing equipment and facilities and as such does not give specific directions for each piece of equipment. Additional information including a chapter on instrumentation will be furnished as it becomes available. In this way it is hoped this manual can be kept up to date and therefore be of maximum use. If you require further information or assistance regarding this manual, please contact Roger Sarathy at 875-3520.
I.F. AL-ADEL, Coordinator Corrosion Control Division Consulting Services Dept.
Signed _______________________
AER 2365 TSI 51-156
SAUDI ARAMCO MOTHBALL MANUAL
FOR OILFIELD PRODUCTION PROCESSING AND REFINING EQUIPMENT
I
INTRODUCTION
4
II
PHILOSOPHY OF MOTHBALLING
5
III
CORROSION OF MOTHBALLED EQUIPMENT AND PIPELINES
9
IV
PLANNING OF MOTHBALL PROCEDURES
13
V
PROTECTIVE MATERIALS FOR MOTHBALLING
15
VI
GUIDELINES FOR MOTHBALLING OF SPECIFIC EQUIPMENT AND FACILITIES
22
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. VII
WELLS PIPELINES VALVES PRESSURE VESSELS TANKAGE HEAT EXCHANGER EQUIPMENT ROTATING EQUIPMENT ELECTRIC EQUIPMENT AIR CONDITIONING SYSTEMS FLARE SYSTEMS BOILERS AND FIRED HEATERS BUILDINGS
MONITORING AND MAINTENANCE DURING MOTHBALLING
22 26 39 43 49 56 62 82 92 94 96 102 106
VIII
APPENDIX
107
A.
Extracts from Exxon Refinery Mothballing Guide for Saudi Aramco.
108
B.
Recommended mothballing materials in SAMS.
119
C.
Product Information
120
Boiler Lay-up Procedures - Refer to GI-403.001 1
121
TSI 51-156 SAUDI ARAMCO MOTHBALL MANUAL CHAPTER I
INTRODUCTION This manual provides basic guidelines and recommendations for the preparation of detailed procedures for mothballing buildings, oilfield production, processing, and refining equipment. Due to long range forecasts for crude production In-Kingdom, some buildings, operating plants and pipeline systems are being considered for mothballing for a period of 3 - 10 years. Various plants and facilities have already been mothballed for 2 1/2 years and may remain mothballed for an additional 5 to 10 years. Saudi Aramco's recent investigation of mothballed facilities, plants and pipeline systems have indicated various mothballing procedures have given satisfactory results, whereas others are considered unsatisfactory. The basic guidelines and recommendations in this manual are not mandatory. They are based on the experience gained over the last few years in mothballing buildings, oilfield production and processing equipment in Saudi Arabia and the US Companies. The manual has been reviewed by Technical Specialists of Saudi Aramco and each of the U.S. Companies.
CHAPTER II PHILOSOPHY OF MOTHBALLING
OBJECTIVES The need for mothballing occurs when the operation of a plant or facility is not currently needed to achieve Saudi Aramco's objectives. Quite often, the plant and/or equipment that is involved is very costly in terms of capital investment or replacement value. It is in Saudi Aramco's interest to put the equipment in such state that it can be maintained in good condition at a minimum cost. When operational requirements dictate the return of the facilities and the equipment to active service, it is desirable to accomplish this with minimum cost, time and effort. Therefore, the objectives of mothballing can be stated as follows: 1
Preservation of the buildings and equipment without a significant loss of useful operating life and without excessive costs.
2.
The continuation of the preservation state with a minimum of maintenance attention.
3.
Recommissioning with a minimum cost and delay.
The protection of shutdown equipment is always a compromise between cost of preservation, effectiveness in preventing deterioration and the ease with which the plant can be reactivated. Selecting the optimum mothballing procedure requires an economic evaluation of alternatives. The length of shutdown anticipated is important to this evaluation. The expected recommissioning time, however, is the most significant factor. The value of the equipment involved and the cost of maintenance are also necessary for a complete determination of the economics. The following definitions are used in this manual for mothballing equipment for different periods of downtime.
Short Term Mothball Long Term Mothball Minimum first cost Mothball
Downtime
Start-up Time
1/2 - 3 years Over 3 years Over 5 years
Less than 3 months 6 to 12 months 1 to 2 years
TABLE 1, General Categories for Mothballing - page 7, provides a comparison of basic differences between short term, long term and minimum first cost mothballing. The above definitions are not applicable for mothballing buildings. Refer to Chapter VI section 12 which addresses building preservation.
Factors Influencing Mothballing Procedures The following factors have an important influence on the choice of mothballing procedures for a certain piece of equipment or a facility: 1.
Recommissioning Time Time available for recommissioning is the significant factor in selecting a mothballing procedure. Equipment disassembly and remote storage may reduce deterioration but significantly increase startup cost and duration. Using a hydrocarbon for a mothballing medium may also increase start-up time when internal inspection and/or hydrotesting is required prior to start-up.
2.
Length of Shutdown Facilities which will be idle less than six months require little more than the normal turnaround precautions. Such short-term layup is not covered in this Mothball Manual. Mothballing for more than six months requires more preparation and observance of specific precautions (minimum first cost mothballing is an exception).
3.
Climate Equipment can deteriorate rapidly in warm, humid climates while corrosion is less in dry environments. Sea coast locations vary in corrosivity, depending on temperature, humidity and prevailing winds. Saudi Arabia has a variety of climates. The southern area, in general, has a relatively dry climate and equipment in this area is subject to less external corrosion than equipment located in the more humid Northern area and in offshore fields. On the other hand, equipment and facilities located in the Southern area suffer more from the effects of sand than equipment and facilities located in the Northern area.
4.
Nature of Product Internal protection needed for pipeline systems and pressure vessels varies with the nature of the product. Mothballing pipelines used for dry sweet gas or dry crude is less costly and less complicated than mothballing pipelines used for wet crude, seawater or raw well water.
5.
Relating Mothballing Cost to Replacement & Maintenance Costs The economics of a mothballing procedure must be considered. More extensive initial mothballing expenses may reduce routine maintenance costs and/or equipment deterioration. If the cost of mothballing, recommissioning, and maintaining the equipment in a mothballed state is nearly equal to the cost of replacement or if the equipment is or may become obsolete, it should be a candidate for abandonment.
6.
Possibility of Obsolete Technology After Being Brought Back into Service Considerations should be given to the possibility that certain equipment (especially instrumentation) will be obsolete at the end of the mothball period. Obsolete in this context means that spare parts and/or competent servicing is either unavailable or excessively expensive.
7.
Availability and Cost of Maintenance Personnel A specific piece of equipment, such as an electric motor driven pump, mothballed within an operating plant can be routinely inspected and serviced by the plant operators with little additional cost/effort. The same pump located on an offshore GOSP which has been mothballed in its entirety would not routinely have personnel available to perform frequent mothball maintenance checks.
8.
Availability of Protective Media The availability of the protective media for mothballing must be considered. For example, nitrogen may be generated within one facility and be the obvious choice as an inert media while another location may not have nitrogen readily available; however, dry, sweet gas or dry crude may be convenient to use as an inert media.
9.
Storage Facilities Availability of local (plant) storage facilities may encourage inside storage of equipment such as small pumps, instruments, etc. rather than leaving them in place.
10.
Security Measures to Control Loss of Equipment Measures to control reutilization of mothballed equipment should be part of a mothball procedure. In most cases, equipment reutilization (cannibalization) should be discouraged in short-term mothballing, strictly controlled in long-term situations and actively encouraged in minimum first cost mothballing.
11.
Time Required for Mothballing It may take significant time to develop an appropriate mothball plan for a facility. The implementation of different mothballing techniques requires different times. If time is unavailable for proper planning and execution of mothballing procedures, more costly solutions should be expected.
Table 1 - General Categories For Mothballing
Short Term Mothball
Long Term Mothball
Minimum First Cost Mothball
Time out of service
1/2 to 3 years
Over 3 years
Over 5 years
Time to restart (Snap back time)
Less than 3 months
6 to 12 months
1 to 2 years (Major reconstruction)
Mothballing Cost
Medium
High
Low
Mothballing Maintenance Cost
Significant
Some
None
Cannibalization
Not permitted
Strictly controlled
Encouraged
Restart Cost
Low
Medium
High
Electric Power Required
Yes
Yes
Only for Cathodic Protection,Lights & Communications
Instrument Air
On or Off
Not available
Not available
Control House A/C
On usually
Off usually
Off
Instrument Power
On usually
Off usually
Off
CHAPTER III CORROSION OF MOTHBALLED EQUIPMENT AND PIPELINES
GENERAL Oilfield equipment including that used in oil, gas and water production, as well as processing and transportation facilities, is designed for operational conditions of pressure, temperature and flow. When such equipment is shutdown, it can experience far more damage in a short time period than in several years of normal operation. Operating corrosion rates of less than 3 mpy can suddenly increase to 100 mpy during shutdown periods. While relatively high corrosion rates may be tolerated for short term shutdowns, they are unacceptable in mothballed facilities. A.
EXTERNAL CORROSION 1.
Cathodic Protection Cathodic protection systems must remain active for mothballed equipment to retain its expected life.
2.
Insulated Lines/Vessels Insulated systems are normally at a relatively constant temperature during routine operation which prevents moisture accumulation beneath the insulation. Without moisture there is minimal corrosion and therefore many insulated pipes an d vessels have no protective paint or coating; however, in the presence of variable ambient temperatures, moisture may penetrate insulation and cause severe corrosion of the underlying steel if it is uncoated or unpainted. When an insulated facility is mothballed, it should be determined if underlying steel is p rotected via a coating. For short-term mothballing of coated or non-painted system, the insulation should be inspected and repaired to reduce the probability of moisture penetration. For both short-term and long-term mothballing of insulated unpainted systems located offshore or in shoreline facilities, annual inspection of the insulation and underlying steel (via exposed windows) is recommended. Insulated painted systems should be inspected every two years. If corrosion is detected insulation should be removed and the damage repaired. For insulated unpainted systems strong consideration should be given to removing the insulation from the piping and/or vessels undergoing long -term mothballing in offshore and humid areas since it is unlikely that corrosion will be avoided in these locations; however, it is recommended that insulation be left in place over coated/painted systems in all locations.
3.
Paint Systems Paint systems should be maintained for short-term and long-term mothballing for corrosion prevention and/or aesthetics. No paint maintenance should be considered in minimum cost mothballing.
4.
Sand Control Drifting sand will cover plant equipment not designed or protected for buried service and therefore may limit access to the facility. If wet salts are contained in the sand, a highly corrosive environment may occur. In general, however, drift sand is dry and will cause only minor damage to piping/vessels etc. Since the cost of the damage may be small compared to the costs involved in removing the sand. sand control efforts should be limited to those required to maintain facility/equipment access for routine mothball maintenance. Sand removal for protection against corrosion should always be justified from an economic standpoint.
B.
INTERNAL CORROSION 1.
Wet Systems Equipment mothballed with free water present in the mothball media are 'wet systems'. The presence of water causes concern because of three possible mechanisms for corrosion attack: oxygen, acid, and sulfate reducing bacteria (SRB). •
Oxygen -- metal exhibits anodic and cathodic sites. Iron dissolves at the anode when an electrolyte (water) is present. During this reaction, hydrogen is formed at the cathode which may eventually stifle the reaction (polarization). When oxygen is present, however, it combines with this hydrogen and allows the reaction to continue (depolarization). The initial oxygen dissolved in a water-filled vessel or pipeline will be consumed very quickly (in the corrosion process) and does not do significant damage while continued oxygen (air) ingress in a wet system will significantly increase corrosion rates. Air plus sulfides left in mothballed systems can give polythionic acids which are very corrosive and damaging to stainless steel. Organic corrosion inhibitors added to the mothballing fluid are ineffective in controlling damaging corrosion in the presence of oxygen. Oxygen ingress must be prevented in a wet system since oxygen scavengers in the mothballing fluid will rapidly be consumed if continued oxygen ingress is allowed.
•
•
Acid -- H2S and/or CO2 from sour crude or in produced water can cause water in these systems to become acidic. With the exception of sulfur handling areas, severe acid attack is not anticipated in Saudi Aramco's mothballed facilities. SRB -- sulfate reducing bacteria can become active in water systems that contain less than 10% dissolved salts and are oxygen free. These bacteria populations can cause pitting corrosion by producing acid; however, they require sufficient water to cause significant damage. In mothballed systems containing only a small amount of water (i.e. a gas filled system which has been drained but not dried), SRB's will cause insignificant damage.
Water can be made biocidal via high pH (above 10) or use of chemical biocides. If both biocides and oxygen scavengers are used, a check must be made on their compatibility. Using high pH (above 10) water will prevent bacterial attack throughout an extended mothball period. Since chemical biocides will degrade over time their initial concentrations must be calculated and enough biocides added to last throughout the mothball period or the biocides must be recharged based on corrosion monitoring and bacterial population assessment. Biocides presently in use have a half-life of about 6 - 9 months. Biocides are more effective in killing free floating bacteria than bac teria 'hidden' under slime and/or scale on the pipe or vessel wall. Water systems that have been in operation for an extended period of time often have established SRB colonies. In such cases, biocides even in very high concentrations will not sterilize these systems. In systems which have not been in operation, biocides added to the initial fill fluid may give sterilization, thus retreatment after biocide degradation is unnecessary. 2.
Dry Systems Equipment mothballed with the moisture content of the media controlled to avoid corrosion are known as 'dry systems'. Dryness can be specified as a dewpoint or in terms of relative humidity. In general, severe corrosion will not occur without "free water" present. Setting a dewpoint below what can be expected for ambient temperature (e.g. + 30 deg F) conditions will ensure that free water will not be present. In relatively insensitive equipment, such as pipelines, tanks and vessels, this specification is sufficient. Equipment which previously contained high salt content fluids, however, will retain a layer of salts on the metal surfaces. These salts are hygroscopic and can cause corrosion without freewater. In this case the equipment should either be cleaned prior to mothballing (water washed, steamed out or chemically cleaned) or the specified dewpoint should be lowered to -40 deg F. Equipment containing electrical contacts (e.g., instrumentation), thin walled exchanger tubing and machined surfaces is very sensitive to damage from minor corrosion. A very dry atmosphere (-30 deg F dew point) or a controlled relative humidity of 40 percent is required to ensure protection of sensitive equipment.
3.
Ambient Systems Ambient systems are essentially dry systems with the dewpoint or relative humidity uncontrolled. If the temperature drops below the dewpoint of the air and condensation occurs, the condensate will reevaporate when the temperature rises above the dewpoint. In the relatively dry climate surrounding onshore facilities in Saudi Arabia, ambient mothballing may provide a good solution for equipment which is not sensitive to corrosion.
CHAPTER IV PLANNING OF MOTHBALL PROCEDURES
It is recommended that a Mothball Team be established to develop specific procedures for mothballing and recommissioning. This task force should be selected from experienced maintenance, engineering and operating personnel who will be assigned to write specific mothball procedures for the related facilities and/or pipe-systems in their responsible area. The initial objectives of the task force should be: 1.
Identify mothballing options and alternatives, using this Mothball Manual for guidelines.
2.
Obtain feedback on recent plant mothballing problems.
3.
Recommend the general philosophy to be followed in mothballing (short-term, long-term, or minimum first cost) the subject facilities.
4.
Provide mothball cost estimates, recommissioning costs and option comparisons.
5.
Obtain Management approval of philosophy and selected option.
6.
Write specific procedures for initial mothballing, inspection/maintenance and recommissioning.
7.
Clearly define the assumptions used for developing the procedures and define the responsibility for ensuring that the assumptions do not change. Several different technical specialties may be required to develop a complete mothball procedure for a facility. These specialties would include electrical, instrumentation, rotating equipment, corrosion,inspection, vessels/piping/exchangers, petroleum engineering and utilities. The mothball team should be organized to develop procedures based on each individual's functional specialty rather than on administrative areas. Any routine mothball inspection/maintenance required should be an integral part of the mothball procedure with responsibility for record keeping during the mothball period and third party audit procedure clearly established. Since mothballing is often accompanied by manpower reductions and personnel transfers, ensuring that the maintenance tasks specified are performed continuously throughout the mothball period is difficult.
Because the economics involved in mothballing will normally be based primarily on poorly defined assumptions, the requirement or value of a short recommissioning period and the expected downtime must be established (more often assumed) in order to develop cost effective procedures. After these basic assumptions are made, the choice of specific procedures will often be made from uncertain probabilities. For example, a system can be dried effectively or be left water filled with oxygen excluded and SRB's controlled over a 'long' period. Every one or two years a review of assumptions used and procedures in effect is required to ensure a system is effectively mothballed.
CHAPTER V PROTECTIVE MATERIALS FOR MOTHBALLING A.
INERT MEDIA In order to make an environment virtually noncorrosive during the mothball period, one can choose a number of alternatives. These vary from (a) monitoring positive pressure of the process fluids to (b) replacement of corrosive process fluids with an inert media. Inert is defined as a media which is noncorrosive for oilfield applications and may include: 1.
Nitrogen (N2) Nitrogen is an inert gas and is available as bulk, liquified nitrogen, type II; and gaseous nitrogen, type 1 grade C class 1 per Fed. Spec. BB-N-411b. The later is provided in cylinders (180 SCF; cost $10 each) equivalent to $0.06/SCF gaseous N2. Experience with mothballed plants indicates some maintenance effort is required to ensure nitrogen pressure. Nitrogen (or other dry gases) tend to dryout and degrade packing material and flange gaskets; therefore, these must be checked regularly in order to control leakage which can be detected with a leak detector or a soap solution. When leaks are detected, valves must have packing tightened or replaced and flanges and/or threaded connections must be sealed. Intervals between repressurizing will increase with time from four to eight months, perhaps longer. Using a liquid N2 source is recommended if available. The advantages of using nitrogen are: • •
nonflammable and nontoxic. readily available in bulk as liquified nitrogen type II and gaseous nitrogen type I.
Disadvantages are: • •
2.
tends to dry out seals and packing leaks must be controlled
Dry Sweet Fuel Gas Dry means no free water is initially present or will conde nse from the gas during the mothball duration. Normally a maximum dew point is specified with the specification adjusted to match the mothball requirements.
The advantage of using dry fuel gas is: •
inexpensive and readily available at certain locations
Disadvantages are: • • • • •
3.
flammable can form explosive mixture with air more expensive than nitrogen in some locations leaks must be controlled tends to dry out seals and packing
Dry Air Dry air is an excellent mothball media if the system is initially dry or can be thoroughly dried during the mothballing process. The system should be maintained at a dewpoint of +30 deg F or lower or the relative humidity controlled to 40 percent or less. The advantages of using dry air are: • • • •
nonflammable nontoxic no problems with disposal facilitates internal inspection
The disadvantages are: • • • •
4.
may be expensive positive pressure may be difficult to maintain if very low dew point is required, it may dry out seals may form explosive mixture with hydrocarbons
Other Hydrocarbons Hydrocarbons such as diesel, kerosene or nominally dry crude are good protective materials although they sometimes need the addition of corrosion inhibitors to ensure protection against any water which may be present in the system at the time of mothballing. Hydrocarbons tend to wet flange gaskets and valve packing which expands the material and seals against leaks. Since leaks are easily detected, timely remedial action can be taken to prevent loss of these mothball media. Some water may settle out from these liquid hydrocarbons, and monthly draining at low points is recommended until no further water is found. Quarterly check for water should be conducted thereafter. The advantages of using hydrocarbons are:
• • •
Saudi Aramco's experience in their use, (depending on location). readily available reusable (in some locations)
Disadvantages are: • • • •
5.
flammable disposal problems (depending on location) Toxic Hydrojetting will be required before recommissioning to remove sheets of rust formed on the metal due to the water present in the hydrocarbons
Water While water is normally not considered inert, with proper conditioning it may be used to mothball systems and an acceptable corrosion rate can be maintained. The use of water for long term mothballing is questionable since biocides, added to prevent the growth of sulfate reducing bacteria, decompose with time. This allows SRB colonies to grow and they may present a pitting problem. If the mothballed facility is recommissioned before the biocide has been allowed to decompose, a biocide disposal problem may be encountered because even a low concentration of these chemicals can pose an environmental hazard. A system mothballed with water should also be kept under positive pressure (nitrogen or sweet gas) to prevent pitting damage caused by oxygen (air) ingress. The advantages of using water are: • •
inexpensive readily available
The disadvantages are: • • •
possibility of pitting corrosion by SRB disposal problems if biocide is present air ingress must be prevented by positive nitrogen or gas pressure
6.
Ambient Air Ambient air is not inert since condensation can occur when the ambient temperature drops significantly. When the temperature rises again, however, the condensed water will evaporate. In the onshore areas, the percentage of time that free water exists in a system due to condensation may be relatively short and even high corrosion rates during that period are acceptable. Ambient air mothballing allows inspection of the facility and, if corrosion is occurring, corrective measures may be taken. The advantages of using ambient air: • • • •
inexpensive readily available accessibility of equipment to inspection nonflammable
The disadvantages are: •
condensation of water will cause corrosion
Table 2 - Materials For Mothballing Advantages And Disadvantages Mothball Media
Cost
Availability
Advantages
Disadvantages
1. Motrpgem (N )
Bulk $2.80/liq gal $0.03/SCF or cylinders ease of disposal
Available in tank truck, contaner noncorrosive,
Safe, nontoxic, nonflammable, required
Dries out gaskets; pressure maintenance
2. Fuel Gas
Depends on location
Depends on location disposal
Inexpensive where available easy of moisute
Flammable; may be corrosive in presence
3. Dry Air (dew
Depends on
Readily available
Nontoxic, non-
May be costly
point +30 deg F
amount and
in most locations
corrosive in
to -40 deg F
source; lower the dew point the more expensive flammable; facilities inspection
absence of moisture; easy disposal; non-
4. Other hydrocarbons including dry crude and diese
Depends on location
Depends on location
May already be present at locations (process fluid)
Flammable, may have disposal problems
5. Water
Inexpensive where available
Depends on location nonflammable
Relatively nontoxic (if biocide free);
Sensitive to air (oxygen) ingress; potential SRB corrosion
6. Ambient Air
Least expensive
Facilities Inspection low cost
Corrosion uncontrolled
2
B.
PROTECTIVE COATINGS Coating metal surfaces provides a protective barrier between the metal and the environment and therefore allows the equipment to be placed in an ambient environment of air and/or water where it provides added insurance from corrosion. A coating can be a relatively permanent industrial maintenance type paint or a rust preventative grease or oil. The application of permanent coatings (epoxy, paint, etc.) is generally not recommended for mothballing because of the cost involved; however, insulated vessels or piping which have the insulation stripped and are unpainted may be an exception. Rust preventative greases and oils are relatively inexpensive to apply and remove but generally provide protection for only 6 to 18 months. Vapor phase inhibitors (VPI) are more effective in small enclosures and vessels where v apor leakage is minimum. VPI's which vaporize effectively in warm climates have a limited life (one to two years per vendor's literature), but, they may also render the enclosed atmosphere toxic. A listing of coating materials, and stock numbers is shown in Appendix B.
C.
HOUSINGS AND COVERINGS Protective housings and coverings may be applied to reduce deterioration from the environment. These may be plywood boxes constructed over rotating equipment, tape coverings over exposed motor/pump shafts, or polyethylene bags over instruments (inside only). If this type of protection is vapor tight, it keeps dust, sand, rain, dew and salts from exposed surfaces. Coverings will also retard oxidation or 'drying out' of greases or oils applied to machined surfaces. Covering of motor, turbine, and compressor air inlets and taping over applied protective greases is recommended. Polyethylene film should not be used outdoors because it deteriorates rapidly. If the equipment is designed for outside exposure, constructing box enclosures and/or using plastic bags is generally not encouraged. A listing of covering materials sealants and their stock numbers is shown in Appendix B.
D.
COCOONING Both internal and external surfaces can be protected by proper storage of equipment in covered and, if required, conditioned-air enclosures. The equipment can be moved to environmentally controlled storage, or in situation where this is not feasible, a cover can be installed over the equipment in place. A noncorrosive environment can be maintained within the cover by using a patented CocoonTM method which utilizes a network of wire over which PVC is sprayed.
The environment is maintained by circulating controlled-humidity (40%) air between the Cocoon and the surface of the protected equipment. Since this air is also circulated inside the equipment, both internal and external protection is provided. Automatically controlled air driers maintain moisture content below the c orrosion level. The "Cocoon" method enables immediate recommissioning. The initial cost for Cocooning expensive rotating equipment in Saudi Arabia is estimated to be 1-3 percent of its capital cost. This cost will vary with the location (offshore or onshore), and configuration of the equipment.
CHAPTER VI GUIDELINES FOR MOTHBALLING OF SPECIFIC EQUIPMENT AND FACILITIES
1
WELLS 1.1
Basic Considerations Wells are separated into the following types for mothballing considerations: 1. 2. 3.
Oil Wells Water Wells Gas Wells
Sand encroachment at well heads should be monitored periodically and sand removed when it restricts well access. Routine annulus pressure surveys and xmas tree valve maintenance should be continued on mothballed wells, and the wells should be blinded at the wellhead with on-plot piping treated as part of the well flowline or lateral (TABLE 3). 1.2
Oil Wells No action is required for mothballing oil wells since shut-in oil wells are generally under positive pressure which excludes oxygen ingress, water in wet wells sinks to the bottom, and the gas phase in some fields is sour but not very aggressive in the absence of oxygen.
1.3
Water Wells A.
Potable Water Wells: •
•
Free flowing: Positive pressure in the well will prevent oxygen ingress and severe corrosion attack. Adding chemical inhibitors or biocides or displacing the well with diesel is not recommended due to potential toxicity problems on start-up. Non-free flowing: Nitrogen purge (cycle pressure to 30 psig two times) and leave with 30 psig pressure to exclude oxygen. No pressure monitoring or repressurizing is recommended. Oxygen ingress (breathing) is expected to be minimal during short or longterm mothball. Chemical or oil addition is not recommended due to potential toxicity problems.
B.
Non-Potable Water Wells (Injection and/or Supply) Oxygen Ingress •
•
Free flowing: Oxygen ingress into supply wells will be effectively controlled by positive wellhead pressure. Injection wells may lose their pressure after an extended period and may require nitrogen purging for long-term mothballing. A pressure survey is recommended with quarterly surveys for the first year an d annual surveys thereafter. Non-free flowing: Nitrogen purge (cycle pressure to 30 psig two times) and leave with 30 psig pressure to exclude oxygen. No pressure monitoring or repressurizing is recommended since oxygen ingress (breathing) is expected to be minimal.
Chemical treating/fluid displacement: Adding corrosion inhibitor or biocide to the well bore fluid is advantageous since it will aid in reducing corrosion and reduce the possibility of SRB attack during the mothballing period. A concentration of 300 ppm of a filming amine corrosion inhibitor and 300 ppm quarternary amine biocide is recommended. Retreatment after three or more years may be required (based on corrosion monitoring) for long-term mothballing. For minimum first cost mothballing, retreatment is not recommended since SRB attack is a potential problem and not a certainty. A second option is to displace the water in the well bore partially or fully with inhibited diesel. This will better protect the tubulars from corrosion and avoid SRB and the need for retreatment. An additional recommissioning cost will be incurred for diesel filled injection wells since the diesel should not be injected into the formation and therefore must be backflowed or, in some cases, circulated out of the well. Corrosion Monitoring: Semi-annual coupon analysis, sessile and planktonic SRB count, and water analysis for total iron are recommended to track the success of the mothball program in both short-term and long-term mothballing. These analyses are not recommended for wells that have water displaced by diesel. 1.4
Gas Wells Deep, sour gas wells should be mothballed by shuting in with diesel or inhibited brine. Cap gas wells should be mothballed with inhibited diesel or inhibited brine for long-term and minimum first cost mothballing. Both should be shut-in with no treatment for shortterm mothballing.
Table 3-A Wells Mothballing Facility
Short Term
Long Term
Minmum First Cost
1.
Oil Wells
-
Shut in under positive pressure
-
-
Same as short term
2
Water Wells
-
Remove submersible pumps, preserve and store
a.
Potable water wells free flowing
-
No treatment
-
No treatment
-
No treatment
b.
Potable water wells non-free flowing
-
Purge with N 2 Lease with 30 psig pressure Do not treat with chemicals or oil
-
Same as short term
-
Same as short term
No treatment
-
No treatment May require N2 purging
-
No treatment
-
Same as short term Annual pressure survey
-
None
-
None
-
Replacement of tubular goods as required
c.
Non-potable water wellsfree flowing
-
Maintenance/ Monitoring
-
Recommissioning Concerns
-
Purge with N2 if needed - Semi annually with well head coupons and SRB count None
Same as short term
Table 3-B Wells Mothballing Facility
d.
Non-potable water wells non-free flowing
Short Term Long Term
Minmum First Cost
-
Purge with N2 Leave with 30 psig pressure Treat with inhibitor or biocide (300 ppm) Treat with inhibited diesel
-
Same as short term
-
Same as short term
Same as short term Retreat with inhibitor or biocide 3 year interval
-
None
-
3.
Monitoring/ Maintenance
-
Semi annually with well head coupons and SRB count
-
Recommissioning concerns
-
None
None
-
Replacement of tubular goods as required
-
Gas Wells a.
Deep, sour gas wells
-
Shut in with inhibited brine or diesel
-
Same as short term
-
Same as short term
b.
Cap gas wells
-
Shut in No treatment
-
Shut in with inhibited diesel or inhibited brine
-
Same as long term
2
PIPELINES 2.1
Basic Considerations Pipelines are divided into the following types: Flowlines Crude Transmission Lines Wet Gas Transmission Lines Dry Gas Transmission Lines NGL & Hydrocarbon Condensate Lines Water Supply/Injection Lines Utility Lines • • • •
Potable Water Steam and Steam Condensate Fire Water Instrument Air
In general pipeline protection during mothballing relies on the exclusion of oxygen and/or free water from the line. Where the line is left water filled, some provisions for SRB control is required (pH adjustment, chemical biocide treatment, Presence of high salinity e.g. flowlines). Cathodic protection systems, if present, must be left in operation. 2.2
Flowlines (Trunklines) Flowlines should be shutin under positive pressure (about 5 psig) to prevent oxygen ingress. If lines lose pressure the leak should be stopped and repressurized with nitrogen, hydrocarbon gas or crude. When checking for positive pressure the liquid head should be taken into account with checks performed at both ends of the flowlines. Because water will separate from the crude over a period of time, the high salinity (above 10%) of the produced water will prevent SRB growth and exclusion of oxygen should control corrosion to an acceptable rate. Corrosion can be further reduced, by injecting a water soluble filming amine type corrosion inhibitor (200 ppm) into the flowline prior to shutdown, or alternatively, the flowline fluid may be displaced with inhibited 'dry' crude back-flowed from the GOSP (the effectiveness of water displacement via this relatively low velocity back flowing is questionable). Experience with shutting in flowlines without chemical inhibition has been quite good; however, the majority of our experience has been with relatively dry
flowlines where only isolated failures have occurred. Therefore, on recommissioning, hydrotesting all flowlines shut-in longer than one year is recommended. Flowlines should not be hydrotested immediately prior to or during mothballing since residual hydrotest water can be far more damaging than wet crude. 2.3
Crude Transmission Lines Corrosion can take place where free water separates from the oil and will increase in the presence of deposits -- sand, sludge, scales. Therefore if facilities are available, freewater and deposits should be removed by scraping the line prior to mothballing. (Installing facilities expressly to scrape the line for mothballing is not economic). When scraping is not possible, flowing the line at a high velocity (greater than 3 ft/sec) in order to reduce accumulated water is recommended. Corrosion mitigation in crude transmission lines relies primarily on preventing oxygen ingress. The line should be fully isolated and mothballed full of crude and maintained with positive pressure (about 50 psig) to prevent oxygen ingress. Lines should be checked every six months in order to ensure the positive pressure is maintained. For short and long-term mothballing, repressurization with nitrogen, hydrocarbon gas or crude as required is recommended. The addition of corrosion inhibitors or biocides is not considered necessary since lack of oxygen and the natural inhibiting properties of the oil, will result in corrosion rates which should be acceptable. Not enough water will be present to support a damaging bacterial population. As an option, hydrocarbon gas can be used to displace the crude in the line. In general, this will not lessen the risk of corrosion since this is dictated by the success of the water removal/cleaning operation.
2.4
Wet Gas Transmission Lines Like crude transmission lines, corrosion mitigation in wet gas lines depends on preventing oxygen ingress and reducing the free water content of the line. Scraping prior to mothballing is recommended. Because these lines do not benefit from the inhibiting properties of crude oil, it is recommended coating the line with inhibitor prior to shut-in, by slugging inhibited diesel gel between two scrapers. A nominal pressure should be maintained in the shut in line by nitrogen or hydrocarbon gas. Corrosion should be monitored on a semi-annual basis by the use of coupons.
As an alternative, the line may be dried and filled with dry gas or nitrogen, Although this will reduce the risk of corrosion, it is not generally considered necessary; however, in long, large diameter undersea lines it may be worth the added protection due to high repair/replacement costs of these facilities. 2.5
Fuel Gas Transmission Lines Fuel gas transmission lines should not have an internal corrosion problem during mothballing. However, some pitting is to be expected at low spot due to condensed moisture. Scraping is recommended prior to mothballing (where facilities exist) to ensure the lines do not contain free water.
2.6
NGL and Hydrocarbon Condensate Lines Dry NGL or condensate lines may be shut-in under nominal positive pressure since the product is non-corrosive. If facilities exist, these lines may be scraped prior to mothballing in order to ensure the absence of free water. Wet NGL or condensate lines should be scraped if possible prior to shut-in. It is recommended that a filming amine type corrosion inhibitor be added for short and long-term mothballing or as an alternative, the line may be dried and filled with dry hydrocarbon gas or nitrogen. As with wet gas transmission lines, this will reduce the risk of corrosion but this alternative is not recommended in most cases.
2.7
Water Supply/Injection Lines Successful mothballing of water supply/injection lines requires the prevention of oxygen ingress. Bacterial corrosion control is also a real potential problem. Scraping is recommended prior to mothballing since corrosion is likely to form under deposits. For short-term mothballing the water should be treated with a filming amine type corrosion inhibitor. A high concentration 50-100 ppm of a water soluble type is preferred; although oil soluble, water dispersible products generally are better film formers, they are likely to separate under stagnant conditions. In addition to the corrosion inhibitor, a biocide treatment is recommended. Because biocides degrade fairly quickly (half-life 6-9 months), information on the particular product's degradation and minimum effective concentration (usually 50 - 100 ppm) is required in order to determine its initial concentration.
For long-term mothballing, bacterial control can be ensured by replacing the treated water when the biocide has degraded to an ineffective level and the corrosion rate and the bacterial population counts indicate an upward trend. In general, this will not be as cost effective as displacing the water with hydrocarbon gas or nitrogen and mothballing the line as a wet gas line. Consideration may also be given to draining and drying the line and using dry air or dry gas as a mothballing medium. Biocide treatment should be deleted for minimum first cost mothballing. Although this will increase the risk of corrosion via SRB's, routine corrosion monitoring with coupons for SRB attack will help reduce concern. It must be understood, however, that severe corrosion may occur in parts of the line and not on the coupons. Oxygen ingress must be prevented in the minimum first cost case (otherwise the facility has been abandoned) and scraping and corrosion inhibitor are recommended as being cost effective. Coupon monitoring, SRB counts (both planktonic and sessile) and, where applicable, biocide residual testing is recommended every six months for water filled systems. 2.8
Utility Lines 2.8.1
Potable Water Potable water lines should be drained and, if possible blown dry since residual water trapped in the system will result in corrosion and probably require line repair. Displacing the water with nitrogen will reduce the risk of corrosion but may not be cost effective in small systems. Chemicals are not recommended due to toxicity problems on start-up. If the line is left filled with water, oxygen must be excluded and corrosion via biological attack is possible.
2.8.2
Steam and Steam Condensate Hot steam lines should be blown with air and shut-in since the line's heat will dry the line and Additional protection may be gained by using nitrogen in addition corrosion will be minimal in dry air. to the air but, unless the nitrogen is readily available, this insurance seems unwarranted. Hot condensate lines may also be blown dry and effectively preserved. Water in cold condensate lines should be displaced with nitrogen. They can be left full of water and oxygen excluded. However, removal of the water is preferred. Oil and/or oily corrosion inhibitors are not recommended in these systems.
2.8.3
Fire Water Fire water systems should be shut-in as is and oxygen ingress prevented.
2.8.4
Instrument Air Instrument air is dry and not corrosive. These systems can be shut-in without special measures.
Table 4-A Pipelines Mothballing Facility
Short Term
Long Term
Minimum First Cost
1.
General
General
General
-
Keep C.P. in operation Do not remove sand dunes Do not hydrotest lines prior to mothballing
-
Same as short term
-
Same as short term
Add a water soluble filming amine type corrosion (200 ppm) to crude (wet or dry) Shut-in under positive pressure (about 5 psig) If needed, repressurize with nitrogen hydrocarbon gas or crude Back flow inhibited dry crude from GOSP with WCHF if water cut is 30 percent or more
-
Back flow dry crude with inhibitor from GOSP with WCHF Shut-in and repressurize same as short term
-
Add inhibitor to crude
None
None
-
Pitting expected at low points
Flowlines
-
-
Recommissioning concerns
-
-
-
WCHF - Wet Crude Handling Facilities
Table 4-B Pipelines Mothballing Facility
Short Term
Long Term
Minimum First Cost
2.
-
If facilities are available, scrape to remove free water and deposits Leave line full with crude under positive pressure (about 50 50 psig) Do not add corrosion inhibitor or biocide
-
-
Same as short term
-
-
None
-
Check pressure every 6 months If needed, repressurize with nitrogen, hydrocarbon gas or crude
-
None
None
-
Pitting expected at low points Replacement likely
Crude Transmission Lines
-
-
Monitoring/ Maintenance
Recommissioning concerns
-
-
Same as short term
Alternatives - Scrape to remove water and sludge - Displace crude in line with nitrogen gas preferred) - Maintain positive pressure Check Pressure every 6 months if dry gas procedure is used
-
Table 4-C Pipelines Mothballing Facility
Short Term
Long Term
Minimum First Cost
3)
-
If facilities are available, scrape to remove free water and deposits
-
-
Same as short term
-
Coat line with a slug of inhibited diesel gel
-
-
Add 3 phase inhibitor
-
Shut in under positive pressure
-
-
Check pressure every 6 months If needed, repressurize with nitrogen or dry gas Semi annually corrosion monitoring with coupons None
-
Same as short term Check only pressure every 6 months if nitrogen or dry gas procedure is used
-
None
-
None
-
Replacement likely
Wet Gas Transmission Lines
Alternatives
-
Monitoring/ Maintenance
Recommissioning concerns
-
Same as short term
Scrape to remove water and sludge Displace wet gas with nitrogen or dry fuel gas Shut in under positive pressure
Table 4-D Pipelines Mothballing
Facility
Short Term
Long Term
Minimum First Cost
4)
-
If facilities are available, scrape to remove free water and deposits Shut-in under positive pressure
-
Same as short term
-
Same as short term
-
Same as short term
-
None
-
Check pressure every 6 months If needed, repressurize with nitrogen or dry gas
-
None
-
None
-
Pitting expected at low points
Fuel Gas Transmission Lines
Monitoring/ Maintenance
Recommissioning concerns
-
Table 4-E Pipelines Mothballing Facility
Short Term
Long Term
Minimum First Cost
5)
NGL and Condensate Lines
-
If facilities are available, scrape to remove free water
-
-
Same as short term
A) Dry
-
Shut-in under positive pressure
B) WET
-
If facilities are available, scrape to remove free water
-
Shut in under postive pressure
-
Add a filming amine type corrosion inhibitor Shut in under positive pressure
Monitoring/ Maintenance
-
Recommissioning concerns
-
Same as short term
Alternatives - Evacuate and fill with nitrogen or dry fuel gas -
Same as short term
Alternatives - Evacuate and fill with nitrogen or dry fuel gas
Check pressure every 6 months If needed, repressurize with nitrogen or dry sweet gas Semi annually corrosion monitoring with coupons
-
Same as short term
-
None
None
-
None
-
Pitting expected at at low points
Table 4-F Pipelines Mothballing Facility
Short Term
Long Term
Minimum First Cost
6)
-
-
-
Well Water Supply and Injection Lines
-
-
-
If facilities are available, scrape to remove deposits Treat with a filming amine type corrosion inhibitor and/or biocide depending upon the water source A high concentration (50 - 100 ppm) of a water soluble type is preferred Prevent oxygen ingress
Same as short term Replace treated water when biocide has degraded to ineffective level
-
Same as short term Do not treat with biocide treat with biocide Prevent ingress of oxygen
Alternatives - Displace the water with hydrocarbon gas and mothball the line is as a wet gas line or - Displace the water with air - Dry the line - Lay-up with nitrogen dry air or dry sweet gas
Monitoring/ Maintenance
-
Semi annually coupon monitoring SRB counts and biocide residual testing
-
Same as short term where applicable
-
None
Recommissioning concerns
-
None
-
None
-
Replacement likely
Table 4-G Pipelines Mothballing Facility
7
Short Term
Long Term
Minimum First Cost
-
-
Same as short term
-
Same as short term
Utility Lines a)
Potable Water
-
Drain lines and below dry if possible Do not treat with chemicals Prevent ingress of oxygen if lines cannot be drained
Alternative -
Displace water with nitrogen
Monitoring/ Maintenance
-
None
-
None
-
None
Recommissioning concerns
-
None
-
Some pitting
-
Replacement likely expected if lines lefter water filled
b)
-
Drain lines and blow dry with air or nitrogen Shut in lines Do not treat with oil and/or oily corrosion inhibitors
-
Same as short term
-
Same as short term
Check every 6 months if oxygen ingress is prevented
-
None
-
None
Steam and Steam Condensate
Monitoring/ Maintenance
-
-
Table 4-H Pipelines Mothballing Facility
Short Term
Long Term
Minimum First Cost
Recommissioning concerns
-
None
-
Some pitting is expected if lines not properly drained, dried and effefitively preserved
-
Replacement likely
c)
-
Leave full Shut in Prevent oxygen ingress
-
Same as short term
-
Same as short term
Monitoring/ Maintenance
-
None
-
None
-
None
Recommissioning/ concerns
-
Replacement likely
-
Same as short term
-
Same as short term
d)
-
Shut in without special measures
-
Same as short term
-
Same as short term
Monitoring/ Maintenance
-
None
-
None
-
None
Recommissioning concerns
-
None
-
None
-
None
Fire Water
Instrument Air
3
VALVES 3.1
Basic Considerations 3.1.1
General The mothballing procedures for the preservation and maintenance of valves are dependent mainly on the size and type of valves, and the recommissioning period specified. Mothballing procedures will involve one of the following :
3.1.2
1)
Preservation of the entire valve including those with hydraulic, pneumatic or electric actuators.
2)
Preservation of the valve in-line, but with some vulnerable components removed and stored in a controlled atmosphere.
Types of Valves The following types of valves are considered: 1. 2. 3. 4. 5. 6. 7. 8. 9.
3.1.3
Gate Valves Ball Valves Check Valves Plug Valves Butterfly Valves Safety Valves Relief Valves Pressure Control Valves Air Relief Valves
Some Specific Concerns and Considerations 3.1.3.1
The majority of valves are installed in process-piping and/or process pressure vessel equipment. A smaller number of valves, in general larger in size and expensive, are installed in pipelines (Crude or Gas transmission lines).
3.1.3.2
When a plant or facility is mothballed, valves should normally not be removed and, they will be internally subjected to the mothballing media in the connected piping.
3.1.3.3
Preservation of valves in situ has the following advantages:
-
-
3.1.3.4
3.1.4
Covering valves and/or actuators with plastic bags is generally ineffective and not recommended, because the plastic bags or polyethylene wrappings deteriorate rapidly, and they will collect sand and moisture.
Recommendations 3.1.4.1
Internal preservation -
3.1.4.2
Treat valves the same as connected piping or pipelines. Leave valves, where applicable in (half) open position. Drain valves when applicable and feasible.
External preservation -
3.1.5
No dismantling costs No indoor storing costs No identification problems Most valves, located in a processing facility are an integral part of the process equipment and its associated piping and will be subjected to the selected lay-up. Snap-back period for recommissioning will be relatively short. The disadvantage of valves in situ are: Replacement of components, such as soft sealing, will generally be required after long-term mothballing is terminated. These components can be easily replaced, however and spares should be made available from stock when termination of mothballing is expected.
Lubricate and grease stem bearings. Stroke after greasing (2 or 3 times). Leave in (half) open position. Tighten packing. Coat machined surfaces with rust preventative SAMS stock item 26-007-230/240 or equivalent. Coat stem and stem threads with Denso paste plus Denso tape. Fill gear-boxes with R.P.oil (V.P.I.). Leave diaphragm actuator in place. They should be recalibrated during commissioning and replaced at that time if necessary. Remove oil, coat, and store piston actuators.
Monitoring Maintenance
3.1.5.1
Short Term Mothballing -
3.1.5.2
Long Term Mothballing -
3.1.5.3
Do not stroke Determine if packing requires re-tightening when checking pressure of the mothballing medium. Add Denso paste/tape or equivalent if required.
Same as Short Term, but discontinue onitoring/maintenance after three years.
Minimum First Cost Mothballing -
Monitoring/maintenance is not recommended.
Table 5 Valves Mothballing Facility
Short Term
Long Term
Minimum First Cost
Internal
-
Same as connected piping
-
Same as short term
-
Same as short term
External
-
Lubricate and grease Stroke after greasing Leave in half open position Wrap with Denso tape and Coat stem with Denso paste Do not wrap valves with plastic sheets or bages
-
Same as short term
-
Same as short term
-
Same as short term Discontinue monitoring after three years
-
None
-
Semi annually Add Denso paste as required Do not stroke
-
None
-
Replacement of seat, gears or actuators likely
-
Same as long term
-
Monitoring/ Maintenance
Recommissioning concerns
-
4
PRESSURE VESSELS 4.1
Basic Considerations 4.1.1
General Pressure vessels, which are part of the process equipment, generally contain hydrocarbon products which can be either sweet or sour, dry or wet. The process side of the pressure vessels require specific mothballing procedures when the pressure vessels are mothballed for Short-Term, Long-Term or Minimum First Cost Mothballing. Mothballing procedures involve one of the following:
4.1.2
4.1.1.1
Preservation of the entire pressure vessel in situ, using the same lay-up medium as selected for the connected process piping.
4.1.1.2
Preservation of the entire pressure vessel in situ, but using a different lay-up medium than was selected for the connected process piping. For this option, pressure vessels must be isolated from associated piping with blinds.
Some Specific Concerns and Considerations 4.1.2.1
The majority of pressure vessels are made of carbon steel. Some are simple in construction and others, such as desalting traps in desalting facilities or columns in refineries, are complicated.
4.1.2.2
Some pressure vessels are made of stainless steel or cladded carbon steel, while some are made of carbon steel with an internal coating. These types of pressure vessels, when mothballed, present different concerns than pressure vessels made of carbon steel and without an internal coating.
4.1.2.3
Pressure vessels will normally not be removed from a plant and stored elsewhere when a plant is mothballed. The removal of the pressure vessels to other plants is encouraged when plants are mothballed at Minimum First Costs.
4.1.2.4
Preservation of pressure vessels includes internal protection and external protection. In general, external corrosion and/or
pitting is not expected providing normal paint schedule is continued. 4.1.2.5
Some pressure vessels are externally insulated, which may give reason for concern when vessels will be mothballed for Long Term. The insulation should be removed when serious corrosion on the steel surface is expected to occur or is revealed during monitoring. The external steel surface should be coated with a suitable paint after removal of insulation.
4.1.2.6
Lay-up mediums for pressure vessels are: • • • •
4.1.3
Nitrogen Diesel, with or without inhibitor Dry-air Ambient air
4.1.2.7
Dry fuel gas is recommended with care as a lay-up medium because it can form explosive mixtures with air.
4.1.2.8
It is recommended that the liquid from all pressure vessels be drained prior to mothballing.
4.1.2.9
Recommissioning concerns: Significant amount of loose and flaky rust will be present on all metal surfaces due to water present in diesel and oxygen in nitrogen. Hydro-jetting will be required before recommissioning.
Recommendations 4.1.3.1
Internal Preservation for Short and Long Term Mothballing -
Drain liquid Clean vessel, including boot-legs Isolate vessel from connected piping if required Fill with diesel or purge with nitrogen Seal vessel and maintain 5 psig nitrogen pressure for one year Check quarterly if water has collected - Continue checks after one year, annually
-
4.1.3.2
External Preservation for Short or Long Term Mothballing -
-
4.1.3.3
Drain liquid Purge with ambient air (avoid any fire hazards) Close vessel Do not steam out Do not repair Monitoring/maintenance not required
External Preservation for Minimum First Cost Mothballing -
4.1.3.5
Non-insulated vessels require no special treatment Continue normal paint schedule as required Insulated vessels should be protected by sealing off all openings in the weather jacket with plastic tape or mastic putty (Denso or equal type). Provisional windows may be cut in the insulation to enable monitoring of the underlaying steel surface. The windows should be sealed off effectively. Remove insulation if steel surface is corroding Paint steel surface in accordance with Saudi Aramco Paint Manual
Internal Preservation for Minimum First Cost Mothballing -
4.1.3.4
Check diesel leakage semi-annually and tighten gaskets or threaded connections when needed - Discontinue checks after one year
Insulated and non-insulated vessels do not require special treatment Discontinue normal paint schedule Do not remove insulation Monitoring/maintenance not required
Preservation of the Process Side by Continuous Dry-air
Purge Technically it is feasible to preserve the process side of pressure vessels and associated pipe work by purging them with dry air. With this option, dry instrument air - with a maximum relative humidity of 40 percent - should flow continuously through the process equipment and connected piping. The dry air can be supplied by instrument air compressors.
Instead of purging with dry air, the process equipment can also be internally preserved by circulating the dry air (40% relative humidity) through the process equipment and connected piping. This can be achieved by flowing the air in a closed circuit through an air-drier equipped with a fan. This option can be applied for short or Long Term Mothballing. It is, however, only recommended for use in plants or facilities which have been installed but not operated with hydrocarbon products. The advantages of using this option are: • • • • •
Nonflammable Nontoxic No problems with disposal Facilitates internal inspection Process side of pressure vessels and associated piping will not corrode
The disadvantages are: •
• •
Fans and air-driers are required (initial cost is expensive) Weekly monitoring of fans and air-driers is required Electric power is required
Table 6-A Pressure Vessels Mothballing Facility
Short Term
Long Term
Minimum First Cost
Internal
-
Drain liquid Fill with diesel or Purge with nitrogen or dry air
-
Same as short term
-
Drain liquid Purge with ambient air Close
-
Semi annually for diesel leakage or Maintain 5 psig pressure for one year Then discontinue monitoring
-
Same as short term
-
None
-
None
-
None
-
Pitting expected at low spots where water can collect
-
None
-
None
-
None
Monitoring/ Maintenance
-
Continue normal paint schedule
-
Same as short term
-
None
Recommissioning concerns
-
None
-
None
-
Pitting and/or general corrosion expected - Surface repair likely
Monitoring/ Maintenance
Recommissioning concerns External a)
Non-Insulated Vessels
Table 6-B Pressure Vessels Mothballing Facility
Short Term
Long Term
Minimum First Cost
-
Seal off all openings in weather jacket with plastic tape or mastic putty (Denso paste)
-
Same as short term
-
None
-
-
Same as short term
-
None
-
Semi annually Remove insulation if steel surface is corroding Paint steel surface
-
None
-
None
-
Pitting and/or general corrosion expected Surface repair likely
External b)
Insulated Vessels
Monitoring/ Maintenance
Recommissioning concerns
-
5
TANKAGE 5.1
Basic Conditions 5.1.1
General The following types of tanks should be considered when mothballing equipment: -
Floating roof storage tanks for hydrocarbon products at ambient temperature. Cone roof storage tanks for hydrocarbon products at ambient temperature. Cone roof storage tanks for water. Cone roof storage tanks for chemicals.
Mothballing procedures involve one of the following: A.
B.
C.
Floating Roof Tanks 1)
Preserve the entire tank in situ, but with crude level full or such that roof legs are 6 inchs from the tank bottom (Long and Short Term only).
2)
Leave tank empty, without monitoring and without maintenance (Min. First Cost only).
Cone Roof Tanks - Hydrocarbon 1)
Preserve the entire tank in situ, leaving the tank empty, and using desiccant as lay-up medium (Short or Long Term).
2)
Preserve the entire tank in situ, leaving the tank empty, without desiccant and without monitoring/maintenance (Min. First Cost only).
Cone Roof Tanks - Water Preserve the entire tank in situ, leaving the tank empty, after cleaning and drying (Short or Long Term or Min. First Cost). No monitoring/maintenance for Min. First Cost mothballing.
D.
Cone Roof Tanks - Chemicals
5.1.3.2
Preservation of Floating Roof Tanks for Minimum First Cost Mothballing -
5.1.3.3
Preservation for Cone Roof Tanks (Hydrocarbon) for Short or Long Term Mothballing -
5.1.3.4
Empty tank Clean and dry Continue normal painting schedule
Preservation of Cone Roof Tanks (Water) for Minimum First Cost Mothballing -
5.1.3.7
Empty tank Steam out and clean tank Purge with air or nitrogen Seal tank Do not install desiccant Discontinue monitoring and maintenance
Preservation of Cone Roof Tanks (Water) for Short or Long Term Mothballing -
5.1.3.6
Empty tank and open manways Steam out, clean and dry Use desiccant and breather valves Replace desiccant semi annually if desiccant is installed Continue normal painting schedule
Preservation of Cone Roof Tanks (Hydrocarbon) for Minimum First Cost Mothballing -
5.1.3.5
Recommendations for long term may be applied Discontinue paint maintenance
Empty tank Clean and dry Discontinue monitoring and maintenance
Preservation of Cone Roof Tanks (Chemicals) for Short or Long Term Mothballing -
Drain the chemical product in 55 gallon drums and use elsewhere Purge with air or nitrogen, if required to remove toxic vapors
5.1.3.8
Continue normal painting schedule
Preservation of Cone Roof Tanks (Chemicals) for Minimum First Cost Mothballing -
Drain the chemical product in 55 gallon drums and use elsewhere Purge with air or nitrogen, if required to remove toxic vapors Discontinue monitoring and maintenance
Table 7-A Tankage Mothballing Facility
Short Term
Long Term
Minimum First Cost
1.
-
-
Same as short term
-
Same as short term
-
Continue normal painting schedule In light product service and at low level, all internal surfaces to be sprayed with No. 5 or No. 6 oil fuel
-
None
None
-
General corrosion expected if tank is empty Internal & external repair likely
Floating Roof Tanks
Leave full of crude or Lower crude level
Alternatives
Monitoring/ Maintenance
-
Empty tank with roof on legs
-
Continue normal schedule
-
Recommissioning concerns
-
None
-
-
Table 7-B Tankage Mothballing Facility
2.
Short Term
Long Term
Minimum First Cost
-
Empty tank and open manways Steam out if required Purge with air or N2 to remove flammable or toxic vapors or gases Install desiccant
-
Same as short term
-
Same as short term Do not install desiccant
Continue normal painting schedule Replace desiccant semi annually
-
Same as short term
-
None
None
-
None
-
General corrosion expected Internal and external repair likely
Cone Roof Tanks a)
Hydrocarbon
Monitoring/ Maintenance
-
Recommissioning
-
Table 7-C Tankage Mothballing Facility
Short Term
Long Term
Minimum First Cost
-
Empty tank Clean and dry
-
Same as short term
-
Same as short term
Monitoring/ Maintenance
-
Continue normal painting schedule
-
Same as shor term
-
None
Recommissoning concerns
-
None
-
None
-
General corrosion expected Internal and external repair likely
c)
-
Empty tank Purge with air or N2 if required to remove toxic vapors Drain product in 55 gallon drums and use elsewhere
-
Same as short term
-
Same as short term
Cone Roof Tanks b)
Water
Chemicals
-
Monitoring/ Maintenance
-
Continue normal painting schedule
-
Same as short term
-
None
Recommissioning concerns
-
None
-
None
-
None
6
HEAT EXCHANGER EQUIPMENT 6.1
Basic Considerations 6.1.1
General The following types of heat exchanger equipment are considered for mothballing: -
Shell and Tube exchangers Fin-Fans (Air coolers) Evaporate Coolers (Combinaire)
The above types of heat exchanger equipment in general form part of the process equipment, and mothballing procedures for pressure vessels would therefore also be applicable to heat exchanger equipment. Mothballing procedures involve one of the following: 1)
2)
6.1.2
Some Specific Concerns and Considerations 1) 2)
3)
6.1.3
Preservation of the entire heat exchanger equipment in situ while using the same lay-up medium as selected for the connected piping. Preservation of the entire heat exchanger equipment in situ, but using a different lay-up medium as selected for the connected piping.
The specific concerns and considerations are also applicable to heat exchanger equipment. When mothballed at Minimum First Cost, there is concern for recommissioning of tubes in Shell and Tube heat exchangers and for tubes, fans, belts and motors installed in Fin-Fans. Replacement is likely. Wooden downcomers, installed in cooling towers, are of concern when mothballed and not removed. It is recommended the water system be circulated weekly when Short Term Mothballing is required. The wooden downcomers should be removed when Long Term or Minimum First Cost Mothballing is required.
Recommendations 6.1.3.1
Preservation of Shell and Tube Heat Exchangers for Short Term, Long Term and Minimum First Cost Mothballing -
Remove free water
-
6.1.3.2
Preservation of Fin-Fans for Short Term or Long Term Mothballing -
6.1.3.3
Treat as pressure vessels Monitoring and maintenance remain the same as for pressure vessels Recommissioning concerns remain the same as for pressure vessels, but tube replacement likely when mothballed at Minimum First Cost.
Remove free water Treat tubes internally installed in Shell and Tube heat exchangers If Fin-Fans are located offshore and mothballed for Long term, spray tubes externally with inhibited R.P. oil. Block fans from rotation (Short Term only) Leave belts installed - Do not treat Fill gearboxes with R.P. oil (V.P.I.) Treat fan motors as small motors Check semi annually for diesel leakage or maintain 5 psig nitrogen pressure for one year Check semi annually R.P. oil in gear box and refill when required Discontinue monitoring after 1 year
Preservation of Fin-Fans for Minimum First Cost
Mothballing 6.1.3.4
Treat tubes internally as for Short Term Do not treat tubes externally Do not block fans Leave belts installed - Do not treat Treat gear boxes as for Short Term Treat fan motors as for Short Term Discontinue monitoring and maintenance
Preservation of Evaporate Coolers for Short Term or Long Term Mothballing A)
Cooling Tower with Plastic Downcomer -
Stop circulating system Drain basin Discontinue monitoring/maintenance
B)
Cooling Tower with Wooden Downcomer -
6.1.3.5
Add Algacide to basin and circulate water weekly to keep wood wet Consider removal of wood and drain basin (Long Term only) Check circulation system semi annually if water is circulated weekly Discontinue monitoring/maintenance after 1 year
Preservation of Evaporate Coolers for Minimum First Cost Mothballing -
Drain basin Do not remove plastic downcomer Remove wooden downcomer Discontinue maintenance General corrosion is expected and replacement of plastic downcomer and circulation system is likely
Table 8-A Heat Exchangers Mothballing Facility
Short Term
Long Term
Minimum First Cost
1.
Shell and Tube
-
Remove free water Treat as pressure vessels
-
Same as short term
-
Same as short term
Monitoring/ Maintenance
-
Same as pressure vessels
-
Same as short term
-
None
Recommissioning concerns
-
None
-
None
-
Pitting and/or general corrosion expected Tube replacement likely
2.
Fin-Fans a)
Tubes - Internal
-
Treat as 1)
-
Same as short term
-
Same as short term
b)
Tubes - External
-
None
-
Spray with inhibited R.P. oil (offshore only)
-
None
c)
Fan-Blades
-
Block fan from rotation
-
None
-
None
d)
Belts
-
None
-
None
-
None
Table 8-B Heat Exchangers Mothballing Facility
Short Term
Long Term
Minimum First Cost
Fin-Fans e)
Gear Box
-
Fill with R.P. oil (V.P.I.)
-
Same as short term
-
Same as short term
f)
Fan Motor
-
Treat as small motors
-
Same as short term
-
Same as short term
-
Semi annually for diesel leakage or Maintain 5 psig pressure for one year Check R.O. oil in gear box and refill Discontinue monitoring after 1 year
-
Same as short term
-
None
None
-
None
-
Fitting and/or general corrosion expected Replacement of tubes, fans, belts and motors likely
Monitoring/ Maintenance
Recommissioning concerns
-
-
Table 8-C Heat Exchangers Mothballing Facility
3.
Short Term
Long Term
Minimum First Cost
Cooling Tower Wooden Downcomer (Combinaire)
-
Add algacide and circulate weekly to keep wood wet
-
-
Same as long term
-
Consider removal of wood Drain basin
Cooling Tower Plastic Down comers
-
Drain basin
-
Drain basic
-
Drain basin
-
None
-
None
-
General corrosion expected
Evaporate Coolers a)
b)
Recommissioning concerns
7
ROTATING EQUIPMENT 7.1
Basic Considerations 7.1.1
General A)
7.1.2
The mothballing procedures for the preservation and maintenance of rotating equipment are dependent mainly on the size and type of equipment and the recommissioning period specified. Mothballing procedures will involve one of the following: 1)
Preservation of the entire rotating equipment in situ.
2)
Preservation of the rotating equipment in situ, but some vulnerable components to be removed and stored in a controlled atmosphere.
3)
Preservation of entire rotating equipment indoors in a controlled atmosphere.
Types of Rotating Equipment The following equipment is considered rotating equipment: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
7.1.3
Centrifugal Pumps Reciprocating Pumps Submersible Pumps Chemical Injection Pumps/Metering Pumps Centrifugal Compressors Reciprocating Compressors Gas Turbines Steam Turbines Gear Boxes Hydraulic Variable Speed Couplings Torque Convertors Tank Mixers Diesel Engine Emergency Diesel Generators
Some Specific Concerns and Considerations 1)
Shutdown of a plant or facility with rotating equipment is complex and demanding, and a mistake in the selection of the mothball procedure can result in the deterioration of expensive equipment.
2)
Idle equipment is very sensitive to internal and external corrosion and will deteriorate quickly if not satisfactorily preserved. The exclusion of moisture is essential to avoid pitting and oxidation of critical components such as gear teeth, bearing journals, shaft seals, blading, etc.
3)
Sand ingress into the close clearance components in rotating equipment, such as shaft labyrinths, bearings and seals, is another concern. Equipment must be properly sealed during the mothball period to prevent ingress of sand and or sand dust since this could cause seizure/damage.
4)
Large, centrifugal type rotating equipment, such as the injection pumps, process gas compressors, gas and steam turbine drivers, sometimes has slender and heavy shafts. These shafts are susceptible to "creep" (a permanent or semi-permanent bend or sag in the shaft) if the shaft of an idle machine is not turned periodically. For this reason, equipment manufacturers advise that spare rotors for such machinery be turned periodically (monthly to quarterly) or that the rotor be stored vertically if turning is no t possible. Note: If a rotor is to be turned while in its casing, the journal bearings must have a lubricant film; otherwise damage will occur. Rust preventive oil provides adequate lubrication. Because of leakage across the clearance between shaft and bearing/seal, periodic rotor rotation assures that the rotor maintains a complete protective coating of rust preventative when the casing can only be partly filled with rust preventative.
5)
A large number of high horsepower pumps which are subject to rotor sag are installed at Saudi Aramco. For example, 4000 HP (3000 psig operating pressure) multi-stage horizontal centrifugal pumps (Ingersoll-Rand and Sulzer) are installed at the desalting facilities. Pumps (Weir) of similar design are used for waterinjection and are even larger in capacity than brine injection pumps (15,000 HP -3000 psig operating pressure). The cartridge type design of these pumps is such that shaft, impellers, diffusors, head flange, bearing brackets and seals can be easily removed from the pump barrel and the unit stored in a vertical position. It is recommended the cartridge be removed as one unit from the pump barrel and stored indoors when a long layup period is required.
If stored indoors, such rotors should be coated with a thick coating of rust preventative (solvent cut-back type) and then hung vertically. Storage outdoors (possibly adjacent to the machine) is also an approved method. In this case, the rotor can be immersed in a vertical position within a container fabricated from large diameter steel pipe filled with rust preventative oil. 6)
7.1.4
Frequent starting of gas turbines will shorten turbine rotor and stator/blading life. Therefore, mothballing procedures should avoid firing of the turbine.
Mothball Media Selection Considerations 1)
In general, machinery's internal surfaces can be coated with rust preventatives by circulating the oil through the equipment and/or oil piping by using the lube/seal oil pumps. Another method is sealing of the openings on the casing and filling to the top with rust preservative, and, if necessary, draining to shaft height should leakage across the shaft/bearing be a concern.
2)
All internal spaces of rotating equipment should be filled with either an inert gas, (N2) rust preventative film, or an inert fluid to prevent corrosion damage to the machine surfaces and internal walls of the equipment.
3)
See Appendix E & G for available rust preventatives.
4)
Most rust preventative solvents (cut-back type) exposed to the atmosphere will last for a maximum of one year. Thus, if shutdown is to go beyond this period, rust preventatives must be reapplied and coating repairs may be needed.
5)
ISO 46 for heavier grade oil with the addition of Vaprotec UPI should be used as rust preventative oils in large systems. Deisel Engine oil CD SAE 30 or SAE 40 grades are suitable in smaller systems.
6)
Critical components such as bearing and journals, crankcase, coupling, reservoir, cylinders of rotating equipment are best protected by rust preventatives. Journal sections which are monitored by proximity vibration displacement probes should also be protected by rust preventative to avoid pitting corrosion of these highly polished surfaces.
7)
The recommended media for protection of machinery internals for lay-up of mothballed equipment are listed in Table 9.
7.1.5
Mothballing Options The following options are considered for the preservation of rotating equipment: 1.
Storage The ideal mothballing procedure for most rotating equipment would be to store the equipment in a suitable warehouse where dry air with a relative humidity of maximum 40% can be maintained. Unfortunately, this is not particularly feasible for large equipment. Rotating equipment which is relatively small and useable elsewhere should be removed from the processing facility and stored in a warehouse under controlled conditions such as dry air. This option is only considered viable for skid mounted proportioning pumps, diesel engines, submersible pumps and rotating equipment where economics favor indoor indoo r storing for long term mothballing. A disadvantage of this type of storage is the risk of damage during dismantling and transport of the equipment to storage.
2.
Insitu When complete processing facilities, such as onshore and especially offshore GOSP's are to be mothballed, first consideration must be given as to whether the equipment can be effectively protected in situ. Preservation of rotating equipment in situ has the following advantages: -
-
-
No dismantling costs No indoor storing costs No identification problems. Equipment stored indoors may not be easily traced after 5 - 10 years lay-up if improperly tagged. Use of the same lay-up medium in certain cases, a pump or compressor, located in a processing facility is an integral part of the process equipment and its associated piping, and will be subjected to the same selected lay-up medium, such as instrument air purge or nitrogen blanket. No special equipment required. Removal of these pumps or compressors may require specially made drop-in spools for
-
replacing the removed removed pumps or compressors. Considerable time may also be required to realign these machines to their drivers during the snap back period. Snap-back period for recommissioning will be relatively small.
The disadvantages are: -
-
-
-
7.1.5
Large rotors may loose their straightness if they cannot be rotated periodically. If a spare rotor is available and has been properly stored, the snap back period will not be jeopardized. Bent rotors may need to be returned to the manufacturer for rework and this could impact on snap back period if no spare rotor is available. Replacement of components such as bearings and seals will generally be required after mothballing is terminated. However, these can be easily replaced and spares should be available from stock. Equipment left in situ is exposed to the ambient atmosphere and protection of internals by using greases, rust preventative oils, vapor phase inhibitors, or other long-lasting preservatives is required. If the rotor is not removed, the shaft/casing gaps at the bearing housings should be sealed with a silicone caulk, and taped so that the casing can be filled completely with rust preventative media. This option provides full protection of rotating equipment which does not need to have their rotors periodically turned during a long shutdown period; however, periodic inspection and maintenance still may be required.
Preparation Procedures Prior to Shutdown The following steps shall be followed prior to undertaking any preservative action to the rotating equipment: 1.
Stop all rotating equipment and insure the facility is not operating.
2.
If applicable, de-energize and lock out all breakers in the 34.5 kV, 13.8 kV, 4.16 kV, 2.4 kV switchgears and 480 V MCC's for electric motors and emergency diesel generators. Note: Some breakers will remain remain in service to provide electrical power to fire-water pump motors and/or air compressors.
Refer to Electrical Equipment, Chapter VIII for detailed Mothballing Procedures and Guidelines for Electric Motors and Emergency Diesel Generators.
7.3
3.
Flush and drain all rotating equipment when applicable.
4.
Purge with nitrogen if hydro-carbon gases are present or are believed to be present.
5.
Isolate pumps or compressors from line (if required).
6.
Remove and preserve coupling or spacer between pump/compressor and driver to facilitate rotating of rotor (if required).
7.
Properly tag and store spacer and/or coupling parts.
8.
Isolate gear box between pump/compressor and driver when applicable.
9.
Remove and preserve rotors along with seals and bearings (if required).
10.
Install end covers on casing openings if rotors have been removed.
11.
Seal ventilation openings.
12.
Fit turn bars on rotors rotors if rotors remain in case. Do not weld bars on rotor shaft.
13.
Provide electric electric motors with a warning that they are "Energized" or "De-energized" and provide other rotating equipment with warning when space heaters have been installed.
14.
For each piece of rotating equipment, prepare a complete complete listing of mothballed status and procedure as defined by Saudi Aramco General Instruction Manual GI Number 1000.250. (Appendix F)
Guidelines for Mothballing Specific Rotating Equipment 7.3.1
Centrifugal Pumps - Refer to TABLE 10 and Paragraph 7.1.3
7.3.2
Reciprocating Pumps - Refer to TABLE 10 7.3.2.1
General
Reciprocating pumps of various sizes are used by Saudi Aramco to pump slop-oil, sludge and similar products. Large units, such as 350 HP Wheatley pumps, are used in stripper service offshore. Some small size pumps are installed on portable skids. This makes transport to and from a storage warehouse convenient. 7.3.3
Submersible Pumps - Refer to TABLE 10 7.3.3.1
General Sumbersible pumps are only used in shallow water supply wells. Generally, water from these wells is less aggressive than water from deep water wells (Wasia and Biyadh formations). Remove submersible pumps from the wells and store in a warehouse using the following procedure. -
Carefully pull riser-columns and pump from the wells. Wind electric cable on a reel. Disassemble airline tubing and discard (low dollar value). Check the electric motor to determine if it is provided with a mercury seal.
Note: The motors of submersible pumps from Byron Jackson have a mercury shaft seal. Because spilled mercury presents a health hazard to servicing personnel, special steps are required to prevent spillage of mercury before the motor is laid horizontally. (See instruction manual of Byron Jackson.) -
-
Note: It is recommended services be obtained from Byron Jackson when pump and motor must be removed from well. This company has a service station InKingdom. Byron Jackson Services should also overhaul the pump and motor as required and prepare them for indoor storage. Disassemble pump submersible type from motor and disconnect cable from motor. Drain and clean pump and prepare for indoor storage. Store in vertical position. Drain all the water from balance chamber and pressurematic balance tube (be careful that the oil is not
-
7.3.4
drained) and plug the balance chamber. Clean the electric motor and prepare for indoor storage. Store the motor in a vertical position. Tag the pump and motor in such a way that they can be reassembled as one original unit.
Chemical Injection Pumps/Metering Pumps - Refer to TABLE 10 7.3.4.1
General In general, chemical injection pumps and metering pumps are small in size and capacity. Two options for the preservation of these pumps are presented-one for skid-mounted pumps and one for pumps permanently installed. Skid-mounted -
Store indoors. Drain and clean pump then lubricate all rotating or moving parts, including driver. Do not disconnect pump from driver and do not remove instrument or meters from the equipment. Store as one unit. Tag properly. Treat same as reciprocating pump.
Preserve in Situ (for Short Term) 7.3.5
Displace the chemicals in the injection lines with diesel oil and fill the chemical tanks with diesel. Fill the injection pumps with rust inhibiting oil. Do not remove the injection quills.
Centrifugal Compressors - Refer to TABLE 10 7.3.5.1
General All types of centrifugal compressors when preserved in situ for a long term period will require periodic maintenance. The rotor, if not turned periodically, will exhibit permanent sag. The rotor should be removed and stored indoors in a vertical position if possible. The rotor should also be placed in the original shipping canisters (if available) under a dry nitrogen blanket which will need to be turned periodically if mounted horizontally. Oxidation of the shaft, bearings,
blades and seals can be prevented by completely coating all metal surfaces with a rust preventive coating. 7.3.6
Reciprocating Compressor - Refer to TABLE 10 7.3.6.1
General Various large size reciprocating compressors are installed at Saudi Aramco facilities. It is recommended that compressors be left in situ and be protected internally and externally for short or long term mothball period. Storage of the complete unit indoors is not recommended or feasible.
7.3.7
Gas Turbines - Refer to TABLE 10 7.3.7.1
General Because removal of complete units for indoor storage is not physically possible, the equipment must be preserved in situ when long term mothballing is required. If the rotors cannot be turned periodically, it is recommended that the HP and LP rotors be removed and placed vertically in indoor storage in order to prevent rotor sag. Mothballing options are as follows: Option 1. Preserve in situ Short or Long Term -
-
Blank inlet and exhaust sections. Remove the load coupling and preserve indoors. Turn on the lube oil system on a monthly basis and rotate both the HP and LP shafts 1 1/4 or 2 1/2 turns each time by ratcheting or hand barring. Fill all oil systems to maximum levels with rust preventative oil. Circulate all oil systems in order to wet all system surfaces. Seal breathers and other openings to the oil systems. Over grease anti-friction bearings and linkages till fresh grease appears externally. Circulate preheated air.
Option 2 - Preserve in Situ - Rotor(s) removed and stored indoors
-
7.3.8
Remove rotor(s) from the gas turbine and store indoors in a vertical position preferably in a canister. Protect the machine internally and externally as recommended in Option 1. Use heater, dessicant on VPI fog, to keep moisture out of blocked turbine interior.
Steam Turbines 7.3.8.1
General Saudi Aramco operates various steam turbines (200 to 10,000 HP) as drivers. Store the small steam turbines in situ if these machines are to be mothballed for long periods and do not remove rotors. Large steam turbines should be left in situ. Removal of the rotor(s) depends on its sensitivity to sag and whether it can be turned periodically. Treat these large steam turbines as Centrifugal Compressors.
7.3.9
Gear Boxes 7.3.9.1
General Gearboxes are classified as (1) gears lubricated by oil in the case and (2) gears that have forced feed lubrication. The case should be completely filled with a rust preventive medium, and in order to prevent oil leakage, caulked and taped along the shaft and bearings. It is not necessary to turn the rotors.
7.3.10
Hydraulic Variable Speed Couplings 7.3.10.1
General Hydraulic variable speed couplings are mainly used for crude loading pumps and can vary in size and capacity from a few hundred horsepower to 14000 HP. This type of rotating equipment is very complicated and it is not recommended that any components be removed from these machines when short or long term mothballing is required.
Small hydraulic variable speed couplings can be stored in situ outdoors; however, large speed couplings should be preserved in situ. Draining and flushing of these pieces of equipment is recommended whether the equipment is stored ndoors or preserved in situ. Internal protection of this equipment shall be achieved by partly filling the case with R.P. Vaprotec. The recommended options is: Preserve in Situ 7.3.11
Disconnect hydraulic variable speed coupling from motor and pump. Drain and flush completely. Seal off all openings. Fill case partly with R.P. Vaprotec (See Appendix E)
Torque Convertors 7.3.11.1
General Torque convertors are generally installed between a start motor and a gas turbine train. Lay-up for torque convertors are practically the same as those for hydraulic variable speed couplings. It is not recommended that the start motor and gas turbine be disconnected from the torque convertors since reinstallation is a complicated procedure.
7.3.12
Tank Mixers Tank mixers should be left on layed-up storage tanks. Long term protection against oxidation and corrosion is very difficult; therefore, it is recommended these mixers be replaced when storage tanks are recommissioned. If needed, the storage tanks can also be used for quite some time without operating tank mixers.
7.3.14
Diesel Engines Diesel engines that are not used to drive emergency diesel generators, should be properly preserved or used elsewhere. Skid-mounted or truckmounted diesel engines can be preserved indoors or insitu for short or long term mothballing. For either short or long term mothballing, the procedures described for reciprocating compressors should be followed.
7.3.15
Emergency Diesel Generators
Emergency diesel generators for operating firewater pumps, airconditioning and navigation lights (offshore) should be left operable as standby units and maintenance should be performed per normal schedule.
Table 9-A Preservation Media For Machinery/Internals Mothball Term
Equipment Service
Centrifugal Pump Casing
Reciprocating Pumps Cylinders Crankcase
a)
Water
1)
R.P. Oil
1)
R.P. Oil
1)
R.P. Oil
b)
Hydrocarbon
1) 2)
R.P. Oil Crude
1)
R.P. Oil
1)
R.P. Oil
a)
Water
1)
R.P. Oil
1)
R.P. Oil
1)
R.P. Oil
b)
Hydrocarbon
1) 2)
R.P. Oil Crude
1)
R.P. Oil
1)
R.P. Oil
Short
Long
NOTES on Available Media: -
R.P. = Rust Preservation (Oil or Solvent Cutback Types) N2 = Nitrogen Diesel (Inhibited) or Crude Oil X = Not applicable
Table 9-B Preservation Media For Machinery/Internals Mothball Term
Equipment Service
a)
Water
b)
Hydrocarbon
a)
Water
b)
Hydrocarbon
Cylinders
Reciprocating Pumps Crankcase Pulsation Bottles
X
X
Centrifugal
X
X
Short 1)
R.P. Oil
1)
X
R.P. Oil
1)
X
R.P. Coating & Treat as Piping
1) 2)
X
R.P. Oil N2 X
Long 1)
R.P. Oil
1)
R.P. Oil
1)
Treat same as Recip. Compressor Short Term
1) 2)
R.P. Oil N2
Table 9-C Preservation Media For Machinery/Internals Mothball Term
Equipment Service
a)
Water
b)
Hydrocarbon
a)
Water
b)
Hydrocarbon
Steam Turbines
X
Gas Turbines
Gear Boxes and Hyd. Couplings
X
X
Short Treat same as Centrifugal Compressor Short Term X
1)
Seal + Preheated Preheated Air + Operate Oil System + Turn Monthly
1)
X
R.P. Oil
X
Long Treat same as Centrifugal Compressor Short Term
Treat same as Gas Turbine Short Term
1)
R.P. Oil
Table 10-A Rotating Equipment Mothballing Machinery Type
1)
Short Term
Long Term
Min. First Cost
Centrifugal Pumps a)
Submersible
-
Remove and use elsewhere
-
Same as short term
-
Same as short term
b)
Vertical Can
-
Leave in situ Do not turn Caulk and tape shaft/casing gaps Fill casing with R.P. Oil or grease See Appendix B Additional steps Install temporary cover over coupling area
-
Same as short term
-
Same as short term
-
c)
Horizontal Type Lesser Than 4,000 H.P.
-
Treat same as 1B
-
Same as short term
-
Same as short term
Greater Tan 4,000 H.P.
-
Leave in situ
-
-
Leave in situ
-
Turn shaft monthly Fill casing to shaft height with R.P. Oil Fill bearing housings to normal level with R.P. Oil Install temporary cover over coupling area See Appendix B
-
Remove rotor and store vertically Caulk and tape shaft/casing gaps
-
Do not turn
-
-
Fill casing and bearing housing fully with
-
Same as short term
-
Same as short term
-
Same as short term
-
Same as short term
-
Same as short term
Table 10-B Rotating Equipment Mothballing Machinery Type
2)
Short Term
Long Term
Min. First Cost
Centrifugal Compressors a)
Process Gas
-
Leave in situ Fill casing with N2 or fill casing to shaft height with R.P. Oil Operate lube/seal oil systems monthly Turn shaft monthly See Appendix B for additional steps
-
-
-
Remove and store if no manpower to turn shaft or to operate lube/seal oil systems Fill casing with R.P. Oil If rotor not removed, block in oil piping to bearings so can be filled with R.P. oil, turn shaft monthly See Appendix C for additional steps
-
Leave in situ Do not turn shaft/ casing gaps Fill casing and bearings with R.P. Oil
b)
Refrigeration
-
Same as 2(a) short term
-
Same as 2(a) short term
-
Same as 2(a) for minimum first cost
c)
Instrument Air
-
Leave in situ Operate lube/seal monthly See Appendix B for additional steps Purge casing with N2, dry air or fill casing to shaft height with R.P. Oil
-
Same as 2(a) for long term
-
Same as 2(a) for minimum first cost
-
Table 10-C Rotating Equipment Mothballing Machinery Type
3)
Gas Turbines
Short Term
-
Leave in situ Operate lube oil systems monthly Blind suction and discharge flanges install air pre-heater Turn shaft monthly See Appendix B for additional steps
Long Term
-
-
4)
Gears
-
Grease or fill bearing housing with R.P. Oil Fill casing to shaft height with R.P. Oil Leave in situ Turn shafts monthly See Appendix B for additional steps
-
Min. First Cost
If utilities or manpower are not available to operate lube system and turn shafts, remove and store rotors Block suction and discharge flanges and install air pre-heater whether rotor removed or not If motor not removed, block oil to bearings and turn shaft monthly See Appendix B for additional steps
-
Reove and store rotors, if can't seal shaft/ casings If can seal shaft/ casing, fill casing fully with R.P. Oil Do not turn rotors
-
-
Leave in situ Do not turn shaft Block in oil to bearings Block in suction and discharge flanges and install air pre-heater
Leave in situ Do not turn shaft Seal shaft/casing and completely with R.P. Oil
Table 10-D Rotating Equipment Mothballing Machinery Type
5)
Short Term
Long Term
Min. First Cost
Reciprocating Compressors a)
Utility Air
-
-
-
b)
Gas Lift
-
-
If instrument air required keep compressor in service, otherwise do not operate. If not operated, remove cyclinder suction valves and fill cylinder with R.P. Oil Turn shaft monthly Fill crank case with R.P. Oil. Seal off distance piece openings See Appendix V for additional steps
-
Leave in situ Remove suction valves and fill cylinder and crank shaft with R.P. Oil Turn shafts monthly See Appendix B for additional steps Seal off distance piece openings
-
-
-
Do not turn Remove cylinder suction valves and fill cylinder with R.P. Oil Fill crank case completely with R.P. Oil Seal off distance piece openings See Appendix B for additional steps
-
Remove piston and rod and store Do not rotate Remove suction valves and fill cylinder and crank case See Appendix B for additional steps
-
-
-
Leave in situ Do not turn shaft Remove cylinder suction valves and fill cylinder with R.P. Oil Seal off distance piece openings
Leave in situ Do not turn shaft Remove suction valves and fill cylinder with R.P. Oil. Fill crank case fully with R.P. Oil Seal off distance piece openings
Table 10-E Rotating Equipment Mothballing Machinery Type
6)
Reciprocating Pumps
Short Term
-
-
7)
Remove suction valves and fill cyclinder with R.P. Oil Turn shaft monthly See Appendix B for additional steps
Long Term
-
Min. First Cost
Remove suction valves and fill cylinder with R.P. Oil Fill crank case with R.P. Oil Do not turn shaft See Appendix B for additional steps
-
-
Leave in situ Do not turn shaft Fill seal casing/shaft gap and casing with R.P. Oil
-
Same as long term
-
Remove and store Fill seal shaft/casing and casing with R.P. Oil
-
Leave in situ Do not turn shaft Fill seal shaft/ casing and casing fully with R.P. Oil
-
-
Leave in situ Do not turn shaft Remove suction valves and fill cyclinder with R.P. Oil. Fill crank case fully with R.P. Oil
Steam Turbines a)
Lesser than 1,000 H.P.
-
Leave in situ Turn shaft monthly Fill casings and bearings with R.P. Oil to shaft height
b)
Greater than 1,000 H.P.
-
Leave in situ Operate lube system monthly cylinder and Fill casing with N 2 or fill partly with R.P.
-
NOTE: R.P.
=
Rust preservative oil with vapor phase inhibitor added. Note rust preservative oil should have viscosity of approximately 220 - 300 SSU at 1 00 deg F plus Vaprotec or SAE 30/SAE 40 Crankcase oil.
8
ELECTRICAL EQUIPMENT 8.1
Basic Considerations 8.1.1
General The mothballing guidelines for the preservation and maintenance of electrical equipment are dependent mainly on the size and type of equipment, the required mothballing term and the time required for recommissioning. Mothballing procedures will involve one of the following:
8.1.2
1)
Preservation of entire electrical equipment in situ.
2)
Preservation of entire electrical equipment indoors in a controlled atmosphere.
Types of Electrical Equipment The following equipment is considered electrical equipment: 1. 2. 3. 4. 5. 6. 7. 8. 9.
8.1.3
Transformers Motors Substations and Switchracks Cables Batteries and Battery Chargers Generator and Associated Facilities Instrument Power Supply Junction Boxes Conduit Systems Cable Trays Security Lights
Some Specific Concerns and Considerations 1.
Mothballing of electrical equipment, such as motors and transformers, is complex and demanding and a mistake in the selection of the mothball procedure can result in the deterioration of expensive equipment.
2.
Some electrical equipment, when idle, is very sensitive to internal and external corrosion and will deteriorate quickly if not satisfactorily preserved.
3.
The exclusion of moisture is essential to any protection program to avoid oxidation of critical components such as bearings, shaft seals and insulation material, etc.
8.1.4
4.
Sand ingress into the close clearance components in electric motors and/or junction boxes is also a concern.
5.
As in large centrifugal type rotating equipment, shafts of large motors are susceptible to "Creep", if not turned periodically.
6.
The majority of transformers, motors, and battery chargers can be preserved for Short or Long Term without recommissioning concern, providing the equipment remains energized.
7.
When mothballed at Min. First Cost in situ, electrical equipment will quickly deteriorate if electric power is switched off.
Mothballing Options The following options are considered for the preservation of electrical equipment which can be removed: 1)
Store transformers, motors, batteries, battery chargers and UPS inverters in a suitable warehouse. Unfortunately, this is not particularly feasible for large motors and transformers. Then the electrical power supply should be preserved only, for the following: a. b. c. d. e. f.
8.1.6
Plant incoming power transformers. 34.5 kV switchgear and transformers. 13.8 kV switchgear and transformers. 4.16 kV switchgear and transformers. 2.4 kV switchgear and transformers. 480 V control centers and lighting transformers and lighting panel boards.
General Procedures The following steps shall be followed prior to undertaking any preservative actions to the electrical equipment: 1) 2)
Stop all rotating equipment and insure the plant is not operating. De-energize all breakers in the 34.5 kV, 13.8 kV, 4.16 kV, 2.4 kV switchgears, 480 V MCC's and distribution/lighting panelboards. Note:
Some breakers will remain in service to provide electrical power to the equipment indicated in paragraph 10.1.5.
3)
8.1.7
General Electrical Preparation Procedures -
8.2
All de-nergized breakers should be padlocked and tagged, indicating that connected equipment has been mothballed.
De-energize equipment prior to mothballing. Clean equipment internally with air-hose. Clean and dry terminal housings, boxes and control cabinets. Clean, dry and tighten all power and control connections. Apply light coat of petroleum jelly on exposed terminals. Replace any damaged or missing parts and hardware. Repair or replace leaking cabinet door seals and junction box gaskets. Check doors and covers for tight fit. Tighten all loose hardware. Place silica gel in boxes, enclosures, housings and panels. Tighten and re-anchor loose conduits. Repaint corroded or damaged areas on equipment exterior. Repaint corroded conduit and junction boxes near the mothballed equipment. Energize space heaters. Energize equipment that is to remain in service during the mothballing period. Protect and seal all cable ends from weather and mechanical damage. Apply Denso or equivalent on junction box fasteners.
Guidelines and Recommendations for Mothballing Specific Electrical Equipment. 8.2.1
Transformers Short Term - Long Term - Min. First Cost -
Clean and dry insulators. Check operations of trips. Energize transformers which are required during mothballing period. Check oil level and fill. Repair seats and oil leaks. Test oil and record data. Add additional nitrogen, when applicable, to ensure pressure of 2 - 5 psig. Remove debris around transformers semi-annually. Check oil level and fill semi-annually. Repair leaks.
8.2.2
Replace silica gel (desiccant) semi-annually. Store transformers (Min. First Cost Mothballing) .
Motors Short Term - Long Term - Min. First Cost A.
Motors less than 600 V - 200 HP -
B.
Motors greater than 600 V - 200 HP -
8.2.3
Energize space heaters (if available) (Short Term - Long Term). Shut off power and leave in situ (Min. First Cost Mothballing only).
Energize space heaters. Block air-inlet. Use space heater. Install space heater ammeter (if not already available). Shut off power and leave in situ (Min. First Cost Mothballing only). Check oil level in bearing housing semi-annually. Check operation of space heater semi-annually. Replace silica gel (desiccant) semi-annually. Rotate periodically.
Substations and Switchracks Short Term - Long Term - Min. First Cost -
-
Deenergize any part of switchgear or rack that will not be used during the mothball period. Wrap and seal current and potential transformers which will not be used or store transformers (Min. First Cost only). Clean and grease fuse clips with contact lubricating grease (SAMS No. 14-800-125). Place petroleum jelly on any movable or rusting part, such as: wheels, contacts, trip and cranking mechanism and disconnect fingers. Padlock all breakers, which will not be used, in "OFF" position. Tag all padlocked breakers indicating that connected equipment has been mothballed. Check switchgear/rack and building heating system. Place silica gel or desiccant inside cubicles which are not equipped with space heaters (Short and Long Term only).
-
-
If available, activate space heater (Short and Long Term only). Energize and tag breakers which are required for activating space heaters. Do not activate space heaters when equipment is mothballed at Min. First Cost. Indoor (Short and Long Term only) Seal any open holes in switchgear cabinets, especially in the
floor. -
Energize switchgear and building heating system. Outdoor (Short and Long Term only) Remove and tag all protective relays of breakers which will not be used and store indoors. Energize switchgear of rack space heaters. Tarpaulin switchgear of racks, but allow air ventilation at
bottom. Guidelines for Monitoring/Maintenance (Short and Long Term only) Three Months: -
Remove debris around outdoor switchgear/rack. Ascertain operating of space heaters and heating system. Ascertain operating of breakers providing power to equipment that are kept energized during the mothballing period.
Six Months: -
Replace silica gel inside cubicles.
Two Years: 8.2.4
Test and calibrate relays that are still in service. Clean main bus and breaker contacts that are still in service.
Cables Short Term - Long Term - Min. First Cost -
8.2.5
Deenergize all cables which are not used during mothballing.
Batteries - Battery Chargers - Inverters Short Term - Long Term A.
Batteries (Lead-Acid Type)
-
Clean battery terminals and apply light coat of nonoxidizing grease. Clean outside of battery cases with baking soda solution. Wipe off any acid spills. Apply light coat of petroleum jelly to battery rack hardware.
Units in service -
Check proper electrolyte level and density. Measure and record individual cell voltages.
Units not in service B.
Drain electrolyte and store. Store battery.
Battery Chargers -
Keep energized if batteries remain in service and if A/C is on and properly maintained. De-energize if batteries do not remain in service and
store. C.
Inverters -
Shut down.
Guidelines for Maintenance Three Months: 8.2.6
Check electrolyte level and density of batteries in service. Ascertain operating of battery charger. Check charge rate.
Batteries - Battery Chargers - Inverters Minimum First Cost -
8.2.7
Disconnect batteries and chargers and leave. Shut down inverters. Discontinue maintenance.
Generators and Associated Facilities
Short Term - Long Term - Min. First Cost (Exciters - Relays - Regulators) -
Energize space heaters (Short and Long Term only). Leave in situ, but do not activate space heaters (Min. First Cost only).
Guidelines for Maintenance (Short and Long Term only) Three Months: 8.2.8
Remove debris around equipment. Ascertain operating of space heaters. Check tarpaulin. Rotate periodically.
Instrument Power Supply Short Term - Long Term - Min. First Cost -
8.2.9
Do not keep power on unless A/C is on (Short and Long Term). Abandon and discontinue monitoring (Min. First Cost only).
Junction Boxes - Conduit Systems - Cable Trays Short Term - Long Term -
8.2.10
Remove dirt from box fasteners. Apply Denso or equivalent on box fasteners. Check semi-annually if Denso is to be reapplied.
Junction Boxes - Conduit Systems - Cable Trays Minimum First Cost -
8.2.11
Do not apply Denso on box fasteners. Abandon.
Security and Perimeter Fence Lights Short Term - Long Term A.
Offshore:
B.
Onshore: -
8.2.12
Keep energized. Continue monitoring/maintenance.
Keep energized. Continue monitoring/maintenance.
Security and Perimeter Fence Lights Minimum First Cost A.
Offshore: -
B.
Keep energized. Continue monitoring/maintenance.
Onshore: -
De-energize all outdoor lighting circuit breakers and abandon. Discontinue monitoring/maintenance.
Table 13-A Electric Equipment Mothballing Equipment
1)
2
Short Term
Min. First Cost
Transformers (Cathodic Protection Rectifiers) a)
Less than 600V
-
Energize (follow same procedure as normal operation)
-
Same as short term
-
Leave in situ energized
b)
Greater than 600V
-
Energize (follow same procedure as normal operation)
-
Same as short term
-
Leave in situ energized
Motors a)
Less than 600V (lesser than 250 HP
-
Energize with space heaters (if available)
-
Same as short term
-
Shut off and leave in situ
b)
Greater than 600V (greater than 250 HP)
-
Energize with space heaters (mandatory) Block air-inlet Install space heater ammeter (if not already available Rotate periodically
-
Same as short term
-
Shut off and leave in situ
If available activate space heater
-
Same as short term
-
Leave in situ but do not activate space heaters
-
3)
Long Term
Substations and Switchracks a)
Less than 600V
b)
Greater than 600V
-
Table 13-B Electric Equipment Mothballing Equipment
4)
Cables
5)
Batteries
Short Term
Long Term
Min. First Cost
-
Proect (seal) all cable ends from weather and mechanical damage
-
Same as short term
-
Same as short term
a)
Chargers
-
Keep energized if AC is on and properly maintained
-
Same as short term
-
Abandon
b)
Inverter
-
Shut down
-
Shutdown
-
Shutdown
Generator and Associated Facilities (Exciters-Relays-
-
Energize with space heaters Rotate periodically
-
Same as short term
-
Leave in situ but do not activate space heaters
7)
Instrument Power Supply
-
Keep power on if AC is on
-
Same as short term
-
Abandon
8)
Junction Boxes Conduit (Systems Cables Trays)
-
Apply Denso or equivalent on box fasteners
-
Same as short term
-
Abandon
9)
Security Lights
6)
-
a)
Offshore
-
Keep energized
-
Keep energized
-
Keep energized
b)
Onshore
-
Keep energized
-
Keep energized
-
Abandon
9
AIR CONDITIONING SYSTEMS Air conditioning will often be left in operation during short term mothballing to prevent instrumentation degradation. Window Units Remove from window or wall openings and seal openings with plywood and tape. No special precautions are required for the unit, but removal will improve the building sealing and reduce the temptation for unauthorized removal/use. Control Air Handling Systems A.
Packaged units -- Disconnect electrical supplys, seal off the outside air inlet and leave in place.
B.
Split systems -- Disconnect electrical supplys, seal off outside air inlet and drain freon (return to storage). Mothball components (i.e. compressor, motor) as specified equipment.
Table 14 Air Conditioning Systems Mothballing Facility
1)
2)
Window Type
Short Term
-
Remove and seal openings with plywood and tape If control rooms are provided with window type A.C., leave in place and operate
-
Disconnect electrical Seal air openings Leave in place
-
Long Term
-
Same as short term
Min. First Cost
-
Remove and seal openings with plywood and tape Control rooms included
Central Systems a)
b)
Packaged
Split Systems
-
-
Same as short term
-
Same as short term
Disconnect electrical Seal air openings Drain freon (return to storage) Treat component as specific equipment using nitrogen purge
-
Same as short term
-
Same as short term
Monitoring/ Maintenance
-
Semi annually pressure check
-
Same as short term
-
None
Recommissioning/ concerns
-
None
-
None
-
Large packaged units may require replacement
10
FLARE SYSTEMS Flare systems should be isolated from the flare tip and the in-plant portion mothballed as in-plant piping. (Relief systems should remain in service where plant vessels/piping contain hydrocarbon gas or liquid). Ground flare tips should be covered to prevent the accumulation of rainwater. Bottom, lowpoint drains should be left open for ground and elevated flares to drain firewater.
Table 15 Flare Systems Mothballing Facility
1)
Ground Flares
Short Term
-
2)
Elevated Flares
-
-
Long Term
Min. First Cost
Isolate flare system from flare tips Treat in-plant portion as in-plant piping and process vessels Cover flare tips Leave bottom low point drains open
-
Same as short term
-
Same as short term
Isolate flate stack from piping Treat-in plant portion as in-plant piping Relief system to remain in service where plant vessels-piping contain hydrocarbon gas or liquid Leave bottom low point drains open
-
Same as short term
-
Same as short term
Monitoring/ Maintenance
-
In-plant portion as in-plant piping
-
Same as short term
-
Same as short term
Recommissioning concerns
-
None
-
Replacement pilot tip likely
-
Extensive repair and/or replacement likely
11
BOILERS AND FIRED HEATERS 11.1
Basic considerations 11.1.1
General The mothballing guidelines for the preservation and maintenance of boilers and fired heaters are dependent on the required mothballing term and the recommissioning period specified. Guidelines of the various lay-up procedures for mothballing boilers in a steam generating plant are provided by the General Instruction Number 403.001. This General Instruction provides mothballing procedures for Short Term and Long Term mothballing only and does not provide guidelines for mothballing of boilers at Minimum First Cost. Lay-up procedures for mothballing fired heaters (furnaces) are g enerally less complex than for boilers, but common to the preservation of both are Stacks - Burners - Refractory and External Structure.
11.1.2
Some Specific Concerns and Considerations 1.
The main concern in shutting down and mothballing the fire-side of a boiler or fired heater is the potential for acid attack by condensed sulfur compounds on the refractory, its anchoring system and the casing plate. Since heater (furnace) casings operate below the acid dew point temperature, it may be assumed acid corrosion will occur. Thus, repairs may be needed at shutdown (Short and Long Term only).
2.
11.1.3
The extent of such repairs are dependent on the type of fuel fired and on the age of the unit. Fired heaters and fireboxes in high sulfur fuel service for over 10 - 12 years may need replacement of a majority of its refractory. (Short and Long Term). Newer units may need no repair work at all. (Short and Long Term).
Guidelines for Mothballing Boilers (Short Term and Long Term) -
Use dry storage procedures as outlined in paragraph C7.302 of "Care of Power Boilers, Section VII of the ASME Boiler and Pressure Vessel Code".
-
-
Follow Boiler - Lay-up Procedures as outlined in Saudi Aramco General Instruction Number 403.001 (where applicable). Cap stack(s) Remove and store burners Open all manways and if possible sidewall wall headers Install air eductors on the manway of the mud drum and steam drum Open firebox and manually clean down radiant tubes. Wash/neutralize tubes externally with carbonate solution if fuel contains greater than 0.5 wt % sulfur Decoke tubes internally Wash internally with soda ash if tubes are austenitic steel Protect tubes internally the same as connected piping Dry out refractory if tubes are externally washed (use burner) Optional: apply space heater Maintain normal paint schedule for the external structure
Monitoring/Maintenance -
Replace silica gel semi annually in mud drums and steam drums Check semi annually for diesel leakage (if applicable) Maintain 5 psig pressure on tubes (nitrogen - if applicable) Check space heater(s) if installed
Recommissioning Concerns 11.1.4
Short Term - None Long Term - Repair of refractory likely
Guidelines for Mothballing Boilers In general, the same procedures are recommended for mothballing boilers short term as are recommended for Long Term. But for minimum first cost mothballing note the following exceptions: -
Do not cap stack(s) Do not remove burners Do not wash tubes externally Do not decoke tubes internally if tubes are ferritic steel Discontinue normal paint schedule on external structure Discontinue monitoring and maintenance
Recommissioning Concerns -
General corrosion and acid attack to the refractory expected making replacement likely.
11.1.5
Some corrosion attack in boiler and tubes expected Repairs likely
Guidelines for Mothballing Fired Heaters (Short Term - Long Term) -
Cap stack(s) Remove and store burners and Seal openings Wash tubes externally with carbonate solution if fuel contains greater than 0.5 wt % sulfur Decoke tubes internally if necessary Wash internally with soda ash if tubes are austenitic steel Protect tubes internally as connected piping (Diesel - Nitrogen fuel gas) Dry out refractory if tubes are externally washed (use burner) Optional: apply space heater Maintain normal paint schedule for the external structure
Monitoring/Maintenance -
Check semi annually for diesel leakage (if applicable) Maintain 5 psig pressure on tubes (nitrogen - if applicable) Check space heater(s) if installed
Recommissioning Concerns 11.1.6
Short Term - None Long Term - Repair of refractory likely
Guidelines for Mothballing Fired Heaters (Minimum First Cost) In general the same procedures are recommended for Minimum First Cost mothballing of fired heaters as were recommended for Short and Long Term Mothballing, but with the following exceptions: -
Do not cap stack(s) Do not remove burners Do not wash tubes externally Do not decoke tubes internally if tubes are ferritic steel Do not use space heaters on refractory - Dry out only if tubes are externally washed Discontinue normal paint schedule on external structure Discontinue monitoring and maintenance
Recommissioning Concerns -
General corrosion and acid attack to the refractory expected.
-
Replacement of refractory and repairs or replacement of burners and tubes likely
Table 16-A Fired Heaters Mothballing Facility
Short Term
Long Term
Min. First Cost
1)
Stack
-
Cap
-
Cap
-
No action
2)
Burners
-
Remove and store Seal openings
-
Same as short term
-
No action Leave in situ
3)
Tubes a)
External
-
If more than 0.5 WT % sulfur, wash tubes
-
Same as short term
-
No action
b)
Internal Austenitic
-
Decoke if necessary Soda ash wash Protect as connected piping (diesel, N2 fuel gas)
-
Same as short term
-
Same as short term
c)
Internal Ferritic
-
Decoke if necessary Protect as connected piping (Diesel, N2 fuel gas)
-
Same as short term
-
Same as short term
Table 16-B Fired Heaters Mothballing Facility
4)
Refractory
Short Term
-
5)
Long Term
Min. First Cost
Dry out if tubes are externally washed (use burner) Optional: Space heater
-
Same as short term
-
Dry out if tubes are are externally washed
External Structure
-
Maintain normal paint schedule
-
Same as short term
-
No action
Monitoring/ Maintenance
-
Semi annually for diesel leakage Maintain 5 psig pressure on tubes Check space heater if installed
-
Same as short term
-
None
None
-
Repair of refractory likely
-
General corrosion and acid attach to the refractory expected Replacement likely
Recommissioning concerns
-
-
12
BUILDINGS 12.1
Basic Considerations 12.1.1
General Prior to mothballing, an economic analysis should be made of the options available for disposition of the excess building e.g. reuse within Saudi Aramco, reuse by a Non-Saudi Aramco Agency, mothball, abandon in place or demolish. Facilities Planning Department Department can assist in the economic analysis, including cost estimates for the options. Chapter 2 of this manual describes the philosophy of mothballing generally common to Saudi Aramco Aramco plant and buildings. buildings. In the case of plant, three levels of mothballing are relevant; short-term, long-term and minimum first cost. Due to the different nature of buildings, only one level of mothballing is applicable and is referred to in this chapter as simply 'mothballing".
12.1.2
Mothballing consideration will involve also the following: 1.
2. 3.
4.
12.2
Economic justification comparing costs of preservation, maintenance and recommissioning to the cost of demolision and rebuilding. Fire, safety and health hazards in keeping the building unoccupied. Effect of environment (wind, rain, humidity, heat and pollutants) and biological effects on the building and contents. The major natural environmental damage expected to mothballed buildings will come from water. If plumbing is correctly shut off and the building sealed against rain, no serious damages are likely. Security requirements. Vandalism can be a major problem in mothballed buildings. If the facility is securely sealed (and fenced where appropriate) the risk of vandalism is minimized.
Environmental considerations Temperature fluctuations, rain exposure, moisture absorption, chemical alteration of the masonry units and the mortar, elastic and plastic strains all acting in many combinations alter the appearance, weather tightness and strength of buildings. Some of the problems arise by wood-boring insects and wood-destroying fungi which proliferate in damp or dry conditions cond itions and cause the deterioration of plaster, gypsum board, insulation, carpets etc. besides wood. Chlorides, carbon dioxide, sulfur dioxide and oxides of nitrogen present in the atmosphere may also cause deterioration of the cement in concrete, carbonates in limestone, exposed iron in rebar, aluminum in conduits, metal metal siding and trim. Electrical wiring may be
damaged by rodents if they are permitted permitted to enter mothballed buildings. Entry of birds, bats and other animals will also cause damage to the building interior and contents. 12.3
12.4
Some specific concerns and considerations 12.3.1
The exclusion of water or high humidity (i.e. over 40%) is essential for any protection program to avoid corrosion and biological damage to the various components within the building. Heating and air conditioning systems, plumbing, sewage and fire water systems should all be drained of water completely and dried for mothballing.
12.3.2
Condensation of moisture under the roof and in other enclosed spaces should be mitigated by proper ventilation or by preventing moisture entry from outside into a dry building.
12.3.3
Excessive heat built up inside buildings should be avoided by blocking the sun entering the building bu ilding through glass windows.
12.3.4
All accumulations of flammable or combustible waste or rubbish and food should be removed from the building and the interior of the building should be disinfected.
12.3.5
Protection against the entry of poisonous sewer gas, animals, vermins and vandals should be made to avoid damage to the building and its contents during the mothballed period.
Preparation for mothballing 12.4.1
A thorough inspection of the building should be made by a qualified civil inspector for structural integrity, weather proofing, damage to the exterior and interior walls, roof, flooring, framing, insulation, doors, windows and ventilation outlets. An entomological survey should be done to determine the pest control treatment required prior to mothballing. Based on inspection and survey findings remedial work may be necessary to protect the building from the environmental considerations stated in paragraph 12.2.
12.4.2
12.5
A written procedure should be developed for each building listing the inventory, actions to be taken for preservation and protection, and the periodic monitoring responsibilities by inspection and security.
General procedures
The following actions should be completed to mothball buildings.
12.6
12.5.1
Clean the inside, remove all food, rubbish and combustible waste.
12.5.2
Shut off electricity, gas, and water supply.
12.5.3
Drain all water from supply, return and disposal lines including fire water lines, water heaters and storage tanks.
12.5.4
Dry utility water systems with compressed air.
12.5.5
Block off sewer outlets and seal.
12.5.6
Disconnect service to computer and communication systems at the switching station.
12.5.7
Block off all ventilation and other openings that permit air circulation. Install rodent proof screens and disinfect the entire building, p er entomological recommendations.
12.5.8
Board up all windows and exterior doors except one entrance for periodic monitoring inspection.
12.5.9
Ensure that the building is weatherproof and paint exterior walls if made of wood or metal siding, per normal maintenance schedule.
Mothballing associated equipment For mothballing air conditioning systems, utility systems, electical equipment, water tanks etc. which are associated with the building refer to the appropriate sections in the Saudi Aramco Mothball Manual.
12.7
Guidelines for monitoring/maintenance 12.7.1
Buildings which are mothballed require periodic inspection and security checks every 3 months for the first year and annualy thereafter.
12.7.2
Monitoring inspections should include both exterior and interior checks of the building and the external condition of the associated equipment. Proper safety precautions should be followed in entering mothballed buildings for inspection.
Table 18 Buildings Mothballing Facility
1)
Mothballing Actions
Exterior walls a)
Concrete, Brick, Stone
No action
b)
Wood, Metallic siding
Maintain normal paint schdule
2)
Weather proofing roof, windows, doors, other openings
Inspect and repair as necessary
3)
Ventilation systems
Block off to prevent air circulation inside building
4)
Utility water systems
Drain & dry with compressed air
5)
Sewer systems
Block sewer outlets & seal
6)
Air conditioning/Heating Systems
See Table 14
7)
Electrical systems including lighting, alarms emergency, power, elevators, etc.
a) b)
Shut off power See also Tables 13A and 13B
8)
Fire fighting equipment
a) b)
Leave in place Do not service
9)
Carpets
Disinfect
10)
Communication/computer equipment
Disconnect service
11)
Flamable & combustible materials, food, rubbish
a) b)
Remove from premises Shut off gas supply
12)
Exterior doors and windows
a)
Block off direct sun light entering the building Board up all windows and doors Leave one entrance for inspection
b) c) 13)
Protection against infestation, rodents, vermins and vandals
a) b) c) d)
14)
Security lighting and power
Disinfect interior Cover openings with insect proof Lock, barricade, secure all doors, windows and openings Install fence if necessary
Decide on a case by case basis
Monitoring/Maintenance
Check security, inspect inside & outside every 3 months for the first year and check annually thereafter.
Recommissioning concerns
None
CHAPTER VII MONITORING AND MAINTENANCE DURING MOTHBALLING Monitoring and maintenance of oilfield production processing and refining equipment depend on the objectives of mothballing. The objectives and factors influencing the mothball procedures are listed in Chapter II. It has been established that monitoring and maintenance are significant for Short Term Mothballing, some monitoring and maintenance will be required for Long Term Mothballing, and low or no maintenance costs are dictated for mothballing at Minimum First Cost. Availability and cost of maintenance personnel are important factors when equipment is mothballed for Short and Long Term. As explained in Chapter II, short-term lay-up of equipment and facilities idle less than six months requires little more than the normal turn-around precautions. Recommendations A Mothball Task force Team should be established for each facility in a specific area (field) to develop specific procedures for mothballing and recommissioning. This task force should be selected from experienced maintenance, engineering and operating personnel who will write the mothball procedures for the related equipment and facilities or pipe systems in their area of responsibility. Planning of the Mothball Procedures should be in accordance with the guidelines recommended in Chapter IV. It is recommended that "Inspection Guidelines for Mothballed Equipment" - Saudi Aramco Drawing No. DE-321351 be used as a check list for establishing the frequency of inspection and maintenance requirements during mothballing. In addition to the guidelines, as given in Chapter IV, it is strongly recommended that a special party audit team be established to verify mothballing records and results in all areas where facilities have been mothballed. This special audit team should report their findings directly to Saudi Aramco's Management periodically. This procedure will enable Saudi Aramco's Management to determine recommissioning terms for mothballed facilities as required.
APPENDIX A.
Extracts from the Exxon Refinery Mothballing Guide for Saudi Aramco.
B.
Recommended mothballing materials in SAMS.
C.
Product information.
D.
Boiler Lay-up Procedures - GI-403.001.
E.
Storage Preservation of Machinery - Issued by EXXON Chemical Company Baytown, Texas
APPENDIX A Extracts from the Exxon Refinery Mothballing Guide for Saudi Arabian Oil Company.
December 1982
Legend: X AA NA NO Note:
-
Applicable requirement As applicable to equipment Not applicable to equipment Not required or desired
TECTYL is a trade mark of Valvoline Oil Company, a division of Ashland Oil, Inc.
Utility Centrifugal Compressor Process Services Air/N2 ____________________________________________________________________________________________ High Horizontally Barrel Sundyne Speed Type Split Split Screw Axial Flow (vertical) Package Couplings 1)
All couplings (hubs, spacers, keys) spacers, keys) should be coated TECTYL 506 and store in warehouse
X
X
X
X
X
X
Casing 1)
Flush internals of heavy polymers
AA
AA
AA
AA
AA
NA
2)
Store stage diaphram assembly (or bladed carrier) in warehouse, clean and coatwith TECTYL 506
NO
X
NA
X
NO
NA
3)
Coat upper half of casing internals (which do not have casing vents) with TECTYL 930
X
X
X
X
NO
X
4a)
Install an oil filler pipe connection on casing at convenient location and such that filler pipe iletat slightly higher elevation than top of casing
X
X
X
X
X
X
4b)
If casing is separate of bearing housing, install an oil filler pipe also at bearing housings
X
X
X
X
X
X
5)
Blind suction and discharge nozzle flanges
X
X
X
X
X
X
6)
Blind the coupling housing flange
X
X
X
X
NA
X
7)
Blind or plug all casing openings, including those on bearing housing
X
X
X
X
X
X
Utility
Utility Centrifugal Compressor Process Services Air/N2 ____________________________________________________________________________________________ High Horizontally Barrel Sundyne Speed Type Split Split Screw Axial Flow (vertical) Package 8)
Fill compressor casing with TECTYL 930 using filler pipe per 4a,b (bearing, seal and coupling housing will fill up also). Vent trapped air from casing (where possible) to be sure all internals become coated with TECTYL 930
X
X
X
X
X
X
9)
When level in filler pipe indicates casing is full, screw on cap over filler mouth. Extend length of filler pipe as necessary to provide adequate volume for thermal expansion of TECTYL due to ambient temperature changes
X
X
X
X
X
X
10)
Coat all exposed sliding or machined surfaces, pins, studs and threaded connections on casing and its support pedestal with TECTYL 890
X
X
X
X
X
X
11)
For machines which have integral interstage coolers, the gas side will be filled with TECTYL 930 when the compressor casing is filled (as required in earlier step)
NA
NA
NA
NA
NA
X
12)
Integral gear boxes should also be filled completely with TECTYL 930 when the compressor casing is filled
NA
NA
X
NA
X
X
13)
Note - where shafts protrude through the casing, a teflon gasket should be installed (to prevent TECTYL leakage from the casing or rain leaking into casing)
NA
NA
NA
NA
X
NA
14)
Lube oil systems and reservoir mounted in machinery baseplate shall be protected per section covering "Lube & Seal Oil Systems"
AA
AA
AA
AA
NA
X
15)
Store inlet filter in warehouse
NA
NA
AA
AA
NA
X
Utility Centrifugal Compressor Process Services Air/N2 ____________________________________________________________________________________________ High Horizontally Barrel Sundyne Speed Type Split Split Screw Axial Flow (vertical) Package 16)
Blank off suction/discharge silencers aftercoating metal surfaces with TECTYL 890
NA
NA
X
AA
NA
AA
17)
Drain all casing cooling water jackets and plug. Leave valved drain connection cracked open slightly
NA
NA
AA
NA
NA
AA
18)
Protect all instrumentation and control panels as described in separate section covering Instrumentation
X
X
X
X
X
X
Reciprocating Compressor (excluding driver)
Service Process Gas Utility (Air/N 2)
1)
Remove the following: cylinder valves, unloaders, and rod packing. Coat with TECTYL 506 and store in warehouse.
X
X
2)
Blind opening at rod packing box.
X
X
3)
Blind compressor gas inlet and discharge casing connections, after filling cylinder and gas passages completely with TECTYL 930. (Allow some space for thermal expansion.)
X
X
4)
Do not clean or coat cylinder cooling passage, only flush with water, drain and air dry. Plug inlet cooling passage. (Leave low point drain cracked open and wire valve in this position (permits self draining of any atmospheric condensation).
X
X
5)
Blind opening at wiper ring adjacent to crosshead compartment.
X
X
6)
Fill crankcase and crosshead compartment completely with TECTYL 930. Install a valved vent (at high point if possible) to permit addition of TECTYL later if required.
X
X
7)
Blank off pulsation bottles and knock out drums after coating with TECTYL 930 (fill and then drain vessels).
X
X
8)
Coat intercooler/aftercooler gas passages (not water passages) with TECTYL 930 by filling and draining. Blank or plug all connections on these components. Keep low point drain valve on water side slightly open and wire valve in this position (water side need only be flushed and air dried).
X
X
9)
Fill all lubricators, lube pumps and filter on compressor frame with TECTYl 930. Plug all connections and vents.
X
X
10)
Coat flywheel with TECTYL 890 and cover with guard.
X
X
11)
Coat all exposed shafts and linkages with TECTYL 890. Cover crank shaft opening from compressor with tape.
X
X
12)
Remove all gear type couplings (hubs, spacers, keys) and pack of non-lube type couplings. Coat with TECTYL 506 and store in warehouse.
X
X
13)
Protect all instrumentation and control panels described in separate section covering Instrumentation.
X
X
Centrifugal Pumps
1a) 1b) 2) 3)
4)
5)
6)
7)
8a)
8b)
Flush pumps and drain casing. Neutralize step required
Hydrocarbon
Service Caustic Acid
Water
Horizontally Mounted (Vert.& Horiz.Split) Four Four Stages Stages
Vertical Mounted Single Multi0 Stage Stage
X
X X
X
X AA
X AA
X AA
X AA
Fresh water flush and air dry all cooling jackets
AA
AA
AA
AA
AA
AA
AA
Remove rotor and store in warehouse (coat with TECTYL 506 and mount vertically if possible to avoid need to rotate). Blind shaft openings on casing. Coat bearings & seals and store also.
AA
AA
AA
NO
X
NO
NO
Blind shaft openings on bearing housing if pump rotor is being stored.
AA
AA
AA
NO
AA
NO
NO
Fill pump casing with TECTYL 930,gas oil or glycol completely (leave room only for thermal expansion). Make sure stuffing box filled.
X
X
X
X
X
X
X
Plug cooling water jackets (bearing and stuffing box) but keep low point drain valve cracked open slightly.
AA
AA
AA
AA
AA
AA
AA
Coat space where shaft protrudes through bearing or stuffing box housings with TECTYL 890 and cover with tape. Insert tape between bearing shield (labyringth seal or deflector disc) and bearing cover. (See Attachment)
X
X
X
X
X
X
X
Remove gear type couplings(hubs, spacer keys) and coat with TECTYL 506. Store in warehouse.
AA
AA
AA
AA
AA
AA
AA
Remove disc pack of non-lube type coupling. Coat and store in warehouse
AA
AA
AA
AA
AA
AA
AA
Centrifugal Pumps
9)
Hydrocarbon
Service Caustic Acid
Water
Horizontally Mounted (Vert.& Horiz.Split) Four Four Stages Stages
Vertical Mounted Single Multi0 Stage Stage
Coat all exposed machine surfaces (shafts,pedestal support) with TECTYL 890
X
X
X
X
X
X
X
Fill bearing housings completely with all purpose EP-1 (grease) or heavy oil.
X
X
X
X
X
X
X
11a) Note: Pumps with rotors installed do not require rotation.
AA
AA
AA
X
AA
X
X
11b) Note: Mechanical seals and shaft packing are not being removed for pumps which have rotors installed.
AA
AA
AA
X
AA
X
X
12a) Blind suction and discharge pump flanges if pump casing will be filled with TECTYL 930.
AA
AA
NA
AA
AA
AA
AA
12b) Close pump suction and discharge block valves if pump casing and confined piping will be filled with gas oil.
AA
AA
NA
AA
AA
AA
AA
NA
AA
X
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
10)
12c)
Close pump suction and discharge block valves if pump casing and confined piping will be filled with antifreeze water solution.
12d) Keep pump suction and discharge block valves open if pump casing and confined piping will be purged with inert gas.
Positive Displacement Pumps
Reciprocating Proportioning Gear or Steam Motor or Injection Screw Driven Driven Type Type
1)
Flush and drain pump casing.
X
X
X
X
2)
Neutralize step required (if caustic or acid)
AA
AA
AA
AA
3)
Blind suction and disch. nozzles of pumps, liquid end.
X
X
X
X
4)
Remove and coat all valves and plate covers on liquid end with TECTYL 506 and store in warehouse.
X
X
X
X
Fill liquid end with TECTYL 930. Bar rotor or piston to coat all surfaces. Allow some space for thermal expansion of TECTYL.
X
X
X
X
Fill steam end with TECTYL 930. Bar piston and then drain TECTYL. Install steam end valves after coating with TECTYL 930.
X
NA
NA
NA
Coat internals of safety relief valves (which are integral with pump) with TECTYL 930.
NA
AA
AA
AA
Coat all joints where shaft protrudes from casings with TECTYL 890. Cover with tape. X
X X
Coat exposed piston rod, shafts, and machined parts with TECTYL 890.
X
X
X
X
Fill bearing housing and gear box with all purpose EP-1 grease.
NA
X
X
X
Fill packing lubricator with TECTYL 930 or all purpose EP-1 grease.
X
X
NA
NA
Remove gear type couplings (hubs, spacers and keys), cost with TECTYL 506 and store in warehouse Disc pack for non-lube type couplings should b e coated and stored in similar manner.
NA
AA
AA
AA
5)
6)
7) 8)
9) 10) 11) 12)
X
Gear Units (Separate Boxes)
1)
Applicable to all type Fans & Blower Compressors Generator Drives Special General Purpose Type Purpose Type
Loosen end covers containing shaft labyrinth oil seal from drive and driven end of gear box. Insert teflon rope packing around shafts and bearing to provide a positive shaft seal with gear box. Retighten end covers.
X
X
2)
Blind all oil supply and drain connections on box.
X
X
3)
Replace casing vent with valved pipe which extends just above casing top (serve as refiller).
X
X
Fill casing completely with TECTYL 930, making sure level is above gear elements and within the ne w filler piping. Leave space for thermal expansion and close filler valve.
X
X
5)
Coat all exposed shaft surfaces with TECTYL 890.
X
X
6)
Gear type couplings (spacer, keys, hubs) should be removed and stored in warehouse. Coat these parts with TECTYL 506. Disc pack for non-lube type couplings should be removed, coated with TECTYL 506 and stored in warehouse.
X
X
4)
Aircraft Derivative Type
Industrial Heavy Duty Type
Purge fuel system and gas passages. Drain all cooling water passages completely.
X
X
Remove gasifier section (aircraft derivative) clean, store in warehouse in container provided by manufacturer. Protect unit per manufacturer's instructions.
X
NA
Remove power turbine section (aircraft derivative) clean and store in warehouse. Protect with TECTYL 506. Protect per manufacturer instructions.
X
NA
Aircraft gasifier and power turbine rotors to be rotated per manufacturers instructions.
X
NA
Remove axial compressor rotor assembly (heavy duty type). Clean and coat with TECTYL 506 and store in warehouse per manufacturer's instructions.
NA
X
Remove power turbine rotor assembly (heavy duty type). Clean and coat with TECTYL 506 and place in warehouse per manufacturer's instructions.
NA
X
Heavy duty axial compressor and power turbine rotor assemblies to be rotated per manufacturer's instructions.
NA
X
Remove electronic overspeed protection and governors and store in warehouse per manufacturer's instructions.
X
X
9)
Coat fuel piping stop valves, spray nozzle, with TECTYL 930.
AA
X
10)
Blind flanges to oil (control, lube), air, fuel connections to gas turbine frame. Plug all vents.
X
X
Remove flame out sensors and store in warehouse per manufacturer's instructions. Plug openings.
X
X
Clean all stationary blading in axial compressor and turbine sections, inlet air box to axial compressor. Spray coat of TECTYL 930 to all these interior parts and surfaces. Isolate these sections by installing blind at inlet air box and exhaust gas duct scroll.
NA
X
Gas Turbines
1) 2)
3)
4) 5)
6)
7) 8)
11) 12)
13)
Blind sections of piping for control and lube oil between machine frame and oil reservoir.
14)
Protect accessories (gear boxes, oil system, startup drives, and couplings) per applicable attached instructions covering these types of equipment.
X
X
Remove inlet air filter cartridges and discard. Spray coating of TECTYL 930 to all latches, bolting, rollers, bearings. Protect any motor drives per instructions covering this specific item.
X
X
Coat all hydraulic cylinders internally with TECTYL 930 and block in.
X
X
15)
16)
Aircraft Derivative Type
Industrial Heavy Duty Type
Spray coat all adjustable nozzle control linkages with TECTYL 506. Grease all fittings with a vendor's recommended lubricant.
AA
X
Coat all machined surfaces on support pedestals and exposed bolting with TECTYL 890.
X
X
Low point drain valve for cooling passages should be cracked open slightly and valve handle tied to this position.
X
X
Protect all instrument and control panels as described in separate section covering these items.
X
X
Gas Turbines
17)
18) 19) 20)
Appendix B - Recommended Mothballing Materials In SAMS*
A.
LUBRICANTS 1.
Grease Compounds - Rust Inhibitive for pumps, air compressor crankcases and other applications where these procedures specify the use of - SAMS 26-007230/240* or
2.
TECTYL 506 for protection of exposed shafts and other machined surfaces SAMS 09-611-830
3.
Grease, Ball Valve, Cameron 31545-27-1, for lubrication of ball valves - SAMS 26-009-107
4.
Lubricant, Anti-seize, Anti-seize Compound for threaded fasteners - SAMS 26-011-067
5.
Ball Bearing Grease, for use in antifriction bearings of all types - SAMS 26-004-330
6.
Crank-case Oil, (Diesel Engine Oil), Use as R.P. oil - SAMS 26-005-130/140 Option 1: Add 5 percent Vaprotec to engine oil Option 2: Use turbine oil and add Vaprotec as R.P. oil (1 gram Vaprotec to 20 grams turbine oil)
7. B.
All purpose Grease EP1 - SAMS 26-004-130
OTHER MATERIALS: 1.
Paper, Greaseproof, for wrapping exposed shafts and other machined surfaces after they have been greased - SAMS 29-486-485
2.
Tape, for sealing openings, securing plastic protective films - SAMS 27-216-219
3.
Silica Gel, desiccant for protecting equipment from moisture - SAMS 27-580-824
*
SAMS - Saudi Aramco Material System. The SAMS stock numbers are shown.
Appendix C - Product Information
1.
TECTYL Products
2.
Denso Paste
TECTYL 506
A product of Valvoline Oil Company, Division of Ashland Oil, Inc. What it is TECTYL 506 is a solvent cutback, wax base, corrosion preventive compound. The dry film is firm, amber, waxy translucent. Benefits Easy Application TECTYL 506 is formulated for easy application by spray, dip or brush. Low Cost Protection TECTYL 506 is a one coat rust preventive. The thin film provides high coverage and low cost protection. Long Term Protection TECTYL 506 is excellent for long term protection of metallic surfaces against corrosion in either indoor or outdoor exposure and during domestic and international shipments. TECTYL 506 provides outstanding external protection of machinery,machine rolls, machine tools, automotive parts, dies,tubing,and spare parts. TECTYL 506 has a dielectric (insulating) strength of approximately 1000 volts per dry mil of film thickness and therefore protects electrical connections and helps prevent galvanic corrosion. Surface Preparation The maximum performance of TECTYL 506 can only be achieved when the metal surfaces to be protected are clean and dry. Remove dirt, rust, scaling paint and other contaminants before applying 506. Application Ensure uniform consistency prior to use. Continuous stirring or thinning is generally not required. If product thickens due to cold storage or loss of solvent during use, add only aliphatic mineral spirits and only if necessary to restore consistency. Apply at 10-30 deg C. (50-95 deg F.) by spray, dip or brush.
Coverage The theoretical coverage is 650 sq.ft/gallon (16 sq meters/liter) at the recommended dry film thickness of 1.3 mils (32.5 microns). Material losses during application will vary and must be considered when estimating job requirements. Removal TECTYL 506 can be removed if necessary with mineral spirits, or any similar petroleum solvent or vapor degreasing. TECTYL 506 can be removed from fabrics by normal dry cleaning procedures. Avoid using chlorinated or highly aromatic solvents when removing from painted surfaces as these solvents may adversely affect paint. Lab Data English
Metric
Flash, PMCC, Min.
100 deg F
37.8 deg C
Specific Gravity @ 60 F (15.6 C), Typical
0.88
0.88
Recommended Dry Film Thickness
1.3 mils
32.5 microns
Theoretical Coverage, Typical
650 sq ft/US Gallon
16 sq meters/Liter
Approximate Air Dry Time 77 F deg (25 deg C)
1 hour
1 hour
High Temperature Flow Point, Typical
300 deg F
149.5 deg C
Low Temperature Flexibility, Typical (90 bend.No flaking or cracking)
10 deg F
22.5 deg C
(A) *ASTM B-117 @ 1.3 mils. Typical (2x4x1/8 in.Polished Steel Panels)
2000 hours
-
(B) *DIN 50021 @ 32.5 microns, Typical (125x200mm. DIN 1623 Panels)
-
Accelerated Corrosion Tests: 5% Salt Spray (Hours)
* *
165
ASTM (American Society for Testing and Materials) DIN (Deutsche Industrie Norman)
CAUTION TECTYL 506 cures by solvent evaporation. If applied to the interior of an enclosed vessel adequate ventilation is required for cure and to ensure against formation of an explosive atmosphere. For further information, consult Technical Bulletin 173.
TECTYL 890
A product of Valvoline Oil Company, Division of Ashland Oil, Inc. What it is TECTYL 890 is a solvent cutback, asphaltic base corrosion preventive compound. The dry film is firm, black asphaltic type. Benefits Easy Application TECTYL 890 is formulated for easy application by spray or brush. Low Cost Protection TECTYL 890 is a single coat rust preventive. The film provides high coverage and lowcost protection. Long Term Protection TECTYL 890 is excellent for long term protection of metallic surfaces against corrosion in either indoor or outdoor exposure and during domestic and international shipments. TECTYL 890 provides outstanding outdoor protection. TECTYL 890 is primarily designed for the protection of non-precision parts such as exterior surfaces, nuts, bolts, large chains and cables. TECTYL 890 will not corrode brass, cadmium, zinc, magnesium, aluminum or steel. Surface Preparation The maximum performance of TECTYL 890 can only be achieved when the metal surfaces to be protected are clean and dry. Remove dirt, rust, scaling paint and other contaminants before applying TECTYL 890. Application Ensure uniform consistency prior to use. Continuous stirring or thinning is generally not required. If product thickens due to cold storage or loss of solvent during use, add only aliphatic mineral spirits and only if necessary to restore consistency. Apply at 5-30 deg C (40-95 deg F) by spray, dip or brush.
Coverage The theoretical coverage is 450 square feet per U.S. gallon (11 sq meters/liter) at the recommended dry film thickness of 2.6 mils (65 microns). Material losses during application will vary and must be considered when estimating job requirements. Removal TECTYL 890 can be removed if necessary with mineral spirits, or any similar petroleum solvent. TECTYL 890 can be removed from fabrics by normal dry cleaning procedures. Avoid using chlorinated or highly aromatic solvents when removing from painted surfaces as these solvents may adversely affect paint. Lab Data English
Metric
Flash, PMCC, Min.
100 deg F
37.8 deg C
Specific Gravity @ 60 F(15.6 C),Typical
0.92
0.92
Recommended Dry Film Thickness
2.6 mils
65 microns
Theoretical Coverage. Typical
450 sq ft/U.S. Gallon
11 sq.meters/Liter
Approximate Air Dry Time 77 deg F(25 deg C)
1.5 hour
1.5 hour
High Temperature Flow Point, minimum
175 deg F
79 deg C
Low Temperature Adhesion,Scratch Test, No Flanking at 0 deg F
Pass
Pass
Accelerated Corrosion Tests: 20% Salt Spray (Hours), Typical (A)
Fed.STD 791, Method 4001 @ 2.6 mils, Typical
600 hours
-
(B)
Weather-o-Meter @ 2.6 mils, typical
1,200 hours
-
*
ASTM (American Society for Testing and Materials) Applicable U.S. Military Specification; MIL-C-16173D, Grade 1, MIL-P-116 Preservative, Type P-1.
CAUTION TECTYL 890 cures by solvent evaporation. If applied to the interior of an enclosed vessel adequate ventilation is required for cure and to ensure against formation of an explosive atmosphere. For further information, consult Technical Bulletin 173.