12-MGDP-I-1025-0 (Spec for Sales Gas Metering

VECO Doc. No. 20298-01-EJ12-005 20298-01-EJ12-005 Project Title

MEHAR GAS DEVELOPMENT PROJECT Area

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TABLE OF CONTENTS 1.0

INTRODUCT INTRODUCTION................................ ION................................................. ................................... ................................... .................................. .........................3 ........3

1.1

General General ................................ .................................................. ................................... .................................. .................................. .................................. ......................3 .....3

1.2

Scope Scope ................................... .................................................... ................................... ................................... ................................... ................................... .....................3 ....3

1.3

Definition Definitions s ................................. ................................................... ................................... .................................. ................................... ............................... ................4 ...4

1.4

Abbrevia Abbreviations tions................. ................................... ................................... ................................... ................................... ................................... ............................4 ..........4

1.5

Environmental

1.6

Device Device Protection Protection .................................. ................................................... .................................. .................................. .................................. .......................6 ......6

2.0

CODES, REGULATIONS REGULATIONS AND STANDARDS STANDARDS ................. ........ .................. .................. .................. .................. .................. ...........6 ..6

2.1

General General ................................ .................................................. ................................... .................................. .................................. .................................. ......................6 .....6

2.2

Units Units of Measure Measurement ment ................................ ................................................. .................................. .................................. .................................. ..................7 .7

2.3

Order Order of Preceden Precedence ce .................................. .................................................... ................................... .................................. ..................................8 .................8

3.0

OVERALL OVERALL SCOPE............................. SCOPE.............................................. ................................... ................................... .................................. .........................8 ........8

3.1

Scope Scope of Supply Supply ................................. .................................................. ................................... ................................... ................................... .........................9 .......9

4.0

SPECIFICA SPECIFICATION.............. TION............................... .................................. .................................. .................................. .................................. .........................10 ........10

4.1

General General ................................ .................................................. ................................... .................................. .................................. .................................. ....................10 ...10

4.2

Pressure / Differential Pressure Transmitters ................... .......... ................... ................... ................... ................... ................ .......12 12

4.3

Temperatu Temperature re Transmitte Transmitters rs .................................. .................................................... .................................... .................................... .......................12 .....12

4.4

Gas Chromato Chromatograph....................... graph........................................ .................................. .................................. .................................. ............................12 ...........12

4.5

Dew Point Point Analyze Analyzerr ................................. .................................................. ................................... ................................... ...................................17 ..................17

4.6

Flow Computer Computer................. ................................... .................................... ................................... ................................... .................................... ......................18 ....18

4.7

Analyzer Analyzer Hou House se .................................. ................................................... .................................. .................................. .................................. ........................21 .......21

5.0

INSPECTIO INSPECTION N AN AND D TESTING TESTING ................................. .................................................. .................................. .................................. ....................21 ...21

6.0

CERTIFICA CERTIFICATION TION OF COMPLIAN COMPLIANCE CE .................................. ................................................... ................................... .........................22 .......22

7.0

SITE SERVICES SERVICES ................................... .................................................... ................................... ................................... ................................... ....................22 ..22

8.0

SPARE PARTS AND SPECIAL TOOLS......... TOOLS .................. .................. .................. .................. .................. .................. ................. ........ 22

9.0

TRAINING.....................................................................................................................22

10.0

Documenta Documentation tion ................................. ................................................... ................................... ................................... ................................... ......................23 .....23

Conditions................................................................................................5

ATTACHMENT 1: P&ID-Sales Gas Metering

C:\Documents C:\Documents and Settings\shaikhb\Desktop\Bahuddin\20 Settings\shaikhb\Desktop\Bahuddin\20298-01-EJ12-00 298-01-EJ12-005 5 Rev 0 Specification Sales Gas Metering (12.05.08).doc

VECO Doc. No. 20298-01-EJ12-005 Project Title


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INTRODUCTION

1.1

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PETRONAS CARIGALI (Pakistan) Ltd. (PCPL) is undertaking the development of Mehar Gas Field in Mehar Block (Block 2767-1) located in Sindh and Balochistan Provinces of Pakistan. PCPL intends to develop the Mehar Field by installing a Gathering System, Gas Processing Facility (GPF) and Product Storage & Loading Facilities. The field facilities will be developed in two phases, Phase-I and Phase-2. Phase-1 development will cater to 55 MMSCFD of gas productions and Phase-2 will cater to 80 MMSCFD of gas productions. The expected condensate production rate is 6600 BPD for Phase-I and 7000 BPD for Phase-2. From GPF, treated sales gas will be exported through a new pipeline to existing SSGCL/SNGPL gas pipeline. Stabilized condensate and produced LPG will be exported by road tankers. Mehar Block is located in the Kirthar Fold belt area, in the Middle Indus Basin. Mehar field is located about 190 km west of Sukkur and 400 km north of Karachi in Sindh province. The environment is arid and the terrain is mountainous. Mazarani gas field, operated by PPL is situated about 25 km to the north, while Zamzama gas field operated by BHP is situated about 70 km to the north of Mehar Field. Mehar field consists of Pab and Ranikot formations. The wells will be connected to the new GPF through a Gathering System. There will be a total of 8 wells (4 in Pab & 4 in Ranikot) in Phase-1 and 3 additional wells (2 in Pab & 1 in Ranikot), totaling 11, in Phase-2 of the Mehar field development. 1.2

Scope This specification covers the minimum technical requirements for the design, manufacture, testing and supply of Sales Gas Metering Package suitable for installation in MEHAR Gas Development Project. This specification shall not be considered all-inclusive. The VENDOR shall submit full technical details of its well-proven standard equipment, which meet the project requirements herein. Aspects of the requirements, which cannot meet, shall be identified and variances explained. The sales agreement for gas is not finalized at this stage. CONTRACTOR and VENDOR shall be fully responsible to incorporate changes that may be proposed by the potential buyer / Government regulation. CONTRACTOR shall be responsibly for compliance to Government regulation regarding sales gas.

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Compliance with the specification, codes and standards does not relieve the VENDOR of the responsibility for supplying equipment of proper design and construction, fully suitable for all specified operating conditions. The Sales Gas Metering Package with the Analyzers shall be complete, tested, precommissioned, and commissioned so that it shall ensure a trouble-free start-up and operations of the new facilities. 1.3

Definitions COMPANY

Petronas Carigali Pakistan Limited (PCPL) or any Third Party assigned by the COMPANY

ENGINEER

Party which carries all or part of the design, engineering of the PROJECT. VECO Engineering, Abu Dhabi is the ENGINEER.

EPCC CONTRACTOR

Party which carries out all or part of the design, engineering, procurement, construction, commissioning or management, of the PROJECT. EPCC CONTRACTOR includes his approved, MANUFACTURERS,

SUPPLIERS,

VENDORS

and

SUBCONTRACTORS. MANUFACTURER/

Party/ies, which manufacture and/or supply materials,

SUPPLIER/VENDOR

equipment and services to perform the duties as specified by the CONTRACTOR in the scope of supply.

PROJECT 1.4

MEHAR GAS DEVELOPMENT PROJECT

Abbreviations AGA

American Gas Association

API

American Petroleum Institute

ASME

American Society of Mechanical Engineers

ASTM

American Society for Testing and Materials




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FM

Factory Mutual

GC

Gas Chromatograph

GSA

Gas Sales Agreement

IEC

International Electrotechnical Commission

IEEE

Institute of Electrical and Electronics Engineers

IP

Institute of Petroleum

ISO

International Organization for Standardization

NFPA

National Fire Protection Association

UL

Underwriter’s Laboratory

WGM

Working Gas Mixture

Environmental Conditions Wellhead facilities, Gathering stations and GPF area has been tentatively selected at a location about 190 km west of Sukkur and 300 km north of Karachi in Sindh Province. The environment is arid the terrain is mountain. The Environmental conditions are: Maximum Ambient Temperature

: 55ºC

Minimum Ambient Temperature

: 0.5ºC

Wet bulb temperature (design)

: 30ºC

Relative humidity (max / nor /min)

: 90 / 65 / 20 %

Direction of prevailing wind

: From south to north

Wind Velocity (max / normal)

: Hold / 2.9 knots

Elevation above Mean Sea Level (GPF)

: 54m (Site-IV) / 56m (Site-l)

Average barometric pressure

: 1001.2 mbara (29.56 inches of Mercury)

Ice / Snow

: None

Seismic zone

: Zone 2B, upper moderate with ground acceleration of 0.2 (Hold)




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Annual rainfall min.

: 63.3 mm (year 2006)

Annual rainfall max.

: 139.9 mm (year 2005)

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Device Protection All instruments/ electrical equipment installed in hazardous area shall be certified as EEx‘i’ IIA / IIB, T3. EEx’d’ is acceptable if EEx‘i’ is not available or can not be provided. All electrical installation materials shall be suitable and certified for use in this area classification. All field devices, installation material shall have weather protection to IP 65 as minimum.

2.0

CODES, REGULATIONS AND STANDARDS

2.1

General Codes, specifications and standards referred to within this specification, form a part of the requirements of this specification in a manner and to the extent specified within those codes and standards. Unless otherwise specified, the latest edition or revision to these codes specifications, and standards in force at the time of request for quotation and/or Purchase Order shall apply. No deviations from the Codes and Standards listed in this document will be allowed unless such deviations are clearly identified in the bids, with the reasoning. In addition, they must be approved in writing by COMPANY.

2.1.1

Codes and Standards AGA – 3/2000

:

Orifice metering of Natural Gas

AGA - 8

:

Compressibility factors of Natural Gas and other related Hydrocarbon gases.

ISO 9001:2000

:

Quality Management Systems- Requirements

ISO 10474 ASME Sec. VIII Div. 1

: :

Steel and Steel Products – Inspection Document Pressure Vessel

ASME Sec. IX

:

Welding and Bogging Qualification

ASME B 31.8

:

Gas Transmission and Distribution Piping System

ASTM 3588

:

BS 5345

:

Heat Value, Compressibility Factor and Relative Density of Gaseous Fuels Code of Practice for the Selection, Installation




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and Maintenance of Electrical Apparatus for use in Potentially Explosive Atmosphere

2.2

EN 50014 to 20

:

Electrical Apparatus for Potentially Explosive Atmosphere

IEC 60801

:

Electromagnetic Compatibility for Industrial Process Measurement & Control Equipment

IEC 60529

:

Classification for Degree of Protection Provided by Enclosures

IEC 60079

:

Electrical Apparatus for Explosive Gas Atmosphere

API RP 554

:

Process Instrumentation and Control

API RP 551

:

Process Measurements Instruments

Units of Measurement The Sales Gas Metering Package shall support any unit of measure where appropriate, however, the units of measurement to be used on this project shall be: Liquid Density: Flow Rate: Power, Duty:

: API and kg/m3 : m3 / hr, MMSCFD (gas), BPD (condensate), BWPD (Water) : kW

Heat Transfer Coefficient: Thermal Conductivity:

:

W / m2 K

:

W / m.K

Heat Capacity

:

kJ/ Kg °C

Viscosity:

:

cP

Kinematic Viscosity :

:

centistokes (cSt)

Area

:

m2

Length

:

Metre (m), Km, mm

Pressure

:

Bar (g), Bar (a), Psi (g)

Temperature

:

°F

Volume

:

m3

Pipe Diameter

:

mm




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Inch

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Mpa, Kg/cm2, Psi Kg

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Order of Precedence In case of conflicting requirements amongst any of the specified Standards, the Standard having the most stringent requirement shall be governing. In the event of contradictions, the order of precedence of various specifications shall be as follows: 1. 2. 3. 4. 5. 6. 7.

Government Legislations Gas Sales Agreement This Specification Project Specification COMPANY Standards International Codes and Standards; Vendor Standards.

In the event that CONTRACTOR is faced with conflicting information, Owner shall be contacted directly for a clarification. Owner’s interpretation shall be final. 3.0

OVERALL SCOPE VENDOR scope includes the design, engineering, manufacturing, assembly, FAT, supply, installation, testing, commissioning, training and documentation of the Sales Gas Metering Skid and Analyzers/Analyzer House. VENDOR overall scope shall include the following as a minimum: •

Supply of Metering Skid including as per section 3.1;

•

Metering Skid construction and assembly;

•

Supply of GC and Dew point analyzer including Analyzer house (this analyzers will be supplied by Vendor separate of metering skid);

•

Factory Acceptance Test (FAT) at VENDOR’S works;

•

Packing, transportation and delivery;

•

Site Acceptance Test (SAT);

•

Training to the plant operators & engineers (at VENDOR’S works or at site);

•

Supply of start-up and commissioning spares, special tools;




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Drawing and Documentation;

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Recommended spare part list for 2 years continuous operation.

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Scope of Supply The scope of supply for metering skid shall include three (03) metering runs (02 in continuous operation and one standby, in 2 X 100% configuration) with following details of each run. For additional information refer to P&ID, 12-MEGP-B-4028. •

One (1) upstream section with straight length of 18 D up to primary device with flow conditioner. The inlet side shall be flanged and the outlet side shall be welded to orifice fitting. Final requirement shall be base on AGA 3.

•

One (1) double chamber orifice fitting with 316 SS square edge orifice plate. The inlet side shall be welded to upstream section and the outlet side shall be flanged. The orifice assembly must include supply of plates, flanges, Stud Bolts, Nuts, Jack Screws, Gasket / Plate holder & Plugs;

•

One (1) downstream section having DN50 flanged connection for vent with straight length of 7 D up to outlet flange. Both sides shall be flanged;

•

The various accessories for senior orifice assemblies for operation under pressurized line condition. Ball valves, equalizer valves, bleeder valves, plate carrier, sealing and guide brackets etc. shall be as per VENDOR standard to suit not sour natural gas custody transfer requirement. Manual sampling point with isolation valve shall be provided. Refer to P&ID for valve sizes.

•

The installation, tubing, cabling and testing at site shall be carried out by the EPCC CONTRACTOR. The following instrumentations (but not limited) shall be provided and shall form part of the metering skid: 1. Two (2) Flow Indicating Transmitters (high and low range-pay) and One (1) Flow Indicating Transmitter (high range – check), for each run shall be provided. Transmitter ranges for high range shall be 0-2500 mm H2O and 0-500 mm H2O for low range. (Total of 9 FITs) 2. One (1) Pressure Indicating Transmitter and Pressure Gauge on each run. 3. One (1) Temperature Indicating Transmitter, One (1) Temperature Gauge and one (1) Thermowell for transmitter calibration on each run. 4. Two (2) Densitometer for each meter run if not provided by GC.

•

One (1) Flow Control Valve

•

Six (6) Motor Operated Valves

•

Automatic Sampling facilities in the inlet manifold

•

One (1) flow computer for each meter run to be installed on a cabinet panel.




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The supervisory flow computer shall be supplied with all necessary configuration software required. The supervisory flow computer shall form part of gas flow metering package. Supervisory flow computer location is in the control room. The configuration software shall run on Microsoft Windows XP; The supervisory flow computer shall communicate to the PMCS via serial link. A high availability supervisory computer with RAID 5, redundant hard disk as minimum.

•

Dedicated PC shall be provided with software installed such as Kelton, Flo cal or better;

•

Two (2) GC (1-working, 1 standby) and One (1) Dew point Analyzer, separate from Sales gas metering skid shall be supplied in Analyzer house. F&G Detection for the Analyzer house shall be provided. Preferred GC manufacturer in Daniel Industries.

•

Master Meter for proving.

•

Calibration tools for Analyzers and metering package.

•

Any validation and calibration software required for the flow computers.

4.0

SPECIFICATION

4.1

General The intent of this section is to describe the minimum acceptance parameters for the design, manufacture and supply of sales gas metering systems. Unless otherwise specified the enclosure Ingress Protection of the metering system transmitters (pressure, differential pressure and temperature), located in field, shall be at least IP65 as per IEC 60529. The junction boxes shall be in 316SS and cable trays shall be hot dip galvanized. The painting colour of Junction Box, cable trays etc shall be RAL 9010. The actual gas flow rate shall be measured by means of a 316SS square edge orifice plate installed in a double chamber senior orifice fitting of a meter-run. All shall be in accordance with AGA-3 and AGA-8 for custody transfer measurement unless otherwise specified in the GSA. The double chamber orifice fitting shall permit orifice plate replacement with line under pressure and flowing condition. Orifice diameter shall be calculated for square edge orifice with flange taps (½” NPT). Redundant flow computers shall be provided interfaces with GC, Moisture Analyzer, Control System and Field instruments. 230 VAC power supply shall be for GC, Dew point analyzer and flow computer.




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VENDOR shall use volumetric as well as Gross Calorific value calculations of the sales gas based on standard conditions of 60ºF and 14.73 psi as per AGA 3. The unit of measurement for volumetric calculations would be (1) standard cubic foot. The units of volume and calorific value for billing purpose would be MCF and MMBtu respectively. Flow computer software shall be in compliance with AGA 3 and AGA 8 unless otherwise specified in the GSA. 4.1.1

Meter Tubes The meter tube (18D) at the inlet of the orifice assembly, the meter tube (7D) at the outlet of the meter assembly, shall be designed as per AGA 3.

4.1.2

Pipe Material

:

ASTM A106 Gr. B, Seamless

Size & Thickness

:

DN150 NB, SCH. 80

End Connections

:

Flanged

Material

:

ASTM A 105 N

Size

:

DN150 Weld Neck

Rating / Face

:

CL600, RF

Finish

:

Smooth to 125 AARH (as per ASME B 16.5)

Bolt Material

:

ASTM A 193 B7

Nut Material

:

ASTM A 194 Gr. 2H

Down stream length

:

7D (D is the nominal diameter of the line)

Upstream length

:

18 D

Minimum Straight Lengths

Thermowell connection shall be 2" flanged and located as close as possible to the meter tube discharge flange. However the installation of the thermowell in the metering tube shall not affect the accuracy of the meter. 4.1.3

Basis of Sizing and Accuracy VENDOR shall provide calculations for all orifice plates. Calculations shall be in accordance with AGA-3, based on "beta" close to but not exceeding 0.6. The normal flow rate of the orifice meter shall be between 60 and 80 percent of the meter flow capacity. The anticipated maximum and minimum flow rate shall be 95 and 30 percent of meter flow capacity, respectively.




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The meter run uncertainty should be +/- 1% of mass flow rate @ 95% confidence level. Uncertainty calculation shall be submitted to COMPANY for review and approval. Switching between high range and low range differential pressure as the flow fluctuates shall be automatic. The thickness of the orifice shall be 6 mm (0.236”) for pipelines for DN150 line. The normal differential pressure range for flow metering orifice plate shall be 0 to 2500 mm-H2O. If this normal range is not practical, the standard range shall be 0 to 500 mm H2O, 0 to 5000 mm H20. VENDOR shall size the orifice plates as per process data sheet. All calculations shall be submitted to COMPANY for approval. 4.1.4

Sampling System Gas samples are required to determine gas composition, relative density and BTU content. Samples shall be collected at least once a month using automatic gas samplers. Minimum 3 samples of 500 cc are needed. Additional samples if required shall be advised by the COMPANY. Sample collection control system shall be by time based or by flow proportional mode selectable by the Operator. The sample rates or volume shall be unaffected by variances in pipeline or sample pressures or temperatures. Constant pressure sample cylinders shall be used. Manual sample points shall also provided in the metering skid with isolation valves. Samples shall be collected in bottles for analysis in a laboratory.

4.2

Pressure / Differential Pressure Transmitters For detail specification refers Doc # 12-MGDP-I-1024, Specification for General Instruments.

4.3

Temperature Transmitters For detail specification refers Doc # 12-MGDP-I-1024, Specification for General Instruments. Wake frequency analysis for thermowell shall be submitted to COMPANY for review and approval.

4.4

Gas Chromatograph The GC shall be used to give continuous quantitative composition analysis of natural gas from a process stream. The analysis is normally limited to the following main components and concentration:




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CONCENTRATION RANGE IN MOLE % (DRY BASIS-VAPOR)

H2S

0.0014

CO2

2.1761

Nitrogen

5.4281

Methane

77.7527

Ethane

5.6500

Propane

3.0980

Iso-butane

0.9214

Normal-butane

1.5551

Iso-pentane

0.7753

Normal-pentane

0.7460

Mcyclopentane

0.0992

n-Hexane

0.8204

Benzene

0.0628

Cyclohexane

0.1155

n-Heptane

0.4064

3-Mhexane

0.0857

Toluene

0.0637

n-Octane

0.1590

E-Benzene

0.0039

p-Xylene

0.0194

o-Xylene

0.0069

n-Nonane’s and heavier

0.0377

Notes: 1. The H2S content may increase to 35 ppm (wt) and shall be considered in the design. 2. The CO 2 content may increase to 5% mole in the future and design shall be considered in this aspect. The GC shall quantify the concentrations of the main components in the gas composition, for the purpose of gas accounting, calculation of calorific value and reference density in fiscal applications. The gas composition shall also be used for check of gas quality conformity with gas quality specifications defined by commercial gas agreements, and as a base for calculation of the operating density. The calculation of the operating density will normally be handled by the flow computers using live input values of the gas composition from the gas chromatograph. For this purpose serial interface shall be provided to the Flow Computer.




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Calculation of flow weighted average composition will normally be handled by the fiscal measurement computer system. The concentration given in mole % shall be converted to mass % for such calculations. The analytical results shall be traceable regarding sample point, time and date, calibration gas cylinder, calibration table, and time of last calibration. Recognized method for gas chromatograph analysis is ASTM 3588 and AGA 3. The daily and hourly averages of the sample gas as well as calibration gas analysis reports are required for at least 30 days. GC shall communicate via serial with PMCS to view some vital outputs i.e. BTU value, Wobbed Index and unnormalized mole %. Maintenance and calibration mode alarms of GC should be monitored on PMCS. GC shall be controlled from PMCS for Auto / manual operation. GC shall provide daily auto / manual generation of calibration reports. 4.4.1 Technical Requirements 4.4.1.1Sample Handling System The sample handling system shall collect a representative gas sample. The transport time through the sample handling system shall be less than 2 min. The sampling probe shall be installed so that a representative sample of the gas can be collected. The sampling probes shall be supplied with the analyzers. The distance to the nearest upstream disturbance, shall be at least 20 ID. Conditioning equipment is required to reduce pressure to a level suitable for the analyzer. Adequate protective filtering and coalescer have to be installed after the pressure reduction system to remove dirt and liquid entrainments if such contamination will be present. The temperature in all parts of the sample lines including sample conditioning equipment shall be kept at a temperature minimum 10 °C above the hydrocarbon dew point temperature. The dew point temperature shall be calculated by well recognized methods for every pressure level in the system. The temperature and pressure at critical points in the sampling system shall be indicated. Slope of at least 1:12 should be maintained along the sample line from the probe to the pressure reduction system in order to avoid liquid traps. The sampling probe should be designed so it is possible to be retracted under operating pressure by method accepted by the operator. All manually controlled shut off valves in the cabinets shall have a proper open/close indication. C:\Documents and Settings\shaikhb\Desktop\Bahuddin\20298-01-EJ12-005 Rev 0 Specification Sales Gas Metering (12.05.08).doc



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Waste samples from the analyzer shall be vented via a separate vent line specially designed in order to minimize influence from ambient conditions. Waste bypass gas from the cabinets can be vented to a common vent system. GC stream shall be selectable i.e the selection of calibration gas and sample gas for analysis of the stream. This shall be done by using tee or valve manifold. Calibration gases shall be supplied by Vendor, sufficient until final testing. 4.4.1.2 Analytical Unit The time required for a full analysis cycle shall be less than 10 min. The oven temperature shall be controlled to obtain required stability and accuracy of the analysis. The chromatograph shall use carrier gas in accordance with requirement given by the application. Pressure and flow rate of carrier gas shall be controlled with sufficient accuracy. Necessary equipment for safe operation in case of failure in carrier gas supply shall be installed if applicable. The chromatograph shall use thermal conductivity detector or equivalent. 4.4.1.3 Computer Unit Communications between the analytical unit and the computer unit should be according to the VENDOR’S standard protocol. The following functions shall all be available for the operator and should also be available from the supervisory computer: •

Start and stop the analysis cycle;

•

Change the alarm limits;

•

Acknowledge alarms;

•

Define and/or read component table, retention time retention time tolerance, response factor and valve switching;

•

Sequence, calibration frequency and WGM concentration;

•

Password protected program modifications;

•

Define and/or read time, peak height, peak area, peak start time, peak end time (for each component) and total area;

•

Select override analysis.

GC shall be configured that it does have an option to store at least 260 alarms and events.




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The computer unit shall have functions that give an alarm and inhibit the use of calibration tables containing response factors that are outside pre-set limits of acceptable values. The response factors for those components not present in the calibration gas shall either be manually entered or automatically calculated by using a mathematical relation to other components, i.e. calculate response factors for the hexane plus fraction from the response of pentanes or butanes. The chromatograms should be displayed in real time and also stored digitally with the possibility of later visual inspection. Start and stop of peak integration event marks and electronic baseline should be possible. A main report to the main network shall contain names of components, normalized mole % of each component rounded to the nearest 0,001 %. A quality control report for printouts and electronic transmission should contain information about retention time, peak height, peak width, peak area, response factor, and mole % before and after normalization. A control function in the software should give alarm if one or more components are missing from the report or that the sums of non-normalized values are outside pre-set limits. This alarm shall inhibit the transmission of potential erroneous results onto the main computer network. The following requirements for displaying items should be considered: •

Alarm status;

•

Historical analysis data for a single component in chart form;

•

Historical analysis data in report format, average, maximum and minimum values for each component and calculated values;

•

The last measured concentration value for each component and calculated values;

•

Real time chromatogram and valve status.

Alarm generation shall be standardized. Communication with the main metering computer should be via serial data link. 4.4.1.4 Calibration equipment The calibration gas bottles cabinet shall be electrically heated to prevent condensation. It should be possible to enter, store and change the composition of the calibration gas. The VENDOR of the WGM shall provide relevant documentation for the uncertainty calculations.




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4.4.1.5 Power Supply The chromatograph shall be powered by an uninterruptable power supply (240 VAC). Back-up facilities in each chromatograph shall additionally ensure that its data is not lost under any circumstances. 4.5

Dew Point Analyzer On-line Dew Point Analyzers shall monitor process gas and hydrocarbon liquid for water content. Sample stream composition and conditions shall be shown on Instrument Data Sheets. The moisture analyzer shall have a high sensitivity and shall not be affected by the presence of olefins. The analyzer and all equipment shall be suitable for use in the electrical area classification as shown on Instrument Data Sheets. Moisture Analyzer shall consist of but not limited to the following: •

Sensor (Thin Films Aluminum Oxide);

•

Analyzer indicator to indicate the water content;

•

Interconnecting cable.

The analyzer shall be provided with automatic switching for sample sensor selection and a manual switch for range and calibration selection. The analyzer shall provide an isolated DC output current signal of 4-20 mA for each stream to the flow computer. The output signal shall be linearly proportional to the ranges as specified on the data sheets. Interconnecting cable between sample probes and analyzer shall be provided. Analyzer shall be equipped with self-moisture generator. The input of Moisture Analyzer shall be communicated to control system and it should be used for the re-normalization of gas composition with moisture content as per ASTM standard. Dew Point Analyzer shall have the following Service Parameters; •

Accuracy shall be + 3.6 ºF;

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Power supply shall be 240VAC;

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Daily auto-calibration feature.




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4.6

Flow Computer

4.6.1

Hardware Requirements

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Flow computer shall be provided and able to handle differential pressure inputs for flow under process conditions, temperature, pressure and molecular weight. Flow computer will be in a cabinet located in the marshalling cabinet room. Flow computer hardware and software calculation blocks for flow computing shall be certified as suitable for use in custody transfer application by independent certification body e.g. NMI or PTB. Differential pressure (high and low range pressure), temperature and pressure values are acquired by the flow computer as 4-20 mA signals. The overall uncertainty of the metered standard volume flow rate, calculated in accordance with AGA 3/2000, shall not exceed ±1% (of mass flowrate) over the full operating range. Gas composition and molecular weight are acquired by flow computer via RS 485 physical interface MODBUS RTU protocol to Gas Chromatograph. Flow computer shall be provided with an internal printer and suitable interface. The flow computer shall also be able to provide as a minimum the following: •

RS 485 MODBUS RTU serial interface or Ethernet communication to control system;

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Four 4 - 20 mA isolated analogue signal outputs for compensated volume flow rate, mass flow rate, temperature and pressure as repeat signal for others;

•

Flow computer should also give two digital output signals for flow computer healthy status, flow computer fault status.

The flow computer shall be supplied with dedicated supervisory computer and all necessary configuration software required. The configuration software shall run on Microsoft Windows XP or latest. 4.6.2

Accessibility Levels The flow computer will have at least 2 access levels: •

Random access (engineering level);

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Restricted access (operator level).

The random access must be protected by means of a hardware switch-off facility and gives special access to the following data: •

Engineering units;

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Scaling factors;

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Correction factors;




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Calibration factors;

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Programming;

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Constants;

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The switch-off facility must be inside the computer housing.

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The restricted access level gives only access to the various displayed values such as:

4.6.3

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Differential pressure;

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Pressure;

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Temperature;

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Corrected flow rate;

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Mol % N2;

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Mol % CO2 etc.;

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Molecular weight;

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Accumulative corrected quantity;

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All data where a change of data does not affect the accumulated quantity.

Display The LCD type display presents alphanumeric data in at least 2 lines with a minimum of 16 characters each.

4.6.4

Key Pad The integrated key-pad serves the purpose of selecting the information to be displayed and of entering the alphanumeric values of data as described above in "Accessibility levels" Section.

4.6.5

Memory Back-up No data shall be lost including the totaled values, by an external power supply failure.

4.6.6

Software Requirements

4.6.7

Input Conditioning The input signals, for flow computer, from the differential pressure transmitters shall be linearised by the flow computer.

4.6.8

Selection of Flow Inputs Where two differential pressure transmitters shall be used, the selection of the low or high flow range transmitter shall be done automatically base on the flow rate. At the end of the low flow range of the transmitter for low flow, the computer switches over to the transmitter for high range by increasing flow. The reverse sequence is followed on decreasing flow.




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Computation The actual compensated gas flow must be calculated at reference conditions 60ºF at 14.73 psi absolute and in accordance with AGA-3 / 2000.

4.6.10 Error Handling Input errors (transmitter failure) must be displayed on the display and will activate the flow computer trouble alarm output. System errors shall be handled in the same way. Below an output of 10% for a period of up to 4 minutes, an alarm will be generated. Also at an output above 100% the system will generate an alarm "out of limit" on the system display and via the digital output flow computer trouble. Also an alarm message will be printed on the printer. The flow computer shall also generate Flow Computer healthy indication. The start and end time of every error will be stored in the system memory. 4.6.11 Print Reports Flow computer shall be able to produce a print report on manual command. A print report consists of the following information: •

Year, Month, Day and Time;

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Total cumulative corrected quantity in MMSCF;

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Cumulative corrected quantity for the previous day in MMSCF.

And if an error or hold state has been detected in the previous day: •

Alarm or hold state numbers;

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Time when the error or hold state has been detected;

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Time when the end of error or hold state has been detected;

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Type of error or hold state;

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Corrected quantity during error conditions for the previous day in MMSCF as cumulative total from begin to end of error.

4.6.12 Operating Status The normal operating status is without an input or position frozen. For testing and for calibrating of the computers or field instruments several inputs or positions can be frozen from the key pad as following: •

Hold State 1 This hold state will be used for testing and/or calibration of the transmitters only. During the hold state 1 the input signals are frozen on the last value;




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Hold State 2 This hold state will be used only for testing and calibration of the flow computers themselves. During the time this hold state is activated the flow totalling will be blocked. After resetting this hold state the totalling starts again with the last totalized value before the hold state.

4.6.13 Power Supply Flow computer shall be powered by an uninterruptable power supply (240 VAC). Backup facilities in flow computer shall additionally ensure that fiscal figures are not lost under any circumstances. 4.7

Analyzer House The pre-engineered packaged analyzer system shall include the pre-fabricated shelter, sampling system, analyzers, ventilation, electrical services and other utilities. Preengineered shelters shall be supplied by a specialist system fabricator to offer the best option in terms of convenience, cost, system responsibility and final product quality. Analyzer shelter shall provide a controlled environment for the operation and maintenance of the analyzer packages and shall protect the analyzers against extreme ambient conditions. Pre-engineered shelters shall be shipped with analyzers installed and all systems (air conditioners, ventilators, purge system, lighting & power supply systems) in place and tested before shipment. The shelter floor shall be sealed to prevent the ingress of vapour or gas. Analyzer shelter shall be large enough to allow adequate access and space for maintenance work and shall have two (2) exits located at opposite ends.

5.0

INSPECTION AND TESTING The COMPANY reserves the right for inspection of material, manufacturing process, testing, etc. Such inspection does not relieve the VENDOR of the responsibility of suitable design and workmanship. VENDOR shall submit a detailed Inspection and Test Plan (ITP) for approval with all activities and acceptance criteria. Sales Metering Skid shall be subjected to factory acceptance test. Following are the requirement for Factory Acceptance Test: •

Performance;




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Hydro Test;

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Review of NDTS;

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Review of Material and Calibration Certificate;

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Physical and Dimensions;

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Access for Individual Equipment for Maintenance Purpose.

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CERTIFICATION OF COMPLIANCE The gas flow meter skid package shall be certified by a suitable authority of the country of origin for AGA 3/2000 requirements.

7.0

SITE SERVICES The gas metering VENDOR / CONTRACTOR shall be responsible for the delivery, offloading and installation at site. VENDOR shall provide the services of an experienced ENGINEER to assist the CONTRACTOR for the following site activities:

8.0

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Mechanical completion: assistance for skid installation and site preliminary tests;

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Power-up, functional testing and commissioning;

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Site Acceptance Test.

SPARE PARTS AND SPECIAL TOOLS VENDOR shall supply special tools, if any required for configuration and maintenance of the system. The VENDOR shall include with the bid the recommended spare parts list as per the following and the material requisition:

9.0

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One (1) orifice plate similar to the one installed in the provided meter runs.

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Itemized recommended spare part list for start-up and commissioning;

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Itemized recommended spare parts list for two (2) years operation in SPIR forms.

TRAINING The scope shall include training for the operators, maintenance personnel & engineers as per the terms and conditions in the Purchase Order. Training shall cover the following areas as a minimum: •

Operation;




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Maintenance / Troubleshooting;

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Configuration.

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Training for the complete system shall be provided for COMPANY operations for 1 day and for maintenance / engineers for 3 days at VENDOR factory. For each trainee who will attend a training course, a copy of the complete training course, notes and drawing shall be provided to the COMPANY. The copies shall be retained by the trainees on completion of the training course and shall be the property of the COMPANY. 10.0

DOCUMENTATION Manuals provided shall be in English, written in a simple, clear and concise manner. A comprehensive set of manuals shall be supplied including but not limited to: •

General system description;

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Equipment specification;

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Application software documentation;

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Test and commissioning procedures;

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Meter Validation Manual

•

Operations Manual.

Vendor shall also comply the requirements of documentation specified in PCPL procedure CSP-03.


12-MGDP-I-1025-0 (Spec for Sales Gas Metering

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