INTRODUCTION
PROV PROVEN EN EGY EGYPT PTIAN IAN GAS GA S RESE RESERV RVES ES IS 62 TCF (AT (A T THE END OF 2003) 2003)
PROV PROVEN EN EGY EGYPT PTIAN IAN GAS GA S RESE RESERV RVES ES IS 62 TCF (AT (A T THE END OF 2003) 2003)
CUMULA CUMULATI TIVE VE GA GA S PROD PRODUCT UCTIO ION N IN EGY EGYPT PT IS IS TIL L 30/6/2 30/6/2003 003)) 13.5 TCF ( TILL
NATURA NATURA L GAS CONSU CONSUMP MPTI TION ON IN EGY EGYPT PT IS IS AROUND A ROUND 28 (A T THE 28.3 .3 B ILL ILLIO IONS NS CUB CUB IC ME METE TERS RS (AT END OF 2003) 2003) REPRESENTING REPRESENTING AB A B OUT 47 % OF THE PRIMAREY ENERGY CONSUMPTION IN THE COUNTRY
MAJOR GAS FIELDS IN EGYPT ARE : - ABU MADI - SHUKHEIR - BADREDDIN - ABU QIR
(EASTERN EUOROPE / FORMER SOVIET UNION)
NATURAL GAS CONSUMPTION - HOMES
(26%).
- COMMERCIAL APPLICATIONS (15%). - INDUSTRIAL APPLICATIONS(43%). - GENERATING ELECTRICITY (16%).
USE OF NATURAL GAS - FERTILIZERS - METHANOL - BLENDING AGENTS - PREMIUM GASOLINE - PETROCHEMICAL DERIVATIVES
NATURAL GAS INDUSTRIAL APPLICATION - PULP AND PAPER - METALS - CHEMICALS. - GLASS - CLAY - WASTE TREATMENT (INCENIRATOR) - FUEL IN VEHICLES - HEATING, COOLING, DEHUMIDIFICATION AND DRYING
NATURAL GAS COMPANIES IN EGYPT - BRITISH GAS (B.G) - B.P AMOCO. - ENI-AGIP. - SHELL. - RESOL - APACHE - INTERNATIONAL EGYPTIAN OIL COMPANY ( IEOC ) - EDISON
TYPES OF NATURAL GAS
- ASSOCIATED GAS (OIL WELL GAS) - NON-ASSOCIATED GAS (GAS WELL GAS) - GAS CONDENSATE
NATURAL GAS COMPOSITION
NATURAL GAS COMPONENTS
NATURAL GAS COMPONENTS PROPERTIES
PIPEL PIPEL INE SPECI SPECIFICA FICATION TIONS S
DEFINITIONS
Gas processin pro cessing g The separa separatio tion n of co nstitu nst itue ents from f rom na n atura tur al gas for th e purpose purpo se of making salable salable produc ts and also for treating treating the residue residu e gas to meet meet required specifi cations . Gas proce proc essing ssi ng plant p lant A p l ant an t w h i c h p r o c ess es s es n atu at u r al g as f o r r eco ec o v ery er y o f n atu at u r al gas liquids and some so metimes times other other substa subs tances nces such as sulfur . Gas-well Gas-well gas The gas gas produc pro duce ed or se s eparated parated at at surface sur face condit con dition ions s from fro m the full well well stream stream produced pr oduced fr om a gas reservoir. reservoir.
Gas-well s-well liquid liq uids s The liquid liqu id separated separated at at surface sur face condit con dition ions s from fr om the th e full ful l well stream stream produce produ ced d from a gas gas reservoir reservoir.. Natu Natural ral gas Gaseous seous form of pe p etroleum, consisting consi sting of mixtures mi xtures of h ydroca ydroc arbon gases. gases. As A s s o c i ated at ed g as Natural gas gas wh ich over lies and and is i n contact co ntact with crude oil in the t he rese reservoir rvoir.. Wet Wet gas g as Gas cont c onta aini ng water, water, or a gas gas whic w hich h ha h as not n ot been been de d ehydrate hyd rated. d.
Dry gas Gas whose water content has been reduced / removed by dehydration process. Lean gas Gas containing little or no hydrocarbon commercially recoverable as natural gas liquid pro duct. Rich gas Gas containing many hydrocarbons commercially recoverable as natural gas liquid product.
Synthetic gas (SNG) The gas product resulting from the gasification of coal and or gas liquids or heavier hydrocarbons. Acid gas The hydrogen sulfide and or carbon dioxi de contained in, or extracted from gas or other streams. Dew point The temperature at any given pressure at which liquid initially condenses fr om gas or vapor.
Raw gas Unprocessed gas or the inlet gas to gas processing plant. Sour gas Gas containing und esirable quantities of hydrogen sulfide, mercaptans, and or carbon dioxide. Sweet gas Gas which has no mo re than the maximum sulfur content defined by the specifications for the sales gas from a plant.
Water Dew point The temperature at which water vapor start to condense from a gas mixture. Hydrocarbon Dew point The temperature at which hydrocarbons start to condense from a gas mixture. Bubble point The temperature at any given pressure at which the first vapor form above a liq uid.
Hydrate A solid material resulting from the combination of a hydrocarbon with water under pressure. Desiccant A substance used in a dehydrator to remove water and moisture form gases or air. Dehydration The process of removing the water form gases or liquid.
Recovery That percent or fraction of a given component in the plant feed which is recovered as plant product. Light ends The low-boiling, easily evaporated co mponents of a hydrocarbon liquid mixture. Heavy ends The portion of a hydrocarbon mix ture having the highest boiling points. Distillation The process of separating a multiple components feed of differing boiling p oints into two or more products.
Absorber A tower or column that provides contact between natural gas being processed and a liqui d solvent. Absorption The operation in which one or more components in the gas phase are transferred to (absorbed into) a liquid solvent.
Adsorption The process by which gaseous components are adsorbed on solid s because of their molecular attraction to the solid surface.
Debutanizer A fractionator designed to separate butane (and more volatile components if present) from a hydrocarbon mi xture. Demethanizer A fractionator designed to separate methane (and more volatile components if present) from a hydrocarbon mi xture. Depropanizer A fractionator designed to separate propane (and more volatile components if present) from a hydrocarbon mi xture. Stripper A column wherein absorbed constituents are stripped from the absorption oil. The term is applicable to column s using a strip-ping medium, such as steam or gas.
Strippi ng factor An expression used to describe the degree of stripping. Mathematically, it is KV/L, the reciprocal of the absorption factor. Strippi ng medium As stated under " stripper" , the medium may be steam, gas, or other material that wi ll increase the driving force for strip-ping. Trayed co lumn A vessel wherein gas and liquid, or two partially miscible liquids, are contacted, usually concurrently on trays. Partial Pressure The pressure due to one of the several components in the gaseous mixture. Partial pressure of a gas in a perfect gaseous mixture is equal to its mole fraction in the mixture multiplied by total pressure.
COMPOSITION OF NATURAL GAS PRODUCTS COMPONENT CO2
H2S
N2
C1
C2
C3
IC4
NC4
IC5
IC5
C6+
NATURAL GAS
X
X
X
X
X
X
X
X
X
X
X
INERT GAS
X
ACID GAS
X
X
X X
LNG
X X X
NGL
X
X
X
X
X
X
LPG
X
X
X
X
X
X
X
X
X
X
CONDENSATE
X
NATURAL GAS TREATING
TYPES OF CONTAMINANTS -
AMMONIA (NH3).
-
HYDROGEN SULFIDE (H2S).
-
HYDROGEN CYANIDE (HCN).
-
CARBON DIOXIDE (CO2).
-
CARBONYL SULFIDE (COS).
-
CARBON DISULFIDE (CS2).
-
MERCAPTANS (RSH).
-
NITROGEN (N2).
-
WATER (H2O).
-
SULFER DIOXIDE (SO2).
REASONS FOR CONTAMINANT REMOVAL -
SAFETY CORROSION CONTROL GAS AND/OR LIQUID PRODUCT SPECIFICATIONS PREVENT FREEZE-OUT AT LOW TEMPERATURES DECREASE COMPRESSION COSTS FOAMING PREVENT POISONING OF CATALYSTS IN DOWNSTREAM FACILITIES MEET ENVIROMENTAL REQUIREMENTS
ACIDIC GASES SAFETY PROBLEMS HYDROGEN SULFIDE HYDROGEN SULFIDE IS A HIGHLY TOXIC GAS, AT VERY LOW CONCENTRATIONS IRRITATION OF THE EYES, NOSE, AND THROAT IS POSSIBLE. HYDROGEN SULFIDE IS A HIGHLY FLAMMABLE GAS AND WILL SUPPORT COMBUSTION IN AIR AT CONCENTRATIONS FROM 4.3 TO 46 VOLUME PERCENT.
ACIDIC GASES SAFETY PROBLEMS - CARBON DIOXIDE CARBON DIOXIDE WILL DISPLACE OXYGEN AND CAN CREATE AN OXYGEN-DEFICIENT ATMOSPHERE RESULTING IN SUFFOCATION. THE ATMOSPHERIC CONCENTRATION IMMEDIATELY HAZARDS TO LIFE IS 10 %(VOL.)
ACIDIC GASES CORROSION PROBLEMS
GAS STREAMS WITH HIGH H2S TO CO2 RATIOS ARE LESS CORROSIVE THAN THOSE HAVING LOW H2S TO CO2 RATIOS.
ACIDIC GASES CORROSION PROBLEMS
CORROSION IS STRONGLY A FUNCTION OF TEMPERATURE AND LIQUID VELOCITY.
ACIDIC GASES CORROSION PROBLEMS
REBOILER, RICH SIDE OF AMINE-AMINE EXCHANGER, STRIPPER OVHD CONDENSING LOOP TEND TO EXPERIENCE HIGH CORROSION RATES.
CORROSION CONTROL MINIMIZING - MAINTAINING THE LOWEST POSSIBLE REBOILER TEMPERATURE. - MINIMIZING SOLIDS IN THE SYSTEM. - KEEPING OXYGEN OUT OF THE SYSTEM BY PROVIDING A GAS BLANKET ON ALL STORAGE TANKS. - USING DIONIZED WATER FOR MAKE-UP WATER.
FOAMING PROBLEMS A SUDDEN INCREASE IN DIFFERENTIAL PRESSURE ACROSS A CONTACTOR OFTEN INDICATES SEVERE FOAMING
FOAMING RESULT IN REDUCING THE TREATING CAPACITY AND SWEETNING EFFECIENCY.
FOAMING REASONS -
SUSPENDED SOLIDS
-
ORGANIC ACIDS
-
CORROSION INHIBITOR
-
CONDENSED HYDROCARBONS
-
MAKE-UP WATER IMPURITIES
-
LUBE OIL
NATURAL GAS TREATING PLANT MATERIAL OF CONSTRUCTION TREATING PLANTS NORMALY USE CARBON STEEL AS THE PRINCIPAL MATERIAL OF CONSTRUCTION.
NATURAL GAS TREATING PLANT MATERIAL OF CONSTRUCTION STAINLESS STEEL 304, 316, OR 410 MAY BE USED IN THE FOLLOWING CRITICAL AREAS: -
REFLUX CONDENSER REBOILER TUBE BUNDLE RICH / LEAN EXCHANGER TUBES BOTTOM 5 TRAYS OF THE CONTACTOR AND TOP 5 TRAYS OF THE STRIPPER PIPING FROM RICH/LEAN EXCHANGER TO THE STRIPPER
GAS TREATMENT PROCESS SELECTION -
CONTAMINANTS TYPES AND CONCENTRATION. ACID GAS SPECIFICATIONS.
-
TREATED GAS SPECIFICATIONS.
-
VOLUME OF GAS TO BE PROCESSED.
-
TEMPERATURE AND PRESSURE AT WHICH SOUR GAS IS AVAILABLE.
-
HYDROCARBON COMPOSITION OF THE SOUR GAS.
-
LIQUID PRODUCT SPECIFICATIONS.
-
DISPOSAL OF BY-PRODUCTS CONSIDERED HAZARDOUS CHEMICALS.
-
OPERATING AND CAPITAL COST.
-
SELECTIVITY REQUIRED FOR ACID GAS REMOVAL.
CHEMICAL REACTION PROCESS (CHEMICAL SWEETNING)
CHEMICAL REACTION PROCESSES REMOVE THE H2S AND/OR CO2 FROM THE GAS STREAM BY CHEMICAL REACTION WITH A MATERIAL IN THE SOLVENT SOLUTION.
THE REACTION MAY BE REVERSIBLE OR IRREVERSBLE , THE REACTION IS REVERSED AT LOW PRESSURE AND HIGH TEMPERATURE.
CONTACTOR WORKS AT RELATIVELY HIGH PRESSURE AND RELATIVELY LOW TEMPERATURE, STRIPPER WORKS AT RELATIVELY LOW PRESSURE AND RELATIVELY HIGH TEMPERATURE.
CHEMICAL SWEETNING SOLVENT EQUEOUS ALKANOLAMINES
-
TRIETHANOL AMINE (TEA)
-
DIETHANOL AMINE (DEA)
-
MONOETHANOL AMINE (MEA)
-
DIISOPROPANOLAMINE (DIPA)
-
DIGLYCOL AMINE (DGA)
-
METHYLDIETHANOLAMINE (MDEA)
CHEMICAL SWEETNING PROCESS FLOW DIAGRAM
CHEMICAL SWEETNING MAIN PROCESS EQUIPMENT
INLET SEPARATOR THE INLET SEPARATOR SHOULD BE SIZED NOT ONLY ON THE BASIS OF INLET FLUID VOLUMES, BUT ALSO ON SURGE CAPACITY TO HANDLE SLUGS OF LIQUID HYDROCARBONS
FILTERATION FILTERATION IS ESSENTIAL TO REMOVE PARTICLES DOWN TO 5 MICRONS.
TWO STAGE OF FILTERATION MAY BE REQUIRED. THE FIRST STAGE, A CARTRIDGE-TYPE FILTER, TO REMOVE PARTICLES DOWN TO 10 MICRONS. THE SECOND STAGE OF FILTERATION TYPICALLY AN ACTIVATED CARBON FILTERS REMOVE HYDROCARBON AND OTHER CONTAMINANTS DOWN TO 5 MICRONS.
THE CARRYOVER OF CARBON FINES CAN BE CONTROLLED BY EITHER LOCATING A SECOND CARTRIDGE-TYPE FILTER IMMEDIATELY DOWNSTREAM OF THE CARBON FILTER OR USING A GRADED CARBON BED.
DURING PERIODS OF ANTIFOAM INJECTION, THE CARBON FILTER SHOULD BE TAKEN OUT OF SERVICE . CARBON WILL REMOVE MOST ANTIFOAMS AND WILL BE DEACTIVATED BY THEM.
FLASH TANK -
-
-
-
REDUCE ERROSION IN RICH / LEAN EXCHANGERS. MINIMIZE THE HYDROCARBON CONTENT IN THE ACID GAS. REDUCE THE VAPOR LOAD ON THE STRIPPER ALLOW USING THE OFF-GASES AS FUEL
RECLAIMER RECLAIMER IS USUALY REQUIRED FOR MEA AND DGA SYSTEMS TO REMOVE THE FOLLOWING: -
SUSPENDED SOLIDS ACIDS AND IRON COMPOUNDS
-
HEAT STABLE SALTS
-
DEGRADATION PRODUCTS
GAS TREATING USING CAUSTIC WASH (NAOH)
THE PROCESS EMPLOYS COUNTER-CURRENT CONTACTING OF THE GAS STREAM WITH A CAUSTIC SOLUTION IN A PACKED OR TRAYED COLUMN.
THE SPENT SOLUTION IS EITHER REGENERATED OR DISCARDED DEPENDING ON WHAT ACID COMPONENTS ARE PRESENT IN THE SOUR GAS.
IF ONLY MERCAPTANS ARE PRESENTED, THE CAUSTIC SOLUTION IS REGENERATED WITH STEAM
NAOH CAN BE USED TO TREAT NATURAL GAS STREAMS TO REMOVE CO2,CS2, H2S AND MERCAPTANS
H2S + 2 NAOH
NA2S + 2 H2O
CO2 + 2 NAOH
NA2CO3 +2H2O
RSH + NAOH
RSNA + H2O
PHYSICAL SOLVENT PROCESSES (PHYSICAL SWEETNING)
SOLVENTS USED IN PHYSICAL ABSORPTION - POLYETHYLENE GLYCOL DERIVATIVES - ANHYDROUS PROPYLENE CARBONATE
USES OF PHYSICAL SOLVENT PROCESSES -
THE PARTIAL PRESSURE OF THE ACID GASES IN THE FEED IS GREATER THAN 50 PSI
-
THE HEAVY HYDROCARBON CONCENTRATION IN THE FEED GAS IS LOW.
-
SELECTIVE REMOVAL OF H2S IS DESIRED
-
LITTLE OR NO ENERGY IS REQUIRED.
MAIN FEATURES OF PHYSICAL SWEETNING - PHYSICAL SOLVENT PROCESS IS CAPABLE OF SIMULTINEOUSLY DEHYDRATING AND SWEETNING THE GAS. - THE PROCESS OPERATE AT AMBIENT OR SUBAMBIENT TEMPERATURE. - THE SOLVENTS ARE RELATIVELY NONCORROSIVE SO CARBON STEEL CAN BE USED.
PHYSICAL SOLVENT PROCESS FLOW DIAGRAM
SWEETNING COMPINATION PROCESSES SULFINOL PROCESS SULFINOL PROCESS IS LICENSED BY SHELL COMPONY, IT IS USED TO REMOVE H2S, CO2, COS, CS2, MERCAPTANS AND POLYSULFIDES FROM NATURAL GAS. SULFINOL IS A MIXTURE OF SULFOLANE (PHYSICAL SOLVENTS), WATER AND EITHER DIPA OR MDEA (CHEMICAL SOLVENT)
GAS TREATING BY ADSORPTION
MOLECULAR SIEVE THE SIEVE BED CAN BE DESIGNED TO DEHYDRATE AND SWEETEN SIMULTANEOUSLY. PROCESS CYCLE TIMES ARE IN THE ORDER OF 6-8 HOURS TO OPERATE PROPERLY THE SIEVES MUST BE REGENERATED AT A TEMPERATURE CLOSE TO 600OF TO A LONG ENOUGH TIME TO REMOVE ALL ADSORBED MATERIALS, USUALY ONE HOUR OR MORE.
MOLECULAR SIEVE
MEMBRANE TECHNOLOGY
MEMBRANE TECHNOLOGY FOR CO2 REMOVAL MEMBRANES ARE SEMIPERMEABLE BARRIERS THAT SELECTIVELY SEPARATE SOME COMPOUNDS FROM OTHERS
MEMBRANE MATERIALS FOR CO2 REMOVAL -
CELLULOSE ACETATE
-
POLYIMIDES
-
POLYAMIDES
-
POLYSULFONE
-
POLYCARBONATES
-
POLYETHERIMIDE
MEMBRANE PERMEATION MEMBRANE DOESN’T WORK AS FILTER, WHERE SMALL MOLECULES ARE SEPARATED FROM THE LARGER ONES. INSTEAD, THEY OPERATE ON THE PRINCIPLE OF SOLUTION-DIFFUSION THROUGH A NON POROUS MEMBRANE. MEMBRANE SEPARATE BASED ON HOW WELL DIFFERENT COMPOUNDS DISSOLVE INTO THE MEMBRANE AND THEN DIFFUSE THROUGH IT. FAST GASES SUCH AS CO2, H2, HE, H2S, AND WATER VAPOR PERMEATE QUICKLY. CO, N2, C1, C2,OTHER HYDROCARBONS PERMEATE L ESS QUICKLY, AND SO ARE CALLED SLOW GASES.
MEMBRANE PERMEATION
MEMBRANE PERMEATION
ONE STAGE FLOW SCHEME RESIDUE (CO2 REDUCED)
FEED
MEMBRANE UNIT
PERMEATE (CO2 ENRICHED)
TWO STEP FLOW SCHEME RESIDUE (CO2 REDUCED
FEED
PERMEATE (CO2 ENRICHED)
TWO STAGE FLOW SCHEME RESIDUE (CO2 REDUCED)
FEED
PERMEATE (CO2 ENRICHED
MEMBRANE DESIGN CONSIDERATIONS
LOW COST
HIGH RELIABILITY
HIGH ON-STREAM TIME
EASY OPERATION
HIGH HYDROCARBON RECOVERY
LOW MAINTENANCE
LOW ENERGY CONSUMPTION
LOW WEIGHT AND SPACE REQUIREMENT
MEMBRANE PERFORMANCE THE MEMBRANE PERFORMANCE IS LOWERED DUE TO
LIQUIDS
HEAVY HYDROCARBONS(>C15)
CERTAIN CORROSION INHIBITOR
MEMBRANE SYSTEM PRETREATMENT
COALESCING FILTER FOR LIQUID AND MIST ELIMINATION
NON-REGENERABLE ADSORBENT GUARD BED FOR TRACE CONTAMINANT REMOVAL
PARTICLE FILTER FOR DUST REMOVAL AFTER THE ADSORBENT BED
HEATER FOR PROVIDING SUFFICIENT SUPERHEAT TO THE GAS
MEMBRANE SYSTEM PRETREATMENT
FEED
COALESCING FILTER
PARTICLE FILTER
ADSORBENT GUARD BED
HEATER
MEMBRANE
MEMBRANE SYSTEM PROJECTS
PAKISTAN
TAIWAN
MEXICO
SALAM & TAREK, EGYPT
WEST TEXAS, USA
NATURAL GAS DEHYDRATION
DEFINITION DEHYDRATION IS THE PROCESS USED TO REMOVE WATER FROM NATURAL GAS AND NATURAL GAS LIQUIDS.
IMPORTANCE
-
MEET A WATER CONTENT SPECIFICATION
-
PREVENT CORROSION
-
PREVENT DECREASE IN THE GAS HEATING VALUE
-
PREVENT HYDRATE FORMATION
-
REDUCE TRANSFER COST
MAIN FEATURES OF GAS DEHYDRATION THE SATURATED WATER CONTENT OF A GAS DEPENDS ON PRESSURE, TEMPERATURE AND COMPOSITION. SATURATED WATER CONTENT INCREASES AT HIGHER TEMPERATURE,LOWER PRESSURE AND LOW SPECIFIC GRAVITY. THE PRESENCE OF ACID GASES (i.e. CO2 & H2S) INCREASE THE WATER CONTENT IN THE NATURAL GAS
NATURAL GAS WATER CONTENT
SAT. WATER CONTENT = 1060 kg/106 SM3 @ 40ºC AND 7 MPa
Water Content of Natural Gas
SAT. WATER CONTENT = 61 Ib/M3 @ 100ºF AND 1000 PSIA
HYDRATES IN NATURAL GAS
DEFINITION A HYDRATE IS A PHYSICAL COMBINATION OF WATER AND OTHER SMALL HYDROCARBON MOLECULES TO FORM A SOLID CRYSTALLINE COMPOUND WHICH HAS AN “ ICE-LIKE ” APPERENCE, BUT WITH A DIFFERENT STUCTURE THAN ICE AND MUCH MORE DENSE THAN ICE.
HYDRATE PROBLEMS HYDRA HYDRATE TE FORMA FORMA TION IN GAS GA S A ND/OR ND/OR NGL SYSTEMS CAN PLUG PIPELINES, EQUIPMENT, AND INSTRUMENTS, RESTRICTING OR INTERRUPTING FLOW.
HYDRATE FORMATION NATURAL GAS GA S HYDR HYDRA A TES A RE FORM FORMED ED WHEN WHEN NATURAL NATURA L GAS COMPONENTS, NOTABLY METHANE, ETHANE, PROPANE, ISOBUTANE, HYDROGEN SULFIDE, CARBON DISUL DISUL FIDE AND NITROGEN NITROGEN ENTER ENTER THE WA WA TER LATTIC LA TTICE E POSITIONS AND OCCUPY THE VACANT LATTICE POSITIONS, POSITIONS, CA CA USING THE THE WATER WA TER TO SOLIDIFY AT AT TEMPERATURE CONSIDERABLY HIGHER THAN THE WATER FREEZING POINT. ENOUGH GASEOUS MOLECULES MUST ENTER ENTER THE LA L A TTICE AND OCCUPY THE THE VOIDS TO TO FORM A STABILIZED HYDRATE
HYDRATE TYPES
SMALL SMAL L ER MOL MOLECU ECUL L ES (CH4, (CH4, C2H6 C2H6,, CO2, CO2, H2S) H2S) STABIL STAB ILIZE IZE A BODY-CENTERED CUBIC CALLED STRUCTURE I.
L A RGER RGER MOL MOL ECUL ECUL ES (C3H (C3H8, 8, II- C4H10, C4H10, N-C4H1 N-C4H10) 0) FORM FORM A DIAMOND-LA DIAMOND-LATTI TTICE CE CAL CA L L ED STRUCT STRUCTURE URE II. II.
NORMAL PARAFFIN MOLECULES LARGER THAN N-C4H10 DO NOT FORM STRUCTURE I AND II HYDRATES AS THEY ARE A RE TOO LA L A RGE TO STAB ILIZE IL IZE THE LA L A TTICE. HOWEVER, SOME ISOPARAFFINS AND CYCLOALKANES LARGER THAN THA N PENTANE ARE A RE KNOWN K NOWN TO TO FORM FORM STRUCTURE STRUCTURE H HYDRATES.
HYDRATE TYPES
NITROGEN :
N 2 . 6 H 2 O
CARBON DIOXIDE:
CO 2 . 6 H 2 O
HYDROGEN SULFIDE :
H 2 S. 6 H 2 O
METHANE :
CH 4 .6 H 2 O
ETHANE :
C2 H 6 . 8 H 2 O
PROPANE :
C3 H 8 . 1 7 H 2 O
ISO-BUTANE :
I - C4 H 1 0 . 1 7 H 2 O
HYDRATES IN NATURAL GAS HYDRATE STRUCTURE TYPE
FROM A PRACTICAL VIEWPOINT, THE STRUCTURE TYPE DOES NOT AFFECT THE APPEARANCE, PROPERTIES, OR PROBLEMS CAUSED BY THE HYDRATE.
IT DOES, HOWEVER, HAVE A SIGNIFICANT EFFECT ON THE PRESSURE AND TEMPERATURE AT WHICH HYDRATES FORM. STRUCTURE II HYDRATES ARE MORE STABLE THAN STRUCTURE I. THIS IS WHY GASES CONTAINING C3H8 AND I-C4H10 WILL FORM HYDRATES AT HIGHER TEMPERATURES THAN SIMILAR GAS MIXTURES WHICH DO NOT CONTAIN THESE COMPONENTS.
HYDRATES IN NATURAL GAS FACTORS THAT AFFECT HYDRATE FORMATION THE CONDITIONS WHICH AFFECT HYDRATE FORMATION ARE:
TEMPERATURE PRESSURE COMPOSITION
IN GENERAL, HYDRATE FORMATION WILL OCCUR AS PRESSURE INCREASES AND/OR TEMPERATURE DECREASES TO THE FORMATION CONDITION. THE PRESENCE OF H2S IN NATURAL GAS MIXTURES RESULTS IN A SUBSTANTIALLY WARMER HYDRATE FORMATION TEMPERATURE AT A GIVEN PRESSURE. CO2, IN GENERAL, HAS A MUCH SMALLER IMPACT AND OFTEN REDUCES THE HYDRATE FORMATION TEMPERATURE AT FIXED PRESSURE FOR A HYDROCARBON GAS MIXTURE.
Simple Hydrate Prediction Correlation
What is th e hydrate temperature of a 0.7 specific g ravity natural gas at 7000 kPa?
Hydr ate temperature = 18º C
Ref. GPSA Data Book
Simple Hydrate Prediction Correlation What is th e hydrate temperature of a 0.7 specific g ravity natural gas at 1000 psia?
Hydr ate temperature = 65º F
Ref. GPSA Data Book
GAS DEHYDRATION TECHNIQUES
-
ABSORPTION USING LIQUID DESICANTS
-
ADSORPTION USING SOLID DESICANTS
-
DEHYDRATION USING CACL2
-
DEHYDRATION BY MEMBRANE PERMEATION TECHNOLOGY
HYDRATE INHIBITION
THE FORMATION OF HYDRATES CAN BE PREVENTED BY DEHYDRATING THE GAS OR LIQUID TO ELIMINATE THE FORMATION OF A CONDENSED WATER (LIQUID OR SOLID) PHASE.
IN SOME CASES, HOWEVER, DEHYDRATION MAY NOT BE PRACTICAL OR ECONOMICALLY FEASIBLE. IN THESE CASES, INHIBITION CAN BE AN EFFECTIVE METHOD OF PREVENTING HYDRATE FORMATION.
DEHYDRATION ADDITIVES THE FOLLOWING ADDITIVES ARE USED TO LOWER THE HYDRATE TEMPERATURE AT A CERTAIN PRESSURE -
METHANOL (CH3 OH ) ETHYLENE GLYCOL (C2H6O2) DIETHYLENE GLYCOL (C4H10O3) TRIETHYLENE GLYCOL (C6H14O4) TETRAETHYLENE GLYCOL (C8H18O5 )
DEHYDRATION ADDITIVES PROPERTIES -
HIGH ABSORPTION EFFICIENCY.
-
EASY AND ECONOMIC REGENERATION
-
NON CORROSIVE AND NON TOXIC
-
NO INTERACTION WITH THE HYDROCARBON PORTION OF THE GAS
-
NO OPERATIONAL PROBLEMS WHEN USED IN HIGH CONCENTRATIONS
DEHYDRATION FEATURES HYDRATE INHIBITION UTILIZES INJECTION OF ONE OF THE GLYCOLS OR METHANOL INTO A PROCESS STREAM FOR CONTINUOUS INJECTION IN SERVICES DOWN TO – 40°F, ONE OF THE GLYCOLS USUALLY OFFERS AN ECONOMIC ADVANTAGE VERSUS METHANOL RECOVERED BY DISTILLATION. ETHYLENE GLYCOL IS THE MOST POPULAR BECAUSE OF ITS LOWER COST, LOWER VISCOSITY AND SOLUBILITY IN LIQUID HYDROCARBONS. FOR LOW GAS VOLUMES , INFREQUENT OPERATION AND AT CRYOGENIC CONDITIONS (BELOW – 40°F) METHANOL USUALLY IS PREFERRED.
GLYCOL LOSSES -
FOAMING
-
HIGH GAS FLOW RATE IN THE CONTACTOR
-
RAPID CHANGES IN THE GAS FLOW RATES
-
PUMP LEAKAGE
-
GLYCOL CARRY OVER WITH THE GAS LEAVING THE CONTACTOR
-
LOW PH (< 3)
GLYCOL INJECTION PROCESS
GLYCOL INJECTION PROCESS
ABSORPTION USING LIQUID DESICANTS
ADSORPTION USING SOLID DESICANTS
DEHYDRATION USING SOLID DESICANTS
DEHYDRATION USING SOLID DESICANTS
SOLID DESICANT PROPERTIES
CALCIUM DI CLORIDE -Calcium chloride (CaCl2) can be used as a consumable desiccant to dehydrate natural gas. - 3/8” to 3/4 “ CaCl2 pellets are installed in a fixed bed much like a dry desiccant tower. - Outlet water contents of 1 lb/MMscf have been achieved with CaCl2 dehydrators. Typical CaCl2 capacity is 0.3 lb CaCl2 per lb H20. - CaCl2 dehydrators may offer a viable alternative to glycol units on low rate, remote dry gas wells. - The CaCl2 must be changed out periodically. In low capacity – high rate units this may be as often as every 2-3 weeks. - Brine disposal raises environmental issues.
MERCURY REMOVAL
VARIOUS FORMS OF MERCURY
-
. ELEMENTAL MERCURY (HG )
-
ORGANIC FORM (HG (CH3)2 ,HG (C2H5)2 )
-
INORGANIC FORM (HG CL2)
-
SUSPENDED MERCURY COMPOUNDS (MERCURIC SULFIDE)
DIFFERENCE BETWEEN VARIOUS FORMS OF MERCURY
-
VAPOR PRESSURE
-
SOLUBILITY
-
PHASE
-
ADSORPTION PROPERTIES
REASONS FOR MERCURY REMOVAL -
DEPOSITS IN CRYOGENIC EQUIPMENT
-
CAUSE CRACKING OF WELDED ALUMINUM HEAT EXCHANGER
-
REDUCE PRODUCTS (C1, C2, C3, C4, C5+) QUALITY
-
CORROSION
-
DEPOSITS IN THE MOLECULAR SIEVE, GLYCOL UNITS AND ACID GAS REMOVAL UNITS. (DIFFICULT DISPOSAL AND REGENERATION)
-
POISON THE DOWN STREAM CATALYST IN ETHYLENE, MTBE, AROMATICS AND OLEFINE PLANTS.
-
SAFETY AND HEALTH PROBLEMS DURING EQUIPMENT MAINTENANCE AND INSPECTION
MERCURY CONTENT
MERCURY CONTENT IN N.G SHOULD BE NIL OR LESS THAN 0.01 MICROGRAM PER NORMAL CUBIC METER
Mercury Removal and Recovery System
Hg Removal Without Treatment Of The Spent Regeneration Gas
NATURAL GAS REFRIGERATION
REFRIGERATION CYCLE
-
EXPANSION
-
EVAPORATION
-
COMPRESSION
-
CONDENSATION
PURE COMPONENT PHASE BEHAVIOR
PHASE BEHAVIOR OF C2-NC7 SYSTEM
REFRIGERATION CYCLE PROCESS FLOW DIAGRAM
COMPRESSOR
C
EVAPORATOR
D
CONDENSER B EXPANSION VALVE
A
REFRIGERATION CYCLE PRESSURE-ENTHALPY DIAGRAM
) I S P ( E R U S S E R P
CRITICAL POINT
A D
B
C
ENTHALPY (Btu / Ib)
REFRIGERATION SYSTEM PRESSURE DROP
-
CONDENSER PRESSURE DROP :
-
LINE HYDRAULIC LOSSES
3.0 TO 7.0 PSI
EVAPORATOR TO COMPRESSOR : 0.1 TO 1.5 PSI COMPRESSOR TO CONDENSER : 1.0 TO 2.0 PSI CONDENSER TO RECEIVER : 0.5 TO 1 PSI
Refrigeration Mechanical
ONE STAGE REFRIGERATION SYSTEM
COMPRESSOR 250 psia
Air Cooler
P1 = 10 psi
14.5 psia
P1 = 1.5 psi Q= 35 MMBTU/HR SUCTION DRUM
-40 oF 16 psia
EVAPORATOR OR CHILLAR
120 oF 240 psia
RECEIVER
TWO STAGES REFRIGERATION SYSTEM
250 psia
P1 = 10 psi
P = 60 psi P1 = 1.5 psi
P1 = 2 psi
14.5 psia -40 oF 16 psia
SUCTION DRUM
Q= 25 MMBTU/HR
120 120ooFF 240 240psia psia 25 oF 62 psia
Q= 10 MMBTU/HR
THREE STAGES REFRIGERATION SYSTEM
P = 34 psi
82 psia
200 psia
P1 = 10 psi
P1 = 1.5 psi 14.5 psia
-40 oF 16 psia
Q= 23 MMBTU/HR
-4 oF 36 psia
Q= 10 MMBTU/HR
44 oF 84 psia
120 120ooFF 190 240psia psia
Q= 7 MMBTU/HR
Q= 3 MMBTU/HR
CASCADE REFRIGERATION SYSTEM 1
2
P = 51 psi
17 psia
153 psia
-40 oF 16 psia
-120 oF 18.5 psia Q= 15 MMBTU/HR
Q= 30.71 MMBTU/HR
oF -25 120oF 148 240psia psia
-78.5 oF 52.5 psia Q= 10 MMBTU/HR Q= 3 MMBTU/HR
ETHANE SYSTEM
PROPANESYSTEM 1 14.5 psia
2
P = 34 psi
-40 oF 16 psia
3 82 psia
-4 oF 36 psia
200 psia
44 oF 84 psia
100 120ooFF 190 240psia psia
Q= 7 MMBTU/HR Q= 23 MMBTU/HR
Q= 10 MMBTU/HR Q= 3 MMBTU/HR 141
REFRIGERANTS PHYSICAL PROPERTIES
TURBO EXPANDERS
USE OF TURBOEXPANDERS - FREE PRESSURE DROP IN THE GAS STREAM - LEAN GAS -
HIGH ETHANE RECOVERY REQUIREMENTS(OVER 30% ETHANE RECOVERY)
- COMPACT PLANT LAY OUT -
HIGH UTILITY COST
-
FLEXIBILITY OF OPERATION
TERBO EXPANDERS
TERBO EXPANDERS
FRACTIONATION
FRACTIONATOR SECTIONS
FRACTIONATORS PRODUCTS
-
DEMETHANIZED PRODUCT (C2+) DEETHANIZED PRODUCT (C3+) ETHANE/PROPANE MIXTURES (EP ) COMMERCIAL PROPANE PROPANE/BUTANE MIXTURE (LPG) BUTANE(S) BUTANE/GASOLINE MIXTURES NATURAL GASOLINE MIXTURES WITH A VAPOR PRESSURE SPECIFICATION
FRACTIONATOR TRAIN
What are those? -
NGL ?
-
LPG ?
-
LNG ?
NGL NATURAL GAS LIQUIDS ITS COMPOSITION IS MAINLY
ETHANE+
LPG LIQUIFIED PETROLEUM GAS ITS COMPOSITION IS MAINLY
PROPANE & BUTANES
LNG LIQUIFIED NATURAL GAS ITS COMPOSITION IS MAINLY
METHANE & ETHANE
Gas Pr P r o c es s i n g
Gas conditioning
LPG plant
NGL plant
LNG plant
Gas Con Condi diti tion onin ing g To meet sales gas specifications only – No further processing
– Water removal – CO2 /H2S removal – Hydrocarbon dew point control
NGL Ex E x t r ac t i o n
In addition to meeting sales gas specifications – further processing is undertaken to increase NGL recovery. – NGL is more more valuable valuable as a saleab saleable le product product than than as a natural gas constituent Ethane Propane Butanes Natural Gasoline (iC5+) Extraction levels limited by gas sales specifications (heating value) and economics
NGL Ex E x t r ac t i o n Pr o c e s s Ty p e s
Adsorption:
Hydrocarbon Recovery Units
Absorption:
Lean Oil
Condensation: Mechanical Refrigeration Expander Valve (LTS, LTX, JT)
Ad A d s o r p t i o n
Ab A b s o r p t i o n Pro Pr o c ess es s (Ref r i g er at ed Le L ean Oil Pl an t )
Refrigeration Mechanical
Expander Process
Valve Expansion Process
LNG
LNG LIQUIFIED NATURAL GAS
Why LNG ??? Pipelines can not be used for gas export because of: – Geography • Distance – no local gas market • Physical terrain – mountain ranges • Water depth – Politics • International agreements required • Political risk – Economics • Size • distance
Why LNG? • 600:1 volume reduction
Typical LNG Properties • • • • • • • • •
Boiling point -160 to -162 °C Molecular weight 16 to 19 Odor none Color none Density 425 – 485 kg/m3 Calorific value 1030 – 1180 Btu/scf Specific heat capacity 2.2 – 3.7 kJ/kg/°C Viscosity 0.11 – 0.18 cP Thermal conductivity 0.19 – 0.22 W/m/°C
Typical LNG Product Specification
LNG PROCESS FACILTIES
FEED PREPARATION FACILITIES
NGL RECOVERY FACILITIES
STORAGE AND SHIPPING FACILITIES
LIQUIFICTION FACILITIES
LNG Process Facilities
Typical Gas Processing Stages • Gas Compression • Phase Separation • Acid Gas Removal • Sulphur Recovery • Dehydration • Mercury Removal • NGL recovery
Acid Gas Removal • CO Removal – Solidification in liquefaction plant – Reduce corrosion issues • H2S Removal – Hazardous compound – To meet LNG specification – Reduce corrosion issues • Organic Sulphur Removal – To meet LNG specification • Amine processes are the industry standard – Hybrid solvents gaining in popularity
Typical Amine Plant Layout
Dehydration • Water removal to prevent solidification in the liquefaction plant • Minimizes corrosion issues • Specification < 1 ppmv • Adsorption on Molecular Sieve is the industry standard
Dehydration
Mercury Removal • Trace contaminant but accumulates in plant • Mercury will cause failure of aluminum equipment – Must be removed prior to liquefaction plant • Contamination of liquid streams – Beneficial to remove upstream of processing units • Removal by Sacrificial Beds – Sulphided activated carbon – Metal sulphide
NGL Recovery system Demethanizer •Separates CH4 from heavier components •Cryogenic cooling followed by fractionation •Methane to sales or LNG plant •Residue to de-ethanizer
De-ethanizer •Separates Ethane from heavier hydrocarbons •Fractionation column •Ethane to sales or mixed with methane
NGL Recovery System •Depropanizer • Separates Propane from heavier
hydrocarbons • Fractionation column Debutanizer • LPG for sale • Residual condensate to oil
NGL Recovery System
LNG LIQUIFICATION TECHNOLOGY COMPARISON
LIQUIFICATION PROCESSES
CASCADE CYCLE
(PHILLIPS,AIR PRODUCT)
C3/MR CYCLE
MRCYCLE
(APCI , PRICHARD)
MR/MR CYCLE
(APCI, TECHNIP/SNAM)
(APCI)
LNG PRODUCTION WITH DIFFERENT REFRIGERATION CYCLES TYPE
CASCADE
LICENSOR
PLANTS
PHILLIPS PET. Co. & APCI
4
APCI & PRITCHARD
1
TOTAL MMTA
11.5
%
9
SINGLE PRESSURE MIXED REFRIGERANT(MR)
PROPANE PRECOOLED/MIXED REFRIGERANT(C3/MR)
APCI
MIXED REFRIGERANT PRECOOLED/MIXED REFRIGERANT
APCI &(TEARLAC) by TECHNIP / SNAMPROJETTI
2.4
2
25
109.3
84
3
6.6
5
COMPARISION BETWEEN THE TWO MAIN TECHNOLOGIES FOR LNG LIQUEFACTION PROCESS
AIR PRODUCTS AND CHEMICALS INC (APCI)
THE PHILLIPS OPTIMIZEED CASCADE PROCESS
LIQUEFACTION PROCESS APCI PROCESS The APCI process utilizes a propane pre-cooled / mixed component refrigerant (MCR) system . PHILLIPS PROCESS The Phillips optimized cascade process utilizes three cascade pure component refrigeration system . (Propane - Ethylene Methane)
FLEXIBILITY FOR FEED STOCK CHANGES
APCI process can accommodate varying feed stock better by allowing for adjustment of MR composition
INLET COMPOSITION:HIGH NITROGEN
Both processes can be designed to handle relatively high nitrogen feeds .
NGL RECOVERY CAPABILITY
There is no difference between the two technologies for the NGL Fractionation Section.
PROCESS DESIGN COMPLEXITY APCI PROCESS
The key to optimizing the design ,is optimization of the MCR blend and selection of pressure levels for the chillers. PHILLIPS PROCESS
Optimization of chiller pressures is the main factor for process design Both technologies are similar in complexity level .
THERMODYNAMIC CYCLE EFFICIENCY APCI PROCESS 42-45% PHILLIPS PROCESS 39-42% Theoretical minimum work EFFICIENCY = Total work
COMPRESSOR DRIVERS APCI PROCESS Utilize larger sized refrigeration compressor drivers.(Frame 6&7)
PHILLIPS PROCESS Utilize six frame 5C for 3.6 MTPA plant.
RELIABILITY / AVAILABILITY OF THE CRYOGENIC HEAT EXCHANGER APCI PROCESS The main heat exchanger used in the APCI process has been utilized in numerous LNG applications. PHILLIPS PROCESS The brazed aluminum heat exchangers and equipment used in PHILLIPS process are utilized in several LNG plants as well as numerous gas processing facilities worldwide.
PLANT INFRASTRUCTURE
The remainder of the plant and marine facilities will be similar for both process technologies .i.e. LNG storage tanks, loading system, jetty and marine facilities, fire protection equipment, utility systems, etc.
APCI Propane Pre-Cooled Mixed Refrigerant
Cascade Refrigeration
Phillips Optimized Cascade
Common Features • Cryogenic columns • Refrigerant Make-up • Compressor & Driver Selection • Cooling media
Egyptian LNG Plants • Egypt LNG (SE-GAS)
-
Located at Damietta Union Fenosa APCI Propane Pre-cooled Mixed Refrigerant process 1 x 4.5 mtpa train
Egyptian LNG Plants • Egyptian LNG – Located at Idku – BG Group, Edison, Gaz de France, EGPC, Egas – Phillips Optimized Cascade – Under construction by Bechtel
- 1 x 3.6 mtpa train
LNG storage LNG Storage Tanks realizes on average 45% to 65% of total Import terminal costs(£10s millions). – Metallurgy – Cryogenic – Insulation – Cold seals – Limited vendors – Seismic considerations • Construction of the order 2 to 4 years for tanks. •
GTL TECHNOLOLOGY
LIQUIFIED NATURAL GAS (LNG)
NATURAL GAS LIQUID RECOVERY (NGL)
NATURAL GAS APPLICATION
PETROCHEMICAL INDUSTRIES
GAS TO LIQUID FUEL (GTL)
WHAT IS GTL??
• “ GTL” IS LOOSELY DEFINED TERM THAT IS GENERALLY USED TO DESCRIBE CHEMICAL CONVERSION OF NATURAL GAS TO SOME OF LIQUID PRODUCTS USING FISCHER TROPSCH TECHNOLOGY.
CONVERSION OF NATURAL GAS TO LIQUID FUEL
DIRECT APPROACH (UNDER RESEARCH)
INDIRECT APPROACH
CONVERSION OF N.G TO SYNTHESIS
CONVERSION OF SYNTHESIS TO LIQUID FUEL
100 MMSCFD N.G
GTL UNIT
10,000 BPSD LIQUID FUEL
50 MWH ELECTRICITY
15,000BBL/DAY WATER
GTL UNIT • THE LIQUID FUEL PRODUCED FROM GTL UNITS CAN BE DISTILLATED TO NAPHTHA, KEROSENE, GAS OIL ,DIESEL OIL.
• WAXES AND LUBE OIL FEED STOCKS AND DETERGENT CAN ALSO BE PRODUCED FROM GTL UNITS. • THE PRODUCED WATER CAN BE USED AS BOILER FEED WATER, POTABLE WATER (AFTER TREATMENT),IRRIGATION • THE GENERATED EXOTHEMIC HEAT ARE USED TO GENERATE ELECTRICAL HEAT WHICH IS ENOUGH TO OPERATE THE UNIT AND CAN EXPORT THE SURPLUS .
GTL TECHNOLOGY
WAXY SYNCRUDE NATURAL
GAS
NATURAL GAS REFORMING
SYNTHESIS GAS
FISHER-TROPSCH CONVERSION
PRODUCT WORK UP
(HYDROCARBON)
• MIDDLE DISTILLATE FUEL • NAPHTHA • GASOLINE
GTL TECHNOLOGY HAS THREE MAJOR PROCESS STEPS • STEP-1 NATURAL GAS REFORMING , CONVERTS NATURAL GAS INTO SYNTHESIS GAS, (A MIXTURE OF CARBON MONO OXIDE (CO), AND HYDROGEN (H2)). CH4 + H2O
CO + 3H2
THIS PROCESS TECHNOLOGY IS A CONVENTIONAL PROCESS TECHNOLOGY HAS BEEN USED IN MANY COMMERCIAL FACILITIES IN PETROLEUM REFINERIES ,METHANOL, AMMONIA AND UREA PLANTS AND OTHER RELATED INDUSTRIES FOR EXAMPLE H2 PLANT.
•
STEP-2
UPGRADE THE SYNTHESIS GASES INTO WAXY HYDOCARBON BY USING FISHER - TROPSCH TECHNOLOGY USING CATALYST IN A FISHER - TROPSCH REACTOR. CO +2H2
CH2 +H2O (FISHER- TROPSCH REACTION)
THIS CONVERSION STEP (POLYMERIZATION) IS THE HEART OF THE PROCESS WHICH IS CONVENTIAL PROVEN PROCESS TECHNOLOGY IN THE PETROLEUM REFINING INDUSTRY APPLIED WORLD WIDE SINCE MORE THAN 25 YEARS
•
STEP-3
THE HYDRACARBON ARE UPGRADED TO HIGH QUALITY MIDDLE DISTILLATE FUEL (KEROSENE,DIESEL OIL AND SOME NAPHTHA) BY USING STANDARD MILD HYDROCRACKING OR THERMAL CRACKING , HYDROISOMERIZATION PROCESS FOR THE PRODUCED WAX AND DISTILLATION FOR PRODUCT SEPARATION .
PRODUCTION OF SYNTHESIS GAS
STEAM REFORMING
PARTIAL OXIDATION
AUTOTHERMAL REFORMING
STEAM REFORMING PROCESS CAN PRODUCE SYNTHESIS GAS FROM NATURAL GAS USING STEAM REFORMER OVER A NICKLE CATALYST LOADED IN THE REFORMER TUBES . THE H2 / CO PRODUCT RATIO IS 1 : 3 .
•
20 BAR
CH4 + H2O •
CO +3H2
STEAM REFORMING PROCESS IS OFFERED BY : -
•
800-900 ° C
HALDOR TOPSOE. FOSTER WHEELER COPORATION . KTI B.V. LURGI AG . UHDE GMBH .
ADVANCED STEAM REFORMING CAN PRODUCE A SYNTHESIS WITH H2 / CO PRODUCT RATIO < 1 .
•
PARTIAL OXIDATION PROCESS
CAN PRODUCE SYNTHESIS GAS FROM ENTIRE RANGE OF GASEOUS AND LIQUID HYDROCARBON AS WELL AS SOLIDS (COAL , COKE ) .THE PROCESS IS CONTINOUS NON CATALYTIC PARTIAL OXIDATION USING OXYGEN OR AIR AS AN OXIDANT AND WAS DONE IN A REFRACTORY -LINED PRESSURE VESSEL . THE H2 / CO PRODUCT RATIO IS 1.7 :1 . 2CH4 + O2
140+ BAR 1200-1500 °C
2CO + 4H2 .
• PARTIAL OXIDATION PROCESSIS IS OFFERED BY
- TEXACO INC . - ROYAL DUTCH .
•
AUTOTHERMAL REFORMING PROCESS CAN PRODUCE SYNTHESIS GAS FROM NATURAL GAS , LPG OR NAPHTHA .THE PROCESS COMBINES THE PARTIAL OXIDATION AND THE ADIABATIC STEAM REFORMING USING AUTOTHERMAL REFORMER REACTOR WHICH IS A REFRACTORY -LINED VESSEL CONTAINING BURNER LOCATED AT THE TOP OF THE VESSEL , COMBUSTION CHAMBER BELOW THE BURNER AND CATALYST BED INCLUDING NICKLE CATALYST. THE H2 / CO PRODUCT RATIO IS 2 :1 .
• AUTOTHERMAL REFORMING PROCESS IS OFFERED BY
- HALDOR TOPSOE . - LURGI AG .
THE FISCHER - TROPSCH TECHNOLOGY HAS BEEN DEVELOPED BY NUMBER OF OIL MAJOR COMPANIES (MOBIL ,EXXON CORPORATION ,ROYAL DUTCH/SHELL AND BP AMOCO BY SMALL GTL COMPANIES ,SUCH AS SYNTROLEUM CORPORATION,RENTECH INC.AND BY SASOL) .
THE DIFFERERNCE BETWEEN EACH TECHNOLOGY IS DEPENDING ON THE FOLLOWING: -
TYPE OF REACTOR TYPE OF CATALYST OPERATING CONDITIONS UNIT CAPACITY AND OTHERS DETAILED DESIGN
MOBIL GTL PROCESS TECHNOLOGY
N.G
S.G SYNTHESIS GAS
METHANOL
MTG PROCESS
GASOLINE
SYNTROLEUM GTL PROCESS TECHNOLOGY
N.G
AUTOTHERMAL REFORMING
SYNTHESIS GAS
SYNTROLEUM REACTOR
SYNTHESIS CRUDE OIL
SYNTROLEUM MAIN FEATURES •
SYNTROLEUM PROCESS USED THE AUTO THERMAL REFORMER REACTOR TO PRODUCE A NITROGEN DILUTED SYNTHESIS GAS CONSISTING PRIMARILY OF CARBON MONO OXIDE AND HYDROGEN .
•
SYNTROLEUM GAS IS CONVERTED INTO SYNTHESIS CRUDE IN A REACTOR CONTAINING CATALYST DEVELOPED BY SYNTROLEUM .
• SYNTROLEUM PROCESS ALSO PLANS TO BUILD GTL PLANTS THAT CONVERTS N.G INTO A MARGIN OF PRODUCTS SUCH AS SYNTHETIC LUBRICANTS , SOLVENTS AND CHEMICAL FEED STOCKS . •
GAS TURBINES OR HEATERS MIGHT BE USED IN THE PROCESS TO BURN THE LOW HEATING VALUE OF TAIL GAS THAT IS PRODUCED BY THE PROCESS WHICH WOULD RESULT IN THE NEED TO INCORPORATE OTHER METHOD TO GENERATE HORSEPOWER FOR 23 THE COMPRESSION PROCESS .
SHELL MIDDLE DISTILLATE SYNTHESIS (SMDS) GTL PROCESS TECHNOLOGY
N.G
SHELL GASIFICATION PROCESS (SGP)
SYNTHESIS GAS
HEAVY PARAFFINS SYNTHESIS (HPS) REACTOR
WAXY SYNCRUDE
PRODUCT WORK UP
• PARAFFINIC SOLVENT • MIDDLE DISTILLATES • WAXY RAFINATE • PARAFFINS • WAX
SHELL MIDDLE DISTILLATE SYNTHESIS (SMDS) MAIN FEATURES • SMDS USES PARTIAL OXIDATION PROCESS TECHNOLOGY FOR THE SHELL GASIFICATION PROCESS (SGP)TO PRODUCE SYNTHESIS GAS FROM NATURAL GAS . • SHELL MDS UTILIZES THE HEAVY PARAFFINS SYNTHESIS REACTOR (HPSR) IN WHICH SYNTHESIS GAS IS CONVERTED TO PARRAFINS .
SASOL GTL PROCESS TECHNOLOGY
N.G
AUTOTHERMAL REFORMING
SYNTHESIS SASOL SLURRY WAXY PHASE REACTOR GAS HYDROCARBON
PRODUCT UPGRADING UNITS LIQUID FUEL (80 % DIESEL & 20 % NAPHTHA)
SASOL MAIN FEATURES •
SASOL USED AUTO THERMAL REACTOR (ATR ) TO PRODUCE SYNTHESIS GAS FROM NATURAL GAS .
•
BY SASOL PROCESS THE HYDROCARBONS ARE SYNTHESIS BY A CHAIN GROWTH PROCESS. THE LENGTH OF THE CHAIN BEING DETERMINED BY THE CATALYST SELECTIVITY.
•
SASOL HAS DEVELOPED HIGH PERFORMANCE COBALT - BASED AND IRON - BASED CATALYST .
•
SASOL HAS DEVELOPED THE TWO TYPES OF FISCHER - TROPSCH CONVERSION TECHNOLOGY BY USING TWO TYPES OF REACTORS; SLURRY PHASE REACTOR & SASOL ADVANCED SYNTHOL REACTOR.
SASOL MAIN FEATURES CONTINUED •
SASOL UTILIZES THE SLURRY PHASE REACTOR TO PRODUCE WAXES AND MIDDLE DISTILLATE FUELS . THIS TECHNOLOGY WAS DEVELOPED FROM THE CONVENTIONAL TUBULAR FIXED REACTOR
•
SASOL UTILIZES THE ADVANCED SYNTHOL REACTOR TO PRODUCE MAINLY LIGHT OLEFIN AND GASOLINE FRACTION.
•
PRODUCT UPGRADED MAKE USE OF A STANDARD HYDROCRACKING AND HYDROISOMERIZATION PROCESS AND DISTILLATION PROCESS.
•
SASOL’S SLURRY PHASE DISTILLATE PROCESS (SSPD) CAN PRODUCE THE DIESEL OIL WITH CETANE NUMBER >70, AROMATIC CONTENT < 3 %VOL.AND WITH NO SULFUR .
SASOL SLURRY PHASE REACTOR (SSPR) 1- PREHEATED SYNTHESIS GAS IS FED TO THE BOTTOM OF THE REACTOR WHERE IT IS DISTRIBUTED INTO THE SLURRY CONSISTING OF LIQUID WAX AND CATALYST PARTICLES. 2- THE GAS BUBBLES UPWARD THROUGH THE SLURRY AND IT DIFFUSES INTO THE SLURRY AND CONVERTS INTO MORE WAX BY THE FISHER - TROPSCH REACTION . 3- THE HEAT GENERATED FROM THIS REACTION IS REMOVED THROUGH THE REACTOR’S COOLING COILS,WHICH GENERATE STEAM . 4- THE WAX PRODUCT IS SEPARATED FROM THE SLURRY CONTAINING THE CATALYST PARTICLES IN A PROPRIETARY PROCESS DEVELOPED BY SASOL . 5-
THE LIGHTER, MORE VOLATILE FRACTIONS LEAVE IN GAS STREAM FROM THE TOP OF THE REACTOR.THE GAS STREAM IS COOLED TO RECOVER THE LIGHTER CUTS AND WATER .THE HYDROCARBON STREAMS ARE SENT TO THE PRODUCT UPGRADING UNIT , WHILE THE WATER STREAM IS TREATED IN THE WATER RECOVERY UNIT.
RENTECH INC. GTL PROCESS TECHNOLOGY
N.G
PARTIAL OXIDATION
SYNTHESIS GAS
SLURRY SYNTHESIS REACTOR
WAXY HYDROCARBON
PRODUCT UPGRADING UNITS
LIQUID FUEL ( NAPHTHA, KEROSENE & DIESEL )
RENTECH MAIN FEATURES •
RENTECH USED PARTIAL OXIDATION REACTOR (POX) TO PRODUCE SYNTHESIS GAS FROM NATURAL GAS .
•
BY RENTECH PROCESS, THE HYDROCARBON ARE SYNTHESIS BY FORMING LONG AND SHORT STRAIGHT CHAIN HYDROCARBONS .
•
RENTECH HAS DEVELOPED HIGH PERFORMANCE IRON BASED CATALYST POWDER .
•
RENTECH HAS DEVELOPED THE FISCHER - TROPSCH CONVERSION TECHNOLOGY BY USING VERTICAL SYNTHESIS REACTOR.
•
PRODUCT UPGRADED MAKE USE OF A STANDARD HYDROCRACKING OR THERMAL CRACKING, HYDROISOMERIZATION PROCESS ,VACUUM SEPARATION AND DISTILLATION PROCESS .
RENTECH VERTICAL SYNTHESIS REACTOR 1- PREHEATED SYNTHESIS GAS IS FED TO THE BOTTOM OF THE REACTOR WHERE THE IRON BASED CATALYST POWDER IS SUSPENDED IN A MOLTEN WAX SLURRY . 2- THE SYNTHESIS GAS BUBBLES UPWARD THROUGH THE SLURRY , CONTACTS THE CATALYST PARTICALS AND FORMS THE STRAIGHT CHAIN HYDROCARBONS . 3- THE LONG STRAIGHT CHAIN HYDROCARBONS ARE DRAWN OFF AS A LIQUID HEAVY WAX . THE SHORT CHAIN HYDROCARBONS ARE WITHDRAWN AS OVERHEAD VAPORS AND CONDENSED TO SOFT WAX , DIESEL AND NAPHTHA. ANY HYDROCARBONS NOT CONDENSED ARE RECYCLED TO THE PLANT INLET OR ARE USED AS FUEL GAS FOR NECESSARY POWER GENERATION.
COMMERCIAL APPLICATIONS OF “ GTL” TECHNOLOGY •
IN GERMANY :
THIS TECHNOLOGY WAS ORIGANILLY DEVELOPED DURING WORLD WAR II WHEN IT WAS USED TO PRODUCE LIQUID FUELS FROM COALS . SOME FACTORIES ARE STILL USING IT. •
IN NEW ZELAND :
MOBIL COMPANY USED THIS TECHNOLOGY IN 1986 TO PRODUCE 14,500 BARREL / DAY GASOLINE FROM NATURAL GAS.
COMMERCIAL APPLICATIONS OF “ GTL” TECHNOLOGY CONTINUED •
IN SOUTH AFRICA : SINCE 1955,SOSAL TECHNOLOGY IS USED TO CONVERT COAL INTO SUPER CLEAN LIQUID FUELS WITH CAPACITY OF 195,000 BPSD WHICH REPRESENTS 43 % OF LIQUID FUELS CONSUMPTION IN SOUTH AFRICA . SINCE 1993 ,ANOTHER PLANT USING SASOL TECHNOLOGY PRODUCING LIQUID FUEL FROM NATURAL GAS WITH CAPACITY OF 2500 BARREL / DAY. THIS TECHNOLOGY IS SUPPORTED BY SASOL COMPANY MORE THAN 40 YEARS OF COMMERCIAL PRODUCTION BASED ON FISHER - TROPSCH KNOW-HOW . SASOL COMPANY CONTINUES DEVELOPING THE PROCESS TECHNOLOGIES TO ENSURE CONTINUOUS PROCESS REFINEMENT AND COST REDUCTION .
COMMERCIAL APPLICATIONS OF “GTL” TECHNOLOGY CONTINUED •
IN MALAYSIA :
SHELL MIDDLE DISTILLATE SYNTHESIS (SMDS) PROCESS WAS APPLIED AT PLANT IN MALAYSIA “BINTULU PLANT “ ,WHICH WENT ON STREAM IN 1993 . THE PLANT CONVERTS 10MMSCFD OF NATURAL GAS TO 12,000 BPSD OF LIQUID PRODUCTS.
COMMERCIAL APPLICATIONS OF “GTL” TECHNOLOGY CONTINUED •
IN QATAR :
SASOL ,PHILIPS AND QATAR GENERAL PETROLEUM COMPANY “QGPC ”HAVE SIGNED A JOIN VENTURE FOR GTL PROJECTS USING N.G TO PRODUCE 20,000 BPSD OF MIDDLE DISTILLASTE AT RASLAFFAN. THIS PROJECT IS SCHEDULED TO START YEAR 2002. EXXON NEGOTIATES WITH QGPC TO BUILD GTL PLANT TO CONVERT 500 - 1000 MMSCFD NATURAL GAS TO 50,000 - 100,000 BPSD MIDDLE DISTILLATE AND OTHER LIQUID PRODUCT .
PRODUCTS QUALITY
•
GASOLINE
-
OCTANE NO. : 93 % AROMATICS : 32 % SATURATED COMPOUNDS : 60% OLEFINS : 8%
DIESEL OIL PROPERTIES FLASH POINT SPECIFIC GRAVITY SULPHUR CETANE NUMBER CLOUD POINT AROMATICS
CONVENTIONAL
GTL
71
81
0.84
0.78
350 PPM
< 5 PPM *
45
74
- 17
- 12 <1
* SASOL TECHNOLOGY CAN PRODUCE DIESEL WITH SULPHUR CONTENT < 1 PPM
ENVIROMENTAL CONSIDERATIONS PROPERTIES
GTL PRODUCTS
PARAFINS
-
-
98 %
AROMATICS
20-28 %
6 % MAX.
1 %.
NAPHTHENES
-
SULPHUR NITROGEN CETANE NUMBER •
LOCAL GAS EUROPE GAS OIL ON 1997 OIL ON 2000
0.7 - 1.1 % 48-51
0.02 % MAX.
1% NIL
NA
NIL
58 (MIN)
70
THE ABOVE TABLES SHOW THAT GTL SUPER CLEAN PRODUCTS COULD BE BLENDED WITH CONVENTIONAL PETROLEUM REFINING PRODUCTS FOR BOTH LOCAL ENVIRONMENTAL IMPROVEMENT AND EXPORT .
