GSU AND GDU
- 1. Gas Sweetening & Dehydration Process Presented by: Aniruddh Singh Shekhawat
- 2. •Introduction •H2S & it’s need of processing •Gas Sweetening Process •Gas dehydration Process •Recap
- 3. What is Sour Gas? Sour Gas is a Natural Hydrocarbon gas with acid gases; most commonly Carbon dioxide, hydrogen sulphide & to some extent mercaptans. Natural Gas Non-Hydrocarbon (Acid Gas) Hydrocarbon
- 5. Gas Terminal GSU DPDU CFU GDU LPGU KRU CWU SRU 36” 42” Sulfur Sweet gas to HBJ PL Sweet gas to Local consumers LPG ARN HC SKO ACID GAS SOUR GAS SOUR COND From Offshore HSD ATF
- 6. • H2S is a highly toxic & Colourless flammable gas • Corrosive to all metals (less corrosive to SS) • Can cause catalyst poisoning in refinery processes • On combustion forms toxic gas SO2. • 4.3% LEL and 45% HEL by volume with an auto- ignition temperature of 500oF (292oC) • Heavier than air (1.18 times heavier) • It may accumulate in dangerous concentrations in drains, valve pits, vessels and tanks.
- 7. • Has no heating value. •Yet constitutes a volume-filler • Corrosive in presence of water. • Promotes hydrate formation. CO2
- 8. Note: The composition of components is from ADMA Company Components Mole Fraction at I/L Mole Fraction at O/L Hydrogen Sulphide Methane Ethane Propane Isobutane nbutane IsoPentane nPentane Hexane Carbon Dioxide 0.013% 81.7% 6.34% 3.72% 0.70 % 0.86% 0.15% 0.13% 0.05% 6.30% 0.0004% 82.8% 6.39% 3.77% 0.74% 0.84% 0.16% 0.15% 0.07% 4.9%
- 9. Significant factors are; 1. Type & conc. of impurities. 2. Degree of removal of impurities or selectivity of acid component removal. 3. Volume of the Gas stream. 4. Temp. & Pr. Conditions 5. HC Composition. 6. Economics
- 10. 1. Non-regenerative 2. Regenerative process • Physical absorption-water wash, selexol, fluor solvent etc. • Chemical absorption- The alkonol- amine processes 3. Regenerative process with elemental sulphur recovery
- 12. PHASE I TRAIN # PHASE II PHASE III PHASE III A CAPACITY 31 32 33 34 35 36 37 38 5.6 MMSCMD each 5.6 MMSCMD each 5.6 MMSCMD each 6.3 MMSCMD each
- 14. Amine type Chemical formula Mol. Wt. Vapour pressure at 370C Removal capacity % MEA (Mono ethanol amine) HO C2H4NH2 61.08 1.05 100 DEA (Diethanol amine) (HOC2H4)2NH 105.14 0.058 58 TEA (Triethanol amine) (HOC2H4)3N 148.19 0.0063 41 DGA (Di glycolamine) H(OC2H4)2NH2 105.14 0.160 58 DIPA (Di-isopropanol amine) (HOC3H6)2NH 133.19 0.010 46 MDEA (Methyl diethanol amine) (HOC2H4)2NH3 119.17 0.0061 51
- 15. P301A/B, MULTISTAGE CENTRIFUGAL PUMP E305 PREHEATER V301 INLET KOD SWEET GAS OUT V302 OUTLET KOD SWEET GAS TO GDU SOUR GAS FROM SLUG CATCHER ABSORBER COLUMN C301 TRAY 9 TRAY 7 TRAY 5 TRAY 3 TRAY 1 SOUR GAS IN “RICH” MDEA TO V303 MP FLASH DRUM MDEA TANK T301 H2S Absorption E306 COOLER LV112 SDV104 PV & FV101
- 17. MDEA Methyl Di Ethanol Amine + H2S MDEA-H, HS + - Amino Hydro Sulphide High Press. Low Temp Absorption : Regeneration : MDEA-H, HS Low Press. High Temp MDEA Methyl Di Ethanol Amine + H2S + -
- 18. • MDEA reacts instantaneously with H2S • H2S reacts to yield Hydro sulphide by proton transfer. • H2S + Amine(R2NH2) HS- + (Amine) H+ • CO2 can only react if it dissolves in water to form bicarbonate ion. • Then this ion undergoes acid-base reaction with the amine to yield H2O + CO2 H2CO3 & CO2 + HO- HCO3- • These acids then react with amine to form amine bicarbonate (HCO3-, RNH2+) and amine carbonate. CO2 + H2O + R2NCH3 R2NCH4+ + HCO3- (Slow reaction)
- 19. H2S reacts to give amine hydrosulfide: 1. H2S + R2NH ↔ HS - , R2NH2+ CO2 can react directly with amine to form an amine carbonate: 2. CO2 + 2R2NH ↔ R2NCOO-, R2NH2+ 3. CO2 + H2O ↔ H2CO3 4. CO2 + HO- ↔ HCO3- 5. These acids then react with the amine to form amine bicarbonate (HCO3,- RNH2+) and amine carbonate (CO2, (R2NH2+)2).
- 20. The overall reaction depends upon contact time.Contact time depends on……… • The gas flow rate • The liquid height above plate area (Weir height) • Number of active trays • Only parameter that can be varied is the number of active trays.
- 21. PV218 PV216 TO FLARE TO FUEL GAS HEADER LV215 FV205 ‘LEAN’ AMINE “RICH” MDEA TO V303 MP FLASH DRUM C303 COL. MP FLASH DRUM V303 TO C302 TC558 E302 A/B COOLER REGENERATED AMINE FROM C302 E301A/B PHE TO TANK 301
- 23. ACID GAS OUT V304 REFLUX KOD REGENERATOR COLUMN C302 SOUR GAS IN E303 COOLER SOUR GAS IN “RICH” MDEA FROM V303 THRU’ E301 PV326 PV327 TO FLARE P304A/B TO SRU LV330 LV327 SDV309 E304 REBOILER REGENERATED AMINE TO TANK
- 24. REBOILERS Kettle-type Reboiler Heat Exchanger Model
- 25. H2S C1 C2 C3 iC4 nC4 iC5 CO2 6800 to 6900 1.48 0.2 .02 .02 .03 .16 98.25
- 27. • Precoat filter is designed to filter solids such as iron sulphides & iron carbonates • V311 holds a bed of charcoal as part of filtration package • Then the stream (20% of the total MDEA flow in the system) passes thru’ activated charcoal filter removing odour, impurities, colour & hydrocarbon. • X 301 & X302 are precoat & cartridge type filters • Then the cartridge takes any entrained micro solids
- 28. LL103 ANTIFOAM TANK V361 (Dimethylpolysiloxanic oil) FUEL GAS BLANKETP361A/B LL301 FLARE GAS LH302 TO FLARE P362A/B FLARE GAS KOD V362 TO SLOP TANK FUEL GAS FROM C303 FUEL GAS KOD V363 FUEL GAS LV403 PV601 METHANOL TANK LH602 LL602 P363A/B ANTIFOAM RETURN FUEL GAS FROM C303
- 29. LHH224 LLL109 PB101 LL111 SOV1104 LLL109 PB101 LL111 SOV1101 SOV1102 PB101 SOV1318 (PV327) SOV1216 (PV216) SOV1317 (FV309) P303A/B ST MP FL DRM V303 C301 ABSORBER C301 BTM SDV104 I/L SDV
- 30. LL334 P304A/B ST LLL109 PB101 LL111 SOV1205 SOV1206 P301A P301B SOV1309 (FV309) LL335 P305 ST PB121 PL561 AB-BYPASS SWITCH FL104 SOV1205 LL549 LH110 LH219 PB111 PB112 LL329 PB118 V304 REF DRM V305 SUMP (PANEL PUSH BUTTON) T301 TANK ABSORBER O/L KOD V302 C302 REG CLMN (UNLATCHING SWITCH)
- 31. EQUIP DETAIL SOUR GAS HEATER E305 SOUR GAS KOD V301 ABSORBE R COLMN C301 FUEL GAS STRIPPER C303 RICH AMINE FLASH DRUM V303 SWEET GAS COOLER E306 FLARE GAS HEATER E307 LEAN AMINE STORAGE TANK T301 DUTY 4.655 X 1.1 MM KCAL/H NA NA NA NA 0.778 X 1.1 MM KCAL/H 0.905 X 1.1 MM KCAL/H NA DIMENSIO N (MM) NA 3300 DIA X 4850TL 31OO OD X 11850 H 510 DIA X 4000 H 2200 DIA X 6000TL NA NA 6000 DIA X 9000 H DESIGN PRESSUR EKG/CM2 NA 83 83 10 10 NA NA ATM DESIGN TEMP DEGREE CELSIUS NA 49 75 75 75 NA NA 60
- 32. EQUIP DETAIL TREATED GAS KOD V302 KETTLE TYPE REBOILER E304 REGEN. COL. C302 FUEL GAS STRIPPER C303 PLATE TYP AMINE- AMINE EX. E301A/B OVERHEAD CONDSR E303 REFLUX DRUM V304 LEAN AMINE COOLER E302A/B DUTY NA 13.77 X 1.2MM KCAL/H NA NA 7.96X 1.1 MMCAL/H 6.91 MMCAL/H NA 5.14 X 1.1 MM KCAL/HR DIMENSION (MM) 3300 DIA X 4200H NA 2900 OD X 19150 H 510 DIA X 4000 H NA NA 1400X 3000H NA DESIGN PRESSURE KG/CM2 82.05 (S/T): 6.5XFV/9X FV KG/CM2G 6.5 & VACUUM 10 NA (S/T): 6.5 FV/7.5 6.5 & FV (S/T): 6.5/7.5 DESIGN TEMP DEGREE CELSIUS 53 (S/T): 144/200 195 75 NA (S/T): 127/58 95 (S/T): 88/58
- 34. Adsorption is the process of removing impurities from a gas stream by means of a solid material called adsorbent that has special attraction for the impurities.
- 35. • Chemical Formula: HO(C2H4O)3H • Adsorbs water from the Gas until the equilibrium partial pressure of TEG & water in the gas is reached. • Bonding with water forms H-OH HO-CH2-CH2-O-CH2-CH2-OCH2-CH2-OH • Results achieved-1 to 2% of moisture by wt in the outlet
- 36. HO ( C2 H4 O )3 H Triethylene Glycol (TEG) H2O RICH TEG Adsorption at High Press Low Temp H2O Regeneration at Low Press High Temp
- 37. PHASE I TRAIN # PHASE II PHASE III PHASE III A CAPACITY 41 42 43 44 45 46 47 5.7 MMSCMD each 5.7 MMSCMD each 5.7 MMSCMD each 6.3 MMSCMD each
- 38. P401A/B, DOUBLE ACTING RECIPROCATING PUMP V404 INLET KOD GAS OUT V401 OUTLET KOD SWEET GAS TO DPD SWEET GAS FROM GSU ABSORBER COLUMN C401 TRAY 1 TO 9 “RICH” TEG LV106 SDV104 PV & FV101 SURGE DRUM V403 REGENERATED TEG FROM E401 E403 COOLER
- 40. E402 REBOILER VAPOUR VENT TV215 FUEL GAS FOR STRIPPING (FT202) TO SURGE DRUM V403 C403 E401 PHE HP STEAM DEGASSERDRUM V402 CHARCAOLBED LV116 CATRIDGE FILTER FUELGAS ‘RICH’TEGFROMC401 C402 REGEN
- 41. • The relatively cool TEG from C401 bottom does two things; • One, it brings down the temperature of the vapour leaving the C402 top thru’ three way valve • Two, the other stream goes into the plate heat exchanger E401 to cool the regenerated glycol before going into V303 and in turn getting itself heated upto 145 deg before entering C402 having 4 bubble cap trays. • TV 212 controls the temp of reboiler where the TEG at 185 deg overflows into the attached C403 end mounted on the side of the reboiler. C403 is a packed column where the hot fuel gas from V401/402 preheated inside a 2nd coil in E402, strips the glycol of remaining moisture to achieve 99.7% purity. • This stripped glycol comes in contact at E401 with the cooler rich TEG from C401 & reaches 80-deg. • Stripper gas is piped into E402 & V403 to maintain +ve pressure. • The reciprocating TEG pumps attached to V403 completes the cycle of pumping TEG into the column C401.
- 42. LLL105 FL106 PB101 SOV1103 LL218 PB106 P403 ST LLL105 FL106 PB101 SOV1101 LLL105 FL106 PB101 P401A/B STOP LLL105 PB101 SOV1102 LLL133 PB101 SOV1105 THH210 PB101 SOV1212 (TV212) LLL132 PB101 SOV1104 C401 ABSORBER TEG FLOWLOW SWITCH V404 I/L KOD V401 DRYGAS SCRUBBER E402 REBOILER TEMP SUMP V405 I/L SDV O/L SDV C401 BOTTOM
- 43. EQUIP DETAIL FEED GAS KOD V404 GLYCOL ABSORBER COLUMN C401 DRIED GAS SCRUBBER V401 RICH GLY DEGASSIN G DRUM V402 LEAN GLY TRIM COOLER E403 DUTY NA NA NA NA 0.164X1.2MM KCAL/H DIMENSION (MM) 3300 DIA X 3250H 2800 DIA X 9000H 3600 DIDX 4200H 1100 DIA X 3250H 2200 DIA X 6000TL DESGN PRESSUREK G/CM2 81.4 81.4 81.06 10 (S/T): 7.5/ 82 DESIGN TEMP DEGREE CELSIUS 55 60 60 55 (S/T): 60/120
- 44. EQUIP DETAIL GLYCOL STRIPPG COLUMN C403 GLYCOL REG. C402 LEAN GLYCOL SURGE DRUM V403 LEAN GLYCOL TANK T401 GLY-GLY HEAT EXCH. E401A/B RICH GLYCOL REBOILER E402 DUTY NA NA NA NA 0.627X1.2M M KCAL/H 0.625X1.2 MM KCAL/H DIMENSION (MM) 500 DIAX 2150H 600DX 4200L (UPPER) 800X2590 (LOWER) 1000 DIA X 4000L 4500 DIA X 3000H NA NA DESGN PRESSURE KG/CM2 1.1 1.1 1.1 ATM (S/T): 1.0/ 39 (S/T): 1.0/ 39 & FV DESIGN TEMP DEGREE CELSIUS 240 220(TOP) 240(BTM) 240 60 (S/T): 240/220 (S/T): 240/260
- 45. The incoming sour gas is treated by washing/scrubbing with aqueous solution MDEA (Methyldiethanolamine). Selectively removing H2S from 1375ppm (max) down to 4ppm & limiting CO2 co absorption to max of 32%. Processing Acid Gas at SRU for Sulphur Removal. Removing moisture, entrained or enriched during sweetening, in Gas Dehydration Unit with TEG upto -46 deg celsius.