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
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
11.
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
13.
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
16.
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
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
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
33.
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
39.
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.
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.
