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International Conference on
“Refining Challenges & Way Forward”
April 16-17, 2012
Shangri-La's - Eros Hotel, 19 Ashoka Road,
New Delhi
Asha Masohan
INDIAN INSTITUTE OF PETROLEUM
Introduction
Regenerative process
Developmental studies @ IIP/EIL
Refinery applications:
A new paradigm
IIP on the frontier of acid gas treating
Introduction
Regenerative process
Developmental studies @ iip/eil
Refinery applications:
A new paradigm
IIP on the frontier of acid gas treating
Hazards of SO2 Emission
Gaseous SO2 : Highly toxic
◦ Adverse health effects
5-10 ppmv : Irritation of respiratory tract
400-500 ppmv: Dangerous to life
◦ Adverse environmental effects
Acid rains
Global SO2 emission by primary source
Global sweet sour crude production D
ail
y P
ro
du
cti
on
(M
BP
D)
Gradual Global Trend Towards Heavier and Higher Sulphur Crude
Sulfur production at petroleum refineries has increased at a faster rate than the refineries have increased input.
UNIT SO2 EMISSION, (Kg/day)
Crude distillation
#AU-1 419.28
#AU-2 418.8
#AU-3 238.8
#AU-4 1109.52
Vacuum distillation
#VDU 187.2
#FPU-1 537.84
FPU-2 622.08
Hydrocracking 732
Cat Reforming 131.28
Visbreaking 496.8
Sulphur recovery 1488
FCC 25.68
CO-Boiler 4725.6
TPS Utility block
#TPS 1849.68
#CGP 0
TOTAL 12982.56
Introduction
Regenerative process
Developmental studies @ iip/eil
Refinery applications:
A new paradigm
IIP on the frontier of acid gas treating
Advantages of Amine-based Regenerative FGD Technology
Regenerative process highly selective for SO2
Similar to conventional amine treating
Equipment/process design completely conventional
Absorbent: an aqueous solution of highly stable amine, not affected by oxygen
Absorbent has no vapour pressure
SO2 out is 25-100 ppm regardless of inlet concentration
The only waste effluents are the acids, particulates and very small acid flow from HSS removal
SO2 byproduct: a high value commodity or converted to sulfur or H2SO4
Process Flow Sheet
SO2 + H2O H+ + HSO3-
HSO3- H+ + SO3
- -
R1R2R3B R1R2R3BH+
Unique absorbent
B B X- X-
BH+ B BH+ BH+ HSO3-
Pure water saturated SO2 after regn.
Introduction
Regenerative process
Developmental studies @ IIP/EIL
Refinery applications:
A new paradigm
IIP on the frontier of acid gas treating
Solvent screening: Selection of solvent (in 1 and 2 molar solvents at 25 AND 50oc)
Absorption/regeneration data
Pure SO2
SO2-N2 mixtures
CO2-SO2-N2mixtures
Ph titrations for pka1 and pka2 estimations Regenerability tested for amount of SO2 recoverable from tested solvents Degradation studies Cost analysis Final recommendations
Steps In Solvent Selection
Liquid
outlet
Stirrer Motor
N2
SO2
CO2
Needle valve
NRV
Capillary manometer
SS/glass/Silicon tubing
Sweet Gas outlet (for analysis
Feed gas Analysis
Three way valve
Three Way
Soap bubble for flow rate
or GC
Gas inlet
Gas Phase
Liquid Phase Water
in
LABORATORY SET UP
All measurements in cm
8 10 6 6
7.2
7.2 7.2
N2
CO2
SO2
Operating variables studied:
Effect of:
pH
Temperature
Solvent concentration
0
2
4
6
8
10
0 2 4 6 8 10
SO
2 a
bso
rbed
, g
m
pH
Effect of pH on SO2 absorption
1.00
1.05
1.10
1.15
1.20
1.25
1.30
25 45 65
SO
2 a
bso
rbed
, m
ole
s/m
ole
p
iper
azi
ne
Temperature, oC
Effect of temperature on absorption
0.00
0.30
0.60
0.90
0 10 20 30
SO
2 m
ole
s/m
ole
Amine concentration, %
Effect of amine concentration on SO2
absorption
Absorption studies Effect of molecular structure of solvent
0
2
4
6
8
10
0 500
SO
2 a
bso
rbd
, gm
Time, min.
Absorption behaviour of SO2 in solvents for SO2-N2 mixture with /
without CO2
SHORTLISTING OF AMINES
Amine Abs. Reg. % Reg. Time Time
(amine) (am Slt)
AGSL 1 ~ ~
AGSL 2 ~
AGSL 3
AGSL 4 ~
AGSL 6 # ~ ## ##
AGSL 7
AGSL 8
AGSL 9 # ~ # ~
AGSL 10 # ~ # ~
AGSL 11 ~
AGSL 12 ~ x x
AGSL 13
AGSL 14
0.00
2.00
4.00
6.00
8.00
10.00
12.00
0 200 400 600 800
SO
2 A
bso
rb
d,
gm
Time, min
Absorption Behaviour of Solvent for SO2 and SO2-CO2 Mixtures of N2
SO2 CO2 - SO2
0
5000
10000
15000
20000
25000
30000
35000
40000
0
100
200
300
400
500
600
700
SO
2,
pp
m
Time, min
CO2 and SO2 analysis by GC (SO2 - CO2 - N2 mixture)
so2 co2
CO2, ppm
0
0.5
1
1.5
2
2.5
SO
2 m
ole
s/m
ole
am
ine
Amine
Abs-Regn Behaviour of 4 shortlisted solvents
SO2 absorbed
SO2 in regentd amine
SO2 recovered
SOLVENT LOADING DURING ABSORPTN. REGEN.(moles/mole)
SOLVENT START 1ST CYCLE 2ND CYCLE 3RD CYCLE 4TH CYCLE
min. max. min. max. min. max. min. max. min. max.
Solv. A 0 2 1.5 0.6 2.24 1.4 0.8 2.4 1.8 0.7 2.6 1.2 1.4
Solv. B 0 2.2 1.5 0.8 2.14 1.7 0.4 2.4 1.7 0.7 2.5 1.6 0.9
Solv. C 0 2 1.4 0.6 1.97 1.9 0.1 2.3 1.7 0.7 2.5
Solv. D 0 2.1 1.7 0.3 2.29 1.7 0.6 2.2 1.8 0.5 2.4 2 0.4
Solv. E 0 2.1 1.7 0.4 2.16 1.6 0.5 2.3
Total Data Points For Absorption - Regeneration
DATA POINTS No. OF AMINES STUDIED 12 PURE SO2
1 Molar 12 2 Molar 12
SO2-N2 MIXTURE AT 50oC 12 AT 25oC 12
CO2-SO2-N2 MIXTURE 18 CYCLICITY EXPERIMENTS 6*4
TOTAL DATA POINTS 90
◦ 200mm dia column (SS304)
◦ Thermosiphon reboiler
◦ 1.5m tall bed of structured packing
◦ 99.9% purity N2 from N2 PSA plant
◦ Pure SO2 from cylinders
◦ 10wt% solvent
•Summary
• Regenerative SO2 Removal Process Developed
• Solvent formulation identified
• VLE data for solvent generated
• Process models developed
• Processing scheme and Process conditions
identified
• HSS formation inhibitors identified
Introduction
Regenerative process
Developmental studies @ iip/eil
Refinery applications:
A new paradigm
IIP on the frontier of acid gas treating
Fuel fired in furnaces /boilers
59% FCC units
15%
Sulphur Recovery
Units 11%
Flares 5% Miscellaneous
11%
Percentage of refinery SO2 emissions
Thermal
Stage
3rd Catalytic Stage
Waste Heat Boiler
2nd Catalytic Stage
Incinerator
Sulfur Condenser
1st Catalytic Stage
Gas Cooler
SOR
System Scrubber
Regenerator
Treated Tail Gas To Stack
Air + Fuel
Rich Solvent
Lean Solvent
SO2
S
Air
Acid Gas
S S
Claus Unit with Regn. SOR System TGTU
S
vs
Thermal
Stage
3rd Catalytic Stage
Waste Heat Boiler
2nd Catalytic Stage
Incinerator
Sulfur Condenser
1st Catalytic Stage
Gas Cooler
SOR
System Scrubber
Regenerator
Treated Tail Gas To Stack
Rich Solvent
Lean Solvent
SO2
S
Air
Acid Gas
S S
Claus Unit Debottlenecking with CANSOLV System Unit
S
Air
Acid Gas
Sour Water Stripper Gas
Heater
Incinerator
1st Catalytic Stage
Waste Heat Boiler
2nd Catalytic Stage
Gas Cooler
SOR
System Scrubber
Regenerator
Treated Tail Gas
Rich Solvent
Lean Solvent
SO2
Regn. SOR System SRU
S S
To Stack
Acid Gas
Air
Sour Water Stripper Gas
FCC REACTION
II.DS.
CRUDE
UNIT
GAS PLANT
SOLVENT REGEN.
SRU CATALYTIC STAGES
FCC REGEN
COGEN UNIT
BOILER
OXIDISED SULFUR - SO2 SCRUBBING
REDUCED SULFUR - H2S SCRUBBING
SO2
TAIL GAS
SULFUR
H2S BYPASS
RICH SOR SOLVENT
RICH AMINE
H2S
SOR REGENERATOR
Reduction of significant SO2 emission
Simplifies treating SWS gas
Improves relliability and capacity of existing SRU
Expensive TGTU eliminated
Revolutionise the strategy for overall refinery sulfur abatement
Attractive alternative to cuastic scrubbing of FCCU off-gas
Regenerative
SO2 as valuable byproduct
◦ Sulphur
◦ H2SO4
No problem of land filling with solid waste disposal
Standard equipment and engineering
Low cost sensitivity of SO2 concentration
SO2 removal to <10ppm if desired
Minimum effluents
Competitive economics
Refinery infrastructure favours such process
LP steam: main energy source
Minor extension required in existing Claus plants
Regeneration unit locally separable from absorption unit
Large body of knowledge available through acid gas treatment
@ Minimum development time
Control of sulphur emission from:
Oil refining
SRUs
Cogeneration units
Power plant boilers
FCCU
Natural gas processing
Smelting
Pulp and paper
Process costs with such technology only
Weakly sensitive. High sulphur low value
fuels (Petroleum coke & visbreaker vacuum
Residue) can be burnt enomically
Introduction
Regenerative process
Developmental studies @ iip/eil
Refinery applications:
A new paradigm
IIP on the frontier of acid gas treating
Process for SO2 removal from flue gas streams
EIL-IIP-NRL
Porcess for removal of Hydrogen sulphide (H2S) from sour gas stream:
IIP-KRL ◦ A novel catalyst formulation with promotor for
enhanced regeneration ◦ Reduces H2S down to <4ppm
Process for recovery of Carbon dioxide from flue gas stream;
Min. Fertilizers
◦ Novel solvent CO2SOL-10
Innovations on use of solids with absorbents
Unit for Lab Studies Automated Unit for absorption / regeneration and kinetic studies
All glass continuous unit
Auto-titrator Metrohm Ion Exchange Chromatograph
director@iip.res.in
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