Embed Size (px)
Citation preview
EE--STRSTRTMTM Technology DevelopmentTechnology Development for for Lignite GasificationLignite Gasification
Albert Tsang, E-Gas Technology Director Cliff Keeler, E-Gas Product Manager
Gasification Technologies Conference Washington, D.C. November 3, 2010
2
E-STRTM Technology -- Business Objectives
• Provide an economically attractive process for lower rank coals
• Low CAPEX & OPEX
• Operate at pipeline pressure for SNG
• High reliability
3
Gasification Opportunities for Low Rank Coal
4
Syngas
SyngasCooler
Slurry/Gas/Water
O2
Slag
Char
ResidenceVessel
Slurry
Current E-GasTM Gasifier
• Slurry feed with unique two stage design
• Improves conversion efficiency, esp. for reactive fuels
• Dry recycle maintains high conversion for low reactivity fuels
• Allows customization to match the syngas applications
• Flexible slurry / water / gas quench to 2nd stage
• Flexible CH4 concentration
5
E-STR Technology - Basic Concept
• More coal slurry to 2nd stage and less to 1st stage – Reduces O2
consumption– Increases Cold
Gas Efficiency
• Managing tar/liquid production or destruction is key
IMPROVED COLD GAS EFFICIENCY
SLURRY TO SECOND STAGE
COLD
GAS
EFF
ICIE
NCY
REDUCED OXYGEN CONSUMPTION
SLURRY TO SECOND STAGE
OXY
GEN
CO
NSUM
PTIO
N
6
Syngas
Syngas Cooler
O2
Char
Residence Vessel
Char
Slurry
Slag
Syngas
Syngas Cooler
Residence Vessel
O2
Char
Slurry
Slag
Syngas
Syngas Cooler
Residence Vessel
Dry feed 1st stage
Cylindrical for Hi-
pressure
Catalytic tar conversion &
CO shift
E-STR Gasifier Configuration
No syngas cooler
No residence
vessel
Up to 100% slurry to 2nd
stage
Lower temp 2nd stage, 400-
750C
INTERNAL FEEDSTOCK UPGRADER
7
Syngas
O2
CharChar
Slurry
Slag
Syngas
O2
Char
Slurry
Slag
Syngas
E-STR Gasifier Configuration
• Simple Design
• High Efficiency
• High Pressure
8
E-STR Technology Advantages• Reduced CAPEX
– Elimination of Residence Vessel and Syngas Cooler– Up to 40% smaller ASU from dry feeding 1st stage– Up to 20% smaller downstream systems due to higher syngas
and methane yield from gasifier– Low cost slurry-based feed system; dry solid recycle to 1st stage
with no lock-hoppers
• Reduced OPEX– Lower fuel and oxygen consumption– Lower maintenance cost
• Improved Operability– Less equipment; simpler design– Simple and reliable slurry-based feed system– High pressure cylindrical gasifier design and slurry-based feed
system allows delivery of SNG at pipeline pressure without added compressors
9
• Concept conceived in early 2000’s
• Bench-scale gasifier testing conducted in 2007
• Pilot gasifier testing conducted in 2008
• Bench scale catalytic tar development complete; slipstream testing in progress
Chronology of E-STR Technology Development
Bench-Scale 2nd Stage Gasifier
10
Coal Fuels Evaluated in Pilot Tests
• Bituminous coal
• Subbituminous coal
• Lignite coal
• All slurry-fed
• 20 different process conditions tested
Two Stage Pilot Gasifier
11
Data from Bench-Scale and Pilot Studies
• Gasification performance matrix includes:– Gasifier temperatures– Amount of slurry feed– Residence time– Coal rank
• Reaction kinetics and product distribution at various operating conditions– Reactivity – coal conversions– Byproduct production - Tar, BTX, CH4
– Water-gas-shift, syngas composition, etc.
12
Tar Management
• Tar production expected but much less than in fixed bed gasifiers
• Varies with 2nd stage temperature, process configuration, and coal rank
• Syngas temperatures exiting gasifier too low for thermal degradation of tars
• Current catalysts for tar cracking require temp >800C
• ConocoPhillips has successfully developed low temperature tar conversion catalysts
13
Tar Conversion Catalyst Development
• 100% tar conversion• Good catalyst activity with
no deactivation observed in the lab
500 psig, simulated syngas
0
20
40
60
80
100
0 3000 6000 9000 12000 15000
Time-On-Stream (min)
Nap
htha
lene
con
vers
ion
(%)
14
Low Temperature Catalytic Tar Conversion
Reaction Temp (deg C)
TarConversion
(%)Inlet H2 /CO Outlet H2 /CO
400 100 0.7 3.50
• Good activity for destroying tars at low temperatures in the presence of H2 S
• Potential to customize the catalyst for other reactions:• Water-Gas-Shift (WGS)• Methanation
• Potentially eliminates downstream WGS reactor
15
Catalytic Tar Conversion Slipstream Unit
• Slipstream unit assembled• Extended catalyst testing in
syngas slipstream planned at Wabash
16
Case Study – Lignite-to-SNG with E-STR Technology
DRY CHAR REMOVAL
CATALYTIC TAR
CONVERSION
SYNGAS CLEANING/
CONDITIONING
SLURRYPREPARATION
METHANATION
WATER
COAL
SLURRY
OXYGEN
SYNGAS
CHAR RECYCLE
SYNGAS SYNGASPRODUCT SYNGAS
SLAG
SNG TO PIPELINE
E-STR PROCESSCO2
ASU
Block Flow Diagram
TWO STAGE
GASIFIER
17
E-STR Process - Expected Syngas Composition Comparison
E-Gas E-STR(after Tar
Conversion)
H2 /CO 1.1 4.4
CH4 3.5% 4.4%
Tars 0-2 ppm 0-2 ppm
For a Lignite coal feed45% solid concentration in slurry
18
Comparison with Other Gasification Processes
For Lignite-to-SNG :
SNG yield based on E-STR Technology is comparable to Fixed Bed Gasifier processes
Significantly reduced capital cost for SNG plant
smaller ASU elimination of heat recoverysmaller downstream equipment
No oily wastewater
19
Patenting Status for E-STR Technology
U.S. and foreign patent applications submitted for :
• E-STR process and process configurations
• Low temperature tar conversion catalysts
20
SUMMARY
• Encouraging test results for E-STR Technology
• Efficient & economic conversion opportunity for low rank coals
• Evaluating sites, both domestic & international, for demonstration plant
