“Gasification 101”
Steve Jenkins
CH2M HILL
Gasification Technologies Council Workshop
March 13, 2008
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Topics
• Gasification and IGCC “101”
• History of modern coal gasification and IGCC
• Technologies
• Environmental issues
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What is Gasification?
Fuels
Chemicals
Power
Syngas
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What is Gasification?
•Thermal conversion of coal at 1,400-2,800°F,
with a limited supply of air or oxygen, into a
synthetic gas, or syngas
• It’s not combustion!
• Gasification uses only a fraction of the oxygen that would be needed to burn the coal
– Combustion: excess air
– Gasification: air starved
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Combustion
C + O2 → CO2
Combustion of coal produces CO2 and
heat, which is used to produce steam for power generation
in a steam turbine generator
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Gasification
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Main Gasification Reactions
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What’s in the Syngas?
• Syngas contains mostly hydrogen, carbon
monoxide, water vapor, carbon dioxide, and
methane
• Syngas can be used as a fuel to generate power,
or to make chemicals & fuels
• Heating value is 250 Btu/scf (1/4 of natural gas)
– Air-blown gasifier syngas includes a large amount of
nitrogen, and has a heating value of about 125 Btu/scf
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How has Gasification been Used?
• Making “town gas” from coal (1792)
• Manufactured gas plants – prior to discovery and use of natural gas
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How has Gasification been Used?
• Fuels
– WWII: Germany – no access to oil, but lots of coal
– “Fischer-Tropsch” process produced diesel and gasoline from syngas
– Cars and trucks used small wood gasifiers for fuel
wood gasifier
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Modern Coal Gasification
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Modern Coal Gasification
95% pure
oxygen
Source: Eastman Chemical
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SASOL
• Located in South Africa
• Started up in 1955
• Lurgi gasifiers (97)
• Fischer-Tropsch process converts syngas to liquid fuels
• Now gasifies 90,000 tons coal/day into 150,000 barrels/day of liquid fuels
Source: SASOL
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Eastman Chemical - Kingsport, Tennessee
• “Coal-to-Chemicals” Facility
• Started up in 1983
• Originally part of Eastman Kodak
• Texaco (GE) gasifiers
• Gasifies 1,300 TPD Central Appalachian medium sulfur coal
• Sulfur compounds and ash are removed from the syngas
• Syngas is used to make methanol, acetic acid, acetic anhydride, methyl acetate… and
Source: Eastman Chemical
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Consumer Products
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Dakota Gasification CompanyGreat Plains Synfuels Plant
• Beulah, North Dakota
• Part of Basin Electric Power Cooperative
• Started up in 1984
• Converts 16,000 tons/day
of North Dakota lignite to:
– Synthetic natural gas
– Fertilizers
– Chemicals
Source: Dakota Gasification
Source: Dakota Gasification
Source: Dakota Gasification
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Coffeyville ResourcesCoal to Fertilizer
• Ammonia/fertilizer plant in Kansas
• Used high-cost natural gas to make hydrogen for ammonia
• Added pet coke gasification system
– GE Energy (Texaco) gasifier
– Produces syngas with high H2 content
– H2 is used to make ammonia
– Significant production cost savings and increased profitability
Source: Coffeyville Resources
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Gasification Plants
• There are 142 operating gasification plants (not IGCC plants) with a total of 420 gasifiers in operation worldwide
• They are used primarily for gasifying coal, pet coke, natural gas, and refinery wastes
• They produce syngas for use in making chemicals, synthetic natural gas, hydrogen for ammonia, Fischer-Tropsch transportation fuels, and some power
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Proposed Gasification Plants
• 25-35 projects across North America
• Drivers
– High cost of natural gas where it is the feedstock for downstream products
– Production of lower cost transportation fuels
– Syngas or SNG to replace high-cost natural gas
– High cost of power: self-generation
– Low-cost, available feedstocks
– Federal and state incentives
• Energy Policy Act of 2005
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Proposed Gasification Plants
• Feedstocks include
– Coal
– Pet coke
– Refinery waste streams
– Biomass
– Blends
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Proposed Gasification Plants
• Products include:
– Ammonia
– Fischer-Tropsch fuels (diesel, naphtha)
– Hydrogen
– Methanol
– Methyl acetate
– SNG
– Urea
– Urea Ammonium NitrateSources: Rentech, Coffeyville Resources
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Combined Cycle Power Generation
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What is Simple Cycle Power Generation?
• Simple cycle combustion turbine burns a fuel
– Fuel oil
– Natural gas
– Biogas
– Jet fuel
• Combustion turbine turns a generator, producing electricity
• Hot exhaust gas (>1,000 °F) exits though a stack
• Efficiency = ~35%
Source: Siemens
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What is Combined Cycle Power Generation?
• Hot exhaust gas from gas turbine is ducted through a boiler, where steam is produced
• Steam is piped to a conventional steam turbine-generator, producing more electricity
• Combined cycle plant efficiency = 55+%
• Commercially proven at hundreds of installations
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Combined Cycle – 2 Gas Turbines and 1 Steam Turbine
Source: Calpine
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How Does IGCC Work?
• Integrate the coal gasification process with a combined
cycle power plant
• Instead of using natural gas or fuel oil in the combined
cycle power plant, convert low-cost coal to a clean-
burning syngas and use it as a fuel
• Advantages of IGCC
– Can be designed to use a wide range of feedstocks
– Takes advantage of high efficiency combined cycle power generation technology
– Has low emissions and saleable byproducts
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IGCC
Combined Cycle
Power Plant
Gasification Plant
Source: DOE
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Where has IGCC Been Demonstrated?
MHIcoalNakoso, JapanClean Coal Power R&D
Co.
Multiple Japanese
Utilities; MITI; CRIEPI
Prenflocoal/cokePuertollano,
SpainPuertollanoELCOGAS
GE Energycoal/cokeMulberry, FLPolk Power
StationTampa Electric
ConocoPhillipscoal/cokeW. Terre Haute, IN
Wabash RiverSG Solutions
Shellcoal/biomassBuggenum, Netherlands
Willem Alexander Centrale
Nuon
Gasifier Technology
FeedstockLocationFacilityCompany
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Nuon Willem-Alexander CentraleBuggenum, The Netherlands
• Started up in 1993
• Shell technology
• 2,000 tons/day coal
• 253 MW net
Source: Nuon
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SG SolutionsWabash River Generating StationW. Terre Haute, IN
• Started up in July 1995
• ConocoPhillips E-Gas™technology
• 2,000 tons/day coal, pet coke, blends
• Repowered existing unit
• DOE Clean Coal Technology Program
• 262 MW net output
Source: ConocoPhillips
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Tampa Electric CompanyPolk Power StationMulberry, FL
• Started up in July 1996
• GE Energy gasifier
• 2,000 tons/day coal and blend with pet coke
• DOE Clean Coal Technology Program
• 252 MW net outputSource: TECO
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C o a l
250 0 T P D
R o d M i ll
W a te r
S lu rr y
T a n k
S lu rr y
Pu m p
M ain A ir
C om p ress or
32 M W
P ro d u c t
C o m p re ss o r s
1 8 M W
O x yg e n
210 0 T P D
C o a l/W a te r
S lu r ry
C o ld
B o x
D ry e r s
L o ck h o p p e r
S la g &
W a te r
F lya sh
& W a te r
Co m p resso r T ur b in e
C o m b u s to r
G e n e ra to r
1 9 2 M W
C le a n
S ta ck
G a sA ir
C o n d e n se r
C o n d e n sa te
P u mp
1 6 0 0 p s ig
S a tu r a te d
S te a m
C le a n S yn ga s
W a te r Sc r u b b e r
D i lu e n t N it ro g e n
5 8 0 0 T P D
R a d ia nt
Sy n ga s
C o o le r
G a s if ie r
C o n v e c t ive
Syn g a s
C o o le r
F ina l F ilte r
C o o l in g
W a te r
M D E A Ac id G a s R e m o va l
Ac id G a s
H 2S + C O 2
T o S u lfu ric
A c id P la n t
C o o l in g
W a te r
55 ps ig
S team
E c o n o m iz e d
B o i le r
F e e d w a te r
B F W Pu m p
H e a t R e c o ve ry
St e a m G e n e ra to r
(H R S G )
G e n e ra to r
1 2 5 M W
Ste a m T u r b in e
R a w
Syn g a s
C O S
H yd ro ly s is(C O S H 2S )
F ly as h &
C h lo r id e
R e m o v a l
Source: TECO
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ELCOGASPuertollano, Spain
• Started up in 1998
• Prenflo technology (modified Shell)
• ~2,000 tons/day of 50/50 blend of local subbituminous coal and pet coke
• 260-280 MW net
Source: Elcogas
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Clean Coal Power R&D Co.Nakoso, Japan
• Started up in late 2007
• MHI technology
• ~1,700 tons/day of subbituminous coal
• 250 MW net
Source: MHI
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Gasification Technologies for IGCC
GE
ConocoPhillips
E-Gas
ShellSiemens
MHI
KBR
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ConocoPhillips (E-Gas™ process)
• Coal-water slurry feed
• Oxygen-blown
• Refractory-lined gasifier
• Good for a wide range of coals, from pet coke to PRB, and blends
Source: ConocoPhillips
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GE Energy
• Coal-water slurry feed
• Oxygen-blown
• Refractory-lined gasifier
• Good for bituminous coal, pet coke, or blends of pet coke with low-rank coals
• Developing dry-feed gasifier for use with low-rank coals
Sources: GE, DOE
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Kellogg Brown & Root (KBR)
• Dry feed
• Air-blown transport reactor
• Pilot tested on wide range of coals at Power Systems Development Facility in Alabama
• Targets low-rank coals
• Mississippi Power Co. to develop full-scale 560 MW plant
– LigniteSource: Southern Company
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Mitsubishi Heavy Industries (MHI)
• Dry feed
• Air-blown
• Good for low rank coals
• 250 MW demonstration plant started up in Japan in November 2007
• Reached full load on syngas last week
Source: MHIl
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Shell
• Dry feed (coal is crushed and dried and then fed into gasifier)
• Oxygen-blown
• Waterwall in gasifier
• Good for wide variety of feedstocks, from pet coke to PRB
Source: Shell
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Siemens Fuel Gas
• Dry feed
• Oxygen-blown
• Waterwall screen in gasifier
• Good for a wide variety of feedstocks, from bituminous to low-rank coals
Source: Siemens
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Proposed IGCC Projects (air permits final or in review)
In ReviewKBRLigniteLiberty, MSKemper CountyMississippi Power
In ReviewConocoPhillipsPRB/Illinois #6/pet coke
Taconite, MNMesabaExcelsior Energy
FinalGECoalTaylorville, ILTaylorville Energy Center
Tenaska/MDL Holdings
FinalGECoalOwensboro, KYCash Creek Generation
MDL Holdings/GE
In ReviewConocoPhillipsPRB/pet cokePort of Kalama, WA
Pacific Mountain Energy Center
EnergyNorthwest
FinalGECoalEdwardsport, INEdwardsportDuke Energy Indiana
In ReviewGECoalOH; WV Great Bend/Mountaineer
AEP
Permit StatusGasification Technology
FeedstockLocationFacilityCompany
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Capacity of Proposed IGCC Facilities
• New IGCC plants based on sufficient syngas to
fully load two “F class” gas turbines
• Gross output: 780 MW
• Internal load: 150 MW (19% of gross output)
• Net output: 630 MW
• Feedstock requirements
– Pet coke: 4,000 tons/day
– Bituminous coal: 6,000 tons/day
– PRB:7,800+ tons/day
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IGCC Availability Improvements
• Lessons learned from 10+ years of experience n
– Materials of construction
– Spare equipment
– Gasifier refractory
– Burner design
• Next generation of IGCC should achieve 85+% availability
– Spare gasifier train may achieve 90% availability
– Back-up fuel can also improve unit’s availability
– Options must be balanced against cost of capital vs. fuel
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Environmental Issues
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Air Emissions
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Technology Comparison
Pre-combustion clean-up of
small volume of syngas
Clean fuel and SCR
Post-combustion clean-up of
large volume of exhaust gas
Emission Emission ControlControl
Syngas in gas turbine
Natural gas in gas turbine
Coal in boilerCombustion Combustion
SyngasNatural gasCoalFuelFuel
Coal--FeedstockFeedstock
IGCCIGCCNGCCNGCCPCPC
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IGCC - a Different Environment Than PC and NGCC
• Gasification occurs in a reducing atmosphere
– sulfur compounds are liberated as H2S
– removed by refinery industry technologies to levels ≥98%
• NOx is controlled by saturating the syngas stream with water or steam (cools the flame) and injecting N2 with syngas (as diluent)
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Comparison of Air Emission Controls: PC vs. IGCC
Pre-sulfided activated
carbon bed
Wet scrubber, high
temperature cyclone,
candle filter
Syngas saturation and
N2 diluent
Acid gas removal absorbs H2S and
COS
IGCCIGCC
Inject activated carbon
ESP or baghouse
Low-NOx burners and SCR
FGD system absorbs
SO2
PCPC
MercuryMercuryPMPMNOxNOxSOSO22
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Air Permitting
• Same coal delivery and handling emission points as PC units
• Same HRSG stack emission points as NGCC
• Air permitting requirements
– Air dispersion modeling
– BACT analysis
– Emission controls
– Fugitive dust controls
• Coal delivery, unloading and handling
– Cooling towers
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New Source Performance Standards
• Final EPA regulations, June 2007
• IGCC is covered as an Electric Utility Steam
Generating Unit, just like PC boilers, if:
“The combined cycle gas turbine is designed
and intended to burn fuels containing 50 percent
(by heat input) or more solid-derived fuel not
meeting the definition of natural gas on a 12-
month rolling average basis”
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Water Issues
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Water Consumption and Liquid Discharge Permits
• Water permits
– Consumptive use permits
• raw water treatment
• reverse osmosis and demineralizer
– State and local permits for potable water treatment and supply systems
– CWA Section 316(b) cooling water intakes
– NPDES permit for stormwater and wastewater discharges
• Zero liquid discharge system can eliminate need for discharge
– Local permits for sanitary sewer discharges or package treatment plants
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• For IGCC reference plant:
– 780 MW (gross) unit, 464 MW is from gas turbines and 316 MW is from the steam turbine
– Only 40% of total output is from steam turbine, so cooling water make-up needs are decreased by ~60%
• No FGD system needed for IGCC, so no need for water to produce limestone slurry
• IGCC can require water for preparing coal slurry and for syngas washing and cooling
Water ConsumptionIGCC vs PC
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Comparison of Water Use
0
10
20
30
40
50
60
70
80
90
100
SCPC
IGCC
% C
om
pa
red
to
S
CP
C
Source: DOE
30% less
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Solid Byproducts
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• Ash is removed in molten form, then quench-cooled to form glassy, inert, saleable slag
Solid Byproducts
Molten slag
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Slag
• Very similar to slag from coal-fired boilers, but….
• It is not regulated as a coal combustion byproduct under RCRA, and does not have the same Bevill exclusion from Subtitle C (hazardous wastes)
• However, gasification slag does have a Bevill exclusion as a mineral processing waste
• Mineral processing wastes, as listed in 40 CFR 261.4(b)(7) include:
– “Gasifier ash from coal gasification”
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Slag Use
• Used for making
– Cement
– Asphalt filler
– Roofing shingles
– Sand-blasting grit
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Other Byproducts
• Sulfur
– Recovered in molten form
– Commercially proven processes from refinery industry
– Transported by rail or truck
• Sulfuric acid
– Commercially proven in many industrial processes
– Transported by rail or truck
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Questions?