A Review of Fluidized Bed Gasification...
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A Review of Fluidized Bed A Review of Fluidized Bed Gasification Technology Gasification Technology Todd Pugsley Todd Pugsley a a and Nader Mahinpey and Nader Mahinpey b b Department of Chemical Engineering Department of Chemical Engineering a a University of Saskatchewan University of Saskatchewan b b The University of Calgary The University of Calgary 4 th International Freiburg Conference on IGCC & XtL Technologies May 3-6, 2010 Dresden, Germany
Transcript of A Review of Fluidized Bed Gasification...
A Review of Fluidized Bed A Review of Fluidized Bed Gasification TechnologyGasification Technology
Todd PugsleyTodd Pugsleyaa and Nader Mahinpeyand Nader Mahinpeybb
Department of Chemical EngineeringDepartment of Chemical EngineeringaaUniversity of SaskatchewanUniversity of Saskatchewan
bbThe University of CalgaryThe University of Calgary
4th International Freiburg Conference on IGCC & XtL TechnologiesMay 3-6, 2010
Dresden, Germany
Outline of PresentationOutline of Presentation
What is fluidization?What is fluidization?•• Basic conceptBasic concept•• GeldartGeldart classification; flow regimesclassification; flow regimes
Applications of fluidizationApplications of fluidizationAdvantage and challenges associated Advantage and challenges associated with fluidizationwith fluidizationFluidized bed gasification technologiesFluidized bed gasification technologiesConcluding remarksConcluding remarks
What is fluidization?What is fluidization?
Air in
Windbox
ECT
Cyclone
TDH
• Fluidizing medium (e.g. air) enters the bed through the windbox and the distributor
•Upward flowing air creates a gas-solid suspension with fluid-like properties
•Entrained solids are separated and returned in the disengagement section (TDH) and cyclone
•Complex multiphase flow measured with techniques such as electrical capacitance tomography (ECT)
What is fluidization?What is fluidization?Video shows vigorous mixing, “splashing” and entrainment
What is fluidization?What is fluidization?
Fluidized bed behavior depends on:Fluidized bed behavior depends on:•• Particle properties (Geldart classification)Particle properties (Geldart classification)•• Fluidizing gas velocity (fluidization regimes)Fluidizing gas velocity (fluidization regimes)•• Vessel geometry including crossVessel geometry including cross--section, section,
diameter, height (scalediameter, height (scale--up)up)
The nature of the twoThe nature of the two--phase flow in a phase flow in a fluidized bed is a complex combination of fluidized bed is a complex combination of these parametersthese parameters
Regimes of fluidizationRegimes of fluidization
Geldart ClassificationGeldart Classification
Advantages of Fluidized BedsAdvantages of Fluidized BedsHigh rates of heat/mass transfer and High rates of heat/mass transfer and efficient gasefficient gas--solid contactingsolid contacting•• Temperature control; effective use of Temperature control; effective use of
catalysts; good mixing; fuel flexibility catalysts; good mixing; fuel flexibility including opportunities for coincluding opportunities for co--feedingfeeding
Continuous addition, removal, Continuous addition, removal, circulation of solids for catalyst circulation of solids for catalyst capture and regeneration; circulation capture and regeneration; circulation of sorbentsof sorbentsImmersion of heat transfer surfaces Immersion of heat transfer surfaces and semiand semi--permeable membranespermeable membranes
Challenges with Fluidized BedsChallenges with Fluidized Beds
The overarching issue is scaleThe overarching issue is scale--upup•• Lab to pilot to demonstration to commercialLab to pilot to demonstration to commercial•• Scale up of existing commercial unitsScale up of existing commercial units
Complex multiphase flowComplex multiphase flowDifferent particles scaleDifferent particles scale--up differentlyup differentlyNo direct control of the fluidized stateNo direct control of the fluidized state•• Defluidization or nonDefluidization or non--optimal fluidized state a optimal fluidized state a
distinct possibilitydistinct possibility
Challenges notwithstanding, there aremany successful applications of fluidizedbed technology.
Applications of FluidizationApplications of Fluidization
1920s 1920s –– Winkler coal gasifierWinkler coal gasifier1940s 1940s –– Fluid Catalytic CrackingFluid Catalytic Cracking1950s 1950s –– Sasol Synthol ProcessSasol Synthol Process1960s 1960s –– SOHIO process SOHIO process (acrylonitrile)(acrylonitrile)1970s 1970s –– Fluid coking (Syncrude)Fluid coking (Syncrude)1980s 1980s –– CFB combustorsCFB combustors1990s 1990s –– Dupont maleic anhydride Dupont maleic anhydride process; methanol to olefins (Exxon)process; methanol to olefins (Exxon)
Fluidized Bed GasificationFluidized Bed GasificationThere are 6 main fluidized bed There are 6 main fluidized bed technologies for coal gasification:technologies for coal gasification:•• KBR Transport GasifierKBR Transport Gasifier•• IDGCC process (Australia)IDGCC process (Australia)•• BHEL processBHEL process•• HighHigh--Temperature Winkler (HTW)Temperature Winkler (HTW)•• KRW or UKRW or U--Gas processGas process•• GreatPoint EnergyGreatPoint Energy
CFBs
BFBs
KBR, U-Gas, GreatPoint are the highest profile technologies
Fluidized Bed GasificationFluidized Bed GasificationKBR Transport Gasifier
T = 1700 F; P = 200 psi
Demonstration plant at Southern Co’s Wilsonville site; commercial units in design for Mississippi Power and in Guandong Province, China
Lower cap and op costs; designed for low-grade coals, including lignite
Fluidized Bed GasificationFluidized Bed GasificationIDGCC – integrates drying of brown coal; CFB process
IDGCC ProcessIDGCC ProcessIDGCC = Integrated Dryer IDGCC = Integrated Dryer Gasification Combined CycleGasification Combined CycleHot syngas is used to dry wet brown Hot syngas is used to dry wet brown (lignite) coal(lignite) coalPurports to achieve lower COPurports to achieve lower CO22emissions, cooling water usage and emissions, cooling water usage and costcost--ofof--electricity per MWhelectricity per MWh550 MW commercial550 MW commercial--scale scale demonstration scheduled for 2013 demonstration scheduled for 2013 startstart--upup
Fluidized Bed GasificationFluidized Bed GasificationKRW or U-Gas process – agglomerating bubbling fluidized bed
UU--Gas ProcessGas ProcessSynthesis Energy Systems purchased Synthesis Energy Systems purchased technology license from GTItechnology license from GTIOperating in Shandong Province, Operating in Shandong Province, producing syngas for a methanol producing syngas for a methanol plant; two other projects under plant; two other projects under development in Chinadevelopment in ChinaKey to operation is removal of ash in Key to operation is removal of ash in the form of agglomerates the form of agglomerates ––““controlled agglomerationcontrolled agglomeration”” –– in a in a singlesingle--stage fluidized bedstage fluidized bed
Fluidized Bed GasificationFluidized Bed GasificationGreatPoint Energy – catalytic gasification direct to methane
GreatPointGreatPoint EnergyEnergyCatalytic gasification process based Catalytic gasification process based on US Patent No. 4,077,778 filed by on US Patent No. 4,077,778 filed by Exxon in 1978Exxon in 1978Low T, high P process goes straight Low T, high P process goes straight to methaneto methaneAlberta Energy Research Institute Alberta Energy Research Institute (AERI) supported pilot testing with (AERI) supported pilot testing with Alberta Alberta feedstocksfeedstocksEconomics unclear given current low Economics unclear given current low NG pricesNG prices
Feedstock ConsiderationsFeedstock Considerations
Fluidized beds the leading technology for Fluidized beds the leading technology for biomass due to aggressive biomass slag biomass due to aggressive biomass slag as well as variability of feed physical and as well as variability of feed physical and chemical characteristicschemical characteristics
Fluidized bed application to coal tends to Fluidized bed application to coal tends to be for lignite and subbe for lignite and sub--bituminous with bituminous with operation below or near the ash operation below or near the ash softening temperature; lowsoftening temperature; low--grade coal grade coal has higher reactivityhas higher reactivity
ConclusionsConclusionsWhat is the future of fluidized bed What is the future of fluidized bed gasification technology?gasification technology?•• Large worldwide reserves of lowLarge worldwide reserves of low--grade, grade,
highlyhighly--reactive coalsreactive coals•• Such coals are good fuels for lowerSuch coals are good fuels for lower--
temperature fluidized bed processestemperature fluidized bed processes•• Announcements of new projects using Announcements of new projects using
fluidized beds show the technology is fluidized beds show the technology is maturingmaturing
•• At this point in time, fluidized bed At this point in time, fluidized bed gasification appears to have a positive gasification appears to have a positive futurefuture
Conclusions (cont.)Conclusions (cont.)What are the challenges?What are the challenges?•• Complex multiphase flow and scaleComplex multiphase flow and scale--up up
challenges continue to present challenges continue to present significant technical and economic risksignificant technical and economic risk
What are the opportunities/R&D What are the opportunities/R&D needs?needs?•• Catalytic gasification to lower capital Catalytic gasification to lower capital
and operating costs of and operating costs of entire entire plant (not plant (not just the gasification island)just the gasification island)
•• Continued development of chemical Continued development of chemical looping gasificationlooping gasification
Carbon Management CanadaA National Centre of Excellence funded by the Canadian government$25 million over 5 years with additional investment from provincesKey focus will be gasification and its application to Western Canada feedstocks (lignite and sub-bit coal and petroleum coke)Emphasis on fluidized bed technology reflects Canadian fluidization expertise
Thank you for your attention
Any Questions?
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