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Thermochemical Processing

Research Capabilities and Interests Relevant to
Production of Liquid Fuels from Biomass

The Thermochemical Processing Group at Georgia Tech conducts research in pyrolysis, gasification and combustion of biomass, biomass wastes, and other carbonaceous fuels.  The research focuses on production of biorenewable fuels, chemical, and power, and recovery of inorganic chemicals from wastes. The IPST Center has extensive experimental capabilities, and capabilities in thermodynamics analysis, process design, simulation and economics. The group’s expertise has been utilized extensively by industrial practitioners of pyrolysis, gasification and combustion .


  • Cost-Benefit Assessment of Gasification-Based Biorefining at U.S. Kraft Pulp Mills (in collaboration with Princeton University)
  • Process Design and Economic Analysis for Integrated Biorefineries
  • Kinetics of Carbon Conversion in Gasification of Biomass Fuels
  • Sulfur Speciation during Gasification of Sulfur-containing Biomass Fuels
  • Direct Causticizing with Titanates and Borates During Pressurized Black Liquor Gasification of Black Liquor
  • Catalyst Development for Destruction of Tar from Gasification of Sulfur-containing Biomass Fuels
  • Performance Assessment and Process Enhancement of the Biomass Waste Gasifier at the Weyerhaeuser/New Bern site
  • Evaluation of Tar Formation, Control and Destruction for the Biomass Waste Steam Reformer at the Georgia-Pacific/Big Island Site


Characterization of Thermochemical Processes for Production of Liquid Fuels from Biomass

The Group’s interest and capabilities are in the thermochemical conversion of biomass and biomass waste for the production of liquid fuels, including

  • the rate of evolution of light gases, organic vapors, and tar species during pyrolysis and gasification of biomass and other fuels
  • the rate of evolution and reformation of tar species
  • gasification kinetics of fixed carbon
  • the rate of evolution and transformation of sulfur-containing gases, nitrogen species, and alkali metal vapor during pyrolysis and gasification of biomass wastes

Cleanup and Conditioning of Synthesis Gas from Biomass

  • The Group’s interests and capabilities are in these areas:
  • catalytic tar destruction
  • in-situ capture of sulfur gases by alkali and alkaline earth metal salts
  • in-situ transformation of nitrogen species to NO and N2
  • vaporization and transformation of metals

Process Design and Economics of Liquid Fuels from Biomass

Several members of the group have capabilities and interests in this area. Dr. Matthew Realff’s interests and capabilities are in the systems and process engineering aspects of the use of wood as a feedstock for energy production.  He is interested in the logistics of biomass procurement and the interaction of the scale of the process with the costs of raw material and product.  Drs. Jim Frederick and Kristiina Iisa have interests and capabilities in process engineering and economic analysis of thermochemical processing of biomass and gas cleanup for production of liquid fuel. Drs. Realff and Frederick are interested in the design of sustainable processes for the manufacture of fuels from renewable resources.

Experimental Facilities

Pressurized Entrained-Flow Reactor: This facility is designed to conduct high temperature (to 1500° C) chemical reactions at high pressure (to 80 bar) in a controlled gas atmosphere, at residence times to about 10 seconds.  It has proven to be especially useful for pyrolysis, gasification, and combustion studies.  In typical experiments, dry solid particles in the size range of approximately 100 µ are fed into the reactor and flow downward, co-current with a gas stream, through the heated zone of the reactor.  The particles and gas are collected in a water-cooled collector.  The particles move through the reactor in very nearly plug flow, and their residence time is controlled by the position of a water-cooled collector (path length of the heated zone) and the gas velocity in the reactor.  The particles are heated rapidly in the reactor, reaching the reactor temperature in about 0.1 seconds. Carbon conversion, product gas composition, tar production, sulfur species distribution in the gas and solid phases, volatilization of alkali metals, and the fate of fuel nitrogen and distribution of nitrogen species can be measured by analyzing the solid products collected and the gas is exiting the reactor.

Atmospheric-Pressure Laminar Entrained-Flow Reactor: This facility is very similar in design to the pressurized entrained flow reactor, but is smaller, operates at atmospheric pressure and temperatures up to 1150° C, and at shorter residence times (to about two seconds).

Instrumentation and Analytical Facilities: These reactors are equipped with on-line gas analysis equipment that includes a molecular-beam mass spectrometer with gas chromatography capability, Fourier-Transform Infrared spectrometers, and an NO/NOX analyzer. An on-line tar analyzer is being purchased.

The Thermochemical Processing Laboratory has advanced capabilities for measuring the composition of solid residues. These include a Capillary Electrophoresis Analyzer for cation and anion species and a head-space gas chromatograph for carbonate and volatile species. GT’s IPST Center has a world-class Analytical Laboratory and professional staff that supports the research on thermochemical processing of biomass. Its capabilities include detailed analysis of carbohydrates including cellulose, hemicelluloses, reducing sugars, lignin, fatty acids, and other organic constituents. The laboratory is equipped with a GC-mass spectrometer, a gel permeation chromatograph, a high performance liquid chromatograph, an FTIR spectrometer, an NIR spectrometer a high performance anion exchange chromatograph with pulsed amperometric detector, an ICP emission spectrometer, and other analytical equipment (see http://ipst.gatech.edu/testing_services/chemical_analysis/index.html).

Tar Characterization and Destruction Facilities. Tar produced during pyrolysis or gasification can be collected from either of the entrained-flow reactors as well as from a fixed bed reactor used for biomass gasification. The laboratory is also equipped with a bench-scale gasifier and tar destruction reactor that are used to evaluate and develop new sulfur-tolerant catalysts for converting tar species produced during gasification of biomass or other fuels to CO and hydrogen. One sulfur-tolerant catalyst that has been developed is being patented and will be licensed commercially.

Experimental facility for biomass tar production and destruction.

Process Design and Economics Laboratories: The School of Chemical & Biomolecular Engineering is the home of GT’s Center for Process Systems Engineering. The CPE undertakes the design, simulation, and economic evaluation of chemical process systems including those for producing liquid fuels from biomass. Process simulation software available through the CPE includes Aspen HYSYS® and other simulation software. A spreadsheet-based process simulator, BioRefinOpt™, developed recently by Dr. Jim Frederick and Steve Lien, is also available.


William James Frederick, Jr.
Professor of Chemical & Biomolecular Engineering
Phone: 404-894-2082
E-mail: jim.frederick@chbe.gatech.edu
Dr Frederick’s research is focused on experimental studies of combustion and gasification of biomass wastes, alkali metal and sulfur chemical processes at high temperatures, fouling of boilers, process modeling of combustion and gasification, and integration of biomass conversion processes into wood- and agricultural waste-based biorefineries.

Maarit Kristiina Iisa
Principal Research Engineer                                            
School of Chemical & Biomolecular Engineering              
Phone: 404-894-5757
E-mail: kristiina.iisa@ipst.gatech.edu
Dr. Iisa’s expertise includes experimental studies of combustion and gasification of pressurized coal and biomass wastes, sulfur gas removal, alkali metal, heavy metals, and NO­X chemistry, and thermodynamics and process simulation of combustion and gasification processes.

Scott A. Sinquefield                                                     
Senior Research Engineer                                               
Phone: 404-385-0241                                                    
E-mail: scott.sinquefield@ipst.gatech.edu
Dr. Sinquefield’s expertise includes experimental studies of combustion and gasification of biomass wastes, alkali metal chemistry and fouling of boilers, and in-situ caustic production from alkali metal-containing waste streams. During his Ph.D. research, he spent three years with Dr. Larry Baxter at the Combustion Research Facility of Sandia National Laboratories in Livermore, CA, where he investigated inorganic aerosol formation and deposition.

Matthew J. Realff                                                        
Associate Professor
Chemical & Biomolecular Engineering
Phone: 404-894-1834                                                    
E-mail: matthew.realff@chbe.gatech.edu

Dr. Matthew J Realff has interests in the systems and process engineering aspects of the use of wood as a feedstock for energy production.  He is interested in the logistics of biomass procurement and the interaction of the scale of the process with the costs of raw material and product.  He is engaged in research into the rapid assessment of different technical routes from wood to ethanol and the management of the uncertainty in decision-making in production processes.

Nikolai DeMartini                                                       
Research Engineer                                                          
Phone: 404-385-7054                                                    
E-mail: nikolai.demartini@ipst.gatech.edu
Dr. DeMartini's Ph.D. recently completed his Ph.D. thesis with the Combustion Chemistry Group at Abo Akademi University, Turku, Finland. His research focused on understanding the chemistry of nitrogen and sulfur compounds in closed chemical cycles, with an emphasis on minimizing emissions from combustion devices.

Michael Buchanan
Manager, Chemical Analysis Group
Phone: 404-894-5338                                                    
E-mail: mike.buchanan@ipst.gatech.edu
Mike Buchanan has more than 25 years experience in analytical chemistry, methods development, and analytical laboratory management. He has expertise in mass spectrometry, infrared spectroscopy, chromatography, electrophoresis and other instrumental and classical analytical techniques, and extensive experience in analysis of biomass and its products of combustion and gasification.


Alan Ball
B.A. Chemistry
Taishan Fan (post-doc)
Ph.D, Surface Chemistry
Steven J. Lien
B,S. Chemical Engineering; M.S. paper Science & Engineering
Xiaoyan Zeng
M.S. Chemical Engineering, M.S. Computer Science

Christopher Young
Ph.D. Candidate
Thesis topic: High Temperature Gasification of Biomass Waste in a Flow Reactor at Elevated Pressure
Farminder Anand
Ph.D. Candidate
Thesis topic: Process Systems Considerations in Forest Biorefineries with Thermochemical Processing of Wood Wastes
Vipul Kumar
M.S. Candidate
Thesis topic: Energy and Materials from Sludge from Biomass Processing
Courtney Malbrue
M.S. Candidate
Thesis topic: Control of Heavy Metal Emissions from Waste Fuel Boilers


Biorefinery Design and Economics
Larson,E.D., Consonni, S. Katofsky, R.E., Iisa, K., Frederick, W.J., Cost-Benefit Assessment of Gasification-Based Biorefining at U.S. Kraft Pulp Mills , report to USDOE under contract DE-FC26-04NT42260, July 2006.
Ozyurt, D.B., M.J. Realff, Combining a Geographical Information System and Process Engineering to Design an Agricultural-Industrial Ecosystem, Journal of Industrial Ecology, Volume 5, #3, p13-31 2001.
Realff, M.J. Industrial Symbiosis: Refining the Biorefinery, Journal Industrial Ecology Special Issue on Biorefineries.
Larson, E.; McDonald, G.; Yang, W.; Frederick, W.; Iisa, K.; Kreutz, T.; Malcolm, E.; Brown, C. Cost-Benefit Assessment of Black-Liquor Gasifier/Combined-Cycle Technology Integrated into a Kraft Pulp Mill, Tappi J. 83(6):57 (2000).

Pyrolysis, Gasification and Syngas Production
Young, C., Frederick, W.J., Iisa, K., Pressure Effects on Black Liquor Gasification, Paper no. 545c, AIChE Annual meeting, Cincinnati, November, 2005.
Sricharoenchaikul, Viboon; Frederick, Wm. James; Agrawal, Pradeep. Carbon distribution in char residue from gasification of kraft black liquor. Biomass and Bioenergy (2003), 25(2), 209-220.
Nohlgren, I.; Sricharoenchaikul, V.; Sinquefield, S.; Frederick, W. J., Jr.; Theliander, H.  Black liquor gasification with direct causticization using titanates in a pressurized entrained-flow reactor. Part I: Kinetics of the causticization reaction. Journal of Pulp and Paper Science (2003),  29(4), 107-113.
Sricharoenchaikul, V; Agrawal, P.; Frederick, W.J. Jr. Black Liquor Gasification Characteristics. 1. Formation and Conversion of Carbon-Containing Product Gases during Gasification of Black Liquor. Industrial & Engineering Chemistry Research, (2002), 41(23), 5640 - 5649.
Sricharoenchaikul, V; Agrawal, P.; Frederick, W.J. Jr. Black Liquor Gasification Characteristics. 2. Measurement of Condensable Organic Matter (Tar) At Rapid Heating Conditions. Industrial & Engineering Chemistry Research (2002), 41(23): 5650 – 5658.
Sricharoenchaikul, V.; Hicks, A.L.; Frederick, W J. Jr.  Carbon and char residue yields from rapid pyrolysis of kraft black liquor. Bioresour. Technol.  (2001), 77(2), 131-138.
Yrjas, P., Hupa, M., Iisa, K., “Pressurized Stabilization of Desulfurization Residues from Gasification Processes”, Energy & Fuels, 10 (1996), 1189-1195.
Yrjas, P., Iisa, K., Hupa, “Limestone and Dolomite as Sulfur Absorbents under Pressurized Gasification Conditions," Fuel, 75 (1996), 89-95.
Dayton, D.C., Frederick, W.J., 1996, Direct Observation of Alkali Vapor Release During Biomass Combustion and Gasification. 2. Black Liquor Combustion at 1100°C. Energy&Fuels, 10(2):284-292 (1996).

Combustion Processes
Frederick, Wm. James; Ling, Alisa; Tran, Honghi N.; Lien, Steven J.  Mechanisms of sintering of alkali metal salt aerosol deposits in recovery boilers.  Fuel  (2004),  83(11-12),  1659-1664.
Frederick, W. J., Jr.; Vakkilainen, E. K.; Tran, H. N.; Lien, S. J.  The Conditions for Boiler Bank Plugging by Submicrometer Sodium Salt (Fume) Particles in Kraft Recovery Boilers.    Energy & Fuels (2004), 18(3), 795-803.
Frederick, Wm. James, Jr.; Vakkilainen, Esa K.  Sintering and Structure Development in Alkali Metal Salt Deposits Formed in Kraft Recovery Boilers. Energy & Fuels (2003), 17(6),  1501-1509.
Gea, G.; Murillo, M. B.; Arauzo, J.; Frederick, W.J. Jr. Swelling Behavior of Black Liquor from Soda Pulping of Wheat Straw. Energy & Fuels, (2003) 17(1), 46 – 53.
Iisa, K., Lu, Y., Salmenoja, K., “Sulfation of Potassium Chloride at Combustion Conditions,” Energy & Fuels 13 (1999), 1184-1190.
Boonsongsup, L., K. Iisa, and W.J. Frederick, Kinetics of Sulfation of NaCl at Combustion Conditions. Industrial and Engineering Chemistry, 36(10):4212-4216 (1997).
Stenberg, J., Frederick, W. J., Boström, S., Hernberg, R., Hupa, M., 1996, Pyrometric temperature measurement method and apparatus for measuring particle temperatures in hot furnaces, Review of Scientific Instruments, 67(5):1976-1984 (1996).

Control of Emissions from Thermochemical Processing
Tran, Khanh-Quang; Iisa, Kristiina; Steenari, Britt-Marie; Lindqvist, Oliver.  A kinetic study of gaseous alkali capture by kaolin in the fixed bed reactor equipped with an alkali detector. Fuel  (2005),  84(2-3), 169-175. 
Tran, Quang K.; Steenari, Britt-Marie; Iisa, Kristiina; Lindqvist, Oliver.  Capture of Potassium and Cadmium by Kaolin in Oxidizing and Reducing Atmospheres.  Energy & Fuels 18 (2004) 1870-1876.
Tran, Khanh-Quang; Iisa, Kristiina; Hagstrom, Magnus; Steenari, Britt-Marie; Lindqvist, Oliver; Pettersson, Jan B. C.  On the application of surface ionization detector for the study of alkali capture by kaolin in a fixed bed reactor.  Fuel (2004), 83(7-8),  807-812.
Wu, S. L., Iisa, K., “Kinetics of NO Reduction by Black Liquor Char,” Energy & Fuels, 12 (1998), 457-463.
Yrjas, P., Iisa, K., Hupa, M., "Comparison of SO2 Capture Capacities of Limestones and Dolomites under Pressure," Fuel, 74 (1995), 395-400.
Iisa, K. and Hupa, M., "Rate Limiting Processes for the Desulphurisation Reaction at Elevated Pressures", Journal of The Institute of Energy, 65 (1992), 201-205.
Iisa, K., Hupa, M, and Yrjas, P., "Product Layer Diffusion in the Sulphation of Calcium Carbonate", Twenty-Fourth Symposium (International) on Combustion, The Combustion Institute 1992, 1349-1356.

Technical Reports
Grace, T.M., Frederick, W.J., Salcudean, M., Wessel, R.A., Black Liquor Combustion Validated Recovery Boiler Modeling Final Report, U.S. DOE Report, August 1998.
Frederick, W.J., Iisa, K., Wåg, K.J., Reis, V.V., Boonsongsup, L., Forssén, M., Hupa, M., Sodium and Sulfur Release and Recapture During Black Liquor Burning, U.S. DOE Report DOE/CE/40936-T2 (DE96006558), August 1995.



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