Abstract
This paper describes studies concerning the formation of tars in a pressurized fluidized-bed gasifier and their catalytic decomposition in a separate reactor. In the gasification tests, the effects of fuel and freeboard temperature on tar yields and composition were measured. Finnish peat, saw dust and German brown coal were used as fuels. The tar yields decreased with increasing freeboard temperature. The total tar concentration in wood gasification at 900 °C was in the range of 10-18 g/m3n. In peat gasification the concentration at the same conditions was only 3-6 g/m3n and with brown coal less than 1.5 g/m3n. The main components of tar for all the fuels were benzene and naphthalene.
Catalytic decomposition of tar was studied with a bench-scale tube reactor. Sample gas from the pressurized fluidized-bed gasifier was used as feed. Carbonate rocks (dolomites, ankerite), commercial nickel catalyst and inert reference material were used as bed materials. The treatment temperature range studied was 750-900 °C. The most effective material was nickel catalyst, although the dolomites performed nearly as well. At 900 °C, a considerable increase in the thermal value of dry gas was achieved, due to an increase in H2 and CO contents. A long-term test (160 h) was carried out with the nickel catalyst, during which the activity of the catalyst remained almost constant.
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References
Kurkela, E. and Sipilä, K., Power production from biomass and peat by simplified IGCC processes - research activities in Finland. Proc. EPRI 10th Conf. on Coal Gasification Power Plants, San Francisco, 16–18 1991. 19 p.
Kurkela, E., Ståhlberg, P., Laatikainen, J. and Nieminen, M., Removal of particulates and alkali metals from pressurized fluid-bed gasification of peat and biomass - gas cleanup for gas turbine applications. In Proc. Conf. Energy from Biomass and Wastes XV, Washington, D.C., USA, 29–29 March, 1991. Chicago 1991, Institute of Gas Technology.
Kurkela, E. and Ståhlberg, P., Air gasification of peat, wood and brown coal in a pressurized fluidized-bed reactor. 1. Carbon conversion, gas yields and tar formation. Fuel Processing Technology (1992). In press.
Kurkela,E.,Ståhlberg, P., Mojtahedi, W. and Nieminen, M., Pressurised fluidised bed gasification of peat. In Proc. European Symp. on Pyrolysis and Gasification, Luxembourg, May 23–25, 1989.
Leppälahti, J. and Kurkela, E., Behaviour of nitrogen compounds and tars in fluidized bed air gasification of peat. Fuel, 1991, 70, 491–497.
Elliot D.C., Relation of reaction time and temperature to chemical composition of pyrolysis oils. In Pyrolysis Oils from Biomass, ed. Soltes, E. J. and Milne, T. A., ACS Symp.Series 373, Washington D.C., 1988, pp 55–56.
Evans, R. J., Knight, R. A., Onischak, M. and Baby, S. P., Process performance and environmental assessment of the Renugas process. In Proc. Conf. Energy from Biomass and Wastes, ed. Klass, D. L., Institute of Gas Technology, Chicago, 1986.
Simell, P. A. and Bredenberg, J. B., Catalytic purification of tarry fuel gas. Fuel, 1990691219.
Simell, P. A., Lèppälahti, J. K. and Bredenberg, J. B., Catalytic purification of tarry fuel gas with carbonate rocks and ferrous materials. Fuel, 1992, 71, 211.
Bruinsma, O. S. L., Geertsma, R. S., Bank, P. and Moulijn, J. A., Gas phase pyrolysis of coal-related aromatic compounds in coiled tube flow reactor, 1. Benzene and derivatives. Fuel, 1988, 67, 327.
Bruinsma, O. S. L., Tromp, P. J. J., de Sauvage Nolting, H. J. J. and Moulijn, J. A., Gas phase pyrolysis of coal-related aromatic compounds in coiled tube flow reactor, 2. Heterocyclic compounds, their benzo and dibenzo derivatives. Fuel, 1988, 67, 334.
Bruinsma, O. S. L. and Moulijn, J. A., The pyrolytic formation of polycyclic aromatic hydrocarbons from benzene, toluene, ethylbenzene, styrene, phenylacetylene and n-decane in relation to fossil fuels utilization. Fuel Processing Technology, 1988, 18, 213.
Cypres, R., Aromatic hydrocarbons formation during coal pyrolysis. Fuel Processing Technology, 1987, 15, 1.
Crittenden, B. D. and Long, R. The mechanisms of formation of polynuclear aromatic compounds in combustion systems. In Carsinogenesis - a comprehensive survey, ed. Freudenthal, R. and Jones, P.W, Vol 1, Raven Press, New York,1976, pp. 209–223.
Baker, E. G. and Mudge, L. K. Catalysis in biomass gasification. Pacific Northwest Laboratory, Richland, WA, 1984. PNL-5030.
Baker, E. G. and Mudge, L. K., Mechanisms of catalytic biomass gasification. J. Anal. Appl. Pyrolysis, 1984, 6, 285–297.
Baker, E. G., Mudge, L. K. and Wilcox, W. A. In Proc. Fundamentals of Thermochemical Biomass Conversion., Elsevier Appl. Sci. Publ., New York, 1985, 863–874.
Baker, E. G., Mudge, L. K. and Brown, M. D., Steam gasification of biomass with nickel secondary catalysts. J. Ind. Eng. Chem. Res., 1987, 26, 1335–1339.
Alden, H., Espenäs, B - G. and Rensfelt, E., Conversion of tar in pyrolysis gas from wood using a fixed dolomite bed. In Research in Thermochemical Biomass Conversion, ed. Bridgewater, A. V. and Kuester, J.L., Elsevier, New York, 1988, pp. 987–1001.
Corella, J., Herguido, J., Gonzales-Saiz, J.Alday, F. J. & Rodriguez-Trujillo, J.L., Fluidized bed steam gasification of biomass with dolomite and with a commercial FCC catalyst. In Research in Thermochemical Biomass Conversion, ed. Bridgewater, A. V. and Kuester, J. L., Elsevier, New York, 1988, pp. 754–765.
Leppälahti, J., Kurkela, E., Simell, P. and Ståhlberg, P. Formation and decomposition of nitrogen compounds in gasification processes. Submitted for presentation at the Conference on Advances in Thermochemical Biomass Conversion, Interlaken, Switzerland, 1992.
Bernardo, C. A. and Trimm, D. L., The kinetics of carbon deposited on nickel catalysts. Carbon, 1979, 17, 115.
Satterfield, C. N., Heterogeneous catalysis in practice. McGraw-Hill, New York, 1980, pp. 143–145.
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Simell, P., Kurkela, E., Ståhlberg, P. (1993). Formation and Catalytic Decomposition of Tars from Fluidized-Bed Gasification. In: Bridgwater, A.V. (eds) Advances in Thermochemical Biomass Conversion. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-1336-6_20
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DOI: https://doi.org/10.1007/978-94-011-1336-6_20
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