Thermal conversion of biomass with emphasis on product distribution, reaction kinetics and sulfur abatement.
Doctoral thesis
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http://hdl.handle.net/11250/233422Utgivelsesdato
2009Metadata
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Sammendrag
Most of the work performed in this study has concentrated on the thermal decomposition of biomass. This was done because to the simple fact that biomass is mainly composed of volatiles that evaporates prior to the gasification stage.
The characteristics of the devolatilized products during pyrolysis are reported in Paper I for several fuels types that have been considered as sources for energy production due to their fast growing abilities. Paper I also reports results for the same biomass types in oxidative atmosphere. An oxidative atmosphere is also important from the gasification point of view because partial combustion is normally used in a gasification process in order to produce the necessary energy for the endothermic gasification reactions. For these studies and the rest of the pyrolysis experiments (papers II and III), the macro-TGA was used which allows the use of large biomass samples (80 g. for most of the experiments).
Another goal of this study was to condition the devolatilized products in order to generate an upgraded gas product with reduced pollutants. Paper II gives a detailed study on the effect of non-thermal plasma on the devolatilized products from pyrolysis of straw pellets, while paper III concentrate on reducing the sulfuric compounds from the gas phase. Two different methods for reducing sulfur emission in pyrolysis of straw were looked upon. The first is an active method that involves hindering the sulfur release with the producer gas through chemical reactions in the char matrix. This was done by introducing calcium based additives to the straw prior to pelletization. The second method was gas product treatment with nonthermal plasma.
Finally the gasification kinetics of two types of wood chars, pine and birch were reported in paper IV. This work was aimed at finding the reaction rates for these types of wood chars.
Består av
Khalil, R. A.; Meszaros, E.; Gronli, M. G.; Varhegyi, G.; Mohai, I.; Marosvolgyi, B.; Hustad, J. E.. Thermal analysis of energy crops Part I. Journal of Analytical and Applied Pyrolysis. (ISSN 0165-2370). 81(1): 52-59, 2008. 10.1016/j.jaap.2007.08.004.Khalil, Roger A.; Seljeskog, Morten; Hustad, Johan E.. Straw pellets pyrolysis. Energy & Fuels. (ISSN 0887-0624). 22(1): 686-692, 2008. 10.1021/ef700532y.
Khalil, Roger A.; Seljeskog, Morten; Hustad, Johan E.. Sulfur abatement in pyrolysis of straw pellets. Energy & Fuels. (ISSN 0887-0624). 22(4): 2789-2795, 2008. 10.1021/ef8001235.
Khalil, Roger; Varhegyi, Gabor; Jaeschke, Susanne; Gronli, Morten G.; Hustad, Johan. CO2 Gasification of Biomass Chars. Energy & Fuels. (ISSN 0887-0624). 23(1): 94-100, 2009. 10.1021/ef800739m.