Abstract—We attempted to reduce and reform tar-derived pyrolysis during coal gasification. Volatile–char contact can be used to reduce tar emissions. We developed a novel circulating fluidized bed consisting of a bubbling bed pyrolyzer and combustor made of quartz for direct observation of the solids’ behavior. Raw coal was fed to the pyrolyzer (700–900°C) and gases, tar, and char were formed. The resultant char was circulated with bed material to the combustor, and combusted completely or partially. During partial combustion, some chars were combusted, and the uncombusted chars were circulated back to the pyrolyzer (termed char recycling). During char recycling, the recycled char could contact tar derived from pyrolysis, and the volatile–char interaction was enhanced with char recycling time. The product gas yield, mainly H2 and CO, increased, whereas the heavy and light tar yields decreased with char recycling.
Index Terms—Circulating fluidized bed, coal pyrolysis, tar reduction, tar reforming, volatile–char interaction.
Y. Kawabata, T. Wajima, and H. Nakagome are with the Department of Urban Environment Systems, Graduate School of Engineering, Chiba University, Chiba, Japan (e-mail: z8t0266@students.chiba-u.jp, wajima@tu.chiba-u.ac.jp, nakagome@tu.chiba-u.ac.jp).
S. Hosokai, Y. Suzuki, and K. Matsuoka are with the Clean Gas Group, Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan (e-mail: koichi-matsuoka@aist.go.jp).
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Cite: Y. Kawabata, T. Wajima, H. Nakagome, S. Hosokai, Y. Suzuki, and K. Matsuoka, "Reduction and Reforming of Tar with Enhanced Volatile-Char Interaction during Coal Pyrolysis," International Journal of Chemical Engineering and Applications vol. 6, no. 4, pp. 281-284, 2015.
