Thermal cracking and gasification of combustible materials in fluidized bed reactors.

Abstract

At first, the author explains how the bubbling bed model has been conceived, developed and utilized for research and development of fluidized bed reactors. Referring to the Kunii-Kunugi Process for thermal cracking of heavy oils which uses a circulation system of coke particles, it is emphasized that a number of the results of the fundamental investigation have been well utilized throughout the development of the new process. The circulation system of fluidized solids has been applied for industrialization of Pyrox Process, which gasifies the solid waste materials. Judging the successful operation of the preceding two processes, the above circulation system could be well utilized for large scale carbonization-gasification process, which may be suitable to be constructed on an off-shore artificial island for a coal conversion center in the future. For small scale gasification of biomass or the other type of combustible materials, on the other hand, circulation of particles within a vessel is much preferable, one example of which is given in the text. At present, the author maintains that there are sound theoretical background for a rational prediction of gas and/or solids conversion in ordinary fluidized bed reactor.