Author(s)

S Ogawa, H Sato, Y Bando & M Nakamura

Abstract

Municipal solid waste heated above 820-870 K by using gasifying agent such as air is decomposed thermally to CO, CO2, H2, CH4, gaseous hydrocarbons, tar and char. After thermal destruction of municipal solid waste, fixed carbon in the residual substances (char) composed mainly of carbon and ash reacts with O2, H2O and CO2, and converts to gaseous carbons such as CO and CO2. We have constructed the gasifier which has the municipal solid waste treatment capacity of 20t/d, and successfully demonstrated this new thermal treatment process. It could be confirmed that combustible gases including nearly 10 vol% contents of CO and H2 were generated through the experiment. And the relations of the air injection rate to the temperature in the free board, to the gas composition of product gas, to the product gas low rate and to carbon conversion were verified. The equilibrium calculations of gasification with the minimization method of Gibbs free energy were executed to estimate the product gas composition, Comparing the experimental results with the theoretical calculations, it is concluded that the product gas composition is determined mainly by water gas shift reaction under the conditions of the temperature range of 1020-1170 K and the gas space time of 5 seconds in the free board.

Keywords