Study on pyrolysis and gasification of wood in MSW

摘要

In order to develop municipal solid waste(MSW) pyrolysis/gasification and melting technology with low emission and high efficiency, it was planed that all the main components in MSW and some typical kinds of MSW were pyrolyzed/gasified to propose an expert system for raw MSW. In this paper, wood, which was a prevalent component in MSW, was pyrolyzed and gasified in fluidized-bed reactors at different apparent excess air ratios (EARs), temperatures and fluidizing velocities. For pyrolysis, with temperature increasing from 400 deg C to 700 deg C , the yield of pyrolysis char decreased while that of pyrolysis gas increased (in this paper respectively from 28 percent to 20 percent and from 10 percent to 35 percent ), and when temperature was 500 deg C, the yield of pyrolysis tar reached the highest, up to 38 percent in this paper. It was the optimum for gasification when temperature was 600 deg C and apparent EAR was 0.4. Under the experimental conditions of this paper, gasification efficiency achieved 73 percent, lower heat value(LHV) reached 5800 kJ/(Nm~3) and yield of syngas was 2.01 NrrtVkg. Lower fluidizing velocity was useful to upgrade gasification efficiency and LHV of syngas for wood gasification. Based on the results, the reactive courses and mechanism were analyzed respectively for wood pyrolysis and gasification.