Experimental Study And Process Simulation On MSW Pvrolvsis And Gasification In Fixed Bed

The rapid economic development, acceleration of urbanization process and growth of population have brought the problem that the yield of municipal solid waste (MSW) has increased dramatically. There are less and less places available and it is not economic when using landfill which is the main disposal for MSW. Modern MSW incineration can not only reduce but also recover energy from MSW. As a result, the thermal treatment of MSW has been paid more and more attention in China. Compared to incineration, pyrolysis and gasification of MSW is more ad-vanced in emissions aspects. It can realize the nearly zero emission and ash molten while producing clean syngas. The syngas from pyrolysis and gasification of MSW can be used in thermal and electricity produce as MSW incineration, Otherwise, it can also be used in chemical industry and it is much easier to be transported and stored. Thus syngas from gasification is considered to be one of the most promising future energy. It is meaningful both in energy recover and environmental protect to analysis the pyrolysis and gasification characteristics of MSW and improve the technology for wide commercial construction.At first, the background of this research was introduced. Based on the com-parison of several major technologies of MSW disposal and the use for counties and small cities, the fixed bed reactors were chosen for the pyrolysis and gasification of MSW. Second, Aspen Plus was adopted for the simulation of MSW in fixed bed re-actors. The effects of air equivalence ratio, gasification temperature and flue gas on the syngas production were analyzed. The prediction from the simulation results can provide some process fundamentals and found the basis for pilot scale and commer-cial scale operations.In order to investigate the pyrolysis and gasification characteristics, especially the syngas and tar production of MSW in fixed bed reactors, bamboo, paper and PE were used as the typical MSW components. The mechanisms under different heating rates were researched. And the effects of CaO catalyst on the pyrolysis and gasifica- tion characteristics of the three different components were also studied due to its re-forming function on the syngas and tar. First, TG-FTIR was used for studying the weight lost process and gas from MSW components pyrolysis at slow heating rates from10k/min to40k/min and different adding amounts of CaO catalyst. Second, Py-GC-MS was adopted for analyzing the production of different components in the gaseous organics at high heating rates from800k/min to lOk/ms. Especially the qualitative and quantitative investigate of the effect of CaO on the concentration of different components in the tar.On the basis of the study of pyrolysis and gasification mechanisms of MSW using TG-FTIR and Py-GC-MS, experiments of pyrolysis and gasification of MSW were carried out in a quartz tube made fixed bed and a self designed pilot scale5kg/h fixed bed reactor. First, in the quartz tube made fixed bed, the effect of mois-ture concentration and amounts of CaO additives on the syngas production, tar pro-duction and other gasification characteristics of the three main MSW components were studied. Otherwise, the GC-MS was used to analysis the concentration of dif-ferent organic components in the tar from different experimental conditions. And the effects of different experimental conditions on the compositions of tar were obtained. Second, in the self designed continuous feeding fixed bed reactor, the pyrolysis and gasification of MSW in steam and air were studied. The characteristics of syngas production from pyrolysis and gasification of the two main MSW components at different gasification temperature, air equivalence ratio and steam/fuel ratio were studied. Additionally, the effects of CaO additive on the syngas production and the lower heating value (LHV) were analyzed.