Pyrolysis-combustion of rural solid waste: Self-sustaining operation and pollutants emission

Abstract

Rural solid waste (RSW) is a serious problem which not only causes environmental pollution, but also limits the development of rural areas. Pyrolysis is an alternative since it can efficiently reduce RSW, meanwhile, the treatment capacity is matched for RSW production. However, conventional pyrolysis of RSW faces two important issues: energy cost and pollutant emission. Therefore, in this work, food waste (FW) was taken as the representative of high-moisture and low-heating-value organic waste in RSW, the energy required for pyrolysis, and the heat produced by combusting pyrolytic products were investigated. Based on calculating the Energy Ratio of Production to Consumption (ERPC) index, the self-sustaining pyrolysis-combustion conditions were established, and the carbon footprints in various scenarios were discussed. Additionally, waste paper, plastic, fabric and poplar scraps were selected as the representative organic wastes (OW) in RSW. The pyrolytic behaviors and pollutant emission (NOx and SO2) of individuals and blended OW were investigated. Compared to direct combustion of OW, the NOx and SO2 emissions can be reduced by 86 % and 100 %, respectively, during pyrolysis-combustion process. Combined the above aspects, it is proved pyrolysis-combustion can be a feasible approach to treat RSW, due to it can be operated without extra energy supply, and also shows obvious environmental benefits compared to direct combustion technology.