我国生活垃圾焚烧发电过程中温室气体排放及影响因素 ——以上海某城市生活垃圾焚烧发电厂为例

以上海某城市生活垃圾焚烧发电厂为例,采用上游-操作-下游(UOD)表格法,分析了生活垃圾焚烧发电过程中不同环节的温室气体排放贡献,及影响其排放的主要因素.结果表明,目前我国生活垃圾焚烧发电过程是温室气体排放源,以吨垃圾净CO2排放量计,达166~212kg.生活垃圾中自含化石碳对温室气体排放的贡献最大,CO2排放量为257kg/t;因焚烧发电上网而获得的净减排量为120kg/t;垃圾收运、辅助物料消耗及焚烧灰渣处理等引起的排放量总计为27~45kg/t.生活垃圾沥出渗滤液后续处理过程的温室气体排放量为7.7kg/t.节省焚烧过程辅助物料使用和改变焚烧灰渣处置方式能够减少温室气体排放量,但是减排效果有限.我国各地区电能基准线排放因子存在差异,对焚烧过程温室气体排放的影响为0~13%.降低生活垃圾含水率、提高垃圾可发电量是我国生活垃圾焚烧发电过程温室气体排放源汇转换的关键途径.

GHG emissions from Chinese MSW incineration and their influencing factors-Case study of one MSW incineration plant in Shanghai

Upstream-operation-downstream (UOD) method was applied to study the greenhouse gas (GHG) emissions from one municipal solid waste (MSW) incineration plant in Shanghai. The contribution of each step and the influencing factors to GHG emissions were analyzed. The results showed that the incineration plant was source of GHG, which contributed 166~212kg CO2-eq/t of waste for incineration (fww). The fossil carbon content in the waste was found to be the critical factor, emitting 257kg CO2-eq/t fww. The utilization of electricity generated from incineration could save 120kg CO2-eq/t fww. Other parts (e.g. collection and transportation of wastes, disposal of bottom ash and fly ash and consumption of auxiliary material) released 27~45kg CO2-eq/t fww. GHG emissions from leachate treatment were 7.7kg CO2-eq/t fww. By saving of the auxiliary materials and changing of the disposal patterns of ashes, the GHG emissions can be mitigated in a limited degree. GHG savings varied by 0~13% when electricity factors in different regions were considered. In order to realize source-sink conversion of GHG for MSW incineration, the key approach was to increase the electricity generation capacity of the MSW by reducing water content.