生物质与生活垃圾共气化过程重金属的迁移转化规律

Migration and Transformation of Heavy Metals in the Co-gasification of Biomass and Municipal Waste

为了研究流化床生物质气化协同处置生活垃圾衍生燃料过程中重金属的迁移转化规律,在湖北某循环流化床气化炉耦合燃煤发电厂进行掺烧试验。研究表明重金属主要赋存于飞灰和炉渣中。空白工况下86.2%的Cr赋存于飞灰中,13.3%于炉渣中;75.5%的Pb在飞灰中,23.8%在炉渣中;79.5%的As迁移至飞灰中,11.7%在炉渣中。RDF工况下75.8%的Cr迁移至飞灰,20.7%迁移至炉渣;44.6%的Pb存在于飞灰中,52%存在于炉渣。协同处置后,重金属在飞灰和炉渣中的分配比例明显发生了变化,飞灰中重金属含量减少12.5%~31.3%,炉渣中重金属增加7.33%~20.1%,气化气的引入改变了炉内重金属的分配情况。协同处置可以有效处理生活垃圾,对固废中的热量进行资源化利用,且出炉物料中重金属含量均低于我国现行标准限值。

In order to study the migration and transformation rules of heavy metals in the process of gasification coupling with domestic waste-derived fuel in gasification of circulating fluidized bed coal-fired power plants,a mixed combustion test was conducted in a circulating fluidized bed gasifier in Hubei province.Studies have shown that heavy metals are mainly found in fly ash and slag.Under blank conditions,86.2%of Cr was stored in fly ash,13.3%in slag;75.5%of Pb in fly ash,23.8%in slag;79.5%of As migrates to fly ash,11.7%in slag.Under cooperative conditions,75.8%of Cr migrated to fly ash,20.7%to slag;44.6%of Pb was in fly ash,and 52%was in slag.After co-processing,the distribution ratio of heavy metals in fly ash and slag has obviously changed.The heavy metal content in fly ash had decreased by 12.5%–31.3%,and the heavy metal in slag had increased by 7.33%–20.1%.The introduction of gasification gas changed the distribution of heavy metals in the furnace.Co-processing can effectively dispose of domestic waste,utilize the heat in solid waste for resource utilization,and the content of heavy metals in the discharged materials is lower than the current standard.