Abstract:

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.

Key words: gasifier, refuse derived fuel, heavy metals, migration law