Migration Characteristics Of Heavy Metals During Co-processing Of Solid Waste In Fluidized Bed

The scale of solid waste is huge,and effective disposal and utilization of solid waste will become an issue of increasing concern.I006Ecineration is the preferred method of solid waste disposal,and the characteristics of fluidized bed equipment make it have a greater advantage in solid waste treatment.Due to the different furnace types,there is a big difference in solid waste disposal between fluidized bed boilers and gasifiers.Due to the different furnace types,there are great differences in the solid waste disposal between fluidized bed boiler and gasifier.It is meaningful to understand the migration characteristics of heavy metals in different furnace types.In order to confirm the effect of adding solid waste on the migration characteristics of heavy metals in a fluidized bed the mixing sintering experiments of solid waste and pulverized coal were carried out under different working conditions.The temperature of the tube furnace,the atmosphere in the furnace,and the mixing ratio of solid waste and pulverized coal are controlled.The simulation conditions are all parameters under different furnace-type fluidized bed operating conditions.The simulation experiment of co-combustion of solid waste and pulverized coal shows that Cr,As and Pb are mainly present in the ash in the crucible,accounting for 84.2%to 97.6%,and a small amount of precipitation is in the gas phase.When the temperature rises from 750℃ to 950℃,the content of Cr and Pb in the ash increase by 4.05%and 3.52%,respectively.The law of As is not obvious.The content of other heavy metals in ash except Mo has decreased by 2.8 to 15.7%.The oxides of different trace elements have the characteristics of high melting and boiling points,which make them stable in the crucible.The laboratory test is compared with the field test data.The field test was carried out in a 130t/h fluidized bed boiler and a 10.8MW fluidized bed gasifier coupled with pulverized coal furnace to mix antibiotic slag and household derived waste(RDF).The results show that after co-processing of solid waste,Cr,As and Pb in the fluidized bed boiler mainly exist in fly ash,accounting for 64.2%to 87.6%,and partly in slag,accounting for 11.4%to 3.51%.The introduction of antibiotic slag There is no significant increase in the content of various heavy metals in the discharged material;in the fluidized bed gasifier,94.1%of the volatile heavy metals Hg in the RDF fuel enters the gasification gas with the gasification gas,and the semi-volatile heavy metals Pb and As The proportions are 63.9%and 60.4%.Although some of the heavy metals in the gasifier are stored in the fly ash and slag of the gasifier,most of the heavy metals still enter the boiler,that is,most of the volatile heavy metals in the RDF enter the gasification gas.Thus introduced the boiler burning system.The environmental risk assessment of the mixed-burning solid waste in the field test shows that the harmful heavy metal elements Pb,Hg,Cr,As and Cd of different furnace types are far below the national standard limit,and the cumulative toxicity is less than 1.It is worth noting that the content of most heavy metals in fly ash,slag and gypsum produced after the gasification gas is introduced into the gasifier is significantly increased compared to the blank condition.