Study on characteristics of co-gasification reaction and solidification of heavy metals of waste activated carbon and municipal solid waste fly ash
The synergistic treatment of waste activated carbon and municipal solid waste fly ash can reduce energy consumption of melting,meanwhile realize the harmlessly disposal of waste activated carbon.Thermo-gravimetric analysis(TGA)was used to investigate the effect of activated carbon type and particle size on gasification characteristic of waste activated carbon.The co-gasification characteristics of waste activated carbon and municipal solid waste fly ash was also studied via TGA.The feasibility of co-process of waste activated carbon and municipal solid waste fly ash was further verified via a plasma fly ash melting furnace with the treatment capacity of 40 t/d.The results show that the reactivity of waste honeycomb activated carbons are 7-10 times higher than the reactivity of waste granular activated carbon;the mass fraction of ash of granular waste activated carbon is as high as 75%,the reactivity of granular activated carbon is low at high conversion stage,due to the high ash content;the specific surface areas of waste activated carbon with different particle sizes(0.25 mm-0.60 mm,1.00 mm-2.00 mm,3.35 mm-4.75 mm)are 342.9 m2/g,411.3 m2/g,416.5 m2/g,the reaction rate of waste activated carbon with different particle sizes is basically the same.Therefore,the utilization of waste activated carbon with larger particle size during co-processing can reduce the generation of fly ash.The municipal solid waste fly ash has a significant catalytic effect on the reaction of waste activated carbon in the mid-early reaction stage,and the reac-tion rate decreases rapidly in the later reaction stage.The test via plasma fly ash melting furnace shows that the temperature of the combustion chamber increases with the increase of waste activated carbon,the energy consumption is saved,and the molten slag formed by fly ash and waste activated carbon can effectively solidify heavy metals,which verifies the feasibility and economy of the synergis-tic treatment of waste activated carbon and fly ash.
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