Volatilization Characteristics of Lead and Cadmium During Co-Processing of Hazardous Waste in Boilers
XIAO Haiping;CHEN Yu;YAN Dahai;LI Li;WANG Ning;PENG Zheng;WANG Qi;School of Energy,Power and Mechanical Engineering,North China Electric Power University;Research Institute of Solid Waste Management,Chinese Research Academy of Environmental Sciences;Foreign Economic Cooperation Office,Ministry of Environmental Protection;
The volatilization characteristics of cadmium( Cd) and lead( Pb) in different chemical forms during the co-processing of hazardous waste in boilers were studied. The volatilization proportions( α),residue proportions( r) and apparent activation energies( E)of Pb and Cd in different chemical forms were determined by experiments of co-incineration and residue digestion. The results showed that the volatilization proportions of Pb and Cd in the forms of sulfide,chloride,sulfate and oxide increased with the increases of temperature( T) and residence time( t). The volatilization proportions of Pb and Cd in different chemical forms varied below 950 ℃. For example,the final volatilization proportion of PbCl_2 was close to 64%,but that of Pb O was only 17% at 800 ℃. When the temperature was over1250 ℃,the final volatilization proportions of Pb and Cd in each chemical form was over 95%. The residue proportions of Pb and Cd in each chemical form were below 0. 3% at 1400 ℃. The volatilization laws of Pb and Cd during co-processing in boilers were modeled by chemical reaction kinetics. The apparent activation energy of Pb in Pb S,PbCl_2,PbSO_4 and PbO were23. 64,18. 44,65. 79 and 61. 35 k J/mol,respectively,while those of Cd in CdS,CdCl_2,CdSO_4 and CdO were 53. 22,20. 87,42. 42 and 28. 75 k J/mol,respectively. Kinetic equations α =f( T,t) on the volatilization of Pb and Cd in different chemical forms were achieved based on the apparent activation energies.The equations can be used to predict the volatilization proportions of Pb and Cd during co-processing in boilers and determine hazardous waste categories suitable to be co-processed in boilers.
【Fund】： 国家环境保护公益性行业科研专项(201209023);; 中央高校基本科研业务费专项资金项目(2014MS19);; 中挪合作项目(CHN 2150 09/059)
【CateGory Index】： X327
【CateGory Index】： X327