生活垃圾流化床热处置中重金属迁移分布研究

发布时间：2017-12-26 20:22

本文关键词：生活垃圾流化床热处置中重金属迁移分布研究　出处：《燃料化学学报》2016年01期 　论文类型：期刊论文

【摘要】：在流化床实验装置上研究模拟生活垃圾热解、气化、焚烧等热处置过程中重金属Cd、Pb、Zn及Cu的迁移转化,分析氧化还原气氛及温度对重金属挥发特性的影响。结果表明,高温及还原性条件促进了Cd、Pb及Zn的挥发;而氧化性气氛有利于Cu的迁移。热力学平衡模拟结果表明,金属在氧化和还原气氛下的转化途径不同。在还原性气氛下,金属主要以元素态单质或硫化物的形式存在,其熔沸点高低决定了金属挥发程度。反之,CuCl_3等氯化物的生成促进了Cu在氧化性气氛下的挥发。金属基反应在氧化性气氛下得到加强,提高了Cd、Pb及Zn向气相产物转化的起始温度。进一步考察重金属在不同组分的分布及富集规律,大部分以气相形式挥发的重金属易在降温过程中冷凝并富集于飞灰。气流夹带亦是导致重金属迁移的重要原因,流化床的高气速特性对重金属分布有显著影响。
[Abstract]:The migration and transformation of Cd, Pb, Zn and Cu in heavy metals during pyrolysis, gasification and incineration were simulated on a fluidized bed experimental facility. The effects of redox atmosphere and temperature on the volatilization characteristics of heavy metals were analyzed. The results show that high temperature and reductive conditions promote the volatilization of Cd, Pb and Zn, and the oxidizing atmosphere is beneficial to the migration of Cu. The thermodynamic equilibrium simulation results show that the transformation of metal in the atmosphere of oxidation and reduction is different. In the reduction atmosphere, the metal mainly exists in the form of elemental state or sulfide, and its boiling point determines the degree of metal volatilization. On the other hand, the formation of chlorides, such as CuCl_3, promotes the volatilization of Cu in the oxidizing atmosphere. The reaction of metal base is strengthened in the oxidizing atmosphere, which improves the starting temperature of the conversion of Cd, Pb and Zn into the gas phase. The distribution and enrichment rules of heavy metals in different components were further investigated. Most heavy metals volatilized in the form of gas were easily condensed and enriched in fly ash during cooling. The airflow entrainment is also an important cause of heavy metal migration. The high gas velocity characteristics of the fluidized bed have a significant influence on the distribution of heavy metals.
【作者单位】：浙江大学能源清洁利用国家重点实验室;
【基金】：国家重点基础研究发展规划(973计划,2011CB201506)资助项目~~
【分类号】：X799.3
【正文快照】： Received:2015-07-01;Revised:2015-09-03.焚烧法处理固体废弃物具有无害化程度高、减容效果显著及热能回收利用等优点,近年来已成为许多国家处理城市生活垃圾(municipal solid waste,M SW)的主要方式之一。然而,焚烧易造成二次污染,尤其是二恶英等有毒污染物的排放,已成为制

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