电力科技与环保2025，Vol.41Issue(5)：769-779,11.DOI:10.19944/j.eptep.1674-8069.2025.05.008
煤燃烧过程中砷、硒、铬迁移转化研究
Study on the migration and transformation of arsenic,selenium,and chromium during coal combustion
摘要
Abstract
[Objective]The toxic trace elements emitted from coal combustion have posed huge threats to the environment and human health.Clarifying the migration and transformation characteristics of trace elements during coal combustion is of great significance for their effective removal and clean emissions of coal-fired flue gas.[Methods]This work takes a coal sample from a 660 MW coal-fired power plant as the object,and uses tube furnace combustion experiments and chemical thermodynamic simulation to investigate the effects of temperature and atmosphere on the migration and transformation of toxic trace elements arsenic(As),selenium(Se),and chromium(Cr)during the coal combustion process.[Results]Under different combustion conditions,As and Se are primarily distributed in fly ash,while Cr is predominantly in bottom ash.An increase in temperature under an air atmosphere facilitates the migration of As from bottom ash to fly ash,while an oxygen-enriched atmosphere promotes the migration of As into the flue gas.At 700℃or 900℃,an increase in O2 concentration in an oxygen-enriched atmosphere promotes the conversion of As in bottom ash to As in fly ash.The As present in coal ash is primarily in the form of AlAsO4(s)and Ca3(AsO4)2(s).In an air atmosphere,as the temperature rises,Se undergoes migration from fly ash to bottom ash,and from bottom ash and flue gas to fly ash.At 700℃or 900℃,an increase in O2 concentration in an oxygen-enriched atmosphere enhances the distribution of Se in fly ash.The Se present in fly ash and flue gas is primarily in the forms of CaSeO4(s)and SeO2(g),respectively.An increase in temperature under an air atmosphere promotes the migration of Cr from bottom ash to fly ash.The distribution of Cr among the distributions in a 60%O2/40%CO2 atmosphere is similar to that in a 21%O2/79%CO2 atmosphere,with a higher proportion distributed in the flue gas.The Cr present in bottom ash and fly ash is primarily in the forms of Cr2(SO4)3,CaCr2O4,CrO2,and Cr2O3.[Conclusion]During the coal combustion process,As and Se have high volatility and are mostly distributed in fly ash,while Cr has low volatility with mostly distributed in bottom ash.Temperature and O2 concentration have important effects on the migration and transformation of As,Se,and Cr.Special attention should be paid to the removal of As and Se from fly ash and flue gas,as well as the environment leaching of Cr from bottom ash.关键词
煤燃烧/砷/硒/铬/迁移转化/实验研究/化学热力学Key words
coal combustion/arsenic/selenium/chromium/migration and transformation/experimental study/chemical thermodynamics分类
能源科技引用本文复制引用
梁鑫,马敬轩,赵士林..煤燃烧过程中砷、硒、铬迁移转化研究[J].电力科技与环保,2025,41(5):769-779,11.基金项目
湖南省科技创新计划项目(2023RC3043) （2023RC3043）
