燃煤烟气脱砷实验研究

发布时间：2018-03-14 20:46

  本文选题：燃煤烟气　切入点：脱砷　出处：《华北电力大学》2017年硕士论文　论文类型：学位论文

【摘要】：我国的大气污染属于典型的煤烟型污染,煤炭燃烧过程产生的SO_2、NOx、颗粒物、痕量重金属、VOCs等污染物,对生态环境和人类健康造成了严重危害。砷是煤中最易挥发的有害微量元素之一,被国际癌症研究机构列为第一类致癌物,应格外引起人们的关注。目前对于燃煤电厂砷污染控制的研究相对较少,因此开发一种投资费用少、运行成本低、绿色环保的烟气脱砷工艺对燃煤电厂砷的减排以及最终实现多种污染物联合脱除有着极为重要的意义。本文在阅读大量文献的基础上设计了脱砷实验方案,搭建脱砷室验台。通过筛选多种氧化剂,最终选取了H_2O_2为基础氧化剂,Na_2S_2O_8为添加剂制作复合氧化剂。采用自行设计的脱砷实验台考察了复合氧化剂的浓度配比和反应条件等因素对脱砷效率的影响,确定了H_2O_2/Na_2S_2O_8复合氧化剂的最佳反应条件:Na_2S_2O_8与H_2O_2的最佳摩尔浓度比为0.01/1(mol/mol),反应温度为50℃,复合氧化剂p H值为5.5,烟气流量为1.0L/min、入口处砷浓度为0.421mg/m~3。在最佳反应条件下获得的平均脱砷效率96.3%。为了模拟燃煤电厂烟气的实际工况,分别考察了O_2、CO_2、SO_2、NO浓度对脱砷效率的影响,实验结果表明:随着O_2和CO_2浓度的增加,脱砷效率几乎不受影响;随着SO_2浓度增大,脱砷效率呈下降趋势;随着NO浓度增大,脱砷效率先下降后缓慢上升。通过对脱砷产物进行AFS、液相色谱和XRD检测,证实了脱砷产物为Ca_3(As O_4)_2。根据产物表征结果和相关文献,推测了H_2O_2/Na_2S_2O_8复合氧化剂的脱砷机理。
[Abstract]:The air pollution in our country belongs to the typical coal smoke pollution, so _ 2no _ x, particulates, trace heavy metals such as VOCs produced by the coal combustion process, etc. Arsenic is one of the most volatile harmful trace elements in coal. There is relatively little research on arsenic pollution control in coal-fired power plants, so the development of a kind of arsenic pollution has low investment cost and low operating cost. The process of removing arsenic from flue gas by green environment is of great significance to the reduction of arsenic in coal-fired power plants and the realization of combined removal of various pollutants. Based on the reading of a large number of literatures, the experimental scheme of arsenic removal is designed in this paper. Setting up a laboratory test bench for arsenic removal. By screening various oxidants, Finally, H _ 2O _ 2 was selected as the basic oxidant to make composite oxidant. The influence of the concentration ratio and reaction conditions of the compound oxidant on the efficiency of arsenic removal was investigated by using the self-designed experimental bench. The optimum reaction conditions for the composite oxidant, the one of the H2O2S _ 2O _ 8, were determined: the optimum molar concentration ratio of the two was 0.01 / 1 mol / mol / h, and the reaction temperature was 50 鈩，

本文编号：1612822