烧结半干法脱硫灰中亚硫酸钙氧化特性  

Oxidation characteristics of calcium sulfite in sintering desulphurized ash

作　　者：钱大益 王艳 邢奕 金明辉 苏伟 张梦然 郑跃博 刘媛梦 段淑雅 QIAN Dayi;WANG Yan;XING Yi;JIN Minghui;SU Wei;ZHANG Mengran;ZHENG Yuebo;LIU Yuanmeng;DUAN Shuya(School of Energy Environmental Engineering,University of Science and Technology Beijing,Beijing 100083,China;Key Laboratory of Pollutant Chemistry and Environmental Treatment,School of Chemistry and Environmental Science,Yili Normal University,Yining 835000,China)

机构地区：[1]北京科技大学能源与环境工程学院,北京100083 [2]伊犁师范大学化学与环境科学学院污染物化学与环境治理重点实验室,伊宁835000

出　　处：《工程科学学报》2023年第11期1985-1996,共12页Chinese Journal of Engineering

基　　金：新疆维吾尔自治区自然科学基金资助项目(2022D01C333)。

摘　　要：针对烧结半干法脱硫灰中CaSO_(3)在不同反应条件下干热氧化的变化规律,研究了温度、气体中O_(2)含量与流速、钙类化合物、铁氧化物(Fe_(2)O_(3))、水蒸汽含量与流速等对CaSO_(3)氧化的影响.结果表明:反应遵循阿累尼乌斯方程,在空气氛围,升温速度为10℃·min^(–1)的条件下,450℃、75 mL·min^(–1)的气体流速为经济性干热氧化的最佳工艺条件,水汽对CaSO_(3)氧化反应具有两面性;钙的氧化物对CaSO_(3)氧化反应通过抑制O_(2)-、SO_(3)-自由基的生成而抑制反应进行,3种钙类氧化物对CaSO_(3)氧化抑制作用从弱到强为:CaCO_(3)<Ca(OH)_(2)<CaCl_(2);Fe_(2)O_(3)对CaSO_(3)的催化作用随温度、浓度变化而改变,温度小于450℃,Fe_(2)O_(3)质量分数大于0.2%时,对氧化反应起到一定催化作用,温度大于450℃及催化剂质量分数低于0.2%时,由温度占主导地位.微观形貌表征显示随着CaSO_(3)被氧化为CaSO_(4),形貌由团簇状转变为柱状,CaCl_(2)即抑制氧化反应也抑制CaSO_(4)的晶型,Fe_(2)O_(3)促进CaSO_(4)结晶的形成.实验室升温较快,温度大于400℃时,脱硫灰5 min内部温度大于500℃,此时,CaSO_(3)转化率超过85%,中试升温较慢,没有这一特征;吉布斯自由能计算结果表明最有可能发生的是CaSO_(3)氧化反应,600℃以下钙的分解反应不可能发生;CaSO_(3)氧化过程中活性位点的数量与温度有关,当温度在623~723 K时,该反应为一级反应,当温度大于723 K时,反应在5 min左右迅速完成,无法确定其反应级数.Considering the variation in dry heat oxidation of CaSO_(3) in sintering semidry desulfurization ash under different reaction conditions,the effects of temperature,O_(2) content and flow rate in gas,calcium compounds,iron oxide(Fe_(2)O_(3)),water vapor content,and flow rate on CaSO_(3) oxidation were evaluated.It was determined that the reaction adheres to the Arrhenius equation.The oxidation rate of CaSO_(3) increases from 380℃.Moreover,at 450℃,the oxidation rate of CaSO_(3) exceeds 90%,and at 550℃,it is completely oxidized(98.2%).Under the condition of 10℃·min^(-1) in the air atmosphere,the gas flow rate of 450℃and 75 mL·min^(-1) is the optimal process condition for economic dry heat oxidation.Water vapor is present on both sides of the CaSO_(3) oxidation reaction.Moreover,the oxidation of CaSO_(3) by calcium oxides was inhibited by inhibiting the generation of O_(2)^(-) and SO_(3)^(-) free radicals.The order of the inhibition of CaSO_(3) oxidation by the three calcium oxides from weak to strong was CaCO_(3)<Ca(OH)_(2)<CaCl_(2).The catalytic effect of Fe_(2)O_(3) on the oxidation of CaSO_(3) varies with temperature and concentration.When the temperature is less than 450℃and the weight percentage of Fe_(2)O_(3) is greater than 0.2%,it plays a certain catalytic role in the oxidation reaction.The doping of Fe_(2)O_(3) accelerates the formation of O_(2)^(-) and SO_(3)^(-) free radicals.When the temperature exceeds 450℃and the catalyst concentration is less than 0.2%,the catalyst concentration has no effect on the reaction process,and the temperature takes precedence.The microscopy analysis reveals that with the oxidation of CaSO_(3) to CaSO_(4),the morphology shifts from cluster to column.Furthermore,CaCl_(2) inhibits not only the oxidation reaction but also the crystal form of CaSO_(4).Fe_(2)O_(3) aids the formation of CaSO_(4) crystals.When the temperature exceeds 400℃,the internal temperature of desulfurized ash is higher than 500℃for 5 min.Simultaneously,the conversion rate of CaSO_(3) is gr

关 键 词：半干法脱硫 脱硫灰 亚硫酸钙 干热法 氧化特性 

分 类 号：X701.3[环境科学与工程—环境工程]