冶炼烟气干法脱硫过程中CaS与SO_2反应的实验及机理研究  

Experimental Studies and Mechanism of CaS and SO_2 Reaction during Smelting Gas Dry Desulphurization Processes

作　　者：昌晶[1] 张聪[2] 田红景[2,3] 郭庆杰[2] 吴卫泽[3] 

机构地区：[1]青岛农业大学资源与环境学院,山东青岛266109 [2]青岛科技大学化工学院,山东青岛266042 [3]北京化工大学化工资源有效利用国家重点实验室,北京100029

出　　处：《高校化学工程学报》2016年第1期240-247,共8页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金(51106077);山东省自然科学基金(ZR2015PE026);化工资源有效利用国家重点实验室开放课题(CRE-2013-C-302);国家级大学生创新创业训练计划(201510435047)

摘　　要：将硫化钙和石英砂机械混合作为脱硫剂,在石英固定床反应器中考查了反应温度、空速、脱硫剂颗粒粒径、有无氧气存在和循环次数对脱硫剂脱除冶炼烟气中SO_2气体性能的影响。较高反应温度、较低烟气空速和较小颗粒粒径均可提高脱硫剂的脱硫率。温度500℃、空速250 h^(-1)条件下,脱硫率在100 min内均保持在96.4%以上。脱硫剂在无氧和有氧条件下循环实验中表现出的脱硫活性均较为稳定。随循环次数的增加,脱硫剂颗粒的比表面积和吸附量缓慢减小,分别从反应前的32.2 m^2×g^(-1)和21.6 cm^3×g^(-1)降至10次循环后的26.5 m^2×g^(-1)和16.2 m^3×g^(-1),而颗粒平均粒径逐渐增加。基于Gaussian 09程序,采用密度泛函理论(DFT)对Ca S与SO_2反应脱硫的微观机理进行了研究,在B3LYP/6-311G+(d,p)水平上优化得到反应物、中间体、过渡态和产物的几何构型,对各驻点进行了单点能计算。中间体IM4到产物P(Ca SO_4+S_2)的过程被推测为反应的速率控制步骤。A mixture of calcium sulfide and quartz sand was used as desulfurizer to remove sulfur dioxide from smelter off-gas in a quartz fixed-bed reactor. The effects of reaction temperature, space velocity, particle size, presence of oxygen and cycle repetition on the desulfurization efficiency were studied. The results show that high temperature, low space velocity and small desulfurizer particles are beneficial to improve desulfurization efficiency. The desulfurization efficiency is above 96.4% when studied within 100 mins under 500℃ and a space velocity of 250 h^-1）. The desulfurizer shows a stable reactivity in the multi-cycle tests both in the presence and absence of oxygen. The specific surface area and adsorption capacity decrease slowly from 32.2 m^2·g^-1 and 21.6 cm^3·g^-1 before the recycle tests to 26.5 m^2·g^-1 and 16.2 cm^3·g^-1 after ten cycles, respectively. However, the particle size increases gradually. The mechanism of the Ca S and SO2 reaction was studied using the density functional theory（DFT） of the Gaussian 09 software. The configurations of reactants, isomers, transition states and products were optimized at the B3LYP/6-311G＋（d,p） level and the single point energy of each stationary point was calculated. The reaction of IM4（intermediate） turns into P（Ca SO4＋S2）（product） was predicted to be the rate-limiting step.

关 键 词：硫化钙(CaS) 冶炼烟气 脱硫 反应机理 

分 类 号：X511[环境科学与工程—环境工程]