一种酚类抑制剂对亚硫酸镁氧化反应动力学的影响及作用机理  

Mechanism and Effect of a Phenol Inhibitor on the Oxidation Kinetics of Magnesium Sulfite

作　　者：汪黎东[1,2] 马永亮[2] 郝吉明[2] 张雯娣[1] 袁钢[2] 

机构地区：[1]华北电力大学环境科学与工程学院,保定071003 [2]清华大学环境科学与工程系,北京100084

出　　处：《化学学报》2011年第10期1160-1166,共7页Acta Chimica Sinica

基　　金：国家863重点(No.2007AA061703);教育部重点(No.109157);中央高校基本科研业务费专项资金(No.10MG35)资助项目

摘　　要：亚硫酸镁的氧化是湿式镁法烟气脱硫过程中的重要步骤.通过实验筛选出一种新型酚类抑制剂(T),可显著延缓亚硫酸镁的氧化反应速率.在接近实际工况条件下,研究了抑制剂浓度、亚硫酸镁浓度、氧分压、pH、温度等条件对亚硫酸镁氧化速率的影响.结果表明,抑制剂T、溶解氧及亚硫酸镁的分级数分别为—0.25,0.5和0,反应的表观活化能为48.2kJ·mol-1.结合建立的三相反应模型,对T抑制条件下的总反应过程进行了推断,认为亚硫酸镁氧化的本征化学反应在贫氧区进行,而总反应速率受氧的传质扩散过程控制.与非抑制条件下的结果相比,T的存在降低了本征反应速率,进而使氧的传质速率减小.研究结果为利用抑制氧化手段实现脱硫副产物回收提供了有益参考.Magnesium sulfite oxidation is an important step in the wet magnesia flue gas desulphurizationprocess. In this paper, a novel phenol inhibitor, T, is selected by comparison experiments that could slow down the oxidation rate of magnesium sulfite greatly. Effects of inhibitor concentration, magnesium sulfite concentration, oxygen partial pressure, pH and temperature, on the oxidation rate were studied under the condition close to the practical. The results show that the reaction orders for inhibitor T, dissolved oxygen and magnesium sulfite are —0.25, 0.5 and 0, respectively. And the apparent activation energy is 48.2 kJ·mol-1. Integrated with the three-phase reaction model, the general reaction process was deduced. It is con-cluded that the intrinsic chemical reaction takes place in the poor oxygen zone and the general reaction rate is controlled by the oxygen diffusion. Compared with the results under the uninhibited conditions, the pres-ence of T delays the intrinsic reaction rate, resulting in the decrease of oxygen diffusion rate. Thus the result provides a useful reference for recycle of byproduct by inhibited oxidation in magnesia desulphurization.

关 键 词：酚类抑制剂 亚硫酸镁 氧化 动力学 脱硫 

分 类 号：O643.1[理学—物理化学]