蜜胺浆液吸收低浓度SO_2动力学研究

Kinetics of Absorption of Sulfur Dioxide into Melamine Slurry

本文采用双全混搅拌反应器,对蜜胺浆液吸收低浓度SO_2气体这一气、液、固三相反应过程的规律进行了研究。通过理论分析和实验考察,证明在该三相反应过程中,SO_2与蜜胺的化学反应是在极其靠近气液界面的液膜内进行的瞬时反应;SO_2在气相中的传质为三相反应过程的速率控制步骤。该三相反应过程的动力学模型可简化为: N_A=k_(Ag)p_A 并且用实验证明了该模型的正确性。通过对实验数据回归,得到了双全混搅拌反应器中气相传质系数的关联式: k_(Ag)=1.2706×10^(=5)+8.1108×10^(=9)

A series of experiments of absorption of SO_2 into melamine slurries were conducted under various experimental eonditione in a double-mixed contactor with a plane gasliquid interface in order to clarify the mechanism of absorption of SO_2 into melamine slurry and to develop a mathematical model to deserice this process based on the film concept. It was found that the dissolution of solid melamine in the liquid film near the gas-liquid interface was negligible. Furthermore, the rate of absorption of SO_2 into melamine slurries was almost not affected by the dissolution of solid melamine, the transport of dissolved melamine and SO_2 in the liquid phase. The absorption process was mainly controlled by the transport of SO_2 across the gas film. Thus the model for hhree-phase reaction process can be simplified as: N_A=k_(Ag)P_(Ag) A number of experiments were carried out to check the accuracy of the above equation. The results showed that the model was feasible and can be employed to describe this process. An emperical relationship for k_(Ag) in this type of reactors was proposed by correlating the experiment data obtained in this study: k_(Ag)=1.2706×10^(-5)+8.1108×10^(-9)Re