关键词: 微观混合, 非牛顿流体, 粘度, 平行竞争反应

Abstract: The influence of viscosity on the micromixing of non-Newtonian fluid was investigated by using parallel competing reactions. The experiments were carried out in a stirred tank of 0.476 m diameter agitated by a Rushton turbine. Hydroxyethyl cellulose (HEC 250-HHX) water solution at 0.1% and 0.5% (w) concentrations was used as viscous fluid in the experiments. The two parallel competing reaction systems (reaction of cupric sulfate and sodium hydroxide competing with alkaline hydrolysis of ethyl chloroacetate) as working system were improved and successfully applied in the viscous fluid as working reactions. The effects of feeding time, impeller speed, feeding position and viscosity on the yields of by-product (XQ) were investigated. The experimental results show that XQ strongly depends on the viscosity of the liquid. XQ increases greatly as the viscosity of HEC solution increases. As expected, feeding at the impeller region has a lower XQ than feeding at the liquid surface due to the difference of local energy dissipation. The results are of importance to the optimum design of stirred reactors with non-Newtonian fluid of high viscosity.

Key words: micromixing, non-Newtonian fluid, viscosity, parallel reaction