The Effects Of Micromixing On The Rearrangement Reaction Of Cyclohexanone Oxime

The Beckmann rearrangement of Oxim is an important process during the production of caprolactam. It plays an important role in the yield and quality of the production. Because of the quick reaction speed and the high viscosity of rearrangement mixture, the reaction of rearrangement is controlled not only by the reaction kinetics, but also by the micromixing. The main purpose of this paper is to provide theoretic supporting and instruction of the industrial process by making a reaction kinetics model and a micromixing reaction model. The paper is composed of two main parts. In the first part, the establishment of reaction kinetics model is described, and the second part is about the micromixing reaction model. The rearrangement reaction of Oxim is a typical Beckmann rearrangement reaction. Because the kinetics of Beckmann rearrangement is very complicated and the reaction speed is very fast, the realization of its reaction kinetics is very variant. It's not satisfactory to use the present kinetics directly to explain the industrial rearrangement process. In charpter one, the kinetics of Beckmann rearrangement reaction of the production of caprolactam has been studied. We used the hypothermia reaction data cited by the literature, Six kinetic models were proposed based on the possible radical reaction mechanisms and reasonable simplification. By employing the optimization technique, the optimum kinetic model was suggested. The calculation values of the model agreed well with the literature data. The model also agreed to the real industrial phenomenon. By studding of the kinetics of rearrangement, we know that the rearrangement reaction is very fast. It can be completed in 2mS. General speaking, the fast reaction in liquid phase are all affected by micromixing, so it's necessary to observe how dose micromixing affect the rearrangement reaction. In charpter two, slice structure model theory was introduced to analyse and describe the chemical reactions during different mixing stages, by which we divide it into three regions, the material scatter region, the micromixing region and the macromixing region. These three regions correspond to the state of complete segregation, partial segregation and maximum mixedness respectively. We can draw a conclusion by math analysis that only a little material is consumed in the material scatter region, and the chemical reaction mainly take place in the micromixing region, it won't last to the macromixing region. Because of this reason, we can know that the chemical reaction should be controlled by micromixing region. Corresponding micromixing reaction slice model is established by using the kinetics model mentioned in chapter one and the slice structure theories. This model can be descriped as a system of partial differential equations which has infinite space region. Through analysis, such infinite space can be transformed into an enough finite space region. We can resolve the model with suitable calculation method (Method of line). Then we can know that under the condition of micromixing, the real rate of H2S04 and Oxim where chemical reactions happened is much less than the macro rate (1.5), and it inevitably leads to some partial aggravation. We can consider the affection caused by the micromixing in the practical course both in quality and quantity with this model. Some factors contributed to micromixing are simulated and...