Modeling Of A Series Of Nine Stirred Tank Reactors For Caprolactam Synththesis From Toluene

Caprolactam is a kind of important organic chemical material and there is much need in home market. So, discovering the charac -teristic of the core part in the process of caprolactam starting from toluene-reactor for lactamization is important to improve the produ -ct quality and yield, reduce the loss of raw material and cut down the cost and energy, which is of practical significance and academic value. By widely looking into literatures, we got some important technological information.According to the literatures we have looked into, we got reac -tion kinetics information. The mechanism of nitrosation of cyclo-hexane carboxylic acid (CCA) to caprolactam was studied, and the best one by far, which is the steps for conversion of mixed anhydride to caprolactam through the intermediate pentamethylene -ketene. Based on this, the reaction network and kinetics were studi -ed. At last, We thought premixed and nitrosation are second order reaction and the concentration of SO3 and NOHSO4 directly affect the rate of reaction in this system.We developed two mathematical models for two units, which include a complete mixed tank with internal heat exchanger and a series of nine stirred tanks reactor with side feed. We solved two mathematical models using the time-space step disperse andRunge-Kutta.We developed the program for reactor simulation using C language and got the soft for simulating lactamization- reactor. The compare of the modeling result and commercial data shows that the result is well consistent with the industrial data. Using the developed soft, we discussed the effect of operational parameter in the premixed reactor on the reaction. We concluded that the operati-onal press has less affect and the reaction temperature and the quan -tity of oleum is the key parameter. We studied the influence of the feed, the reaction temperature and press in a series of nine stirred tanks reactor on the characteristic of this reactor. We concluded that the operational press has little effect on the reaction and the tempera -ture and the feed of nitroso-sulfuric is the key to control the react -ion process and improve the yield.At last, we got the appropriate operational condition: the ratio of oleum to CCA is 0.35～0.4 and the reaction temperature is contr -oled under 24℃, which makes the process of mix better; the react -ion temperature in the lactamization-reactor is 72℃, operated in normal press and the appropriate feed ratio, which can improve yield and reduce the byproduct.Based on the mass and energy balances and kinetics of chemi-cal reaction, a dynamic model was developed. Simulation results indic -ated that the model can describe the reactor correctly. The information we got is valuable and instructive for optimizing opera -tion and reconstructing the process.