Scaling Up,Optimizing Operation And Determining Safe Operation Conditions For Reaction In Semi-batch Reactor Based On Reaction Calorimetric Studies

The stirring tank has been applied extensively for chemical reactors due to its advantages of flexible operation,simple structure and high efficiency of mass and heat transfer.In the fine chemical and pharmaceutical industries,many strong exothermic reaction processes are carried out in stirred tanks.If the reactor is not handled properly,reactor temperature will run-away.Therefore,it is very important to determine the safe operating conditions in production.The semi-batch mode is generally used to slow the release of heat to avoid thermal runaway.In this paper,a scale-up process from a laboratory scale to industrial-scale semi-batch reactor was established based on the boundary diagram which is obtained from reaction calorimetric studies.During this process,it is necessary to increase the feeding time and the heat transfer area.Then,under the safe conditions,the feeding function and operating temperature of the strong exothermic reaction were simulated and optimized.The sectional constant-speed feeding can shorten the feeding time under the premise of ensuring safe condition,while maintaining a high conversion rate at the end of the feeding.Using large feeding rate and short feeding time at the beginning of the reaction can help to increase the production efficiency.Through simulation,it is found that the feeding material temperature and the pre-placed material temperature have little influence on the reaction process in the semi-batch reactor.Increasing the temperature of the heat transfer medium can significantly increase the conversion rate of the reactants.Finally,based on the relationship between different operating conditions and accumulation curves,a new method for judging the safe operating conditions was established,effectively determining three operating areas:no ignition,thermal runaway and QFS.The influence of different model parameters on this method was also studied.It was found that the reaction order n had a greater influence on this method.The experimental results of RC1 justify the reliability of the conclusion obtained from this new method.