Experimental ADN Numerical Simulation Study Based On Continuous Production Equipment Of Isopropenyl Acetate

Traditional pharmaceutical and fine chemical production are mainly batch processes based on stirred reactor,such as synthesis of isopropenyl acetate with acetone and ketone as raw materials.In the production process of isopropenyl acetate,poor gas-liquid mixing effect,limited ventilation and low conversion rate are the main problems.In order to improve the original production mode,the paper proposes to apply the loop reactor to the production of isopropenyl acetate to realize continuous production,and to lay the foundation for further improving the automation and information of the production device.The successful research will provide ideas and reference for the continuous production process transformation or development of non-rapid reaction fine chemical products of liquid and micro-positive pressure gas.The key to realize the continuous production of isopropenyl acetate is to optimize the performance of venturi ejector,the core equipment of jet loop reactor.In the paper,the gas induction of venturi ejector parameters that affect bubble size parameters.Firstly,the basic experiment of isopropenyl acetate was carried out,and the pilot test platform of jet loop reactor was built.The influence of operation parameters and physical parameters on suction performance was investigated.Finally,the distribution of bubble size at venturi ejector outlet was investigated by numerical simulation,and the effect of bubble size on gas-liquid mass transfer was analyzed.The following conclusions can be drawn:（1）The optimum reaction conditions of acetone and ketene were obtained by the basic experiment: reaction time 3 h,reaction temperature 50～55 ℃,catalyst dosage1.5 %（acetone volume calculation）;（2）Pilot experiments with water-air show that gas induction of the ejector increases with the increase of the gas inlet pressure and liquid circulation,and decreases with the increase of the internal pressure of the reactor.The continuous pilot test was carried out with acetone-ketone.The content of isopropenyl acetate reached more than 60% in the continuous process,which solved the problem of ketone with slight positive pressure and the difficulty of gas induction.It was found that the ketone gas intake was greater than the air gas intake by co MParing the two systems in the experiment.（3）The gas density of different systems has the greatest influence on the suction performance of venturi injector,followed by the liquid density,and the fluid viscosity has the least influence on the suction performance;（4）The operating parameters will affect the size distribution of the bubbles at the outlet of the venturi ejector.The coupled population balance model is used to solve the problem.The results show that the smaller the liquid inlet velocity or the gas inlet pressure is,the larger the proportion of small bubbles is,and the contact between the gas and liquid phases will be higher.The larger the area,the more favorable the gas-liquid mass transfer;as the outlet pressure decreases,the proportion of small bubbles gradually decreases,which is not conducive to the gas-liquid mass transfer.