Simulation of Dimethyl carbonate production process

Increasing population of the world, along with the growth of solid wastes and industrial activities, has led to the arrival of various contaminants and emissions of pollutants and greenhouse gases to the water, soil and atmosphere. Greenhouse gases such as CO₂ are considered as effective materials in global warming due to the high absorptivity. Hence, researchers seek solutions to reduce the amount of CO₂ in the atmosphere. One of the most applicable methods is utilization of carbon dioxide in chemical processes. In the present thesis, the implementation of carbon dioxide in two-stage dimethyl carbonate production process has been investigated by Aspen HYSYS 10. In this process, ethylene oxide reacts with CO₂ and during the reaction between produced ethylene carbonate and methanol, dimethyl carbonate and ethylene glycol produce. In this research, the affective parameters of the process including temperature, residence time, feed ratio and recycle ratio were evaluated. It was observed that increasing the temperature from 140°c to 160°c resulted in an increase in the reaction rate but after a temperature of 160°c the reverse reaction was predominant to reach its thermodynamic equilibrium. Increasing residence time leads to an increase in conversion percent. The simulation results also showed that the maximum conversion has been obtained in mass ratio of methanol to ethylene carbonate of 8 %. In addition, increasing the recycle ratio has negative effect on EC conversion. The interaction of the above parameters was studied by Design Expert 11 and the optimum amount of effective parameters for production of dimethyl carbonate were obtained as follows: temperature of 160 ° c, the recycle ratio of 0.2, the residence time of 135 min, and feed ratio of 8.5 % that lead to conversion of 64.1 %.