Investigation of operating conditions effect on dimethyl ether production by methanol

In this study, the process of Dimethyl ether (DME) production by Methanol (MeOH) was simulated. The UNIQUAC and Peng-Robinson equations were applied as activity model and equation of state in the simulation model, respectively. To evaluate the effect of operational parameters on DME production, the impact of reactor temperature and dimensions, distillate rate, and reflux ratio from two distillation columns were investigated. The results indicated that with an increase in the reactor residence time, a maximum conversion of ۸۵% is achieved for all studied temperature ranges. Results showed that by increasing the first distillation column (T-۱۰ column) feed flow rate from ۱۳۰ kmol/h to ۱۷۰ kmol/hr, the purity of DME decreases by about ۴۰%, but the recovery rate of DME enhances by about ۳۰%. Furthermore, changes in the reflux ratio of the T-۱۰ column in the range of ۰.۳۵ to ۰.۸ showed a low effect on the DME purity and recovery. Also, it was observed that with enhancement of T-۱۰ column distillate rate from ۱۱۰ kmol/h to ۱۳۰ kmol/h, the reactor conversion increased by about ۷%. Upon raising the flow rate of recycle stream from ۵۰ kmol/h to ۲۵۰ kmol/h, the reactor conversion and DME purity in the product stream decrease about ۴۵% and ۲۰%, respectively. Finally, using genetic algorithm (GA) method, the operational conditions were optimized to reach maximum purity of DME in the final product. Results showed reflux ratio of second distillation column has the main effect at enchantment of product DME purity.

Keywords:

Dimethyl ether (DME) process , methanol , Simulation , Genetic Algorithm (GA) optimization