Dynamic Process Intensification of Dimethyl Ether Reactive Distillation Based on Output Multiplicity

Abstract

Dynamic process intensification technology is an emerging technology of process intensification. It adopts a nonsteady-state operation mode, which can improve the time-averaged performance of the reaction and distillation system without increasing equipment investment. This research proposes to implement dynamic process intensification in reactive distillation (RD) of methanol dehydration to dimethyl ether (DME). The multiplicity of the reactive distillation process is studied by bifurcation analysis, which uses the heat duty of reboiler as a bifurcation parameter and uses the flow rate and mole fraction of the distillate as the dependent variables (state variables). Based on the output multiplicity of the system, the dynamic intensification process for periodically switching the auxiliary products is established. Compared with the steady-state operation, the time-averaged conversion of the system under nonsteady-state operation is increased by 3.49%, and the heat duty of the reboiler is reduced by 6.00 kW. Finally, dynamic optimization (DO) of RD is studied through the control vector parametrization (CVP) method by using conversion and the heat duty of reboiler as the objective functions. The optimal cyclic steady state is obtained when the duration of the operation period with high yield is 1.1 h; correspondingly, the duration of the operation period with high purity is 0.1 h.