Abstract
Dimethyl ether (DME) is traditionally produced by methanol dehydration in an adiabatic reactor. Recently, a more economical method has been proposed to produce DME in a reactor in which methanol production and dehydration take place simultaneously on a bi-functional catalyst. In the present study, the design and optimization of an industrial scale fixed bed reactor for the direct synthesis of DME from syngas are investigated. A steady state, pseudo-homogeneous model has been applied to simulate the proposed reactor. At first, the preliminary design of the reactor is done based on the reactor design heuristics for industrial reactors. Then, using differential evolution (DE) algorithm as a fast and efficient optimization method, the tentative reactor operating conditions and its internal configuration are optimized. The objective of the optimization is to maximize DME production in each tube of the reactor. The number of tubes, feed inlet and coolant water temperatures are considered as decision variables of the optimization algorithm. At the optimum conditions, the reactor size decreases due to increase of CO conversion and DME productivity in each tube. The results show that the proposed optimum reactor is more economical for large-scale production of DME in comparison to the conventional industrial DME reactor.