Dehydration of methanol to dimethyl ether in a dual-catalyst system catalytic distillation tower

• A dimethyl ether catalytic distillation (CD) model is setup in the commercial simulation program, Aspen Plus and validated with pilot test data.
• The CD tower design consists of low temperature dehydration catalysts in the upper section of bed and high temperature dehydration catalysts in the lower section of bed.
• The dual-catalyst system results in higher allowable tower pressure and lower catalyst deactivation rate.

A novel design of a dimethyl ether (DME) catalytic distillation (CD) tower is explored. Due to the wide boiling range among the reaction mixture components: water, methanol and DME, a dual-catalyst system CD tower is designed to minimize the tower temperature and catalyst deactivation rate. A DME CD tower model was developed and validated with both VLE data and pilot test data, and the model so obtained agrees with the results published by An et al. The dual-catalyst system CD tower, wherein the upper section of bed is loaded with low temperature catalysts and the lower section of bed is loaded with high temperature catalysts, are arranged such that both catalysts are used at optimum dehydration temperatures and the product DME can still be condensed with normally available cooling water.