Plant-wide design and control of DMC synthesis process via reactive distillation and thermally coupled extractive distillation

In the study, reactive distillation is designed to produce dimethyl carbonate and ethylene glycol by the transesterification of ethylene carbonate and methanol. The products of the reactive distillation column include ethylene glycol and a dimethyl carbonate/methanol mixture, close to azeotropic composition. The azeotrope is separated in the study by pressure-swing distillation and extractive distillation using phenol as an extractive agent. The extractive distillation is found to be much more economical than the pressure-swing distillation. Thermal coupling technology is also implemented between the two columns of the extractive distillation. Thermally coupled extractive distillation provides the best energy efficiency. Proper selection and pairing of controlled and manipulated variables are determined by using steady-state analysis. A simple temperature control scheme is sufficient to maintain stoichiometric balance between the reactant feeds and product purities at or around their designed values for the plant-wide process of reactive distillation + thermally coupled extractive distillation. (C) 2009 Elsevier Ltd. All rights reserved.