An analysis of dimethyl ether synthesis from syngas

Abstract

The dimethyl ether (DME) is an environmentally friendly fuel, that can replace succesfully the petroleum Diesel in engines, or the LPG fuel. In the last period, the world production of DME was steadily rising, with annual rates of 5-8%. The actual commercial technologies producing DME are based on the methanol etherification (the two-step process). An important research effort was expensed in last decennia, in the development of technologies transforming directly the synthesis gas into DME, without separation of the intermediary methanol (the direct or one-step process). This work presents data related to the direct DME synthesis technologies from synthesis gas, thermodynamic particularities of the chemical process and design issues of multi-tubular fixed bed catalytic reactor for gas phase DME synthesis. It is proposed a new constructive solution of the synthesis reactor, with the reactor divided in multiple zones, having distinct catalyst compositions and cooling characteristics. The simulation calculations evidenced the important increase in DME production that can be achieved by this constructive solution, as consequence of an improved control of process evolution along the catalytic reactor.