Improving the conventional reactor/separation/recycle DME process

- The DME process proposed in a recent paper is improved by two modifications.
- A vaporizer is used in the liquid feed preheat system instead of a furnace.
- A cooled reactor is used instead of an adiabatic reactor to improve conversion.
- The improved process is economically superior to the published process.
- It is even more attractive than the published reactive distillation process.

The conventional process to produce dimethyl ether (DME) by the dehydration of methanol is a classical example of a chemical process with a reaction section, a separation section and recycles of material and energy connecting the two. Alternative processes have been explored in attempts to increase process intensification. A recent paper claims that reactive distillation can reduce capital investment and energy costs when compared to a conventional reactor/separation/recycle process.The purpose of this paper is to demonstrate that the conventional process can be significantly improved to the point that it is much superior to the published conventional process and is even more economical than the published reactive distillation process. The proposed flowsheet requires more capital investment (53%) than the reactive distillation process but saves 38% in energy costs, which produces an attractive 61% return on the larger capital investment.