Dimethylether From Coal: Performance Assessment of IGCC Power Plants Integrated With DME Synthesis Processes

It is well known that coal gasification plants allows to produce a clean synthesis gas which can be used as a fuel in IGCC power plants and as a raw material in order to produce hydrogen, methanol, dimethylether (DME) and other chemicals. Recent studies show the growing interest of DME as a new clean fuel for diesel engines, gas turbines, fuel cells and household uses. In this paper, a comparative performance analysis of two different IGCC power plants integrated with a DME synthesis process has been carried out. In particular two different coal gasification processes (a dry-feed and a slurry-feed entrained-flow gasifiers) and the advanced liquid phase DME (LPDME™) synthesis process have been considered. The analysis has been carried out in order to evaluate the influence of the operating parameters of the DME synthesis section (pressure and purge gas recycle ratio) on both DME production and net power output. The performance assessment has shown that, according to both gasification process and DME synthesis parameters, the produced DME accounts for about 40–46% of the coal chemical energy, whereas the net power output of the IGCC-DS plant accounts for about 13–19%. Moreover, the performance assessment also has shown that the IGCC-DS power plants based on the slurry-feed gasification processes lead to an higher DME production and a corresponding lower power output with respect to the solutions based on the dryfeed gasifiers.