A SINGLE-STAGE, LIQUID-PHASE DIMETHYL ETHER SYNTHESIS PROCESS FROM SYNGAS IV. THE WODYNAMIC ANALYSIS OF THE LPDME PROCESS SYSTEM

In the LPDME process, methanol synthesis catalyst (composed of CuO, ZnO, and Al2O3) and the methanol dehydration catalyst (gamma-alumina) are slurried in the inert liquid phase. The catalysts constitute the solid phase. Syngas components (H2, CO, CO2, and CH4) and the products (CH3OH, H2O, and DME) constitute the vapor phase. At least three chemical reactions, viz., methanol synthesis, water-gas shift, and methanol dehydration also occur simultaneously in the liquid phase. The multicomponent phase equilibrium and the simultaneous chemical reaction equilibrium for this process system have been studied. The thermodynamic analysis has been presented in terms of the equilibrium conversions for H2and CO, syngas, and the concentration driving forces for H2 and CO. Methanol synthesis alone and co-production of methanol and DME are compared. The effects of water and CO2addition to the feed syngas on the equilibrium conversions are also investigated.