(149b) A Mini-Pilot Scale Demonstration of Single-Stage Syngas-to-DME Process

A fully continuous, proof-of-concept mini-pilot scale system for a process engineering study of the single-stage syngas-to-dimethylether (DME) process has been designed and fabricated on a self-enclosed mobile platform. The process feasibility and superior reactivity of our carbonate modified synthesis catalyst for co-production of methanol and DME is to be demonstrated on the system. The mini-pilot system is composed of four seamlessly-integrated principal sections of (1) a feed syngas blending and compression system, (2) a mechanically agitated slurry reactor system, (3) a product separation, collection and analysis system, and (4) a data acquisition and control system. The entire system can be operated from the outside of the enclosed unit and is in principle remote-controllable. The heart of the reaction section is a one-liter Parr Systems® bolt-closure reactor body (Model No. 4520) with a magnetic drive assembly installed. The effluent gas is analyzed using a Thermo-Fisher’s gas chromatograph (GC)-thermal conductivity detector (TCD). The temperature and pressure of the reactor system are monitored and controlled real-time by the Labview® data acquisition and control system. For the operational safety of the system, a safety rupture disc is installed, an inert nitrogen flush system is implemented in case of power disruption, and three combustible gas monitors with audible and visible alarms are mounted at the pre-determined locations in and outside of the system. Since both methanol and DME catalysts used in the process operation are of fine particulates of -170 U.S. Standard mesh, the dual catalytic reaction system is operated in a regime which is free from pore diffusional limitation. The catalyst loading ratio between the methanol synthesis catalyst and the methanol dehydration catalyst is directly correlated with the product selectivity between methanol and DME. This study is meant to establish the superior processability of our carbonate-based catalyst system over the conventional oxide-based catalyst system, especially in handling a syngas feed that is substantially richer than the optimal concentration of carbon dioxide.