The Direct Dimethyl Ether (DME) Synthesis Process from Syngas: Current Status and Future prospects I. Process Feasibility and Chemical Synergy in LPDMEtm Process

Abstract

A novel one-step process for co-production of dimethyl ether (DME) and methanol, in the liquid phase was first conceived by the UA researchers, as an advance over the liquid phase methanol synthesis process (LPMeOH tm ). The one-step, direct DME process (LPDME tm ) is based on the application of "dual catalysis", where 2 functionally different yet compatible catalysts are used as a physical mixture, well-dispersed in the inert liquid phase. Three different reactions, methanol synthesis (via CO and CO 2 ), water-gas shift, and methanol dehydration (to form DME) take place over the 2 catalysts, Cu/ZnO/Al 2 O 3 and typically γ-Al 2 O 3 . The favorable thermodynamic and kinetic coupling of methanol dehydration reaction (very rapid and at/near thermodynamic equilibrium) with the methanol synthesis reaction (slower kinetics and highly thermodynamic) leads the beneficial "chemical synergy". This synergy helps to overcome the limitation on thermodynamic equilibrium conversion, and increases the per-pass syngas conversionand reactor productivity. The catalyst deactivation phenomena in LPDME tm processes also greatly alleviated compared to methanol alone; the increase in syngas conversion and methyl equivalent productivity (MEP) are sustained over a longer on-stream time.Here, we review the salient developments in the LPDME tm process since its inception, first at UA research laboratories and elsewhere including Air Products and Chemicals, Inc. First, we demonstrate the rationale of the LPDME tm process, and outline briefly the research studies in the two processes, that illustrate the chemical synergy in the LPDME tm process. This successful example of "cooperative catalysis" can be adapted in principle to many other organic reactions. We then briefly discern the intrinsic kinetics of the LPMeOH tm and LPDME tm systems, and also shed light of the catalyst deactivation phenomena in these processes. In closing, we outline the reactor design/scale-up and plant operational experience of the 3 commercial technologies, as currently practiced by JFE holdings, BP-AMOCO, and Halder-Topsoe.

Present and Future Perspectives of Liquid-Phase Slurry Processes Involved in Methanol and Dimethyl Ether Synthesis Using Biomass-Derived Syngas

“…The direct process at a high temperature suffers from low H 2 and CO conversion per pass, which leads to a low yield of DME, while a high yield of CO 2 . , Also, further downstream separation of vapors of DME and CO 2 require a high processing cost. Lately, slurry technology in the LPMeOH process showed some benefits over the conventional gas-phase process by handling the single-step DME production in one reactor and maintaining the temperature. ,,,, The LPMeOH process of DME production also had advantages of managing the WGS reaction and converting byproduct water into H 2 , thereby increasing conversion of syngas and, in turn, increasing productivity of methanol and DME.…”

“…Lately, slurry technology in the LPMeOH process showed some benefits over the conventional gas-phase process by handling the single-step DME production in one reactor and maintaining the temperature. 14,37,82,22,83 The LPMeOH process of DME production also had advantages of managing the WGS reaction and converting byproduct water into H 2 , thereby increasing conversion of syngas and, in turn, increasing productivity of methanol and DME.…”

“…The combination of more than one catalyst is mainly used in combined processes of methanol and DME and/or any other biofuel. , A hybrid catalyst has recently been recognized as one of the most advantageous catalysts for the direct synthesis of DME in a single reactor. Traditionally utilized hybrid catalysts for DME production are Cu–Zn–Al-type catalysts and acidic zeolite or alumina for methanol dehydration .…”

“…for public interest to share the performance and economic analysis of the commercial-scale demonstration of LPMeOH technology. In later years, a few research groups provided research articles − and review reports ,, on recent studies on slurry-phase technology for gas-to-liquid processes. The effects of various flow parameters on hydrodynamic properties of a methanol slurry reactor have been studied and discussed in detail.…”

Effect of Dimethyl Ether (Dme) as LPG Substitution on Household Stove: Mixture Stability, Stove Efficiency, Fuel Consumption, and Materials Testing

“…Coal and biomass wastes are processed through gasification into syngas [3]. Natural gas is converted into syngas through the reforming process, steam reforming, partial oxidation, and auto-thermal reforming [4], [5]. The partial oxidation reaction is more efficient than the steam reforming process due to the energy surplus.…”