Performance of ZSM-5 Catalyst in the Dimethyl Ether to Olefins Process

Sardesai, Abhay; Tartamella, Timothy; Lee, Sung‐Gyu

doi:10.1080/10916469908949718

Cited by 9 publications

(4 citation statements)

References 9 publications

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“…This process has been studied in great detail [45][46][47][48][49][50][51][52][53][54]. Research studies have also been conducted to examine the conversion of dimethyl ether into gasolinerange hydrocarbons [55][56][57], lower olefins [58][59][60][61], and methyl acetate [62]. Research efforts by Air Products and Chemicals in this area have been mentioned [63].…”

Section: Introductionmentioning

confidence: 99%

Liquid phase methanol and dimethyl ether synthesis from syngas

2005

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The Liquid Phase Methanol Synthesis (LPMeOH TM ) process has been investigated in our laboratories since 1982. The reaction chemistry of liquid phase methanol synthesis over commercial Cu/ZnO/Al 2 O 3 catalysts, established for diverse feed gas conditions including H 2 -rich, CO-rich, CO 2 -rich, and CO-free environments, is predominantly based on the CO 2 hydrogenation reaction and the forward water-gas shift reaction. Important aspects of the liquid phase methanol synthesis investigated in this in-depth study include global kinetic rate expressions, external mass transfer mechanisms and rates, correlation for the overall gas-to-liquid mass transfer rate coefficient, computation of the multicomponent phase equilibrium and prediction of the ultimate and isolated chemical equilibrium compositions, thermal stability analysis of the liquid phase methanol synthesis reactor, investigation of pore diffusion in the methanol catalyst, and elucidation of catalyst deactivation/regeneration. These studies were conducted in a mechanically agitated slurry reactor as well as in a liquid entrained reactor. A novel liquid phase process for co-production of dimethyl ether (DME) and methanol has also been developed. The process is based on dual-catalytic synthesis in a single reactor stage, where the methanol synthesis and water gas shift reactions takes place over Cu/ZnO/Al 2 O 3 catalysts and the in-situ methanol dehydration reaction takes place over c-Al 2 O 3 catalyst. Co-production of DME and methanol can increase the single-stage reactor productivity by as much as 80%. By varying the mass ratios of methanol synthesis catalyst to methanol dehydration catalyst, it is possible to co-produce DME and methanol in any fixed proportion, from 5% DME to 95% DME. Also, dual catalysts exhibit higher activity, and more importantly these activities are sustained for a longer catalyst on-stream life by alleviating catalyst deactivation.

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Section: Introductionmentioning

confidence: 99%

Liquid phase methanol and dimethyl ether synthesis from syngas

2005

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“…The UA researchers, since 1985, carried out process development studies in various fundamental and applied aspects, i.e., demonstration of process feasibility, intrinsic kinetics, process chemistry, thermodynamic analysis and development of a software package for combined phase and chemical reaction equilibria for this multiphase and multicomponent system (which enables one to compute the concentrations of dissolved syngas components in the liquid solvent phase, at given reaction conditions), external mass transfer analysis, thermal stability, and scale-up [4][5][6][7][8]. The UA researchers' also first conceived the direct one-step DME synthesis process, termed as LPDME tm process [9][10][11][12] and later, the DME-to-olefins and DME-to-hydrocarbons processes [13][14][15][16], both enhancements over Mobil Oil's original methanolto-gasoline and methanol-to-olefins process [17][18][19][20]. The APCI component has been more focused on catalyst deactivation studies and feasibility/demonstration studies on the pilot scale (5 TPD & 10 TPD scale), of the LPMeOH tm and LPDME tm processes, at its Alternative Fuels Development Unit (AFDU) in LaPorte, Texas [21][22][23][24].…”

Section: Review Articlementioning

confidence: 99%

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

Gogate

2018

PPS

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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.

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“…Based on the preliminary DME-to-lower olefin studies (Sardesai et al, 1998;Sardesai et al, 1999), it was determined that H-ZSM-5 type zeolite catalysts of lower acidity (high SiO 2 /Al 2 O 3 ratios) are instrumental in higher olefin selectivities. The H-ZSM-5 catalyst used in this study is a commercial catalyst supplied by Zeolyst, Inc.…”

Section: Catalystmentioning

confidence: 99%

Alternative Source of Propylene

Sardesai

Lee

2005

Energy Sources

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Synthesis gas derived from natural gas, coal, biomass or any other hydrocarbon source can be advantageously utilized to produce propylene. The approach adopted by the current investigation carries out the conversion of syngas in two stages: singlestage dimethyl ether (DME) synthesis followed by dimethyl ether conversion. Singlestage DME synthesis is carried out in the liquid phase utilizing the synergistic effect of dual catalysts, Cu/ZnO/Al 2 O 3 and γ -alumina. Dimethyl ether produced by this process is then converted to propylene using a shape-selective H-ZSM-5 catalyst. Very high selectivity towards propylene (as high as 68 wt%, the rest being ethylene and butenes) can be achieved by using this catalyst at appropriate reaction and feed conditions. In general, higher temperatures, low partial pressures of DME in the feed, and short contact times used over a H-ZSM-5 catalyst with low acidity increase the selectivity of DME conversion to propylene by inhibiting competing as well as successive reactions which would otherwise form other olefins, paraffins and aromatics. This article describes at length the second stage of the overall syngas-topropylene process, focusing on the conversion of dimethyl ether to propylene over a wide range of reaction and feed conditions.

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Performance of ZSM-5 Catalyst in the Dimethyl Ether to Olefins Process

Cited by 9 publications

References 9 publications

Liquid phase methanol and dimethyl ether synthesis from syngas

Liquid phase methanol and dimethyl ether synthesis from syngas

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

Alternative Source of Propylene

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