The Deactivation Modes of Cu/ZnO/Al2O3 and HZSM-5 Physical Mixture in the One-Step DME Synthesis

Barbosa, Flávia S. R.; Ruiz, Vanusa S. O.; Monteiro, J.L.F.; Avillez, Roberto R. de; Borges, Luiz Eduardo Pizarro; Appel, Lucia G.

doi:10.1007/s10562-008-9601-7

Cited by 27 publications

(8 citation statements)

References 18 publications

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“…CO conversion and CO 2 selectivity calculated based on the first stage were almost the same as those based on the second stage. In addition, CO 2 selectivity was similar to that in the process of one-step synthesis of DME from syngas reported elsewhere [25,26]. Thus, it can be drawn that CO conversion and CO 2 selectivity were governed by the first stage and hardly influenced by the second stage.…”

Section: Effect Of Reaction Temperature In the Second Stagesupporting

confidence: 83%

Synthesis of LPG via DME from syngas in two-stage reaction system

et al. 2013

Fuel Processing Technology

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Section: Effect Of Reaction Temperature In the Second Stagesupporting

confidence: 83%

Synthesis of LPG via DME from syngas in two-stage reaction system

et al. 2013

Fuel Processing Technology

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“…7b). The fact that the product selectivity remained constant with TOS (and with values approaching those of the thermodynamic equilibrium) suggests that for the above three catalysts within the G-series the observed decrease in CO conversion (much more pronounced for the catalyst comprising the Coexchanged zeolite) should be mostly related to a certain deactivation of the Cu-based methanol synthesis component [36,37]. Interestingly, a distinct selectivity behavior with TOS was found for the catalyst comprising the Na-exchanged Na39HZ sample, as evidenced in Fig.…”

Section: Influence Of Zeolite Acidity On Methanol Dehydration Activitymentioning

confidence: 90%

Direct synthesis of DME from syngas on hybrid CuZnAl/ZSM-5 catalysts: New insights into the role of zeolite acidity

García‐Trenco

Martı́nez

2012

Applied Catalysis A: General

137

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A commercial HZSM-5 zeolite (Si/Al=16) was submitted to mild acid treatment and we have found that different conclusions regarding the effect of zeolite acidity may be reached depending on the specific method used for preparing the hybrid catalysts when the overall STD process becomes controlled by the methanol synthesis rate on the Cubased catalyst (i.e. using hybrids with a CZA:zeolite mass ratio of 2:1, that is, with an "excess" of acid sites). Thus, for hybrids prepared by mixing the pre-pelletized components, the same CO conversion and product selectivity (with values approaching those predicted by the thermodynamic equilibrium at the studied conditions) with no signs of deactivation during at least 50 h on stream was attained irrespective of the zeolite acidity. By contrast, significant differences in catalyst stability were found for hybrids prepared by grinding the component powders prior to pelletizing, pointing towards the occurrence of detrimental interactions between the CZA and zeolite components during the grinding preparation stage. Moreover, the different TOS behaviors observed between these hybrids depending on the particular zeolite used suggested that the kind and extent of such detrimental interactions should be tightly related to the acidity and/or chemical composition of the ZSM-5 zeolite.

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“…At the same time, water is known to attenuate coke formation and deposition over both functions of the hybrid catalysts [16,17]. Furthermore, formation of hydrocarbons in parallel with methanol synthesis [18,19] or methanol dehydration [20] can eventually lead to carbon compounds deposition and deactivation of both functions of the hybrid catalyst.…”

Section: Ch 3 Oh(g)mentioning

confidence: 99%

Direct dimethyl ether synthesis from synthesis gas: The influence of methanol dehydration on methanol synthesis reaction

et al. 2016

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Direct dimethyl ether (DME) synthesis from synthesis gas is studied with regard to potential effects of methanol dehydration on methanol formation and copperbased catalyst performance. For this, the influence of the operating conditions (space velocity, temperature, pressure, time-on-stream and syngas composition) on activity, selectivity and stability of the catalyst was studied and compared for methanol synthesis and direct DME synthesis. The advantage of the direct over the two-step DME synthesis is apparent at conditions where syngas conversion to methanol is thermodynamically limited. However, under the applied operating conditions, results suggest that combining methanol synthesis and dehydration has a negative effect on the methanol formation kinetics. The origin of the observed phenomena is investigated by varying dehydration catalyst and by introducing dehydration products (DME and water) into the methanol synthesis feed. Choice of the solid acid catalyst does not seem to affect methanol formation, and DME is also found to be practically inert over the methanol synthesis catalysts. Water injection, on the other hand, led to a significant decrease in the methanol synthesis rate. Thus, formation of an additional amount of water through methanol dehydration might be an explanation for the lower methanol formation rate in the direct DME synthesis.

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The Deactivation Modes of Cu/ZnO/Al2O3 and HZSM-5 Physical Mixture in the One-Step DME Synthesis

Cited by 27 publications

References 18 publications

Synthesis of LPG via DME from syngas in two-stage reaction system

Synthesis of LPG via DME from syngas in two-stage reaction system

Direct synthesis of DME from syngas on hybrid CuZnAl/ZSM-5 catalysts: New insights into the role of zeolite acidity

Direct dimethyl ether synthesis from synthesis gas: The influence of methanol dehydration on methanol synthesis reaction

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