scholarly journals A Method for Assessing Catalyst Deactivation: A Case Study on Methanol-to-Hydrocarbons Conversion

ACS Catalysis ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 7065-7072 ◽  
Author(s):  
Brandon L. Foley ◽  
Blake A. Johnson ◽  
Aditya Bhan
Keyword(s):  
Catalyst Deactivation ◽  
Methanol To Hydrocarbons

Methanol to hydrocarbons over large cavity zeolites: Toward a unified description of catalyst deactivation and the reaction mechanism

2010 ◽  
Vol 275 (1) ◽  
pp. 170-180 ◽  
Author(s):  
Morten Bjørgen ◽  
Sema Akyalcin ◽  
Unni Olsbye ◽  
Sandrine Benard ◽  
Stein Kolboe ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Catalyst Deactivation ◽  
Large Cavity ◽  
Methanol To Hydrocarbons ◽  
Unified Description

Approaches for minimizing catalyst deactivation in the methanol-to-hydrocarbons reaction over ZSM-5 catalysts

2020 ◽  
Author(s):  
José Valecillos ◽  
Eva Epelde ◽  
Idoia Hita ◽  
Andrés T. Aguayo ◽  
Javier Bilbao ◽  
...  
Keyword(s):  
Catalyst Deactivation ◽  
Methanol To Hydrocarbons

Catalyst deactivation by coke formation in microporous and desilicated zeolite H-ZSM-5 during the conversion of methanol to hydrocarbons

2013 ◽  
Vol 307 ◽  
pp. 62-73 ◽  
Author(s):  
Francesca Lønstad Bleken ◽  
Katia Barbera ◽  
Francesca Bonino ◽  
Unni Olsbye ◽  
Karl Petter Lillerud ◽  
...  
Keyword(s):  
Catalyst Deactivation ◽  
Coke Formation ◽  
Methanol To Hydrocarbons

scholarly journals Surface Characteristics Change of Zinc Modified H-ZSM-5 Zeolites in Methanol to Hydrocarbons Transformation Process

2020 ◽  
Vol 6 (11) ◽  
pp. 23-30
Author(s):  
A. Sidorov ◽  
V. Molchanov ◽  
L. Mushinskii ◽  
R. Brovko
Keyword(s):  
Surface Properties ◽  
Catalyst Deactivation ◽  
Catalyst Activity ◽  
Nitrogen Adsorption ◽  
Surface Characteristics ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Transformation Process ◽  
Methanol To Hydrocarbons ◽  
Nitrogen Adsorption Isotherms

The t-plot method is a well-known method for determining the volumes of micro- and/or mesoporous materials and the specific surface area of a sample by comparison with a reference adsorption isotherm of a non-porous material having a similar surface chemical composition. The article describes the applicability of the t-graph method to the analysis of the surface properties of zinc modified samples of zeolite H-ZSM-5 before and after the reactions of methanol transformation into hydrocarbons occur on them. Zeolites are widely used as catalysts in the petrochemical and refining industries. These materials contain active Bronsted acid sites, distributed within the microporous structure of zeolites, which leads to selective catalysis due to the difference in the pore shape of the zeolites used. The size, shape of the zeolite catalyst determines the catalytic performance in terms of both product selectivity and catalyst deactivation. In most zeolite catalyzed hydrocarbon conversion reactions, catalyst activity is lost due to carbon deposition. In this connection, the determination of the surface properties of zeolites is an important task that contributes to the disclosure of the physicochemical essence of the process of deactivation of zeolites. The recalculation of nitrogen adsorption isotherms using the t-plot model made it possible to determine the volume of micro and mesopores. Based on the t-graph data, it can be concluded that during the transformation of methanol into hydrocarbons, carbon accumulates on the surface of the zeolite. In this case, the predominant deposition of carbon on the surface of mesopores, due to the fact that in the process of decontamination, from 61 to 73% of the volume of mesopores is lost. The number of micropores also decreases, but the share of losses is 42–54%, which is 10–15% lower compared to the loss of mesopore volume.

Methanol to hydrocarbons conversion: Why dienes and monoenes contribute differently to catalyst deactivation?

2021 ◽  
pp. 134229
Author(s):  
Zhichen Shi ◽  
Sukaran S. Arora ◽  
Daniel W. Trahan ◽  
Daniel Hickman ◽  
Aditya Bhan
Keyword(s):  
Catalyst Deactivation ◽  
Methanol To Hydrocarbons

Effect of Catalyst (de)activation on Reagent Diffusion in ZSM-5/alumina Extruded Pellet for the Methanol-to-hydrocarbons Conversion

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Alexey A. Zhokh
Keyword(s):  
Catalyst Deactivation ◽  
Diffusion Rate ◽  
Micropore Volume ◽  
Coke Deposition ◽  
Alumina Catalyst ◽  
Catalyst Activation ◽  
Catalyst Pellet ◽  
Methanol To Hydrocarbons ◽  
Methanol Transport ◽  
Time Decrease

Abstract A pelletized ZSM-5/alumina catalyst was prepared by the extrusion technique. The catalyst was activated by ion-exchange with NH4NO3 aqueous solution. The activated catalyst was trained in the methanol-to-hydrocarbons reaction which caused the catalyst deactivation due to coke deposition (6.5 % wt.). Coke deposition resulted in a two-time decrease in the micropore volume. The methane, benzene, and methanol transport through ZSM-5/alumina pellet were consequently studied prior to activation, after activation, and after catalyst deactivation. A slight decrease in the diffusion rate after catalyst activation is observed. After deactivation, the diffusion rate increases insignificantly. The diffusion regime remains unchanged with respect to either activation or deactivation procedure. Contrary, for the methanol, the diffusion rate through a deactivated catalyst pellet remarkably increases due to micropore blockage by coke deposition. The obtained results reveal that the micropores blockage during the catalyst deactivation enhances the methanol mass transfer.

New insights into catalyst deactivation and product distribution of zeolites in the methanol-to-hydrocarbons (MTH) reaction with methanol and dimethyl ether feeds

2017 ◽  
Vol 7 (13) ◽  
pp. 2700-2716 ◽  
Author(s):  
Juan S. Martinez-Espin ◽  
Magnus Mortén ◽  
Ton V. W. Janssens ◽  
Stian Svelle ◽  
Pablo Beato ◽  
...  
Keyword(s):  
Dimethyl Ether ◽  
Catalyst Deactivation ◽  
Product Distribution ◽  
Zeolitic Catalyst ◽  
Methanol To Hydrocarbons

The ability of a zeolitic catalyst to dehydrate methanol to dimethyl ether affects catalyst deactivation and product distribution during the methanol-to-hydrocarbons (MTH) reaction.

The Genesis and Internal Dynamics of El Salvador's People's Revolutionary Army, 1970–1976

2014 ◽  
Vol 38 (01) ◽  
pp. 102-129
Author(s):  
ALBERTO MARTÍN ÁLVAREZ ◽  
EUDALD CORTINA ORERO
Keyword(s):  
Latin America ◽  
El Salvador ◽  
Early Years ◽  
Left Wing ◽  
Internal Dynamics ◽  
Internal Coherence ◽  
The 1960S

AbstractUsing interviews with former militants and previously unpublished documents, this article traces the genesis and internal dynamics of the Ejército Revolucionario del Pueblo (People's Revolutionary Army, ERP) in El Salvador during the early years of its existence (1970–6). This period was marked by the inability of the ERP to maintain internal coherence or any consensus on revolutionary strategy, which led to a series of splits and internal fights over control of the organisation. The evidence marshalled in this case study sheds new light on the origins of the armed Salvadorean Left and thus contributes to a wider understanding of the processes of formation and internal dynamics of armed left-wing groups that emerged from the 1960s onwards in Latin America.

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