Journal ArticleDOI
Deactivation of supported copper metal catalysts for hydrogenation reactions
TLDR
In this paper, the deactivation of supported copper metal catalysts in hydrogenation reactions has been investigated and the best understood are Cu/ZnO formulations that have improved sulphur resistance due to formation of thermodynamically stable ZnS.Abstract:
Laboratory and industrial results are used to elucidate the general features of the deactivation of supported copper metal catalysts in hydrogenation reactions. Hydrogenations with copper catalysts are milder than with their nickel or platinum counterparts, and they have selectivities that are exploited commercially. They are used in single stream plants for production of hydrogen via the low-temperature water shift gas reaction, and for methanol manufacture from synthesis gas, and also in hydrogenation of speciality organic compounds. Common catalyst types are based on Cu/Cr 2 O 3 (copper chromite) or Cu/ZnO formulations that contain stabilisers and promoters such as alkaline earth oxides and Al 2 O 3 . These have several roles, including inhibition of sintering, and poison traps that prevent poisoning of the active metal surface. The best understood are Cu/ZnO formulations that have improved sulphur resistance due to formation of thermodynamically stable ZnS. Copper catalysts are susceptible to thermal sintering via a surface migration process and this is markedly accelerated by the presence of even traces of chloride. Care must be, therefore, taken to eliminate halides from copper catalysts during manufacture, and from the reactants during use. Operating temperatures must be restricted, usually to below 300°C when catalyst longevity is important with large catalyst volumes. Water can soften some Cu/ZnO formulations during use, and cause particle breakage that leads to high-pressure drop and maldistribution of flow through large catalyst beds and impaired performance. Commercial copper catalysts are not acidic, and since they operate under mild conditions, carbon deposition (coking) is uncommon. However, conventional site blocking poisoning with sulphur compounds, and particularly by H 2 S, is common. The initial phase involves interaction with surface hydroxyl groups and elimination of water. Sulphur is retained strongly on the catalyst, and when partially sulphided they can exhibit selectivity in hydrogenation of organic hydrogenations. A variety of other sulphur compounds, and some chlorinated organic compounds, can cause complete deactivation or enhanced selectivity.read more
Citations
More filters
Journal ArticleDOI
Production of dimethylfuran for liquid fuels from biomass-derived carbohydrates
TL;DR: This catalytic strategy for the production of 2,5-dimethylfuran from fructose (a carbohydrate obtained directly from biomass or by the isomerization of glucose) for use as a liquid transportation fuel may diminish the authors' reliance on petroleum.
Journal ArticleDOI
Challenges in the Greener Production of Formates/Formic Acid, Methanol, and DME by Heterogeneously Catalyzed CO2 Hydrogenation Processes.
A. Álvarez,Atul Bansode,Atsushi Urakawa,Anastasiya Bavykina,Tim A. Wezendonk,Michiel Makkee,Jorge Gascon,Freek Kapteijn +7 more
TL;DR: In an attempt to give an order of magnitude regarding CO2 valorization, the most important aspects of CO2 capture and green routes to produce H2 are summarized and economical aspects of the production of methanol and DME are critically assessed.
Journal ArticleDOI
Water Gas Shift Catalysis
Chandra Ratnasamy,Jon P. Wagner +1 more
TL;DR: In this paper, a review of the development of water gas shift (WGS) catalysis, especially during the last decade, is reviewed. And a critical review of WGS reaction mechanism is also presented.
Journal ArticleDOI
Progress and future challenges in controlling automotive exhaust gas emissions
TL;DR: In the early 1970s increased use of cars in some major cities had resulted in serious concerns about urban air quality caused by engine exhaust gas emissions themselves, and by the more harmful species derived from them via photochemical reactions.
Journal ArticleDOI
Review of fuel processing catalysts for hydrogen production in PEM fuel cell systems
TL;DR: In this article, the advances achieved during the past few years in the development of catalytic materials for hydrogen generation through fuel reforming, 1 water-gas shift and carbon monoxide preferential oxidation, as used or aimed to be of use in fuel processing for PEM fuel cell systems.
References
More filters
Book
Heterogeneous catalysis in industrial practice
TL;DR: In this article, the use of solid catalysts and catalytic reactions in large-scale industrial operations is discussed in terms of chemistry, kinetics and engineering of heterogeneous catalysis, listing applications to procedures and processes in the lab, pilot plant and commercial setting.
Journal ArticleDOI
Synthesis of Methanol
Journal ArticleDOI
The activity and state of the copper surface in methanol synthesis catalysts
TL;DR: A frontal chromatographic version of this technique has been developed which is very suitable for in situ measurements and this has enabled the apparent copper areas of various catalysts to be measured after exposures to methanol synthesis gases of different compositions at typical industrial conditions in microreactors commonly used for assessing the methenol synthesis activity of such catalysts as discussed by the authors.
Journal ArticleDOI
Novel mechanism for the formation of chemisorption phases: the (2×1)O-Cu(110) added-row reconstruction
TL;DR: In this article, a two-dimensional precipitation from a dilute mixed fluid into a solid phase rather than a solid-solid transformation is described, which is more appropriately described to be of ''added-row'' rather than of ''missing-row''.
Journal ArticleDOI
Properties of Copper Chromite Catalysts in Hydrogenation Reactions
TL;DR: In this article, a 4-h reduction under H2 at 573 K compared to either 473 or 673 K, gave the highest specific activity for furfural and crotonaldehyde hydrogenation over an unpromoted copper chromite catalyst.