摘要:

A broad range of hydrocarbons and oxygenated products can be synthesized catalytically from CO and H2produced by the gasification of coal, Since the earliest examples of such chemistry were reported by Fischer and Tropsch [1, 2] in 1926, the nonselective generation of organic compounds via the hydrogenation of CO has become known as Fischer-Tropsch synthesis. In the intervening 54 years, many efforts have been made to identify the mechanism by which reactants are converted to products. These studies have been motivated in large measure by the desire to understand how catalyst composition and reaction conditions govern the distribution of products formed. A brief review of the mechanistic hypotheses developed prior to 1970 will be presented here to serve as background for a discussion of more recent ideas, Details concerning the earlier studies can be found in a number of reviews [3–15] published previously.

ISSN:0161-4940    

DOI:10.1080/03602458108068076

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Continuously increasing oil prices, a dwindling supply of indigenous petroleum, and the existence of extensive coal reserves has made the conversion of coal to chemicals and clean-burning fuels an increasingly important part of the national energy programs for a number of industrial nations. In particular, there is a growing interest in the production and use of synthesis gas as a feedstock for the manufacture of fuels and chemicals. Most of the proposed routes are catalytic in nature, and are directed at overcoming the limitations of Fischer-Tropsch chemistry, especially selectivity. Over the past several years, research efforts have led to new selective routes to various fuel fractions; to petrochemical feedstocks including light olefins and various aromatics; to commodity chemicals such as ethylene glycol, ethanol, and acetic acid; and to a number of other fuels and chemicals.

ISSN:0161-4940    

DOI:10.1080/03602458108068077

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Sasol One, formerly known as South African Coal, Oil, and Gas Corp., operates a plant for the production of liquid fuels, pipeline gas, and chemical products from coal in Sasolburg in the province of the Orange Free State in South Africa. This plant started production in 1955 and today Sasol has 25 years' practical experience with the production of synthesis gas via Lurgi coal gasification and the synthesis of hydrocarbons by the Fischer-Tropsch process. In 1975 the decision was taken to build a much larger Fischer-Tropsch plant, mainly for the production of motor fuels, and this plant is at present being commissioned. The first final products from this plant will become available to the public early in the second half of 1980. The continuing increase in crude oil prices and instability on the oil supply market were the incentives for the decision in 1979 to build anther Sasol plant practically identical to Sasol Two. Construction on this Sasol Three plant is well under way and it is expected to start producing in 1982. The three plants together will bring South Africa significantly closer to its goal of independence from foreign crude oil supplies.

ISSN:0161-4940    

DOI:10.1080/03602458108068078

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

With his discovery of stilbite in 1756, Cronstedt [1] recognized the existence of a new group of minerals consisting of hydrated “aluminosilicates” of the alkali and alkaline earth cations. While several members of the group may have similar or nearly identical compositions, each possesses its own, unique crystal structure. At present there are 35 known naturally occurring zeolites. The crystal structures have been determined for 27 and all but about 10 have been prepared synthetically. This paper will present the definition of zeolites and focus on the synthesis and physicochemical properties of two catalytically and commercially important synthetic zeolites, zeolite Y and zeolite ZSM-5.

ISSN:0161-4940    

DOI:10.1080/03602458108068079

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

In recent years molecular sieve catalysts have assumed an increasingly important role in industrial catalysis, Applications of zeolite catalysts are expanding from the traditional petroleum refining to new and improved fuel processing applications, and to new roles in both the petrochemical and chemical industries. Up to the present, all commercial applications of zeolite catalysts have been carried out with aciaic zeolites. Recent investigations of zeolite chemistry revealed several important features which appear common to both alkali and acidic zeolites. This new chemical evidence raises the possibility that the underlying physicochemical features of both types of zeolites play a role in catalysis.

ISSN:0161-4940    

DOI:10.1080/03602458108068080

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Zeolites have been used as catalysts in industry since the early 1960s. The great majority of commercial applications employ one of three zeolite types: zeolite Y (faujasite); mordenite; ZSM-5. By far the largest use of zeolites is in catalytic cracking, and to a lesser extent in hydrocracking. Table 1 presents some data showing the commercial importance of this field [1]. The data are for United States refineries only and must be multiplied by a factor to arrive at worldwide use. Better than 90% of free-world cracking units now use zeolite catalysts. For many years it had been assumed that crystalline aluminosilicates with their uniform pore structure would make inferior catalysts to amorphous silica-slumina with a rather wide pore size distribution. The tremendous acid activity of hydrogen zeolites also was not recognized. Rabo and co-workers [2] showed at the 2nd International Congress on Catalysis that hydrogen exchanged faujasites possessed good isomerization ability, but commercial application in catalytic cracking became feasible only after Plank and Rosinsky at Socony-Mobil Oil Co. succeeded in stabilizing zeolite Y against steam and heat sintering by exchange with rare earth ions and by separating zeolite crystallites by incorporating them into a silica-alumina matrix which provided a heat reservoir along with some synergistic cracking effects. Modern cracking catalysts comprise 10–40% rare earth exchanged H-Y zeolite dispersed in a matrix of silica-alumina, semisynthetic clay, or natural clay.

ISSN:0161-4940    

DOI:10.1080/03602458108068081

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0161-4940    

DOI:10.1080/03602458108068065

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor