1 Metal Catalyse d Methanation and Steam Reforming ~~ BY J . R . H. ROSS 1 Introduction The methanation and steam reforming reactions are closely inter-related and, in general, catalysts used for one reaction will be usable, with some limi- tations, for the other. This similarity arises from the fact that both reactions occur under reducing conditions over metallic (most commonly, nickel) catalysts and, more importantly, that the types of reactive surface inter- mediate found during one reaction are also found during the other. Both reactions also suffer from the same constraints, for example, carbon deposition and susceptibility to sulphur poisoning, and hence similar approaches are adopted in both cases in attempts to overcome these constraints. The con- ditions under whch the reactions are carried out depend to a large extent o n the composition of the reactant mixture and, in the case of steam reforming, on the desired product distribution. The two reactions have another very different factor in common: there has been a considerable resurgence of commercial interesting variants of both processes. For example, although the methanation reaction has been known since the beginning of the century and it has been practiced commercially to remove traces o f carbon monoxide prior to the synthesis reactor in ammonia plants, there has recently been considerable activity on the subject of the methanation of synthesis gas; this activity has arisen because of a resurgence of interest (if only transient) in coal gasification. Prior to the increase in oil prices that sparked these renewed efforts in coal gasification, there was also an increased interest in processes and catalysts for the production of synthetic natural gas (SNG) by the steam reforming of the then cheap naphtha fractions of crude oil. These develop- ments have led to considerable research on the catalysts for these processes and also on the reactions themselves. For example, a total of 26 reviews were published on the subject of methanation in the first six months o f 1982 and this puts the subject in the top fifteen ‘research fronts’ in the physical, chemical, and earth sciences.’ Under the index terms ‘methanation’ and ‘methanation catalysts’ alone, there were approximately 200 articles listed in the 1972-1976 cumulative index of Chemical Abstracts. Under the corre- sponding headings of the 1977-1 98 1 index, there were about 650 references and there were 155 references in 1982 alone. Clearly, with such an enormous literature and with such an extensive coverage by reviews, it would be unreasonable to attempt to give a comprehensive description of all the work in the subject area embraced by the title of this review. Instead, an attempt E . Garfield, Current Contents , Physical, Chemical and Earth Sciences) 1982, 22 (No. 39), 5 D o w n l o a d e d o n 0 6 / 0 4 / 2 0 1 6 1 6 : 4 0 : 5 7 . P u b l i s h e d o n 0 1 J a n u a r y 1 9 8 5 o n h t t p : / / p u b s . r s c . o r g | d o i : 1 0 . 1 0 3 9 / 9 7 8 1 8 4 7 5 5 3 1 9 5 0 0 0 0 1
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8/17/2019 Metal Catalysed Methanation and Steam Reforming
