Modern Gasworks Practice

VERTICAL RETORTS AND CHAMBER OVENS 183 by deleting the retort altogether and substituting for it the super coke oven. The prospect, perhaps, is alluring in these days of high-priced labour, but the faet must always be borne in mind that distinet grades of coke are required to conform with the different applications to which it is put. For example, while coke-oven coke might prove ideal for the industrial consumer it would scarcely be tolerated for domestic purposes. One of th.e most notable instances of the application of coke-oven gas to town’s purposes is to be found at Sheffield. During the past few years the Sheffield Gas Company has augmented its supplies in inereasing quantities by piping gas from the Tinsley Park Colliery Company. The quantity of gas taken per annüm approxi-mates to 400 million cubic feet, and represents nearly 50 per cent, of the total gas generated in the ovens. It is interesting to note that in America the super-eoking plant is to be given a trial on an immense scale. The Carnegie Steel Company are erecting a plant which provides for twenty-four batteries of sixty-four ovens each, i.e., a total of 1,536 oyens. It has been estimated that the surplus gas from this installation, will approach. 60,000 million cubic feet per annum, or sufficient to supply a population of six millions. A. H. Middleton1 in contrasting the relative merits of producing town’s gas in ordinary retorts, or by means of coke ovens, has put forward the following advan-tages wliich, in his opinion, the coke oven presents :— (!) ■ The gas made in coke ovens is equal to, if not superior to that made in any form of retort, whilst their flexibility as gasmaking apparatus is greater than. tliat of any other type of plant. (3) The labour is less arduous and unpleasant as most of the heavy and hot work wliich used to be performed manually is now done by machinery. (4) The carbonizing costs would be reduced to about half tliose now prevailing in up-to-date undertakings working with. the systems at present in vogue in gas-works. (5) The cost of mainteaance and renewals in the retort hou.se would be reduced. (6) The coke made is of greater value where there is a market for metallurgical coke either for local use or for export. The very best foundry coke can be made in a by-product oven at the same time as a high yield of good gas, provided thai suitable coal is used. The above conclusions, though largely theoretical, are certainly deserving of the consideration of gas engineers ; but mueh. turns on the quality of the coal employed. So far as the characteristics of coke are concerned, it may be noted that the majority of coke-oven engineers ridicule the suggestion that coke ovens are incapable of yielding a domestic coke. Unfortunately, practical experience of what coke ovens can do in this respect is limited, for as yet they have existed solely for the purpose of providing for industrial requirements. General experience would mdicate, however, that mass carbonization carried out on the coke-oven scale could scarcely be expected to produce a product bearing the physical characteristics of the coke such as is obtained from the modem continuous vertical retort. 2 Gas World, Coking Supplement, Vol. LXXII, p. 9.