Modern Gasworks Practice

090 MODERN GASWORKS PRACTICE was adopted on accoimt of its comparative clieapness as an enriching medium as compared with. the methods then in vogue. To-day, however, the position has been completely changed. by the world shortage of oil and, consequently, the prohibitive cost of the latter. Enrichment, moreover, has lost much of its significance owing to the introduction of calorific power standards. Accordingly, the pre-war quality of high illuminating power water gas has given way largely to tlie unenriclied or “ blue ” water gas. In some cases, where the diluent effect of the blue gas is too severe, a semi-carburetted water gas is manufactured. Enriched water gas to-day, owing to the high, price of oil, costs more to produce. than does coal gas, while with coke standing at high values it is open to question as to whether even the manufacture of unenriched gas provides, from the commercial standpoint, the most profitable outlet for coke. > The extent of the water-gas industry in this country may be gathered from the faet that approximately 24,000 million cubic feet are generated anmially, while the world’s output is in the neighbourhood of 130,000 million cubic feet per annum. The latest figures available show that the number of gasworks in the United Kingdom producing water gas is 148, of which 101 are owned by Companies, while 48 are attached to local authorities. . The benefits derived from the use of water gas as an auxiliary to coal gas may be summarized as follows :— 2. Low capital outlay per unit of capacity. Including relief holder the outlay on a carburetted water-gas plant of large capacity would amount to about one-third that entailed by a coal-gas plant of similar capacity. 3. The ground space occupied by the plant is considerably smaller than the area covered by equivalent coal-gas plant. The ratio of the areas required may, in fact, be so great as 9 to 1. As regards ground area required, Shelton gives the following figures:— Capacity of Plant. Gbound Area Required. 100 ,000 cubic feet per diem . . . .4 square feet per 1,000 cubic feet. 200 ,000 „ „ . . . . 3-5 400 ,000 „ ___________________2-75 600 ,000 „ „ . . . 2 to 2-5 7 to 10 million „ ... . 1-25 to 1-5 „ „ „ These figures include scrubbers and condensers, but not boiler house, engine room, or relief holder. 3. Sudden demands, such as those due to fog and other unforeseen contingencies, may be easily and quickly coped with. A water-gas plant may be picked up from cold in rather more than three hours. Retort benclies require three days to bring them up to working heats. 4. The expense of retort benches constantly under slow firing is obviated. 5. The quality of the gas made is easily regulated to the requirements of the moment. 6. The proportion of water gas intermixed with. the coal gas may be varied in accordance with the demand for coke. Thus, a water-gas plant possesses a con-