Modern Gasworks Practice

WATER GAS 751 when compared with. the water-gas systems in conamon use in this country. It will easily be grasped, however, by tabulating the working as follows:— Oil sprayed in (say) No. 1. generator ...... 3 minutes. Steam blown through spray ....... 75 seconds. No. 1 “ dipper ” valve closed and No. 2 “ dipper ” opened. Steam admitted under firebars of No. 1 .1 minute. Air admitted to No. 1...............................about 10 seconds. Total period of “ run ” about 6 minutes. After the completion of the above “ run,” the blowing cycle, as previously de-scribed, commences, and continues for about two minutes. The “ run ” is then resumed, but with. the difference that the first generator in the preceding cycle now becomes second in the sequence. This alternate operation of the generators causes practically similar working conditions for both vessels as regards temperature and consumption of coke and oil. THE INDUSTRIAL USES OF WATER GAS In addition to being used as an auxiliary to coal gas, “ blue ” water gas has with.-in recent years been applied, with. very satisfactory results, to the welding of plates and heating of fumaces and forges. This metliod has proved of great practical advantage in welding tubes for gas, water and steam mains, for boiler work and also for melting steel. Tests conducted by the Admiralty show the strength of. a “ blue ” gas weid to be equal to that of the plate. Ha ving a very mach higher calorific power than producer or suction gas, “ blue ” water gas may be used for driving gas-engines, the consumption being about 35 cubic feet per B.H.P. hour. The con-sumption of ordinary suction gas is about 80 cubic feet per B.H.P. hour. No water gas, liowever, is entirely satisfactory when used for power, for the large proportion of hydrogen prevents high compression in the cylinder of the engine. By far the most important property of “ blue ’’ gas is its exceedingly high, flame temperature. Dr. Roessier has found that by admixture with heated air a temperature considerably above the melting point of platinum may be easily obtained. Under general conditions, however, the temperature of the hottest part of the flame is about 1,500° to 1,600° C. It is owing to this property that “ blue ” gas is applicable to such processes as welding and forging, and for use in fumaces. In all processes of the above kind there is no necessity to purify the gas from sulphuretted hydrogen—merely an ordinary water-scrubber is used. It is, in faet, an advantage to leave the gas unpurified, for it then has a distinet smell, and any escape may be quickly perceived. Thus one of the greatest drawbacks to “ blue ” gas—its freedom from smell—is more or less overcome. In Germany it has in some cases been thought advisable to impart a distinet odour to the gas, by passing it through a heavy hydrocarbon oil, such as mercaptan. A process for which. water gas may be employed, and one which. will probably be largely developed in the future, is that of producing hydrogen. Cement manufacturers are now making use of water gas, ■which is introduced