Gas v. Steam Power Plants.

Progress, Volume I, Issue 8, 1 June 1906, Page 210

Gas v. Steam Power Plants.

Mr. Charles Enth, of Enth's Engineering Company (Limited), writes to Engineering as follows — I notice in your Glasgow letter, page 61 of your issue of the 21st, it is stated that the coal consumption of prcducer-gas engines is less than 1 lb. per brake horse power and that the waste gases may be utilised for steam boilers. I submit that it is quite impracticable to utilise such wast? gases as the result of all the complications involved would not add more than, say, 2 per cent, to the power developed. In producer-gas plants fully 25 per cent, of the heat m the coal is lost m the gas producer ; of the remaining 75 per cent, about 25 per cent, is absorbed 111 the water used for cooling the cylinders ; and 25 per cent, is claimed to be

utilised in the production of power, leaving onb 25 per cent in the exhaust gases. Therefore it a ton of suitable coal will develop 2 500 h r in gas engines and if the exhaust gases represen one quarter of a ton, the steam boilers might absorl at most one-half of such heat ; so that the hea available m boilers from exhaust gases from 2 qo< b.h.p. gas engines is equal to the heat from 'thi direct combustion of 2* cwt. coal, which woulc develop, say, 50 b.h.p. only, or 2 per cent mor power. Any engineer will agree that this -> pc cent extra power will not justify the complication involved in the attempt to utilise such exhaus gases. The same fallacy characterises Mr Stott' paper noticed in column 2 of page 60 of the sam, issue, for Mr. Stott assumes thlt a consideraS proportion of the waste heat of a producer-^ plant can be utilised for raising steam. Mr. Stot manages a large Amen can steam plant, but hi advocacy of gas-powe plants is evidently baset on theory alone. Thi thermal efficiency of ga engines may be mon than double that of stean engines or turbines, bu the cost of the fuel usec m gas plants "eneralh far exceeds the cost pc" ton for the fuel used 11 steam plants, and thi depreciation on the ga plant is much heavier and the fuel cost is onh from one- third to one-hal of the total cost of gener ating electric power, and so far, there is no evidence to indicate that producer gas plant can ccmpet< with steam plant m thi generation of electricity Regarding the para graph m your Electnca Notes, on page abou coal-dust firing for stean boilers, it may be men tioned that as the smalles coal can be and is smoke lessly burnt on gratelesmechanical stokers witl the highest efficiency there is no occasion to gc to the expense of is. pei ton for grinding it te powder and spraying 11 into boiler furnaces.

When a man has fame he does not know it.