February 6,; 1914 ______________________________________________________________________ ____________________________ 302 THE COLLIERY GUARDIAN. Table I.—Results of Tests of a 500-Horse Power Gas Engine at the Talk-ct’-tA’-Hill Colliery, May 23, 1912. Details. Overload. Full load. Three-quarter load. > Half load. Volts ■) Amperes > switchboard Kilowatts J Volts S Amperes > exciter Kilowatts ) Total kilowatts ,, brake-horse-power Time of test Duration Gas used „ ,, per hour „' „ „ at standard temperature and pressure Gas temperature „ pressure, in inches ,, used per brake-horse-power-hour ,, used per kilowatt-hour Calorimeter:— Higher value Lower ,, British thermal units per brake horse- power hour British thermal units per kilowatt-hour... Brake horse-power thermal efficiency Water used per hour, in gallons Height in V notch, in inches Gallons used per brake horse-power hour ,, „ kilowatt-hour Inlet temperature of water Outlet ,, „ Temperature from bottom cylinder „ ,, total cover ... Oil pressure, in pounds per square inch ... Water „ „ „ „ ... Revolutions per minute Barometer, in inches 405 f 440 4 14*7 C 6*5 411’5 590 4.18 to 6.22 2 hrs. 4 min. 29,450 14,250 13,437 20 degs. Cent. 2’85 22’8 32’6 483 433 9,829 14,115 25’9 4,800 41 8T5 11’7 62 degs. Fahr. 114 „ 94 „ 93 ,, ,, 18’4 17’4 300 28’75 364 440 14’3 6’25 370’25 530 12.0 to 3.30 31 hours. 45,000 12,850 12,214 18’2 degs. Cent. 3 125 23 33 468 420’46 9,6H4 13,865 26’4 2,850 3’65 5’4 7’7 55’3 degs. Fahr. 133’2 „ 111-3 „ 103’9 „ 18 21T 3<0 28’75 265 440 13’6 6 271 393 6.30 to 7.30 1 hour. 10,300 10,300 9,712 20 degs. Cent. 3’5 24’7 35’5 550 503 12,424 18,000 20 5 3,400 3’9 8’65 12’5 65’2 degs. Fahr. 119 „ 94’3 „ 94’7 „ „ 19’4 21’2 300 28’75 190 440 12’5 5’5 195’5 286 7.55 to 8.55 1 hour. 7,450 7,450 7,048 19’3 degs. Cent. 4T25 24’6 36 525 (mean, 500) 478’5 (mean, 458’8) 11,770 17,200 21’6 3,100 3’75 10’82 15’8 65’7 degs. Fahr. 114’6 „ 98 „ 92’3 „ 19’6 21’6 300 28’75 would give less than 40 per cent, of ash, and, while using up all the waste, would evaporate all the water required. This point being reached, an analysis of the figures, made upon a basis suggested by the purchasers, showed the excellent results recorded in Table III.:— Table III.—Estimated Annual Working Costs of a Mond Gas Plant with Ammonia Recovery, Sup- plying Gas to Evaporate 126,000 lb. of Water per Hour when Gasifying a Mixture of Colliery Waste and Burgie Coal, Working at full Load for 168 HOURS PER WEEK AND 52 WEEKS PER YEAR. Fuel: £ S. d. 67,300 tons of burgie at 6s. 9d. per ton ... 22,863 15 0 ......... 49,500 tons of colliery waste, free........... — Labour (details below)....................... 4,298 0 0 Repairs ...................................................................... 2,200 0 0......... ..................... Stores, &c......................................_____ 800 0 0 Establishment charges ............................ 470 0 0 * 30,631 15 0 Acid : 3,860 tons at 35s. per ton ............. 6,930 0 0 Bags and packing sulphate ................. 1,320 0 0 38,881 15 0 Credit 3,960 tons of sulphate at <£10 per ton ... 39,600 0 0 Credit balance...................... 718 5 0 Depreciation on £50,000 at 7| per cent_______ 3,750 0 0 Total loss .......................... 3,031 15 0 Present practice, 48,000 tons of coal at 6s. 9d. per ton................................. 16,200 0 0... Labour at Is. per ton....................... 2,400 0 0 Total ............................. 18,600 0 0 Deduct loss ........................ 3,031 15 0 Net profit........................................................... 15,568 5 0 Add tar, 2,500 tons at 12s. per ton ............. 1,500 0 0 Total profit ............................ 17,068 5 0 Fig. 4.—Section of National Gas Engine £liHI At the present price of sulphate (over <£12 10s. per ton) the profit would be increased by an additional <£10,000 per year. At the commencement, the gas was used for boiler- firing, but at present they have three 500-horse power Korting engines (made by Messrs. Mather and Platt), and have also on order two of their Duplex engines, each of 1,000-horse power. It is proposed to supersede gradually steam-driving by gas-generated electricity. This will probably reduce the fuel consumption for works purposes to a quarter of what it now is : then three-quarters of the gas generated will be available for further electric-current generation, say 12,000 kilowatts available for sale for local lighting or power under the same control. This would, even taking the value of electricity at Jd. per unit, greatly increase the profits from the gas plant. Although this extension is, how- ever, only in the air, it is mentioned to show the great advantages that can be gained by using this class of plant. As an example of a smaller installation, the writer would like to mention one which the National Gas Engine Company, in conjunction with the Power Gas Corporation, have installed for the Accrington Corpora- tion. This is of 2.500-horse power, and at present two 1,000-horse power National engines and alternators are being run from it, and an extension of double this size is now in hand. The fuel consumption averages 152 lb. of coal per kilowatt generated, and the total oil used is 35 gallons per week on the gas-plant auxiliaries and gas engines, the sulphate of ammonia recovered being above 901b. to the ton of coal. This is not a mere test result, but what is being done in actual practice to-day, with an output of 130,000 units per week. A plant of this description certainly takes up a fair amount of room, but is nothing like so complicated as it looks, the bulk of the work being plain pipe work, and these only for pressures of 2 lb. or 31b. As showing the adaptability of this class of plant, the writer might mention that at the National Gas Engine Company’s works, where there is a plant of similar size, one of the 1,000-horse power producers was shut down for two months, and within half-an-hour of the attendant being notified that the power was required, it was working to its full capacity, the coal used in the two months’ stand-by being only 38 cwt. There are,however, installations where, owing to the small size of the plant, it would not be advisable to instal a recovery plant, on account of the high capital costs, but the non-recovery would still show an advantage over boiler plant. At the Littleton collieries a 700-horse power plant (fig. 2), made by the Horsehay Company, has been at work since 1910. This plant has been driving two Westinghouse engines, each of 350-horse power, and an extension, consisting of a duplicate producer and a 600-thorse power National gas engine, has just been installed. The coal consumption has been about 1 lb. per brake horse-power hour, and the tar recovered would be about 1 cwt. to the ton of coal burnt. In the 700-horse power plant, one man has been sufficient for unloading the coal and. looking after the producer. Among the advantages to be gained by this type of plant are the low fuel consumption; the ability to use different classes of' low-grade coal; small water con- sumption for the producer ; and the cleaning of the gas. The washer can be worked entirely on tar as a cleaning medium, and, when this is done, no added water for cooling or cleansing is ever brought into contact with the gas: the result of this is that it is subject to a condensing operation throughout, no extra water being evaporated which requires to be subsequently thrown down by water fans or further cooling surfaces, and as a consequence the tar effluent from the plant contains less water, and so commands a higher price. The paper concludes with a brief description of some suitable types of engines. _____________________________ The annual general meeting of the Geological Society will be held on Friday, February 20, 1914, at 3 p.m. After the meeting, the Fellows and their friends will dine together at the Hotel Cecil, Strand, W.C., at 6.15 for 6.30 p.m.