USE OF PULVERISED COAL

Taranaki Daily News, 9 June 1930, Page 13

USE OF PULVERISED COAL

BOILERS OF THE HORORATA. ECONOMY’ OF NEW SCHEME. Five of the six boilers of the New Zealand Shipping Company’s steamer, the Hororata, which arrived at New Plymouth on Saturday, have been equipped to burn powdered coal on the HowdenBuell system. The steamer, which is to load dairy produce and meat, is from London, via Suva and southern ports and is of 11,200 tons provided with twin-screw, quadruple-expansion . engines. The boilers are of the singleended, Scottish type. The Hororata was built on the Clyde by William Denny and Brothers, Ltd., in 1014. Towards the end of 1928 three of her boilers, were fitted •with IlowdenBnell - equipment, and since, that time she has covered 70-000 niiles: with great success. The first three boilers were equipped by. R. and 11. <•?;•<?<•• i! . Silley Weir, Ltd., who recently completed the new installation. In addition to fitting two more boilers with powdered coal burners, five coal pulverisers of the firm’s, new ring and roller type have been installed, which are driven through clutches by a compound steam. engine. It is interesting to note that these five pulverisers take up only the same space as the three originally installed. In accordance wtith Board of Trade' requirements, hand-fir-ing has been retained on one boilwhich will serve as a donkey boiler and emergency unit. The. nhw fuel mill require* nine to ten' brake horse-power to drive it, or from bne-fotn th T to one-fifth the power needed, say, two years ago for driving the pulverising mills them used. An iny portant feature; of, . fhe ■ installation ./is. the four-way fuel distributor in which there are no working parts, the coal stream being divided by a sei of adjustable guide blades, while hinged flap valves are arranged, enabling any burner to be isolated from the system. The burners are very simple in design. High temperature air from heaters on the boiler fronts is introduced into the stream of primary air carrying the fuel •n such a way as to give a rotary motion with an intimate mixture. of air. and fuel, and a short flame. _ With the exception of one or two electric motors used for driving the screening plant,’ steam engines and small steam turbines , are used for- the pulverising mills and fans. If the prices for coal were taken into account it was estimated that the use of pulverised coal would mean a saving of about £5OOO a year on the working costs of the ship, said Mi. J. Silley, chairman of R. ahd H. Green and Silley Weir, Ltd., when speaking at a luncheon on board the Hororata hi London. There was also a smaller wages bill, as the number of stokers w*as reduced by twelve men. With regard to new ships, Mr. Silley expressed the opinion that the time had now arrived when pulverised coal burning ships could be built and engined at the same price as an ordinary tramp steamer with hand-fired-boilers. He was prepared to offer plants for ships of, say, 9000 and 10,000 tons, with engines of 20'00 to 3000 horse-power, which would not involve the ship-owner in additional costs, and would enable him to take full advantage of the big economies offered by pulverised coal.