COAL RESEARCH

Evening Star, Issue 20136, 28 March 1929, Page 10

COAL RESEARCH

PROGRESS SH BRITAIN FUEL FOR SHIPS “ So I'iir as Great Britain is coneeniec], pulverised Incl *s still in infancy. although marked progress lias taken place during; tile last lew years,' said Dr 0. H. Lander, director of hied research of the Department of Scientific and Industrial Research, speaking at the Royal Society of Aits, in Loudon recently. Dr Lander's remarks that ‘‘ the application of pulverised luol to marine purposes is exceedingly attractive in a countrv which has no indigenous supplies of natural oil,” are lull of truth, and this fact will result in increased effort being made to develop the possibilities ot using powdered coal more extensively for marine purposes. He added; “The combustion of solid material must always suffer from the dis- j ability that, uidike even the heaviest I oil particle, it cannot be vapourised 1 immediately, but it can still bc_ brought by pulverisation into a state in winch tiro surface exposed to the action of air is enormously increased over that of the lump, or even of the slack, lorm; _al- i though, even with the finest pulverisation attainable, the particles still re- j main large compared with chemical: molecules. It is only with the simplest molecules, such as carbon monoxide or , hydrogen that more admixture with air j is sufficient to ensure complete combustion immediately the temperature is . raised to the ignition point. With more complex molecules relative motion be- ’ comes necessary so that they may come I successively' into contact with the recpiircd number of oxygen molecules. | This explains the developments which have taken place in the manner of : burning powdered coal, and affords a, J reason for the success of the so-called, turbulent burner. Turbulence is, , however, an uncontrolled way of attain- j ing relative motion between coal ami ; air particles, and involves a breaking I np of stream lines. What is needed rather is to obtain as stable and stream line a form of motion of the air ns possible, and induce the particles of combustible to move from one stream line to another, in as controlled a manner as possible. During recent years burners and furnaces—for the latter are equally important have gradually tended towards better ori this relative motion, but mathematical analysis of the problem shows that much more is possible .and that the limit to the amount of heat release which can be obtained in a furnace of given volume is limited only by the impossibility of obtaining furnace materials which will stand the drastic action to which j they may bo subjected.’' COAL A HOME PRODUCT. Discussing the subject of pulverised | coal and its use for marine purposes, Dr Lander made the comment referred to earlier in this article. The ap- k

plication ot pulverised coal io marine purposes,” he said, “is exceed!ngl.v attractive in a country which has no indigenous supplies of natiinil oil. J lie full advantages of oil firing are not likely to bo obtained by pulverised coal, but it is extremely likely that many of them could he realised. The first successful pulverised coal ocean-going steamer was the Mercer, belonging to the United States Shipping Board. At the present time the Shipping Board is investigating a very attractive form of pulveriser in which, instead of there being one pulverising mill for one, two, or even three boilers, a small complete installation of pulveriser, fan, and burner is fitted to each furnace of a Scotch boiler. I had the opportunity of inspecting this test installation at the Philadelphia test navy yard in November last, and was impressed with the simplicity of the apparatus and tho excellent results which were being obtained. It is understood that Hie vShipping Board arc at the present time fitting a vessel which will be tired this type of equipment entirely.” In connection with the exceedingly useful work which is being carried out in Great Britain in various directions, Dr Lander referred to the experiments on the Stuartstar with unit equipments of the Woodeson type as being especially interesting. Experiments in other directions were also being made. A new ship being built by the Borwinclmoor Shipping ' Company, is being equipped to bum pulverised fuel, and half the boilers of the New Zealand Shipping Company’s vessel. Horornta, are being tried out with the Howdeu Buell system. He stated: “In some of the earlier experimental work carried out during the war, auxiliary combustion chambers were built outside the boiler. The present method, which is likely to render pulverised fuel for marine use commercially practicable, is entirely due to the development of burners in which the indication of turbulence the long flames previously associated with pulverised fuel combustion have been considerably shortened.’!