STEAM FROM PETROLEUM.

Globe, Volume XX, Issue 1529, 11 January 1879, Page 3

STEAM FROM PETROLEUM.

Scientific American,”]

Tho theoretic calorific power of ordinary petroleum is about 16, of anthracite coa] i 3 of bituminous coal 15 ; that, is to say, a pound i of petroleum, with perfect combustion, will raise 16,000ibs of water 1 deg. Fab., a pound of anthracite coal 13,0001bs water 1 deg,, etc., bat the heating effects depend so largely upon the method of combustion that, in ordinary practice, these theoretic values are but little considered, the estimation in which they are hold as working agents being determined by the practical economics resulting from their use. The extreme wastefulness of tho methods of using coals has long exercised ingenious and scientific minds in endeavors tv) find some remedy ; but the best results thus far obtained by the improved Siemens and Ponsard gas furnaces and the pulverised fuel process show a utilization of but 20 to 25 per cent, of flic total heat of the fuel—a great gain certainly over the 7 to 8 per cent, utilization in the ordinary reverberatory furnace, but still far short of the object aimed at. On the discovery of petroleum in America the attention of metallurgists was at once directed to it in tho hope of finding a fuel possessing important advantages over coal, and in every direction methods were devised for its application for metallurgic purposes; but its constitution and character were so little understood, so little known of the peculiar treatment demanded for tho development of its Dowers as a fuel, (hat most of tho proposed xnethQds proved worthless. After tho elimination of the majority of these, severe! remained which possessed,”in a greater or less degree, certain points of value. It had been determined, for instance, that tho oil should be reduced to a fine spray or atomised, as it is called; that a jet of steam impinging upon a drip of the oil and conveying it into tho furnace was tho most effectual agent for this purpose ; and that an exceedingly large amount of air was required to combine with the gages to insure complete combustion.

These points were thought to cover all Iho requirements, and various styles of apparatus were designed to carry them into effect, and were experimented with in various places, Tho resists of some of the most favorable working*, as reported by Boards of Nava] lOnginccas, eiirywed economies of from .‘!8 to (.58 per cent, over th v u?o of anthracite coal in Bie generation of steam, und j-hp further advantages of great reduction in vmgni end bulk of tho fuel, in labor of firing, and in quick attii-ju.WOut of high tempcraturcc,

I As might bo expected, however, of these early attempts, the apparatus was, in all cases, imperfect, the conditions necessary to complc'c combust!)a not yet understood, nor the dangerous character of the fuel fully provided against; therefore, notwithstanding the economies shown, the incomplete combustion with its accompanying offence, the difficulty or controlling Dm temperatures, and the occasion!.! explosions and tires which alarmed bot h owners and insurance companies, led, on all sides, to the temporary abandonment of the new fuel. Further mew ligations, however, here, as well in England and France, determined that the steam jot as used, though apparently indispensable fm- atomising or scattering the oil ioto spray, greatly interfered with its combustion by abstracting beat from the flame, and that, to be effective, to permit perfect combustion, it should bo superheated to so high a degree that it would vaporise the oil on contact. The amount of air required for smokeless combustion —52 volumes to 1 of petroleum vapor —and the fact that they should be thoroughly mingled, were also ascertained. Within the past few years so good an account has been made of this knowledge that tdi indications s'rongly point to the general substitution, in no very distant future, of petroleum for coal in the manufacture of glass, of iron, steel, and other metals, and for the forma* ion o : : steam. Prolonged workings in puddling and heating furnaces have demonstrated that by its use double the number of heats, as compared with coal result?, can readily bo obtained in a given time and with an economy of full 50 per cent, with coal at sdo!s. per ton and oil at lOdols. per barrel. In crucible furnaces, wherein a higher temperature is required and less of the calorific value of coal is utilized than in any other metallurgic operations, the advantages of Die new fuel, as demonstrated in Pittsburg in the manufacture of steel for the E.vt River bridge, are still more decided. Under boilers an average evaporation of 1P93 pounds of water from 212 deg. Fah. has been obtained from one pound of the oil, which had a theoretic efficiency of 17'5 ; and another instance is given of an evaporation of 16 77 pounds of water from 212 deg. by a pound of oil, 17 52 theoretic value. The great disparity between the practical effect s of oil and coal—so much in excess of the difference in their calorific powers—is explained by the wasteful consumption of the solid coal, as above noted; while the combustion of the oil is very nearly or quite perfect, and is completed within the furnace, thus securing for the work from 85 to 90 per cent, of its total heat. The intensity of the oil flame, too, is a most important factor in the economy, assuring a temperature of nearly 3500 deg. Fah., in a properly-constructed furnace. This heat and the exceptions! purity of the flame—there being no residual ashes or sulphurous gases—also insure purer iron in the puddling and melting, and better welding in the heating furnace, and they present unusual advantages to workers of glass. The dangers ordinarily attending the use of this now fuel have boon overcome, in one instance at least, by an ingenious and simple device that has been approved by those underwriters who have had it brought to their notice, thus removing an objection which lias operated seriously against the earlier adoption of the process. Coal tar and the residuum of petroleum are also utilized in this manner by liquefying them by heat or mixture with the oil, so that they will flow readily, but Dio residuum of ashes from their combustion is objectionable in some cases. Coal oils also are capable of being used with good results by this method, hut the supply of petroleum will not, for a long while at least, be likely to become so limited, or its price so high that economy will require any of these substitutes. It is not, by any means, to be supposed that science arid ingenuity have been exhausted iu bringing the petroleum fuel process to its present strong position ; it is yet in its infancy, and, as attention ia drawn to it, will be improved in many respects. Because of its youth and Die little experience with it, and its former unsatisfactory performance, it has been slighted by manufacturers; and because it will revolutionize the present methods of furnace firing, it will for a considerable time be successfully opposed by the workmen, who like not to be forced out of their well-worn ruts, and who usually control such matters in Die majority of iron works. There are many rival inventors in this field striving to pass one another in the race, but most of them seem to be almost hopelessly out with their crude and unpractical appliances and ideas ; and to this class, judging from inspection of the furnace, etc., at the Brooklyn Navy Yard, and from general observation, belongs, in our esteem, their designer. Quito recently the inventor of perhaps the most perfect gy stem for using this fuel has applied it to the manufacture of polished sheet iron, with results superior to any before attained in this count ry. It would bo difficult, wo think, to name any process which, even at its present stage of development, is more worthy of the attention of all those manufacturers to whom cheaper fuel is a matter of any importance.