OIL INVASION

Evening Star, Issue 19762, 12 January 1928, Page 13

OIL INVASION

INDUSTRIAL FUEL GREAT CONVENIENCES COAL’S GREAT RIVAL. There are to-day very few departments of industry in which fuel is required for power or heating purposes that have successfully resisted the invasion of oil. The record of this type of fuel is one of increasing expansion, of the discovery and exploitation of enormous supplies of the natural product, and of the numerous appliances specially designed in order to utilise the liquid to the greatest advantage. The growth of the oil industry is sufficiently evidenced by the remarkable fact that over 650,000,000 barrels were raised in 1920, some sixty years after the first drilling operations by Drake m Pennsylvania. As a complex of many different compounds, mostly alike in chemical characteristics, the natural liquid was soon treated to yield different portions having different spheres of usefulness, states a writer in the London ‘ Daily Telegraph.’ The very light portions provided the fuel for the type of internal combustion engine so largely in demand for comparatively light transport. A heavier distillate supplied the need for an oil which could be efficiently and safely burned as an illuminant. The heavier fractions then disclosed the possibility of further fractionation, to enable them to serve as materials either for lubrication or for internal combustion engines of the more massive type, while oil early came into extended use for the firing of boilers for steam-raising purposes on land or in the Mercantile Marine. The story of the conversion of 'many coal-fired boilers to the use of oil fuel is too recent and-too well known to need more than passing mention. With their somewhat uniform thermal values those oils which were competing with coal and coke seemed at first at a financial disadvantage, but the history of their progress is a sufficient answer to the suggestion that comparisons should be based only on the cost of the thermal units contained in the fuels. While the cost of the thermal units of oil considerably exceeds that of those in coal, the remarkable supersession of coal by oil suffices to indicate that other important factors come prominently into play. Briefly, these may be described as flexibility of the combustion process, control of the temperature, thermal efficiency for most, if not all, purposes, adaptation to use with preheated air, cleanliness of combustion, and the possibility of recovering the heat from the waste gases. METALLURGICAL FURNACES. While the larger applications, such as the use of oil fuel on liners, have possibly claimed greater attention, not only from the layman, but also from furnace, users long accustomed to the use of coal and coal products, there are at the present time numerous examples of furnace-firing in which these heavy oils have no less successfully replaced the older fuels. Many of these are to be found in metallurgical furnaces. Numerous are the operations in the treatment of metals which call for heating and reheating, sometimes with great frequency, and for these, as also for other industrial operations, oils have had a long run of undisputed success. In spite of the higher first cost of the thermal units of the oil, the expense has been reduced in comparison with coal used under similar conditions. There has, too, been an increase in the output of furnaces when oil-fired, while more uniform conditions, the value of which is becoming more and more appreciated, are readily assured. Again, oil-fired furnaces can be started up and shut down more rapidly with little or no waste of fuel. Evidence also goes to show that the use of oil : prolongs the life of crucibles, an item of cost of no small importance in metal-melting operations. The cumulative effect of these advantages at once supplies the reason for the extending use of oil for this class of operation. The attainment of high temperatures exceeding those possible with solid fuels is another factor that cannot be overlooked. These arise from the fact that oil when injected into a furnace is volatilised, and subsequently as a gas, may be economically burned with a much diminished supply of air, the result being a reduction of waste gas and the loss of heat occasioned by its high temperature. A still further advantage is the fact that preheated air supply, easily procurable, adds to the ture of combustion, and loss of heat due to this increased temperature in the gases is again avoided by the application of the regenerative or recuperative principle originally applied in early types of steel furnaces run on gaseous fuel. Altogether, the advantages of oil firing are too obvious to need detailed comment.

Two advantages of oil for metal melting ar© at once apparent. These are the rapid attainment of the desired temperature and the greater fluidity obtained at the higher temperature. The melting of brass provides a common example. This is accomplished either in an ordinary crucible furnace, or, more conveniently, in a tilting type of furnace. Nowadays the fuel consumption has been reduced well below what it originally was. Experience goes to show that approximately one gallon of oil is required to melt 1001 b of the metal. _ With coke some 251 b is required with ordinary draught, while the amount may be reduced to 171 b or 181 b with forced draught. As prevailing prices the comparison may seem to be advantageous to coke, but many other factors have also to be taken into account. With oil as the fuel the consumptions for copper melting fire set at 17.5 per cent., while with grey castiron the figure is up to 25 per cent. Another metal largely melted by oil is aluminium, and here the oil required is of the order of one and a-quarter gallons per hundredweight of metal. The increased output of the furnaces owing to the greater rapidity of tho operation, coupled with the increased number of limits which can be worked with the same crucibles, are determining factors in the operation, and hero d is authoritatively stated that the fifty melts common with solid fuel can bo increased to sixty to seventy with oil. Where larger reverberatory furnaces are used the consumption of fuel may bo considerably reduced, especially when tho waste gases are utilised for pre-heating the air to be used for the combustion process. CLASS FURNACES. The successes recorded in tho case of metal melting may well suggest to many engaged in thermal operations the question whether oil firing would not provide equal advantages for them. An important _ lead has already been given in this direction in the numerous applications which have so far been made with conspicuous success. These include the _ heating of galvanising tanks, the firing of glass furnaces, furnaces for bolt and nut making and rivet heating, forging furnaces, billet heating, cloth singeing prior to bleach-ing-and dyeing, And bottle making. A number of these operations are out of the usual run of heating. In some cases they require high temperatures and rapid heating. The heating or glass furnaces provides one instance. Special interest attaches to the type of burner and its disposition; but tanks of large capacity are the order of the day in an Indus-, try which has since the war had a considerable expansion in this country. Quick melting, uniform heating, laborsaving, and absence of dirt constitute some of the advantages of this system

in the case of glass, where the product must be kept free from impurity. Galvanising tanks have also come under the oil-firing system. Generally speaking, the tanks are of a simple type, but require to bo supplied with uniform heat, and this' need has very successfully been met by the installation of fuel oil burners. While no very high temperature is required—only from 450 deg to 4Godeg C.—easy control within narrow limits is readily secured with oil fuel.

Another more example—that of the singeing of fabrics previous to dyeing and printing—may be cited. Here the cloth is passed over hot copper plates to burn off rapidly the loose iluff which has been produced in the weaving process, and thus to give a smoother surface. Oil firing, has been successfully applied in the rapid heating of the plates, and tile ready control of the temperature with little or no attention is a decided advantage. The system has now been in use for many years. Oil heating has also found numerous applications in the more ordinary work of the engineer. In the shipyards the heating-up of large plates and frames prior to bending had for some time been effectively dealt with in large oilfired furnaces. The time for heating up the furnace with oil is considerably less than with solid feul, and where only intermittent work is being handled the supply of oil can be readily adjusted. Hardening, annealing, and other types of heat-treatment furnaces are particularly suitable for the use of oil, and this fuel is, therefore, largely employed. While it may be that crude trials with ill-designed appliances have not given satisfactory results, it may be emphasised that gyery type of fuel combustion merits special design, and this is an aspect of the subject to which the makers of oil-fired furnaces have given considerable attention with very satisfactory results..