Fuel gas

“ In a steam engine the fuel can be used in any form, solid, liquid, or gaseous, but in an internal combustion, it must be in the form of a gas no matter what may have been the form of the primary fuel. Fortunately there is no fuel which may not be transformed into a gas by some process if not already in a gaseous state. The petroleum products are vaporized by 30either the heat of the atmosphere or by spraying them on a hot surface. Coal is converted into a gas by distilling it in a retort or by incomplete combustion. ”

“ While gas can yield the full fuel value of coal in a more efficient form than solid fuel, as well as all the commodity values, if it is converted into power through the steam engine, at least one-half of its energy value is lost. To conserve its full value, gas must be burned in the internal-combustion engine, the most familiar type of which is the one we know under the hood [Pg 99] of the automobile and the most efficient type is the Diesel engine which has made the by-product system industrially practical. ”

“ The process of making gas, which consists in blowing to incandescence the exterior portion of a body of fuel, forcing fresh fuel into the interior of the body, utilizing the sensible heat of the incandescent fuel in the destructive distillation of the fresh fuel, introducing steam into the interior portion of the body of fuel and causing it to pass, first through the fresh fuel and then through the heated exterior portion of the fuel bed. ”

“ In a similar way, air must be used in a gas engine in order that the fuel may burn. It is not possible to mix air with a liquid; the first step in making a gas that will burn is, therefore, to turn the fuel, whether it is gasoline, kerosene, distillate, or other oil, into a vapor ”

“ It is the use of gasoline for fuel that makes all this possible. Gasoline, being a very volatile liquid, turns into a highly inflammable gas when heated and mixed with the oxygen in the air. A tank holding from twenty to forty gallons of gasoline is connected, through an automatic regulator which controls the flow of oil, to a burner under the boiler. The burner allows the oil, which turns into gas on coming in contact with its hot surface, to escape through a multitude of small openings and mix with the air, which is supplied from beneath. ”

“ In passing into the incandescent fuel that fills the generator, the steam is decomposed, and there forms carbonic oxide, while hydrogen is liberated. The mixture of these two gases with the hydrocarburets furnished by the fuel constitutes water gas. This gas on making its exit from the generator through the pipe, M', passes through the chambers, B, and abandons therein the greater part of its heat, and enters the pipe, R, whence it passes through Q into the purifiers, and then into the gasometer. ”

“ Steaming and Combustion Tests.—The investigations included under the term, fuel efficiency, relate to the utilization of the various types of fuels found in the coal and oil fields, and deal primarily with the combustion of such fuels in gas producers, in the furnaces of steam boilers, in locomotives, etc., and with the efficiency and utilization of petroleum, kerosene, gasoline, etc., in internal-combustion engines. ”

“ From the economizer the gas is drawn through a wet scrubber where it undergoes a further cooling and is cleansed of dirt and dust. After passing the wet scrubber, the gas, under a light pressure, is forced, by the exhauster, through a dry scrubber to a gas-holder with a capacity of about 1,000 cu. ft.
All the fuel used is carefully weighed on scales which are checked from time to time by standard weights; and, as the fuel is charged into the producer, a sample is taken for chemical analysis and for the determination of its calorific power. ”

“ Strictly speaking, much, and sometimes even most, of the heating effected by solid or liquid fuel is actually performed by the gases given off during the combustion. We speak, however, of gaseous fuel only in those cases where we supply a combustible gas from the outset, or where we produce from ordinary solid (or liquid) fuel in one place a stream of combustible gas which is burned in another place, more or less distant from that where it has been generated. ”

“ The quantity of air necessary for the combustion of the fuel determines the amount of fuel that can be drawn into a given cylinder volume, and as we are dependent upon the fuel for the expansion it is evident that with two fuels of the same calorific value, the one requiring the least air will develop the most power. Since the air required to burn hydrogen gas is only one fourth of that required to burn the same amount of 17methane it is clear that more hydrogen can be burned in the cylinder than methane. ”

“ Other internal-combustion engines, as, for instance, the Priestman, Akroyd, and Knight engines, use common burning oils directly, and act as their own gas generators. Prof. Robinson urges that such dangerous and highly volatile hydrocarbons as benzoline, gasoline, and petroleum spirit should not be used as fuel in gas-engines. ”

“ It should be understood that fuel belongs to that class of substances that will not burn nor evolve energy under any temperature, pressure, or shock, without an outside supply of oxygen. This is the characteristic property of all fuels used with the internal combustion engine. Each element, such as carbon and hydrogen, in a compound fuel, develops a certain definite amount of heat during their complete combustion, and at the close of the process certain compounds are formed that 28represent the lowest chemical form of the compound. ”

“ To restore the products of combustion to their original form as fuel would require an expenditure of energy equal to that given out in the combustion.
While all substances that are capable of oxydization or combustion can be made to liberate heat energy, it does not follow that all of them can be successfully used as fuels. A fuel suitable for the production of power must be cheap, accessible and of small bulk, and must burn rapidly. Such fuels must also be products of nature that require no expenditure of energy in their preparation or completion. ”

“ In the case of a steam-boiler the energy of combustion is transmitted to water inside an air-tight vessel. The fuel does not actually touch the "working fluid." In the gas or oil engine the fuel is brought into contact and mixed with the working fluid, which is air. It combines suddenly with it in the cylinder, and heat energy is developed so rapidly that the act is called an explosion. Coal gas, mineral oils, alcohol, petrol, etc., all contain hydrogen and carbon. If air, which contributes oxygen, be added to any of these in due proportion, the mixture becomes highly explosive. ”

“ While the fuel most commonly used is coal, straw and wood, crude oil is often used, the fuel being determined principally by the location of the engine, and by its cost on the job. The matter of fuel should be taken into consideration when the engine is purchased as the different grades demand different fire box and boiler construction. When it is possible to obtain crude oil at a reasonable figure, it certainly should be used in preference to all others as liquid fuel is the most compact, most easily controlled, and efficient of any. ”

“ With the discovery and development of the oil wells in the United States about 1860 a new fuel was found in the crude petroleum, as well as a source of light. The application of petroleum to engines, either to produce furnace heat, or as introduced directly into the piston cylinder mixed with inflammable gas to produce flame heat and expansion, has given a wonderful impetus to the utilisation of gas engines. ”

“ Here the hydrogen and hydrocarbons react upon each other, producing a permanent gas, which is purified as usual. The resulting gas is of uniform quality, very pure, and the saving in labor and materials is about 35 per cent. over coal-gas (Scientific American, January 8, 1876) .
As regards the use of petroleum for fuel, it has always been found difficult to secure the complete combustion of the oil, so as to avoid smoke ”

“ In answer to your request with regard to my gas-lights, which I now have in my house, I take this mode of informing you, that I charge two retorts with 240lbs. of coal, half cannel and half Newcastle, from which I extract 1000 cubic feet of gas. To obtain this quantity of gas, when the retorts are cold, I use from 100 to 110lb. of common coals; but when they are in a working state, that is to say, when they are once red hot, the carbonising fuel amounts to about 25lb. ”

“ In introducing the oil it is not injected, but is simply allowed to flow in by gravity, at a point about half way up the column of fuel, the taps for its admission being placed at intervals around the circumference of the generator, and oil at first begins to flow down the inside wall of the generator, but being vaporized by the heat, the vapor is borne up by the rush of steam and water gas, and is cracked to a permanent gas in the upper layer of fuel. ”

“ For petroleum as a fuel under boilers in the generation of steam there are numerous substitutes, including wood, charcoal, coal, peat, natural gas, artificial gas, and electricity; as a fuel in internal-combustion engines some demonstrated substitutes are natural gas, artificial gas, benzol, and alcohol, and in the Diesel type of engine certain vegetable and fish oils can be utilized. ”

“ Air and fuel enter the producer at the top, and the gas exit is in the center of the bottom so that the air is forced to pass through the center of the producer, decomposing the volatile matter into gases of calorific value. The moisture which is present in the peat fuel in considerable quantities must be taken into consideration. ”

“ Petroleum products are also largely utilized in gas manufacture for, (1) the production of “air-gas,” (2) the manufacture of oil-gas, and (3) the enrichment of coal-gas. For heating purposes, the stoves employed are practically kerosene lamps of suitable construction, though gasoline is used as a domestic fuel in the United States. The use of petroleum as liquid fuel is dealt with under Fuel, as is the employment of its products in motors, which has greatly increased the demand for petroleum spirit. ”

“ The carburetter is a vessel in which the liquid fuel is converted into a combustible gas or Vapour, for, as there is no Connexion to any gas main, the ordinary petrol engine has to make its gas “on the premises.” The production of the gas is automatic, and calls for practically no attention from the driver, because, once the engine is started, the necessary aspiration to draw through the correct quantities of air and fuel is provided by the action of the valves and pistons. ”

“ Neglecting for the moment, all of the items that do not affect the operation of the engine from a power producing standpoint, the principal requirement of a fuel is the production of a high temperature in the cylinder since the output is directly proportional to the temperature range. Since a very considerable mass of air is to be raised to this high temperature, the heat value, or CALORIFIC VALUE of the fuel in British Thermal units is of as much importance as the temperature attained in the combustion. ”

“ A. Producer Gas, Siemens Gas.—As we have seen above, this gas is made by the incomplete combustion of fuel. The materials generally employed for its production are anthracite, coke or other fuels which are not liable to cake during the operation, and thus stop the draught or otherwise disturb the process, but by special measures also bituminous coal, lignite, peat and other fuel may be utilized for gas producers. The fuel is arranged in a deep layer, generally from 4 ft. ”

“ The air thus reached the burning fuel hot, instead of cold. By the use of two chambers used alternately to receive and give out the heat, the process was made continuous. By a further improvement gas was used in place of solid fuel, and this was passed through the ‘regenerator’ so that it arrived at the place of combustion in a highly heated state. Not only was there an enormous economy of heat, but the gas could be made from fuel of a very inferior sort, while processes could be conducted in the open furnace which could only be carried out in crucibles when solid fuel was employed. ”

“ Natural Gas the Fuel of the Future.—The house of the near future will have no fireplace, steam pipes, chimneys, or flues. Wood, coal oil, and other forms of fuel are about to disappear altogether in places having factories. Gas has become so cheap that already it is supplanting fuels. A single jet fairly heats a small room in cold weather. It is a well known fact that gas throws off no smoke, soot, or dirt. In a brazier filled with chunks of colored glass, and several jets placed beneath, the glass soon became heated sufficiently to thoroughly warm a room 10x30 feet in size. ”

“ Should the air be in excess of that required for complete combustion, or should a great quantity of incombustible gas, such as nitrogen be present in the mixture, the fuel will be completely burned, but the speed of burning will be reduced owing to the dilution. ”

“ Water boils in an uncovered vessel at 212 degrees Fahrenheit, and no amount of heat applied to it will make it any hotter. When a pot of food has reached the boiling point, a smaller flame will keep it boiling. Turn the gas as low as it may be safely turned and still keep the pot boiling, and the food will cook as rapidly as when the gas is turned on full.
Fig. 10. Single top burner
and valve.
Gas is a safe fuel in most hands; it saves the housekeeper much labor because it makes so little dirt. When properly managed, it is the cheapest fuel to be had at the present time. ”