Natural gas

“ Coincident with the discovery of petroleum, its inseparable companion, natural gas, came into prominence as a source of both light and heat, or this became true, at least, after it was ascertained that natural gas regions existed which could be tapped by wells, and made to give forth their gaseous product independent of the oil that may have at one time existed near or in connection with it. ”

“ Natural Gas, combustible gas which escapes from beneath the soil in such quantities that it may be used for fuel or illuminating purposes. In its natural state the gas occurs in porous sedimentary rocks, and, when proper openings are made, it rises to the surface. Wells are drilled for gas, as for oil or water. Natural gas is the product of decay or distillation of organic matter buried in sand, mud etc. ”

“ Fairbanks-Morse Producer Plant and Engine, Connected for Operation.
In practical work, the natural fuels are coal, mineral oils, natural gas, and wood, which are compounds of the elements carbon and hydrogen. When these fuels are burned to their lowest forms the products of combustion consist of carbon dioxide and water, the first being the result of the oxydization of carbon, and the latter a compound of oxygen and hydrogen. ”

“ These reservoirs of natural gas very frequently occur in sandstone, usually in the vicinity of coal-beds, but sometimes remote from them. In all cases the origin of the gas is thought to be in the destructive distillation, extending through long geological periods, of coal or of other vegetable or animal matter in the earth's interior. ”

“ Cobb, to what extent natural gas was used in the United States in 1887; that there were thousands of wells pouring out millions of cubic feet daily; that many of them showed pressure of from ten to twenty atmospheres. From the time you left the world, as it were, until August, 1916, gas wells were being sunk all over the country drained by the Ohio and its tributaries. Their number was way up in the thousands. Billions of cubic feet of natural gas were being consumed or flowing to waste daily. ”

“ In addition to the consumption of oxygen and production of carbonic acid by the use of common gas, the gas itself, owing to defectiveness of the burner, is projected into the air. Now, considering the deleterious nature of all illuminating gases, the reasons for perfect ventilation of rooms in which natural gas is used for heating and culinary purposes are self-evident, not alone as a protection against explosions, but for the health of the occupants of the house, remembering that a larger supply of oxygen is said to be necessary for the perfect combustion of natural than of common gas. ”

“ The class of liquid fuels is represented chiefly by petroleum, though coal tar and water-gas tar are used to a limited extent.
Gaseous fuels are limited to natural gas, blast furnace gas and coke oven gas, the first being a natural product and the two latter by-products from industrial processes. Though waste gases from certain processes may be considered as gaseous fuels, inasmuch as the question of combustion does not enter, the methods of utilizing them differ from that for combustible gaseous fuel, and the question will be dealt with separately. ”

“ Those gases which contain less methane contain all the more hydrogen, viz. 2.9 to 29.8%. There is also some ethylene, ethane and carbon monoxide, rarely exceeding 2 or 3%. The quantity of incombustible gases—oxygen, carbon dioxide, nitrogen—ranges from mere traces to about 5%. The density is from 0.45 to 0.55. The heating power of 1000 cub. ft. of natural gas is equal to from 80 to 120 ℔, on the average 100 ℔, of good coal, but it is really worth much more than this proportion would indicate, as it burns completely, without smoke or ashes, and without requiring any manual labour. ”

“ Natural Gas as a Source of Fuel.—An important change in the conditions of manufacturing in Pittsburg is promised by the introduction of natural gas as fuel in place of coal. The gas, which is principally carbureted hydrogen, or the fire-damp of the mines, is obtained abundantly in the neighborhood of the city, and even within its corporate limits, by boring wells. ”

“ The oxygen unites with the iron, while the hydrogen seizes on the carbon and rises to an upper level, where the vapors are condensed in part into mineral oil, and the rest remains in a state of natural gas. The petroleum strata are generally met with in the vicinity of mountains, and it may be granted that geological upheavals have dislocated the ground in such a way as to permit of the admission of water to great depths. ”

“ The rapid chemical action would raise the temperature of these gases, and thus increase their bulk immensely, which would produce an irresistible expansive force, which would increase the pressure against the sides of the cavern in which the gases were generated, and the ignition of the hydrogen would be a necessary consequence. Such an immense volume of gas being ignited, and confined, would produce such a degree of heat, as rapidly to decompose or melt the substances in its neighborhood, and set at 63 liberty a vast quantity of other gases ”

“ Let us take a Bunsen burner, in which the air and gas are freely mingled before they enter into combustion. If the air and the gas be properly proportioned, the combustion is so perfect that though a great deal of heat is produced there is but little light. The gas burned in this experiment ought to be the ordinary gas of our mains, which depends for its illuminating power on the circumstance that the hydrogen, of which the gas is chiefly composed, is largely charged with carbon. The illuminating power of the gas may indeed be measured by its available richness in carbon. ”

“ We know that, floating around us, these volatilized bodies exist in some material form, and numerous experiments in chemistry are calculated to convince us, that the most attenuated air is capable, with a slight change of circumstances, of being converted into the condition of solid masses. Hydrogen gas, the lightest, the most ethereal of the chemical elements, dissolves iron and zinc, arsenic, sulphur, and carbon; and from the transparent combinations thus formed, we can with facility separate those ponderous bodies. Such substances must exist in our own atmosphere ”

“ Gas thus produced is intensely hot; and as usually it contains sulphur, dust, dirt, and other admixtures, their removal by water in a scrubber would involve a waste of about 30 per cent. of the fuel heat. This loss is much diminished by sending into the producer not only air but steam, to be decomposed into oxygen and hydrogen; the oxygen combines with carbon to form more carbon monoxide, while the hydrogen is the most valuable heating ingredient in the emitted stream of gases. Were only air sent through the producer, the outflowing gases would contain nitrogen to the extent of 65 per cent. ”

“ The quantities of heat and light produced by the combustion of inflammable gases are by no means in the same constant relation to each other; one frequently increases, whilst the other diminishes; and this is eminently the case when coal gas and oil gas are burned against each other. The quantity of heat liberated is, speaking generally, as the quantity of gas consumed, and this is greatest with the coal gas; but the quantity of light is nearly as the quantity of carbon that is well burnt in the flame, and this is greatest in the oil gas. ”

“ Ellisen, of the Paris gas-works, have shown that the gases rich in carbon, such as defiant and acetylene, are developed chiefly during an interval of time, beginning half an hour after the commencement and terminating at half the whole period of distillation, while during the remainder of the time, marsh gas and hydrogen are chiefly developed, which, while possessing little illuminating power, are most advantageous for heating purposes. ”

“ The resulting water gas contains 60% of hydrogen and 20% of carbon monoxide, both of which are combustible gases. The proportions of the gases evolved can be varied at will by admitting more steam or using an excess of carbon ”

“ It might be expected that these gases would arrange themselves in our atmosphere in the above order, and if that were the case, we should have the carbonic-acid gas (a most poisonous one) at the bottom, and touching the earth, then the oxygen, and, last of all, [Pg 6] the nitrogen; a state of things in which organized life could not exist. The gases do not, however, separate: indeed, they seem to act as it were like vacuums to one another, and "the diffusion of gases" has become a recognised fact, governed by fixed laws. ”

“ Yet it is one whose form can be changed, and whose hardness can be completely destroyed, by the simple process of combustion. It can be deprived of its high lustre, and of its power of breaking up by refraction the light of the sun into the various tints of the solar spectrum, simply by heating it to a red heat, and then plunging it into a jar of oxygen gas. It immediately expands, changes into a coky mass, and burns away. The product left behind is a mixture of carbon and oxygen, in the proportions in which it is met with in carbonic-anhydride, or, carbonic acid gas deprived of its water. ”

“ It will be remembered that the amount of gas obtained by distillation, from the very best coal, ranged between 10,000 and 16,000 cubic feet. Water-gas contains as a rule 40 to 50 per cent, of hydrogen, 30 to 40 per cent, of carbonic oxide, 10 per cent, of naphtha or petroleum gas, and a few per cent, of carbonic acid. The large proportion of heavy petroleum-gas (sp. gr. 0.600 to 0.700) and carbonic oxide (sp. gr. 0.967) makes its specific gravity much heavier than that of coal gas ”

“ When we light the fire we set going the process which we call combustion, or burning, and, as we know from our own experience, that process causes heat to be generated.
What takes place in the fire-grate is that the carbon of the coal enters into combination with oxygen from the air, the two together forming a new compound called "carbonic acid gas." There is nothing lost or destroyed in this process, the carbon and oxygen simply changing into the new substance, and could we weigh the gas produced we should find that it agreed precisely with the weight of the carbon and oxygen consumed. ”

“ I want almost—not quite—actual flame to fire coal gas. But here is another gas, about which I may have to say something directly, called marsh gas (the gas of coal-mines) . This requires a much higher temperature than even coal gas to fire it. I want you to understand that although all gases require heat to fire them, different gases ignite at very different temperatures. Bisulphide of carbon gas, e. g., ignites at a very low temperature, whilst marsh gas requires a very high temperature indeed for its ignition. You will see directly that this is a very important fact. ”

“ The gas from the gas-works is the hydrogen of the coal separated from the carbon. When we heat it with a match to set it to uniting with oxygen, we have nothing but a flame. You know the coal is heated in air-tight retorts; it is heated hot enough to burn, but it can't burn because there is no oxygen for it to unite with; but the heat causes the hydrogen to separate from the carbon, and then it finds its way out through the opening in the retort into the pipes, and when it reaches the air at the end of a pipe, you can heat it a little with a match, and it will begin to unite with the oxygen. ”

“ By such expansion heat is absorbed and the temperature of the surroundings is lowered. From the coolers the gas returns to the absorber, from which it is pumped, in liquid form, into the retort, to be again heated, the gas expelled and the process repeated. As the gas passes through the different processes, being heated under pressure, cooled, expanded again, more or less decomposition takes place, presumably from a combination of a small portion of the nitrogen with vegetable, animal, or mineral matter that finds its way into the system. ”

“ Both coal and oil-gas develop a great amount of heat in proportion to the light they yield. The hydrogen they contain in large quantities burns, when pure, with an almost invisible flame, but more hotly than any other known gas. The particles of carbon also present in the flame are heated to whiteness by the hydrogen, but they are not sufficient in number to convert more than a fraction of the heat into light. ”

“ Oxygen and Atmosphere.—The atmosphere is not oxygen. Only one-fifth of common air is oxygen, the residue being, principally, nitrogen, which is not a fuel. To produce the proper aëration, therefore, at least fifteen parts of air must be mixed with one part of hydro-carbon gas.
The term hydro-carbon is applied to petroleum, and its products, because the elements carbon and hydrogen make up the largest part of the oil, whereas this is not the case with most of the other oils. ”

“ It is clear that were any texture known which would permit a heat-impulse to pass through it in one direction only, nothing more would be necessary than to place a portion of gas in such a receptacle of this substance, so faced as to permit egress but not entrance of the heat, and the gas thus enclosed, were it hydrogen itself, would very soon become liquid and solid, through spontaneous giving off of its energy, without any manipulation whatever. ”

“ When the intensity of the heat has reached a certain degree, a part of the carbon unites with part of the oxigen and produces carbonic acid, which by means of caloric is melted into the gazeous state and forms carbonic acid gas; at the same time, part of the hidrogen of the coal combines with another portion of carbon and caloric, and forms the carburetted hidrogen gas, which varies considerably in its constitution, according to the circumstances under which it is produced; a portion of olifiant gas, carbonic oxid, hidrogen, and sulphuretted hidrogen, is also produced during the process. ”