Water gas

“ When steam is passed over red-hot charcoal, hydrogen is also produced with carbonic oxide gas, and this in fact is the ordinary process of making water gas, which being purified is afterwards saturated with some volatile hydrocarbon and burnt. At first sight, such a mode of making gas would be thought extremely profitable, and in spite of the numerous failures the discovery (so called) of water gas is reproduced as a sort of chronic wonder ”

“ Water-gas made from steam and oil is usually limited to those places where the raw materials are readily available. The composition of a gas determines its heating and illuminating values, and constituents favorable to one are not necessarily favorable to the other. Coal-gas usually is of lower illuminating value than carbureted water-gas. It contains more hydrogen, for example, than water-gas and it is well known that hydrogen gives little light on burning. ”

“ 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 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 ”

“ It constitutes two-thirds of the volume of the gases resulting from the decomposition of water, and one-ninth of the weight. Compute the latter from its symbol. It is a constituent of plants and animals, and some rocks. Considering the volume of the ocean, the total amount of H is large. It can be separated from H2O by electrolysis, or by C, as in the manufacture of water gas.
When burned with O it forms H2O. Pure O and H when burning give great heat, but little light. The oxy-hydrogen blow-pipe (Fig. 17) is a device for producing the highest temperatures of combustion. ”

“ Not only is the ammonia obtained in the manufacture of the gas of great importance, but the coal tar also serves as the source of many very useful substances, as will be explained in Chapter XXXII.
Water gas. Water gas is essentially a mixture of carbon monoxide and hydrogen. It is made by passing steam over very hot anthracite coal, when the reaction shown in the following equation takes place:
C + H2O = CO + 2H.
When required merely to produce heat the gas is at once ready for use. ”

“ By-and-by the water will be continued right up to the roof, and it will surprise some people to learn that the gas, when it enters the holder, rests on the water and forces the holder up, so that when the holder is full its top is on a level with that of the upright girders which guide its actions, and its bottom only a foot or so beneath the surface of the water, the latter being in a giant stone tank. Water, it should be understood, is an absolute seal for gas, and it is a practical impossibility that a gasholder could, as many imagine, blow up. ”

“ It has been seen that the gas of common coal is of comparatively poor illuminating power, unless enriched by the gas of other coals or of petroleum, and that water-gas of itself possesses no illuminating power whatever. ”

“ As the production of water gas implies the absorption of a large quantity of sensible heat, it is accompanied with a rapid fall of temperature in the chambers, B', and eventually also in the generator, A, while at the same time the chambers, B, are but moderately heated by the sensible heat of the current of gas produced. ”

“ Water, flowing over a bed of this mineral, liberates the gas in the form of an almost invisible vapor. It is swept forward in a cloud by the wind, some of it is carried along above the course of the underground stream, and as soon as it reaches an opening in the earth, like a fissure crack in the rock or ground, the gas rises and whoever breathes it dies or is rendered unconscious for a time, according to the strength of the vapor. ”

“ As water gas, possessing these properties, may be prepared at central works and conveyed in pipes to the consumers, and as it may be produced from any kind of fuel, and ought to be much cheaper than ordinary gas, it may as a matter of fact be expected that in course of time (when experience shall have determined the cheapest and best way to prepare it) it will not only supplant ordinary gas, but will with advantage everywhere replace the ordinary forms of fuel, which in many respects are inconvenient. ”

“ Beds of coal are frequently pierced by the borers for salt water; and the inflammable gas is forced up in jets twenty or thirty feet in height. From these fountains the vapour has been conveyed to the salt-works in pipes, and there used for the boiling and evaporation of the salt; other tubes convey the gas intended for lighting the streets and the larger apartments and kitchens. As there is still more gas than required, the excess is conducted beyond the limits of the salt-works, and there forms separate chimneys or columns of flame. ”

“ Perfectly pure water is without taste: even the pleasant character of freshly-drawn spring-water is due to the admixture of atmospheric air and carbonic acid. The manner in which water absorbs air is evidently due to a peculiar physical attractive force, the value of which we do not at present clearly perceive or correctly estimate. It is chemically composed of two volumes of hydrogen gas—the lightest body known, and at the same time a highly inflammable one—united with one volume of oxygen, which excites combustion, and continues that action,—producing heat and light,—with great energy. ”

“ It will be obvious, that when a gas holder of this construction becomes immersed in the water, it loses as much of its weight as is equal to the bulk of water which it displaces, and hence to render its descent uniform, and to preserve the gas within, of an invariable density, at any degree of immersion, a greater counterpoise is required as the gas holder rises out of the water. ”

“ As the water is forced to the surface, the pressure diminishes, and a portion of gas escapes with effervescence. The spouting wells deliver, therefore, enormous volumes of gas with the water, a perfect suds of water, carbonic acid and carburetted hydrogen.
"The common origin of the springs is shown by the analysis: all contain the same constituents in essentially the same order of abundance; they differ in the degree of concentration merely. Those from the deepest strata are the most concentrated. ”

“ The water, which results from the combination of the hydrogen of the gas with the oxygen of the air, is deposited in most cases at the bottom of the exhaust-chest. It is advisable to fit a plug or iron cock in the base of the chest. Alkaline or acid water will always corrode a bronze cock. ”

“ Now upon opening the tap H, this superior gas forces out the mixture of water and liquid carbon dioxide, which suddenly expanding causes portions of the globules of liquefied gas to be frozen, and these, being protected by a rapidly evaporating portion of the liquefied gas, are thrown on the fire in solid particles. ”

“ At the same time that the extreme levity of the hydrogen gas accounts for the great quantity of heat which it holds in combination, and the high temperature requisite to effect its decomposition, and that such is its capacity for heat, that though combined with oxygen and water, it still possesses the property of absorbing a great deal more. ”

“ Gas made from ammonia when subjected to a pressure of about one hundred and fifty pounds to the square inch, becomes a liquid. Should the pressure be now removed, the liquid ammonia will instantly rush into gas again, and in doing so tries to absorb the heat which has been squeezed out of it.
If this expansion into gas be allowed to take place in pipes sunk in brine, it will draw all the heat out of the brine, and cause the brine to become cold enough to freeze fresh water in cans suspended in it, and convert the fresh water in the cans into solid ice. ”

“ Oxygen gas may be collected in the usual way, either over water, mercury, or in bags; or, on the large scale, in gasometers. The purity of the products of the several processes given above depends on the substances from which the gas is obtained being themselves pure. For particular experiments the first portion of gas should be allowed to escape, or be received apart, as with this, as with the other gases, it is contaminated with the atmospheric air of the apparatus. The gas procured from manganese or nitre may be purified by passing it through milk of lime or a solution of caustic potash ”

“ The gas-light apparatus, therefore, consists simply in a large iron vessel, in which the coals are exposed to the heat of a furnace,—some reservoirs 242 of water, in which the gas deposits its impurities,—and tubes that convey it to the desired spot, being propelled with uniform velocity through the tubes by means of a certain degree of pressure which is made upon the reservoir. ”

“ 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 notion of partially drying a gas by causing it to pass through water may appear paradoxical, but a comprehension of physical laws will show that it is possible, and will prove efficient in practice, when due attention is given to the facts that the gas entering the washer is hot, and that it is subsequently to be stored over water in a holder. ”

“ By the aid of pressure and of low temperatures, the force of cohesion may be so far increased in many gases that they are readily converted into liquids, and we know now that with sufficient pressure and cold they may all be liquified. On the other hand, heat, which increases the vis viva of the molecules, converts liquids, such as water, alcohol and ether or gas into the aëriform state in which they obey all the laws of gases. The aëriform state of liquids is known by the name of vapor, while gases are bodies which, under ordinary temperature and pressure, remain in the aëriform state. ”

“ In efficiency. Mere water inadequately applied feeds the fire, but carbonic acid gas never. Bulk for bulk, it is forty times as effective as water, the seventy gallons of the two smallest cylinders being equal to twenty-eight hundred gallons of water. Besides, it uses the only agent that will extinguish burning tar, oil, and other combustible fluids and vapors. One cylinder can be recharged while the other is working, thus keeping up a continuous stream.
4th. In convenience. Five or six men can draw it and manage it. ”

“ Certain firms make pure carbon dioxid (commercially known as carbonic acid [pg 366] gas) and compress it in iron tanks. These iron tanks of carbon dioxid (CO2) are shipped to soda-water fountains and soda-bottling works. Here the compressed carbon dioxid is dissolved in water under pressure,—this is called "charging" the water. When the charged water comes out of the faucet in the soda fountains, or out of the spout of a seltzer siphon, or out of a bottle of soda pop, the carbon dioxid that was dissolved in the water under pressure bubbles up and escapes,—the soda water effervesces. ”

“ In other words, the expanding gas having absorbed much heat from the brine, and having been made cold by this means, must be deprived of the heat thus gained by compression again into a coil surrounded by running water, which takes away the heat as soon as it is developed by compression.
Being now restored to the liquid form, the gas is ready to go on another round, and may be used again and again. The only loss of gas sustained is from leaky joints in the pipes. ”

“ Just as opening the valve lets the vapor accumulated above the water in Papin’s digester escape, and causes a fall in the temperature, so, by opening the reservoirs in which one has confined a liquefied gas, one sees it fall back to the boiling point. For example, take the liquid obtained from the compression of sulphurous acid gas. As soon as the reservoir containing it is opened the liquid begins to boil, and a vapor is formed, it is the gas which re-forms. ”

“ And further, that the solvent power increases with pressure, and the sloution of the gas in a liquid is the principle of the invention.
The process described as carried on, though subject to modifications, is as follows: The gas is dissolved in the liquid chosen, and the 'solution under pressure, however obtained, is filled into a receiver of metal or of glass (such as used for soda water) capable of resisting the pressure employed. ”

“ There is always a thick stratum of this deadly gas incumbent on the surface of the water. There is an admixture of sulphuretted hydrogen gas with the carbonic. All the experiments that are made on animals at the famous Grotto del Cane, near Naples, may be repeated here with perfect success. The Marienbrunn is more elevated than the bathing-establishments, so that the water is conveyed fresh from the source, through pipes that prevent all decomposition. ”

“ In any case, where a stream of air or oxygen is employed, an exceedingly fine jet should be used, in order that the expelled gas may take the form of a stream of minute bubbles; for, as previously stated, the water can absorb the gas only very slowly, so that there must necessarily be a considerable waste when the gas issues rapidly. Further, the smaller the bubbles passing through the water, the greater is the total surface of gas in contact with the liquid, the volume of the supply being the same, and hence the more effectually will the solution of the gas proceed. ”