WATER GAS.

South Canterbury Times, Issue 4980, 12 April 1889, Page 3

WATER GAS.

THE FUEL AND LIGHT OP THE FUTURE, At a meeting of the Hull Institution oi Engineers and Naval Architects on Feb. 9th, a very interesting paper by Mr Samson Fox, C. 8., of Leeds Forge was read on the subject water gas. The invention, it was stated, is an agglomeration of several inventions which have jointly produced a perfect and safe process for the production of water gas. The operations at Leeds Forge are largely conducted with pas fuel, and the gas produced by ordinary generators, or the town supply, being neither cheap enough nor of sufficiently high heating power, searching investigations were made by Mr Fox into the applicability of water gas, which resulted in the establishment of a process which more than equalled the previous desires of the company. The apparatus finally adopted is extremely simple, and requires no skilled labour for its manipulation. Water-gas is a gas produced from water by a chemical reaction which takes place in passing steam through incandescent combustible matter. Tho ordinary laboratory experiment of passing steam through a highly heated iron tube, filled with iron scraps or iron filings,in which tho steam becomes decomposed into its constituent gases, is the original of the water-gas generator. In the case of tho iron the water is split up into its elementary gases, hydrogen and oxygon. The oxygen combines with the iron, forming oxide of iron or rust, and the hydrogen remains free, passes through, and may be lighted at the mouth of tho tube. In the water-gas iron in the retort is replaced by coal or other carbonaceous matter, which is ignited and forced to a high temperature by means of a blast. The air blast is then shut off and steam turned on so long as the charge retains sufficient heat for the purpose. As in the experiment referred to, the heat of tho charge decomposes the steam into oxygen and hydrogen, the hydrogen remains free, while the oxygen combines with carbon to form a combustible gas, 'carbon-oxide. The difference between the two processes is that the oxide of iron formed in the laboratory experiment is a solid substance and noncombustible, while in tho water-gas apparatus the oxide of carbon, or carbon-oxide, is in a

gaseous state and combustible. Hydrogen, i is needless to state, is also combustible. Thi two gases are mixed in about equal proper tions, and the combustible percentage o: water gas is about 95. The operation is ar intermittent one. First, the charge oi carbonaceous matter having been well ignited is raised to a high temperature by an aii blast. "When it is sufficiently hot the blast if shut off, and steam .turned on, making watergas, by which operation the charge is cooled The steam is then turned off, and the blast restored until the charge is thoroughly reheated. The writer states that in his retorts the gas making continues about foui minutes during which time some 4500 feet oi water-gas is produced. He (at all events his reporter) does not state how long the blast requires to reheat the the charge. Even the products of the air blast combustion are useful. The gas issuing from the retort while the air blast is on consists of about 32 per cent of wbat may be called low-grade carbonio oxide —an oxide which will further combine with oxygon and is therefore further combustible —mixed with the nitrogen of tboair delivered by the blast. This mixture is called “ producer gas, ” and may be employed whore any moderate heat is required. At Leeds Forge, this “ producer gas," as it is called, to distinguish it from tho water or " generator gas,” is used in some of the furnaces, being carried to them in brick-lined tubes, so that it shall retain as much heat as possible ; or it may be stored and burned in the usual way. The fact that the producer gas is combustible is due to the high heat of the charge disallowing tho oxygen of the blast to pick up or combine with so great a proportion of carbon as it would do at a lower temperature, consequently a further combination of these elements——in other words, further combustion—is possible afterwards. The valves controlling the alternate egress of ‘‘producer” and “ generator ” gas from the generator are somewhat complicated in structure, as they have to be cellular and water-jacketed to protect them from the heat. That, however, is a mere detail. Their management is quite simple. All the valves being connected in order, a single lover operated by the engine producing the air blast controls them automatically. It will thus be seen that the process consists of alternately blowing the generator hot, and making gas, by which action the fuel becomes cooled, and the operation must be repeated. The gas is entirely free from tar and ammoniacal liquors, and absolutely fixed and noncondensible. From the generator the gas passes to the scrubber, which separates the Bust carried forward, and thence to the gas-holder, whence it is taken to the purifiers. This is the reverse of the process usually followed in gasworks, and is necessary because the make of gas is intermittent and very great during generating, so that tho purifiers would become surcharged and unable to purify on account of tho speed of the passage of the’gas per square foot of purifying area. No exhauster is necessary nor condensers, and purification ia effected by iron, no limo being required, as there is only a very small percentage of carbonic acid. The purifiers are of the ordinary type, controlled by a centre valve. The fuel used may be the cheapest form of coke, either mixed with coal or used alone. The consumption per hour in the generators used at Leeds Forge is about lOowt per hour, yielding from 15,000 to 18,000 feet of watergas. The cost of gas will depend upon the quantify made, cost of fuel, and of labour; with fuel at 8s per ton, labour at 3s fid par man per day, and tho generator fully employed, the gas costs per 1000 cubic feet about 4d. Besides being used for metallurgical purposes the offices and parts of the works are lighted with water-gas. The gas by itself burns with a deep blue noa-luminous flame, and for lighting purposes a jet is employed to heat to incandescence a “ comb ” composed of magnesia rods suspended by a wire over the gas burner. The flame renders these rods white hot, producing an intensely bright light. With a consumption of sfb per hour, the combs give a light equal to 22 eandles by photomertic test. Tho colour of the light is white, with a very slight tint of blue, and the pipe arrangements and gasfittings in the office and buildings required no alteration. This system of lighting has been adopted with great success in towns and works on the continent (and at a railway station where the signals and switch lamps are lighted by it), and it offers a convenient and beautiful means of illuminating, possesses all the conveniences of coal gas,without its disadvantages has the brilliancy of the electric light at considerable less cost than either. Less heat is given off than wish coal gas, it is entirely free from smoke, and the products of combustion are less injurious to health and furniture than those from ordinary coal-gas. This is proved by the fact that plants will net only live but thrive in a room warmed and lighted with water-gas. The light by means of the incandescent combs is much more agreeable on account of its whiteness and perfect steadiness, than the ordinary gas flame, and as the area of glowing material is larger and the colour of the light better, it is found to be less trying to the eyes than the incandescent electric light. With this latter the very small area which is rendered intensely hot for the emission of light, produces a painful effect upon tho retina of the eye and soon becomes distressing and even injurious. The combs last about a hundred hours, cost about l£d each, and can be re-

placed in a moment. One defect of watergaa in relation to its use for domestic purposes is its entire freedom from smell. A leak from the domestic supply pipes or mains would as a rule be only discovered by the effects of an explosion. In order to avoid this means arc adopted to impart to it an artificial and powerpowerful; odor, so that escapes may be detected at once. Water-gas heating and cook-

ing stoves are run without the aid of the Bunsen air ball, ordinary pipes drilled with holes being all that it necessary. The application of water-gas to gas engines has proved eminently [satisfactory. In a trial of days’ duration with a six-horse power Otto engine, it was found that the consumption of ' per horse horse po\yer per hour was at a

cost of four-tenths of a penny, and that owing to the absence of hydrocarbons from water-gas, the amount of tarry deposit in the valves, ports, passages, and cylinders was nil, the lubricating oil was not carbonized to nearly so great an extent, the quantity of water used was less than before, and with water-gas the engines worked safer and with far less difficulties than had been met with in ordinary practice.