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labour to manage them, is all that is necessary for the transit riveted and tested, so as to form a storage tank. From this tank and combustion of petroleum fuel; and it is certain that even a feed-pipe is led to a burner of the combined steam-and-oil in England will be found places which, from topographical type already indicated, and this burner is so arranged

Liquid and other circumstances, will use petroleum more economically as to enter a short distance inside the furnace than coal as fuel for manufacturing purposes under reasonable mouth. The ordinary fire-bars are covered with a thin facer conditions of price for the fuel.

layer of coal, which starts the ignition in the first

motives The theoretical calorific value of oil fuel is more nearly realized place, and the whole apparatus is ready for work. The burner in practice than the theoretical calorific value of coal, because best adapted for locomotive practice is the Holden Burner the facilities for complete combustion, due to the artificial (fig. 1), which was used on the Great Eastern railway. The admixture of the air by the atomizing process, are greater in steam-pipe is connected at A, the oil-pipe at R, and the hand

wheels C and D are for the adjustment of the internal orifices according to the rate of combustion required. The nozzle E is directed towards the furnace, and the external ring FF, supplied by the small pipe G and the by-pass valve H, projects a series of steam jets into the furnace, independent of the injections of atomized fuel, and so induces an artificial inrush of air for the promotion of

combustion. This type of burner has also NOI SI2C BUANCA

been tried on stationary boilers and on board ship. It works well, although the great consumption of steam by the supplementary ring is a difficulty at sea, where the water lost by the consumption of steam cannot easily be

Although the application of the new fuel for land and locomotive boilers has already been large, the practice at sea has been far more extensive. The reason

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at sea. is chiefly to be found in the fact that although the sources of supply are at a distance from Great Britain, yet they are is countries to whose neighbourhood British steamships regularly trade, and in which British naval squadrons are regularly stationed,

so that the advantages of adopting liquid fuel FIG. 2.-Rusden and Eeles Burner.

have been more immediate and the economy the case of oil than coal, and for this reason, among others, the more direct. The certainty of continuous supply of the fuel and practical evaporative results are proportionately higher with the wide distribution of storage stations have so altered the liquid fuel. In some cases the work done in a steam-engine by conditions that the general adoption of the new fuel for marine 2 tons of coal has been performed by i ton of oil fuel, but in purposes becomes a matter of urgency for the statesman, the others the proportions have been as 3 to 2, and these latter can be merchant and the engineer. None of these can afford to Deglect safely relied on in practice as a minimum. This saving, combined the new conditions, lest they be noted and acted upon by their with the savings of labour and transit already explained, will competitors. Storage for supply now exists at a number of sea in the near future make the use of liquid fuel compulsory, except ports. London, Barrow, Southampton, Amsterdam, Copenin places so near to coal-fields that the cost of coal becomes hagen, New Orleans, Savannah, New York, Philadelphia, sufficiently low to counterbalance the savings in weight of fuel Singapore, Hong Kong, Madras, Colombo, Suez, Hamburg, consumed and in labour in handling it. In some locomotives Port Arthur, Rangoon, Calcutta, Bombay, Alexandria, on the Great Eastern railway the consumption of oil and coal Bangkok, Saigon, Penang, Batavia, Surabaya, Amoy, Swatox, for the same development of horse-power was as 17 lb oil is Fuchow, Shanghai, Hankow, Sydney, Melbourne, Adelaide, to 35 lb coal; all, however, did not realize so high a result. Zanzibar, Mombasa, Yokohama, Kobe and Nagasaki; also

The mechanical apparatus for applying petroleum to steam in South African and South American ports. raising in locomotives is very simple. The space in the tender The British admiralty have undertaken experiments with usually occupied by coal is closed up by steel-plating closely | liquid fuel at sea, and at the same time investigations of the


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possibility of supply from sources within the regions of the efficiency based on the thickest armour, the heaviest and most British empire. There is an enormous supply of shale under the numerous guns, the highest maximum speed, and, last and not north-eastern counties of England, but no oil that can be pumped least, the greatest range of effective action based upon the -still less oil with a pressure above it so as to “gush ” like the maximum supplies of fuel, provisions and other consumable wells in America-and the only sources of liquid supply under the stores that the ship can carry. Now, if by changing the type British flag appear to be in Burma and Trinidad. The Borneo I of suel it be possible to reduce its weight by 30%, and to abolish

the stokers, who are usually more than half the ship's company, the weight saved will be represented not merely by the fuel, but by the consumable stores otherwise necessary for the stokers. Conversely, the radius of effective action of the ship will be doubled as regards consumable stores if the crew be halved, and will be increased by 50% if the same weight of fuel be carried in the form of liquid instead of coal. In space the gain by using oil fuel is still greater, and 36 cubic feet of oil as stored are equal in practical calorific value to 67 cubic feet of coal according to the allowance usual for ship's bunkering. On the other hand, coal has been relied upon, when placed in the side bunkers of unarmoured ships, as a protection against shot and shell, and this advantage, if it really exists, could not be claimed in regard to liquid fuel.

Recent experiments in coaling warships at sea have FIG. 4.-Installation on ss. "Trocas."

not been very successful, as the least bad weather has fields are not under British control, although developed prevented the safe transmission of coal bags from the collier to entirely by British capital. The Italian admiralty have fitted the ship. The same difficulty does not exist for oil fuel, which several large warships with boiler apparatus to burn petroleum. has been pumped through flexible tubing from one ship to the The German admiralty are regularly using liquid fuel on the other even in comparatively rough weather. Smokelessness, China station. The Dutch navy bave fitted coal fuel and liquid so important a feature of sea strategy, has not always been fuel furnaces in combination, so that the smaller powers required I attained by liquid fuel, but where the combustion is complete,

by reason of suitable furnace arrangements and careful management, there is no smoke. The great drawback, however, to the use of liquid fuel in fast small vessels is the confined space allotted to the boilers, such confinement being unavoidable in view of the high power toncentrated in a small bull. The British admiralty's experiments, however, have gone far to solve the problem, and the quantity of oil which can be consumed by forced draught in confined boilers now more nearly equals the quantity of coal consumed under similar con

ditions. All recent vessels built for the British FIG. 5.-Details of Furnace, Meyer System.

navy are so constructed that the spaces between

their double bottoms are oil-tight and capable may be developed by coal alone, and the larger powers by of storing liquid fuel in the tanks so formed. Most recent battlesupplementing coal fuel with oil fuel. The speeds of some ships and cruisers have also liquid fuel furnace fittings, and in vessels of the destroyer type have by this means been accelerated 1910 it already appeared probable that the use of oil fuel in war. Dearly two knots.

ships would rapidly develop. The questions which govern the use of fuel in warships are In view of recent accusations of insufficiency of coal storage in more largely those of strategy and fighting efficiency than foreign naval depots, by reason of the allegation that coal so

economy of evaporation. Indeed, the cost of construct- stored quickly perishes, it is interesting to note that liquid fuel Adres. tages in

ing and maintaining in fighting efficiency a modern may be stored in tanks for an indefinite time without any varstips. warship is so great that the utmost use strategically deterioration whatever.

must be obtained from the vessel, and in this compari- In the case of merchant steamers large progress has also been son the cost of fuel is relatively so small an item that its increase made. The Shell Transport and Trading Company have twenty

one vessels successfully navigating in all parts of the Advan.

world and using liquid fuel. The Hamburg-American tages la iaro Steamship Company have four large vessels similarly merchant

ships. fitted for oil fuel, which, however, differ in furnace arrangements, as will be hereafter described, although using coal when the fluctuation of the market renders that the more economical fuel. One of the large American transatlantic lines is adopting liquid fuel, and French, German, Danish and American mercantile vessels are also beginning to use it in considerable amounts.

In the case of very large passenger steamers, such as those

of 20 knots and upwards in the Atlantic trade, the saving in cost FIG. 6-Details of Exterior Elongation of Furnace, Meyer System. greater weight and space available for freight. Adopting a basis

of fuel is trifling compared with the advantage arising from the or decrease may be considered almost a negligible quantity of 3 to 2 as bet ween coal consumption and oil consumption, The desideratum in a warship is to obtain the greatest fighting there is an increase of 1000 tons of dead weight cargo in even a

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ships, whilst considerable additional speed is obtainable. The cost of the instalistion, however, is very considerable, as it includes not only burners and pipes for the furnaces, but also the construction of oil-tight tanks, with pumps and numerous valves and pipe connexions.

Fig. 2 shows a burner of Rasden and Eeles patent as generally used on boerd ships' for the purpose of injecting the oil A is a movable cap holding the packing B. which renders the annular spindle M oil and steam tight. E is the outer casing coataining the steam jacket from which the stean. after being fed through the steam-supply pipe G, passes into the annular space sur rounding the spindle P. It will be seen that if the spindle P be travelled inwards by turning the handle N, the orifice at the nozzle RR will be opened so as to allow the steam to flow out radially. If at the

same time the annular spindle M be drawn FIG. 7.–Furnace on ss." Ferdinand Laeisz." A, it is proposed to do away with this ring which passes through the supply pipe F .

inwards by revolving the handle L, the of brickwork as being useless; B, it is proposed to fill this space up, thus continuing lining also have emission at RR, and, coming in of furnace to combustion chamber, and also to fit protection bricks in way of saddle plate.

contact with the outflowing steam, will be



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medium-sized Atlantic steamer, and a collateral gain of about pulverized and sprayed into the furnace. Fig. 3 is a profile and 100,000 cub. ft. of measurement cargo, by reason of the ordinary plan of a steamer adapted for carrying oil in bulk, and showing bunkers being left quite free, and the oil being stored in the double all the storage arrangements for handling liquid fuel. Fig. 4 short bottom spaces hitherto unutilized except for the purpose of the interior arrangement of the boiler furnace of the steamstip

the ordinary water ballast. The cleanliness and saving of time from bunkering fire-bars, B is a brick bridge, C a casing of fire-brick intended by the use of oil fuel is also an important factor in passenger to protect the riveted seam immediately above it from the direct

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impact of the flame, and D is a lining of fire-brick at the back of the not till 1821 that it was turned to use at Fredonia, N.Y. In combustion-box, also intended to protect the plating from the direct Pennsylvania natural gas was discovered in 1859, but at first impact of the petroleum flame. The arrangement of the furnace on the Meyer system is shown in fig. 5, where E is an annular pro- very little use was made of it. Its industrial employment dates jection built at the mouth of the surnace, and BB are spiral passages only from 1874, and became of great importance about ten for heating the air before it passes into the furnace. Fig. 6. shows years later. Nobody ever doubted that the gas found in these the rings CC and details of the casting

which forms the projection localities was an accumulation of many ages and that, being or exterior elongation of the furnace. The brickwork arrangement adopted for the double-ended boilers on the Hamburg-American tapped by thousands of bore-holes, it must rapidly come to an Steamship Company's " Ferdinand Laeisz" is represented in fig. 7: end. This assumption was strengthened by the fact that the The whole furnace is lined with fire-brick, and the burner is mounted gas-wells," which at first gave out the gas at a pressure of 700 upon a circular disk plate which covers the mouth of the furnace.

or soo, sometimes even of 1400 lb per sq. in., gradually showed The oil is injected not by steam pulverization, but by pressure due to a steam-pump. The oil is heated to about 60°C. belore entering a more and more diminishing pressure and many of them ceased pump, and further heated to 90° C. after leaving the pump. It to work altogether. About the year 1890 the belief was fairly

is then filtered, and passes general that the stock of natural gas would soon be entirely to the surnace injector C at exhausted. Indeed, the value of the annual production of natural its passage through this in- gas in the United States, computed as its equivalent of coal, jector and the spiral pass- was then estimated at twenty-one million dollars, in 1895 at ages of which it consists twelve millions, in 1899 at eleven and a half millions. But the pulverizes the oil into spray: output rose again to a value of twenty-seven millions in 1901, in which form it readily and to fifty million dollars in 1907. Mostly the gas, derived interior of the furnace. The from upwards of 10,000 gas-wells, is now artificially compressed injector is on the Körting to a pressure of 300 or 400 lb per sq. in. by means of steamby fracture of the liquid oil power or gas motors, fed by the gas itself, and is conveyed over arising from its own mo

great distances in iron pipes, from 9 or 10 to 36 in. in diameter. mentum under pressure. In 1904 nearly 30,000 m. of pipe lines were in operation. In The advantage of this 1907 the quantity of natural gas consumed in the United States

system as compared with (nearly half of which was in Pennsylvania) was 400,000 million FIG. 10.-Section through Furnace of ss.

Canada (Ontario) also produces Murex.

saving of fresh water, the cub. ft., or nearly 3 cub. m.

abstraction of which is so some natural gas, reaching a maximum of about $746,000 in injurions to the boiler by the formation of scale.

1907. The general arrangement of the fuel tanks and filling pipes on the s. “Murex" is shown in fig. 8; and fig. 9 represents the furnace CH, of which it contains from 68.4 to 94.0% by volume. Those

The principal constituent of natural gas is always methane, rear of the same vessel, A being the steam-pipe, B the oil-pipe, Cibe injector, D the swivel upon which the injector is hung so that gases which contain less methane contain all the more hydrogen, it may be swung clear of the furnace, E the fire-door, and F the viz. 2.9 to 29.8%. There is also some ethylene, ethane and handie for adjusting the injector. In fig. 10, which represents a section of the furnace, H is a fire-brick pier and K a fire-brick of incombustible gases-oxygen, carbon dioxide, nitrogen

carbon monoxide, rarely exceeding 2 or 3%. The quantity ba Jing bridge.

It is found in practice that to leave out the fire-bars ordinarily ranges from mere traces to about 5%. The density is from used for coal produces a better result with liquid fuel than the 0.45 to 0.55. The heating power of 1000 cub. ft. of natural gas alternative system of keeping them in place and protecting them is equal to from 80 to 120 lb, on the average 100 tb, of good by a laver of broken fire-brick.

Bcilers fitted upon all the above systems have been run for coal, but it is really worth much more than this proportion thousands of miles without trouble. In new construction it is would indicate, as it burns completely, without smoke or ashes, desirable to give larger combustion chambers and longer and narrower and without requiring any manual labour. It is employed for boiler tubes than in the case of boilers intended for the combustion all domestic and for most industrial purposes. di coal alone.

(F. F.") Gaseous Fuel.

The origin of natural gas is not properly understood, even

now. The most natural assumption is, of course, that its formaStrictly speaking, much, and sometimes even most, of the tion is connected with that of the petroleum always found in beating effected by solid or liquid fuel is actually performed by the same neighbourhood, the latter principally consisting of the the gzjes given off during the combustion. We speak, however, higher-boiling aliphatic hydrocarbons of the methane series. o rascous fuel only in those cases where we supply a combustible But whence do they both come? Some bring them into congas from the outset, or where we produce from ordinary solid nexion with the formation of coal, others with the decomposition or liquid) fuel in one place a stream of combustible gas which of 'animal remains, others with that of dialomaccae, &c., and is formed in another place, more or less distant from that where even an inorganic origin of both petroleum and natural gas has it has been generated.

been assumed by chemists of the rank of D. I. Mendeléeff and The various descriptions of gaseous fuel employed in practice H. Moissan. may be classified under the following heads:

II. Gases oblained as By-products. There are two important 1. Natural Gas.

cases in which gaseous by-products are utilized as fuel; both II. Combustible Gases obtained as by-products, in various technical operations.

are intimately connected with the manufacture of iron, but in III. Coal Gas (Illuminating Gas).

a very different way, and the gases are of very different IV. Combustible Gases obtained by the partial combustion of composition. coal, &c.

(@) Blast-furnace Gases.-The gases issuing from the mouths I. Natural Gas.-From time immemorial it has been known of blast-furnaces (see IRON AND STEEL) were first utilized in that in some parts of the Caucasus and of China large quantities 1837 by Faber du Faur, at Wasseralfingen. Their use became of gases issue from the soil, sometimes under water, which can more extensive after 1860, and practically universal after 1870. be Lghted and burn with a luminous flame. The eternal The volume of gas given off per ton of iron made is about 158,000 fires" of Baku belong to this class. In coal-mines frequently cub. ft. Its percentage composition by volume is: sizlar strearms of gas issue from the coal; these are called Carbon monoxide 21.6 to 29.0, mostly about 26 * blowers," and when they are of somewhat regular occurrence Hydrogen

1.8 are sometimes conducted away in pipes and used for underground



Carbon dioxide ligting. As a regular source of heating power, however, natural


60, pas is employed only in some parts of the United States, especially Steam


5 % in Pennsylvania, Kansas, Ohio and West Virginia, where it a'rays occurs in the neighbourhood of coal and petroleum

100% Edds. The first public mention of it was made in 1775, but it was I There is always a large amount of mechanically suspended



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fue-dust in this gas. It is practically equal to a poor producer- | it is obtained by heating bituminous coal in fireclay retorts and gas (see below), and is everywhere used, first for heating the blast purifying the products of this destructive distillation by cooling, in Cowper stoves or similar apparatus, and secondly for raising washing and other operations. The residual gas, the ordinary all the steam required for the operation of the blast-furnace, composition of which is given in the table below, amounts to that is, for driving the blowing-engines, hoisting the materials, about 10,000 cub. ft. for.a ton of coal, and represents about &c. Where the iron ore is roasted previously to being fed into 21% of its original heating value, 56.5% being left in the coke, the furnace, this can also be done by this gas, but in some cases 5.5% in the tar and 17% being lost. As we must deduct from the waste in using it is so great that there is not enough left for the coke that quantity which is required for the heating of the the last purpose. The calorific power of this gas per cubic foot retorts, and which, even when good gas producers are employed, is from 80 to 120 B.Th.U.

amounts to 12% of the weight of the coal, or 10% of its heat Since about 1900 a great advance has been made in this field. value, the total loss of heat rises to 27%. Taking, further, into Instead of burning the blast-furnace gas under steam boilers account the cost of labour, the wear and tear, and the capital and employing the steam for producing mechanical energy, the interest on the plant, coal gas must always be an expensive fuel gas is directly burned in gas-motors on the explosion principle. in comparison with coal itself, and cannot be thought of as a Thus upwards of three times the mechanical energy is obtained general substitute for the latter. But in many cases the greater in comparison with the indirect way through the steam boiler. expense of the coal gas is more than compensated by its easy After all the power required for the operations of the blast-distribution, the facility and cleanliness of its application, the furnace has been supplied, there is a surplus of from 10 to general freedom from the mechanical loss, unavoidable in the 20 h.p. for each ton of pig-iron made, which may be applied case of coal fires, the prevention of black smoke and so forth. to any other purpose.

The following table shows the average composition of coal gas (6) Coke-oven Gases.—Where the coking of coal is performed by volume and weight, together with the heat developed by in the old beehive ovens or similar apparatus the gas issuing its single constituents, the latter being expressed in kilogramat the mouth of the ovens is lost. The attempts at utilizing the calories per cub. metre (0-252 kilogram-calories= 1 British heat gases in such cases have not been very successful. It is quite i unit; 1 cub. metre=

35.3 cub. ft; therefore 0·1123 calories per different where coke is manufactured in the same way as illumin-1 cub. metre=1 British beat unit per cub, foot). ating gas, viz. by the destructive distillation of coal in closed apparatus

Heat-value Heat-value (retorts), heated from the outside.


Heat-value Constituents.


per Quantity This industry, which is described in


per cent. contained in

Calories. detail in G. Lunge's Coal-Tar and

of Total

1 Cub. Met. Ammonia (4th ed., 1909), origin- Hydrogen, H,



22.8 ated in France, but has spread far Methane, CH


54.5 more in Germany, where more than Carbon monoxide, CO


Benzene vapour, CH,
half of the coke produced is made

7.4 33,815


7.7 Ethylene, C,H,



530 by it; in the United Kingdom and the

9.9 Carbon dioxide, co, :

2.5 United States its progress has been Nitrogen, N,

5.5 much slower, but there also it has long been recognized as the only proper Total

5319 method. The output of coke is increased by about 15% in comparison with the beehive ovens, One cubic metre of such gas, weighs 568 grammes. Rich gas, as the heat required for the process of distillation is not produced or gas made by the destructive distillation of certain bituminous by burning part of the coal itself (as in the beehive ovens), but schists, of oil, &c., contains much more of the heavy hydrocarbons, by burning part of the gas. The quality of the coke for iron and its heat-value is therefore much higher than the above. making is quite as good as that of beehive coke, although it The carburetted water gas, very generally made in America, and differs from it in appearance. Moreover, the gases can be made sometimes employed in England for mixing with coal gas, is to yield their ammonia, their tar, and even their benzene vapours, of varying composition; its heat-value is generally rather less the value of which products sometimes exceeds that of the coke than that of coal gas (see below). itself. And after all this there is still an excess of gas available IV. Combustible Gases produced by the Partial Combustion of for any other purpose.

Coal, &c.—These form by far the most important kind of gaseous As the principle of distilling the coal is just the same, whether fuel. When coal is submitted to destructive distillation to the object is the manufacture of coal gas proper or of coke as the produce the illuminating gas described in the preceding paramain product, although there is much difference in the details graph, only a comparatively small proportion of the heating of the manufacture, it follows that the quality of the gas is very value of the coal (say, a sixth or at most a fifth part) is obtained similar in both cases, so far as its heating value is concerned. in the shape of gaseous fuel, by far the greater proportion remainOf course this heating value is less where the benzene has been ing behind in the shape of coke. extracted from coke-oven gas, since this compound is the richest An entirely different class of gaseous fuels comprises those heat-producer in the gas. This is, however, of minor importance produced by the incomplete combustion of the total carbon in the present case, as there is only about 1% benzene in these contained in the raw material, where the result is a mixture of gases.

gases which, being capable of combining with more oxygen, can The composition of coke-oven gases, after the extraction of be burnt and employed for heating purposes. Apart from some the ammonia and tar, is about 53% hydrogen, 36% methane, descriptions of waste gases belonging to this class (of which the 6% carbon monoxide, 2 lo ethylene and benzene, 0.5% sul- most notable are those from blast-furnaces), we must distinguish phuretted hydrogen, 1.5% carbon dioxide, 1% nitrogen. two ways of producing such gaseous suels entirely different in

III. Coal Gas (Illuminaling Gas). -Although ordinary coal gas principle, though sometimes combined in one operation. The is primarily manufactured for illuminating purposes, it is also incomplete combustion of carbon may be brought about by extensively used for cooking, frequently also for heating domestic means of atmospheric oxygen, by means of water, or by a rooms, baths, &c., and to some extent also for industrial opera- simultaneous combination of these two actions. In the first tions on a small scale, where cleanliness and exact regulation of case the chemical reaction is the work are of particular importance. In chemical laboratories


(@); it is preferred to every other kind of fuel wherever it is available. the nitrogen accompanying the oxygen in the atmospheric air The manufacture of coal gas being described elsewhere in this necessarily remains mixed with carbon monoxide, and the resultwork (see Gas, & Manufacture), we need here only point out that I ing gases, which always contain some carbon dioxide, some






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