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Copyright infringement liability can be quite severe. 32° »» •00000235 The expansion of a long bar of metal is considerable. .78*9 4-88 10-34 1-38 no 34 127 Staffordshire Coal . .' 78*2 5-28 1032 1-50 r20 3'5 1-28 Yorkshire Coal 78-1 4-84 io*53 I '43 no 4-0 1-29! Its average composition is '82 carbon and *I2 ash; its heating power is '82 x 14500 = II 890; its evaporative power is 11890-5-966= 12*31 pounds of water from and at 2x2^ Fahr. 1560 1420 1340 1260 1 190 970 580 The quantity of ash yielded by wood averages from i to 4 per cent. The heating power of ordinary coal-gas is from 630 to 700 heat-units per cubic foot of gas. The heating power of water-gas being one-half that of coal-gas is = 630 .4-2 = 315 heat-units per cubic foot of gas. 3 1 The temperature produced by the flame from a properly proportioned mixture of coal-gas and air is about 3670° Fahr., and that of water-gas is about 4900® Fahr. Its calorific power is from two and a half to three times as great as that of coal. — Atomic Weight of the Prinxipal Elementary Con- stituents OF Fuel. Carbonic acid is a compound of one atom of carbon with two atoms of oxygen ; carbonic oxide is composed of the same quantity of carbon with only half the above quantity of oxygen, but it has the same volume as carbonic acid. .10 13 3^ The direct effect of the union of carbon and oxygen is the formation of carbonic acid.
Maintain attribution The Google "watermark" you see on each file is essential for informing people about this project and helping them find additional materials through Google Book Search. Keep it legal Whatever your use, remember that you are responsible for ensuring that what you are doing is legal. In a test of a boiler fired with, peat the evaporation was only 4-2 pounds of water per pound of peat. 275 1209 2916 nil 55II 5-3 1048 1048 I 1527 1286 2813 27 611 1 I II6I 309 1470 I- Heating Power of Oaeeous-Fnelfl. Uqiiid-Fne L — Dquid-fuel gives special facilities for the development and maintenance of intense steady heat, for the quick control of the applied heat, and for the rapid generation of steam. Urquhart's locomotives is 14 pounds of water per pound of fuel. This shows that the combustion is very complete, and that the apparatus for effecting the combustion of the fuel is practically perfect. composition, and has a less evaporative value than petroleum. The quantity of oxygen required for the saturation of the two con- stituents of coal-gas to effect perfect combustion, is determined by their chemical constituents.
Do not assume that just because we believe a book is in the public domain for users in the United States, that the work is also in the public domain for users in other countries. 82-4 5'3o 8-30 r2o 70 2-1 1-30 Australian Brown Coal . Peat is frequently compressed into blocks weighing about 70 lbs. — It will be seen from the above Table that the heating power of water-gas is only about one-half that of coal- gas, and that of generator-water-gas is only about one-half that of water-gas. Liquid-fuels, such as petroleum, petroleum-refuse, tar, and creosote-oil or tar-refuse, have a much higher calorific power than coal, because they contain a much larger quantity of hydrogen. •938 86-6 : 12-3 I'l Petroleum-refuse •938 87*1 117 1-2 Good English coal, mean of 98 samples 1380 8o-o 5-0 8-0 Theoretical Evapora- ; tion in pounds of water ■ Heating per pound of fuel , Siwdlic Gravity «t 3.' Fi Jir. The theoretical evaporative value of this fuel is 17*1 lbs. of fuel ; the actual efiiciency of petro- leum-refuse is therefore =14 lbs. Urquhart's Spray-Zi^jector for Liqnid-Fne L — Urquhart's spray- injector is shown in Fig. It is placed outside the fire-box, and its nozzle is connected to the fire-box by a tube in the water-space. The regenerative or accumulative combustion-chamber used by Mr. The composition of creosote is from 78 to 82-5 of carbon, 6 to 10 of hydrogen, and 75 to 16 of oxygen. It dilutes the products of combus- 36 STEAM-BOILER CONSTRUCTION. The quantity of atmospheric air required to supply the oxygen is found from the proportion which oxygen bears in volume to that of the air, five volumes of the latter being required to produce one volume of the former, and as two volumes of oxygen are required for each volume of coal-gas, ten volumes of air are required to produce these two volumes.
This coal is difficult to ignite, bums slowly or sluggishly, and breaks into small pieces when rapidly heated, but yields intense heat without smoke when dry. Anthracene, -46 pound ; alizarin, 20 per cent., 2*25 pounds. Ugnite, or Brown Coaly is of more recent formation than bituminous coal, and is an imperfectly formed coal. In the test of the boiler of a simple portable engine with a similar fire-box, the straw burnt per square foot of fire-grate per hour was 57*6 pounds ; the straw consumed per indicated horse-power per hour was 11 '9 pounds, and each pound of straw evaporated 2^ pounds of water. With a supply of unvitiated atmospheric air containing 20 per cent, of oxygen, 10 cubic feet of air are required to supply 2 cubic feet of oxygen to effect the combustion of i cubic foot of coal-gas. Carbon in burning produces carbonic acid, composed of 75 -f- (75 200) == -273 lb. of oxygen per pound of air, = 11*96 lbs., or say 12 lbs. The weight of a cubic foot of air at the standard temperature, 62° Fahr. ; hence one pound of hydrogen requires 35*87 -7- "076098 = 471*44, or say 472, cubic feet of air; and one pound of carbon requires 11*96 -5- 076098 = 157*16, or say 158, cubic feet of air for combustion. Average of 24 Samples Welsh Steam-Coal of Medium Quality, Averages Newcastle Steam-Coal Average of 18 Samples Ditto, of Good Quality . Averages Lancashire Steam-Coal Average of 24 Samples Derbyshire Steam-Coal . „ 18 „ ' Yorkshire Steam-Coal „ 12,, : Steam-Coal, English, Average of a large number of I Samples 1 Slack, Good Clean Rough, English . A thick fire is necessary for the production of a high temperature ; the more freely the coals bum the thicker may the fire be.
It requires a very large fire-grate, or about double the grate-area required for bituminous coal, and heavy charges of coal at each firing. It is frequently of a woody texture, and generally contains considerable moisture and a large propor- tion of oxygen. It weighs less and develops less heat than coal, and is not a valuable description of fuel. Large-sized screenings are termed rough slack, and small-sized screenings small slack. For ordinary portable engine-boilers three pounds of straw may be assumed to be equivalent in heating power to one pound of coal when burnt in a furnace of this kind. — Green wood contains about 50 per cent, of moisture, and loses about 50 per cent, in weight when dried at a temperature of 280** Fahr. In its ordinary state of dryness, or contain in|^ so per cent, of water. It is necessary to provide the air in such a manner as to ensure a pure supply without deficiency of oxygen. of oxygen from the air to support the combustion of the hydrogen, 8 lbs. This is the minimum theoretical quantity chemically consumed by each combustible, and the weight of air in lbs., W, theoretically required for the combustion of any kind of fuel, may be found according to the above data by the following formula: — oxygen n\ W = (12 X % carbon) (36 X [7o hydrogen Example : What quantity of air is theoretically required for the com- bustion of coal containing *8 carbon, *o5 hydrogen, and -08 oxygen? Coals which develop little flame, and small coals of all kinds, bum best in a thin fire.
— The force exerted by a bar in expanding by heat, or in contracting by cold, may be found by the following formula : — Let A = the sectional area of the bar in square inches. Anthracite 35 46 60 70 93 5*1 5-3 5-4 \i 57 \i 59-9 487 37*6 34-5 24-4 19-3 12*8 32 The transformation of the vegetable matter to coal is, briefly, as follows : — When wood and vegetable matter are buried in the earth, exposed to moisture, and partially or entirely excluded from the air, they decompose slowly and evolve carbonic acid gas, thus parting with a portion of their original oxygen. The gaseous contents of the coal— carbonic acid, carburetted hydrogen, nitrogen, and olefiant gas — are continually escaping, and the disengagement of the gases gradually transforms bituminous or' ordinary coal into anthracite or hard coal. the wood is converted into a strong, brittle, black charcoal of wood-like structure, which makes a bright, clear fire that radiates heat strongly, and bums without flame or smoke. Compressed Charooal is composed of t^-o-thirds of powdered charcoal and one-third gas-tar* It is moulded under pressure into short round pieces, and baked at a high temperature. Patent Fuelt or artificial fuel, is composed of small coal, or other refuse fuel, mixed with adhesive and combustible substances, such as pitch and tar, and moulded by machinery into blocks. Hydrogen ,, 4'25 »» 5*6 Oxygen „ i „ 2 Nitrogen „ i „ r8 Sulphur „ I „ 1*6 „ Ash „ 3 " S'o It bums freely, and develops on an average 9,660 units of heat per pound. 25-00 4-50 3000 075 1-50 loo-o loo-oo Hard woods 3deld more intense, more prolonged, and steadier, heat than soft woods. Tllmni Tiatiiig Oas, or coal-gas, is the product of the distillation of coal in closed retorts. Its actual evaporative power in practice is from 15I to 17 pounds of water, from and at 212® Fahr., per pound of oil. In a general way, 104 gallons, or 104 x 8*i8 =851 pounds, of this oil are equal in evaporative power to one ton of good coal. Xttthod of Burning Fu«Mi L — Petroleum fuel-oil is burnt, in a boiler furnace, in the form of spray, after being pulverised or atomised by steam or compressed air. If the carbonaceous constituent of coal while at a high temperature en- counters carbonic acid, this latter, taking up an additional portion of carbon, is converted into carbonic oxide and again becomes a gaseous and invisible combustible. Averages Wood-Chips and Green Twigs, in a damp state, or containing 50 7o of moisture . Average Calorific Power, or Units of Heat deve- loped per Pound of Fuel.
C = the coefficient of expansion from the above Table. By this means they become gradually converted into lignite or brown coal, which contains a larger proportion of hydrogen than wood does. The composition of the fossil vegetable matter at different stages of transformation to coal is given approximately in Table 9, in which earthy matter is not included. By using forced draught with a small supply of air to the fire, intense heat may be developed by the combustion of charcoal. Coalrdiist Briquettes, or block-coal, of good quality, generally contain from 86 to 90 per cent, of coal-dust, mixed with from 8 to 10 per cent, of pitch, and from 2 to 4 per cent, of ta^. This is equal to an evaporation of 9660 -4- 966 = 10 pounds of water per pound of fuel, from and at ^12° Fahr. Soft woods kindle more readily, and burn more rapidly, than hard woods. The quantity of gas produced is generally io,cx)0 cubic feet per ton of coal distilled. It cannot be burned in an ordinary furnace as arranged for coal-buming, because it makes an enormous quantity of smoke, which coats the water-heating surfaces with a sticky, sooty, non-conducting deposit. The most prevailing operation of the furnace, however, and by which the largest quantity of carbon is lost in the shape of carbonic oxide is the following : — The air, on entering from the ash-pit, gives out its oxygen to the glowing carbon on the fire-grate, and generates much heat in the formation of carbonic acid. (Despretz) Calorific Power, pr Uniu of Heat deve- loped per Pound of Fuel. 12906 13500 13208 "339 11592 104 1 1 8694 7844 9660 9500 7245 7516 7245 6888 6610 6536 6482 6436 6400 4830 6347 6279 4830 3024 5912 5217 3961 5000 4916 4478 4325 4453 2495 4682 4032 4106 3980 3864 2898 3671 1932 Evapora- tive Power In lbs.
This is a digital copy of a book that was preserved for generations on library shelves before it was carefully scanned by Google as part of a project to make the world's books discoverable online. 1 52-2 3630 3-86 2-27 4-55 •78 99*94 Newcastle Coal 6o'4 26-64 3'25 1-67 7-00 •84 99-80 T^ancashire Coal 487 35-56 6-34 154 6-83 •69 99*66 Derbyshire Coal 42-5 40-00 787 1-37 7-46 76 9996 Staffordshire Coal . 2X cent, of the heat developed by the combustion of the coal. of water at 55° Fahr., raised its temperature to 118° Fahr., then the rise of temperature is =1x8° -55° =63°. The fire-bars should be of wrought-iron, and the fire-grate protected from burning by water-pans placed in the ash-pit. For instance, an atom of hydrogen is double the volume of an atom of carbon- vapour, but the latter is six times the weight of the former. The difference between the total heat evolved and that available for work is due principally to the following sources of loss, viz. This has been very nearly attained with quadruple expansion engines, which, in some cases, develop one indicated horse-power with a combustion of 1 1 lb. In the most economical modern engines the consumption of coal per in- dicated horse-power per hour, under ordinary woiking conditions, averages as follows : — lbs. The efficiency is, ^ 5210-1013 ^.3 5210 that is, the heat realised is only 80 per cent, of that supplied, showing a loss of 20 per cent, of the heat evolved. The temperature of the fumace of a steam-boiler may be determined approximately by melting a piece of metal, of known melting point, in the fire. Wrought-iron begins to melt at Mild-steel boiler-plates .
It has survived long enough for the copyright to expire and the book to enter the public domain. 56-4 26-61 6-37 1-76 7-91 •87 9992 Yorkshire Coal , 62-0 20-40 573 2-i8 8-40 •89 99*60 Scotch Coal . It may be roughly estimated from the rise of temperature observed in quenching a known weight of clinker and ash in a known weight of water. Breose from coke of good quality will develop from 6,279 ^o 7,245 units of heat per pound, and its evaporative power is from 6| to 7^ pounds of water per pound of breeze, from and at 212^ Fahr. An atom of hydrogen is double the volume of an atom of oxygen, but the latter is eight times the weight of the former. : — Initial-heating of the fuel and air for combustion. The Tamperatnre of the Fnxnaoo of a Stoftm-Boilor with HTatnral Ihnraght may be calculated in a similar way to the above. of good coal btiming to carbonic acid, supported by oxygen supplied by 24 lbs. of air produces 25 pounds of gases, and the absolute temperature of the air is = 461 -f 62 = 523^ Fahr. The melting points of metals are given in the following Table : — Table 22. Meta L Melts at Fahrenheit Metal ' Melts at Fahrenheit.
Nevertheless, this work is expensive, so in order to keep providing this resource, we have taken steps to prevent abuse by commercial parties, including placing technical restrictions on automated querying. Good Welsh steam coal only yields yz per cent, of ash. Coals which produce much clinker rapidly destroy the fire-grate bars. 1 2 per cent- 6 to 18 per cent- Small slack of inferior quantity seldom produces less than 20 per cent, of clinker and ash in the furnace of a steam-boiler. Hydrogen 4 „ 6 „ Oxygen 25 „ 45 » Nitrogen i „ if » Ash 4 » 7 » Peat is consumed so rapidly as to necessitate almost constant firing. Thomas Urquhart, Locomotive Superintendent, Grazi Tsaritsin Railway, South- East Russia. In a general way, a boiler fired with this oil may be from one-third to one- fourth smaller than one fired with coal, and still possess the same evaporative power, with the same strength of draught. Two atoms of nitrogen, or 175 x 2 = 350 lbs., combining with one atom, or 100 lbs., of oxygen, form 350 -h 100 ^ 450 lbs. The igniting temperatures of good coal from different districts generally average as follows : — • Fahr. In the Comlnuition of Coal the bituminous portion is convertible to the purposes of heat in the gaseous state only, and the carbonaceous portion is combustible only in the solid state ; neither can be consumed while they remain united. of air per pound of coal at a temperature of 62® Fahr., may be found as follows : — I lb. Assuming that by well- arranged absorbing or heating-surfaces of the boiler and feed-water heater the gases enter the chimney at 400® -|- 461° = 861® Fahr. Then the temperature of the furnace resulting from combustion is, ^_i43oo units of heat ^ o ^ ^86° Fahr. Or it may be put in this form : — The quantity of the heat required to raise the contents of the furnace of a steam-boiler one degree in temperature for each pound of coal consumed is = I lb. above that of the atmosphere, or with air at 62° = 62° -f- 2477^ = 2539*^ Fahr.
We also ask that you: Make non-commercial use of the files We designed Google Book Search for use by individuals, and we request that you use these files for personal, non-commercial purposes. The quantity of clinker and ashes produced from coal consumed in the furnace of a steam-boiler is, under ordinar}' working conditions, seldom less than 10 per cent. The expense of getting rid of clinker and ash is so considerable that it is • frequently more economical to use best steam-coal yielding little ash, than a cheaper coal making a quantity of clinker and ash. The Heating Power of Peat in a moderately dry state, containing •47 carbon, '05 hydrogen, and '32 oxygen, is as follows : — The constituent oxygen will combine with '32 -4- 8 = '04 hydrogen, leaving '05 — -04 = -oi hydrogen in excess, and carbon '47 x 14500 = 6815 units -f ('Oi x 62535) COMPOSITION AND HEATING-POWER OF CHARCOAL. Petrdlenni-Sefiuie or Asta M is the dead oil or refuse left in the stills after the crude oil has been refined. A system of burning this and other liquid fuels has been devised and brought to great perfection by Mr. The com- position, heating-power, and evaporative power of different kinds of liquid fuel used on his locomotives are given in Table 1 7. The processes incident to the combustion of these two portions will now be considered separately in order to simplify the explanation. This is equal to an absolute temperature of 2539 -f 461° = 3000° Fahr. As pyrometers are seldom reliable, the temperature of the furnace of a steam-boiler cannot accurately be ascertained, but it may be determined approximately in three different ways, viz :— By the heat imparted to a piece of iron embedded in the glowing fuel : by melting a piece of metal of known melting point in the fire : by the colour of the fire.
17 = 18000CXX) for cast-iron J 38020000 for wrought-iron ; and 30000000 for mild-steel. Classes of Coa L — ^There are two classes of coal, — anthracite and bituminous. Charcoal of hard wood is composed approximately as given in the following Table : — Table 13. This is equal to an evaporation of 8970 ■ - 966 = 9*28 pounds of water per pound of fuel, from and. Sawdust Briquettes, or block sawdust, are a mixture of sawdust, tar, and clay moulded into blocks. A Cord of Wood contains 4x4x8 = 1 28 cubic feet, of which 73 cubic feet are solid wood, and the remainder, 55 cubic feet, is space. Water-Oas is formed by the combustion of carbon in aqueous vapour or steam. When the oil is sprayed into a furnace of this kind, practically complete combustion may generally be obtained without the production of soot. — ^The quantity of air required for the complete combustion of fuel-oil is at least one-third greater than that required for good coal. Thus, by the- conversion of one volume of acid into two volumes of oxide, heat is absorbed! Averages I Gas-Coke, good Average of a number of Samples Breeze from Gas- Coke, good . 2174 20'86 19-87 18-37 20-65 20-37 20-22 20-19 9-65 9-50 9*39 9-19 8-95 875 8-6o 8-50 8-00 5-00 7-56 7-i8 6-42 574 5'53 5*47 5'30 3'90 4-66 4-50 4*45 4*36 4-24 4-00 376 3'9' Carbonic Oxide burning to Carbonic Acid (Dulong) Ditto, ditto (Favre and Silbermann) Carbon burning to Carbonic Oxide „ „ Ditto, ditto . — ^The full value of the heating-power of the fuels given in the foregoing Table is not realised in practice, in the evaporation of water to steam, owing to losses from various causes, but principally by conduction, radiation, and imperfect combustion, and a portion of the heat is necessarily expended in creating a draught in: the chimney. Then -— -,r— = '^7 P^r cent., showing that the actual evaporation is 13 per cent, less than the theoretical evaporation. — ^The fire should be maintained at as great a heat as possible.Tags: Adult Dating, affair dating, sex dating