Part 21 (1/2)
+----------------------+-------+--------+-------+ |Substance |Carbon |Hydrogen|Oxygen | +----------------------+-------+--------+-------+ |Wood Fiber | 5265 | 525 | 4210 | |Peat | 5957 | 596 | 3447 | |Lignite | 6604 | 527 | 2869 | |Earthy Brown Coal | 7318 | 568 | 2114 | |Bituminous Coal | 7506 | 584 | 1910 | |Semi-bituminous Coal | 8929 | 505 | 566 | |Anthracite Coal | 9158 | 396 | 446 | +----------------------+-------+--------+-------+
Composition of Coal--The uncombined carbon in coal is known as fixed carbon Soen and this, together with other gaseous substances driven off by the application of heat, form that portion of the coal known as volatile matter The fixed carbon and the volatile en contained in the volatile matter are not combustible, but custom has applied this term to that portion of the coal which is dry and free froen
The other i into the composition of coal are moisture and the refractory earths which form the ash The ash varies in different coals from 3 to 30 per cent and the ht of the coal, depending upon the grade and the locality in which it is e of ash is undesirable as it not only reduces the calorific value of the fuel, but chokes up the air passages in the furnace and through the fuel bed, thus preventing the rapid coh efficiency If the coal contains an excessive quantity of sulphur, trouble will result from its harmful action on the metal of the boiler where moisture is present, and because it unites with the ash to forrate bars and fore quantities of unconsumed carbon may be imbedded
Moisture in coalthe temperature of a furnace, as it is non-co evaporated and superheated to the teases In some instances, however, a certain amount of moisture in a bituminous coal produces a mechanical action that assists in the coher capacities than with dry coal
Classification of Coal--Custo content of carbon and volatile ives the approxieneral classes of coals with the corresponding heat values per pound of combustible
TABLE 36
APPROXIMATE COMPOSITION AND CALORIFIC VALUE OF GENERAL GRADES OF COAL ON BASIS OF COMBUSTIBLE
+-------------------+----------------------------+--------------+ | Kind of Coal | Per Cent of Combustible | B t u | | +------------+---------------+ Per Pound of | | |Fixed Carbon|Volatile Matter| Combustible | +-------------------+------------+---------------+--------------+ |Anthracite |970 to 925| 30 to 75 |14600 to 14800| |Semi-anthracite |925 to 875| 75 to 125 |14700 to 15500| |Semi-bituminous |875 to 750| 125 to 250 |15500 to 16000| |Bituminous--Eastern|750 to 600| 250 to 400 |14800 to 15300| |Bituminous--Western|650 to 500| 350 to 500 |13500 to 14800| |Lignite | Under 50 | Over 50 |11000 to 13500| +-------------------+------------+---------------+--------------+
Anthracite--The name anthracite, or hard coal, is applied to those dry coals containing from 3 to 7 per cent volatile matter and which do not shen burned True anthracite is hard, compact, lustrous and sometimes iridescent, and is characterized by few joints and clefts Its specific gravity varies fro, it kindles slowly and with difficulty, is hard to keep alight, and burns with a short, almost colorless flame, without smoke
Semi-anthracite coal has less density, hardness and luster than true anthracite, and can be distinguished from it by the fact that when newly fractured it will soot the hands Its specific gravity is ordinarily about 14 It kindles quite readily and burns more freely than the true anthracites
Semi-bituminous coal is softer than anthracite, contains more volatile hydrocarbons, kindles more easily and burns h calorific value and is of the highest order for stea purposes
Bituminous coals are still softer than those described and contain still more volatile hydrocarbons The difference between the semi-bituminous and the bituminous coals is an i value per pound of coher than the latter, and they burn with much less smoke in ordinary furnaces The distinctive characteristic of the bituminous coals is the e In color they range fro a resinous luster in the most compact specimens, and a silky luster in such speciravity is ordinarily about 13
Bitu class The former, when heated, fuse and swell in size; the latter burn freely, do not fuse, and are co coals are rich in volatile hydrocarbons and are valuable in gas manufacture
Bituminous coals absorb moisture from the atmosphere The surface , but a portion of the water can be re the coal to a terees Fahrenheit
Cannel coal is a variety of bituen and hydrocarbons, and is exceedingly valuable as a gas coal It has a dull resinous luster and burns with a bright fla Cannel coal is seldoh it is sometimes mixed with seh rates of combustion is desired The composition of cannel coal is approximately as follows: fixed carbon, 26 to 55 per cent; volatile matter, 42 to 64 per cent; earthy ravity is approxianic es of its conversion into coal, and includes all varieties which are intermediate between peat and coal of the older for 12 to 123, and when freshly h as 50 per cent ofa distinctly woody structure, in the poorer varieties, to a black, with a pitchy luster rese and burns with a bright but slightly smoky flame with moderate heat It is easily broken, will not standin transportation, and if exposed to the weather will rapidly disintegrate, which will increase the difficulty of burning it
Its composition varies over wide lih as 50 per cent Its high content of e quantity of air necessary for its corade fuel and is used almost entirely in the districts where anic es of its conversion into coal and is found in bogs and sih, averaging 75 or 80 per cent It is unsuitable for fuel until dried and even then will contain as much as 30 per cent moisture Its ash content when dry varies froe deposits of peat have been found, it has not as yet been found practicable to utilize it for stea purposes in competition with coal In some European countries, however, the peat industry is common
Distribution--The anthracite coals are, with some unimportant exceptions, confined to five s list These fields are given in the order of their hardness
Lehigh or Eastern Middle Field Green Mountain District Black Creek District Hazelton District Beaver Meadow District Panther Creek District[33]
Mahanoy or Western Field[34]
East Mahanoy District West Mahanoy District
Wyo or Northern Field Carbondale District Scranton District Pittston District Wilkesbarre District Plymouth District