AUGUST 8, 1001. 



The Weekly Florists' Review* 



293 



In the case of anthracite coal, the 

 suits will be secured when there^ is 

 Are and sufficient air is 

 every particle of carbon 

 contact with tree oxygen. , ,^ , ■ , 



It is known that about one-fourth of a neat 

 unit (.2375), is required to raise a pound of 

 air one degree Fahrenheit or, if the openings 

 through the grate admitted twice the amount 

 of air needed for perfect combustion, it would 

 require not far from l.£ 

 this ext 



jnits to rai 

 the temperature of the chii 



by the combustion of 



and 



naturally 



furnish as 



of coal 

 10 per cent 

 a pound of 



This appai 



that coal, ; . , 



tains a considerable amount of hydrogen, 

 united with carbon, forming what is called 

 hydrocarbon, which will burn after being 

 brought into a gaseous form. 



The combustion of hydrogen generates an 



erated by the burning of one pound. When 

 bituminous coal Is burned, it is of especial 

 importance that there should be no great sur- 

 plus in the amount of air, as a serious loss 

 would otherwise be caused. Thus, if 24 pounds 

 of air are supplied for each pound of carbon 

 burned, the gas will have a temperature or 

 but 1.300 degrees and at this temperature the 

 carbon will not ignite, and 

 tides of 



win for 



the fir 



ned 



fill 



boiler tube 



and all exposed portions of the boiler, a: 

 should be guarded against by the use o 

 walls of brick and other coverings. 



The amount of air can be regulated I 

 by the ash-pit doers and by the depth 

 With a good depth of coal over the grat 

 the movement of the air will be check; 

 becoming warmed, it will have a mu( 

 cooling effect on the temperature of th( 

 of combu 



!ie temperature of the gases 



There Is also a large amoimt of heat 



that passes out through the chimney. This 

 cannot be spoken of as lost, as it is necessary 

 to produce a draught and 

 feet combustion of the fui 

 The loss will be greate 

 of air furnished is in ex 

 required for the maximun 

 with only 12 pounds " " 





of the 



but 



ught ■ 



eighths going to produce steam: with 24 pound 

 of air, one-fourth of the heat will be losi 

 while with 4S pounds of air for each pound o 

 carbon burned the loss of heat up the chlmne 

 will be one-half that given off by the coal. 



Wood as Fuel. 



The fuel first used, and the one that for 

 long time was the only one available, wa 

 wood or wood charcoal, but for some year 

 other materials have taken Its place excep 

 in few localities. In sections remote from cos 

 fields and where large areas of forest ai 

 found, wood is even now used to a conslderab] 

 extent in the production of steam for green 

 house heating and other purposes. 



The average wood used 

 from 25 to 6_0 per cent c 

 proportion being 



ater, the larger 

 freshly cut, and 

 from 30 to 50 per cent of carbon. In the process 

 of combustion the water is first evaporated, 

 requiring a large amount of heat, the gaseous 

 portion is then driven oft and the oxidation 

 of the carbon follows. Hickory, white oak, 

 hard maple and beech are among the more 

 valuable woods for fuel purposes. The com- 

 bustible value of white pine, elm and the more 

 common soft woods. Is from one-half to two- 

 thirds that of hard maple. 



Petroleum. 



■In some sections considerable attention has 

 been paid to the use of crude oil as a fuel for 

 greenhouse heating. 



With oil of a specific gravity of 0.875. and 

 costing 3 cents per gallon, or $1.26 per barrel 



1,000 pounds of water. If the sp. g. is de- 

 creased to 0.775 and the price remains the 



pounds 

 B. - ■ 

 will 



U. and 



14 



tor fuel 

 rlU be 34 cents, 

 ng 10,000 B. T. U. wo 

 ;t 15 cents to evaoorati 

 If the coal shows 

 $2.50 per 



flgu 



of oil as fuel Is about 

 coal, but considerable allowance should '-e 

 made for the saving In labor In firing and re- 

 moving ashes where oil is used. 



At the present price of crude oil, its cost 

 as fuel Is more than double that of good 

 steam coal, as was shown by the reports made 

 to the writer from florists having about the 



Natural Gas. 



Natural gas also takes a high place as a fuel 

 for steam making, as it is very effectual. 



the pressu 



of coal (12,000 B. T. U.) 



double their va: 

 that the above 



aalyses show 

 iminous coal. 



heating purposes from 10 to 15 cents 

 pared with coal the actual value 

 is considerably increased by the 



The heating value 



600.000 to 900.000 B. T. U., 



Coal. 



That the coal used as fuel Is merely fossil- 

 ized vegetation is shown by the fact that we 

 find It in all forms from peat to anthracite 

 coal, varying in proportion to the extent to 

 which the distillation of the woody fiber has 

 been carried. Aside from peat and lignite, 

 which are but slightly fossilized. We have 

 what are known as bituminous and anthra- 

 cite coals. The former contains 20 per cent 

 or more of volatile matter. In burning they 

 give oft a strong bituminous odor with a heavy 

 black smoke and a yellowish flame. Some 

 bituminous coals are quite hard and slaty, 

 while others are soft and fibrous, crumbling 

 under rough handling. The forms that burn 

 with a short flame contain 80 to 90 per cent 

 of carbon and are called semi-bituminous, 

 while the rich bituminous coals which burn 

 with a very long flame, owing to the large 



contain but 65 to 75 per cent of carbon. 



Speaking of bituminous coals, William Kent 

 says in effect (Transactions of the American 

 Society of Mechanical Engineers, vol. 2, page 

 90): "If we draw a line from the Pocahontas 

 field on the boundary line between Virginia 

 and West Virginia, through Maryland, a little 

 west of Cumberland, and through Somerset, 

 Cambria and Clearfield counties in Pennsyl- 

 vania, it will pass through the coal field con- 

 taining the best steam coals mined in the 

 United States. These coals are very uniform 

 in their chemical composition, the combustible 



from 80 per cent fixed carbon, and 20 per cent 

 volatile matter. Their heating power is like- 

 wise remarkably uniform, averaging 15,750 

 B. T. U. per pound of combustible, with a 

 probable variation of not over two per cent 

 from this figure. The ash and moisture of all 

 the coals along this line are also very low, 

 the ash varying no doubt with the care used 

 in preparing the coal for market. These coals 

 are very properly classed as semi-bituminous. 

 "Traveling northwestwardly at right angles 

 to and from any point on this line, the coal 

 gradually increases in volat 



ing 



the 



ined 



•olatile matter is only about 

 20 per cent of the total weight of the com- 

 bustible matter, but it is nearly all of the 

 composition of marsh gas, CH4. having but 

 little oxygen and every pound of it Is worth 

 nearly 1% pounds of carbon. Farther to the 

 northwest, however, while the proportion of 

 the volatile matter Increases It becomes j>f 

 poorer quality, being high? 



coals are black, with a bright luster, and are 

 so hard that they stand transportation with 

 Mttle injury. Owing to the large amount of 

 carbon, they are, weight for weight, the most 

 valuable of coals. 



Coal Is extensivelv mined in 27 of the states 

 and territories. Anthracite coal Is found prin- 

 cipally In eastern Pennsylvania, although 

 mines have been opened in Colorado and New 

 Mexico. The states leading in the production 

 of bituminous coal are Pennsylvania. Illinois 

 and West Virginia, and in these states the 



the other states. 



The semi-bituminous coals of West Vlrglnl 

 Maryland and Pennsyl 



tated by 

 about" 19 per cent of volatile 

 latter and 70 per cent carbon. 

 The better bituminous coals of the states 



Chemical Analyses of Coal from Different 

 States. 



Bituminous Carbon. Vol. matter. Ash, 



vania coals it averages little if any more 

 than one per cent, while in Indiana coals it 

 averages 4 per cent, in Illinois 6 per cent and 



Variation in the Amount of Combustible 

 Matter. 



Profpssors Lord and Haas (Transactions of 

 the American Institute of Mining Engineers 

 1897), state that per pound of combust ble, all 

 coals from a given seam, over a considerable 

 area, have a substantially uniform heating 

 value per pound of the combustible portion. 

 * painstaking w 





chemical 

 s shows a con- 

 heating value 



of coal from the same region or even from the 

 same mine. The first difference is noted in the 

 amount of ash. Thus, in the better grades of 

 Lehigh and Lackawanna anthracite the per- 

 centage of ash la generally between 10 and 

 15. while in the pea, buckwheat and screen- 

 ings it may amount to 15 or 20. In bitumin- 

 ous coal we find the range even greater. In 

 Pocahontas. Cumberland and other seml-bl- 

 tuminous coals, actual tests show about 5 per 

 cent of non-combustlble material. Pittsburg 

 and Ohio coals usually contain from 6 to 10 

 per cent and as high as 12 per cent of dust 

 and slack. 



The coals of the western states show a small- 

 er percentage of carbon and a larger per- 

 centage of volatile matter than the bitumin- 

 ous coals of Pennsylvania, but the amount or 

 volatile matter does not necessarily determine 

 its calorific value, as, it the proportion of 

 oxygen is large, the heating value of the hy- 



No. 2 



lessened. 



preparation of anthracite coal for the 

 it is screened into various sizes, known 

 nboat (4 to 6 in.), broken (3 to 4 in.), 



to 2% in.), large stove (2 to 2-4 In.), 

 ove (1^4 to 1% in.), and chestnut (%/' 

 There 



local 

 fine coal graded ac- 

 a. No. 1 buckwheat, 

 buckwheat or rice, birds eye, No^ 3 



buc 



dus 



pass through perforations 3-32 of 

 diameter. Aside from the slight 

 the amount of slate and refuse 

 !se finer grades of coal, they con- 

 tain the same amount of combusJ.ible ma- 

 terials as the coarser grades. 





plied 



nmonly 

 grades of coal, while at 

 what is called "culm." 



the 



rovide a sufficient amount of air to 

 cure'perfect combustion, without using a 

 aught so strong as to draw the fine particles 



the 



or 



depth. • 

 With 



(1) Large grati 



unduly 

 combustion. On the other nana, wnen iiie 

 coal is loosened by the slice bar, much of it 

 shakes through the openings in the grate bars. 

 When fine coal, either anthracite or bitumin- 

 ous is burned under a boiler where tne 

 draught is gentle the best results are secured 

 1,-, >, = ..ing a thin fire, one to two inches in 

 while with a strong draught and hard 

 may be five or six inches deep, 

 too strong a draught, or too t^ln a 

 ^ gases are diluted and cooled, while 

 "draught is too weak or the fire too 

 for the draught, combustion will be 

 ete carbon monoxide will be formed 

 3 in heat will result. 



ing of these^'flne/ grl'des of anthracite coal 

 '"s °'..'. _. — i.g ^itj, a(r spaces of from 

 according to the size of 

 -es and frequent stoking, 

 bed diminishing with the 

 rS) arrangements for feed- 



mechanical stoker. 



Measurements of the Efficiency of Boilers. 



In order that there may be some common 

 basis for comparison, various measures of the 

 pfflciencv of boilers have been devised. A 

 iT"p nnwer was long since taken as. a stand- 

 fixed upon the 

 sam that they would require per 

 r as that developed from a cubic foot of 

 er or about 60 pounds, evaporated from 

 degrees, for each horse-power, or the 

 ing of 33,000 pounds continuously one foot 





efficiency of engines 



evaporation of 30 



agrees, or 34M: pounds 



212 degrees, at 70 pounds pr 

 regarded as the standard 

 a commercial horse-power. 

 Luother standard of measu' 

 the heating surface of the 

 . efficiency of boiler surface 



is based 

 m tested 



red for each horse-power. The average 

 lese many tests shows that about three 

 ds of water, from and at 212 degrees, can 

 vaporated from each foot of boiler sur- 



