Part 21
____________________________________________________________________________ | | | | | | | | | | | | No. | State | County | Field, Bed | Mine | Size | | | | or Vein | | | | | | | | | | | | | | | |_______|________________|________________|_______________|_____________| | | | | | | 169 | Va. | Lee | Darby | Darby | 1½ inch | 170 | Va. | Lee | McConnel | Wilson | Mine run | 171 | Va. | Wise | Upper Banner | Coburn | 3½ inch | 172 | Va. | Rockingham | | Clover Hill | | 173 | Va. | Russel | Clinchfield | | | 174 | Va. | | Monongahela | Bernmont | | 175 | W. Va.| Harrison | Pittsburgh | Ocean | Mine run | 176 | W. Va.| Harrison | | Girard | Nut, Pea | | | | | | and Slack | 177 | W. Va.| Kanawha | Winifrede | Winifrede | | 178 | W. Va.| Kanawha | Keystone | Keystone | Mine run | 179 | W. Va.| Logan | Island Creek | |Nut and Slack| 180 | W. Va.| Marion | Fairmont | Kingmont | | 181 | W. Va.| Mingo | Thacker | Maritime | | 182 | W. Va.| Mingo | Glen Alum | Glen Alum | Mine run | 183 | W. Va.| Preston | Bakerstown | | | 184 | W. Va.| Putnam | Pittsburgh | Black Betsy | Bug dust | 185 | W. Va.| Randolph | Upper Freeport | Coalton | Lump and Nut| ____|_______|________________|________________|_______________|_____________| | | | | | | LIGNITES AND LIGNITIC COALS | | ____|_______|_________________________________________________|_____________| | | | | | | 186 | Col. | Boulder | | Rex | | 187 | Col. | El Paso | | Curtis | | 188 | Col. | El Paso | | Pike View | | 189 | Col. | Gunnison | South Platte | Mt. Carbon | | 190 | Col. | Las Animas | | Acme | | 191 | Col. | | Lehigh | | | 192 |N. Dak.| McLean | | Eckland | Mine run | 193 |N. Dak.| McLean | | Wilton | Lump | 194 |N. Dak.| McLean | | Casino | | 195 |N. Dak.| Stark | Lehigh | Lehigh | Mine run | 196 |N. Dak.| William | Williston | | Mine run | 197 |N. Dak.| William | Williston | | Mine run | 198 | Tex. | Bastrop | Bastrop | Glenham | | 199 | Tex. | Houston | Crockett | | | 200 | Tex. | Houston | | Houston C. & | | | | | | C. Co. | | 201 | Tex. | Milam | Rockdale | Worley | | 202 | Tex. | Robertson | Calvert | Coaling No. 1 | | 203 | Tex. | Wood | Hoyt | Consumer's | | | | | | Lig. Co. | | 204 | Tex. | Wood | Hoyt | | | 205 | Wash. | King | | Black Diamond | | 206 | Wyo. | Carbon | Hanna | | Mine run | 207 | Wyo. | Crook | Black Hills | Stilwell Coal | | | | | | Co. | | 208 | Wyo. | Sheridan | Sheridan | Monarch | | 209 | Wyo. | Sweetwater | Rock Spring | | Screenings | 210 | Wyo. | Uinta | Adaville | Lazeart | | ____|_______|________________|________________|_______________|_____________|
_____________________________________________________________________ | | | | | Proximate Analysis (Dry Coal) |B. t. u.| | No. |________________________________________| Per | | | | | | | Pound | Authority | | Moisture | Volatile | Fixed | Ash | Dry | | | | Matter | Carbon | | Coal | | ____|__________|__________|________|_________|________|______________| | | | | | | | 169 | 4.35 | 38.46 | 56.91 | 4.63 | 13939 | U. S. Geo. S.| 170 | 3.35 | 36.35 | 57.88 | 5.77 | 13931 | U. S. Geo. S.| 171 | 3.05 | 32.65 | 62.73 | 4.62 | 14470 | U. S. Geo. S.| 172 | | 31.77 | 57.98 | 10.25 | 13103 | | 173 | 2.00 | 35.72 | 56.12 | 8.16 | 14200 | | 174 | | 32.00 | 59.90 | 8.10 | 13424 | Carpenter | 175 | 2.47 | 39.35 | 52.78 | 7.87 | 14202 | U. S. Geo. S.| 176 | | 36.66 | 57.49 | 5.85 | 14548 | B. & W. Co. | | | | | | | | 177 | 1.05 | 32.74 | 64.38 | 2.88 | 14111 | Hill | 178 | 2.21 | 33.29 | 58.61 | 8.10 | 14202 | U. S. Geo. S.| 179 | 1.12 | 38.61 | 55.91 | 5.48 | 14273 | Hill | 180 | 1.90 | 35.31 | 57.34 | 7.35 | 14198 | U. S. Geo. S.| 181 | 0.68 | 31.89 | 63.48 | 4.63 | 14126 | Hill | 182 | 3.02 | 33.81 | 59.45 | 6.74 | 14414 | U. S. Geo. S.| 183 | 4.14 | 29.09 | 63.50 | 7.41 | 14546 | U. S. Geo. S.| 184 | 7.41 | 32.84 | 53.96 | 13.20 | 12568 | B. & W. Co. | 185 | 2.11 | 29.57 | 59.93 | 10.50 | 13854 | U. S. Geo. S.| ____|__________|__________|________|_________|________|______________| | | | | | | | | | | | | | | ____|__________|__________|________|_________|________|______________| | | | | | | | 186 | 16.05 | 42.12 | 47.97 | 9.91 | 10678 | B. & W. Co. | 187 | 23.25 | 42.11 | 49.38 | 8.51 | 11090 | B. & W. Co. | 188 | 23.77 | 48.70 | 41.47 | 9.83 | 10629 | B. & W. Co. | 189 | 20.38 | 46.38 | 47.50 | 6.12 | | | 190 | 16.74 | 47.90 | 44.60 | 7.50 | |Col. Sc. of M.| 191 | 18.30 | 45.29 | 44.67 | 10.04 | | | 192 | 29.65 | 45.56 | 47.05 | 7.39 | 10553 | Lord | 193 | 35.96 | 49.84 | 38.05 | 12.11 | 11036 | U. S. Geo. S.| 194 | 29.65 | 46.56 | 38.70 | 14.74 | | Lord | 195 | 35.84 | 43.84 | 39.59 | 16.57 | 10121 | U. S. Geo. S.| 196 | 41.76 | 39.37 | 48.09 | 12.54 | 10121 | B. & W. Co. | 197 | 42.74 | 40.83 | 47.79 | 11.38 | 10271 | B. & W. Co. | 198 | 32.77 | 42.76 | 36.88 | 20.36 | 8958 | B. & W. Co. | 199 | 23.27 | 40.95 | 38.37 | 20.68 | 10886 | U. S. Geo. S.| 200 | 31.48 | 46.93 | 34.40 | 18.87 | 10176 | B. & W. Co. | | | | | | | | 201 | 32.48 | 43.04 | 41.14 | 15.82 | 10021 | B. & W. Co. | 202 | 32.01 | 43.70 | 43.08 | 13.22 | 10753 | B. & W. Co. | 203 | 33.98 | 46.97 | 41.40 | 11.63 | 10600 | U. S. Geo. S.| | | | | | | | 204 | 30.25 | 43.27 | 41.46 | 15.27 | 10597 | | 205 | 3.71 | 48.72 | 46.56 | 4.72 | | Gale | 206 | 6.44 | 51.32 | 43.00 | 5.68 | 11607 | B. & W. Co. | 207 | 19.08 | 45.21 | 46.42 | 8.37 | 12641 | U. S. Geo. S.| | | | | | | | 208 | 21.18 | 51.87 | 40.43 | 7.70 | 12316 | U. S. Geo. S.| 209 | 7.70 | 38.57 | 56.99 | 4.44 | 12534 | B. & W. Co. | 210 | 19.15 | 45.50 | 48.11 | 6.39 | 9868 | U. S. Geo. S.| ____|__________|__________|________|_________|________|______________|
[Illustration: Portion of 12,080 Horse-power Installation of Babcock & Wilcox Boilers and Superheaters at the Potomac Electric Co., Washington, D. C.]
TABLE 39
SHOWING RELATION BETWEEN PROXIMATE AND ULTIMATE ANALYSES OF COAL
========================================================================= | | | | Common in | | | | |Proximate &| | | Proximate | | Ultimate | | | Analysis | Ultimate Analysis | Analysis | |--------------------|-----------|--------------------------|-----------| | | | | V | | | H | | N | | | M | | | | | o | | | y | | i | S | | o | | | | | l M | C | C | d | O | t | u | | i | | S | | | a a | F a | a | r | x | r | l | | s | | t | | | t t | i r | r | o | y | o | p | | t | | a | Field | | i t | x b | b | g | g | g | h | A | u | | t | or | | l e | e o | o | e | e | e | e | s | r | | e | Bed | Mine | e r | d n | n | n | n | n | r | h | e | |---|-------|--------|-----|-----|-----|----|-----|----|----|-----|-----| | | |Icy Coal| | | | | | | | | | | | | & Iron | | | | | | | | | | | | Horse | Co. | | | | | | | | | | |Ala| Creek | No. 8 |31.81|53.90|72.02|4.78| 6.45|1.66| .80|14.29| 2.56| |---|----------------|-----|-----|-----|----|-----|----|----|-----|-----| | | |Central | | | | | | | | | | | | |C. & C. | | | | | | | | | | | | Hunt- | Co. | | | | | | | | | | |Ark|ington | No. 3 |18.99|67.71|76.37|3.90| 3.71|1.49|1.23|13.30| 1.99| |---|-------|--------|-----|-----|-----|----|-----|----|----|-----|-----| | | Pana | Clover | | | | | | | | | | | | or | Leaf, | | | | | | | | | | |Ill| No. 5 | No. 1 |37.22|45.64|63.04|4.49|10.04|1.28|4.01|17.14|13.19| |---|-------|--------|-----|-----|-----|----|-----|----|----|-----|-----| | |No. 5, | | | | | | | | | | | | |Warrick| | | | | | | | | | | |Ind| Co. |Electric|41.85|44.45|68.08|4.78| 7.56|1.35|4.53|13.70| 9.11| |---|-------|--------|-----|-----|-----|----|-----|----|----|-----|-----| | |No. 11,| St. | | | | | | | | | | | |Hopkins|Bernard,| | | | | | | | | | |Ky | Co. | No. 11 |41.10|49.60|72.22|5.06| 8.44|1.33|3.65| 9.30| 7.76| |---|-------|--------|-----|-----|-----|----|-----|----|----|-----|-----| | |"B" or | | | | | | | | | | | | |Lower | | | | | | | | | | | | |Kittan-| Eureka,| | | | | | | | | | |Pa | ning | No. 31 |16.71|77.22|84.45|4.25| 3.04|1.28| .91| 6.07| .56| |---|-------|--------|-----|-----|-----|----|-----|----|----|-----|-----| | |Indiana| | | | | | | | | | | |Pa | Co. | |29.55|62.64|79.86|5.02| 4.27|1.86|1.18| 7.81| 2.90| |---|-------|--------|-----|-----|-----|----|-----|----|----|-----|-----| |W. | Fire | Rush | | | | | | | | | | |Va | Creek | Run |22.87|71.56|83.71|4.64| 3.67|1.70| .71| 5.57| 2.14| =========================================================================
Table 39 gives for comparison the ultimate and proximate analyses of certain of the coals with which tests were made in the coal testing plant of the United States Geological Survey at the Louisiana Purchase Exposition at St. Louis.
The heating value of a fuel cannot be directly computed from a proximate analysis, due to the fact that the volatile content varies widely in different fuels in composition and in heating value.
Some methods have been advanced for estimating the calorific value of coals from the proximate analysis. William Kent[38] deducted from Mahler's tests of European coals the approximate heating value dependent upon the content of fixed carbon in the combustible. The relation as deduced by Kent between the heat and value per pound of combustible and the per cent of fixed carbon referred to combustible is represented graphically by Fig. 23.
Goutal gives another method of determining the heat value from a proximate analysis, in which the carbon is given a fixed value and the heating value of the volatile matter is considered as a function of its percentage referred to combustible. Goutal's method checks closely with Kent's determinations.
All the formulae, however, for computing the calorific value of coals from a proximate analysis are ordinarily limited to certain classes of fuels. Mr. Kent, for instance, states that his deductions are correct within a close limit for fuels containing more than 60 per cent of fixed carbon in the combustible, while for those containing a lower percentage, the error may be as great as 4 per cent, either high or low.
While the use of such computations will serve where approximate results only are required, that they are approximate should be thoroughly understood.
Calorimetry--An ultimate or a proximate analysis of a fuel is useful in determining its general characteristics, and as described on page 183, may be used in the calculation of the approximate heating value. Where the efficiency of a boiler is to be computed, however, this heating value should in all instances be determined accurately by means of a fuel calorimeter.
[Graph: B.T.U. per Pound of Combustible against Per Cent of Fixed Carbon in Combustible
Fig. 23. Graphic Representation of Relation between Heat Value Per Pound of Combustible and Fixed Carbon in Combustible as Deduced by Wm. Kent.]
In such an apparatus the fuel is completely burned and the heat generated by such combustion is absorbed by water, the amount of heat being calculated from the elevation in the temperature of the water. A calorimeter which has been accepted as the best for such work is one in which the fuel is burned in a steel bomb filled with compressed oxygen. The function of the oxygen, which is ordinarily under a pressure of about 25 atmospheres, is to cause the rapid and complete combustion of the fuel sample. The fuel is ignited by means of an electric current, allowance being made for the heat produced by such current, and by the burning of the fuse wire.
A calorimeter of this type which will be found to give satisfactory results is that of M. Pierre Mahler, illustrated in Fig. 24 and consisting of the following parts:
A water jacket A, which maintains constant conditions outside of the calorimeter proper, and thus makes possible a more accurate computation of radiation losses.
The porcelain lined steel bomb B, in which the combustion of the fuel takes place in compressed oxygen.
[Illustration: Fig. 24. Mahler Bomb Calorimeter]
The platinum pan C, for holding the fuel.
The calorimeter proper D, surrounding the bomb and containing a definite weighed amount of water.
An electrode E, connecting with the fuse wire F, for igniting the fuel placed in the pan C.
A support G, for a water agitator.
A thermometer I, for temperature determination of the water in the calorimeter. The thermometer is best supported by a stand independent of the calorimeter, so that it may not be moved by tremors in the parts of the calorimeter, which would render the making of readings difficult. To obtain accuracy of readings, they should be made through a telescope or eyeglass.
A spring and screw device for revolving the agitator.
A lever L, by the movement of which the agitator is revolved.
A pressure gauge M, for noting the amount of oxygen admitted to the bomb. Between 20 and 25 atmospheres are ordinarily employed.
An oxygen tank O.
A battery or batteries P, the current from which heats the fuse wire used to ignite the fuel.
This or a similar calorimeter is used in the determination of the heat of combustion of solid or liquid fuels. Whatever the fuel to be tested, too much importance cannot be given to the securing of an average sample. Where coal is to be tested, tests should be made from a portion of the dried and pulverized laboratory sample, the methods of obtaining which have been described. In considering the methods of calorimeter determination, the remarks applied to coal are equally applicable to any solid fuel, and such changes in methods as are necessary for liquid fuels will be self-evident from the same description.
Approximately one gram of the pulverized dried coal sample should be placed directly in the pan of the calorimeter. There is some danger in the using of a pulverized sample from the fact that some of it may be blown out of the pan when oxygen is admitted. This may be at least
## partially overcome by forming about two grams into a briquette by the
use of a cylinder equipped with a plunger and a screw press. Such a briquette should be broken and approximately one gram used. If a pulverized sample is used, care should be taken to admit oxygen slowly to prevent blowing the coal out of the pan. The weight of the sample is limited to approximately one gram since the calorimeter is proportioned for the combustion of about this weight when under an oxygen pressure of about 25 atmospheres.
A piece of fine iron wire is connected to the lower end of the plunger to form a fuse for igniting the sample. The weight of iron wire used is determined, and if after combustion a portion has not been burned, the weight of such portion is determined. In placing the sample in the pan, and in adjusting the fuse, the top of the calorimeter is removed. It is then replaced and carefully screwed into place on the bomb by means of a long handled wrench furnished for the purpose.
The bomb is then placed in the calorimeter, which has been filled with a definite amount of water. This weight is the "water equivalent" of the apparatus, _i. e._, the weight of water, the temperature of which would be increased one degree for an equivalent increase in the temperature of the combined apparatus. It may be determined by calculation from the weights and specific heats of the various parts of the apparatus. Such a determination is liable to error, however, as the weight of the bomb lining can only be approximated, and a considerable portion of the apparatus is not submerged. Another method of making such a determination is by the adding of definite weights of warm water to definite amounts of cooler water in the calorimeter and taking an average of a number of experiments. The best method for the making of such a determination is probably the burning of a definite amount of resublimed naphthaline whose heat of combustion is known.
The temperature of the water in the water jacket of the calorimeter should be approximately that of the surrounding atmosphere. The temperature of the weighed amount of water in the calorimeter is made by some experimenters slightly greater than that of the surrounding air in order that the initial correction for radiation will be in the same direction as the final correction. Other experimenters start from a temperature the same or slightly lower than the temperature of the room, on the basis that the temperature after combustion will be slightly higher than the room temperature and the radiation correction be either a minimum or entirely eliminated.
While no experiments have been made to show conclusively which of these methods is the better, the latter is generally used.
After the bomb has been placed in the calorimeter, it is filled with oxygen from a tank until the pressure reaches from 20 to 25 atmospheres. The lower pressure will be sufficient in all but exceptional cases. Connection is then made to a current from the dry batteries in series so arranged as to allow completion of the circuit with a switch. The current from a lighting system should not be used for ignition, as there is danger from sparking in burning the fuse, which may effect the results. The apparatus is then ready for the test.
Unquestionably the best method of taking data is by the use of co-ordinate paper and a plotting of the data with temperatures and time intervals as ordinates and abscissae. Such a graphic representation is shown in Fig. 25.
[Graph: Temperature--° C. against Time--Hours and Minutes
Fig. 25. Graphic Method of Recording Bomb Calorimeter Results]
After the bomb is placed in the calorimeter, and before the coal is ignited, readings of the temperature of the water should be taken at one minute intervals for a period long enough to insure a constant rate of change, and in this way determine the initial radiation. The coal is then ignited by completing the circuit, the temperature at the instant the circuit is closed being considered the temperature at the beginning of the combustion. After ignition the readings should be taken at one-half minute intervals, though because of the rapidity of the mercury's rise approximate readings only may be possible for at least a minute after the firing, such readings, however, being sufficiently accurate for this period. The one-half minute readings should be taken after ignition for five minutes, and for, say, five minutes longer at minute intervals to determine accurately the final rate of radiation.
Fig. 25 shows the results of such readings, plotted in accordance with the method suggested. It now remains to compute the results from this plotted data.
The radiation correction is first applied. Probably the most accurate manner of making such correction is by the use of Pfaundler's method, which is a modification of that of Regnault. This assumes that in starting with an initial rate of radiation, as represented by the inclination of the line AB, Fig. 25, and ending with a final radiation represented by the inclination of the line CD, Fig. 25, that the rate of radiation for the intermediate temperatures between the points B and C are proportional to the initial and final rates. That is, the rate of radiation at a point midway between B and C will be the mean between the initial and final rates; the rate of radiation at a point three-quarters of the distance between B and C would be the rate at B plus three-quarters of the difference in rates at B and C, etc. This method differs from Regnault's in that the radiation was assumed by Regnault to be in each case proportional to the difference in temperatures between the water of the calorimeter and the surrounding air plus a constant found for each experiment. Pfaundler's method is more simple than that of Regnault, and the results by the two methods are in practical agreement.
Expressed as a formula, Pfaundler's method is, though not in form given by him:
_ _ | R' - R | C = N|R + ------ (T" - T)| (19) |_ T' - T _|
Where C = correction in degree centigrade, N = number of intervals over which correction is made, R = initial radiation in degrees per interval, R' = final radiation in degrees per interval, T = average temperature for period through which initial radiation is computed, T" = average temperature over period of combustion[39], T' = average temperature over period through which final radiation is computed.[39]
The application of this formula to Fig. 25 is as follows: