INDUSTRIAL AND ENGINEERING CHEMISTRY
February, 1925
165
Determination of Temperatures of Plasticity, Maximum Pressures, and Solidification of Cokinb Coals’ By E, T. Layng and W. S. Hathorne UNIVERSITY O F ILLINOIS, U R B A N A ,
ILL.
of which he measures the HE trend of progress A description of the apparatus and the method by which resistance of the passage of in fuels and fuel the temperaturesof initial plasticity, maximum pressures, gas through coal a t different technology is becomand initial solidification into coke has been given for temperatures in order to ing more diversified each forty-two coals. The results are possible of verification determine the path of travel year. Yet before it is possiby other operators, and give promise of being of value of gases in coke ovens, and ble to attack the many prob(a) in aiding in the classification of those coals which he has since published some lems of coal carbonization soften on heating, (b) in tracing any particular seam of of the results of his findings intelligently from the newer coal, (c) in determining the particular state of a coal on the critical temperatures viewpoint of low-temperawhich has been weathered for sometime, and (d) in defor British coals. ture process, more informatermining the resultant coal formed by mixing two coals In 1921 a t the Pittsburgh tion must be obtained conas in modern coking practice. meeting of the American cerning the constitution of Chemical Society, the aucoal. Many references indicate that coal is in a critical stage, thors gave notice and some data of their work on American coals using a somewhat similar method. The present paper is a re80 far as processes of carbonization are concerned, from the time it begins to become pasty or plastic to the time it is port of the method used and some of the data obtained. A flt/v.o/+lYe f E 8
T
INkf
Ir MANOMEfE
-4sa rocks
4
Figure 1-Melting
againa solid mass. The greatvariation in the temperatures indicated points either to inaccurate methods for the determination of these temperatures or to a wide variation in the materials used. Foxwell2 describes an apparatus by means Received August 12, 1924. Presented before the Section of Gas and Fuel Chemistry a t the 68th Meeting of the American Chemical Society, Ithaca, N. Y., September 8 t o 13.1924. J . Sac. Chem. I n d . , 40, l93T (1921).
and Solidification Temperature Apparatus
later paper will discuss their method of checking the accuracy of the data obtained as well as the significance of the data Apparatus
The apparatus consists essentially of an electric furnace in which the heating of the coal may be accurately controlled, a device that supplies a constant volume of nitrogen to the tube containing the coal, a manometer to measure the pres-
I N D UXTRIAL A N D ENGINEERIhrG CHEMISTRY
166
sure developed, and a pyrometer for measuring the temperature. The constant supply of nitrogen is obtained with a constant head apparatus connected to a 12-liter bottle. This
Vol. 17, No. 2
connected to the bottom of the tube of the furnace. I n this line is put a T tube that connects to a manometer. The manometer is of the U tube type with a capacity of 1450 mm. of water. The furnace is mounted so that the tube containing the coal stands vertically. The internal diameter of the furnace is 10 cm. and the length 50 cm., being closed a t the bottom and top and fitted with a stirring fan to maintain a constant temperature throughout the internal space. By means of a rheostat any desired temperature or speed of heating can be obtained. The coal is placed in a Pyrex tube of 14 mm. internal diameter. A copper spiral 10 om. long placed in this tube serves the dual purpose of holding the coal in place and removing any traces of oxygen that may be present in the nitrogen, Preparation of Sample
Freshly mined coal of large size makes the most satisfactory final samples. Weathering has a very great effect upon the melting point. Coals which pass 20-mesh screen and remain on 60-mesh were finally used, largely because they contributed to more even packing. Manipulation
head was copied after the types used on a Junker calorimeter and has a head of 1475 mm. of water. The volume of water delivered to:the bottle is regulated by means of two stopcocks, one of which is set permanently to deliver 40 cc. per minute and the other is used to shut the water supply off completely when the head is not in use. The gas is taken off of the top of the nitrogen bottle and
The copper gauze is placed in such a position in the tube that the bottom of the 10 cm. of coal comes about 5 cm. above the center of the furnace. The coal is poured into the tube and rapped until it settles to about 10 cm. in length and an initial pressure to the passage of nitrogen of about 40 mm. The tube is then connected with, the nitrogen and the furnace brought to 280" C. at the rate of about 10" C. per minute and the flow of nitrogen sent through the coal tube by turning on the water of the constant head apparatus and opening the shutoff cock. Readings of time, temperature, and manometer are then recorded every 3 to 5 minutes until the coal has passed through its critical stage and again shows a constant pressure to the flow of nitrogen. A variation of this method, in which no gas is passed through the coal during the critical stage, will be shown in a later paper. Figure 2 gives a typical set of data plotted graphically. Tables I, 11, and I11 show the record of some of the coals analyzed. Discussion of Results The temperatures of initial plasticity of the coal and initial solidification into coke have been given for forty-two coals. Check results to 1 or 2 degrees for the initial plas-
Table I-Illinois No.
COUNTY
MINE
Bituminous Softening Maximum temgerature pressure C. Mm.
Temperature of maximum pressure e
c.
Coke formation O c .
Length coke Cm.
Seam I
1 2
Henry Fulton
Rex No. 5
404 405
455 428
436 446
462 472
375 500 810 580 280 333 475 555 5 64 605 660 833 735
435 429 445 446 425 446 438 461 429.5 438 430 451 425 425
445 459 460 470 452 470 475 4s5 460 463 475 480
11 12
43s 467
508 481 62 445 430
10 12
450 450
..*.
11 10
Seam 5
6 7 S 9 10 11 12 13 14 15 16
Tazewell Sangamon Sangamon Sangamon Fulton Knox Knox McLean Peoria Macon Saline Saline Gallatin Gallatin
Groveland No. 2 Peerless No. 54 No. 55 Silver Creek Milan Adcock McLean Edwards Macon Big Creek O'Gara Coal Co. Gallatin Coal Co. Hickory Hill
392 381 395 392 380 408 402 402 405 412 380 377 354 357
17 18 19 20 21 22 23
Knox Franklin Franklin Vermilion Moultrie Williamson Franklin
Peterson W. Frankfort Zeigler No. 1 Taylor-English Lovington No. 8 Makitan
412 387 372 375 343 409 374
24 25
Vermilion V ermi 1ion
No. 6 Electric No. 4 Electric
361 361
3 4 5
..
13.5 11
IO 9.5 11.5 11.5 10 12 10
.. .. ..
Seam 6
1250 915 32 504 812 71 60
390 393 445 406
730 504
407 390
....
Seam 7
8 13
11
.. ..
I N D U S T R I A L A N D ENGINEERING CHEiMIXTRY
February, 1925
Table 11-Eastern
No. 2R ~.
27 28 29 30 31 32 33 34 35 36
DESCRIPTION Raleigh Co W. Va. Glogora Coal c o . Harlan Co "Ky Jellico Seam Fayette C 6 Pa.. Pittsburgh Seam H. C. Frick Co. Letcher Co" Ky. Elkhorn Seam. Inland Steel Co. Letcher Co:: KY. Elkhorn Seam. Eaton Rhodes Co. Letcher Co.. KY. Elkhorn Seam. Eaton Rhodes Co. Indianola Pa. Inland Steel Co. Raleigh do., W. Va. Jefferson Co., Ala. Pratt Seam Berwind Colo Colorado Fuel & Iron Co. Fire Cre6k Sesm, W. Va. Scotia Coal Co. ~~
.
ticity temperature may be easily obtained by different operators, but as yet the value listed for the solidification temperature is possible of a variation of about 10" C. As pointed out under the preparation of the sample, it is necessary to make the determination as soon as possible after the finely ground sample has been prepared or else evacuate the air in the sample bottle and replace with nitrogen. I n fact, a large number of the samples sent to the authors for analysis showed no melting or softening point because the coals had oxidized in transmission. The authors expect soon to present their results on the effects of weathering upon the temperature of plasticity and solidification. It will be noticed that the coals for the State of Illinois are listed under the seam from which they come. Although as
Bituminous
Softening temperature OC. 366 375 379 400 390 393 365 370 400 400 370
Maximum pressure Mm. 842 914 980 378 750 450 931 557 950 662 1310
42
DESCRIPTION Pocahontas No. 3 W. Va. Inland Steel Co. Fayette Co., W. $a. Sewell Seam. Inland Steel Co. Pocahontas No. 3 W Va. Pocahontas Fuel Co. Sewell Seam, N e d Riber District, W. Va. Cranberry Fuel Co. McDowell Co., W. Va., Pocahontas No. 4. U.S. Coal and Coke Co. Green Brier Co., W. Va. Pocahontas No. 3
Temperature of maximum pressure e c . 460 407 415 427 422 455 418 447 430 442 462
Coke formation O
c.
492 515 525 555 445 480 525 467 450 478 502
Length coke Cm. 14
11 12 10 11 16 14
..
20 12 18
yet nothing definite may be concluded in regard to the temperature a t which coals of the different seams become plastic, in general the temperature is lower, the younger the coal is geologically. I n fact, the authors believe the method may be of advantage in identifying the seam to which a coal belongs. This fact is borne out in the sample of Pocahontas and New River Semibituminous coals of West Virginia. The proximate analysis may indicate that the coals are quite similar, but their temperatures of initial plasticity indicate clearly that the New River coals contain lower melting compounds than those of the Pocahontas seams. As yet the authors have not analyzed a sufficiently large number of Eastern Bituminous coals to be able to show any particular characteristics.
Table 111-Semibituminous
No. 37 38 39 40 41
167
Softening temperature
428 385 430 390
Maximum pressure Mm. 1300 1370 1500 1425
428 407
1185 1421
O
c.
Temperature of maximum pressure
c.
505 520 472 537 543 601
Coke formation O c . 597 569 546 580
590 557
Length coke Cm. 10 18 12 16.5
11 23
Arsenated Petroleum Oil as a Wood Preservative' By W. Lee Tanner THE GRASSELLI CHEMICAL Co., CLEVELAND, On10
XPERIMENTATION in wood treating where a meE dium petroleum fraction containing a small proportion of an organic compound of arsenic is used reveals properties of the treated wood toward decay and depredation of marine animals and insects which may be of great economic value. Timbers treated by the Bethell, Burnett, and Card processes were given the same tests along with the arsenated petroleum oil method. The resistance to teredo and limnoria destruction was especially determined. These marine borers were never found in any of the timbers given the treatment of arsenated oil during the 4-year period through which these tests extend, whereas in the test timbers given the Burnett treatment they had destroyed much of the wood, and in the Bethell and Card processes of treatment the timber samples were filled with many teredos. The test timbers were southern pine of pile size cut to meter lengths, the bark being removed. They were placed in an autoclave and evacuated for 2 hours at 80 O C. The preserving fluid was run in and the pressure built up to 125 pounds a t a temperature less than 200" C. where it was maintained until the proper penetration was reached. I n the arsenated petroleum oil process, however, a simple open tank was used and the timbers were immersed under atmospheric pressure only. The treated timbers were given the most drastic testing easily possible. Some were placed in sea water on the surface of the mud along with checks treated and untreated where there existed an abundant supply of teredo. Others were 1
Received June 26, 1924.
placed in fungi pits. Exhaustive records of the careful and frequent observations were kept. The arsenated petroleum oil treatment showed resistance to both decay and destruction superior to all the other methods. Railway and mine timbers painted with the arsenated oil are under observation, and give promise of excellent preservation against decay. This method of commercial wood preserving offers great promise as a substitute for expensive treatment involving a great amount of equipment such as pressure tanks, pumps, etc. Simple open vats serve to make the application, or the preserving material may be painted or sprayed on the surfaces to be protected. The cost is less than one-half that of any of the other successful processes. The arsenic compounds are produced cheaply from the base, white arsenic and salt, and may be readily added to the oilin which they are soluble to a sufficient extent-at the factory, or they may be sold separately and incorporated with the oil medium a t the wood-treating works. The loss of the active principle by dissipation in sea water in the timbers treated has been found to be less than 1 per cent per year. The petroleum used most advantageously was a paraffin melting at 40" C. The material was applied a t about 100" C . The arsenic compounds proving satisfactory in these tests are phenarsazine chloride, phenarsazine oxide, diphenylchloroarsine, and nitrosodimethylanilinechloroarsine. Other and similar tests with arsenic-phenol preparations have been under way by the Chemical Warfare Service in connection with tests a t Beaufort, N. C .
