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Literature Cited (1) Caldwell, B. P., and Mattiello, J., IND.ENQ.CHEM.,24, 158-62 (1932); Long, J. S.,and Wentz, G., Ibid., 18,1245-8 (1926); Long, J. S.,and Amer, W. J., Ibid., 18, 1252-3 (1926); Long, J. S., Egge, W. S., and Wetterau, P. C., Ibid., 19, 903-7 (1927); Long, J. S.,Reineck, A. E., and Ball, G. L., Ibid., 25, 1086-91 (1933); Rhodes, F. H., and Welz, C., Jr., Ibid.,
19, 68-73 (1927). (2) Carothers, W. H., J. Am. Chem. Soc., 51, 2548-59 (1929); Chem. Rev., 8, 353-426. (3) Carothers, W. H., and Arvin, J. A., J . Am. Chem. SOC., 51, 2560-70 (1929). (4) Elm, A. C., IND.ENQ.CHEM.,23, 881-6 (1931). (5) Jordan, L. A.,J. Oil Colour Chem. Assoc., 17, 47-66 (1934). (6) Jordan, L. A., and Cutter, J. O., J . SOC.Chem. I n d . , 54, 90T (1935). (7) Kharasch, M. S., and Mayo, F. R., J. Am. Chem. SOC.,55, 2468-96 (1933); Kharasch, M. S.,and McNab, M. C., J. SOC.Chem. Ind., 54, 989-90 (1935). (8) Kienle, R. H., IND.EIQ. CHEM.,22, 590-4 (1930). (9) Kienle, R. H., and Ferguson, C. S., Ibid., 21, 349-52 (1929) (10) Kienle, R.H., and Hovey, A. G., J . Am. Chem. SOC.,51,509-19 (1929);52, 3636-45 (1930);Kienle, R. H., IND.ENQ.CHEM., 23. 1260-1 (1931): 25. 971-5 (1933). (11) Kino’, K., Sei. Papers ‘Inst. P i y s . Chem. Research (Tokyo), 26, 61-7 (1935). (12) Long, J. S., and McCarter, W. S. M., IND.ENQ.CHEM.,23, 786-91 (1931); Long, J. S.,and Chataway, H. D., Ibid., 23, 53-7 (1931).
(13) Morrell, R. S., J . Oil Colour Chem. Assoc., 7, 159 (1924);Fonrobert, E., and Pallauf, F., Chem. Umschau, 33, 44 (1926); Miller, A. B.,and Claxton, E., IND.ENQ.CHEM.,20, 46-7 (1928); Miller, A. B., and Rohrbach, R., Ibid., 21, 338-42 (1929); Thurman, B. H., and Crandall, W. R., Ibid., 20, 1390-2 (1928); Kino, K., J. SOC. Chem. I n d . J a p a n , 33, Suppl., 153 (1930); Drinberg, A. Y.,and Blagonravova, A. A., J. Gen. C h m . (U. S. 9. R.), 5, 1226-32 (1935). (14) Morrell, R. S., J. SOC.Chem. I n d . , 34, 105-9 (1915). (15) Morrell, R. S.,and Marks, S., J. Oil. Colour Chem. Assoc., 12, 184-202 (1929). (16) Rossman, E., Fettehem. Umschau, 40, 96-123 (1933). (17) Staudinger, H.,Trans. Faraday SOC.,32 (I), 97 (1936). (18) Staudinger, H., and Huseman, E., Ber., 68, 1618 (1935); Staudinaer. H.. and Heuer. W.. Ibid.. 67. 1164-6 (1934): Staudinger; H.,’Heuer,W., and Huseman, E:, Trans. F k d a y SOC.,32 (I), 323-32 (1936). (19) Stephens, H.N., IND.ENQ.CHIM., 24, 918-20 (1932). (20) Tsuzuki, Y.,Bull. Chem. SOC.(Japan);lO, 17-26 (1935). (21) Ware, E. E., and Schumann, C. L., J. IND.ENQ.CHEM.,7, 571-3 (1915); Schumann, C. L., Ibid., 8,7-15 (1916). (22) Wornum, W. E.,J . Oil Coolour Chem. Assoc., 16, 231-42 (1933); 17, 119-45 (1934); Jordan, L. A.,Ibid., 17, 47-66 (1934); Cutter, J. 0..and Jordan, L. A.,Ibid., 18, 5-11 (1935). RECEIVED April 21,1936. Presented before the Division of Paint and Varnish Chemistry a t the 91st Meeting of the American Chemiaal Sooiety, Kansas City, Mo., April 13 to 17, 1936.
Flammability of Propane-Air Mixtures R a n g e at Low Pressures H.w.VAN DER H O m N N. V. De Bataafsche Petroleum FJIaatschappij, Amsterdam, Holland
LTHOUGH t h e explosive properties of mixtures of combustible gases and air have been repeatedly examined, most investigators have experimented with mixtures under atmospheric or increased pressure (1, I, 6). Only methane-air, hydrogen-oxygen, and carbon monoxide-oxygen mixtures have been studied a t low pressures (3, 4, ?‘), so that it seemed worth while t o publish some measurements on propane-air mixtures at reduced pressure. The limits of flammability of propane-air mixtures under reduced pressure were determined as follows (Figure 1): Measured quantities of propane and air were carefully mixed in a buret, E , over mercury. The air had previously been dried over calcium chloride and phosphorus pentoxide; the propane, which was freshly distilled, was already dry. Five to seven milliliters of the mixture were forced under pressure into an explosion buret, A , which contained two fused-in platinum electrodes, C (diameter about 0.3 mm., length in the gas 4.5 mm.), 1mm. apart. After the mixture had been introduced into the explosion buret ond the pressure had been adjusted to one atmos here, the buret was closed at the to , B, and the ressure reducefto the re uired extent by means o r a mercury-fiEed leveling bottle, D. 8ubsequently the gas was ignited by a s ark discharge between the electrodes, which was produced by a gord induction coil.
..
_. ..
After each determ i n a t i o n the remaining gas was expelled and the buret d r i e d b y moving the mercury level up and down several times; as a result the water formed evaporated in the fresh supply of dry air. T h e l i m i t s of FIGURE1. APPARATUSFOR THE DEflammability were TERMINATION OF EXPLOSION LIMITS approximated from AT PRESSURES BELOW ONE ATMOBPHERE b o t h sides. The same gas mixture was examined at different pressures until finally no further explosion occurred at low pressures. As was to be expected, the range of flammability was found to decrease a t lower pressures. With the apparatus used, the lowest pressure at which explosion still occurred was 210 mm. of mercury a t a concentration of 4 to 5 per cent propane by volume.
The results of these measurements are shown graphically by curve 111, Figure 2. The pressure in millimeters is plotted
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During the present investigation against the volume per on propane-air, no explosion could cent of h y d r o c a r b o n . be produced below 210 mm. of The points where ignimercury, even when the intensity tion occurred are marked of the spark was raised considerplus, the mixtures giving ably, so that the intensity of the no ignition, minus. The spark used certainly exceeded the graph includes for comabove-mentioned minimum parison, two exp 1o si o n value. c u r v e s (I and 11) for The curve for propane-air, therem e t h a n e - a i r mixtures fore, should be compared with according to data from curve I for methane, rather than t h e l i t e r a t u r e (3, 4). with curve 11. This leads to the Curves I and I1 deviate conclusion that the flammability of greatly from each other, propane-air mixtures ceases at a and at the same time the considerably higher pressure than lowest pressure at which that of methane-air. I n both cases an explosion still occurs the range of flammability decreases varies cons i d e r a b l y . rapidly with decreasing pressure in Curve I was o b t a i n e d the neighborhood of the lowest when using a tube 5 cm. pressure a t which i g n i t i o n in diameter, with horioccurs. z o n t a 1 propagation of the flame (3); curve 11, with a spherical exploLiterature Cited s i o n p i p e t of a b o u t I I Y . . -(1) Bone, W. A., Newitt, D. M., and 100-ml. capacity, with Townend, L. T. A., “Gaseous p l a t i n u m wires fused Combustion at High Pressures,” % V O ~ .OF Fuel New York and London, Longinto the upper part at a 0 I 2 3 4 5 6 7 8 9 l o l l 121314 16 mans, Green & Co., 1929. distance of inch (1.6 (2) Bone, W.A.,and Townend, D. T. A., mm.) from each other. FIQURE2. EXPLOSION LIMITS OF PROPANE-AIR AND “Flame and C o m b u s t i o n i n METHANE-AIR MIXTURESAS A FUNCTION OF PRESSURE Gases,” New York and London, I n the latter case the Longmans, Green & Co., 1927. spark was produced by (3) Ibid.,p. 503 [from Mallard and Le Chatelier. Ann. mines, 4, 347 means of an induction Coil fed by dry cells and only when (1883) 1. ‘park was it ‘Onsidered at the a gas mixture (4) Burrell, G. A,, and Robertson, I. W., U. S. Bur. Mines, Tech. to be “explosive.” Paper 121 (1916). (5) Duchene, R., “Etude de la combustion des m6langes gazeux,” By using a very powerful spark, however, an explosion Pub. soi. et tech. du ministere de l’air, Paris, Gauthier-Villars could be produced in methane-air mixtures containing 9 per & Cie, 1932. cent methane at a pressure as low as 200 mm. of mercury. (6) Lindeyer, E. W., “Explosiviteit van Gasmengaels,” dissertation, The lack of concurrence in these figures for methane-air must Leiden, 1935. (7) Mason, w., and Wheeler, V. W., J . Chem. Soc., 113, 45 (1918); therefore be ascribed to the fact that the intensity of the Chem. Zentr., 1919, I, 511. spark plays an important part. It is imperative that this intensity should not fall below a given minimum value, which RECEIVED November 20, 1936 generally increases with decreasing pressure (6). c
“PILOTPLANT”OPERATION IN THE SOCONY-VACUUM REFINERY AT PAULSBORO, N. J., WHERE THE REVOLUTIONARY NEWDuoSOLPROCESS Is Now IN OPERATION
Courtesy
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Cornpanu, I n c .
