Page 276 - Pipeline Rules of Thumb Handbook

Gas—General 263

These figures mean that mixtures of methane and air 5. Kvalnes, H. M. and V. L. Gaddy, J. Am. Chem. Soc. 53,
having less than 5% methane by volume are too lean to 394 (1931).
burn, those with more than 15% are too rich. The 6. Edmister, W. C., J. Vairogs and A. J. Klekers, AIChE
autoignition temperature is the minimum temperature Journal 14, No. 3, p. 479 (1968).
at which ignition can occur. Figures on flammable limits 7. Handbook of Chemistry and Physics, 47th Edition,
refer to “homogeneous” mixtures. Industrially, few mixtures 1966–67.
are completely homogeneous. In safety computations, 8. Huang, E. T. S., G. W. Swift and F. Kurata, AIChE
therefore, the engineer must establish that the “highest local Journal 12, p. 932 (1966).
concentration” is below the lower flammable limit by a suit- 9. Viswanath, D. S., AIChE Journal 13, 850 (1967).
able margin before saying there is no fire hazard. A method 10. Gamson, B. W., Chem. Eng. Prog. 45, 154 (1949).
dealing with LNG spills has been proposed by Parker and 11. Hirschfelder, J. O., R. B. Bird and E. L. Spotz, Trans.
Spata. 18 ASME 71, 921 (1949).
12. Hirschfelder, J. O., C. F. Curtiss and R. B. Bird, Molec-
ular Theory of Gases and Liquids, John Wiley and Sons,
References Inc., New York, 1954.
13. Matthews, C. S. and C. O. Hurd, Trans. AIChE 42, p. 55
1. Kobe, K. A. and R. E. Lynn, Chem. Revs. 52, 117 (1946); ibid., pp. 78 (1009).
(1953). 14. Perry, J. H. (ed.) Chemical Engineers Handbook, 3rd ed.,
2. American Petroleum Institute, “Selected Values of McGraw-Hill, New York, 1950.
Physical and Thermodynamic Properties of Hydrocarbons 15. Reid, R. C. and T. K. Sherwood, The Properties of Gases
and Related Compounds,” Project 44, Carnegie Press, and Liquids, McGraw-Hill, New York (1958).
Pittsburgh, Pa. 1953 (NBS-C-461). 16. Coward, H. F. and G. W. Jones, U.S. Bureau of Mines,
3. Nelson, L. C. and E. F. Obert, Trans. ASME 76, 1057 Bulletin 503 (1952).
(1954). 17. Zabetakis, M. G., U.S. Bureau of Mines, Bulletin 627
4. Benedict, M., G. B. Webb, L. C. Rubin and L. (1965).
Friend, Chem. Eng. Prog. 47, 419, 449, 571, 609 18. Parker, R. O. and J. K. Spata, Proc. 1st Intern. Conf. on
(1951). LNG, Chicago, April 7–12, 1968, Paper No. 24.

Conversion table for pure methane

Long tons ft 3 ft 3 m 3 m 3 U.S. bbl
liquid liquid gas liquid gas liquid Therms Thermies

long ton liquid = 1 84.56 52,886 2.394 1,419.7 15.06 535.2 13,491
3
ft liquid = 0.011826 1 625.43 0.028311 16.789 0.1781 6.329 159.54
3
ft gas ¥ 10 6 = 18.91 1,599 1 ¥ 10 6 45.27 26,847 284.785 10,121 255,115
3
m liquid = 0.4177 35.315 22,090 1 593 6.29 223.55 5,635.2
3
m gas ¥ 10 9 = 704,374 59.562 ¥ 10 6 37.252 ¥ 10 9 1.686 ¥ 10 6 1 ¥ 10 9 10.608 ¥ 10 6 0.377 ¥ 10 9 9.503 ¥ 10 9
U.S. bbl liquid = 0.0664 5.615 3,512 0.15896 94.268 1 35.54 895.8
Therm ¥ 10 6 = 1,868 157,958 98.791 ¥ 10 6 4,472 2.652 ¥ 10 6 28,132 1 ¥ 10 6 25.201 ¥ 10 6
Thermie ¥ 10 6 = 74.12 6,268 3.92 ¥ 10 6 177.44 105,228 1,116.2 39,669 1 ¥ 10 6
Notes
2
3
1. ft measured at 60°F, 14.696 lbf/in , dry
3
2. m measured at 0°C, 760 mmHg, dry
3
3. Gross heat content of methane is 1012 Btu/ft in gaseous forms: Specific gravity 0.554 (Air = 1)
2
Boiling point -258.7°F (14.696 lbf/in )
3
6
4. 1 ¥ 10 ft gas = 24.42 long tons (0.4417 b/d) fuel oil equivalent
5. The above factors are based on the properties of pure methane; LNG as shipped in practice will vary in composition according to the presence of heavier
hydrocarbons (C 2 , C 3 , C 4 ) in the gas stream.