Document DvLrGEbgbJjBrb9J6La86BqYn

i ii 522 G. W. JONES This law has been tested by Coward, Carpenter, and Payman1 and proved! to hold for hydrogen, carbon monoxide, and methane containing no inert gases! in normal air. Subsequent tests made with paraffin hydrocarbons in air3 showed! that the law could also be applied to these mixtures. Exceptions have been found! in tests made with some flammable gases. White22 found that the law does no| hold strictly for hydrogen-ethylene-air mixtures, acetylene-hydrogen-air mixtures-,| hydrogen sulfide-methane-air mixtures, and mixtures containing carbon dir| sulfide. In tests on some chlorinated hydrocarbons, Coward and Jones60 foi that the law did not hold for methane-dichloroethylene-air mixtures. It was found32 to be only approximately correct for mixtures of methyl'and ethvl ^ chlorides. It is therefore apparent that the mixture law, useful when its appli cability has been proved, cannot be applied indiscriminately, but must first 1 j proved to hold for the combination of gases under investigation. Many industrial processes require the use of mixtures of various solventsl and although the limits of flammability of the various individual constituents in the mixture may be known, it is not at all certain what the limits of flammability! will be for the various mixtures. Investigations of the lower limits of flammability! of various solvent mixtures have shown30 that where the ratios of lower limits o|L the individual constituents to the amount of oxygen required for theoretical complete combustion are about the same, the limits of mixtures of the con|| stituents may be determined accurately by calculation. For example, limits mafj be calculated20 for mixtures of benzene, furfural, and acetone, which have ranging -from--0.-50 -to-&.53; and mixtures of ethyl acetate, ethyl alcohol] toluene, whose ratios vary from 0.50 to 0.56, also have been found36 to givff calculated results agreeing closely with experimental results. To date, the accuracy of the above prediction has been proved only for i limited number of mixtures. As information on the subject is accumulated, the classification of compounds according to the ratios should be of considerable value in predicting and calculating the limits of flammability of mixtures combustible gases and vapors. S. Complex Gas Mixtures It is possible to calculate closely the limits of flammability not only of mixtufesTFcombustiBle^"gases' and vapors, in air: but also mixtures containi|ji varying amounts`of inert gases , and air. The limits of flammability of natufalffl manufactured, producer, blast-furnace, automobile, and sewage gases when mixgM with various proportions of the inert gases present may be calculated frgmjgf _knowledge-of--the-composition'-of--the-gas-and-the-flammability-of-tKe^variptii constituents present. The actual procedure is rather long and complicated aij||^ tables or graphs are required for ascertaining the limits of the combustible-ine^ " M. J. Burgess and R. V. Wheeler, J. Chem. Soc., 99, 2013 (1911). * W. M. Thornton, Phil. Mag., 33, 190 (1917). "H. F. Coward and G. W. Jones, Ind. Eng. Chem., 22, 963 (1930). HAZARDS OF COMBUSTIBLE GASES AND VAPORS 523 !||,s components. The reader who wishes to make such calculations is referred "^published reports on the subjeot.2'33'55'01 D. LIMITS OF FLAMMABILITY OF GASES AND VAPORS IN OXYGEN TTn some instances, for example, the compressed-gas industry and in hospitals, inflammability of combustible gases in oxygen is of real importance. Published formation on this phase of the subject is limited, and in many' cases the values gnear to be unreliable. A compilation of the best available information on the g|||it8 in oxygen is given in Table 2. Ik Su table 2 Limits of Flammability of Gases and Vapors in Oxygen Limits of flammability (per cent by volume) Name ffetaldehyde ttxQtylQne Pruiionia . Benzene t|uinc potijutane .jebe^l ie-2 HP|ph monoxide SmOropropene ^rfityl bromide jsro|}'l chloride glo'fSropane ifluj&ium ..ilbroethylene USsM'l ether ijrl ether jgi|my!i''ether IfejEyfbromide |fe|Ssifchloride ro lather Jjjahe ggtnyl bromide HJjji';chloride ItSyiene- chloride &dp?dpyl,ether SjSm'oroethylene jSlylichloride jSfT SDeterminations i Formula * C1H4O C,H, NH, CA C,Hio C*Hjq C,H, CtHi CO - GtH.CF C,H,Br C1H1CI C,H, De C,H,C13 C4H10O C.H.0 C1H1O CtHi CjHjBr C1H1CI CjH, ___ GiHioQh H, CH, CH,Br CH.Cl CHjClj CH| C,H, C,H,.0 C1HCI1 CjHiCl -e Lower Ref. no. Upper 4.00 2.80 14.80 2.80 1.85 1.80 1.75 1.76 15.50 4.-506.40 2.80 2.48 4.90 10.00 2.10 3.90 1.85 3.05 6.70 4.05 2.90 ...,2?M... 4.65 5.15 14.00 8.20 ,15,50 2?25-- 2.10 2.20 10.30* 4.00 2 93.0 62 93.0 44 79.0 64 29.9 2 49.0 2 48.0 10 58.3 . 10 55.0 65 93.9 28- 54.0 28 50.0 28 66.0 19 60.0 35 94.7 28 26.0 66 82.0 67 . 61.4 29 85.5 2 66.0 28 44.0 68.. 67.2 68 79.9 .'.26_____ ...jf.76.JL., 2 93.9 2 60.5 28 19.0 69 65.8 70 66,4 71 52.8 28 69,0 72 64.5* 28 70.0 at elevated temperatures. Ref. no.