Acetylene-air mixtures

Several studies of spherical and cylindrical detonation in acetylene—oxygen and acetylene—air mixtures have been reported (82,83). The combustion and oxidation of acetylene are reviewed extensively in Reference 84. A study of the characteristics and destmctive effects of detonations in mixtures of acetylene (and other hydrocarbons) with air and oxygen-enriched air in earthen tuimels and large steel pipe is reported in Reference 81. 

Flame arresters for acetylene-air mixtures with a flame-arresting element of sintered metal are available from Western Enterprises of Westlake,... 

One experiment (Moen et al. 1985) revealed that jet ignition of a lean acetylene-air mixture (5.2% v/v) in a 4-m-long, 2-m-diameter bag can produce the transition to detonation. 

A deflagration-detonation transition was first observed in 1985 in a large-scale experiment with an acetylene-air mixture (Moen et al. 1985). More recent investigations (McKay et al. 1988 and Moen et al. 1989) showing that initiation of detonation in a fuel-air mixture by a burning, turbulent, gas jet is possible, provided the jet is large enough. Early indications are that the diameter of the jet must exceed five times the critical tube diameter, that is approximately 65 times the cell size. 

As far as flame composition is concerned, it may be noted that an acetylene-air mixture is suitable for the determination of some 30 metals, but a propane-air flame is to be preferred for metals which are easily converted into an atomic vapour state. For metals such as aluminium and titanium which form refractory oxides, the higher temperature of the acetylene-nitrous oxide flame is essential, and the sensitivity is found to be enhanced if the flame is fuel-rich. 

Burning, Laminar, of Gases. Influence of pressure and temperature on the laminar burning velocity of stoichiometric acetylene-air mixtures using a constant-volume bomb method is described by M.L. Agrawal S.P. Sharma in UnivRoorkeeResJ(India), 8(3-4), Part 11, 81-102(1965) (in Engl)... 

Cook (Ref 16, p 143) in discussing the existence of free electrons in combustion flames and gaseous detonations (first mentioned in 1893 by Turpin and then theoretically discussed in 1909 by J.J. Thomson), quoted the paper of Bone et al (Ref 3), who stated that A.E. Malinovskii et al observed in 1924 the presence of free electrons during detonations of benzene-air mixtures and later (1930 8t 1933) of methane-, ethylene-, and acetylene-air mixtures. Bone et al confirmed Malinovskii s results in the case of spinning detonation of a moist 2CO +O2 mixture (Ref 16, p 143)... 

Acetylene-Air Mixtures. Various CaHa—air mixtures were detonated in rubber balloons by means of central elec detonators. Photographs of spherical explosions thus produced were made with a rotating-drum camera and with a 6000-frame-per-sec movie camera. 

Flanged joints are not permissible for combustible acetylene-air mixtures... 

Figure 6.148 Ion current I and flame resistance R of a 9.3% (v/v) acetylene-air mixture. p = explosion pressure DC field strength 1.25kV/cm ( Ll = 600 V).

This MESG value refers to the hydrogen-air mixture. Acetylene-air mixtures show somewhat higher MESG values, see Table 1.6... 

In the acetylene black process the tubular reactor only has to be heated once to 800°C by the combustion of an acetylene/air mixture. The pyrolysis reaction is then carried out with pure acetylene, which proceeds strongly... 

Experimental studies within the PNP gas cloud program were conducted and evaluated by the Fraunhofer Institute for Chemical Technology using flammable mixtures of hydrogen and other fuels with air in different shapes (sphere, hemisphere, tube), confined or unconfined. They are described in more detail in section 8.5.2. Experimental results from other test programs in the USA (explosion series in FLAME ) or Norway (jet ignition with transition to detonation in acetylene-air mixtures) were also taken into account. All tests were close to the go - no go boundary between deflagration and detonation. 

The reaction between supported silver nitrate and acetylene-air mixtures in the presence of oil and water vapor has been studied in detail by Krieger (6), using the conditions described earlier for screening tests,... 

Figure 7.15a, b present, in detail, the effect of hydrogenous mixture composition and pressure on the detonation cell size [18, 19]. Besides, Fig. 7.15b compares HAM cell sizes with the same parameter for propane + air and acetylene + air mixtures. 

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