Acetylene heating value

ACETYLENE. [CAS 74-86-2]. CH CH formula weight 26.04, mp — 81.5°C, bp —84 0, sp gr 0.905 (air = 1.000). Sometimes referred to as ethyne, ethine, or gaseous carbon (92.3% of the compound is C), acetylene is moderately soluble in H2O or alcohol, and exceptionally soluble in acetone (300 volumes of acetylene m 1 volume of acetone at 12 atmospheres pressure) The gas burns when ignited in air with a luminous sooty flame, requiring a specially devised burner for illumination purposes. An explosive mixture is formed with air over a wide range (about 3 to 80% acetylene), but safe handling is improved when the gas is dissolved in acetone, The heating value is 1455 Btu/ft--1 (8.9 Cal/nr). 

For constituents undergoing cracking reactions that release heat, the heating value of the fuel is carbon energy, plus hydrogen energy, plus the heat of formation. Thus, the low heat value of acetylene is ... 

For an industrial gaseous fuel (e.g., natural gas, syngas, producer gas and water gas) containing carbon monoxide, hydrogen, methane, ethane and acetylene, the high and low heating values can be calculated with the following two equations based on the volume or mole fraction of each gas ... 

One of the interesting properties of PBPCP [187] was its fast heat dissipation characteristics and so it was tested by the well-known oxy-acetylene panel test (ASTM 285-70) for ablative materials. Figure 13 shows the survival of a flower for 100 s. kept on the 6.35-mm asbestos fiber-reinforced hexamine-cured panel. The ablation rate value of this material was 3.2 x 10 in/s in comparison with 3.6 x 10 in/s for asbestos-phenolic. As the char content of PBPCP was only 27% compared with 60% for conventional phenolics, mechanisms involving transpiration processes rather than heat blocking by char formation might be playing a greater role in this case [188]. 

If a temperature is desired at an equivalence ratio other than that listed, it is best obtained from a plot of T versus for the given values. The errors in extrapolating in this manner or from the graph are trivial, less than 1%. The reason for separate Figs 1.4 and 1.5 is that the values for = 1.0 and 4> = 1.1 overlap to a great extent. For Fig. 1.5, = 1.1 was chosen because the flame temperature for many fuels peaks not at the stoichiometric value, but between = 1.0 and 1.1 owing to lower mean specific heats of the richer products. The maximum temperature for acetylene-air peaks, for example, at a value of = 1.3 (see Table 1.2). 

The [YCo] systems catalyze this reaction only above 130°C, and hence, the reaction must be carried out in dilute benzene or toluene solutions to keep the TON values below —500. Only very active catalysts can be used for the reaction of Eq.(13) when carried out in pure acrylonitrile. Every cobalt catalyst sufficiently active below 125°C was tested in a batch reactor. A solution of the catalyst in pure acrylonitrile was saturated with acetylene at —2.0 MPa and then heated to 130°C (for experimental procedures, see 84MI5). The TON values after 2 hrs are summarized in Table II. The best results were obtained with the i7 -phenylborininato complex (9), which produced 2.78 kg VP/g Co. 

CH2 CH.C=C)2Hg, C8H6Hg mw 302.73 dark at 0°, becomes a yel solid at RT mp 144-45°, 142.0—0.5° (separate values) v sol in chlf. Prepn is by reacting vinyl acetylene with Hg oxide in acetic acid at RT. The salt explds when heated or struck... 

C2H2 (liq.). Acetylene does not exist as a liquid at a pressure of 1 atmosphere. Vapor pressure data on liquid acetylene were obtained by McIntosh,1 Cardoso and Baum,1 Kuenen,2 Villard,1 Ansdell2 Laden-burg and Krugel,2 Hunter,1 and Cailletet.1 McIntosh1 reported a value for the heat of vaporization at the triple point, —81.5°. 

In Tables 10 to 12 we show the heats of formation calculated by the various methods, together with their deviation from the experimentally observed values for alkanes and cycloalkanes, alkenes and cydoalkenes, and acetylenes and aromatic compounds. Table 13 shows a comparison of heats of formation of hydrocarbon radicals calculated by the MINDO methods. Finally, in Tables 14 and 15 we show the results of MINDO/1 calculations on a selection of oxygen- and nitrogen-containing compounds. 

For the heat of formation of a reactant to affect the performance, it must have a value greater than +0. 5 kcal/gm to increase the performance noticeably or a value less than -0. 5 kcal/gm to decrease it. There are very few compounds indeed that meet these requirements, ozone (+), ammonia (-), and acetylene (+),... 

This amount of heat will be the heat, q, used in Equation 17.4. However, because the heat lost by the acetylene will equal the heat gained by the water, the value of q will need to be changed to positive in Equation 17.4 ... 

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