Propane autoignition temperature

Various types of rapid, adiabatic compressions have caused explosions. With propane at an initial temperature of 25°C, To = 432°K (I59°C) for compression and specific heat ratios of 25 and I.I3, respectively. Assume that now air enters a compressor to bring propane into the flammable range at 5 percent by volume. The mixture then will be mostly air with k = 1.47. The same compression ratio of 25 will elevate the final temperature T2 to 834°K (56I°C), i.e., above the published autoignition temperature of 450°C for propane and perhaps high enough to cause an explosion. 

For straight paraffinic hydrocarbons (i.e., methane, ethane, propane, etc.) the commonly accepted autoignition temperatures decrease as the paraffinic carbon atoms increase (e g., methane 540 °C (1004 °F) and octane 220 °C (428 °F)). 

The torch fiame temperature must be at least as high as the autoignition temperature of a propane-air mixture, which from Table 26-10 isi450. ... 

Propane An alkane (saturated aliphatic hydrocarbon) with three earbon atoms, CH3CH2CH3. A colorless, flammable gas (autoignition temperature, 467°C). Relatively inaetive ehemieally. Obtained from petroleum or natural gas. Used in petrochemical synthesis, as fuel, aerosol propellant, and refrigerant. 

The low toxicity of DME is comparable to that of liquid propane. Comparatively, methanol is toxic upon skin contact and ingestion. Dimethyl ether has a higher autoignition temperature and lower flammability limit than gasoline [61], however. 

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