Autoignition Temperature AIT

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)). 

Some common petroleum materials AITs under normal conditions are listed below  

This principle only applies to straight chain hydrocarbons and is inappropriate if other types of substances are involved (e.g., hydrogen). 

Autoignition temperatures are vitally important for process designs as it is the temperature at which to prevent or eliminate readily available ignition sources, (e.g., operating temperatures of electrical equipment, light fixtures, etc.). 

Recently revised test methods have revealed that nonluminous or barely luminous combustion reactions are occurring where previously it was reported that no combustion activity was occurring based on flame observance. 

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Autoignition Temperature (AIT) The auto ignition temperature of a substanee, whether solid, liquid, or gaseous, is the minimum temperature required to initiate or eause self-sustained eombustion, in air, with no other souree of ignition. 

The niaxiinwn spontaneous ignition temperature (SIT) or autoignition temperature (AIT) is defined as die minimum temperature at wliicli combustion occurs in a bulk gas mixture when die temperature of a flaiiunable gas-air mixture is raised in a unifonidy heated apparatus. The autoignidon temperature represents... 

Where Autoignition Temperature (AIT) = the minimum temperature at which a material begins to self-heat at a high enough rate to result in combustion. Reported in the Data Guide (Figure 7-51) as the temperature in air at one atmosphere. 

Autoignition temperature (AIT) The minimum temperature at which combustion can be initiated without an external ignition source. Combustible materials at elevated temperatures, which ignite upon contact with air, are at or above their autoignition temperature in air. 

Autoignition temperature (AIT) A fixed temperature above which adequate energy is available in the environment to provide an ignition source. 

The autoignition temperature (AIT) of a vapor, sometimes called the spontaneous ignition temperature (SIT), is the temperature at which the vapor ignites spontaneously from the energy of the environment. The autoignition temperature is a function of the concentration of vapor, volume of vapor, pressure of the system, presence of catalytic material, and flow conditions. It is essential to experimentally determine AITs at conditions as close as possible to process conditions. 

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