Gases autoignition temperature

Flammable gas autoignition temperature 460°C (860°F) fire-extinguishing measure shut off the flow of gas and use a water spray to disperse the gas and keep fire-exposed containers cool. Isobutane forms explosive mixtures with air the LEL and UEL values are 1.9% and 8.5% by volume of air, respectively. 

Methane An alkane (saturated aliphatic hydrocarbon) with one carbon atom, CH4. A colorless, odorless, highly flammable gas (autoignition temperature, 537°C). Reacts with chlorine in light. Occurs as natural and coal gas. Can be obtained synthetically from a mixture of carbon monoxide and hydrogen from steam treatment of hot coal. Used in petrochemical synthesis, for manufacture of carbon black and chlorinated solvents, and as fuel. 

Propylene An alkene (unsaturated aliphatic hydrocarbon) with three carbon atoms, CH2=CHCH3. A colorless, highly flammable gas (autoignition temperature, 497°C). Derived by thermal cracking of ethylene or from naphtha. Used as monomer in polymer and organic synthesis. Also called Propene. 

Combustion of a flammable gas-air mixture occurs if the composition of the mixture lies in the flammable range and if there is a source of ignition. Alternatively, combustion of the mixture occurs without a source of ignition if the mixture is heated up to its autoignition temperature. 

The autoignition temperature is the minimum temperature required for self-sustained combustion in the absence of an external ignition source. The value depends on specified test conditions. Tht flammable (explosive) limits specify the range of concentration of the vapor in air (in percent by volume) for which a flame can propagate. Below the lower flammable limit, the gas mixture is too lean to burn above the flammable limit, the mixture is too rich. Additional compounds can be found in National Fire Protection Association, National Fire Protection Handbook, 14th ed., 1991. 

Undesirable combustible gases and vapors can be destroyed by heating to the autoignition temperature in the presence of sufficient oxygen to ensure complete oxidation to CO2 and H2O. Gas incinerators are appHed to streams that are high energy, eg, pentane, or are too dilute to support combustion by themselves. The gas composition is limited typicaUy to 25% or less of the lower explosive limit. Gases that are sufficiendy concentrated to support... 

PPS fiber has excellent chemical resistance. Only strong oxidising agents cause degradation. As expected from inherent resia properties, PPS fiber is flame-resistant and has an autoignition temperature of 590°C as determined ia tests at the Textile Research Institute. PPS fiber is an excellent electrical iasulator it finds application ia hostile environments such as filter bags for filtration of flue gas from coal-fired furnaces, filter media for gas and liquid filtration, electrolysis membranes, protective clothing, and composites. 

Propylene is a colorless gas under normal conditions, has anesthetic properties at high concentrations, and can cause asphyxiation. It does not irritate the eyes and its odor is characteristic of olefins. Propjiene is a flammable gas under normal atmospheric conditions. Vapor-cloud formation from Hquid or vapor leaks is the main ha2ard that can lead to explosion. The autoignition temperature is 731 K in air and 696 K in oxygen (80). Evaporation of Hquid propylene can cause skin bums. Propylene also reacts vigorously with oxidising materials. Under unusual conditions, eg, 96.8 MPa (995 atm) and 600 K, it explodes. It reacts violentiy with NO2, N2O4, and N2O (81). Explosions have been reported when Hquid propylene contacts water at 315—348 K (82). Table 8 shows the ratio TJTp where is the initial water temperature, and T is the superheat limit temperature of the hydrocarbon. 

Gas or Vapor Flammability Limits (vol. %) Flash Point rc) Autoignition Temperature rc) Laminar Burning Velocity (mis)... 

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... 

By far the most important sulfide is CS2, a colourless, volatile, flammable liquid (mp — 111.6°, bp 46.25°, flash point —30°, autoignition temperature 100°, explosion limits in air 1.25 50%). Impure samples have a fetid almost nauseating stench due to organic impurities but the purified liquid has a rather pleasant ethereal smell it is very poisonous and can have disastrous effects on the nervous system and brain. CSt was formerly manufactured by direct reaction of S vapour and coke in He or steel retorts at 750 1000°C but, since the early 1950s, the preferred synthesis has been the catalysed reaction between sulfur and natural gas ... 

When pressure-decay rates less than critical are employed, the gas-phase combustion zone is removed from the propellant surface and extinguished, but not the ignition from within the condensed phase. Therefore, the temperature of the surface material will be above the autoignition temperature, and steady-state combustion will eventually be initiated. This mechanism is consistent with the observation that the luminosity of the combustion zone can vanish without combustion having been completely terminated. 

A third approach has been suggested by Jaroudi (Jl), who points out that one necessary condition to prevent reignition of the propellant is to ensure that the gas temperature resulting from thermal equilibrium between the injected fluid and the combustion products is below the propellant autoignition temperature. This approach leads to the conclusion that the ratio of coolant mass flow to propellant mass flow is the critical correlating parameter. 

Autoignition temperature. The autoignition temperature of a gas or vapor is the temperature at which it will ignite spontaneously in air, without any external source of ignition. 

It may ignite in air [1], particularly if air is admitted suddenly into the gas at reduced pressure [2], Although digermane and its homologues do not usually ignite on exposure to air, their autoignition temperatures appear to be about 50°C and combustion is rapid or explosive [3],... 

White phosphorus has an autoignition temperature only shghtly above ambient, dispersed it will soon heat itself to that by the slow oxidation responsible for its glow. Red is not spontaneously combustible, however if it does catch fire white will be produced, so that the fire, once extinguished, may spontaneously re-ignite. Both can produce phosphine, among other products, by slow reaction with water. Sealed containers of damp phosphorus (white is often stored under water) may pressurise with highly toxic, pyrophoric, gas mixtures [1]. 

An approximate mathematical analysis is considered to estimate the functional dependence of the gas properties and vessel size on the autoignition temperature. We anticipate that Tc will be close to 7X, so we write... 

Autoignition Temperature (AIT) - The lowest temperature at which a flammable gas or vapor-air mixture will ignite from its own heat source or a contracted heat source without the necessity of a spark or flame. 

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