Coal ignition temperature

Occurrence. Carbon monoxide is a product of incomplete combustion and is not likely to result where a flame bums in an abundant air supply, yet may result when a flame touches a cooler surface than the ignition temperature of the gas. Gas or coal heaters in the home and gas space heaters in industry have been frequent sources of carbon monoxide poisoning when not provided with effective vents. Gas heaters, though properly adjusted when installed, may become hazardous sources of carbon monoxide if maintained improperly. Automobile exhaust gas is perhaps the most familiar source of carbon monoxide exposure. The manufacture and use of synthesis gas, calcium carbide manufacture, distillation of coal or wood, combustion operations, heat treatment of metals, fire fighting, mining, and cigarette smoking represent additional sources of carbon monoxide exposure (105—107). 

An improved method for determining the AIT of solids has been described, and the effect of catalytically active inorganics on the reactivity and ignition temperature of solid fuels has been studied. Sodium carbonate markedly lowers the ignition temperatures of coal and coke [7], The volume of the vessel (traditionally a 200 ml flask) used to determine AIT has a significant effect on the results. For volumes of... 

Gas and Coal Dust Explosion. Title of a series of papers published by K. Mat sumo to in J Minin gins t Japan 68, 260—5 379—82 (1952) 8t CA 48, 3691 (1954). The papers include adsorption of mine gases by the coal dusts heat of adsorption of mine gases by coal dusts and ignition temperature of the coal dusts... 

Sulphur dust is more dangerous than coal-dust, because of the low ignition temperature of sulphur suspensions in air. According to Dubnov [53] 100 g charges of the U.S.S.R. explosives Ammonit No. 1 and 8 ignited sulphur dust. The same explosives did not ignite a methane-air mixture when the quantities were 400 and 500-650 g respectively. In sulphur mines explosives of very low detonation temperature should be used. 

Coal gas or LPG does not start to burn at ordinary temperatures. Kerosene also has a high ignition temperature. 

If this heat raises the temperature of the air to more than the ignition temperature of coal, the coal dust bursts into flames, on its own. 

Combustion Rate of Carbon—Eq (12-18) can hardly be expected to hold at ignition temperatures. Indeed it is doubtful whether it will hold at temperatures much above 400 deg C even in the case of anthracite coal. Above this point the carbon ignites and a completely new set of conditions pertains to the problem. Studies on the combustion rate of carbon particles have been studied in considerable detail by several investigators. The general method used was described by Parker and Hottel (1936). The device used consists of a furnace in which is suspended a cylindrical rod of carbon 2.5 cm in diameter with a hemispherical end. The rod is mounted on a porcelain tube and suspended from one arm of a balance so that the hemispherical end is downward in the furnace. In this way loss of weight is easily determined. The surface of the specimen is also capable of measurement. Known volumes of air heated to the required temperatures are then made to flow past the carbon, and by means of a small quartz sampling-tube (which can be adjusted at any distance from the specimen) samples are withdrawn for analysis. In this way samples of air may -be analyzed for the amount of carbon dioxide and oxygen present at any distance from the heated particle-surface. 

The importance of the subject, particularly in connection with hydrocarbons, will be evident when its bearing upon explosions in coal mines is remembered.2 Of modem methods of determining ignition temperatures, the following deserve consideration ... 

Despite the high ignition temperature of methane-air mixtures of 595°C/650°C (see Table 1.3), the maximum surface temperature is subjected to a very strong limitation with respect to the unavoidable presence of coal dust with relatively low glow temperatures (see Table 1.4)... 

Firedamp-proof electrical equipment (for coal mines) is not subjected to any classification regarding ignition temperature or MESG values. 

Compared with fission reactors, operation of fusion reactors is more complicated because of the high ignition temperatures, the necessity to confine the plasma, and problems with the construction materials. On the other hand, the radioactive inventory of fusion reactors is appreciably smaller. Fission products are not formed and actinides are absent. The radioactivity in fission reactors is given by the tritium and the activation products produced in the construction materials. This simplifies the waste problems considerably. Development of thermonuclear reactors based on the D-D reaction would reduce the radioactive inventory even further, because T would not be needed. The fact that the energy produced by fusion of the D atoms contained in 1 litre of water corresponds to the energy obtained by burning 120 kg coal is very attractive. 

The ignition temperature of the coal samples is about 340°C according to spontaneous combustion characteristics experiments of coal samples of the 065-2 working face in gushan mine. The spontaneous combustion index gas system with CO for main index gas and C2H4 for auxiliary was established when the effective forecasting temperature was below 220°C. 

As observed from Table 1, the ignition temperature T3 of coal samples increased after adding inhibitor when the inhibitor ratio was 1 2, it reached the maximum value on the same coal sample. 

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