Combustion characteristics spontaneous

This chapter is concerned mainly with experimental observations and measurements, one purpose of which is to show how the mechanistic structures for hydrocarbon oxidation (Chapter 1) lead to the observed combustion characteristics, and to describe more recent chemical evidence from combustion studies in support of those interpretations (Section 6.5). It also paves the way to the discussion of spontaneous ignition, or autoignition, in spark-ignition engines, in Chapter 7. 

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. 

Yanni Zhang, Jun Deng, Yongfei Jin. The oil bath temperature programmed experimental research of Coal spontaneous combustion characteristics. Safety in Coal Mines 2010 31(4) 7-10. 

A combustion characteristic which appears to be outside the usual range of characteristics is spontaneous combustion. This is the phenomenon of the apparently inexplicable bursting into flame or smoke of some substances such as oil-soaked rags or overalls, oil-soaked lagging, hay and straw. The explanation is simple a slow oxidation of the oil gives off heat with the formation of substances with lower molecular weights which also have lower flash points. As the oxidation continues the temperature of the... 

It has been recognized for many years that exposure of coal to air can significantly alter the processing characteristics of the coal. This effect is more pronounced in lower rank coals and in fact some brown coals will undergo spontaneous combustion at or near ambient temperatures. 

Iron pyrites, pyrite, marquisite, or mundic is the name given to a brass-coloured sulphide of iron to which the formula FeS2 is usually ascribed. It often occurs in coal, and is known by miners as brass or fool s gold. The spontaneous combustion of coal is frequently facilitated by the oxidation of iron pyrites to iron sulphate.6 It often crystallises in cubes, the faces showing striations but a very characteristic form is the pentagonal dodecahedron, usually termed the pyritohedron. Hardness 6 to 6-5 density 4 8 to 5-2. It leaves a greenish or brownish-black streak. 

The modified nonadiabatic method described for the determination of the spontaneous combustion liability of subbituminous coals can yield satisfactory results. However, a more realistic measurement of a coal s self-heating tendency might be obtained through the use of an adiabatic system. In this case, heat derived from the coal oxidation would not be transferred to the surroundings. A spontaneous combustion instrument intended for field or lab/mine applications should be less complex, yet it should be capable of producing data that is reasonably accurate for predicting the self-heating characteristics of coals. 

Refinery Bleach. Various bleaching clays purify and remove color bodies from refined oils. These wastes contain 5% to 35% oil. The characteristics of these materials are such that they will combust spontaneously, which has created problems for disposal in sanitary landfills, as well as at factory locations in some instances, but this condition can be overcome by several methods. The model refinery presented in the previous section will generate about 2500 kg of waste earth per day, of which 570 kg is oil. 

In summary, the performance of the foam material was affected by many factors, such as foaming agent characteristics (the concentration, the kind and its molecular structure), mixed surfactant, salt, temperature, pH, nanomaterials with surface activity and polymers. We should consider to seek ways to improve foam performance according to the mechanism of these effects of factors, and make full use of all the advantages of foam in the field of fire prevention, such as simple preparation, low cost, few resources consumed and so on. It is proved to be an effective way to improve the effect of coal spontaneous combustion. In addition, we can mix it with other fire prevention material, included nitrogen, sediment and gel to make a mixture. Not only can it save resources, but also it is of significant economic value for its better fire prevention performance than single material. 

The ash in coal. The coal ash is a residue when coal sample complete combustion under prescribed condition. It is an important indicator in the study on the characteristics and utilization of coal quality. Coal ash can reduce coal oxidation heat per unit of mass, while the higher the coal ash, the lower the effective yield of carbon, then the more difficult to spontaneous combustion of coal. 

Deng, J. et al. 2011. Fuzzy Clustering and Pattern Recognition of Characteristic Information in Coal Spontaneous Combustion. Journal of Xi an University of Science and Technology 31(5) 505-509. 

Wen, H. et al. 2011. Experiment Research on Effect of Sulfur on Characteristic Parameters of Coal Spontaneous Combustion. Safety in Coal Mines 42(10) 5-7. 

The coal types are mainly brown coal and long flame coal in Cuijiazhai coi mine, there are spontaneous combustion tendency for coal seams, and the coal seams appeared several spontaneous combustion accidents and hazards. To study the release law of poisonous smoke and gas in the course of coal spontaneous combustion in order to prevent mine fire in the mine, experiments are to be done to study burning characteristics of No. 6 coal seam by using the cone calorimeter. 

Based on the characteristic experiment of coal sample in spontaneous combustion, the relation of concentration and temperature of index gas generated in low temperature oxidation combustion was studied. The index gas system of spontaneous combustion was set up with CO, C2H4 subsidiary. The distribution of three zones of spontaneous combustion is determined with the oxygen concentration method. And the result shows that non-ignition zone is 0-15 m, the spontaneous combustion zone is 15-45 m and the suffocative zone is over 45 m. 

Xu C.F. 2010. Experiment Research on the characteristics of 065-2 coal seam spontaneous combustion in the gushan nine. Fuxin Liaoning Technical University. 

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