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Oxygen Physisorption Characteristics of Coal

In different conditions (time, temperature and coal particle size), oxygen physisorption of different coal samples were tested by a oxygen adsorption detection instrument with chromatograph, followed by the analysis of the relation between oxygen physisorption in coal self-heating and the propensity of coal to spontaneous combustion. The results indicate that the physisorption reaches 80% of the saturate amount in several seconds, and then with the rapid decline of the sorption rate takes about 1 min to get saturated. The physisorption decreases with the temperature rise, and increases then drops with decreasing coal particle size, only playing a role in oxygen transportation, physisorption heat generation and the first motivation for coal to self-ignite. The content of oxygen physisorption cannot reflect the capacity of chemisorption and chemical reaction during spontaneous combustion. It is concluded that the sole oxygen physisorption cannot identify the oxidation reactivity of coal effectively.