Decrease of Calorific Value in Coal of Oxidation

Abstract

Low temperature oxidation of coal is influenced by various factors such as temperature, time, degree of oxidation, particle size, velocity of ventilation and so on.This paper is concerned with the measurement of changed weight of coal caused by oxidation of low temperature using the weight method of thermobalance, and considers macroscopic mechanism of the formation and decomposition velocity of products due to sorption of oxygen.On the other hand, the measurement is performed on the temperature rise by weight of produced gas and sorption of oxygen with the measuring apparatus of adiabatic type and an estimating method of calorific value in low temperature oxidation of coal is formulated.For the elucidation of the decrease of calorific value and the temperature rise in the coal storage pile, distribution of wind pressure against the sloping surface and air resistance and its flow appearance in this pile are investigated. On the basis of this investigation, distribution of velocity of ventilation is estimated and after its application to the estimating method, the decrease of calorific value and the temperature rise are obtained and these are compared with the practical measurements.