Study on combustion characteristics and oxidation kinetics of water-immersed coal under different ventilation rates

Abstract

The sudden air drying of coal samples during long-term immersion in water will increase the risk of coal spontaneous combustion, and then coal spontaneous combustion will occur. Ventilation rate is a key factor affecting coal spontaneous combustion, but its effect on spontaneous combustion of water-immersed coal is not clear. In order to investigate the effect of ventilation rate on the combustion characteristics of water-immersed coal, this paper first tested the cross-point temperature and CO and CO2 release patterns of coal samples during low-temperature oxidation using a programmed heating system, then tested the combustion characteristics of water-immersed coal using a simultaneous thermal analyzer, and finally tested the functional group content of water-immersed coal using infrared spectroscopy. The study showed that: the cross-point temperature of the coal sample was the lowest when the ventilation rate was 60 mL/min, but the release of CO and CO2 increased with the increase of ventilation rate; the optimal ventilation rate existed in the coal combustion process, when the activation energy of the coal was the smallest, and the coal burned more easily and released more heat; the higher the ventilation rate, the more oxygen-containing functional groups such as carbonyl and carboxyl groups were contained in the coal, which provided the coal oxidation sufficient energy source for coal oxidation.

Keywords

• water-immersed coal
• combustion characteristics of coal
• spontaneous combustion
• ventilation rate
• cross point temperature