Effectiveness of catechin and poly(ethylene glycol) at inhibiting the spontaneous combustion of coal

• We studied the influence of catechin and PEG on retarding coal oxidation.
• A suppression mechanism of the additives was suggested.
• In situ monitoring of coal surfaces during oxidation was studied.

The effects of various combinations of catechin and poly(ethylene glycol) (PEG) concentrations on the inhibition of coal oxidation were studied. The oxidation behaviors of coal samples both with and without the additives were examined, based on measurements of cross point temperature, oxygen consumption during low temperature oxidation and carbon monoxide emission rates. The results demonstrate that an additive consisting of a combination of both catechin and PEG 200 is capable of inhibiting the oxidation process. In situ monitoring of the surfaces of coal samples during oxidation also indicated that these additives suppress coal oxidation by accelerating the formation of ether bonds. Accordingly, a suppression mechanism is proposed.