Experimental study on the compound system of proanthocyanidin and polyethylene glycol to prevent coal spontaneous combustion

In order to overcome the short inhibition duration of physical inhibitor, the environmentally friendly chemical inhibitors of polyethylene glycol (PEG) and proanthocyanidin (OPC) were selected to conduct the experimental study for coal spontaneous combustion prevention. Through temperature programmed experiment, electron spin resonance experiment and Fourier infrared spectroscopy experiment, it was found that for the coal sample after treated by PEG and OPC, crossing point temperature increased by 17.6 degrees C and 14.3 degrees C, free radical concentration decreased to 0.1512 N-g/1017 g(-1) and 0.1178 N-g/1017 g(-1), association and hydroxyl free hydroxyl groups decreased by 59.72% and 24.37%, and the stability of the C-O-C ether bond increased by 42.71% and 18.41%, respectively, which showed the inhibition effects of both inhibitors are obvious and OPC is better. For the sample treated by OPC and PEG (ratio 1:2), crossing point temperature increased 25 degrees C, which indicated that the collaborative effect was remarkable. The analysis shows that PEG and OPC contain a large number of hydroxyl groups, which react with the oxide intermediate product alcohol to form ether bonds with relatively stable chemical properties, thus mitigating the rate of coal spontaneous combustion; PEG and OPC are linked by hydrogen bonds to synthesize larger hydrogen proton donors, which improved antioxidant activity. PEG is a viscous liquid, when carrying proanthocyanidin, can cover the surface of coal, isolating coal surface from oxygen, keeping moisture and cooling. The combination of the two inhibitors has significant synergistic inhibition effect, which can greatly suppress the coal spontaneous combustion.