Experimental investigation on the characteristics of XG/GG/HPAM gel foam and prevention of coal spontaneous combustion

Polymer gel foam shows excellent development potential and application prospects in the prevention of coal spontaneous combustion. To reveal the relationship between the characteristics of gel foam and the prevention of coal spontaneous combustion, XG/GG/HPAM gel foam consisting of polymer xanthan gum (XG), guar gum (GG), and polyacrylamide (HPAM) is prepared. The characteristics of gel foam are investigated in terms of microstructure, viscosity, thermal stability, and film-forming. The effects of gel foam on gas products, characteristic temperature, combustion characteristics parameters, and functional groups during coal oxidation are studied. The results show that polymer delays the foam coarsening and improves the foam stability. XG/GG/HPAM gel foam exhibits a slow foam coarsening process, concentrated bubble diameter distribution, shear-thinning behavior, excellent thermal stability, and film-forming properties. Moreover, the inhibition rate of XG/GG/HPAM gel foam on coal is 43.63% higher than that of ordinary foam. XG/GG/HPAM gel foam effectively improves the apparent activation energy of coal, the maximum weight loss rate of the coal is decreased by 7.55%, and the combustibility, combustion stability, and comprehensive combustion index are diminished by 8.50%, 7.64%, and 10.17%, respectively. Simultaneously, XG/GG/HPAM gel foam reduces the oxidation activity of aliphatic hydrocarbons and oxygen-containing functional groups in coal, blocks the chain reaction, and thus inhibits coal spontaneous combustion. The results provide support for achieving efficient fire prevention performance of gel foam.