Study on the composition and structure of foamed gel for fire prevention and extinguishing in coal mines

摘要

The spontaneous combustion of coal in coal mine gob remains a serious threat to workers' safety, and the present work examined the use of foamed gel to prevent coal ignition. A foamed gel is a polymeric substance consisting of foam agent, gelling agent, cross-linker and water. Gelation time, foaming multiple and water loss are key factors to evaluate the fire suppression properties of these materials. The experiments in this study demonstrated that the optimum volume fractions of the foaming, gelling and cross-linking agents were 0.5%, 2%, and 1% respectively. The average gelation time of the foamed gel was 174 s, the foaming multiple was 5.4, and the water loss of the foamed gel over 10 min was 11%, which was significantly less than the value of 91% for pure foam. 3D-X ray experiments showed that foamed gel has similar structure as pure foam, and gel skeleton could maintain the intact of foamed gel, enhance the stability, and increase heat capacity. Compared to pure foam, the foamed gel examined in this study exhibits superior fire prevention performance. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.