Study on gas release behavior and multi-level early warning mechanism of polyurethane and coal co-combustion

In recent years, with the wide application of polymer grouting material in coal mines, fire accidents of polymer materials have occurred occasionally. The traditional early warning gas index of coal spontaneous combustion is no longer suitable for the actual situation of the site when polyurethane and coal (PUF/Coal) are co-fired. In this study, aiming at the problem of unclear gas release pattern of PUF/Coal co-combustion, a combustion model of PUF/Coal was designed based on the actual filling condition. On-line mass spectrometry, SEM and low-temperature CO₂ adsorption were used to explore the release pattern of characteristic gases under the co-combustion system, and to propose the indicators of characteristic warning gases under PUF/coal co-combustion. The results show that adding polyurethane promotes the combustion of coal and reduces the cross temperature of the co-combustion system. The combustion of polyurethane leads to the expansion of micropores and the increase of microcracks in coal, which promotes the rapid release of gases. Based on the generation and oxidation characteristics of these key characteristic gases, we propose a five-level early warning for PUF/Coal co-combustion, which can effectively provide scientific guidance for fire prevention in related industrial applications.