The new way for realizing carbon neutrality of coal and analysis of bearing characteristics and stability of coal pillar in production.

In this paper, the idea of Underground coal gasification coupled with supercritical carbon dioxide storage is proposed based on the problems of Underground coal gasification combustion area and carbon dioxide storage site, which provides a new technical approach for carbon peaking and carbon neutrality in the coal sector. At the same time, to solve the underground coal pillar design problem in the popularization and application of UCG-CCS, this paper adopts numerical simulation and theoretical analysis methods to reveal the deformation mechanism and bearing characteristics of "hyperbolic" type coal pillar in UCG-CCS. The results of this study are as follows: ① The injection of supercritical CO 2 into the underground goaf can effectively reduce the load of the coal pillar bearing the overlying strata and improve the bearing capacity of the "hyperbolic" protective coal pillar. ② The size of the "hyperbolic" coal pillar in UCG-CCS slightly influences the coal pillar's stability under certain injection pressure. For safety in practical engineering, it is necessary to ensure that the CO 2 injection pressure reaches its critical pressure of 7.38 MPa. ③ Based on numerical simulation results, when the width of the combustion cavity is 40 m, the width of the protective coal pillar is 56 m, the injection pressure of supercritical CO 2 is 7.38 MPa, and the sealing depth ranges from 800 m to 1200 m, the protective coal pillars are in a stable state due to the pressure effect of supercritical CO 2 on the coal pillar and the roof. The research results of this paper have important practical significance for promoting the site selection, product design, and application of UCG-CCS and provide a technical means for the coal industry to achieve carbon peak and carbon neutrality. [ABSTRACT FROM AUTHOR]