Conception of "coal-based solid waste-CO₂" cooperative filling and storage technology under the target of carbon peak and carbon neutral

The proposal of the "carbon peak and carbon neutral" goal puts forward new challenges and new requirements for the green and low-carbon development of the coal industry. In this study, aiming at the requirements of "coal-based solid waste-CO₂" double near-zero emission in the whole life cycle of coal development and utilization, by exploring the carbon emission sources in the process of coal development and utilization, combined with the existing filling mining technology, a collaborative filling and storage technology concept with "coal-based solid waste-CO₂" near-zero emission as the core was proposed to realize the "internal closed-loop digestion" of coal mining and "coal-based solid waste-CO₂" filling and storage. Based on the relevant results of the author's refuse zero-emission research team, three types of functional filling materials were proposed. Among them, the first and second types of filling materials can control the movement of overlying strata and construct filling units, forming a CO₂ underground storage space with coal seam floor, filling mass, coal pillar and overlying roof as the boundary and geological cover as the final barrier. The third type of filling materials can chemically react with CO₂ to realize the mineralization and storage of CO₂. Based on this, the key problems of "coal-based solid waste- CO₂" collaborative filling and storage were analyzed: evaluation of coal seam occurrence geological conditions CO₂ storage space stability control; estimation of CO₂ storage capacity; monitoring and control of CO₂ charging effect; CO₂ storage safety risk emergency treatment. The proposal of this concept can provide new ideas for the low-carbon and green development of Chinese coal industry.