Potential assessment of CCUS source and sink and its matching research of deep unworkable seam in Huainan coalfield of China

Abstract It is of great significance for the engineering popularization of CO₂-ECBM technology to evaluate the potential of CCUS source and sink and study the matching of pipeline network of deep unworkable seam. In this study, the deep unworkable seam was taken as the research object. Firstly, the evaluation method of CO₂ storage potential in deep unworkable seam was discussed. Secondly, the CO₂ storage potential was analyzed. Then, the matching research of CO₂ source and sink was carried out, and the pipe network design was optimized. Finally, this study puts forward suggestions on the design of pipeline network from the perspective of time and space scales. The results show that the average annual CO₂ emissions of coal-fired power plants vary greatly, and the total emissions are 58.7608 million tons. The CO₂ storage potential in deep unworkable seam is huge with a total amount of 762 million tons, which can store CO₂ for 12.97 years. During the 10-year period, the deep unworkable seam can store 587.6 million tons of CO₂, and the cumulative length of pipeline is 251.6129 km with requiring a cumulative capital of 4.26*10¹⁰ dollars. In the process of CCUS source-sink matching, the cumulative saving mileage of carbon sink is 98.7502 km, and the cumulative saving cost is 25.669 billion dollars with accounting for 39.25% and 60.26% of the total mileage and cost, respectively. Based on the three-step approach, the whole line of CO₂ source and sink in Huainan coalfield can be completed by stages and regions, and all CO₂ transportation and storage can be realized. CO₂ pipelines include gas collection and distribution branch lines, intra-regional trunk lines, and interregional trunk lines. Based on the reasonable layout of CO₂ pipelines, a variety of CCUS applications can be simultaneously carried out, intra-regional and inter-regional CO₂ transport network demonstrations can be built, and integrated business models of CO₂ transport and storage can be simultaneously built on land and sea. The research results can provide reference for the evaluation of CO₂ sequestration potential of China's coal bases, lay a foundation for the deployment of CCUS clusters, and promote the realization of China's dual-carbon strategy.