Research on coal safety range and green low-carbon technology path under the dual-carbon background

Coal is a main energy and an important raw material in China, which has made a historically indelible contribution to the great rejuvenation of the Chinese nation, and will play an indispensable role in the future, especially in promoting China's energy transformation and development. As the main target of "dual carbon" (carbon dioxide emission peak and carbon neutral) goal, the carbon reduction in the energy industry is the key direction of China's "dual carbon" task. Due to the current China's coal-dominated energy situation, on the basis of ensuring energy security, the reduction of total coal consumption and carbon emission intensity is an inevitable choice to achieve the "dual carbon" goal. At present, some new requirements have been put forward by the "dual carbon" goal in terms of the overall technological development and the research directions for the coal industry. The coal industry needs science and technology innovation more than ever before. It needs to use a systematical thinking, coordinate the future coal science and technology development path as a whole from several aspects, and comprehensively promote the further development of a new strategy of energy security. Also, it needs to explore a technological path to promote the transformation and upgrading of coal consumption based on scientific determination of quantity, green improvement of quality, and innovation for leading-the-way. This paper expounds the urgency of carrying out research on coal safety range, analyzes the factors affecting the upper and lower limits of safety range, and puts forward the scientific proposition that coal safety range needs to be studied. In addition, the paper summarizes the development of green and low-carbon coal technologies since the founding of the People's Republic of China and expounds the theoretical, technological and industrial application progresses of green and low-carbon development in the five stages of coal industry, viz. pioneer and development, development and reform, establishment of clean coal technology framework, clean and efficient utilization of coal, and high-quality development of coal, etc. Also, the paper analyzes the development of green and low-carbon science and technologies in some major coal producing and consuming countries including China. The analysis reveals the shortcomings in the development of China's coal science and technology innovation under the "dual carbon" background and the need for scientific and technological breakthrough. In terms of four types of green and low-carbon technological development, namely technological upgrades, low-carbon integration, disruptive breakthrough and negative carbon sequestration, the paper proposes some research and development directions, i.e., intelligent green mining, clean and low-carbon utilization, coal mine gas drainage and utilization, ecological restoration of mining areas + carbon sink, coal mine space development and utilization, green hydrogen (electricity) and coal conversion integration, collaborative utilization of coal and biomass/waste, comprehensive utilization of geothermal resources, integration of underground fluidized mining and conversion, coal-based high-energy fuel synthesis, advanced coal-based carbon material preparation, deep in-situ CO2 and CH4 hydrogen production, CO2 storage in closed or residual sections and goaf of coal mines, CO2 flooding oil and gas, electrochemical catalytic conversion of CO2 for capture, and CO2 mineralization and utilization. It provides some lessons for the decision-making of relevant scientific and technological policies for the green and low-carbon transformation development of coal under new circumstance. It is of great significance to guide the coal industry to adapt to the new situation of energy revolution, meet the new requirements of high-quality development of the industry, and seize the new opportunities of adjustment on world economy and energy structure. © 2022, Editorial Office of Journal of China Coal Society. All right reserved.