[Translation] Positive progress has been made in the research, development, and application of technologies for the graded and quality-based utilization of coal

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http://www.mhg114.com/forum.php?mod=viewthread&tid=108347 Introduction: With the increasing constraints imposed by resource and environmental factors, especially the frequent occurrence of heavy foggy weather, the clean and efficient use of coal has been elevated to an unprecedented level as an important part of China’s energy strategy. Innovations in technologies for the classified and quality-based utilization of coal are also advancing at a rapid pace, with positive results being achieved. Coal pyrolysis is a pioneering technology for the graded and quality-based utilization of coal. Based on the requirements of coal particle size for pyrolysis, it can be divided into lump coal pyrolysis technology and pulverized coal pyrolysis technology. In China, vertical furnaces are used for the pyrolysis of lump coal; this technology is mature and is employed on a certain scale in places such as Yulin in Shanxi and Wuhai in Inner Mongolia, with a production capacity of nearly 50 million tons per year. However, the technology is relatively outdated, with the production capacity of each individual unit being less than 100,000 tons per year. Moreover, measures for controlling pollutants are insufficient, resulting in significant environmental impacts. At the same time, with the widespread use of large-scale mechanized coal mining in our country, the proportion of lump coal produced in coal mines is becoming increasingly small (less than 20%). While traditional lump coal pyrolysis faces development bottlenecks, breakthroughs have been achieved in pulverized coal pyrolysis technology. China began researching coal pyrolysis technology in the 1950s. With the support of programs such as \"863\" and \"973\", various technologies for the pyrolysis of coal have been developed: Zhejiang University’s technology for the staged conversion of coal using a circulating fluidized bed, Dalian University of Technology’s solid heat carrier (DG) process, Beijing Collinsda Technology Co., Ltd.’s technology for improving the quality of coal through belt furnaces, the Clean Coal Technology (LCC) process developed through collaboration between Datang Huayin Power Co., Ltd. and China Wuhuan Engineering Corporation, Beijing Shenwu Environmental Energy Technology Group Co., Ltd.’s regenerative heatless rotary bed carbonization technology, Shenhua’s modular solid heat carrier technology, and Guangdong Zhaoqing Shunxin Coal Chemical Technology Co., Ltd.’s technology for the thermal catalytic processing of lignite. All these technologies for the utilization of coal through pyrolysis have now reached the pilot stage, and significant challenges in this field have been overcome to varying degrees. It should be noted that these technologies have failed to achieve large-scale industrialization, largely because coal powder and tar mix easily and stick to the walls of the pyrolysis furnace, causing blockages. In 2014, breakthroughs were achieved in the research on low-temperature pyrolysis and selective utilization of low-rank coal using a rotating bed technology by Henan Longcheng Group, resolving the technical challenges associated with coal powder pyrolysis. Through multi-tube combustion heating technology and dynamic heat exchange between materials and multiple combustion tubes, staged heating of gas via multiple tubes and intelligent, precise temperature control are achieved ； Through an efficient cyclone-special membrane combined separation process, the recovery of solid particles larger than 4 microns and the separation of oil and gas were achieved, addressing the issues of uneven heating of coal material and slow heat transfer in such material ； The problems of oil and gas leakage and air intrusion have been solved through high-temperature rotary dynamic sealing technology. At the same time, through special extraction processes and extractants, the synergistic extraction of oil and phenols is achieved, enabling the pyrolysis wastewater to meet the standards for biochemical treatment. Combined with established biochemical treatment technologies, this approach facilitates recycling and near-zero emissions. According to on-site calibration by the China Petroleum and Chemical Industry Federation, production lines built using this technology, with a single system capable of processing millions of tons of raw coal per year, have been able to operate stably over long periods of time. The yield of clean coal is 71.53%, the yield of coal tar is 11.05%, and the yield of gas is 9.87%; the energy efficiency reaches 90.70% ； The coal classification, quality differentiation, clean and efficient utilization project with a total capacity of 10 million tons per year has been initially completed, serving as an excellent model for the development of such practices in China. Furthermore, in terms of investment costs for technology and equipment, compared to major coal chemical projects, the investment-return ratio and economic efficiency of graded and quality-specific utilization of coal are higher. The costs related to technology and equipment for coal-to-gas and coal-to-oil processes account for over 80% of the total investment, while in projects focused on the graded and differentiated utilization of coal, such technologies and equipment represent 68% of the costs. Moreover, the key equipment in these projects is domestically produced. Compared to coal chemical projects that require investments of over 10 billion yuan, these approaches have lower costs and room for further cost reduction, offering clear economic advantages. Taking Longcheng Group’s low-grade coal rotary bed low-temperature pyrolysis technology for the separate utilization of coal products as an example, research shows that the cost of producing refined oil is 1,944.64 yuan per ton, which is less than half of the cost associated with direct coal liquefaction; the cost of producing LNG is 1.48 yuan per cubic meter, which is two-thirds of the cost of producing gas from coal ； Its investment intensity is only 70 million yuan per 10,000 tons of oil products, whereas the investment intensities for Shenhua and Yitai’s coal-to-oil projects are 139 million yuan and 175 million yuan per 10,000 tons of oil products, respectively. Source: Consulting Center of the China Coal Industry Association; Author: Li Weiming, Ph.D., Associate Researcher at the Institute of Resources and Environment Policy, Development Research Center of the State Council ； Ren Shihua, Institute of Coal Strategic Planning, China National Coal Research Institute