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New Approaches for the Clean Conversion and Utilization of Coal Ash: Internationally Leading Technology for the Rotary Pyrolysis of Low-Rank Coal Ash / Author/Source: Modern Coal Chemical Engineering / Date: 2020-05-26 / Clicks: 26. On November 26, 2019, the China Petroleum and Chemical Industry Federation organized a meeting in Beijing to assess the scientific and technological achievements related to the development and application of large-scale industrial rotary pyrolysis technologies for low-rank coal ash. A review committee composed of 9 experts, including Xie Kechang, an academician of the Chinese Academy of Engineering; Yang Qiyeh, an academician of the Chinese Academy of Engineering; Ni Weidou, an academician of the Chinese Academy of Engineering; and Li Hongzhong, an academician of the Chinese Academy of Sciences, listened to the work reports and research reports presented by the project’s implementing units, Shaanxi Coal and Chemical Industry Group Shenmu Tianyuan Chemical Co., Ltd. and Sinochem Engineering Group Hualu Engineering Technology Co., Ltd., as well as the assessment report prepared by the on-site evaluation team. The committee unanimously agreed that this technology has overcome the key pyrolysis techniques and equipment needed for the clean and efficient conversion of low-grade coal powder; it possesses independent intellectual property rights, features significant innovation and strong potential for industrial application, and brings clear economic, social, and environmental benefits. It plays a positive role in promoting the efficient conversion of low-grade coal powder and advancing scientific and technological progress in the field of coal pyrolysis. The overall technology is at the international leading level, and the committee recommended that large-scale industrial demonstrations and widespread adoption be carried out as soon as possible. It is understood that this technology uses low-grade coal powder with a particle size of 0–25 mm as raw material, and carries out pyrolysis in a rotary reactor to produce high-temperature gas oil and upgraded coke powder (upgraded coal). The high-temperature gas oil is processed through ionization to remove dust and tar particles; the tar is sent on to subsequent processes as a raw material for the further processing of coal tar. The high-calorific value gas is used as a main raw material for LNG and various chemical products, while the upgraded coke powder is utilized in the steel industry, power generation, and as a clean fuel for domestic use. Research and development on this technology began in 2012, and over a period of 7 years, a series of challenges were overcome, including equipment amplification, pipeline blockages, high dust content in oil and gas, short operating cycles, equipment coking, difficulties in oil-water separation, large amounts of wastewater, and challenges in wastewater treatment. A total of **56 patents have been obtained, including 12 invention patents and 44 utility model patents. At the end of 2018, Shenmu Tianyuan Chemical Co., Ltd. utilized this technology to build an industrial demonstration plant with an annual capacity of 600,000 tons in the Jinjie Industrial Park in Shenmu, Shaanxi. This plant produces high-quality coke powder as well as products such as coal tar, LNG, and LPG. Together with the coal tar lightweighting production equipment developed based on Tianyuan Company’s patented coal tar technology, a complete industrial technology chain was established, enabling continuous, safe, and stable operation at full capacity. From November 7 to 10, 2019, the China Petroleum and Chemical Industry Federation organized experts to visit Shenmu Tianyuan Chemical Co., Ltd. to conduct a 72-hour continuous operation test on the large-scale industrial rotary pyrolysis system capable of processing 600,000 tons per year. Based on the inspection of on-site operation conditions and the analysis of performance data: the load of this device reached 107.7% of the design value; the yield of pyrolyzed gas was 12.16 wt%, the yield of coal tar was 10.35 wt%, and the yield of upgraded coke powder was 70.0 wt%. The water consumption per unit of product was 0.05 t/t, the overall energy consumption was 0.169 tce/t, and the energy conversion efficiency was 86.31%. The evaluation expert group believes that the overall process flow of this device is reasonable; it improves the quality of coke powder, has a wide range of applications, and can be used for replacing bituminous coal, in power coal blending, as a fuel for blast furnaces in the metallurgical industry, as clean coal, and as an environmentally friendly fuel ； Coal tar is an excellent raw material for advanced processing to produce lightweight fuels, new types of carbon materials, and high-value chemical products ； Pyrolytic gas has high quality and contains many valuable components that can be utilized, making it a raw material for producing LNG, LPG, and for use in the chemical industry. The clean and efficient conversion and utilization of coal based on its different quality grades is a key focus of China’s energy strategy during the 13th Five-Year Plan period, and medium- and low-temperature pyrolysis technology represents an important method for achieving the differentiated utilization and efficient conversion of coal. Currently, in regions rich in coal reserves such as Shaanxi, Ningxia, and Inner Mongolia, a large number of producer enterprises for semi-coke have been established. In the Yulin area of Shaanxi Province alone, there are over 50 producer of semi-coke, with a production capacity of more than 60 million tons – roughly half of the country’s total capacity. The annual production of semi-coke in this region is 35.82 million tons. However, the existing pyrolysis processes mainly use lump coal (with a typical particle size of >20 mm). Most of these processes employ cubic furnaces with small production scales; the large amount of pulverized coal generated from coal mining cannot be processed, resulting in high production costs and certain levels of pollution. It is reported that the demonstration project for the clean and selective utilization of 6.6 million tons per year of coal ash resources (technical transformation and upgrading), which is being carried out in an orderly manner by Shenmu Tianyuan Chemical Co., Ltd., has been included by the Shaanxi Provincial Department of Industry and Information Technology and the Shaanxi Provincial Department of Finance in the \"2016 Provincial Special Fund Plan for Industrial Transformation and Upgrading and High-End Equipment Manufacturing Projects.\"