Process design for the production of ultra-low ash coking coal

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Ultra-low ash coking coal can be used directly as high-quality domestic fuel (for fireplaces and barbecues), as an additive in the rubber and plastics industries, and as a solid lubricant. This technology is also a fundamental technique for industrial applications such as the production of fine water-coal slurry, coal liquefied oil, coal-based activated carbon, synthetic graphite, high-purity silicon carbide, and coal batteries. Inner Mongolia, Shanxi (Datong), the Northeast region, Shandong and other places have begun to develop and apply this technology, with several projects for the production of ultra-low ash coking coal already in operation. The activated carbon production project (including the production of ultra-low ash coking coal) developed with the involvement of our company by Inner Mongolia Taixi Coal Group has been designated as a high-tech development project by the Inner Mongolia Autonomous Region, and it has been applied for recognition as a **-level high-tech development project. During the design phase of the project, many domestic and international clients came to place orders. It has been in operation for nearly half a year now, running smoothly with good performance. Foreign countries attach great importance to the technology for producing ultra-low ash coking coal; at present this technology is still kept confidential, which is why only a few companies possess the skills to produce high-quality activated carbon for use in medical and drinking water treatment. The technology for producing ultra-low ash coking coal is one of the key technologies in this field. At present, most manufacturers in our country are only able to produce low-value-added products of low quality, on a small scale, facing fierce market competition. As people’s living standards continue to improve, it is foreseeable that the demand for coal-based activated carbon will be very high both domestically and internationally in the future. This product has a high added value, and it aligns with industrial policies aimed at supporting environmental protection and the deep processing of coal, making it an ideal candidate for projects related to the deep processing of coal. 1 Overview Due to the lack of a unified definition for ultra-low ash coking coal, it is temporarily defined as coal that, after washing and processing, has an ash content of less than 2%, and in which harmful substances such as sulfur, phosphorus, and arsenic are present at extremely low levels. If the ash content is less than 0.5% after washing and processing, it is called ultra-pure coal. The ash content of the raw coal in seams 2 and 3 at the Tuoligou Mine and the Gulaben Mine, which are part of the Inner Mongolia Taixi Coal Group, is generally 5%; the inherent ash content of this coal is low, and this is due to the conditions under which these coal seams were formed – a phenomenon that is rare worldwide. At the same time, it features a high recovery rate for low-ash coking coal; when the ash content of the coking coal is 2%, the recovery rate is 65% ； When the ash content of the refined coal is 0.5%, the recovery rate of the refined coal can also approach 40%. Although the production process is complex and energy-intensive, the value of the coal product per ton can be increased by over 2,000 yuan. This production process includes the following key technologies: ① The working principle, safety, energy efficiency, and cost-effectiveness of fine-grinding ； ② Method for sorting ultra-low ash coking coal and determination of process parameters ； ③ Design of the dehydration process flow for fine-grained coking coal ； ④ Thermal and fluid dynamic calculations as well as safety considerations for drying systems. Among them, microbubble flotation and in-solution granulation technologies are globally recognized as key separation technologies to be developed in the coal washing industry in the 21st century. By collecting extensive relevant information and making full use of the technical expertise of domestic equipment manufacturers, research institutions, and universities, in-depth research and semi-industrial trials were conducted on all the key technologies. 2 Fine-grinding: The particle size of the raw coal is < 50 mm; the processing capacity is 10–15 t/h, with an ash content of Ad