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Zhonghe Gasification: Promoting the Gradual Utilization of Coal – Signing a Contract for the Incineration of Residual Carbon. Author/Source: Zhongke Hefei Gasification Technology Co., Ltd. Date: 2021-05-31. Clicks: 8. Gradual utilization of coal: Recently, Zhongke Hefei Gasification Technology Co., Ltd. (hereinafter referred to as “Zhonghe Gasification”) entered into a contract with the Engineering Technology Branch of Xi’an Shanggu Power Co., Ltd. for the incineration of residual carbon derived from the gasification fly ash produced by Henan Linzhou Fengbao Pipe Industry Co., Ltd. Gasification fly ash is a solid waste generated during coal gasification. It features extremely fine particle sizes, high ash content, and very low volatile matter levels, making it difficult to ignite and burn completely. Conventional combustion techniques are not suitable for handling it; as a result, it is usually disposed of by direct landfilling or utilized at low costs. This not only occupies large amounts of land and causes soil damage but also prevents the recovery and reuse of the carbon residue present in the fly ash. As environmental regulations become increasingly stringent, the disposal of gasification fly ash has become one of the bottlenecks restricting the development of coal gasification. Both fluidized bed and gasized bed gasification technologies generate gasification fly ash with a certain calorific value. Over the next 2-3 years, the production volume of such fine ash will reach 100 million tons per year. Gasification fly ash has a high carbon content (30%~50%) and a high calorific value (2000~4000 kcal/kg). Further combustion of the unburned carbon in this ash can improve the overall energy efficiency and economic viability of coal gasification systems, while also bringing about positive environmental and social benefits. This residual carbon combustion disposal project utilizes the gasification fly ash combustion power generation technology independently developed by the Circulating Fluidized Bed Laboratory at the Institute of Engineering Thermophysics, Chinese Academy of Sciences. Relying on the strategic pilot science and technology project of the Chinese Academy of Sciences titled “CFB reburning technology for gasified ash and fine powder ash, as well as high-temperature steam generation technology,” the R&D team focused on the fine powder ash and gasified ash separated after coal gasification. They developed a technology for utilizing residual carbon in combustion, using the heat generated from this combustion to produce high-temperature, high-pressure steam for power generation, thereby achieving clean and efficient hierarchical utilization of coal. This technology overcomes the challenges associated with fluidizing and circulating ultra-fine solid materials, as well as those related to the stable ignition, combustion, and complete burning of ultra-low volatile carbon-based fuels. It enables the efficient and clean combustion of gasification fly ash, offering advantages such as the ability to handle large amounts of fly ash, high steam parameters, high combustion efficiency, and significant waste reduction. This technology can also be applied to the disposal of other carbon-based solid wastes. The project will result in the construction of a 75 t/h circulating fluidized bed boiler; once operational, it will enable cogeneration of heat and electricity from coal, making the most of the coal used and thus contributing effectively to energy savings and emission reduction.