Recently, CAS Hefei Coal Gasification Technology Co., Ltd. (ZHGAS) signed an EPC contract with Xinjiang Tianye Huihe New Materials Co., Ltd. for the boiler section of a 490,000-ton/year carbon-based solid waste resource utilization and waste heat/waste pressure recovery project. This marks ZHGAS’s first gasification slag disposal project based on entrained-flow gasification and signifies a major step forward in the industrial application of ZHGAS’s residual carbon utilization technology.
Xinjiang Tianye Huihe's 600,000-ton/year Phase I ethylene glycol project uses the Jinhua gasifier to produce syngas, generating large volumes of gasification slag annually. This slag is characterized by high moisture content, ultra-fine particle size, high carbon and ash content, extremely low volatile matter, and moderate calorific value. It is typically handled through direct landfilling or low-value use, which not only consumes large land resources and causes environmental degradation but also leads to significant energy waste due to unutilized residual carbon.
To address the specific needs of the project and the characteristics of the slag, ZHGAS engineers have designed a circulating fluidized bed (CFB) combustion system for its disposal. The dewatered slag can be fed directly into the combustion system without drying to produce steam, achieving staged utilization of coal. Upon commissioning, the project will enable a tri-generation system of gas, heat, and power, maximizing coal resource utilization and significantly improving energy efficiency and emissions performance.
The CFB combustion technology adopted in this project was developed by the CFB Laboratory of the Institute of Engineering Thermophysics, Chinese Academy of Sciences (CAS). Backed by the CAS Strategic Priority Program on “CFB Reburning Technology for Gasification Ash/Fine Fly Ash and High-Temperature Steam Generation,” the research team focused on combustion of fine ash and gasification slag separated from coal gasification systems. The technology overcomes key challenges such as fluidization and circulation of ultra-fine solids, and stable ignition and burnout of ultra-low volatile carbonaceous materials. It enables efficient and clean combustion of gasification slag, offering advantages such as high throughput, high steam parameters, high combustion efficiency, and significant volume reduction. The heat from slag combustion can be used to generate high-temperature, high-pressure steam for power generation, achieving clean and efficient staged utilization of coal. This technology can also be applied to other types of carbon-based solid waste.
With the deepening of China's “dual carbon” (carbon peaking and carbon neutrality) policy, comprehensive utilization of gasification residues has become a key challenge restricting the sustainable development of coal gasification. Both entrained-flow and fluidized-bed gasifiers produce fine ash residues with significant calorific value. In the next 2–3 years, the annual output of gasification fine slag in China is expected to reach 100 million tons. This fine ash typically contains 30–50% unburned carbon and has a calorific value ranging from 2,000 to 4,000 kcal/kg. Efficient combustion of this residual carbon can greatly improve the overall energy efficiency and economic performance of gasification systems while creating substantial environmental and social benefits.
About Xinjiang Tianye Huihe New Materials Co., Ltd.
Xinjiang Tianye Huihe New Materials Co., Ltd. was established on July 12, 2017, and is majority-owned by Xinjiang Tianye (Group) Co., Ltd. Founded in July 1996, Tianye Group is a large state-owned enterprise under the Eighth Division of the Xinjiang Production and Construction Corps. The Group’s business spans thermal power, chemicals, calcium carbide, cement, mining, building materials, logistics, international trade, and construction.
Tianye Huihe is responsible for the development and operation of the 1 million-ton/year syngas-to-low-carbon alcohol project. The first phase—an annual 600,000-ton syngas-to-ethylene glycol plant—broke ground in August 2017 and was commissioned in August 2020, with a total investment of RMB 7.997 billion. Covering 2,250 mu of land, it is the first project built in the northern section of the Shihutanzhen New Materials Industrial Park.
