【Frontiers in HaiChuan Chemical Technology】Nanometer high-entropy ceramic coatings developed by Lanzhou Institute of Chemical Physics underwent energy efficiency testing in a 165MW coal-fired power unit

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Nanohigh-entropy ceramic coatings developed by Lanzhou Institute of Chemical Physics underwent energy efficiency tests in a 165MW coal-fired power plant. 2025-05-13 As China’s coal reservoir, Xinjiang accounts for 40.6% of the country’s estimated coal resources and plays a vital role in ensuring energy supply across the nation. However, the high-alkali coal in Zhundong, Xinjiang, can cause problems such as boiler coking, high-temperature corrosion, tube bursts, high coal consumption, and low thermal efficiency, thereby affecting the safety and economic efficiency of power plant boilers. Conventional methods such as furnace structure modifications, adjustment of combustion parameters, blending in kaolin, and thermal spraying for protection have not truly solved the industry’s challenges. In recent years, the team led by Gao Xianghu from the Low-Carbon Energy Materials Group at the Center for Resource Chemistry and Energy Materials, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, has been conducting research on key technologies for protecting the radiation heating surfaces of large-scale power plant boilers as well as improving energy efficiency, focusing on the high-alkali coal found in Xinjiang. The nanometer-high-entropy protective and energy-saving ceramic coating developed by the team overcomes key technical challenges related to ceramic materials, such as anti-coking properties, resistance to high-temperature corrosion, infrared enhancement, high thermal conductivity, and adjustable thermal expansion coefficient. It also possesses multiple functions such as reducing coal consumption and improving compatibility with different types of coal, making it suitable for use in large-scale peak-shaving power plants as well as other conventional power plants. In 2022, this technology was applied to two 1000MW ultra-supercritical peak-shaving units in China, achieving good results. Recently, with the support of Huaneng Lanzhou Xigui Thermal Power Co., Ltd. and Xi’an Thermal Engineering Research Institute, the team first completed the numerical simulation for a 165MW unit. The results show that the temperature distribution curve of the combustion flue gas inside the square-cut circle boiler follows a normal-parabolic pattern, with higher temperatures in the central combustion area and lower temperatures at the furnace bottom and at the furnace outlet. The highest combustion temperatures are always found between the main combustion zone and the SOFA (Separated Combustion Air) zone; therefore, the key areas for spraying are the main combustion zone and the SOFA zone. Subsequently, the team applied the nano-high-entropy ceramic coating to the entire furnace radiant heating surface in the 165MW unit. The energy efficiency test results conducted by Xi’an Thermal Engineering Research Institute show that, after 5 months of operation in the furnace, no significant coking or high-temperature corrosion occurred in the material. By comparing the measured data before and after spraying, under high, medium, and low loads, the effective heat absorption rate inside the furnace increased by an average of 5.19%, the amount of water used for temperature reduction decreased by 2.6 t/h, the flue gas temperature dropped by 4.5°C, the physical heat loss due to ash and slag decreased by 0.21%, the thermal efficiency of the boiler improved by 0.46%, and the coal consumption per unit of electricity generated decreased by 1.5 g/kWh. A 1000MW coal-fired power unit can save 13,140 tons of coal per year. Furthermore, spraying a nano-high-entropy ceramic coating effectively mitigates the risks of high-temperature oxidation and wear, thereby improving the unit’s adaptability to different coal types. The above results indicate that nano-high-entropy ceramic coatings possess significant anti-coking, high-temperature corrosion resistance, and energy-saving benefits, offering an effective strategy for protecting the furnaces of peak-shaving coal-fired power plants and conventional coal-fired units that use high-alkali coal from Zhundong. The research outcomes of this project will be extended to provinces such as Gansu, Xinjiang, Qinghai, Inner Mongolia, and Ningxia, providing technical support for the transformation of coal-fired power in China into a type of power source that serves fundamental, supportive, and regulatory functions, as well as for the clean and efficient utilization of high-alkali coal in Xinjiang.