A significant direction for the clean and efficient use of coal is to promote energy conservation and consumption reduction in coal-fired power units. In recent years, with the development of units towards large-scale and clean technologies, China's thermal power unit parameters, performance, and production have occupied the world's leading position in all aspects, and the main thermal power equipment has basically achieved domestic production. The goals of "carbon peak" and "carbon neutrality" have put forward higher requirements for the clean and efficient use of coal, and to meet the requirements of lower coal consumption thermal power units, it is necessary to continue to promote the performance improvement of domestic thermal power equipment heat-resistant materials and move towards a higher level.

At the recent symposium on promoting the high-quality development of domestic thermal power pipeline, Chen Jinxing, the specially invited vice chairman of the China Energy Research Association, said that it is necessary to strengthen the clean and efficient use of coal, improve China's power equipment industry chain and supply chain autonomy and control ability, and accelerate the construction of a new type of energy system that is clean, low-carbon, safe, and efficient.

The principle of coal-fired power generation can be simply understood as "boiling water", that is, by burning coal to release thermal energy, high-temperature and high-pressure steam is generated to drive the steam turbine to rotate, and then the rotation of the steam turbine drives the generator to rotate to generate electricity. Theoretically speaking, the higher the steam pressure and temperature, the higher the thermal efficiency of the unit power generation, the lower the coal consumption, and the lower the carbon emissions, which means that coal power is cleaner.

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With the continuous progress of material technology and the improvement of thermal power theory, thermal power steam parameters have gone through several development stages of low pressure, medium pressure, high pressure, ultra-high pressure, sub-critical, super-critical, and ultra-supercritical according to different temperatures and pressures. Under the requirements of low-carbon development of coal power, ultra-supercritical technology has become the mainstream in the current coal power field. Higher steam temperature and pressure require better performance heat-resistant materials for support.

Since 2008, China has accelerated the research and development process of high-temperature alloy materials and key high-temperature component manufacturing, intending to completely break the international monopoly of thermal power heat-resistant materials and produce products that are completely independently researched and developed. The National Energy Administration has held work meetings and organized related enterprises to jointly develop key valves for ultra-supercritical coal-fired power units and main steam pipelines, reheating steam pipelines, high-pressure feedwater pipelines, and bypass pipelines for coal-fired power units. According to the domestication work tasks of the four major pipelines, the National Energy Administration has formulated the "Implementation Plan for the Domestication of Large-Caliber Thick-Walled Seamless Steel Pipes for Ultra (Ultra) Critical Coal-Fired Power Units" to further strengthen the organization and coordination of domestication依托工程建设. At present, China has initially achieved the domestication of heat-resistant materials for the four major pipelines, which can meet the needs of 620°C coal-fired units.

With the in-depth advancement of energy green and low-carbon transformation, the research and application of thermal power units with higher temperature and pressure and lower coal consumption have been put on the agenda. However, when the temperature goes above 620°C and the pressure approaches 30MPa and above, the existing domestic heat-resistant materials cannot meet the requirements and have become a key factor restricting the further reduction of China's thermal power coal consumption. To this end, the "14th Five-Year Plan for Scientific and Technological Innovation in the Energy Field" clearly proposes to carry out research on key technologies such as manufacturing, processing, welding, and inspection of 700°C grade high-temperature alloy materials and key high-temperature components for advanced high-parameter ultra-supercritical coal-fired power generation technology.

"To further reduce power plant coal consumption and carbon dioxide emissions, it is necessary to improve steam parameters. The improvement of power plant boiler operating parameters mainly depends on the applicable range of materials used for the boiler." said Liu Zhengdong, an academician of the Chinese Academy of Engineering.

With the efforts of all parties, domestic heat-resistant material technology has made a breakthrough. The Steel Research Institute, Baosteel Group, and Hongrun Nuclear Installation have jointly carried out the engineering technology research and攻关 of G115 large-caliber thick-walled steel pipes and have been successful. In the national power demonstration project launched on August 31, 2023 - the world's first 630°C Datang Yuncheng 2 units of 1 million kilowatt ultra-supercritical reheat coal-fired power generation unit main project, G115 high-temperature resistant steel was applied to the coal power unit for the first time, raising the steam turbine intake steam temperature to 631°C, breaking through the technical barrier of 620°C for similar million kilowatt units, and raising the thermal efficiency of coal-fired units to more than 50%. At the same time, coal consumption was reduced by 14 grams compared to the advanced level of similar units of 270 grams/kilowatt-hour.

In the view of Jiang Haifeng, the deputy director of the Engineering Equipment Department of Datang Yuncheng Power Generation Company, there is still room for further reduction of coal consumption in thermal power plants with the further improvement of domestic high-temperature resistant new material technology in the future. Chen Jinxing suggested that relevant departments should continue to improve the first set of energy technology equipment support policies, promote the demonstration application of major technical equipment; support innovative enterprises to grow into innovation origins, improve support policies and public service systems, and promote the full release of enterprise innovation and entrepreneurship potential.