This project belongs to the field of energy and power technology. Expanding the scope of energy use, especially low-grade energy that is difficult to utilize, reducing the release of low-grade energy and efficiently and rationally utilizing it are the core issues and technologies of concern in this field. Against the background of the continuous emergence of contradictions between energy supply and demand, how to increase energy supply and reduce consumption is a hot issue of concern to today's society. This project focuses on expanding energy supply and effective utilization, especially carrying out a series of research on the efficient utilization of low-grade fuels with a wide range of areas, and has achieved research results that can meet actual production needs. Low-grade fuels come from a wide range of sources, but their utilization rates are low. A considerable number of types of low-grade fuels will be produced in the production processes of metallurgy, coal processing, chemical industry, petroleum smelting and other industries, such as blast furnace gas, converter gas, CRG gas, etc. Due to their low calorific value and large differences in properties, it has so far been difficult to utilize them on the same equipment. Therefore, how to rationally and efficiently utilize this energy source, research and develop the exchange and stable combustion of multiple types of low-grade fuels, and effective utilization on the same equipment are the key technologies studied in this project. Aiming at this key technology, this project has studied the technology and development trends in the utilization of low-grade fuels at home and abroad, single fuel exchange theory and combustion technology. On this basis, after research, it has proposed an exchange theory suitable for multiple types of low-grade fuels., developed adaptive stabilization technologies and efficient utilization equipment for multiple types of low-grade fuels, formed independent intellectual property rights, and integrated innovation has achieved efficient and adaptive stabilization of multiple types of low-grade gaseous fuels on the same energy-using equipment. The application scope of multiple types of low-grade fuels has been expanded, and operation optimization software for multiple types of low-grade fuel supply systems has been developed based on the operating characteristics of multiple types of fuel supply systems to guide the actual production process and achieve good economic benefits. Key innovations: (1) Through the research on the exchange theory of multiple types of low-grade fuels, an exchange theory suitable for multiple types of low-grade fuels was proposed, calculation methods and software for exchange indicators and combustion characteristics were developed, and experiments were carried out based on the exchange theory. The scope of fuel exchange has been determined, the application scope of multiple types of low-grade fuels has been expanded, and the purpose of replacing high-grade and high-quality fuels with multiple types of low-grade fuels has been achieved. (2) Various types of adaptive stable combustion devices and low-pollution methods and technologies for low-grade fuels have been developed, and two national invention patents have been authorized: ① Various types of stable combustion methods and devices for high and low calorific value gas (ZL200810039413.5); Reburning burners and application methods (ZL200810038040.X). Efficient utilization and exchange of multiple types of low-grade fuels on the same energy-using equipment have been achieved. (3) An operating coupling model for multiple types of low-grade fuel supply systems has been established. According to the changing laws of enterprise production capacity and energy consumption, the fuel supply system has been optimized and the operating mode has been scientifically predicted to optimize the operation of multiple types of low-grade fuel supply systems. Efficient balance strategy allows each energy-using equipment to operate in an efficient state, which is conducive to reducing energy consumption. (4) Research and develop operation optimization software for multiple types of low-grade fuel supply systems, establish dynamic balance relationships for the fuel supply systems, and use the operation optimization software to obtain optimal ratios for multiple types of fuel supply systems, allowing enterprises to make full use of a large number of low-grade fuels. The results of this project have been applied to the gas boilers of Baoshan Iron and Steel Co., Ltd. and its subsidiaries. It has successfully replaced high-grade fuels with various types of low-grade fuels. It has actually saved 2% of the total consumption of coke oven gas and reduced pollutants. NOx and CO2 emissions have significant benefits both economic and social. Since then, it has been successfully promoted and applied to soaking pits, thick plate heating furnaces and ring furnaces, and achieved a total of 24.9184 million yuan in economic benefits from 2010 to 2012.