Supercritical carbon dioxide coal-fired circulating fluidized bed boiler, power generation system and power generation method

Abstract

The invention discloses a supercritical carbon dioxide coal-fired circulating fluidized bed boiler, a power generation system and a power generation method. The supercritical carbon dioxide coal-firedcirculating fluidized bed boiler comprises a hearth, a separator, a tail flue and an externally-arranged type heat exchanger located in a material back section of the separator. A cooling wall and anintermediate-temperature overheater are arranged in the hearth. A high-temperature reheater and a low-temperature overheater are arranged in the externally-arranged type heat exchanger, wherein the low-temperature overheater communicates with the cooling wall and the intermediate-temperature overheater. A low-temperature reheater, a high-temperature overheater, an upper-level economizer, a lower-level economizer and an air preheater are arranged in the tail flue, wherein the high-temperature overheater communicates with the intermediate-temperature overheater, the low-temperature reheater communicates with the high-temperature reheater. The working medium of the boiler is supercritical carbon dioxide. By the adoption of the supercritical carbon dioxide coal-fired circulating fluidized bedboiler, the wall temperature of the cooing wall can be effectively controlled, it is guaranteed that the boiler safely and reliably operates, and the heat efficiency is high; a power generator set tends to be miniature, a higher load response speed is obtained, the deep peak load regulation adaptability is high, the advantages of coal resources are taken into full play, the energy utilization rate is improved, and energy safety is guaranteed.

Description

technical field [0001] The invention relates to a boiler, in particular to a supercritical carbon dioxide coal-fired circulating fluidized bed boiler, a power generation system and a power generation method, belonging to the technical field of clean coal and high-efficiency power generation. Background technique [0002] At present, the primary energy structure dominated by coal determines that the long-term internal coal-fired thermal power generation will still be the mainstream direction in the future. Existing thermal power units have high energy consumption and large emissions of pollutants and greenhouse gases. Critical units are limited by material costs and manufacturing levels, and it is urgent to develop clean and efficient new coal-fired power generation technologies to ensure the sustainable development of the power industry. [0003] Supercritical carbon dioxide has high energy density near the critical point, good flow and heat transfer characteristics, the siz...

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Problems solved by technology

[0005] The supercritical carbon dioxide cycle applied in the field of fossil fuels is mostly aimed at pulverized coal boilers, and a few are aimed at circulating fluidized bed boilers, but the temperature of the cooling wall inlet working fluid of these boilers is very high. ℃ / 28Mpa, the designed cooling wall inlet working fluid temperature is 510℃~530℃; at the same time, the proposed main compressor outlet or low-temperature regenerator high-pressure side outlet of the lower temperature working fluid diverts into the economizer, ensuring In the case of hot air temperature, it will cause a large irreversible loss of the economizer, and the inlet pressure of the compressor is closely related to the exhaust pressure of the turbine, and the system flexibility is low

[0006] The improvement of the efficiency of existing thermal power units mainly depends on the improvement of steam parameters. Steam parameters are limited by the high-temperature strength of materials, high-temperature oxidation and corrosion resistance, and welding and processing technology. 700°C high-strength materials need further research and development, and 700°C supercritical units The final boiler superheater, final reheater, main pipeline, steam turbine high-temperature section and other components need to use expensive nickel-based alloy materials, resulting in increased investment costs and reduced overall economic efficiency. The unit is large in size and low-load operating efficiency Low, unable to meet peak shaving requirements

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