Supercritical carbon dioxide circulation flue gas waste heat recovery coal-fired power generation system and operation method

Abstract

The invention discloses a supercritical carbon dioxide cycle flue gas waste heat recovery coal-fired power generation system and an operating method. The system comprises a main compressor, a re-compressor, a precooler, a low-temperature heat regenerator, a medium-temperature heat regenerator, a high-temperature heat regenerator, a boiler, a high pressure turbine, a medium pressure turbine and a low pressure turbine. The inside of a boiler furnace bears furnace radiant heat loads together through arrangement of an overheating air cooling wall and a medium pressure reheater, and supercritical carbon dioxide overheating is prevented. According to the supercritical carbon dioxide cycle flue gas waste heat recovery coal-fired power generation system and the operating method, after parts of medium-temperature supercritical carbon dioxide working media are distributed from an outlet of the medium-temperature heat regenerator to enter a boiler, a vertical shaft flue high temperature flue gasheat exchanger absorbs high temperature flue gas heat; parts of low-temperature supercritical carbon dioxide working media are distributed from an outlet of the low-temperature heat regenerator to enter a boiler tail for distribution, and a flue medium-temperature flue gas heat exchanger absorbs medium-temperature flue gas heat; and parts of low-temperature supercritical carbon dioxide working media are distributed from an outlet of the main compressor to enter the boiler tail, a flue low-temperature flue gas heat exchanger absorbs low-temperature flue gas heat, and therefore the boiler exhaust gas temperature is lowered and boiler efficiency is improved.

Description

technical field [0001] The invention relates to the technical field of coal-fired power generation, in particular to a coal-fired power generation system and an operation method for recovering waste heat from supercritical carbon dioxide circulating flue gas. Background technique [0002] The world's energy demand continues to grow with the rapid development of the economy, and my country has ranked first in the global energy growth list for 17 consecutive years. Due to the serious imbalance of my country's fossil energy structure, coal has always been the main body of my country's primary energy consumption. Thermal power units are the largest consumers of coal in my country, and their annual coal consumption accounts for about half of the country's total coal consumption. Therefore, coal-based thermal power generation is still the main power generation method in my country. [0003] In recent years, my country has made great progress in the thermal power industry by adop...

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Problems solved by technology

However, due to the high radiation heat load of the boiler furnace, the heat absorption load of superheated carbon dioxide in the boiler is relatively low, and the arrangement of only a single superheated gas-cooled wall in the furnace will lead to overheating of superheated carbon dioxide, resulting in overheating of the metal wall temperature of the pipeline. Affect the safe operation of the boiler, so it is necessary to arrange the radiation heating surface in the boiler furnace reasonably; Unable to make full use of the flue gas heat at the tail of the boiler, resulting in excessively high boiler exhaust gas temperature and reduced boiler efficiency. Therefore, the configuration of the supercritical carbon dioxide power cycle system needs to be further optimized. It is urgent to improve the cycle by rationally arranging heaters and recovering waste heat from the flue gas. efficiency

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