Supercritical carbon dioxide coal-fired power generation system with integrated waste heat recovery and its operation method

Abstract

The invention discloses a supercritical carbon dioxide coal-fired power generation system with an integrated waste heat recovery function and an operation method thereof. The system comprises a main compressor, a secondary compressor, a pre-cooler, 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, a low-pressure turbine and a primary air air preheater, wherein a boiler furnace is internally provided with a superheated gas cooling wall and the medium-pressure reheater, thetwo radiant heating surfaces jointly bear the radiant heat load of the boiler furnace, so that the overtemperature of the superheated supercritical carbon dioxide is prevented. According to the system and the operation method, a part of a low-temperature supercritical carbon dioxide working medium from an outlet of the low-temperature heat regenerator is guided into a tail flow division smoke channel of the boiler, a medium-temperature smoke gas heat exchanger absorbs heat of medium-temperature smoke gas, a part of the low-temperature supercritical carbon dioxide working medium is guided intoa tail smoke channel of the boiler from an outlet of the main compressor, and a low-temperature smoke gas heat exchanger absorbs heat of low-temperature smoke gas, so that the smoke discharging temperature of the boiler is reduced, the gradient utilization of energy is realized, and the efficiency of the boiler is improved.

Description

technical field [0001] The invention relates to the technical field of coal-fired power generation, in particular to a supercritical carbon dioxide coal-fired power generation system integrated with waste heat recovery and an operating method. Background technique [0002] Energy is the foundation of human survival and economic development, and the world's energy demand continues to grow with the rapid development of the economy. 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] Coal combustion emits a large amoun...

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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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