Coal-fired boiler flue gas and steam combined heat storage deep peak shaving system and operation method

Abstract

The invention discloses a coal-fired boiler flue gas and steam combined heat storage deep peak shaving system and an operation method. The system comprises a coal-fired power generation unit thermodynamic system and a heat storage system which is coupled with the coal-fired power generation unit thermodynamic system and comprises a cold and hot heat storage medium tank, a cold heat storage medium tank outlet adjusting valve, a cold heat storage medium pump, heat storage medium heaters, a water supply preheater and the like. The heat storage medium heaters are arranged in a boiler flue and on the side of a steam turbine, the flow of heat storage media entering the heat storage medium heaters is adjusted through the heat storage medium pump, meanwhile, heat of boiler smoke and heat of steam of the steam turbine are absorbed, a unit stably operates under the extremely low load, meanwhile, the boiler smoke exhaust temperature is reduced, and the economical efficiency of the unit is improved; and the flow of water supply and heat storage media entering a heat storage medium and water supply heat exchanger is adjusted through a high-pressure heater bypass adjusting valve set, a low-pressure heater bypass adjusting valve set and a heat storage medium and water supply heat exchanger inlet adjusting valve, so that the system meets the requirement for the rapid variable load rate of the unit. According to the coal-fired boiler flue gas and steam combined heat storage deep peak shaving system and the operation method, the working load range of the unit can be expanded, and flexibility and economical efficiency can be improved.

Description

technical field [0001] The invention relates to the technical field of coal-fired power generation, in particular to a coal-fired boiler flue gas and steam combined heat storage deep peak-shaving system and an operating method. Background technique [0002] With the rapid increase in the use of renewable energy such as solar energy and wind energy around the world, its volatility, intermittency, and unpredictability have brought great challenges to the stable and safe operation of the power grid. In order to maintain the stability and safety of the power grid and adapt to the growing use of renewable energy, improving the operational flexibility of coal-fired power generation units plays an important role in the transition process of the current power system. In this case, coal-fired units are required to expand their working load range while increasing the variable load rate, especially to reduce the minimum generating power, that is, the minimum load. The strong coupling ...

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Problems solved by technology

The strong coupling between the boiler and the steam turbine of the existing thermal system unit limits the minimum output of the coal-fired generating unit. At present, there is no reasonable solution to enable the thermal generating unit to meet the requirements of the power grid for the variable load and low-load operation performance of the unit. At the same time, The exhaust temperature of the boiler is often above 120°C, causing a large amount of energy loss, and the recovery and utilization of flue gas waste heat often requires the addition of more expensive heat exchange equipment, and investment costs must be considered. Therefore, the problems that need to be solved include:

3) The exhaust temperature of the boiler is high, causing a large amount of energy loss, and an effective and cheap way is needed to reduce the exhaust temperature and improve the economy of the unit

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