Inlet air temperature adjusting system for combined cycle unit of LNG power station, and method

Abstract

The invention discloses an inlet air temperature adjusting system for a combined cycle unit of an LNG power station, and a method. The method mainly comprises an LNG gasification cold energy recycling link and a unit flue gas waste heat recycling link. In the LNG gasification cold energy recycling link in the high-temperature season, cold energy in the LNG gasification process is recycled through a two-stage cold energy heat exchange system to prepare cooling water, the cooling water is used for cooling inlet air of the unit, and the inlet air temperature of the unit is reduced, so that unit output and heat efficiency are improved, and the peak regulation performance of the combined cycle unit is improved. In the unit flue gas waste heat recycling link in the low-temperature season link, flue gas waste heat in the power generation process of the combined cycle unit is recycled through the heat energy heat exchange system to prepare hot water, and the hot water is used for heating the inlet air of the unit, so that the situation that the air temperature entering the unit is below the dew point temperature so as to cause freezing of moisture contained in air to threaten the safety operation of the unit is prevented, and the net efficiency of the unit under full load can be improved.

Description

technical field [0001] The invention belongs to the technical field of energy system surplus energy utilization, and in particular relates to a system and method for regulating the intake air temperature of a combined cycle unit of an LNG power station. Background technique [0002] LNG generally refers to liquefied natural gas, the main component is methane, and a small amount of ethane and propane. It is a liquid alkane mixture formed by cooling and liquefying natural gas through a low-temperature process after drying and purification. It is usually stored at a low temperature of -162°C and 0.1MPa. in the storage tank. LNG can not only be used as fuel, but also carry a large amount of high-grade cold energy. The cold energy released during the gasification process is as high as 830kJ / kg (including latent heat of gasification and sensible heat raised to ambient temperature). LNG power plants need to gasify LNG to raise the temperature first, during which the cold energy of...

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Problems solved by technology

At the same time, the air intake of the unit is a process of reducing pressure and increasing speed, and there will be a temperature drop of about 5°C during this period. If the waste heat of the flue gas of the unit is reasonably used as a heat source to increase the intake temperature of the unit in low temperature seasons, it can effectively prevent Too low temperature will lead to the risk of "water blockage and ice blockage" in the unit; at present, the adjustment of the intake air temperature of the combined cycle unit is mainly realized by using the heat supply and extraction steam of the steam turbine or the low-pressure main steam as the heat source and preparing the cold source at the same time, but Extracting high-grade steam as a heat medium will have an adverse effect on unit output and thermal efficiency

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