Quick start method and system of combined cycle unit

Abstract

The invention relates to a quick start method and system of a combined cycle unit, which mainly detect and control the PH value of the condensed water by controlling the dissolved oxygen in the water and steam of a thermodynamic system and controlling the dissolved oxygen corrosion according to the relationship among temperature, pressure and content of dissolved oxygen of water and steam, by setting the content of dissolved oxygen in the condensed water to be less than or equal to 50microgram / L and by setting the content of dissolved oxygen in the water feed to be less than or equal to 15microgram / L, and adopts the combined deoxygenization manners of condenser vacuum deoxygenization and chemical dosing deoxygenization, and optimized operation mode and maintenance mode to ensure that the oxygen content in the condensed water in the combined cycle unit reaches the standard so as to avoid oxide etch of the metal due to that the oxygen content in the condensed water of the unit is excessive. The quick start system used for the combined cycle unit comprises a condenser; the water outlet of the condenser is connected with the input end of a condensed water flow meter through a condensed water pump and a shaft-sealing cooler; one loop of the outlet end of the condensed water flow meter is communicated with a boiler of the combined cycle unit through a condensed water cut-off valve, and the other loop is connected with a water return port of the condenser through a recycle cut-off valve and a recycle control valve; and a steam outlet of the condenser is connected with a vacuum pump through an air valve. The quick start method and system have the advantages that the overall structure of the thermodynamic system is simplified and the reliability and the economical efficiency of the system are improved.

Description

technical field [0001] The invention relates to a quick start method and a quick start system of a combined cycle unit, which are used to improve the response characteristics and economical efficiency of the unit. The invention belongs to the technical field of design and transformation mainly applied to the thermal system engineering of 9F level and above gas-steam combined cycle generator sets. Background technique [0002] At present, in the combined cycle unit of the invention factory, due to the existence of condensate and dissolved oxygen in feed water, it is an important cause of corrosion of thermal equipment in power plants. Corrosion of thermal equipment will affect the performance of materials, and the oxides and scales produced by it will It will affect the safe operation of the unit. The dissolved oxygen content of condensate water and feed water needs to be controlled at a more appropriate level. The national standard (GB / T 12145-2008) requires that the dissol...

AI Technical Summary

Problems solved by technology

[0008] One of the purposes of the present invention is to provide a rapid start-up method for combined cycle units in order to overcome the defects of complex overall structure, high accident rate and seriously affecting the start-up and grid connection time of the special deaerator in the prior art

Images