Direct-current furnace starting system matched with middle-pressure flash tank and used for comprehensively recycling working medium and heat

Abstract

The invention provides a direct-current furnace starting system matched with a middle-pressure flash tank and used for comprehensively recycling a working medium and heat, relating to a direct-current furnace starting system which is used by a supercritical direct-current furnace of a power station and can comprehensively recycle the working medium and the heat without starting a boiler water circulating pump. According to the direct-current furnace starting system provided by the invention, a middle-pressure expansion separator is used as a core. A deoxidizing system, a water supply system, a by-pass system, a condenser system, a starting system and a reheater system are called together in a starting process of the supercritical direct-current furnace of the power station, so that the starting process of the direct-current furnace is safely and economically completed under coordinative control of a DCS (Distributed Control System) of a unit, wherein the deoxidizing system, the water supply system, the by-pass system and the condenser system are arranged at a turbine side, and the starting system and the reheater device are arranged at a boiler side. The working medium and the heat can be comprehensively recycled in various working conditions in the starting process, so that not only can the working medium and the heat be comprehensively recycled by starting the direct-current furnace starting system of the boiler water circulating pump, but also the capital investment and the operation and maintenance cost can be greatly saved.

Description

(1) Technical field: [0001] The invention relates to a direct current furnace start-up system which can comprehensively recover working medium heat with an intermediate companding vessel, and relates to a direct current furnace start-up system which can fully recover working medium and heat by a non-starting furnace water circulation pump used in a supercritical direct current furnace of a power station. (two) background technology: [0002] The start-up system of the supercritical once-through boiler of the power station in the prior art is an important part of the supercritical once-through boiler of the power station. The purpose of setting up the start-up system is to establish and maintain the water cooling through the start-up system during the start-up, low-load operation and shutdown of the once-through boiler. The minimum mass flow rate in the wall is used to protect the safety of the water wall; at the same time, it meets the requirements of safe and economical star...

AI Technical Summary

Problems solved by technology

[0008] When starting the boiler water circulation pump to work normally, it is generally believed that the working fluid and heat can be fully recovered except for a few minutes during the expansion period of the water-cooled wall of the DC boiler. Corresponding pipes and valves are protected from excessive thermal shock, and about 20% of the start-up flow has been sent to the atmospheric expansion vessel since the DC furnace was ignited, and this part of the working medium and heat are basically lost; When the pump fails, it can still start the DC furnace safely, but it has degenerated into a C type DC furnace starting system

[0009] Type B once-through furnace start-up system is generally considered to be able to fully recover working fluid and heat except for a few minutes during the expansion period of the once-through furnace when the boiler water circulation pump is started to work normally. The pipeline is protected from excessive thermal shock. From the ignition of the once-through furnace, about 20% of the start-up flow has been sent to the condenser. This part of the working fluid is recovered and the heat is lost; it can still be used when the water circulation pump of the start-up furnace fails. Safely start the DC furnace, but it has degenerated into a D-type DC furnace starting system

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