The system and working method of the 350mw supercritical double pumping unit feed water pump steam turbine direct exhaust air cooling island

Abstract

The invention provides a direct exhaust air cooling island system of a water feed pump turbine of a 350MW supercritical double-extraction unit and a work method of the direct exhaust air cooling island system of the water feed pump turbine of the 350MW supercritical double-extraction unit. Steam extracted from a medium-pressure cylinder is conveyed into the water feed pump turbine. A branch of a steam exhaust opening of a high-pressure cylinder communicates with a low-pressure steam source pipeline of the water feed pump turbine through a high-pressure steam source pipeline of the water feed pump turbine. The high-pressure steam source pipeline of the water feed pump turbine is used as a standby steam supply pipeline to input steam into the water feed pump turbine. The low-pressure steam source pipeline of the water feed pump turbine is further provided with a check valve which prevents the steam from flowing backward to the medium-pressure cylinder when the high-pressure steam source pipeline of the water feed pump turbine conveys the steam into the water feed pump turbine. A steam exhaust opening of the water feed pump turbine communicates with an air cooling island through a steam exhaust pipeline of the water feed pump turbine. By the adoption of the cooling manner of a direct exhaust main machine of a water feed pump, the support equipment purchasing expense is greatly reduced, the cost is reduced, the occupied space of the equipment is reduced, reasonable ventilation space of the equipment is saved, support equipment maintenance is omitted, water is also saved, and the annual return rate of the unit is increased.

Description

technical field [0001] The invention relates to the field of direct discharge air-cooled island equipment of a steam-driven feedwater pump in a thermal power plant, in particular to a system and a working method for a 350MW supercritical double pumping unit feedwater pump steam turbine direct discharge air-cooled island. Background technique [0002] At present, the cooling method of the feedwater pump steam turbine of the direct cooling unit in my country mainly adopts a separate indirect air cooling system for cooling, and the separate cooling method is divided into a mechanical ventilation indirect air cooling system and a natural ventilation indirect air cooling system; there is also an immature cooling method at present. 350MW super The critical double pumping unit feedwater pump steam turbine direct exhaust air cooling island system, but compared with the separate cooling method of the feedwater pump steam turbine, it saves a lot of supporting equipment, greatly reduces ...

AI Technical Summary

Problems solved by technology

[0003] The main problems of the current 350MW supercritical double pumping unit feedwater pump steam turbine direct discharge air cooling island system are as follows: First, the back pressure of the condensing device is greatly affected by the steam temperature, wind speed, wind direction, etc., and the back pressure changes during the operation of the unit Large and frequent, the adjustment requirements for the feedwater pump turbine are high, and frequent adjustments are required during operation; secondly, because the exhaust steam of the feedwater pump steam turbine is directly sent to the large machine condensing device, when the back pressure increases, in order to maintain the flow of the feedwater pump, the feedwater pump There is a phenomenon of steam grabbing in the steam turbine and the main steam turbine, which will cause load fluctuations and make it difficult to adjust the unit as a whole. Especially in windy or gusty weather, the back pressure changes frequently and violently, which will easily cause frequent adjustments of the feedwater pump steam turbine and unstable output of the feedwater pump; Fourth, the once-through boiler is different from the previous drum boiler, once-through boiler It has no heat storage capacity, is sensitive to changes in steam temperature and pressure, and has high requirements for automatic control systems

Images