Steam extraction back pressure type feed pump turbine back pressure adjusting system and method

Abstract

The invention relates to a steam extraction back pressure type feed pump turbine back pressure adjusting system and method. The system comprises a feed pump small turbine, a driving steam pipeline, aregenerative steam extraction pipeline, a regenerative steam extraction pipeline adjusting valve, a converging header, a steam extraction and supplementing pipeline adjusting valve, a discharging pipeline adjusting valve and a back pressure controller. The driving steam pipeline is connected with a small steam turbine; middle extraction steam of the small steam turbine enters a regenerative heaterthrough the regenerative steam extraction pipeline; exhaust gas of the small steam turbine enters the converging header; the exhaust gas of the small steam turbine enters the regenerative heater through the regenerative steam extraction pipeline adjusting valve; extracted steam from a main steam turbine enters the converging header through a regulating valve; the converging header is connected with a condenser through the regulating valve; and the extracted steam from the main steam turbine is connected with the regenerative steam extraction pipeline adjusting valve through the regulating valve and enters the regenerative heater. According to the system and method, start-stop of the small steam turbine and back pressure stable control of normal operation can be ensured, and effective steam extraction and backheating of the feed water heater are carried out while the small steam turbine normally drives the feed water pump.

Description

technical field [0001] The invention belongs to the technical field of thermal power generation, and in particular relates to a back pressure regulating system and method for a steam extraction back pressure type feed water pump steam turbine. Background technique [0002] With the development of high-parameter and large-capacity generating units with one million primary reheating and two-time reheating, ultra-supercritical units with high parameters of 35MPa inlet steam parameters are becoming research objects, which can further improve the cycle thermal efficiency of the unit and further promote Energy conservation. [0003] In order to reduce the superheat degree of extraction steam recovery under high parameter conditions, an extraction steam back pressure feedwater pump turbine unit system is proposed. That is, the feedwater pump is driven by setting a steam extraction back pressure small steam turbine, that is, at the same time, the steam extraction in the middle of t...

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Problems solved by technology

[0005] Due to the steam intake adjustment of the small steam turbine with back-pressure extraction and the power balance of the shaft system, it is not enough to completely solve the problem of safe operation control and economic control under variable load conditions

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