Dual-pressure back-pressure turbine heat supply system

Abstract

The invention discloses a dual-pressure back-pressure turbine heat supply system. The dual-pressure back-pressure turbine heat supply system comprises a boiler, a dual-pressure back-pressure turbine,a shaft sealing heater, a drainage pump, a low-pressure heater, a deaerator, an electric water feeding pump, a first high-pressure heater and a second high-pressure heater; the dual-pressure back-pressure turbine comprises a high-pressure back-pressure turbine portion and a low-pressure back-pressure turbine portion which are connected in series, high-pressure exhausted steam is used for being conveyed to the deaerator from a pipeline after external heat supply, and low-pressure exhausted steam is connected to the low-pressure heater and used for heating demineralized water conveyed by the shaft sealing heater; condensation water of the low-pressure heater flows to the shaft sealing heater, and condensation water of the shaft sealing heater is pumped to the deaerator through the drainage pump; and shaft sealing leaked gas of the dual-pressure back-pressure turbine is connected to the shaft sealing heater through a pipeline and used for heating demineralized water for water replenishing, and the demineralized water heated by the low-pressure heater is connected to the deaerator. According to the system, no cold source loss is generated, part of the steam which is originally used forheating the demineralized water continues to doing work in the low-pressure back-pressure turbine portion, gradient utilization of energy is fully achieved, and the generating capacity of the back-pressure turbine is increased.

Description

technical field [0001] The invention relates to a heat supply system for a steam turbine, in particular to a heat supply system for a double-pressure backpressure steam turbine. Background technique [0002] The heat supply system of the back pressure machine in a conventional thermal power plant mainly includes a back pressure steam turbine and a heat recovery system. The heat supply of the back pressure machine in thermal power plants is directly supplied by the back pressure machine, and its heat recovery system generally consists of a shaft seal heater, a deaerator and a high pressure heater. At present, the parameters of the back pressure machine and its heat supply are generally that the main steam is high temperature and high pressure and the heating steam is about 0.49~1.57MPa. Or another steam turbine extraction port is provided. [0003] Generally, the ambient water at 20°C is heated to about 100°C, and the required steam parameters are about 0.11MPa. The therma...

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Problems solved by technology

[0006] Aiming at the deficiencies of the above-mentioned prior art, the present invention provides a dual-pressure back-pressure steam turbine heating system, which solves the energy loss caused by the high back pressure of the conventional bac

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