CN-121993832-A - Steam turbine exhaust cascade utilization heat supply system and method based on electric compressor

CN121993832ACN 121993832 ACN121993832 ACN 121993832ACN-121993832-A

Abstract

The invention discloses a steam turbine exhaust cascade utilization heat supply system and method based on an electric compressor, wherein the system comprises a steam source extraction unit, an electric steam compressor unit, a heat exchanger, a regulating valve, a parameter measurement unit and an integrated control unit; the heat exchanger is provided with a heat absorption side and a heat release side, an inlet of the heat absorption side is connected with an outlet of the electric steam compressor unit, the outlet of the heat absorption side is used for outputting heat supply steam, the regulating valve is arranged on a pipeline between a reheat section pipeline and an inlet of the heat release side of the heat exchanger and is used for controlling reheat steam flow entering the heat release side, the integrated control unit is used for regulating the working rotating speed of the compressor unit and the opening of the regulating valve in a closed loop mode according to the deviation of a received pressure signal and a preset target pressure and the deviation of a temperature signal and a preset target temperature, and therefore stability of the heat supply steam pressure and the temperature is achieved.

Inventors

LIU SHUAI
ZHAO CAI
YAN CHUANWU
ZHENG LEI
ZHANG XUEZHI
ZHANG XIAOPING
WANG BO
ZHANG ZUZHE
Zuo Chuangju
Sun Yuannan

Assignees

华电电力科学研究院有限公司

Dates

Publication Date: 20260508
Application Date: 20260319

Claims (10)

1. The steam turbine exhaust cascade utilization heat supply system based on the electric compressor is characterized by comprising a steam source extraction unit, an electric steam compressor unit, a heat exchanger, a regulating valve, a parameter measurement unit and an integrated control unit; the inlet of the steam source extraction unit is connected to a high-pressure cylinder steam exhaust pipeline of the steam turbine for extracting steam, The inlet of the electric vapor compressor unit is connected with the outlet of the vapor source leading unit and is used for compressing the extracted vapor to obtain compressed vapor; The heat exchanger is provided with a heat absorption side and a heat release side, wherein an inlet of the heat absorption side is connected with an outlet of the electric vapor compressor unit and is used for receiving compressed vapor, an outlet of the heat absorption side is used for outputting heat supply vapor, an inlet of the heat release side is used for receiving reheat vapor after passing through the regulating valve, and an outlet of the heat release side is connected with a high-pressure cylinder steam exhaust pipeline; the regulating valve is arranged on a pipeline between the reheat heat section pipeline and the heat release side inlet of the heat exchanger and is used for controlling reheat steam flow entering the heat release side; The parameter measuring unit is arranged on the heating steam output pipeline and is used for detecting the pressure and the temperature of the heating steam in real time and outputting a pressure signal and a temperature signal; the integrated control unit is respectively connected with the parameter measurement unit, the regulating valve and the electric vapor compressor unit and is used for adjusting the working rotation speed of the compressor unit in a closed loop according to the deviation between the received pressure signal and the preset target pressure, and simultaneously, the opening of the regulating valve is adjusted in a closed loop according to the deviation between the received temperature signal and the preset target temperature, the stability of the temperature of the heating vapor is realized by controlling the flow of the reheat vapor entering the heat release side, and finally, the decoupling control and the stable output of the pressure and the temperature of the heating vapor are realized.
2. The electric compressor-based turbine exhaust cascade utilization heating system of claim 1, wherein the steam source extraction unit comprises an isolation valve and a steam filtering device connected in sequence along a steam flow direction.
3. The electric compressor-based turbine exhaust cascade utilization heating system of claim 2, wherein the electric vapor compressor unit includes a variable frequency motor, a vapor compressor driven by the variable frequency motor, and a relief valve disposed at an outlet of the vapor compressor.
4. A cascade utilization heating system for steam turbine exhaust based on an electric compressor as claimed in claim 3, wherein the heat exchanger is a shell-and-tube heat exchanger, and the heat absorption side and the heat release side of the heat exchanger exchange heat in a partition wall type through a tube bundle.
5. The electric compressor-based turbine exhaust cascade utilization heating system of claim 4, wherein the exothermic side outlet is further provided with a check valve for avoiding reverse flow of steam.
6. The electric compressor-based turbine exhaust cascade utilization heating system of claim 5, further comprising a bypass unit disposed between the main steam line and the heating steam output line for emergency heating in the event of a failure of the electric compressor unit or the heat exchanger.
7. The heat supply system for cascade utilization of exhaust steam of a steam turbine based on an electric compressor as claimed in claim 6, wherein the bypass unit comprises a bypass valve and a bypass temperature and pressure reducing valve, one end of the bypass valve is connected to the main steam pipeline, the other end of the bypass valve is connected to the inlet of the bypass temperature and pressure reducing valve, and the outlet of the bypass temperature and pressure reducing valve is connected to the heat supply steam output pipeline.
8. A turbine exhaust cascade utilization heat supply method based on an electric compressor, adopting the turbine exhaust cascade utilization heat supply system based on an electric compressor as claimed in any one of claims 1 to 6, comprising: Extracting steam from a steam turbine high-pressure cylinder steam exhaust pipeline based on a steam source extraction unit; compressing the extracted steam by using an electric steam compressor unit to obtain compressed steam; introducing the compressed steam into a heat absorption side of a heat exchanger, extracting reheat steam from a reheat heat section pipeline of a steam turbine, regulating the reheat steam by a regulating valve, introducing the reheat steam into a heat release side of the heat exchanger, and heating the steam on the heat absorption side to obtain heating steam; Detecting the pressure and the temperature of the heating steam in real time by utilizing a parameter measuring unit, and outputting a pressure signal and a temperature signal; The integrated control unit is used for adjusting the opening degree of the regulating valve in a closed loop mode according to the deviation between the received temperature signal and the preset target temperature, and the stability of the temperature of the heating steam is realized by controlling the flow of the reheat steam entering the heat release side, and finally the decoupling control and the stable output of the pressure and the temperature of the heating steam are realized.
9. The electric compressor-based turbine exhaust cascade utilization heating method of claim 8, further comprising a fail-over step of: When the electric vapor compressor unit or the heat exchanger is detected to be in fault, the bypass valve is opened, and the operation of the compressor unit and the heat exchanger is stopped, so that the vapor is automatically switched to the bypass unit to supply heat.
10. A thermal power plant employing the electric compressor-based turbine exhaust cascade utilization heating system of any one of claims 1 to 8.

Description

Steam turbine exhaust cascade utilization heat supply system and method based on electric compressor Technical Field The invention belongs to the technical field of thermal power generation and comprehensive energy utilization, and particularly relates to a steam turbine exhaust cascade utilization heat supply system and method based on an electric compressor. Background In a cogeneration system of a large thermal power generating unit, a high-pressure cylinder of a steam turbine discharges steam, namely cold rebeam generally has lower pressure and temperature parameters, and the steam generally returns to a boiler to be reheated and then enters a middle-low pressure cylinder to continuously do work. With the increasing demand of industrial users for medium-pressure medium-temperature steam, how to effectively utilize this part of cold re-steam becomes a key problem in heat supply reformation. The parameters of cold re-steam are typically maintained at pressures in the range of 1.8-3.0 mpa and temperatures in the range of 300-350 degrees celsius, while many industrial users often require higher steam parameters, and direct use of cold re-steam cannot meet user requirements. The traditional solution thinking is to extract the steam with higher parameters from the main steam pipeline, and supply the steam with the parameters reduced by the temperature and pressure reducing device to users. Although the mode can ensure that the steam supply parameters meet the requirements, the main steam belongs to high-quality heat energy, and the use of the main steam in temperature and pressure reduction means that a large amount of working capacity is wasted, and the main steam is unreasonable from the aspect of energy cascade utilization. Another way is to simply boost the pressure of the cold re-steam, but the working characteristics of the compressor determine the pressure rise and the temperature of the steam changes, so that the simple pressure control cannot ensure the stability of the temperature parameter, and the temperature is just a key process parameter in the production process of many industrial users. In the actual operation process, the steam load of a heat user is not constant, and when the load fluctuates, the steam supply pressure and the steam supply temperature deviate. Under the traditional control mode, the pressure and the temperature are often independently regulated, and the pressure and the temperature are not effectively coordinated, so that the system response speed is low, the recovery time is long, and the stability requirement of a user on the steam supply quality is difficult to meet. Meanwhile, the reliability of the heating system is a non-negligible problem, and when the pressurizing equipment or the heat exchange equipment fails and needs to be shut down, how to ensure uninterrupted steam supply for users is an important factor to be considered when the system is designed, so that the production loss of users due to steam supply interruption is avoided. Based on the above-mentioned current situation, a heating solution is needed that can realize the coordinated control of the exhaust pressure and temperature of the high-pressure cylinder of the steam turbine, has a rapid load response capability, and can still ensure the continuity of steam supply under the fault condition at the same time, so as to realize the efficient cascade utilization of energy. Disclosure of Invention The invention aims to provide a turbine exhaust cascade utilization heat supply system and method based on an electric compressor, which can efficiently promote exhaust of a high-pressure cylinder in a turbine to high-parameter industrial steam meeting user requirements, fundamentally avoid direct throttling waste of high-quality main steam and realize cascade efficient utilization of energy with lower transformation cost and engineering implementation difficulty. In order to achieve the above purpose, the invention adopts the following technical scheme: The invention provides a steam turbine exhaust cascade utilization heat supply system based on an electric compressor, which comprises a steam source extraction unit, an electric steam compressor unit, a heat exchanger, a regulating valve, a parameter measurement unit and an integrated control unit, wherein the steam source extraction unit is connected with the electric steam compressor unit; the inlet of the steam source extraction unit is connected to a high-pressure cylinder steam exhaust pipeline of the steam turbine for extracting steam, The inlet of the electric vapor compressor unit is connected with the outlet of the vapor source leading unit and is used for compressing the extracted vapor to obtain compressed vapor; The heat exchanger is provided with a heat absorption side and a heat release side, wherein an inlet of the heat absorption side is connected with an outlet of the electric vapor compressor unit and is used for receiving compressed vapor, an ou