CN-121993273-A - Efficient heat recovery system of supercritical secondary reheating unit based on centripetal turbine

CN121993273ACN 121993273 ACN121993273 ACN 121993273ACN-121993273-A

Abstract

The invention discloses a supercritical secondary reheating unit efficient heat recovery system based on a centripetal turbine, and relates to the technical field of thermal power generation. The invention relates to a centripetal turbine back-pressure generator set, which comprises a high-pressure cylinder second-level steam extraction port and a medium-pressure cylinder fourth-level steam extraction port of a secondary reheating steam turbine, a same-level high-pressure heater, a generator and an energy storage unit, wherein a steam side inlet of the same-level high-pressure heater is connected with a steam outlet of the centripetal turbine back-pressure generator set and is used for receiving steam discharged by the centripetal turbine back-pressure generator set to heat water supply, the generator is coaxially connected with the centripetal turbine back-pressure generator set and is used for converting mechanical energy output by a turbine into electric energy, and the energy storage unit is connected with an electric power output end of the generator. The invention uses the energy of high-grade extraction steam in a cascade way of doing work firstly and then exchanging heat so as to replace the traditional direct heat exchanging mode, thereby recovering part of high-grade energy for generating electricity while ensuring the heating effect of the water supply.

Inventors

WANG WENYANG
SHAO FENG
CHEN YUE
SHAO FEI
WANG YU

Assignees

中煤(南京)电力科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260119

Claims (10)

1. The utility model provides a supercritical twice reheat unit high-efficient regenerative system based on centripetal turbine which characterized in that includes: the steam inlet of the centripetal turbine back-pressure generator set is connected with a high-pressure cylinder second-stage steam extraction port and a medium-pressure cylinder fourth-stage steam extraction port of the secondary reheat steam turbine through pipelines; The steam side inlet of the same-level high-pressure heater is connected with the steam outlet of the centripetal turbine back-pressure generator set and is used for receiving steam discharged by the centripetal turbine back-pressure generator set to heat water supply; the generator is coaxially connected with the centripetal turbine back pressure generator set and is used for converting mechanical energy output by the turbine into electric energy; And the energy storage unit is connected with the power output end of the generator and used for storing electric energy.
2. The supercritical secondary reheating unit efficient heat recovery system based on a centripetal turbine according to claim 1, further comprising a bypass pipeline (9) and a bypass valve (10) arranged on the bypass pipeline, wherein one end of the bypass pipeline (9) is connected to the upstream of a steam inlet of the centripetal turbine back pressure generator set, and the other end of the bypass pipeline is connected to the downstream of a steam outlet of the centripetal turbine back pressure generator set and is connected to a same-level high-pressure heater.
3. The efficient heat recovery system of the supercritical double reheating unit based on the centripetal turbine according to claim 2, wherein the number of the centripetal turbine back pressure generator sets is at least two groups of high-speed centripetal turbines, namely a second-stage turbine and a fourth-stage turbine, the second-stage turbine is connected with a high-pressure cylinder second-stage steam extraction port of the double reheating turbine, and the fourth-stage turbine is connected with a medium-pressure cylinder fourth-stage steam extraction port.
4. A supercritical secondary reheating unit efficient heat recovery system based on a centripetal turbine according to claim 3, wherein the same-level high-pressure heater comprises a second-level high-pressure heater (6) and a fourth-level high-pressure heater (7), wherein the second-level high-pressure heater (6) is connected to a steam outlet of the second-level turbine, and the fourth-level high-pressure heater (7) is connected to a steam outlet of the fourth-level turbine.
5. The supercritical double reheating unit efficient heat recovery system based on the centripetal turbine according to claim 4, wherein valves are arranged at steam inlet positions and steam outlet positions of the two-stage turbine and the four-stage turbine for controlling steam inlet and steam outlet.
6. The supercritical double reheating unit efficient heat recovery system based on the centripetal turbine according to claim 5, wherein turbine speed regulation modules are arranged at steam inlet positions of the two-stage turbine and the four-stage turbine, and the turbine speed regulation modules are arranged as hydraulic regulating valves.
7. The supercritical double-reheat unit efficient heat recovery system based on the centripetal turbine, as set forth in claim 6, wherein the generator is a permanent magnet synchronous generator, and the permanent magnet synchronous generator is coaxially connected with the centripetal turbine back pressure generator set through a gear box.
8. The supercritical double reheating unit efficient heat recovery system based on the centripetal turbine according to claim 2, further comprising a control unit, wherein the control unit is a DCS controller, the bypass valve (10) is a pneumatic or electric regulating valve, and the bypass valve (10), the steam inlet valve and the steam outlet valve of the secondary turbine and the steam inlet valve and the steam outlet valve of the quaternary turbine are all in communication connection with the control unit.
9. The supercritical double-reheat unit efficient regenerative system based on the centripetal turbine according to claim 7, wherein the energy storage unit is further connected to an electric heating boiler for realizing thermal decoupling.
10. The supercritical double-reheat unit efficient heat recovery system based on a centripetal turbine as set forth in claim 9, wherein the exhaust parameters of said centripetal turbine back-pressure generator set are designed to meet the requirements of said high-pressure heater of the same level for heating steam pressure and temperature.

Description

Efficient heat recovery system of supercritical secondary reheating unit based on centripetal turbine Technical Field The invention relates to the technical field of thermal power generation, in particular to a supercritical secondary reheating unit efficient heat recovery system based on a centripetal turbine. Background Along with the continuous improvement of the energy utilization efficiency requirement, the ultra-supercritical secondary reheating technology has become a main flow technical route for realizing higher heat efficiency of a modern large-scale coal-fired generator set. In such units, an external steam cooler (external steam cooler) is commonly used in the regenerator system in order to further improve the cycle efficiency. The typical working mode is that the water supply in the external steam cooler is preheated before the steam enters the conventional high-pressure heater by utilizing the higher superheat degree of the high-grade steam extraction (usually the high-pressure cylinder secondary steam extraction and the medium-pressure cylinder quaternary steam extraction) from the steam turbine. The process can improve the final boiler water supply temperature, so that the average heat absorption temperature of the whole Rankine cycle is improved, and the purpose of reducing the power generation coal consumption of the unit is achieved. However, the existing scheme of the regenerative system adopting the external evaporator gradually exposes the following technical limitations in actual operation: First, there is a disadvantage in terms of the flexibility of the operation of the unit. With the increasing requirements of the power grid on peak shaving and primary frequency modulation performance, the unit needs to have a faster load change rate. The conventional secondary reheating unit mainly depends on adjusting the opening degree of a main steam valve of a steam turbine to respond to load change, and obvious throttling loss can be generated in the process. Without auxiliary regulation means, the severe requirements of the new generation unit on the rapid variable load are difficult to meet by the method, and the power grid assessment can be faced due to insufficient response. Second, there are thermodynamic drawbacks in nature of energy utilization. The traditional external steam cooler is essentially a heat exchange device, and the pressure potential energy and overheat heat contained in the high-grade extraction steam are directly transferred to the water supply through a larger heat transfer temperature difference in the heat exchange process. This "direct heat exchange" mode fails to follow the high efficiency energy utilization principle of "per-mass energy utilization, cascade utilization". The steam is usually subjected to throttling or temperature and pressure reduction before entering the evaporator, and valuable working capacity is wasted, so that the system has inherent lifting space in terms of energy grade utilization (Yong efficiency). Therefore, the invention provides a supercritical secondary reheating unit efficient heat regeneration system based on a centripetal turbine. Disclosure of Invention The invention aims to provide a supercritical secondary reheating unit efficient heat recovery system based on a centripetal turbine, which can perform cascade utilization of 'first acting and then heat exchange' on high-grade extracted energy so as to replace the traditional 'direct heat exchange' mode, thereby ensuring the heating effect of water supply and recovering part of high-grade energy for power generation at the same time and further reducing the whole energy consumption of the unit. In order to achieve the purpose, the invention provides the following technical scheme that the supercritical secondary reheating unit efficient heat recovery system based on the centripetal turbine comprises the following components: the steam inlet of the centripetal turbine back-pressure generator set is connected with a high-pressure cylinder second-stage steam extraction port and a medium-pressure cylinder fourth-stage steam extraction port of the secondary reheat steam turbine through pipelines; The steam side inlet of the same-level high-pressure heater is connected with the steam outlet of the centripetal turbine back-pressure generator set and is used for receiving steam discharged by the centripetal turbine back-pressure generator set to heat water supply; the generator is coaxially connected with the centripetal turbine back pressure generator set and is used for converting mechanical energy output by the turbine into electric energy; And the energy storage unit is connected with the power output end of the generator and used for storing electric energy. Further, the device also comprises a bypass pipeline and a bypass valve arranged on the bypass pipeline, wherein one end of the bypass pipeline is connected to the upstream of the steam inlet of the centripetal turbine back pressu