Supercritical carbon dioxide cycle power generation system

Abstract

The invention discloses a supercritical carbon dioxide cycle power generation system which can recover a supercritical carbon dioxide medium discharged emergently during quick shutdown. Comprising a turbine, a compressor and a gas supply system, the gas supply system is connected with a high-pressure tank, a first cooler, a surge tank, the compressor, a regenerator heating channel, a heater, the turbine, a regenerator cooling channel and the first cooler, and the turbine is provided with a turbine inlet emergency discharge outlet and a turbine inlet discharge regulating valve. The compressor is provided with a compressor outlet emergency discharge port and a compressor outlet discharge regulating valve, the turbine inlet discharge regulating valve is connected with a first pressure reducing valve, the compressor outlet discharge regulating valve is connected with a second pressure reducing valve, and the downstream ends of the first pressure reducing valve and the second pressure reducing valve are converged and then connected with a buffer tank and a second cooler; the second cooler is connected with a compressor inlet and a reciprocating piston compressor, and the reciprocating piston compressor is connected with a high-pressure tank.

Description

Technical Field

[0001] The invention relates to the technical field of a circulation power generation system using supercritical carbon dioxide as a medium, and in particular to a supercritical carbon dioxide circulation power generation system. Background Art

[0002] In the existing supercritical carbon dioxide cycle power generation system, when dealing with emergencies such as generator disconnection, the need to quickly reduce the power generation load, and equipment failure requiring rapid shutdown, the system operates by urgently draining the supercritical carbon dioxide medium in the circulation system pipeline to protect the unit from rapid shutdown or reduce the power generation load. This type of operation seriously wastes the system's circulating medium and is not economical.

[0003] The supercritical carbon dioxide circulation power generation system is now redesigned from the perspective of recycling economy, so that the system can recycle the supercritical carbon dioxide medium in emergency situations to avoid waste. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a supercritical carbon dioxide circulation power generation system which can recover the supercritical carbon dioxide medium discharged in an emergency during rapid shutdown.

[0005] The object of the present invention is achieved in that: A supercritical carbon dioxide cycle power generation system includes a turbine, a compressor, a system process medium circulation system, and a medium recovery system. The system process medium circulation system includes a gas supply system, which is used to replenish the carbon dioxide medium. The gas supply system is connected to the high-pressure tank, the first cooler, the pressure-stabilizing tank, and the compressor inlet in sequence through pipelines. The compressor outlet is connected to the regenerator heating channel, the heater, and the turbine inlet in sequence through pipelines. The turbine outlet is connected to the regenerator cooling channel and the first cooler in sequence through pipelines to form a medium circulation. The turbine inlet end is also provided with a turbine inlet emergency discharge port, and the compressor outlet end is also provided with a compressor outlet emergency discharge port; The medium recovery system includes a turbine inlet discharge regulating valve arranged at the turbine inlet emergency discharge port, and a compressor outlet discharge regulating valve arranged at the compressor outlet emergency discharge port. The turbine inlet discharge regulating valve is connected to the first pressure reducing valve through a pipeline, and the compressor outlet discharge regulating valve is connected to the second pressure reducing valve through a pipeline. The downstream ends of the first pressure reducing valve and the second pressure reducing valve are connected through a pipeline for mixed cooling, and then connected to a buffer tank and a second cooler in sequence through a pipeline. The outlet end of the second cooler is connected to the compressor inlet and the reciprocating piston compressor through pipelines, and the reciprocating piston compressor is connected to the high-pressure tank.

[0006] Preferably, the first cooler and the second cooler cool down the medium by circulating cooling water so that the medium temperature reaches the compressor inlet design temperature.

[0007] Preferably, the gas supply system supplies a sufficient amount of carbon dioxide medium and then cuts off the supply through a valve.

[0008] Preferably, a bypass regulating valve is connected between the inlet and outlet ends of the turbine. The bypass regulating valve is used during the startup process to allow the medium to circulate in the turbine to increase pressure and temperature. It is also used to divert the turbine intake volume in an emergency.

[0009] Preferably, an anti-surge regulating valve is connected between the inlet and outlet ends of the compressor, and the compressor surge is prevented by adjusting the anti-surge regulating valve.

[0010] Preferably, it also includes a dry gas sealing system. When the machine is started, the sealing gas of the dry gas sealing system is provided by the gas supply system. When the system medium circulation is established, the sealing gas of the dry gas sealing system is provided by the compressor outlet, and the sealing gas provided by the gas supply system is cut off at the same time.

[0011] Preferably, the buffer tank is equipped with a pressure transmitter and a temperature transmitter, which monitor the temperature and pressure of the medium. An emergency drain valve is installed on the top of the buffer tank to prevent the buffer tank from overpressure.

[0012] Due to the adoption of the above technical solution, the present invention can recover the supercritical carbon dioxide medium discharged in an emergency during rapid shutdown. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is the system process schematic diagram; Figure 2 Schematic diagram of the media recovery system.

[0014] Reference numerals In the attached drawings, 1-heater, 2-turbine inlet discharge regulating valve, 3-regenerator, 4-compressor outlet discharge regulating valve; 5-pressure stabilizing tank; 6-compressor anti-surge regulating valve; 7-cooler; 8-turbine inlet bypass regulating valve; 9-turbine compressor integrated machine; 10-high-pressure tank; 11-dry gas sealing system; 12-compressor pressure reducing valve; 13-turbine pressure reducing valve; 14-buffer tank; 15-cooler; 16-reciprocating piston compressor. DETAILED DESCRIPTION

[0015] See also Figure 1 , Figure 2, which is a supercritical carbon dioxide cycle power generation system. It includes a turbine, a compressor, a system process medium circulation system, and a medium recovery system. The system process medium circulation system includes a gas supply system, which is used to replenish carbon dioxide medium. The gas supply system is connected to the high-pressure tank, the first cooler, the pressure-stabilizing tank, and the compressor inlet in sequence through pipelines. The compressor outlet is connected to the regenerator heating channel, the heater, and the turbine inlet in sequence through pipelines. The turbine outlet is connected to the regenerator cooling channel and the first cooler in sequence through pipelines to form a medium cycle. The turbine inlet end is also provided with a turbine inlet emergency discharge port, and the compressor outlet end is also provided with a compressor outlet emergency discharge port.

[0016] The medium recovery system includes a turbine inlet discharge regulating valve arranged at the turbine inlet emergency discharge port, and a compressor outlet discharge regulating valve arranged at the compressor outlet emergency discharge port. The turbine inlet discharge regulating valve is connected to the first pressure reducing valve through a pipeline, and the compressor outlet discharge regulating valve is connected to the second pressure reducing valve through a pipeline. The downstream ends of the first pressure reducing valve and the second pressure reducing valve are connected through a pipeline for mixed cooling, and then connected to a buffer tank and a second cooler in sequence through a pipeline. The outlet end of the second cooler is connected to the compressor inlet and the reciprocating piston compressor through pipelines, and the reciprocating piston compressor is connected to the high-pressure tank.

[0017] The first cooler and the second cooler cool down the medium through circulating cooling water to make the medium temperature reach the compressor inlet design temperature. After the gas supply system supplies a sufficient amount of carbon dioxide medium, the supply is cut off through the valve. A bypass regulating valve is connected between the inlet and outlet of the turbine. The bypass regulating valve is used in the startup process to make the medium circulate in the turbine to increase the pressure and temperature. It is also used to divert the turbine intake volume in an emergency. An anti-surge regulating valve is connected between the inlet and outlet of the compressor. The anti-surge regulating valve is adjusted to prevent the compressor from surging.

[0018] It also includes a dry gas sealing system. When the machine is started, the sealing gas of the dry gas sealing system is provided by the gas supply system. When the system medium circulation is established, the sealing gas of the dry gas sealing system is provided by the compressor outlet, and the sealing gas provided by the gas supply system is cut off at the same time. The buffer tank is equipped with a pressure transmitter and a temperature transmitter to monitor the temperature and pressure of the medium. An emergency vent valve is installed on the top of the buffer tank to prevent the buffer tank from overpressure.

[0019] How the system works: 1. See Figure 1 , System process medium circulation system: 1) The external gas supply system supplies carbon dioxide medium, which enters the compressor inlet pipeline after passing through the high-pressure tank 10, and then enters the compressor inlet after passing through the first cooler 7 and the pressure-stabilizing tank 5 (used to stabilize the compressor inlet pressure).

[0020] 2) After the carbon dioxide is pressurized by the compressor, it enters the regenerator 3 (waste heat recovery) through the compressor outlet pipeline, and finally enters the heater 1 for heating.

[0021] 3) The heated carbon dioxide enters the turbine inlet through the outlet pipeline to perform work. The carbon dioxide that has performed work enters the regenerator 3 through the turbine outlet, and exchanges the usable heat with the carbon dioxide medium after the compressor is pressurized, thereby improving the cycle efficiency.

[0022] 4) The carbon dioxide after heat exchange enters the first cooler 7 through the pipeline (it is cooled by circulating cooling water to reach the compressor inlet design temperature), and finally enters the compressor inlet through the pressure stabilizing tank 5, forming a cycle.

[0023] 5) After the external system is replenished, the supply pipeline is cut off by the valve.

[0024] 6) There is a bypass regulating valve 8 between the turbine inlet pipeline and the outlet pipeline, which is used to increase the pressure and temperature of the medium during the startup process, and is also used to divert the turbine intake volume in an emergency.

[0025] 7) The anti-surge regulating valve 6 between the compressor inlet and outlet pipelines is used to prevent the compressor from surging.

[0026] 8) When the dry gas sealing system 11 is started, sealing gas is provided by the external supply system and the high-pressure tank 10. When the system circulation is established, the sealing gas is provided by the compressor outlet and the external supply system is cut off at the same time.

[0027] 2. See Figure 2 , media recovery system: 1) The discharge medium of the turbine inlet emergency discharge port is high-temperature and high-pressure supercritical carbon dioxide, and the discharge medium of the compressor outlet emergency discharge port is low-temperature supercritical carbon dioxide. The turbine inlet discharge regulating valve 2 and the compressor outlet discharge regulating valve 4 are the emergency discharge valves for the turbine inlet and the compressor outlet respectively. In an emergency, the system circulation flow is reduced by controlling the valve opening, thereby reducing the unit load or even shutting down. The high-temperature medium discharged from the turbine enters the buffer tank 14 after passing through the second pressure reducing valve 13, and the low-temperature medium discharged from the compressor outlet passes through the first pressure reducing valve 12 to mix and cool the turbine discharge medium, and finally enters the buffer tank 14.

[0028] 2) The buffer tank 14 is equipped with a pressure transmitter and a temperature transmitter to monitor the temperature and pressure of the medium. At the same time, an emergency drain valve is installed on the top of the tank to prevent overpressure.

[0029] The outlet pipeline of the buffer tube is connected to the second cooler 15. After being cooled by the cooler, the carbon dioxide is connected to the compressor inlet pipeline on one side and can continue to participate in the system circulation. The other side enters the reciprocating piston compressor 16 after being cooled, and enters the high-pressure tank 10 for storage after being pressurized, which is convenient for subsequent filling system use.

[0030] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A supercritical carbon dioxide cycle power generation system, comprising a turbine and a compressor, characterized in that: It also includes the system process medium circulation system and medium recovery system. The system process medium circulation system includes a gas supply system, which is used to replenish the carbon dioxide medium. The gas supply system is connected to the high-pressure tank, the first cooler, the pressure-stabilizing tank, and the compressor inlet in sequence through pipelines. The compressor outlet is connected to the regenerator heating channel, the heater, and the turbine inlet in sequence through pipelines. The turbine outlet is connected to the regenerator cooling channel and the first cooler in sequence through pipelines to form a medium circulation. The turbine inlet end is also provided with a turbine inlet emergency discharge port, and the compressor outlet end is also provided with a compressor outlet emergency discharge port; The medium recovery system includes a turbine inlet discharge regulating valve arranged at the turbine inlet emergency discharge port, and a compressor outlet discharge regulating valve arranged at the compressor outlet emergency discharge port. The turbine inlet discharge regulating valve is connected to the first pressure reducing valve through a pipeline, and the compressor outlet discharge regulating valve is connected to the second pressure reducing valve through a pipeline. The downstream ends of the first pressure reducing valve and the second pressure reducing valve are connected through a pipeline for mixed cooling, and then connected to a buffer tank and a second cooler in sequence through a pipeline. The outlet end of the second cooler is connected to the compressor inlet and the reciprocating piston compressor through pipelines, and the reciprocating piston compressor is connected to the high-pressure tank.

2. A supercritical carbon dioxide cycle power generation system according to claim 1, characterized in that: The first cooler and the second cooler cool down the medium by circulating cooling water to make the medium temperature reach the compressor inlet design temperature.

3. A supercritical carbon dioxide cycle power generation system according to claim 1, characterized in that: After the gas supply system is replenished with a sufficient amount of carbon dioxide medium, the supply is cut off through a valve.

4. A supercritical carbon dioxide cycle power generation system according to claim 1, characterized in that: A bypass regulating valve is connected between the inlet and outlet ends of the turbine. The bypass regulating valve is used during the startup process to allow the medium to circulate in the turbine to increase pressure and temperature. It is also used to divert the turbine intake volume in an emergency.

5. A supercritical carbon dioxide cycle power generation system according to claim 1, characterized in that: An anti-surge regulating valve is connected between the inlet and outlet ends of the compressor, and the compressor surge is prevented by adjusting the anti-surge regulating valve.

6. A supercritical carbon dioxide cycle power generation system according to claim 1, characterized in that: It also includes a dry gas sealing system. When the machine is started, the sealing gas of the dry gas sealing system is provided by the gas supply system. When the system medium circulation is established, the sealing gas of the dry gas sealing system is provided by the compressor outlet, and the sealing gas provided by the gas supply system is cut off at the same time.

7. A supercritical carbon dioxide cycle power generation system according to claim 1, characterized in that: The buffer tank is equipped with a pressure transmitter and a temperature transmitter to monitor the temperature and pressure of the medium. An emergency drain valve is installed on the top of the buffer tank to prevent the buffer tank from overpressure.

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