A supercritical carbon dioxide turbine insulation device capable of automatic suspension and a control method thereof

Abstract

The present invention discloses an automatically suspended supercritical carbon dioxide turbine insulation device and control method, comprising a CO2 turbine body, an insulation layer attached to the outer wall of the CO2 turbine body, the insulation layer attached adopts a louver-type insulation material, the insulation material adopts a fixed support and a movable support double-layer support, and the insulation material is distributed with reserved holes of different sizes and shapes, and the reserved holes are used to install the signal measurement element of the CO2 body. The present invention can not only meet the requirements of strict insulation of the carbon dioxide turbine during the startup and temperature rise stage, but also meet the requirements of the insulation device that the outer cylinder wall temperature can be quickly cooled after the carbon dioxide turbine trips under high parameters, and can effectively solve the problems in the background technology.

Description

Technical Field

[0001] The invention belongs to the technical field of supercritical carbon dioxide turbine insulation, and in particular relates to an automatically suspended supercritical carbon dioxide turbine insulation device and a control method. Background Art

[0002] Due to the different physical properties of carbon dioxide and water vapor, supercritical carbon dioxide turbines exhibit very different characteristics from steam turbines using water vapor as the working fluid. Currently, supercritical carbon dioxide turbines of the MW level have fewer power stages, shorter rotors, and smaller cylinder volumes. When the carbon dioxide turbine is in the startup phase, the metal temperature of the inner wall of the cylinder rises faster as the CO2 working fluid does work, while the metal temperature of the outer wall of the cylinder heated by heat conduction rises more slowly, which results in a large temperature difference between the inner and outer cylinders of the carbon dioxide turbine during the startup and load increase phases, thereby limiting the load increase rate of the turbine. When the carbon dioxide turbine trips under high parameters, with the rapid discharge of the CO2 working fluid in the cylinder and the forced cooling of the dry gas sealing gas, the metal temperature of the inner wall of the cylinder drops faster, while the metal temperature of the outer wall of the cylinder can only be cooled naturally by thermal radiation, which also causes the temperature difference between the inner and outer cylinders of the carbon dioxide turbine to exceed the limit, and even causes arch back deformation of the cylinder and radial friction between the moving and static parts inside the cylinder, which is very risky.

[0003] At present, there are two forms of turbine insulation materials for this new type of CO2 working fluid. One is to lay the insulation material on the outer wall of the turbine to form a tight package to prevent high-temperature heat dissipation during the turbine heating stage; the other is to suspend the insulation material as a whole on the outer wall of the turbine to form an integral cavity in the middle, which is used to reduce the temperature of the outer wall of the turbine as soon as possible through air convection in the cavity after the turbine trips, thereby reducing the temperature difference between the inner and outer walls. However, these two forms cannot take into account the operation requirements of the turbine under all working conditions.

[0004] Therefore, it is necessary to design an insulation device that can not only meet the requirements of strict insulation during the startup and heating stage of the supercritical carbon dioxide turbine, but also meet the requirements of rapid cooling of the outer cylinder wall temperature after the carbon dioxide turbine trips under high parameters, so as to solve the existing problems. Summary of the invention

[0005] In order to overcome the above technical problems, the present invention provides an automatically suspended supercritical carbon dioxide turbine insulation device and control method, which can not only meet the requirements of strict insulation of the carbon dioxide turbine during the startup and heating stage, but also meet the requirements of rapid cooling of the outer cylinder wall temperature after the carbon dioxide turbine trips under high parameters, and can effectively solve the problems in the background technology.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A supercritical carbon dioxide turbine insulation device that can be automatically suspended and stacked includes a CO2 turbine body 1. The outer wall of the CO2 turbine body 1 is attached with an insulation layer 2. The insulation layer 2 uses insulation material 3 distributed in a louvered manner. The insulation material 3 is supported by a double-layer bracket of a fixed bracket 4 and a movable bracket 18. The insulation material 3 is distributed with reserved holes 9 of different sizes and shapes. The reserved holes 9 are used to install signal measurement elements of the CO2 body 1.

[0008] The CO2 turbine body 1 is provided with an air intake channel 6 and an exhaust channel 7. The air intake channel 6 is connected to the outlet of the cooling fan 10. An isolation valve 11 and an air intake control valve 5 are provided between the cooling fan 10 and the air intake channel 6. The exhaust channel 7 is connected to a muffler 13 through a pipeline, and a check valve baffle 12 is provided on the pipeline.

[0009] The fixed bracket 4 is a high-temperature resistant metal strip, which is attached to the outer wall along the radial direction of the turbine, arranged at intervals, and surrounds the outer wall of the turbine. The fixed bracket 4 and the insulation material 3 are fixed by a traction shaft 8. The movable bracket 18 is used to support the insulation material 3. The lower edge surface of the insulation material and the outer wall of the turbine can be supported by a maximum of 45°, forming layers of surrounding gas flow cavities between the insulation material 3 and the outer wall of the CO2 turbine body 1.

[0010] The movable bracket 18 is a high-temperature resistant metal strip, which is arranged at intervals along the turbine axis and connected to the rolling shaft 15 through a traction rope 16. The rolling shaft 15 is driven by an electric motor 14. The maximum movable distance of the movable bracket 18 is contact with the limit switch contact 17. At this time, the maximum angle between the movable bracket 18 and the insulation material 3 is 45°.

[0011] The air intake control valve 5 is a pneumatic valve.

[0012] A control method for an automatically foldable supercritical carbon dioxide turbine insulation device comprises the following steps:

[0013] The heat preservation device is controlled by a PLC controller, which includes three groups of input signals and three groups of output signals, namely, the trip signal (in1) of the CO2 turbine body 1, the temperature difference ΔT between the inner and outer wall cylinders of the CO2 turbine body 1 (in2) and the limit switch contact (in3); the operation / stop of the electric motor 14 (out1), the operation / stop of the cooling fan 14 (out2) and the opening / closing of the intake control valve 5 (out3);

[0014] The temperature difference ΔT(in2) between the inner and outer walls of the CO2 turbine body 1 is obtained by the difference between the metal temperature T2 of the inner wall of the turbine and the metal temperature T1 of the outer wall of the turbine, that is, ΔT = T2-T1;

[0015] During the startup phase of the CO2 turbine body 1, that is, when the turbine trip signal (in1) is not sent, no matter how large the temperature difference ΔT (in2) between the inner and outer walls of the turbine is, the electric motor 14 will not be triggered to run;

[0016] When the PLC controller simultaneously receives the turbine trip signal (in1) and the temperature difference between the inner and outer cylinder walls of the turbine ΔT>35°C (in2), the electric motor 14 is triggered to run; when the limit switch contact 17 on the movable bracket 18 is closed, the movable bracket 18 slides into place and the electric motor 14 stops;

[0017] When the limit switch contact 17 on the movable bracket 18 is closed, the cooling fan 10 starts automatically; after the cooling fan 10 starts automatically, the air intake control valve 5 opens in a chain manner. During the normal operation of the unit, the outlet isolation valve 11 of the cooling fan 10 remains in a normally open state.

[0018] Beneficial effects of the present invention:

[0019] 1) The present invention has a simple structure, is stable and reliable, and can fold the louver-type thermal insulation material up to a maximum angle of 45° through the dual support design of the fixed support and the movable support, effectively forming a cooling air chamber, which is convenient to adjust as a whole, simple to install, and easy to operate.

[0020] 2) By designing the switch limit contacts, on the one hand, the telescopic position of the movable bracket can be limited, and on the other hand, the start and stop of the electric motor can be controlled.

[0021] 3) The PLC controller can be used to realize the full automatic operation of the entire insulation device. Through the comprehensive judgment of the input signal of the PLC controller, the start-up of the electric motor, the operation of the cooling fan and the opening of the air intake control valve can be realized in sequence.

[0022] 4) The precise measurement of the inner and outer wall temperatures of the CO2 turbine and the temperature difference calculation are used as the criterion for the PLC controller input signal. The signal is triggered when the temperature difference is greater than 35°C and the signal is reset when the temperature difference is less than 5°C.

[0023] 5) The cooling fan is automatically started and stopped through the limit switch contacts, and the start and stop of the cooling fan interlocks the opening and closing of the air intake control valve. The logic and hierarchy between each device are clear, forming a closed-loop control under all working conditions.

[0024] 6) The present invention can not only meet the thermal insulation requirements of the supercritical CO2 turbine during the startup and temperature rise stage, but also meet the requirements of rapidly cooling the turbine outer wall cylinder temperature and reducing the temperature difference between the inner and outer wall cylinders after the unit is shut down due to an accident during the high load stage, thereby improving the overall operation safety of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0026] Figure 2 It is a schematic diagram of the operation flow of the present invention.

[0027] Figure 3 It is a schematic structural diagram of the heat preservation device of the present invention in a folded state.

[0028] Figure 4 It is a structural schematic diagram of the heat preservation device of the present invention when it is in a suspended state.

[0029] Figure 5 It is a schematic diagram of the double support and drive structure of the heat preservation device of the present invention.

[0030] Figure 6 It is an enlarged schematic diagram of the rotating shaft A of the present invention.

[0031] Figure 7 It is a system block diagram of the PLC controller of the present invention.

[0032] Numbers in the figure: 1. CO2 turbine body; 2. Insulation layer; 3. Insulation material (louver); 4. Fixed bracket; 5. Intake control valve; 6. Intake channel; 7. Exhaust channel; 8. Traction shaft; 9. Reserved hole; 10. Cooling fan; 11. Isolation valve; 12. Check valve baffle; 13. Muffler; 14. Electric motor; 15. Rolling shaft; 16. Traction rope; 17. Limit switch contact; 18. Movable bracket.

[0033] In the figure, T1 is the metal temperature of the turbine outer cylinder wall; T2 is the metal temperature of the turbine inner cylinder wall. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with embodiments.

[0035] like Figure 1-Figure 5 As shown, an automatically foldable supercritical carbon dioxide turbine insulation device and control method include a CO2 turbine body 1, an insulation layer 2 is attached to the outer wall of the CO2 turbine body 1, the insulation layer 2 adopts a louver-type insulation material 3, and the insulation material 3 is supported by a double-layer bracket of a fixed bracket 4 and a movable bracket 18; reserved holes 9 of different sizes and shapes are distributed on the insulation material 3 for installing the signal measurement element of the CO2 body; the insulation device also includes an external auxiliary equipment cooling fan 10, the cooling fan 10 is equipped with an isolation valve 11 and an intake control valve 5; the isolation valve 11 is a normally open valve, which is closed only during maintenance and long-term shutdown, and the intake control valve 5 adopts a pneumatic valve with a fast opening and closing function; the outlet of the cooling fan 10 and the CO2 turbine body 1 are connected to the exhaust channel 7 through the intake channel 6, and after being discharged from the exhaust channel 7, it passes through the check valve baffle 12 into the muffler 13 and is finally discharged to the atmosphere.

[0036] In this embodiment, if Figure 5 and Figure 6 As shown, the fixed bracket 4 and the louver-type thermal insulation material 3 are fixed by a traction shaft 8, and the local enlarged details of the traction shaft 8 are shown in FIG. Figure 6 As shown in A. The movable bracket 18 allows the louver-type heat-insulating material 3 to be propped up at an angle of 45°, so that circles of gas flow cavities are formed between the heat-insulating material 3 and the outer wall of the CO2 turbine body 1.

[0037] In this example, if Figure 5 As shown, the movable bracket 18 is connected to the rolling shaft 15 through a traction rope 16, and the rolling shaft 15 is driven by an electric motor 14. The maximum movable distance of the movable bracket 18 is contact with the limit switch contact 17. At this time, the angle between the movable bracket 18 and the insulation material 3 is the largest, which is 45°.

[0038] In this embodiment, if Figure 7 As shown, the automatic suspended supercritical CO2 insulation device is controlled by a PLC controller, which includes three groups of input signals (respectively turbine trip signal, temperature difference ΔT between inner and outer wall cylinders of turbine and limit switch contacts) and three groups of output signals (respectively running / stopping of electric motor, running / stopping of cooling fan and opening / closing of air intake control valve).

[0039] Control method:

[0040] Before starting the CO2 turbine 1, first confirm that Figure 2 The outlet isolation valve 11 of the intercooling fan 10 is in the fully open position, and then check whether the direction of the check valve baffle 12 is correct. Finally, the metal temperatures T1 and T2 of the inner and outer walls of the CO2 turbine body 1 are transmitted to ensure that the temperature origin is accurate and reliable.

[0041] The trip signal of the CO2 turbine body 1 is directly sent to the PLC controller through hard wiring, and the signal is a pulse signal.

[0042] Turbine inner and outer cylinder wall temperature difference ΔT control:

[0043] The temperature difference ΔT between the inner and outer walls of the turbine is obtained by subtracting the metal temperature T2 of the inner wall of the turbine from the metal temperature T1 of the outer wall of the turbine, that is, ΔT = T2-T1.

[0044] When ΔT>35℃, the "temperature difference ΔT between inner and outer wall of turbine" signal is triggered, that is, the signal transmitted to the PLC controller by hard wiring is "1";

[0045] When ΔT is less than 5°C, the "turbine inner and outer wall temperature difference ΔT" signal is reset, that is, the signal transmitted to the PLC controller through hard wiring is "0".

[0046] Electric motor 14 operating state control:

[0047] During the startup phase of the CO2 turbine body 1, that is, when the turbine trip signal is not sent, no matter how large the temperature difference ΔT between the inner and outer walls of the turbine is, the electric motor 14 will not be triggered to run.

[0048] When and only when the PLC controller receives the turbine trip signal and the temperature difference between the inner and outer wall cylinders of the turbine ΔT>35°C at the same time, the electric motor 14 is triggered to run;

[0049] After the electric motor 14 is running, the movable bracket 18 of the heat-insulating louver starts to rotate along the rolling axis 15 under the pulling force of the traction rope 16. When the limit switch contact 17 on the movable bracket 18 is closed, the movable bracket 18 slides into place and the electric motor 14 stops. At this time, the angle between the movable bracket 18 and the heat-insulating material 3 is the largest, which is 45°.

[0050] Operation status control of cooling fan 10:

[0051] When the limit switch contact 17 on the movable bracket 18 is closed, the cooling fan 10 starts automatically;

[0052] When the closing signal of the limit switch contact 17 on the movable bracket 18 disappears, the cooling fan 10 automatically stops. The louver-type thermal insulation material gradually returns to the folded state under the action of gravity.

[0053] Switching state control of intake control valve 5:

[0054] When the cooling fan 10 is started, the air intake control valve 5 is automatically opened after a delay of 2 seconds;

[0055] When the cooling fan 10 stops, the air intake control valve 5 is automatically closed after a delay of 2 seconds.

[0056] Switching state control of the cooling fan 10 outlet isolation valve:

[0057] The cooling fan 10 outlet isolation valve adopts a manual stop valve.

[0058] Before starting the unit, it should be manually set to the full open position according to the inspection card;

[0059] When the unit is under overhaul or out of service for a long time, manually set it to the fully closed position according to the inspection card.

[0060] The above description is only a preferred embodiment of the invention and is not intended to limit the invention. Although the invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the invention should be included in the protection scope of the invention.

Claims

1. An automatically stackable supercritical carbon dioxide turbine insulation device, characterized in that: The invention comprises a CO2 turbine body (1), the outer wall of the CO2 turbine body (1) is attached with a heat-insulating layer (2), the heat-insulating layer (2) adopts a heat-insulating material (3) distributed in a louvered pattern, the heat-insulating material (3) is supported by a double-layer support of a fixed support (4) and a movable support (18), the heat-insulating material (3) is provided with reserved holes (9) of different sizes and shapes, and the reserved holes (9) are used to install a signal measuring element of the CO2 body; The fixed bracket (4) is a high temperature resistant metal strip, which is attached to the outer wall along the radial direction of the turbine, arranged at intervals, and surrounds the outer wall of the turbine. The fixed bracket (4) and the heat insulating material (3) are fixed by a traction shaft (8). The movable bracket (18) is used to support the heat insulating material (3). The angle between the lower edge surface of the heat insulating material and the outer wall of the turbine can be up to 45 degrees, so that layers of surrounding gas flow cavities are formed between the heat insulating material (3) and the outer wall of the CO2 turbine body (1); The movable bracket (18) is a high-temperature resistant metal strip, which is arranged at intervals along the turbine axis and connected to the rolling shaft (15) through a traction rope (16). The rolling shaft (15) is driven by an electric motor (14). The maximum movable distance of the movable bracket (18) is to contact with the limit switch contact (17). At this time, the maximum angle between the movable bracket (18) and the insulation material (3) is 45°.

2. The automatically stackable supercritical carbon dioxide turbine insulation device according to claim 1, characterized in that: The CO2 turbine body (1) is provided with an air intake channel (6) and an air exhaust channel (7); the air intake channel (6) is connected to the outlet of a cooling fan (10); an isolation valve (11) and an air intake control valve (5) are provided between the cooling fan (10) and the air intake channel (6); the exhaust channel (7) is connected to a muffler (13) via a pipeline, and a check valve baffle (12) is provided on the pipeline.

3. The automatically stackable supercritical carbon dioxide turbine insulation device according to claim 2, characterized in that: The air intake control valve (5) is a pneumatic valve.

4. A control method for an automatically foldable supercritical carbon dioxide turbine insulation device according to any one of claims 1 to 3, characterized in that: The steps include: The heat preservation device is controlled by a PLC controller, and the PLC controller includes three groups of input signals and three groups of output signals, namely, a trip signal in1 of the CO2 turbine body (1), a temperature difference ΔT in2 between the inner and outer wall cylinders of the CO2 turbine body (1), and a limit switch contact in3; an operation / stop signal out1 of the electric motor (14), an operation / stop signal out2 of the cooling fan (10), and an opening / closing signal out3 of the air intake control valve (5); The temperature difference ΔTin2 between the inner and outer walls of the CO2 turbine body (1) is obtained by the difference between the metal temperature T2 of the inner wall of the turbine and the metal temperature T1 of the outer wall of the turbine, that is, ΔT = T2 - T1; During the start-up phase of the CO2 turbine body (1), that is, when the turbine trip signal in1 is not sent, no matter how large the temperature difference ΔTin2 between the inner and outer walls of the turbine is, the electric motor (14) will not be triggered to operate; When the PLC controller simultaneously receives the turbine trip signal (in1) and the temperature difference between the inner and outer cylinder walls of the turbine ΔT>35°C in2, the electric motor (14) is triggered to run; when the limit switch contact (17) on the movable bracket (18) is closed, the movable bracket (18) slides into place and the electric motor (14) stops; When the limit switch contact (17) on the movable bracket (18) is closed, the cooling fan (10) automatically starts; after the cooling fan (10) automatically starts, the air intake control valve (5) is interlocked and opened, and during the normal operation of the unit, the outlet isolation valve (11) of the cooling fan (10) remains in a normally open state.

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