An operating system and operating method for preventing a compressor from entering the liquid phase

Abstract

The present invention discloses an operation system and an operation method for preventing a compressor from entering a liquid phase. During full-load operation, the carbon dioxide exhaust gas after turbine work and heat exchange passes through the hot side of a cooler, exchanges heat with a cooling medium on the cold side, cools down and enters a pressure-stabilizing tank, and then enters an outlet main pipe through an outlet, enters a compressor inlet for pressure boosting, and adjusts the compressor inlet pressure through a compressor inlet pressure control system to ensure a stable system back pressure. During cold start-up, the compressor inlet pressure is increased by a high-pressure gas source and a supplementary gas source control valve, and then the pressure of the entire circulation system is increased through the compressor, and the compressor inlet temperature is ensured to be sufficiently low through the cooler temperature control system so that the compressor has a maximum operating efficiency, thereby ensuring that the compressor inlet does not enter a liquid phase interval for operation, protecting the compressor operation economy and safety and reliability to the greatest extent, and ensuring the safe and stable operation of a supercritical carbon dioxide power generation system.

Description

Technical Field

[0001] The present invention relates to the technical field of supercritical carbon dioxide cycle power generation, and particularly relates to an operating system and an operating method for preventing a compressor from entering the liquid phase. Background Art

[0002] With the development of power generation technology, supercritical carbon dioxide, as an excellent working medium to replace steam, has come into the view of many researchers due to its higher cycle efficiency, more compact equipment layout, and more economical upfront investment. During the simulation experiment process, it was found that: the compressor, as the core auxiliary equipment for supercritical carbon dioxide cycle power generation, although having a similar function to the feed water pump in the traditional steam cycle, actually has quite large differences.

[0003] As one of the main components of the supercritical carbon dioxide cycle power generation system, the operating conditions of the compressor have relatively high requirements. When the inlet temperature and pressure of the compressor are lower than the critical point, the problem of transcritical operation will occur; when the inlet and outlet temperatures and pressures of the compressor are too high, due to the strong coupling of the closed cycle, the overall system parameters will increase, which will have an adverse impact on the entire system equipment. Therefore, in the operation control of the supercritical carbon dioxide power generation system, when the inlet and outlet pressures or temperatures of the compressor exceed the limit values or other factors cause potential safety hazards, there is a high probability that due to the too low inlet temperature of the compressor, or even the risk of entering the liquid phase range for operation, which will cause irreversible damage to the compressor blades and shafting, thus leading to the risk of shutdown of the supercritical carbon dioxide power generation system. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the present invention provides an operating system and an operating method for preventing a compressor from entering the liquid phase, thereby ensuring that the inlet of the compressor does not enter the liquid phase range for operation, protecting the economic operation and safety reliability of the compressor to the greatest extent, and ensuring the safe and stable operation of the supercritical carbon dioxide power generation system.

[0005] The present invention is realized through the following technical solutions:

[0006] An operating system for preventing a compressor from entering the liquid phase includes a pressure stabilizing tank, a compressor, a cooler, a compressor inlet pressure control system, and a cooler temperature control system;

[0007] The outlet of the working medium side of the cooler is connected to the inlet of the pressure stabilizing tank through a pipeline. One end of the outlet of the pressure stabilizing tank is connected to the compressor through a pipeline, and the other end of the outlet of the pressure stabilizing tank is connected to a pressure stabilizing tank drain valve. A supplementary gas source control valve is provided on the outlet pipeline of the pressure stabilizing tank. One end of the high-pressure gas source is connected to the pressure stabilizing tank, and the other end of the high-pressure gas source is provided with a cooler bypass valve; a cooling medium control valve is provided at the outlet of the cooling medium side pipeline of the cooler;

[0008] A pressure sensor assembly and a first temperature sensor assembly are provided at the inlet of the compressor, and a second temperature sensor assembly and a flow sensor assembly are provided at the inlet of the cooler; the compressor inlet pressure control system is respectively connected to the pressure sensor assembly, the first temperature sensor assembly, the supplementary gas source control valve and the pressure stabilizing tank evacuation valve; the cooler temperature control system is respectively connected to the cooling medium control valve, the cooler bypass valve, the second temperature sensor assembly and the flow sensor assembly.

[0009] Preferably, it includes a pressure stabilizing tank a and a pressure stabilizing tank b. The working medium side outlet of the cooler is respectively connected to the inlets of the pressure stabilizing tank a and the pressure stabilizing tank b through pipelines. The outlets of the pressure stabilizing tank a and the pressure stabilizing tank b are respectively connected to the outlet main pipeline through pipelines. The pressure stabilizing tank a and the pressure stabilizing tank b are connected through a connecting pipeline.

[0010] Preferably, isolation valves are provided between the outlets and inlets of the pressure stabilizing tank a and the pressure stabilizing tank b;

[0011] Preferably, the cooler is a heat exchanger. The hot side of the cooler is carbon dioxide waste gas, and the cold side of the cooler is a cooling medium. The heat exchanger is a shell-and-tube heat exchanger and a plate heat exchanger.

[0012] An operation method for preventing the compressor from entering the liquid phase includes,

[0013] During the full-load operation process, the carbon dioxide waste gas after turbine work and heat exchange passes through the hot side of the cooler, and after heat exchange with the cooling medium on the cold side, it cools down and enters the pressure stabilizing tank, and then enters the inlet of the compressor to boost the pressure. At this time, the compressor inlet pressure control system adjusts the inlet pressure of the compressor. Specifically:

[0014] Judge whether it is in the supercritical working state through the set critical point value. If the compressor does not meet the conditions for entering the supercritical working state, the quasi-liquid temperature fitted at this pressure should be calculated through the pseudo-critical temperature. By comparing the inlet temperature of the compressor with the quasi-liquid temperature, judge in turn whether the compressor reaches the shutdown condition, the overpressure alarm condition and the low-temperature alarm condition, and the results are fed back to the cooler temperature control system. After being adjusted by the cooler temperature control system, it acts on the compressor inlet pressure control system again;

[0015] During the cold start process, the inlet pressure of the compressor is increased by the high-pressure gas source and the supplementary gas source control valve, and then the entire circulation system pressure is increased through the compressor. At this time, the cooler temperature control system adjusts the temperature of the cooling medium in the cooler to judge whether to put the cooler into operation. Specifically:

[0016] The compressor inlet temperature and set temperature are corrected by the temperature of the cooler and judged through the low temperature alarm to determine whether they are in the liquid phase range; if there is no low temperature alarm, the cooler response is adjusted to feedback to the set temperature; if there is a low temperature alarm, the cooler response is used to adjust the working fluid flow of the cooler, and the working fluid rate is judged at the same time; if the working fluid replenishment rate exceeds the safety range, the cooler bypass response sends an instruction, and the cooler bypass valve adjusts the operating mode of the cooling medium.

[0017] Preferably, if the inlet temperature of the compressor and the quasi-liquid phase temperature do not meet the shutdown conditions, the triggering conditions of the overpressure alarm condition and the low temperature alarm condition, the compressor inlet pressure control system is automatically reset.

[0018] Preferably, when the compressor inlet temperature triggers a low temperature alarm, the supplementary air source control valve corresponding to the supplementary air source must be locked.

[0019] Preferably, when the compressor inlet pressure is higher than a set critical point, there is no risk of liquid phase operation.

[0020] Preferably, when the compressor needs to operate at a low temperature, the automatic operation mode of the cooler temperature control system is forcibly released and switched to manual operation, and only the bypass response, overpressure alarm and shutdown alarm are retained as protective means for system regulation.

[0021] Preferably, when the inlet pressure of the compressor is in an abnormal state and an overpressure alarm is triggered, the drain valve of the pressure-stabilizing tank opens quickly to discharge part of the working fluid into the atmosphere to stabilize the inlet pressure of the compressor.

[0022] Compared with the prior art, the present invention has the following beneficial technical effects:

[0023] The present invention provides an operation system and an operation method for preventing a compressor from entering a liquid phase. During full-load operation, the carbon dioxide exhaust gas after turbine work and heat exchange passes through the hot side of a cooler, exchanges heat with a cooling medium on the cold side, cools down and enters a pressure-stabilizing tank, and then enters an outlet main pipe through an outlet, enters a compressor inlet for pressure boosting, and adjusts the compressor inlet pressure through a compressor inlet pressure control system to ensure a stable system back pressure. During cold start-up, the compressor inlet pressure is increased by a high-pressure gas source and a supplementary gas source control valve, and then the pressure of the entire circulation system is increased through the compressor, and the compressor inlet temperature is ensured to be sufficiently low through the cooler temperature control system so that the compressor has a maximum operating efficiency, thereby ensuring that the compressor inlet does not enter a liquid phase interval for operation, protecting the compressor operation economy and safety and reliability to the greatest extent, and ensuring the safe and stable operation of a supercritical carbon dioxide power generation system.

[0024] Furthermore, isolation valves are provided between the inlets and outlets of the two pressure stabilizing tanks. During operation, if a single storage tank fails, it can be isolated through the manual valves at the inlets and outlets of the pressure stabilizing tank itself. After all the manual valves of the tank body are closed, the pressure stabilizing tank is taken out of operation. Pressure relief and evacuation operations can be carried out, which is convenient for maintenance.

[0025] Furthermore, the cooler should appropriately reduce the flow rate and moderately increase the inlet temperature to prevent overpressure alarms triggered by pressure fluctuations or the compressor from operating in the liquid phase range.

[0026] Furthermore, the high-pressure carbon dioxide in the high-pressure gas source is controlled in pressure by the supplementary gas source control valve and is fed into the pressure stabilizing tank via the connecting pipeline between the pressure stabilizing tanks. The supplementary gas source is only used during the cold start process. During normal operation, it only serves as a means to stabilize the inlet pressure and an external gas source to balance the leakage.

[0027] Furthermore, in special cases, when the compressor needs to operate under low-temperature parameters, the automatic operation mode of the cooler temperature control system is forced to be lifted and changed to manual operation by the low-temperature alarm. Only the bypass response, overpressure alarm, and shutdown alarm are retained as adjustment and protection means for the system.

[0028] Furthermore, the rate judgment in the cooler gas temperature control system needs to be set in combination with parameters such as the diameters of the cold side and hot side of the cooler and the heat transfer efficiency. When the bypass responds and the cooler bypass valve opens, the bypass pipe diameter selection must match the flow rate to ensure that while adjusting the flow rate of the cooling medium, the minimum flow rate entering the cooler is guaranteed to prevent the cooler from being damaged due to overheating. It is recommended to select a 50% flow rate for bypass with a cut-off or a 100% flow rate bypass with a regulating valve to increase the adjustment accuracy for the cooling medium and the cooler. When the system is operating normally, the cooler bypass valve remains fully closed and does not participate in the adjustment.

[0029] Furthermore, when the compressor inlet is in an abnormal state and the overpressure alarm is triggered, the pressure stabilizing tank evacuation valve quickly opens to discharge part of the working medium into the atmosphere to stabilize the compressor inlet pressure. The selection of the pressure stabilizing tank evacuation valve and its evacuation pipeline diameter should meet the following conditions: a discharge pressure rate of ≥1.5 MPa / min, and the pressure stabilizing tank evacuation valve has a certain adjustable margin. In the specific implementation process, a regulating valve can be selected for the evacuation valve, which has better accuracy, and an interlock closing time or pressure value should be set to ensure the minimum impact on the inlet pressure under accident conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the flow chart of the related equipment for preventing the compressor from entering the liquid phase of the present invention;

[0031] Figure 2 is the flow chart of the compressor inlet pressure control system of the present invention;

[0032] Figure 3Flow chart of the cooler temperature control system of the present invention;

[0033] In the figure: cooler 1, pressure stabilizing tanks 2a and 2b, compressor 3, cooling medium control valve 4, cooler bypass valve 5, high-pressure gas source 6, make-up gas source control valve 7, pressure stabilizing tank vent valve 8. Specific implementation manners

[0034] The following further elaborates on the present invention with specific embodiments, which is an explanation rather than a limitation of the present invention.

[0035] The following detailed descriptions are all explanations of the embodiments, aiming to provide further details of the present invention. Unless otherwise specified, all technical terms adopted by the present invention have the same meanings as commonly understood by those of ordinary skill in the art to which this application belongs. The terms used in the present invention are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention.

[0036] Based on the above considerations, while ensuring low temperature and high pressure of the compressor, it is ensured that the compressor does not enter the liquid phase range for operation. The technical solution adopted by the present invention: a method for preventing a compressor from entering the liquid phase in the context of supercritical carbon dioxide power generation. It includes: the equipment layout of the storage tank - compressor - cooler related to the actual equipment and the compressor inlet pressure control system responsible for regulating the response.

[0037] Such as Figure 1As shown in the figure, the main equipment system includes: a cooler 1, a pressure stabilizing tank 2a, a pressure stabilizing tank 2b, a compressor 3, a cooling medium control valve 4, a cooler bypass valve 5, a high-pressure gas source 6, and a pressure stabilizing tank evacuation valve 8. Among them, the working medium side outlet of the cooler 1 is connected to the pressure stabilizing tank 2a and the pressure stabilizing tank 2b through pipelines respectively, and the tank body outlets of the pressure stabilizing tank 2a and the pressure stabilizing tank 2b are connected to the outlet main pipeline through pipelines respectively. The pressure stabilizing tank 2a and the pressure stabilizing tank 2b are connected through a pipeline, and the high-pressure gas source 6 is connected to the connecting pipeline between the pressure stabilizing tank 2a and the pressure stabilizing tank 2b through a supplementary gas source control valve 7. One end of the main pipeline of the tank body outlet is connected to the inlet of the compressor 3 through a pipeline, and the other end is connected to the pressure stabilizing tank evacuation valve 8 through a pipeline. Regarding the type of the evacuation valve 8, there is no specific requirement, it can be pneumatic or electric, as long as the remote operation is reliable. For the supplementary gas source control valve 7, there is no specific requirement, it can be pneumatic or electric, as long as the remote operation is reliable. The cooler 1 is a heat exchanger, the hot side is the carbon dioxide waste gas after turbine work and heat exchange, and the cold side is the cooling medium. There is no specific requirement for the cooling medium, it can be water, air, oil, etc.; the form of the heat exchanger is also not specifically required, it can be a shell-and-tube heat exchanger, a plate heat exchanger, etc. The pipeline outlet on the cooling medium side of the cooler 1 is equipped with a cooling medium control valve 4, and the inlet and outlet of the cooling side pipeline of the cooler 1 are connected by a pipeline. For the cooling medium control valve 4, there is no specific requirement, it can be pneumatic or electric, as long as the remote operation is reliable. The pipeline is equipped with a cooler bypass valve 5, there is no specific requirement, it can be pneumatic or electric, as long as the remote operation is reliable. For the cooling bypass, the pipe diameter flow should be controlled at about 50% of the main pipeline to ensure the safety of the heat exchanger 1 during operation and prevent overheating. The cooling medium control valve 4 and the cooler bypass valve 5 are preferably selected as regulating valves, and the action result and feedback accuracy are reliable. A pressure sensor assembly and a first temperature sensor assembly are provided at the inlet of the compressor, and a second temperature sensor assembly and a flow sensor assembly are provided at the inlet of the cooler; the compressor inlet pressure control system is respectively connected to the pressure sensor assembly, the first temperature sensor assembly, the supplementary gas source control valve and the pressure stabilizing tank evacuation valve; the cooler temperature control system is respectively connected to the cooling medium control valve, the cooler bypass valve, the second temperature sensor assembly and the flow sensor assembly.

[0038] The compressor inlet parameter comprehensive control system includes: a compressor inlet pressure control system A and a cooler temperature control system B.

[0039] As Figure 2 As shown in the figure, the compressor inlet pressure control system A includes: a compressor inlet pressure A1, a critical point judgment A2, a pseudo-temperature calculation A3, temperature comparison modules A4, A5, A6, a compressor shutdown A7, an inlet overpressure alarm A8, an inlet low-temperature alarm A9, and an automatic reset A10.

[0040] As Figure 3As shown in the figure, the cooler temperature control system B includes: compressor inlet temperature B1, temperature setting B2, cooler temperature correction B3, low-temperature alarm B4, cooler response B5, rate judgment B6, flow monitoring B7, bypass response B8, and automatic reset B9.

[0041] The specific operation mode of the main equipment: The carbon dioxide waste gas after turbine work and heat exchange passes through the hot side of the cooler, exchanges heat with the cooling medium on the cold side, cools down and enters the pressure stabilizing tanks 2a and 2b, and then enters the compressor 3 inlet to boost pressure after merging into the outlet header through the outlet. The cold-state working medium can also be emptied into the atmosphere through the pressure stabilizing tank drain valve 8 at the other end of the compressor inlet header. Isolation valves are provided between the inlets and outlets of the pressure stabilizing tanks 2a and 2b for isolating system pressure maintenance and are fully open during normal operation. The high-pressure carbon dioxide in the high-pressure gas source 6 controls the pressure through the makeup gas control valve 7 and is merged into the pressure stabilizing tanks 2a and 2b through the connecting pipeline between the pressure stabilizing tanks 2a and 2b. When the cooler is working, the cooling medium control valve 4 adjusts the flow rate of the cooling medium by adjusting its own opening. When the system is operating normally, the cooler bypass valve 5 remains fully closed.

[0042] The working mode of the compressor inlet pressure control system A: The compressor inlet pressure A1 determines whether it is in the "supercritical working state" through the critical point judgment A2 in the control logic. If it does not meet the condition to enter the "supercritical working state", the quasi-temperature calculation A3 should be carried out to obtain the quasi-liquid temperature fitted at this pressure. By comparing the inlet temperature B1 with the result after the quasi-temperature calculation A3, temperature comparison modules A4, A5, and A6 are used. The temperature comparison module A4 judges whether the shutdown condition is reached, the temperature comparison module A5 judges whether the overpressure alarm A7 is reached, and the temperature comparison module A6 judges whether the low-temperature alarm A8 is reached. At the same time, the overpressure alarm A9 interlocks with the pressure stabilizing tank drain valve 8; the low-temperature alarm A8 is fed back to the cooler temperature control system B. After being adjusted by the cooler temperature control system B, it acts on the compressor inlet pressure control system A again. Conversely, if the main system does not meet the triggering conditions of the temperature comparison modules A4, A5, and A6, the automatic reset A10 is activated. It should be noted that in order to ensure reliable operation of the pressure control system during actual operation, the quasi-critical temperature calculation A3 should be fitted within the working range of the compressor inlet pressure A1.

[0043] The working mode of the cooler temperature control system B: The temperature B1 at the compressor inlet and the set temperature B2, after being corrected by the cooler temperature correction B3, pass through the low-temperature alarm B4 to determine whether it is approaching or already in the liquid-phase range. The low-temperature alarm B4 has two channels: the low-temperature alarm A8 in the compressor inlet pressure control system A and the low-temperature alarm at the working medium outlet of the cooler 1 body. After being judged by the low-temperature alarm B4, if there is no low-temperature alarm, it is adjusted through the cooler response B5 and fed back to the set temperature B2; otherwise, the amount of cooling working medium is adjusted through the cooler response B5, and at the same time, the rate judgment B6 is carried out. After the rate exceeds the safe range, the bypass response B8 is required to act on the cooler bypass valve 5 in the main system. During the adjustment process of the cooler response B5, the flow monitoring B7 has two functions: ensuring the minimum safe flow of the cooler 1 and ensuring that the hot side of the cooler 1 does not overheat; ensuring that the cooling medium circulation system does not operate overpressure. During operation, through the bypass response B8 instruction, the cooler bypass valve 5 in the main system adjusts the operation mode of the cooling medium. After the temperature B1 at the compressor inlet and the cooler temperature correction B3 both enter the normal range, the low-temperature alarm signal is reset through the automatic reset B9.

[0044] Embodiment 1:

[0045] In a supercritical carbon dioxide cycle power generation system, it is applicable to cycle systems under different working conditions to prevent the compressor from entering the liquid phase.

[0046] During the cold start process, the inlet pressure A1 of the compressor 3 is increased by the high-pressure gas source 6 and the supplementary gas source control valve 7, and then the pressure of the entire cycle system is increased through the compressor 3. During this process, the temperature of the cooling medium is required to determine whether to put the cooler 1 into operation. If the temperature of the cooling medium is too low, it will trigger the inlet overpressure alarm A8 and the inlet low-temperature alarm A9, affecting the pressure increase rate. Therefore, the opening of the cooling medium control valve 4 should be controlled as much as possible in the early stage of cold start, and the cooler bypass valve 5 should be used when necessary to reduce the cooling medium entering the cooler 1. For the pseudo-critical temperature under different pressures, the system pseudo-temperature calculation A3 in the compressor inlet pressure control A is required.

[0047] During the full-load operation process, the carbon dioxide waste gas after the turbine does work and heat exchange passes through the hot side of the cooler, is cooled by the cooling medium on the cold side, and then enters the pressure stabilizing tanks 2a and 2b after cooling, and then enters the compressor 3 inlet to increase the pressure after merging into the outlet header through the outlet. During this process, it is determined by the critical point judgment A2 whether the system enters the "supercritical state operation", that is, the inlet pressure A1 is higher than the critical point pressure and the inlet temperature B1 is higher than the critical point temperature. When the inlet parameters of the compressor 3 are higher than the critical point parameters, there is no risk of liquid-phase operation.

[0048] When the compressor 3 inlet is in an abnormal state and the overpressure alarm A8 is triggered, the pressure-sustaining tank drain valve 8 opens quickly to discharge part of the working fluid into the atmosphere to stabilize the compressor 3 inlet pressure A1. The selection of the pressure-sustaining tank drain valve 8 and its drain pipe diameter should meet the following conditions: a discharge pressure rate of ≥1.5MPa / min and a certain adjustable margin of the pressure-sustaining tank drain valve 8. In the specific implementation process, the drain valve can choose to use a regulating valve, which has better accuracy, and it is advisable to set the interlock closing time or pressure value to ensure that the inlet pressure A1 is minimally affected under accident conditions.

[0049] When the inlet parameters of compressor 3 trigger the low temperature alarm A9, the supplementary air source control valve 7 corresponding to the supplementary air source must be locked to prevent the inlet of compressor 3 from quickly entering the liquid phase due to the pressure increase. The rate judgment B6 in the cooling air temperature control system B needs to be set in combination with the cold side and hot side pipe diameters of the cooler and the heat exchange efficiency and other parameters. When the bypass responds, the cooler bypass valve 5 opens, and the bypass pipe diameter selection must match the flow rate to ensure that while adjusting the cooling medium flow rate, the minimum flow rate entering the cooler 1 is guaranteed to prevent the cooler 1 from overheating and damage. It is recommended to select a 50% flow rate with cutoff for the bypass, or a 100% flow rate bypass with a regulating valve to increase the regulation accuracy for the cooling medium and cooler 1. Note: When the system is operating normally, the cooler bypass valve 5 remains fully closed and does not participate in the regulation.

[0050] There are isolation valves between each inlet and outlet of the surge tank 2a and the surge tank 2b. During operation, if a single storage tank fails, it can be isolated through the manual inlet and outlet doors of the surge tank itself. After all the manual doors of the tank body are closed, the surge tank will exit operation. Pressure relief and emptying operations can be performed to facilitate maintenance.

[0051] At this time, only a single pressure stabilizing tank is running, and the stability of the main system is reduced. It is not suitable to make large-scale load adjustments. It is recommended to maintain the current load condition. Cooler 1 should appropriately reduce the flow rate and moderately increase the inlet temperature B1 to prevent the triggering of overpressure alarm A8 or compressor 3 entering the liquid phase interval due to pressure fluctuations.

[0052] For the supplementary gas source, the high-pressure carbon dioxide in the high-pressure gas source 6 controls the pressure through the supplementary gas source control valve 7, and flows into the pressure stabilizing tank 2a and the pressure stabilizing tank 2b through the connecting pipeline between the pressure stabilizing tank 2a and the pressure stabilizing tank 2b. The supplementary gas source is only used during the cold start process. During normal operation, it is only used as a means to stabilize the inlet pressure A1 and an external gas source to balance the leakage. Therefore, the supplementary gas source control valve 7 should use a regulating valve with better adjustment accuracy.

[0053] In special cases, the compressor needs to operate under low temperature parameters. At this time, the low temperature alarm A9 forces the automatic operation mode of the cooler temperature control system B to be released and switched to manual operation. Only the bypass response B8, overpressure alarm A8 and shutdown alarm A7 are retained as the system adjustment and protection means.

[0054] Adjust the inlet pressure of the compressor through the compressor inlet pressure control system A to ensure the stability of the system back pressure; ensure that the inlet temperature of the compressor is low enough through the cooler temperature control system B so that the compressor has the maximum operating efficiency, and at the same time ensure that the inlet of the compressor does not operate in the liquid phase range, protecting the operation of the compressor economically and safely to the greatest extent.

[0055] The above is only the preferred embodiment of the present invention, and does not impose any form of limitation on the present invention; any ordinary technician in the industry can smoothly implement the present invention according to the description shown in the accompanying drawings of the specification and the above description; however, any minor changes, modifications and equivalent variations made by those skilled in the art within the scope of the technical solution of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications and variations made to the above embodiments based on the essential technology of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. An operating system for preventing a compressor from entering the liquid phase, characterized in that, It includes a pressure stabilizing tank, a compressor (3), a cooler (1), a compressor inlet pressure control system, and a cooler temperature control system; The working medium side outlet of the cooler (1) is connected to the inlet of the pressure stabilizing tank through a pipeline. One end of the outlet of the pressure stabilizing tank is connected to the compressor (3) through a pipeline, and the other end of the outlet of the pressure stabilizing tank is connected to the pressure stabilizing tank drain valve (8). A makeup gas source control valve (7) is provided on the outlet pipeline of the pressure stabilizing tank. One end of the high-pressure gas source (6) is connected to the pressure stabilizing tank, and a cooler bypass valve (5) is provided at the other end of the high-pressure gas source (6); A cooling medium control valve (4) is provided at the outlet of the cooling medium side pipeline of the cooler (1); A pressure sensor assembly and a first temperature sensor assembly are provided at the inlet of the compressor. A second temperature sensor assembly and a flow sensor assembly are provided at the inlet of the cooler (1); The compressor inlet pressure control system is respectively connected to the pressure sensor assembly, the first temperature sensor assembly, the makeup gas source control valve (7), and the pressure stabilizing tank drain valve (8); The cooler temperature control system is respectively connected to the cooling medium control valve (4), the cooler bypass valve (5), the second temperature sensor assembly, and the flow sensor assembly; The compressor inlet pressure control system includes: compressor inlet pressure A1, critical point judgment A2, pseudo-temperature calculation A3, temperature comparison modules A4, A5, A6, compressor shutdown A7, inlet overpressure alarm A8, inlet low-temperature alarm A9, automatic reset A10; The cooler temperature control system includes: compressor inlet temperature B1, temperature setting B2, cooler temperature correction B3, low-temperature alarm B4, cooler response B5, rate judgment B6, flow monitoring B7, bypass response B8, automatic reset B9.

2. The operating system for preventing a compressor from entering the liquid phase according to claim 1, wherein The pressure stabilizing tank includes a pressure stabilizing tank (2a) and a pressure stabilizing tank (2b). The working medium side outlet of the cooler (1) is respectively connected to the inlets of the pressure stabilizing tank (2a) and the pressure stabilizing tank (2b) through pipelines. The outlets of the pressure stabilizing tank (2a) and the pressure stabilizing tank (2b) are respectively connected to the outlet main pipeline through pipelines. A connection pipeline is provided between the pressure stabilizing tank (2a) and the pressure stabilizing tank (2b).

3. The operating system for preventing a compressor from entering the liquid phase according to claim 2, wherein Isolation valves are provided between the outlets and inlets of the pressure stabilizing tank (2a) and the pressure stabilizing tank (2b).

4. The operating system for preventing a compressor from entering a liquid phase according to claim 1, characterized in that, The cooler (1) is a heat exchanger. The hot side of the cooler (1) is carbon dioxide waste gas, and the cold side of the cooler (1) is a cooling medium. The heat exchanger is a shell-and-tube heat exchanger and a plate heat exchanger.

5. An operating method for preventing a compressor from entering the liquid phase, based on the operating system for preventing a compressor from entering the liquid phase according to any one of claims 1-4, characterized in that, including, During the full-load operation process, the carbon dioxide waste gas after turbine work and heat exchange passes through the hot side of the cooler, is cooled by the cooling medium on the cold side, enters the pressure stabilizing tank after temperature reduction, and then enters the inlet of the compressor (3) for pressure boost. At this time, the compressor inlet pressure control system adjusts the inlet pressure of the compressor (3). Specifically: Determine whether it is in the supercritical operating state by the set critical point value. If the compressor (3) does not meet the conditions for entering the supercritical operating state, the quasi-liquid temperature fitted at this pressure should be obtained through the calculation of the pseudo-critical temperature; by comparing the inlet temperature of the compressor (1) with the quasi-liquid temperature, successively judge whether the compressor (3) meets the shutdown conditions, overpressure alarm conditions and low-temperature alarm conditions, and the results are fed back to the cooler temperature control system, and after being adjusted by the cooler temperature control system, it acts on the compressor inlet pressure control system again; During the cold start process, the inlet pressure of the compressor (3) is increased by the high-pressure gas source (6) and the supplementary gas source control valve (7), and then the pressure of the entire circulation system is increased through the compressor (3). At this time, by adjusting the temperature of the cooling medium in the cooler (1) by the cooler temperature control system, it is judged whether to put the cooler (1) into operation. Specifically: After correcting the temperature of the cooler (1), the inlet temperature of the compressor (3) and the set temperature are judged whether it is in the liquid phase range through the low-temperature alarm judgment; If there is no low-temperature alarm, it is fed back to the set temperature through the response adjustment of the cooler (1); if there is a low-temperature alarm, the working medium flow rate of the cooler (1) is adjusted through the response of the cooler (1), and at the same time, the working medium rate is judged; if the working medium replenishment rate exceeds the safe range, an instruction issued by the response of the cooler bypass is used to adjust the operation mode of the cooling medium by the cooler bypass valve (5).

6. A method for preventing a compressor from entering the liquid phase according to claim 5, characterized in that, If the comparison between the inlet temperature of the compressor (1) and the quasi-liquid temperature does not meet the triggering conditions of the shutdown conditions, overpressure alarm conditions and low-temperature alarm conditions, the compressor inlet pressure control system will be automatically reset.

7. A method for preventing a compressor from entering the liquid phase according to claim 5, characterized in that, When the low-temperature alarm is triggered by the inlet temperature of the compressor (3), the supplementary gas source control valve (7) corresponding to the supplementary gas source is closed.

8. A method for preventing a compressor from entering the liquid phase according to claim 5, characterized in that, When the inlet pressure of the compressor (3) is higher than the set critical point, there is no risk of liquid phase operation.

9. A method for preventing a compressor from entering the liquid phase according to claim 5, characterized in that, When the compressor (1) needs to operate at low temperature, the automatic operation mode of the cooler temperature control system is forcibly cancelled and changed to manual operation, and only the bypass response, overpressure alarm and shutdown alarm are retained as the adjustment protection means of the system.

10. A method for preventing a compressor from entering the liquid phase according to claim 5, characterized in that, When the inlet pressure of the compressor (3) is in an abnormal state and the overpressure alarm is triggered, the pressure stabilizing tank drain valve (8) quickly opens to discharge part of the working medium into the atmosphere to stabilize the inlet pressure of the compressor (3).

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