Supercritical carbon dioxide cycle power generation system with water cooling structure

Abstract

The invention discloses a supercritical carbon dioxide cycle power generation system with a water cooling structure, which comprises a cooler, a heater, a compressor, a turbine and a generator, and further comprises a circulating pump and a water heat exchanger, the cooler, the circulating pump and the water heat exchanger are communicated through pipelines and form a main circulation loop of a coolant, a main loop regulating valve and a transmitter are arranged in the main circulation loop, the main loop regulating valve is arranged at a coolant inlet of the cooler, and the transmitter is arranged between the cooler and the compressor; and the transmitter and the main loop regulating valve are electrically connected with the input end and the output end of the control device respectively. According to the supercritical carbon dioxide cycle power generation system with the water cooling structure, a water pump frequency adjusting system, a water temperature adjusting system and the like are not needed, the water cooling structure is simple in composition, small in size and weight and low in energy consumption, and the equipment investment can be effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of supercritical carbon dioxide power generation, and in particular to a supercritical carbon dioxide circulation power generation system with a water cooling structure. Background Art

[0002] Supercritical carbon dioxide power generation technology is a new type of thermal power generation technology using carbon dioxide as the working fluid, with the advantages of high cycle efficiency and high power density. The inlet of the supercritical carbon dioxide compressor works near the critical point, and the physical properties change very drastically. During normal operation, the near-critical carbon dioxide working fluid has a large specific heat and a large flow rate, and requires a relatively large cooling capacity for the water system. When the system is started, the working fluid in the cooler is in a gaseous state, with a small flow rate and a very small specific heat, and requires a very small cooling capacity for the water system. In order to ensure the rated operating performance of the power generation system, the cooling capacity of the water system must be configured according to a large capacity, but the conventional cooling capacity adjustment range will cause the cooling capacity to be too large during startup, which will cause the compressor inlet to enter the gas-liquid two-phase region during the startup process, endangering the safety of the equipment. Therefore, the current common practice in the industry is to ensure the realization of extremely low cooling capacity during the startup process through configurations such as water temperature regulation, variable frequency water pumps, and multiple small-capacity cooling modules.

[0003] The invention patent with publication number CN114815918B discloses a supercritical carbon dioxide precooler temperature control system and method. The system and method require the use of multiple variable frequency water pumps, variable frequency fans and regulating valves to control the temperature of carbon dioxide in the precooler, resulting in a complex cooling water system structure, increased volume, weight and operating costs. Summary of the invention

[0004] In view of the above technical problems, the purpose of the present invention is to provide a supercritical carbon dioxide circulation power generation system with a water cooling structure, which is used to solve the technical problems of the existing cooling water system having a complex structure, large volume and weight, and high operating cost.

[0005] According to the supercritical carbon dioxide circulation power generation system with a water-cooling structure proposed by the present invention, the supercritical carbon dioxide circulation power generation system with a water-cooling structure includes a cooler, a heater, a compressor, a turbine and a generator, the working fluid outlet of the cooler is connected to the working fluid inlet of the compressor through a pipeline, the power generation system also includes a circulation pump and a water heat exchanger, the cooler, the circulation pump and the water heat exchanger are connected through a pipeline, and constitute a main circulation loop of the coolant, the main circulation loop is provided with a main loop regulating valve and a transmitter, the main loop regulating valve is arranged at the coolant inlet of the cooler, the transmitter is arranged between the cooler and the compressor, and the transmitter and the main loop regulating valve are electrically connected to the input end and the output end of the control device respectively;

[0006] The circulation pump and the water heat exchanger are also connected through a pipeline to form a bypass circulation loop of the coolant. A bypass regulating valve is provided in the bypass circulation loop. A flow meter is provided on the pipeline between the circulation pump and the water heat exchanger. The flow meter and the bypass regulating valve are electrically connected to the input end and the output end of the control device respectively.

[0007] After the internal units of the power generation system are started, the opening of the main circuit regulating valve is initially maintained at 0. When the working medium temperature at the cooler outlet exceeds T1°C, the main circuit regulating valve is in manual control mode, and the opening is fixed at 5-20%, maintained for at least 1 minute, and then put into automatic control. The control device automatically adjusts the opening of the main circuit regulating valve based on the difference between the measured value and the set value of the transmitter to control the working medium temperature at the cooler outlet.

[0008] In some embodiments, the transmitter is a temperature transmitter or a density transmitter.

[0009] In some embodiments, the circulation pump, the water heat exchanger and the heat exchanger in the lubricating oil station are connected by a pipeline to form a cooling branch of the lubricating oil station. A cooling branch regulating valve is provided on the cooling branch of the lubricating oil station, and the cooling branch regulating valve is electrically connected to the output end of the control device.

[0010] In some embodiments, the circulation pump, the water heat exchanger and the heat exchanger in the generator are connected through a pipeline to form a generator cooling branch, and the control valve on the generator cooling branch is electrically connected to the output end of the control device.

[0011] In some embodiments, the circulation pump, the water heat exchanger and the heat exchanger in the power conversion control cabinet are connected by a pipeline and constitute a cooling branch of the power conversion control cabinet. The control valve on the cooling branch of the power conversion control cabinet is electrically connected to the output end of the control device.

[0012] In some embodiments, the main circuit regulating valve is a dual-spool regulating valve.

[0013] In some embodiments, 45≤T1≤60.

[0014] In some embodiments, the cooler is a microchannel heat exchanger.

[0015] In some embodiments, the cooler is a printed circuit board heat exchanger.

[0016] In some embodiments, the cold side fluid of the water heat exchanger 3 is cooling water provided by a natural water source, air, or a circulating water system.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The supercritical carbon dioxide circulation power generation system with a water cooling structure proposed in the present invention does not require a water pump frequency adjustment system, a water temperature adjustment system, etc. The water cooling structure is simple in composition, small in structure volume and weight, and low in energy consumption, which can effectively reduce equipment investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The preferred implementation modes will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present invention.

[0020] Figure 1 It is a schematic structural diagram of a supercritical carbon dioxide cycle power generation system according to an embodiment of the present invention.

[0021] Figure 2 It is a schematic structural diagram of the main circulation loop portion of an embodiment of the present invention.

[0022] Figure 3 This is a temperature variation trend diagram of the compressor inlet after the power generation unit is started in one embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0024] Any substance has three phases: solid, liquid and gas. Under certain temperature and pressure, the phase of the substance will change, thus showing different phases. Among them, the point where the gas and liquid phases are in equilibrium is called the critical point. The temperature and pressure corresponding to the critical point are called the critical temperature and critical pressure respectively. The state of the substance at the critical point is called the critical state. If the temperature and pressure of the substance in the critical state continue to rise, when the temperature and pressure exceed the critical temperature and critical pressure, the substance no longer has a phase boundary between liquid and gas, and presents properties between liquid and gas, that is, the substance enters the supercritical state.

[0025] When the temperature and pressure of CO2 reach its critical temperature of 31.1°C and critical pressure of 7.38M1a respectively, CO2 will be in a supercritical state, that is, SCO2. SCO2 is between liquid and gas, and has the special physical properties of low gas viscosity and high liquid density, which gives it typical advantages such as good fluidity, high heat transfer efficiency, and low compressibility. Using SCO2 as a circulating working fluid for power generation has the characteristics of wide applicable heat sources, compact structure, low compression power consumption, and high cycle efficiency. It has the advantages of efficiency, volume, and flexibility that traditional steam power generation cannot match. It has broad application prospects in the fields of solar thermal utilization, coal-fired power generation, nuclear power generation, waste heat utilization, ship propulsion, etc. It is a new generation of high-efficiency, low-cost, and environmentally friendly advanced energy technology.

[0026] Figure 1 Schematic diagram of the structure of the supercritical carbon dioxide cycle power generation system in the embodiment of the present invention. Figure 1 As shown, the supercritical carbon dioxide circulation power generation system in the embodiment of the present invention includes a power generation unit and a reinjection unit.

[0027] The power generation unit is used to generate electricity using SCO2 as a working medium, and the power generation unit includes a compressor 1, a turbine 2, a generator 3, a regenerator 5 and a heater 6. The compressor 1, the turbine 2 and the generator 3 constitute a main engine system, which are fixed on the same rotating shaft, and the generator 3 is located between the turbine 2 and the compressor 1.

[0028] The compressor 1 is used to increase the low-pressure working medium (CO2) to a high-pressure working medium. The compressor 1 can be a screw compressor, a centrifugal compressor, an axial flow compressor, or a centrifugal + axial flow compressor, etc., which is not limited here. The compressor 1 is connected to the regenerator 5 through a pipeline 11. In the pipeline 11, the working medium flows from the compressor 1 side to the regenerator 5 side.

[0029] The regenerator 5 is also called a heat exchanger. Currently, most of the hot and cold sides flow continuously and exchange heat through the metal wall. The regenerator 5 has two functions in the SCO2 cycle. One is to heat the working fluid at the outlet of the compressor 1, save fuel, and improve thermal efficiency. The other is to reduce the temperature of the working fluid at the outlet of the turbine 2, reduce the use of cooling water, save water resources, and reduce the energy consumption of the compressor 1. In a possible implementation, the regenerator 5 can be a printed circuit board type regenerator. The regenerator 5 is connected to the heater 6 and the cooler 8 through the pipeline 12 and the pipeline 17 respectively. In the pipeline 12, the working fluid flows from the regenerator 5 side to the heater 6 side. In the pipeline 17, the working fluid flows from the regenerator 5 side to the cooler 8 side.

[0030] The heater 6 is used to heat the circulating working medium. The energy source of the heater 6 can be industrial waste heat, nuclear reactors, fossil fuels or solar energy, etc. In a possible implementation, the heater 6 can be a gas boiler heater. The heater 6 is connected to the turbine 2 through a pipeline 13. In the pipeline 13, the working medium flows from the heater 6 side to the turbine 2 side.

[0031] The cooler 8 is used to cool the working fluid so that the temperature of the working fluid is controlled within a preset range. Since the temperature of the working fluid entering the compressor 1 is relatively low, the inlet temperature of the compressor 1 can be effectively controlled to prevent damage to the compressor 1 and other equipment. The cooler 8 can use a microchannel cooling gas, such as a printed circuit board cooler, or a coil cooler, etc., which are not limited here. In the cooler 8, the coolant exchanges heat with the working fluid to remove the heat of the working fluid to lower the temperature of the working fluid. Specifically, the cooler 8 is connected to the compressor 1 via a pipe 18. In the pipe 18, the working fluid flows from the cooler 8 side to the compressor 1 side. Figure 2 As shown, the cooler 8 is also connected to the circulation pump 21 and the water heat exchanger 23 through a pipeline, and forms a main circulation loop of the coolant. In the main circulation loop, the coolant circulates between the circulation pump 21, the water heat exchanger 23 and the cooler 8 to control the temperature of the working medium within a stable range.

[0032] The water heat exchanger 23 is used to cool the coolant to ensure the cooling effect of the coolant on the working medium. The water heat exchanger 23 can be a partition heat exchanger, a spray heat exchanger, a printed circuit board heat exchanger, a jacket heat exchanger or a coil heat exchanger, etc., which are not limited here. In the water heat exchanger 23, the cooling water and the coolant exchange heat to maintain the temperature of the coolant within a stable range.

[0033] A main loop regulating valve 24 may also be provided in the main circulation loop. The main loop regulating valve 24 is provided at the coolant inlet of the cooler 8 to control the coolant flow rate entering the cooler 8. A temperature / density transmitter 25 is provided on the pipeline between the cooler 8 and the compressor 1. The transmitter 25 is used to measure the temperature or density of the working fluid flowing out of the cooler 8. The main loop regulating valve 24 and the transmitter 25 are electrically connected to the control device (not shown). Taking the transmitter 25 for measuring the working fluid temperature as an example, the control device controls the opening of the main loop regulating valve 24 based on the temperature data collected by the transmitter 25.

[0034] The main circuit regulating valve 24 is controlled in the following manner: after receiving data from the transmitter 25, the control device compares the received real-time temperature data with the preset temperature data. When the real-time temperature data reaches the preset temperature data, the control device calculates the opening of the main circuit regulating valve 24 based on the real-time temperature data, and changes or maintains the opening of the main circuit regulating valve 24 based on the calculated result.

[0035] In this embodiment, after the power generation unit is started, the opening of the main circuit regulating valve 24 can be kept at 0 in the initial stage to accumulate heat in the cooler 8. When the working fluid temperature at the outlet of the cooler 8 exceeds T1°C, the main circuit regulating valve is in manual control mode, and the opening is fixed at 5-20%, maintained for at least 1 minute, and then put into automatic control. The control device automatically adjusts the opening of the main circuit regulating valve 24 based on the difference between the measured value of the transmitter 25 and the set value, so as to realize automatic control of the working fluid temperature at the outlet of the cooler 8. T1 can be controlled at around 60, and the lower limit can be set at 45. If it is too low, the heat storage is insufficient and the control is unstable. If the upper limit is too high, the waiting time for heat storage will be long, which may exceed the design temperature of the low-temperature side components of the system.

[0036] The change in the opening of the main loop regulating valve 24 will cause the flow rate of the coolant flowing through the cooler 8 to change. In order to ensure the stability of the total flow rate of the coolant, the circulating pump 21 and the water heat exchanger 23 also constitute a bypass circulation loop of the coolant. A flow meter 22 is provided on the pipeline between the circulating pump 21 and the water heat exchanger 23. The flow meter 22 is used to measure the actual total water volume. A bypass regulating valve 26 is provided on the bypass circulation loop. The bypass regulating valve 26 is used to adjust the coolant flow rate through the bypass circulation to ensure the stability of the total coolant flow rate. The flow meter 22 and the bypass regulating valve 26 are electrically connected to the control device, and the control device controls the opening of the bypass regulating valve 26 based on the flow data collected by the water flow meter 22.

[0037] The bypass regulating valve 26 is controlled in the following manner: after receiving data from the flow meter 22, the control device compares the received real-time flow data with the preset flow data. When the real-time flow data and the preset flow data exceed the set difference, the control device calculates the opening of the bypass regulating valve 26 based on the real-time flow data, and changes or maintains the opening of the bypass regulating valve 26 based on the calculated result.

[0038] Figure 3 This is the temperature change trend diagram of the compressor inlet after the power generation unit is started. Figure 3 It can be seen that after the main circuit regulating valve 24 is started, the compressor inlet temperature can be quickly reduced, and by monitoring the temperature of the working fluid flowing to the cooler 8 and feedback control of the main circuit regulating valve 24, the compressor 1 inlet temperature can be maintained within a stable range, allowing the compressor 1 to operate stably.

[0039] The coolant can also flow through the generator 3, the lubricating oil station 28 matched with the compressor 1, the power conversion control cabinet, etc., so as to realize the cooling of the generator 3, the internal lubricating station 28, and the power conversion control cabinet. Correspondingly, a heat exchanger is arranged in the generator 3, the lubricating oil station 28, and the power conversion control cabinet, and the coolant flows through the generator 3, the lubricating oil station 28, and the heat exchanger in the power conversion control cabinet to reduce the temperature of the generator 3, the lubricating oil station 28, and the power conversion control cabinet. For example, the circulating pump 21, the water heat exchanger 23, and the heat exchanger in the lubricating oil station 28 constitute the cooling branch of the lubricating oil station, and the cooling branch regulating valve 27 is arranged on the cooling branch of the lubricating oil station, and the cooling branch regulating valve 27 is electrically connected to the control device, and the control device controls the opening of the cooling branch regulating valve 27 based on the temperature data of the lubricating oil. The control method of the cooling branch regulating valve 27 can refer to the control method of the main circuit regulating valve 24, and it will not be repeated here to save space.

[0040] The turbine 2 is also called a turbine, an expander, etc. It is a rotary power device. The high-temperature and high-pressure working fluid expands in the turbine 2, converting the thermal energy of the working fluid into mechanical energy, while doing work externally. When the working fluid expands and accelerates in the turbine 2, the pressure and temperature decrease, and the speed increases. The turbine 2 is connected to the regenerator 5 through the pipeline 14. In the pipeline 14, the working fluid flows from the turbine 2 side to the regenerator 5 side.

[0041] The generator 3 refers to a device that converts mechanical energy into electrical energy using the law of electromagnetic induction. The generator 3 can be various forms of synchronous generators, asynchronous generators, single-phase generators, three-phase generators, etc., and is not limited here.

[0042] In this embodiment, CO2 that enables the supercritical carbon dioxide circulation system to operate at full power can be pre-filled in the above pipelines. The regenerator 5 and the heater 6 are used to heat the high-pressure CO2 to obtain high-temperature and high-pressure supercritical carbon dioxide SCO2, and the high-temperature and high-pressure SCO2 is delivered to the turbine 2. The high-temperature and high-pressure SCO2 drives the turbine 2 to rotate, thereby driving the compressor 1 to rotate. The regenerator 5 is also used to pre-cool the SCO2 output from the turbine 2, and deliver the pre-cooled SCO2 to the cooler 8 for cooling. The compressor 1 is used to pressurize the SCO2 cooled by the cooler 8. When the outlet pressure of the compressor 1 is higher than its inlet pressure, the turbine 2 drives the compressor 1 and the generator 3 to rotate simultaneously, so that the generator 3 generates electricity.

[0043] The power generation unit may also include a cooling gas storage tank 7, which is a tank for collecting and storing cooling gas. The cooling gas may be He (helium), the molecular weight of He is much smaller than that of CO2, and the density of He is still relatively low under high pressure, which can effectively reduce the wind wear loss caused by the high pressure in the motor cavity of the generator, so that the generator maintains a high operating efficiency, and can greatly reduce the structural size of the vacuum pump 10, thereby reducing the occupied space of the overall power generation system. In addition, the thermal conductivity of He is more than ten times that of CO2, which is beneficial to improving the cooling efficiency when used for cooling the motor cavity of the generator. Furthermore, the chemical properties of helium are extremely inactive and will not corrode the generator, which can ensure the service life of the generator and the reliability of the system. The cooling gas storage tank 7 is connected to the generator 3 through a pipeline 20, and in the pipeline 20, the cooling gas flows from the cooling gas storage tank 7 side to the generator 3 side.

[0044] Cooling gas can be supplied to the motor cavity of the generator 3 through the cooling gas storage tank 7. The cooling gas exchanges heat with the gas in the motor cavity of the generator 3, which can help control the temperature in the motor cavity of the generator 3, improve the cooling efficiency of the generator 3, and enable the generator 3 to maintain a stable operating temperature under high load conditions, thereby stabilizing the power generation efficiency of the generator 3.

[0045] An air pressure sensor is provided in the motor cavity of the generator 3, and the air pressure sensor is used to measure the air pressure in the motor cavity of the generator 3. The air pressure sensor is electrically connected to a control device (not shown). The control device controls the opening of the cooling gas storage tank outlet regulating valve connected to the pipeline 20 based on the air pressure data collected by the air pressure sensor.

[0046] The air pressure in the motor cavity of the generator 3 is controlled in the following manner: after the control device receives data from the air pressure sensor, it compares the received real-time air pressure data with the preset high air pressure data and low air pressure data. When the real-time air pressure data reaches the preset high air pressure data, the control device calculates the atmosphere pressure in the motor cavity of the generator 3, and calculates the opening of the cooling gas storage tank outlet regulating valve based on the acquired data, and changes or maintains the opening of the cooling gas storage tank outlet regulating valve based on the calculated result. For example, when the atmosphere pressure in the generator 3 cavity is low, the opening value of the cooling gas storage tank outlet regulating valve is set to a large value, and when the atmosphere pressure in the generator 3 cavity is high, the opening value of the cooling gas storage tank outlet regulating valve is set to a large value.

[0047] During the operation of the power generation unit, a small amount of working fluid will leak from the shaft ends of the compressor 1 and the turbine 2. In order to achieve zero leakage of the working fluid to the outside, the working fluid leaking from the shaft ends of the compressor 1 and the turbine 2 can be introduced into the motor cavity of the generator 3 for recovery. In a feasible embodiment, the compressor 1 is connected to the generator 3 through a pipeline 16, and the turbine 2 is connected to the generator 3 through a pipeline 12. In the pipeline 16, the working fluid leaking from the shaft end of the compressor 1 flows from the compressor 1 side to the motor cavity side of the generator 3. In the pipeline 15, the working fluid leaking from the shaft end of the turbine 2 flows from the turbine 2 side to the motor cavity side of the generator 3. Filters can also be set on the pipelines 15 and 16, and the filters are used to filter out bearing lubricating oil and other impurities that may exist in the leaked working fluid.

[0048] It can be understood that the working fluid leaking from the shaft ends of the compressor 1 and the turbine 2, and the cooling gas supplied by the cooling gas storage tank 7 meet in the motor cavity of the generator 3 to form a mixed gas. Since the leaked working fluid flow rate is much smaller than the cooling gas flow rate, the temperature of the cooling gas will not change significantly.

[0049] If the circulating working fluid contains impurities, it will affect the performance of the power generation unit. In order to ensure the efficient operation of the power generation unit, the working fluid must be highly pure. Based on this, the reinjection unit is used to separate the working fluid and cooling gas from the mixed gas, and respectively make the working fluid and cooling gas participate in the fully closed cycle.

[0050] The reinjection unit includes a heat exchanger 4 and at least two adsorption towers 9 .

[0051] The heat exchanger 4 is used to cool the mixed gas. The heat exchanger 4 usually uses water or air as a coolant to remove heat. The heat exchanger 4 can be a partition heat exchanger, a spray heat exchanger, a printed circuit board heat exchanger, a jacket heat exchanger or a coil heat exchanger, etc., which are not limited here. The heat exchanger 4 is connected to the motor cavity of the generator 3 through the pipeline 19. In the pipeline 19, the mixed gas flows from the generator 3 side to the heat exchanger 4 side.

[0052] The adsorption tower 9 is used to separate the working fluid and the cooling gas in the mixed gas. A packed bed is provided in the adsorption tower 9. The packed bed is filled with an adsorbent. The material of the adsorbent is not specifically limited in the embodiment of the present invention. As long as it can adsorb carbon dioxide and does not react chemically with it, and can also desorb carbon dioxide after depressurization, it can be used. For example, the material of the adsorbent is selected from activated carbon, molecular sieve, calcium hydroxide, etc., and one of them can be used, or two or more substances can be used at the same time.

[0053] The adsorption tower 9 is connected with pipelines 111-114, pipeline 111 is a pipeline connecting the heat exchanger 4 and the adsorption tower 9, in which the mixed gas flows from the heat exchanger 4 side to the adsorption tower 9 side, pipeline 112 is a pipeline connecting the two adsorption towers 9, in which the gas flows from one adsorption tower to the other adsorption tower, pipeline 113 is a pipeline connecting the adsorption tower 9 and the cooler 8, in which the working medium flows from the adsorption tower 9 side to the cooler 8 side, pipeline 114 is a pipeline connecting the adsorption tower 9 and the motor cavity of the generator 3, in which the cooling gas flows from the adsorption tower 9 side to the generator 3 side.

[0054] It should be noted that the pipelines mentioned in this embodiment are all provided with control valves.

[0055] The adsorption tower 9 in this embodiment uses a pressure swing adsorption method to treat the mixed gas. Taking two adsorption towers 9 as an example, the cycle sequence of the adsorption process of the two towers is shown in Table 1. Each adsorption tower 9 must go through five process steps of pressurization, adsorption, pressure drop, vacuum, and pressure rise. In order to distinguish, the two adsorption towers 9 are defined as the first adsorption tower and the second adsorption tower, respectively. The adsorption process of the first adsorption tower is as follows:

[0056] Pressurization: Open the valve on the pipeline 111 connecting the first adsorption tower and the heat exchanger 4, and the mixed gas flows from the heat exchanger 4 side to the first adsorption tower side through the pipeline 111;

[0057] Adsorption: After the first adsorption tower completes the pressurization, the mixed gas continues to enter the first adsorption tower, and the CO2 in the mixed gas is adsorbed by the adsorbent. At the same time, the valve on the pipeline 114 is opened, and the cooling gas flows from the first adsorption tower side to the generator 3 side through the pipeline 114;

[0058] Pressure reduction: When the first adsorption tower is saturated with adsorption, close the valve on the pipeline 114 and the valve on the pipeline 111 between the first adsorption tower and the heat exchanger 4, and open the valve on the pipeline 112 to connect the two adsorption towers 9. At this time, the pressure of the first adsorption tower is reduced, and the pressure of the second adsorption tower is increased;

[0059] Vacuuming: After the pressure reduction is completed, the valve on the pipeline 112 is closed, and the valve on the pipeline 113 between the first adsorption tower and the heat exchanger 4 is opened. The first adsorption tower is evacuated by the vacuum pump 10. At this time, the pressure of the first adsorption tower is reduced, the adsorbed CO2 is desorbed from the adsorbent, and the adsorbent is regenerated to prepare for the next adsorption. The desorbed CO2 flows from the first adsorption tower side to the cooler 8 side through the pipeline 113;

[0060] Equalizing the pressure: After vacuuming, close the valve on the pipeline 113 between the first adsorption tower and the heat exchanger 4, open the valve on the pipeline 112, connect the two adsorption towers 9, and use part of the high-pressure gas in the second adsorption tower to increase the pressure of the first adsorption tower.

[0061] Table 1 Cycle timing

[0062]

[0063] It should be noted that the above embodiments can be freely combined as needed. The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A supercritical carbon dioxide cycle power generation system with a water cooling structure, comprising a cooler, a heater, a compressor, a turbine and a generator, wherein the working fluid outlet of the cooler is connected to the working fluid inlet of the compressor through a pipeline, characterized in that: It also includes a circulation pump and a water heat exchanger. The cooler, the circulation pump and the water heat exchanger are connected by a pipeline to form a main circulation loop of the coolant. The main circulation loop is provided with a main circuit regulating valve and a temperature / density transmitter. The main circuit regulating valve is arranged at the coolant inlet of the cooler. The temperature / density transmitter is arranged between the cooler and the compressor. The transmitter and the main circuit regulating valve are electrically connected to the input end and the output end of the control device respectively. The circulation pump and the water heat exchanger also form a bypass circulation loop of the coolant through a pipeline, a bypass regulating valve is provided in the bypass circulation loop, a flow meter is provided on the pipeline between the circulation pump and the water heat exchanger, and the flow meter and the bypass regulating valve are electrically connected to the input end and the output end of the control device respectively; After the internal units of the power generation system are started, the opening of the main circuit regulating valve is initially maintained at 0. When the working medium temperature at the cooler outlet exceeds T1°C, the main circuit regulating valve is in manual control mode, and the opening is fixed at 5-20%, maintained for at least 1 minute, and then put into automatic control. The control device automatically adjusts the opening of the main circuit regulating valve based on the difference between the measured value and the set value of the temperature / density transmitter to control the working medium temperature at the cooler outlet.

2. The supercritical carbon dioxide cycle power generation system with a water cooling structure according to claim 1 is characterized in that: The circulation pump, the water heat exchanger and the heat exchanger in the lubricating oil station are connected through a pipeline and constitute a cooling branch of the lubricating oil station. A cooling branch regulating valve is provided on the cooling branch of the lubricating oil station, and the cooling branch regulating valve is electrically connected to the output end of the control device.

3. The supercritical carbon dioxide cycle power generation system with a water cooling structure according to claim 1, characterized in that: The circulation pump, the water heat exchanger and the heat exchanger in the generator are connected through a pipeline and form a generator cooling branch. The control valve on the generator cooling branch is electrically connected to the output end of the control device.

4. The supercritical carbon dioxide cycle power generation system with a water cooling structure according to claim 1, characterized in that: The circulation pump, the water heat exchanger and the heat exchanger in the power conversion control cabinet are connected through pipelines and constitute a cooling branch of the power conversion control cabinet. The control valve on the cooling branch of the power conversion control cabinet is electrically connected to the output end of the control device.

5. The supercritical carbon dioxide cycle power generation system with a water cooling structure according to claim 1, characterized in that: The main circuit regulating valve is a double valve core regulating valve.

6. The supercritical carbon dioxide cycle power generation system with a water cooling structure according to claim 1, characterized in that: 45≤T1≤60。 7. The supercritical carbon dioxide cycle power generation system with a water cooling structure according to claim 1, characterized in that: The cooler is a microchannel heat exchanger.

8. The supercritical carbon dioxide cycle power generation system with a water cooling structure according to claim 7, characterized in that: The cooler is a printed circuit board heat exchanger.

9. The supercritical carbon dioxide cycle power generation system with a water cooling structure according to claim 1, characterized in that: The cold side fluid of the water heat exchanger is cooling water provided by a natural water source, air or a circulating water system.

10. The supercritical carbon dioxide cycle power generation system with a water cooling structure according to claim 1, characterized in that: The system also includes: a cooling gas storage tank and a reinjection unit, wherein the cooling gas storage tank, the compressor shaft end, and the turbine shaft end are respectively connected to the inlet of the motor cavity through pipelines to form a mixed gas for cooling in the motor cavity, and the cooling gas collected and stored in the cooling gas storage tank is helium; the reinjection unit includes a heat exchanger and at least two adsorption towers, the inlet and outlet of the heat exchanger are respectively connected to the outlet of the motor cavity and the inlet of the adsorption tower through pipelines, the adsorption tower has an adsorbent for separating the working fluid and the cooling gas in the mixed gas, the working fluid outlet of the adsorption tower is connected to the inlet of the cooler through a pipeline, the cooling gas outlet of the adsorption tower is connected to the inlet of the motor cavity through a pipeline, and a vacuum pump is connected to the pipeline between the adsorption tower and the cooler and the pipeline between the adsorption tower and the generator.

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