A dry gas seal preheating system and method based on motor cooling waste heat utilization

Abstract

The embodiment of the present application provides a kind of based on motor cooling waste heat utilization's dry gas seal preheating system and method, the system includes motor cooling circuit, for cooling to be filled motor;Dry gas seal supply circuit, for providing seal gas to dry gas seal;Intermediate heat exchanger, its hot side is communicated with the motor cooling circuit, its cold side is communicated with the dry gas seal supply circuit;Supplement heat device, it is set on the dry gas seal supply circuit in the downstream direction of intermediate heat exchanger, for heating seal gas.The embodiment of the present application is realized by being arranged between motor cooling circuit and dry gas seal supply circuit intermediate heat exchanger, realizes the transmission and utilization of motor cooling waste heat to dry gas seal supply circuit, while meeting the dry gas seal supply temperature requirement, improve system energy utilization efficiency, reduce the energy consumption of supplement heat device and cooling system heat dissipation load, and avoid extracting high-temperature working medium from main cycle as heat source.

Description

Technical Field

[0001] This invention relates to the field of supercritical carbon dioxide Brayton cycle power generation system technology, and in particular to a dry gas seal preheating system and method based on the utilization of waste heat from motor cooling. Background Technology

[0002] Supercritical carbon dioxide (sCO2) Brayton cycle power generation systems, with their advantages of high efficiency, high power density, and compact structure, have become an important development direction for next-generation power generation technology. In this type of system, rotating machinery such as compressors and turbines typically use dry gas seals for shaft end sealing to ensure system sealing and operational safety.

[0003] The working principle of dry gas seals requires the supply of clean sealing gas at a certain temperature (typically 100 to 120°C) to prevent phase change or icing during the throttling process. Currently, the heating methods for dry gas seal supply mainly include the following two: One method is external electric heating. Part of the carbon dioxide is drawn from the main circulation compressor outlet as sealing gas, heated to the target temperature by an electric heater, and then supplied to the dry gas seal. This method is simple to control, but the electric heater has a high power consumption. Taking a flow rate of 240 Nm³ / h as an example, heating from approximately 50°C to 110°C requires approximately 22 kW of electric heating power, resulting in high energy consumption during long-term operation.

[0004] The second method utilizes the waste heat from the main circulation for heating. For example, the schemes disclosed in patents CN113899096A and CN116498404A involve drawing a high-temperature working fluid (≥150℃) from the hot side of the main circulation regenerator and heating the sealing gas in an independent heat exchanger. Although this method utilizes waste heat, it has the following shortcomings: (1) The heat source is taken from the high-temperature working fluid of the main circulation, and the extraction of heat will affect the thermal efficiency of the main circulation; (2) It requires an independent high-temperature bypass pipeline and heat exchanger, which increases the complexity of the system; (3) It only solves the problem of heating the sealing gas and does not generate a synergistic energy-saving effect with other subsystems. Summary of the Invention

[0005] In view of the above-mentioned problems in the prior art, the present invention provides a dry gas seal preheating system and method based on the utilization of waste heat from motor cooling, so as to solve the technical problems of high energy consumption or system complexity in the prior art.

[0006] This invention provides a dry gas seal preheating system based on the utilization of waste heat from motor cooling, applied to a supercritical carbon dioxide Brayton cycle system, comprising: The motor cooling circuit is used to cool the charging motor; Dry gas seal supply circuit, used to supply sealing gas to the dry gas seal; The intermediate heat exchanger has its hot side connected to the motor cooling circuit and its cold side connected to the dry gas sealing gas supply circuit. The heat exchanger is installed on the dry gas seal supply circuit downstream of the intermediate heat exchanger to heat the seal gas. The cooling medium in the motor cooling circuit absorbs the heat generated by the motor operation and enters the intermediate heat exchanger. It then transfers heat to the sealing gas in the dry gas seal supply circuit through the intermediate heat exchanger, thus preheating the sealing gas. The preheated sealing gas enters the heat replenishment device and is heated to the set temperature. The sealing gas heated to the set temperature is then supplied to the dry gas seal after the flow and pressure are regulated.

[0007] In one embodiment, both the cooling medium in the motor cooling circuit and the sealing gas in the dry gas sealing gas supply circuit are carbon dioxide media.

[0008] In one embodiment, the sealing gas source in the dry gas sealing supply circuit is a portion of the carbon dioxide working fluid drawn from the outlet of the self-circulating compressor.

[0009] In one embodiment, it also includes, The control unit adjusts at least one of the following parameters based on at least one of the following parameters: the outlet temperature of the motor cooling circuit, the preheated temperature of the sealing gas, and the outlet temperature of the heat replenishment device: the flow rate of the motor cooling circuit, the flow rate of the intermediate heat exchanger, and the output power of the heat replenishment device.

[0010] In one embodiment, the flow rate of the intermediate heat exchanger is achieved by adjusting the opening ratio of the bypass valve of the intermediate heat exchanger bypass pipeline, and the bypass pipeline is located between the inlet and outlet of the intermediate heat exchanger.

[0011] In one embodiment, the intermediate heat exchanger employs a counter-current heat exchange method.

[0012] In one embodiment, the intermediate heat exchanger is a plate heat exchanger, a printed circuit board heat exchanger, a microchannel heat exchanger, or a shell-and-tube heat exchanger.

[0013] In one embodiment, the heating device is an electric heater.

[0014] In addition, this invention also provides a dry gas seal preheating method based on the utilization of waste heat from motor cooling, comprising the following steps: Step S1: The cooling medium in the motor cooling circuit absorbs the heat generated by the operation of the pressurized motor in the motor compartment; Step S2: The cooling medium carrying heat enters the intermediate heat exchanger and exchanges heat with the sealing gas in the dry gas sealing supply circuit within the intermediate heat exchanger. Step S3: The sealing gas absorbs the heat from the cooling medium in the motor cooling circuit in the intermediate heat exchanger to complete the preheating. Step S4: The preheated sealing gas enters the heating device and is heated to the set gas supply temperature. Step S5: After the sealing gas is heated to the set temperature, the flow rate and pressure are adjusted and then supplied to the dry gas seal.

[0015] In one embodiment, the cooling medium in the motor cooling circuit and the sealing gas in the dry gas sealing supply circuit are both carbon dioxide media, and the sealing gas in the dry gas sealing supply circuit is a portion of the carbon dioxide working fluid drawn from the outlet of the self-circulating compressor.

[0016] Compared with the prior art, the beneficial effects of the dry gas seal preheating system and method based on the utilization of waste heat from motor cooling provided by the embodiments of the present invention are as follows: (1) The embodiments of the present invention realize the energy cascade utilization between auxiliary systems. By thermally coupling the motor cooling circuit and the dry gas sealing gas supply circuit, the low-grade waste heat originally discharged through the cooler is used to preheat the sealing gas, thereby improving the overall energy utilization efficiency of the system.

[0017] (2) The embodiments of the present invention reduce the load on the heating device. By utilizing the residual heat from the motor cooling to meet part of the sealing gas heating requirement, the amount of heat required by the heating device can be significantly reduced, thereby reducing the system's operating energy consumption.

[0018] (3) The embodiments of the present invention reduce the heat dissipation load of the motor cooling circuit. Before entering the cooler, the motor cooling medium releases some heat to the sealing gas, thereby reducing the heat dissipation load that the cooler needs to bear.

[0019] (4) The embodiments of the present invention do not affect the efficiency of the main cycle. The heat utilized in the embodiments of the present invention comes from the waste heat of the motor cooling circuit, rather than the high-temperature working fluid of the main cycle, and therefore will not affect the thermal efficiency of the supercritical carbon dioxide Brayton cycle main system.

[0020] (5) The embodiments of the present invention realize the coordinated operation of the auxiliary system. By establishing a thermal coupling relationship between the motor cooling circuit and the dry gas seal supply circuit, the coordinated energy utilization between the motor cooling system and the dry gas seal system is realized, thereby improving the overall operating economy of the auxiliary system. Attached Figure Description

[0021] Figure 1 A schematic diagram of a dry gas seal preheating system based on the utilization of waste heat from motor cooling, provided in an embodiment of the present invention; Figure 2 This is a flowchart of a prior art supercritical carbon dioxide Brayton cycle dry gas sealed gas supply system according to an embodiment of the present invention; Figure 3This is a schematic diagram of the process of a supercritical carbon dioxide Brayton cycle dry gas seal preheating system, which is based on the utilization of waste heat from motor cooling, as provided in an embodiment of the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Various embodiments and features of this application are described herein with reference to the accompanying drawings.

[0024] These and other features of this application will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.

[0025] It should also be understood that although this application has been described with reference to some specific examples, those skilled in the art can certainly implement many other equivalent forms of this application, which have the features described in the claims and are therefore all within the scope of protection defined herein.

[0026] The above and other aspects, features and advantages of this application will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.

[0027] Specific embodiments of this application are described below with reference to the accompanying drawings; however, it should be understood that the claimed embodiments are merely examples of this application, which can be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to ascertain the true intent based on the user's historical operations, and to avoid unnecessary or redundant details that would obscure this application. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but merely serve as the basis and representative basis for the claims to teach those skilled in the art to use this application in various ways with substantially any suitable detailed structure.

[0028] This specification may use the phrases “in one embodiment,” “in another embodiment,” “in yet another embodiment,” or “in other embodiments,” all of which may refer to one or more of the same or different embodiments according to this application.

[0029] Based on the background information, the applicant has found that in a Brayton cycle CO2 power generation system, the charging motor typically operates in a CO2 environment of 0.3–1.5 MPa, generating continuous heat due to rotor aerodynamic losses, bearing losses, and electromagnetic losses. To ensure safe motor operation, an independent closed-loop cooling circuit is usually installed, utilizing CO2 as a cooling medium to remove the heat. Taking a 200kW charging motor as an example, the temperature of the CO2 cooling medium at the motor cooling circuit outlet can typically reach 70–100°C, possessing high recyclability. In existing technologies, this heat is generally directly discharged into the environment via a cooler, representing a low-grade waste heat resource that has not yet been effectively utilized. Patent CN118548126A discloses a supercritical CO2 circulation system integrating cooling and leakage reinjection, which integrates the motor cooling circuit with a leakage gas recovery circuit to achieve the recovery and utilization of the cooling medium and leakage gas. This solution mainly addresses the issues of cooling medium recovery and leakage gas reinjection, but does not involve using the waste heat from the motor cooling circuit to preheat the dry gas seal supply, nor does it address the thermal coupling between the motor cooling circuit and the dry gas seal supply system.

[0030] Further analysis revealed a good match between the temperature range of the low-grade heat discharged from the pressurizing motor cooling circuit and the preheating requirements of the dry gas sealing supply. If the motor cooling circuit and the dry gas sealing supply circuit could be thermally coupled, the low-grade waste heat originally discharged through the cooler could be used to preheat the sealing gas, thereby reducing the need for additional heat to the sealing gas. Simultaneously, since the heat transfer is completed within the auxiliary system, there is no need to extract the high-temperature working fluid from the main circulation as a heat source, thus not affecting the thermal efficiency of the supercritical carbon dioxide Brayton cycle main system.

[0031] Therefore, how to achieve energy coupling and utilization between the pressurized motor cooling circuit and the dry gas sealing gas supply circuit without affecting the main cycle efficiency and motor cooling performance, fully recover the originally emitted low-grade waste heat, and reduce the energy consumption of sealing gas heating has become a technical problem that urgently needs to be solved in the embodiments of the present invention.

[0032] The principles and features of the present invention are described below with reference to the accompanying drawings. The embodiments described are for illustrative purposes only and are not intended to limit the scope of the invention. The following description, in conjunction with... Figure 1 The preferred embodiments of the present invention will be described in further detail below: This invention provides an embodiment of the invention that, by setting an intermediate heat exchanger between the motor cooling circuit and the dry gas seal supply circuit, enables the transfer and utilization of the motor cooling waste heat to the dry gas seal supply circuit. This not only meets the dry gas seal supply temperature requirements but also improves the system's energy efficiency, reduces the energy consumption of the supplementary heating device and the heat dissipation load of the cooling system, and avoids extracting high-temperature working fluid from the main circulation as a heat source.

[0033] like Figure 1As shown, this embodiment of the invention provides a dry gas seal preheating system based on the utilization of waste heat from motor cooling, applied to a supercritical carbon dioxide Brayton cycle system, comprising: The motor cooling circuit (rotor cooling gas circuit) is used to cool the motor. The motor is a pressurized motor, and its internal pressurizing medium is carbon dioxide with a pressurizing pressure of 0.3 to 1.5 MPa. The wind friction loss, electromagnetic loss and bearing loss generated during the operation of the motor are carried away by the cooling medium of the motor cooling circuit. Dry gas seal supply circuit, used to supply sealing gas to the dry gas seal; The intermediate heat exchanger has its hot side connected to the motor cooling circuit and its cold side connected to the dry gas sealing gas supply circuit. The heat exchanger is installed on the dry gas seal supply circuit downstream of the intermediate heat exchanger to heat the seal gas. The cooling medium in the motor cooling circuit absorbs the heat generated by the motor operation and enters the intermediate heat exchanger. It then transfers heat to the sealing gas in the dry gas seal supply circuit through the intermediate heat exchanger, thus preheating the sealing gas. The preheated sealing gas enters the heat replenishment device and is heated to the set temperature. The sealing gas heated to the set temperature is then supplied to the dry gas seal after the flow and pressure are regulated.

[0034] In one embodiment, the supercritical carbon dioxide Brayton cycle system includes a main cycle compressor, a regenerator, a heat source, a turbine, and a main cooler.

[0035] In one embodiment, the motor cooling circuit is a closed-loop circuit, including a motor cooling chamber, a rotor cooling gas compressor, a pressurizing motor, and a rotor cooling gas cooler. The rotor cooling gas is pressurized by the rotor cooling gas compressor and then enters the pressurizing motor to absorb heat. After releasing heat through an intermediate heat exchanger, it enters the rotor cooling gas cooler for cooling and returns to the rotor cooling gas compressor to form a cycle.

[0036] In one embodiment, the sealing gas source in the dry gas sealing supply circuit is a portion of the carbon dioxide working fluid drawn from the outlet of the self-circulating compressor.

[0037] In one embodiment, the dry gas sealing gas supply circuit includes an intermediate heat exchanger, a heat replenishment device, and a flow and pressure regulating unit; the sealing gas is preheated by the intermediate heat exchanger and then enters the heat replenishment device for heat replenishment, and is then supplied to the dry gas seal after being regulated by the flow and pressure regulating unit.

[0038] In one embodiment, it also includes, The control unit adjusts at least one of the following parameters based on at least one of the following parameters: the outlet temperature of the motor cooling circuit, the preheated temperature of the sealing gas, and the outlet temperature of the heat replenishment device: the flow rate of the motor cooling circuit, the flow rate of the intermediate heat exchanger, and the output power of the heat replenishment device.

[0039] In one embodiment, the flow rate of the intermediate heat exchanger is achieved by adjusting the opening ratio of the bypass valve of the intermediate heat exchanger bypass pipeline, and the bypass pipeline is located between the inlet and outlet of the intermediate heat exchanger.

[0040] In one embodiment, the intermediate heat exchanger employs a counter-current heat exchange method.

[0041] In one embodiment, the intermediate heat exchanger is a plate heat exchanger, a printed circuit board heat exchanger (PCHE), a microchannel heat exchanger, or a shell-and-tube heat exchanger.

[0042] In one embodiment, the heating device is an electric heater.

[0043] In addition, this invention also provides a dry gas seal preheating method based on the utilization of waste heat from motor cooling, comprising the following steps: Step S1: The cooling medium in the motor cooling circuit absorbs the heat generated by the operation of the pressurized motor in the motor compartment; Step S2: The cooling medium carrying heat enters the intermediate heat exchanger and exchanges heat with the sealing gas in the dry gas sealing supply circuit within the intermediate heat exchanger. Step S3: The sealing gas absorbs the heat from the cooling medium in the motor cooling circuit in the intermediate heat exchanger to complete the preheating. Step S4: The preheated sealing gas enters the heating device and is heated to the set gas supply temperature. Step S5: After the sealing gas is heated to the set temperature, the flow rate and pressure are adjusted and then supplied to the dry gas seal.

[0044] This invention utilizes the low-grade waste heat discharged from the cooling circuit of the pressurized motor as a preheating heat source for the dry gas seal supply, achieving thermal coupling between the motor cooling system and the dry gas seal supply system. Because the outlet temperature range of the motor cooling circuit and the preheating temperature range required for the dry gas seal supply have a good matching relationship, the overall energy utilization efficiency of the system can be improved without affecting the motor cooling performance and the thermal efficiency of the main cycle.

[0045] Example 1 like Figure 3As shown, this embodiment provides a dry gas seal preheating system based on the utilization of waste heat from motor cooling, which is applied to a supercritical carbon dioxide Brayton cycle power generation system. The supercritical carbon dioxide Brayton cycle power generation system includes a main cycle compressor, a regenerator, a heat source, a turbine, a main cooler, a pressurized motor, a rotor cooling gas compressor, a rotor cooling gas cooler, an electric heater (heat supplement device), a flow and pressure regulating unit, a leakage recovery and chamber pressure control unit, and an intermediate heat exchanger. The main cycle compressor, regenerator, heat source, turbine, and main cooler constitute the main cycle of the supercritical carbon dioxide Brayton cycle. The working fluid in the main cycle is cooled by the main cooler and then enters the main cycle compressor for compression. The compressed high-pressure working fluid is heated by the regenerator and heat source before entering the turbine for expansion and work. After recovering waste heat through the regenerator, it re-enters the main cooler, thus forming a closed supercritical carbon dioxide cycle.

[0046] The turbine and the main circulation compressor are connected via a charging motor to form a coaxial power unit. The charging motor is filled with carbon dioxide gas, and the internal charging pressure is preferably 0.3–1.5 MPa. During operation, the wind friction loss, bearing friction loss, and electromagnetic loss generated by the charging motor are converted into heat, which is carried away by the rotor cooling gas (cooling medium). The rotor cooling gas compressor drives the circulation of the rotor cooling gas. After being pressurized by the rotor cooling gas compressor, the rotor cooling gas enters the charging motor to absorb heat, forming high-temperature rotor cooling gas. In this embodiment, the temperature of the rotor cooling gas before entering the charging motor is approximately 35°C, and the temperature rises to approximately 84.7°C after leaving the charging motor.

[0047] Figure 2 As a prior art, and Figure 2 Unlike existing technologies, this invention adds an intermediate heat exchanger between the rotor cooling gas circuit (motor cooling circuit) and the dry gas sealing supply circuit. The hot side of the intermediate heat exchanger is connected to the rotor cooling gas circuit, and its cold side is connected to the dry gas sealing supply circuit, enabling the transfer of waste heat from motor cooling to the sealing gas circuit. A portion of high-pressure carbon dioxide is drawn from the main cycle compressor outlet as the sealing gas source. This sealing gas has a temperature of approximately 50°C and a pressure of approximately 14 MPa. The sealing gas first enters the intermediate heat exchanger, where it exchanges heat with the high-temperature rotor cooling gas from the pressurized motor. During the heat exchange, the rotor cooling gas releases heat, and the sealing gas absorbs heat. After preheating by the intermediate heat exchanger, the sealing gas temperature rises from approximately 50°C to approximately 66.7°C. Simultaneously, the rotor cooling gas temperature decreases from approximately 84.7°C to approximately 55.1°C. The cooled rotor cooling gas then enters a rotor cooling gas cooler for further cooling before returning to the rotor cooling gas compressor, thus forming a closed-loop cooling cycle.

[0048] The preheated sealing gas enters the electric heater for reheating. The electric heater further heats the sealing gas to approximately 110°C. The sealing gas then enters the flow and pressure regulation unit, which adjusts the supply pressure and flow rate. The regulated sealing gas is then supplied to the dry gas seals of the main circulation compressor and the turbine. Leakage gas generated during the dry gas seal operation enters the leakage recovery and chamber pressure control unit. The leakage recovery and chamber pressure control unit is used to recover carbon dioxide gas leaking from the dry gas seal and maintain stable internal pressure in the pressurizing motor.

[0049] Through the above structure, the embodiments of the present invention realize the thermal coupling between the rotor cooling gas circuit and the dry gas sealing gas supply circuit, so that part of the low-grade waste heat originally discharged through the rotor cooling gas cooler is used for sealing gas preheating.

[0050] use Figure 2 Calculations are performed based on the existing technical solution shown. The outlet sealing gas temperature of the main circulation compressor is approximately 50℃, the pressure is approximately 14MPa, and the flow rate is approximately 240Nm³ / h. The sealing gas directly enters the electric heater and is heated to 110℃ before being supplied to the dry gas seal. Under this operating condition, the heating power required by the electric heater is approximately 22.22kW. In the rotor cooling gas circuit, the rotor cooling gas is heated from 35℃ to 84.7℃ before directly entering the rotor cooling gas cooler. The cooling load borne by the rotor cooling gas cooler is approximately 13.43kW.

[0051] use Figure 3 The calculations are performed according to the embodiment of the present invention shown. The sealing gas from the main circulation compressor outlet first enters the intermediate heat exchanger. The rotor cooling gas and the sealing gas exchange heat counter-currently within the intermediate heat exchanger. The sealing gas temperature increases from 50°C to 66.7°C. The rotor cooling gas temperature decreases from 84.7°C to 55.1°C. The intermediate heat exchanger recovers approximately 8.06 kW of heat. After preheating, the sealing gas enters the electric heater and only needs to be further heated to 110°C to meet the dry gas sealing supply requirements. At this point, the power required by the electric heater is approximately 14.16 kW. Compared with the prior art, the power of the electric heater is reduced by approximately 36%. Simultaneously, because some heat is recovered and utilized through the intermediate heat exchanger, the cooling load borne by the rotor cooling gas cooler is reduced to approximately 5.37 kW, a reduction of approximately 60% compared to the prior art.

[0052] Table 1. Performance Comparison of Embodiments of the Invention with Existing Technologies (Comparison under Typical Operating Conditions)

[0053] The results show that the embodiments of the present invention can effectively utilize the low-grade waste heat in the pressurized motor cooling system to achieve energy coupling between the motor cooling circuit and the dry gas sealing gas supply circuit. Under the premise of not affecting the main circulation operation and the dry gas sealing gas supply requirements, the supplementary heat energy consumption and cooling load are significantly reduced, and the overall energy utilization efficiency of the system is improved.

[0054] Through the above embodiments, the present invention realizes the cascade utilization of low-grade waste heat between auxiliary systems, improves the system energy utilization efficiency, and meets the dry gas sealing supply temperature requirements without affecting the main circulation operation.

[0055] Industrial applicability The dry gas seal preheating system and method based on the utilization of motor cooling waste heat provided in this invention embodiment realizes the transfer and utilization of motor cooling waste heat to the dry gas seal supply circuit by setting an intermediate heat exchanger between the motor cooling circuit and the dry gas seal supply circuit, thereby improving the system's energy utilization efficiency and reducing the energy consumption of the supplementary heating device and the heat dissipation load of the cooling system.

[0056] The embodiments of the present invention can be applied to supercritical carbon dioxide Brayton cycle power generation systems, shipboard supercritical carbon dioxide power systems, land-based supercritical carbon dioxide power generation devices, nuclear waste heat utilization systems, solar thermal power generation systems, and industrial waste heat recovery power generation systems, and are particularly suitable for closed-cycle power systems that employ pressurized motors and dry gas sealed structures.

[0057] This invention fully utilizes the low-grade waste heat in the motor cooling system to achieve energy cascade utilization between auxiliary systems. Without affecting the main circulation operation and dry gas sealing supply requirements, it effectively reduces system operating energy consumption and improves the overall energy utilization efficiency of the system, demonstrating good engineering application value and promotion prospects.

[0058] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.

Claims

1. A dry gas seal preheating system based on the utilization of waste heat from motor cooling, applied to a supercritical carbon dioxide Brayton cycle system, characterized in that, include: The motor cooling circuit is used to cool the charging motor; Dry gas seal supply circuit, used to supply sealing gas to the dry gas seal; The intermediate heat exchanger has its hot side connected to the motor cooling circuit and its cold side connected to the dry gas sealing gas supply circuit. The heat exchanger is installed on the dry gas seal supply circuit downstream of the intermediate heat exchanger to heat the seal gas. The cooling medium in the motor cooling circuit absorbs the heat generated by the motor operation and enters the intermediate heat exchanger. It then transfers heat to the sealing gas in the dry gas seal supply circuit through the intermediate heat exchanger, thus preheating the sealing gas. The preheated sealing gas enters the heat replenishment device and is heated to the set temperature. The sealing gas heated to the set temperature is then supplied to the dry gas seal after the flow and pressure are regulated.

2. The dry gas seal preheating system based on the utilization of waste heat from motor cooling according to claim 1, characterized in that: The cooling medium in the motor cooling circuit and the sealing gas in the dry gas sealing gas supply circuit are both carbon dioxide media.

3. The dry gas seal preheating system based on the utilization of waste heat from motor cooling according to claim 2, characterized in that: The sealed gas source in the dry gas sealed gas supply circuit is a portion of the carbon dioxide working fluid drawn from the outlet of the self-circulating compressor.

4. The dry gas seal preheating system based on the utilization of waste heat from motor cooling according to claim 1, characterized in that: It also includes, The control unit adjusts at least one of the following parameters based on at least one of the following parameters: the outlet temperature of the motor cooling circuit, the preheated temperature of the sealing gas, and the outlet temperature of the heat replenishment device: the flow rate of the motor cooling circuit, the flow rate of the intermediate heat exchanger, and the output power of the heat replenishment device.

5. A dry gas seal preheating system based on the utilization of waste heat from motor cooling according to claim 4, characterized in that: The flow rate of the intermediate heat exchanger is achieved by adjusting the opening ratio of the bypass valve in the intermediate heat exchanger bypass pipeline, which is located between the inlet and outlet of the intermediate heat exchanger.

6. The dry gas seal preheating system based on the utilization of waste heat from motor cooling according to claim 1, characterized in that: The intermediate heat exchanger adopts a counter-current heat exchange method.

7. A dry gas seal preheating system based on the utilization of waste heat from motor cooling according to claim 6, characterized in that: The intermediate heat exchanger is a plate heat exchanger, a printed circuit board heat exchanger, a microchannel heat exchanger, or a shell-and-tube heat exchanger.

8. A dry gas seal preheating system based on the utilization of waste heat from motor cooling according to claim 1, characterized in that: The heating device is an electric heater.

9. A dry gas seal preheating method based on the utilization of waste heat from motor cooling, characterized in that, Includes the following steps: Step S1: The cooling medium in the motor cooling circuit absorbs the heat generated by the operation of the pressurized motor in the motor compartment; Step S2: The cooling medium carrying heat enters the intermediate heat exchanger and exchanges heat with the sealing gas in the dry gas sealing supply circuit within the intermediate heat exchanger. Step S3: The sealing gas absorbs the heat from the cooling medium in the motor cooling circuit in the intermediate heat exchanger to complete the preheating. Step S4: The preheated sealing gas enters the heating device and is heated to the set gas supply temperature. Step S5: After the sealing gas is heated to the set temperature, the flow rate and pressure are adjusted and then supplied to the dry gas seal.

10. A dry gas seal preheating method based on the utilization of waste heat from motor cooling, as described in claim 9, characterized in that: The cooling medium in the motor cooling circuit and the sealing gas in the dry gas sealing supply circuit are both carbon dioxide media. The sealing gas in the dry gas sealing supply circuit is a portion of the carbon dioxide working fluid drawn from the outlet of the self-circulating compressor.

Images