Complementary energy recovery system and use method thereof

Abstract

The invention relates to the field of chemical production, and discloses a complementary energy recovery system and a use method thereof. The complementary energy recovery system comprises a high-pressure module, an air separation device, a pressurizing part and an expansion machine. The high-pressure module comprises a gas storage device and a first conveying pipeline, and the gas storage device stores high-pressure nitrogen; a waste nitrogen outlet of the air separation device is communicated with the nitrogen using assembly through a second conveying pipeline; the pressurizing part is mounted on the second conveying pipeline, and the pressurizing part pressurizes waste nitrogen in the second conveying pipeline to usable pressure; the expansion machine comprises an expansion section and an output shaft which are connected with each other, the expansion section is installed on the first conveying pipeline, and the output shaft is in driving connection with the pressurizing part. When the pressure of the high-pressure nitrogen is reduced through the expansion machine, the mechanical energy recovered by the expansion machine can drive the pressurizing part to pressurize the waste nitrogen to the usable pressure, and the waste nitrogen can be used in nitrogen using equipment with low nitrogen concentration requirements, so that the energy released when the pressure of the high-pressure nitrogen is reduced is recovered, and the demand quantity of the high-pressure nitrogen is reduced.

Description

Technical Field

[0001] This invention relates to the field of chemical production, specifically to a waste energy recovery system and its usage method. Background Technology

[0002] Nitrogen is a commonly used resource in chemical production. The required purity and pressure of nitrogen vary depending on the application scenario. In actual production processes, the demand for low-pressure nitrogen is relatively large, which may lead to insufficient supply to meet the demand. In such cases, chemical manufacturers will choose to depressurize high-pressure nitrogen to a usable pressure to compensate for the shortage of low-pressure nitrogen. However, depressurizing high-pressure nitrogen releases a significant amount of energy, resulting in substantial energy loss. Summary of the Invention

[0003] The purpose of this invention is to overcome the problem of significant energy loss caused by reducing the pressure of high-pressure nitrogen in chemical equipment before reuse, and to provide a waste energy recovery system and its usage method. The waste energy recovery system includes an air separation unit, a pressurizing component, and an expander. The air separation unit generates a large amount of waste nitrogen during operation. When the high-pressure nitrogen is depressurized by the expander, the mechanical energy recovered by the expander can drive the pressurizing component to pressurize the waste nitrogen to a usable pressure. The pressurized waste nitrogen can then be used in nitrogen-using equipment with lower nitrogen concentration requirements, thereby recovering the energy released during the depressurization of high-pressure nitrogen and reducing the demand for high-pressure nitrogen.

[0004] To achieve the above objectives, the present invention provides a waste energy recovery system for recovering the energy released during the depressurization of high-pressure nitrogen gas through waste nitrogen, the waste energy recovery system comprising:

[0005] A high-pressure module includes a gas storage device and a first delivery pipeline for integrating the gas storage device with nitrogen gas, the gas storage device being used to store the high-pressure nitrogen gas;

[0006] An air separation unit, wherein the waste nitrogen outlet of the air separation unit is connected to the nitrogen usage integration via a second delivery pipeline to deliver waste nitrogen toward the nitrogen usage integration;

[0007] A pressurizing component, installed on the second conveying pipeline, is used to pressurize the polluted nitrogen in the second conveying pipeline to a usable pressure;

[0008] An expander includes an expansion section and an output shaft connected to each other. The expansion section is installed on the first delivery pipe to reduce the pressure of the high-pressure nitrogen gas in the first delivery pipe to the usable pressure. The output shaft is driven to the pressure booster.

[0009] Optionally, the waste energy recovery system further includes a third conveying pipeline and a nitrogen compressor installed on the third conveying pipeline, the third conveying pipeline being connected to the low-pressure nitrogen outlet of the air separation unit and the nitrogen usage unit respectively.

[0010] Optionally, the waste energy recovery system further includes a cooling tower, which includes a heat exchanger. The heat exchanger's working fluid inlet is connected to the outlet of the expansion section, and the heat exchanger's working fluid outlet is connected to the first conveying pipeline to transport the high-pressure nitrogen gas, which has been depressurized to the usable pressure, to the nitrogen gas utilization integration.

[0011] Optionally, the waste nitrogen outlet of the air separation unit is also connected to the cooling tower to deliver a portion of the waste nitrogen into the cooling tower.

[0012] Optionally, the nitrogen usage system includes a waste nitrogen usage section and a pure nitrogen usage section, and the first delivery pipe is used to connect to the waste nitrogen usage section and the pure nitrogen usage section respectively;

[0013] The high-pressure module also includes two solenoid valves installed on the first delivery pipeline, one of which is located near the waste nitrogen usage section, and the other is located near the pure nitrogen usage section.

[0014] Optionally, the booster component is configured as a booster fan, and the rotating shaft of the booster fan is connected to the output shaft.

[0015] Optionally, the waste energy recovery system further includes four shut-off valves, which are respectively located between the expansion section and the nitrogen utilization integration, between the expansion section and the gas storage device, between the pressurization component and the air separation unit, and between the pressurization component and the nitrogen utilization integration.

[0016] This application also proposes a method of using a waste energy recovery system, applied to the waste energy recovery system as described above, the method comprising:

[0017] Obtain the high-pressure nitrogen flow rate in the first conveying pipeline and the waste nitrogen flow rate in the second conveying pipeline;

[0018] Determine whether the high-pressure nitrogen flow rate and the waste nitrogen flow rate meet the requirements of integrated nitrogen usage.

[0019] If not, adjust the flow rates of the first and second delivery pipes respectively.

[0020] Optionally, the step of determining whether the high-pressure nitrogen flow rate and the waste nitrogen flow rate meet the requirements of integrated nitrogen usage specifically includes:

[0021] When the high-pressure nitrogen flow rate is greater than or equal to the pure nitrogen requirement of the nitrogen usage integration, and the waste nitrogen flow rate is greater than or equal to the waste nitrogen requirement of the nitrogen usage integration, then the high-pressure nitrogen flow rate and the waste nitrogen flow rate meet the usage requirements of the nitrogen usage integration.

[0022] Optionally, the nitrogen usage system includes a waste nitrogen usage section and a pure nitrogen usage section, and the first delivery pipe is used to connect to the waste nitrogen usage section and the pure nitrogen usage section respectively;

[0023] After determining whether the waste nitrogen flow rate meets the waste nitrogen demand of the integrated nitrogen usage system, the method further includes:

[0024] When the high-pressure nitrogen flow rate is greater than the pure nitrogen demand of the pure nitrogen usage section, and the sum of the high-pressure nitrogen flow rate and the polluted nitrogen flow rate is greater than the sum of the pure nitrogen demand of the pure nitrogen usage section and the polluted nitrogen demand of the polluted nitrogen usage section, then the high-pressure nitrogen flow rate and the polluted nitrogen flow rate meet the usage requirements of the nitrogen usage integration.

[0025] Through the above technical solution, this application has at least the following beneficial effects:

[0026] (1) During the depressurization of high-pressure nitrogen, the high-pressure module transports the high-pressure nitrogen stored in the gas storage device to the expander through the first conveying channel. As the high-pressure nitrogen passes through the expansion section, the expansion and depressurization of the high-pressure nitrogen causes the expansion section to rotate, and the output shaft, which is integrated with the expansion section, rotates synchronously, thereby driving the pressurizing component to operate. The residual energy recovery system recovers a portion of the energy released during the depressurization of high-pressure nitrogen through the expander in the form of mechanical energy.

[0027] (2) In actual production, the nitrogen concentration requirements for some equipment in the integrated system are not high. Therefore, waste nitrogen can be used instead of low-pressure nitrogen. In the chemical production system where the waste energy recovery system is located, the waste energy recovery system can produce waste nitrogen through the air separation unit, transport the waste nitrogen through the second conveying channel, and pressurize the waste nitrogen to a usable pressure through the pressurizing component. That is, waste nitrogen is produced through the air separation unit and pressurized by recovering the energy released when high-pressure nitrogen is depressurized. The pressurized waste nitrogen can also reduce the demand for high-pressure nitrogen. Therefore, the waste energy recovery system can recover the energy released when high-pressure nitrogen is depressurized through waste nitrogen and reduce the demand for high-pressure nitrogen, thereby further reducing energy loss in the chemical production system. Attached Figure Description

[0028] Figure 1 This is a simplified structural diagram of an embodiment of the waste energy recovery system proposed in this invention;

[0029] Figure 2 This is a flowchart illustrating an embodiment of the waste energy recovery system proposed in this invention.

[0030] Explanation of reference numerals in the attached figures

[0031] 100, Waste Energy Recovery System; 1, High Pressure Module; 11, Gas Storage Device; 12, First Delivery Pipeline; 2, Air Separation Unit; 21, Second Delivery Pipeline; 3, Pressurization Component; 3a, Pressurization Fan; 4, Expander; 5, Cooling Tower; 51, Heat Exchanger; 101, Third Delivery Pipeline; 102, Nitrogen Compressor; 103, Shut-off Valve; 200, Nitrogen Utilization Integration; 210, Pure Nitrogen Utilization Section; 220, Waste Nitrogen Utilization Section. Detailed Implementation

[0032] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0033] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0034] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or implying the number of technical features indicated. Therefore, unless otherwise stated, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; "multiple" means two or more. The term "comprising" and any variations thereof mean non-exclusive inclusion, where one or more other features, integers, steps, operations, units, components, and / or combinations thereof may be present or added.

[0035] In addition, terms such as “center,” “horizontal,” “up,” “down,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer” that indicate orientation or positional relationship are based on the orientation or relative positional relationship shown in the accompanying drawings. They are only for the purpose of simplifying the description of this application and do not indicate that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0036] Furthermore, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0037] Nitrogen is a commonly used resource in chemical production. The required purity and pressure of nitrogen vary depending on the application scenario. In actual production processes, the demand for low-pressure nitrogen is relatively large, which may lead to insufficient supply to meet the demand. In such cases, chemical manufacturers will choose to depressurize high-pressure nitrogen to a usable pressure to compensate for the shortage of low-pressure nitrogen. However, depressurizing high-pressure nitrogen releases a significant amount of energy, resulting in substantial energy loss.

[0038] In the specific application of this application, the waste energy recovery system is used in a coal-to-oil air separation plant. During production, the coal-to-oil air separation plant requires nitrogen at a pressure of 1.0 MPa. However, the amount of low-pressure nitrogen produced by the air separation unit in a conventional coal-to-oil air separation plant is often insufficient to meet the demand. Therefore, the coal-to-oil air separation plant needs to supplement it with high-pressure nitrogen. However, in reality, some equipment in the coal-to-oil air separation plant does not have very high requirements for nitrogen concentration. Therefore, the inventors of this application considered pressurizing the waste nitrogen produced by the air separation unit to 1.0 MPa, thereby reducing the consumption of high-pressure nitrogen and recovering the energy released during the use of high-pressure nitrogen.

[0039] In view of this, this application proposes a waste energy recovery system and its usage method, aiming to solve the problem of huge energy loss in chemical production when high-pressure nitrogen needs to be depressurized for use. Figure 1 This is a simplified structural diagram of an embodiment of the waste energy recovery system proposed in this invention.

[0040] The waste energy recovery system of the present invention will be further illustrated below through embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following embodiments.

[0041] Please see Figure 1The waste energy recovery system 100 proposed in this application is used to recover the energy released during the depressurization of high-pressure nitrogen through waste nitrogen. The waste energy recovery system 100 includes a high-pressure module 1, an air separation unit 2, a pressurizing component 3, and an expander 4. The high-pressure module 1 includes a gas storage device 11 and a first conveying pipe 12 for connecting the gas storage device 11 to a nitrogen utilization integration 200. The gas storage device 11 is used to store the high-pressure nitrogen. The waste nitrogen outlet of the air separation unit 2 is used to connect to the nitrogen utilization integration 200 through a second conveying pipe 21 to deliver waste nitrogen toward the nitrogen utilization integration 200. The pressurizing component 3 is installed on the second conveying pipe 21 and is used to pressurize the waste nitrogen in the second conveying pipe 21 to a usable pressure. The expander 4 includes an expansion section and an output shaft connected to each other. The expansion section is installed on the first conveying pipe 12 and is used to depressurize the high-pressure nitrogen in the first conveying pipe 12 to the usable pressure. The output shaft is drivenly connected to the pressurizing component 3.

[0042] In the technical solution of this application, when high-pressure nitrogen is depressurized, the high-pressure module 1 transports the high-pressure nitrogen stored in the gas storage device 11 to the expander 4 through the first conveying channel. As the high-pressure nitrogen passes through the expansion section, the expansion and depressurization of the high-pressure nitrogen causes the expansion section to rotate, and the output shaft, which is integrated with the expansion section, rotates synchronously, thereby driving the pressure booster 3 to operate. The residual energy recovery system 100 recovers part of the energy released during the depressurization of the high-pressure nitrogen through the expander 4 in the form of mechanical energy.

[0043] In actual production, the nitrogen concentration requirements for some equipment in the integrated system 200 are not high; therefore, waste nitrogen can be used instead of low-pressure nitrogen. In the chemical production system where the waste energy recovery system 100 is located, the system can produce waste nitrogen through the air separation unit 2, transport it through the second conveying channel, and pressurize it to a usable pressure through the pressurizing unit 3. In other words, waste nitrogen is produced through the air separation unit 2 and pressurized by recovering the energy released during the depressurization of high-pressure nitrogen. The pressurized waste nitrogen further reduces the demand for high-pressure nitrogen. Therefore, the waste energy recovery system 100 can recover the energy released during the depressurization of high-pressure nitrogen through waste nitrogen, and also reduce the demand for high-pressure nitrogen, thereby further reducing energy loss in the chemical production system.

[0044] Furthermore, the waste energy recovery system 100 also includes a third conveying pipeline 101 and a nitrogen compressor 102 installed on the third conveying pipeline 101. The third conveying pipeline 101 is used to connect to the low-pressure nitrogen outlet of the air separation unit 2 and the nitrogen usage integration 200, respectively.

[0045] In this embodiment, the waste energy recovery system 100 includes the air separation unit 2, and waste nitrogen is only a byproduct of the air separation unit 2. The air separation unit 2 can also produce high-purity low-pressure nitrogen. The specific pressure value of the low-pressure nitrogen produced by the air separation unit 2 is 0.4 MPa, while the usable pressure required by the nitrogen usage integration 200 in this application is 1.0 MPa. Therefore, the waste energy recovery system 100 also includes the nitrogen compressor 102 installed on the third conveying pipeline 101. The nitrogen compressor 102 can pressurize the low-pressure nitrogen produced by the air separation unit 2 to the usable pressure. The waste energy recovery system 100 pressurizes the high-purity low-pressure nitrogen produced by the air separation unit 2 through the nitrogen compressor 102, directly meeting part of the usage requirements of the nitrogen usage integration 200, reducing the consumption of high-pressure nitrogen, and thus reducing the energy loss that occurs during the depressurization process of high-pressure nitrogen.

[0046] It should be noted that, in this application, the usable pressure of nitrogen is related to the actual chemical production system in which the waste energy recovery system 100 is located. When the chemical production system in which the waste energy recovery system 100 is located is different, the usable pressure of nitrogen will also be different. Therefore, whether the high-purity low-pressure nitrogen produced by the air separation unit 2 is pressurized or depressurized can be adjusted adaptively according to the actual situation, and no specific restrictions are made here.

[0047] In practical applications, when high-pressure nitrogen is depressurized through the expander 4, its temperature decreases synchronously with its pressure. That is, when high-pressure nitrogen is depressurized through the expander 4, some of its energy is lost as cold energy, which is difficult to recover through the expander 4. Therefore, in one embodiment of this application, the waste energy recovery system 100 further includes a cooling tower 5, which includes a heat exchanger 51. The inlet of the heat exchanger 51 is connected to the outlet of the expansion section, and the outlet of the heat exchanger 51 is connected to the first conveying pipeline 12, so as to transport the high-pressure nitrogen depressurized to the usable pressure to the nitrogen utilization integration 200.

[0048] In chemical production, the cooling tower 5 has a significant heat exchange requirement. After the circulating working fluid in the cooling tower 5 exchanges heat with the material, the circulating working fluid needs to be cooled before it can exchange heat again. In the prior art, the cooling tower 5 is generally cooled using conventional cooling equipment such as ice machines. However, in this embodiment, the waste energy recovery system 100 couples the cooling tower 5 with the expansion section, using the cooled high-pressure nitrogen as the cooling working fluid to exchange heat with the circulating working fluid of the cooling tower 5, thereby recovering the cold energy generated when the high-pressure nitrogen is depressurized, further reducing energy loss.

[0049] Please see Figure 1Furthermore, the waste nitrogen outlet of the air separation unit 2 is also connected to the cooling tower 5 to transport a portion of the waste nitrogen into the cooling tower 5. The waste nitrogen can also be used as a cooling working fluid to exchange heat with the circulating working fluid of the cooling tower 5, thereby reducing the cooling tower 5's dependence on cooling equipment and reducing chemical production costs.

[0050] In one embodiment of this application, the nitrogen usage integration 200 includes a waste nitrogen usage section 220 and a pure nitrogen usage section 210. The first delivery pipe 12 is used to connect to the waste nitrogen usage section 220 and the pure nitrogen usage section 210 respectively. The high-pressure module 1 also includes two solenoid valves installed on the first delivery pipe 12. One of the two solenoid valves is set close to the waste nitrogen usage section 220, and the other is set close to the pure nitrogen usage section 210.

[0051] The waste nitrogen utilization section 220 refers to the part of the nitrogen utilization integration 200 that does not require high nitrogen purity. This section can use both waste nitrogen and high-purity nitrogen. The pure nitrogen utilization section 210, on the other hand, refers to the part of the nitrogen utilization integration 200 that requires high nitrogen purity. This section can only use high-purity nitrogen. The first delivery pipe 12 is connected to both the waste nitrogen utilization section 220 and the pure nitrogen utilization section 210, allowing high-pressure nitrogen to be transported to both sections respectively. The first delivery pipe 12 is equipped with solenoid valves corresponding to both sections, ensuring that high-pressure nitrogen prioritizes the pure nitrogen utilization section 210. When waste nitrogen is insufficient for the waste nitrogen utilization section 220, high-pressure nitrogen can compensate for the deficiency, making the waste energy recovery system 100 more adaptable.

[0052] Specifically, the pressurizing component 3 is configured as a pressurizing fan 3a, and the rotating shaft of the pressurizing fan 3a is connected to the output shaft. Since the rotating shaft of the pressurizing fan 3a is connected to the output shaft, the expander 4 can drive the pressurizing fan 3a to rotate via the output shaft, thereby pressurizing the nitrogen. In fact, the pressurizing fan 3a is only one embodiment of the pressurizing component 3. The pressurizing component 3 can also be a centrifugal compressor or a rotary compressor similar to a screw compressor, and the specific embodiment of the pressurizing component 3 can be adjusted according to usage requirements; no additional limitations are imposed here.

[0053] When the waste energy recovery system 100 is operating, various unexpected situations may occur, such as the expander 4 tripping or the compression effect of the booster 3 deviating. In such cases, the waste nitrogen may not be able to be pressurized to the usable pressure, and the high-pressure nitrogen may not be able to be depressurized to the usable pressure. Therefore, in one embodiment of this application, the waste energy recovery system 100 further includes four shut-off valves 103, which are respectively located between the expansion section and the nitrogen utilization integration 200, between the expansion section and the gas storage device 11, between the booster 3 and the air separation device 2, and between the booster 3 and the nitrogen utilization integration 200. When the waste energy recovery system 100 malfunctions, the four shut-off valves 103 can cut off the transport of the first transport pipeline and the second transport pipeline, preventing unusable nitrogen from affecting the nitrogen utilization integration 200.

[0054] Another aspect of this application proposes a method of using the waste energy recovery system 100, applied to the waste energy recovery system 100 as described above. Figure 2 This is a flowchart illustrating an embodiment of the usage method of the waste energy recovery system 100 proposed in this invention. Please refer to [link / reference]. Figure 2 The method of use includes:

[0055] S10, obtain the high-pressure nitrogen flow rate in the first conveying pipe 12 and the waste nitrogen flow rate in the second conveying pipe 21;

[0056] S20, determine whether the high-pressure nitrogen flow rate and the waste nitrogen flow rate meet the requirements of the nitrogen usage integration 200;

[0057] S30, if not, adjust the flow rates of the first conveying pipe 12 and the second conveying pipe 21 respectively.

[0058] In practical application, the waste energy recovery system 100 is equipped with flow meters and regulating valves on the first conveying pipe 12, the second conveying pipe 21, and the third conveying pipe 101. The flow meters sense the gas flow rate in each pipe, and the regulating valves adjust the flow rate. During operation, the system 100 uses flow meters to obtain the high-pressure nitrogen flow rate in the first conveying pipe 12 and the polluted nitrogen flow rate in the second conveying pipe 21, and determines whether these flow rates meet the requirements of the nitrogen utilization integration 200. If the flow rates meet the requirements, the current conveying parameters are maintained; otherwise, the flow rates in the first and second conveying pipes are adjusted to ensure the normal operation of the nitrogen utilization integration 200.

[0059] In some embodiments, step S20 specifically includes:

[0060] When the high-pressure nitrogen flow rate is greater than or equal to the pure nitrogen requirement of the nitrogen usage integration 200, and the waste nitrogen flow rate is greater than or equal to the waste nitrogen requirement of the nitrogen usage integration 200, then the high-pressure nitrogen flow rate and the waste nitrogen flow rate meet the usage requirements of the nitrogen usage integration 200.

[0061] The nitrogen usage integration 200 includes a waste nitrogen usage section 220 that does not require high nitrogen purity and a pure nitrogen usage section 210 that can only use high-purity nitrogen. Therefore, when the high-pressure nitrogen flow rate is greater than or equal to the pure nitrogen demand of the nitrogen usage integration 200 and the waste nitrogen flow rate is greater than or equal to the waste nitrogen demand of the nitrogen usage integration 200, the high-pressure nitrogen flow rate and the waste nitrogen flow rate meet the usage requirements of the nitrogen usage integration 200. At this time, there is no need to adjust the flow rates of the first delivery pipe 12 and the second delivery pipe 21.

[0062] The nitrogen usage integration 200 includes a waste nitrogen usage section 220 and a pure nitrogen usage section 210, and the first delivery pipe 12 is used to connect to the waste nitrogen usage section 220 and the pure nitrogen usage section 210 respectively.

[0063] After determining whether the waste nitrogen flow rate meets the waste nitrogen requirement of the nitrogen usage integration 200, the method further includes:

[0064] When the high-pressure nitrogen flow rate is greater than the pure nitrogen demand of the pure nitrogen usage section 210, and the sum of the high-pressure nitrogen flow rate and the polluted nitrogen flow rate is greater than the sum of the pure nitrogen demand of the pure nitrogen usage section 210 and the polluted nitrogen demand of the polluted nitrogen usage section 220, then the high-pressure nitrogen flow rate and the polluted nitrogen flow rate meet the usage requirements of the nitrogen usage integration 200.

[0065] The first delivery pipe 12 is connected to both the waste nitrogen usage section 220 and the pure nitrogen usage section 210, while the second delivery pipe 21 is only connected to the waste nitrogen usage section 220. In practical applications, the waste nitrogen usage section 220 can use either waste nitrogen or high-purity nitrogen, but the pure nitrogen usage section 210 can only use high-purity nitrogen. Therefore, when the high-pressure nitrogen flow rate is greater than the pure nitrogen requirement of the pure nitrogen usage section 210, it indicates that the requirement of the pure nitrogen usage section 210 can be met. When the sum of the high-pressure nitrogen flow rate and the waste nitrogen flow rate is greater than the sum of the pure nitrogen requirement of the pure nitrogen usage section 210 and the waste nitrogen requirement of the waste nitrogen usage section 220, it indicates that the remaining amount of high-pressure nitrogen after meeting the pure nitrogen requirement of the pure nitrogen usage section 210, along with the waste nitrogen, can jointly meet the requirement of the waste nitrogen usage section 220. In this case, both the high-pressure nitrogen and the waste nitrogen can also meet the usage requirements of the nitrogen usage integration 200.

[0066] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A waste energy recovery system for recovering the energy released during the depressurization of high-pressure nitrogen gas through waste nitrogen, characterized in that, The waste energy recovery system includes: The high-pressure module (1) includes a gas storage device (11) and a first delivery pipe (12) for connecting the gas storage device (11) with a nitrogen gas integration (200), wherein the gas storage device (11) is used to store the high-pressure nitrogen gas. Air separation unit (2), the waste nitrogen outlet of the air separation unit (2) is used to communicate with the nitrogen use integration (200) through a second conveying pipe (21) to convey waste nitrogen toward the nitrogen use integration (200); A pressurizing component (3) is installed on the second conveying pipe (21) to pressurize the polluted nitrogen in the second conveying pipe (21) to a usable pressure; Expander (4) includes an expansion section and an output shaft connected to each other. The expansion section is installed on the first conveying pipe (12) to reduce the pressure of the high-pressure nitrogen in the first conveying pipe (12) to the usable pressure. The output shaft is driven to the booster (3).

2. The waste energy recovery system according to claim 1, characterized in that, The waste energy recovery system (100) also includes a third delivery pipe (101) and a nitrogen compressor (102) installed on the third delivery pipe (101). The third delivery pipe (101) is connected to the low-pressure nitrogen outlet of the air separation unit (2) and the nitrogen usage integration (200), respectively.

3. The waste energy recovery system according to claim 1, characterized in that, The waste energy recovery system (100) further includes a cooling tower (5), which includes a heat exchanger (51). The heat exchanger (51) has a heat exchange medium inlet connected to the outlet of the expansion section and a heat exchange medium outlet connected to the first conveying pipeline (12) to transport the high-pressure nitrogen gas, which has been depressurized to the usable pressure, to the nitrogen gas utilization integration (200).

4. The waste energy recovery system according to claim 3, characterized in that, The waste nitrogen outlet of the air separation unit (2) is also connected to the cooling tower (5) to transport a portion of the waste nitrogen into the cooling tower (5).

5. The waste energy recovery system according to claim 1, characterized in that, The nitrogen usage integration (200) includes a waste nitrogen usage section (220) and a pure nitrogen usage section (210), and the first delivery pipe (12) is used to connect to the waste nitrogen usage section (220) and the pure nitrogen usage section (210) respectively; The high-pressure module (1) also includes two solenoid valves installed on the first delivery pipe (12), one of which is located near the waste nitrogen usage section (220), and the other is located near the pure nitrogen usage section (210).

6. The waste energy recovery system according to claim 1, characterized in that, The booster (3) is configured as a booster fan (3a), and the rotating shaft of the booster fan (3a) is connected to the output shaft.

7. The waste energy recovery system according to claim 1, characterized in that, The waste energy recovery system (100) also includes four shut-off valves (103), which are respectively located between the expansion section and the nitrogen utilization integration (200), between the expansion section and the gas storage device (11), between the pressurizing component (3) and the air separation device (2), and between the pressurizing component (3) and the nitrogen utilization integration (200).

8. A method of using a waste energy recovery system, applied to the waste energy recovery system (100) as described in any one of claims 1 to 7, characterized in that, The method of use includes: Obtain the high-pressure nitrogen flow rate in the first conveying pipe (12) and the waste nitrogen flow rate in the second conveying pipe (21); Determine whether the high-pressure nitrogen flow rate and the waste nitrogen flow rate meet the requirements of the nitrogen usage integration (200); If not, adjust the flow rates of the first conveying pipe (12) and the second conveying pipe (21) respectively.

9. The method of use according to claim 8, characterized in that, The steps for determining whether the high-pressure nitrogen flow rate and the waste nitrogen flow rate meet the requirements of the nitrogen usage integration (200) specifically include: When the high-pressure nitrogen flow rate is greater than or equal to the pure nitrogen requirement of the nitrogen usage integration (200), and the waste nitrogen flow rate is greater than or equal to the waste nitrogen requirement of the nitrogen usage integration (200), then the high-pressure nitrogen flow rate and the waste nitrogen flow rate meet the usage requirements of the nitrogen usage integration (200).

10. The method of use according to claim 9, characterized in that, The nitrogen usage integration (200) includes a waste nitrogen usage section (220) and a pure nitrogen usage section (210), and the first delivery pipe (12) is used to connect to the waste nitrogen usage section (220) and the pure nitrogen usage section (210) respectively; After determining whether the waste nitrogen flow rate meets the waste nitrogen demand of the nitrogen usage integration (200), the method further includes: When the high-pressure nitrogen flow rate is greater than the pure nitrogen demand of the pure nitrogen usage section (210), and the sum of the high-pressure nitrogen flow rate and the polluted nitrogen flow rate is greater than the sum of the pure nitrogen demand of the pure nitrogen usage section (210) and the polluted nitrogen demand of the polluted nitrogen usage section (220), then the high-pressure nitrogen flow rate and the polluted nitrogen flow rate satisfy the use of the nitrogen usage integration (200).

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