Natural gas compressor outlet waste heat recovery system and recovery method

Abstract

The invention discloses a natural gas compressor outlet waste heat recovery system and method.The recovery system comprises a water pump, a circulating water tank, a heat exchanger and a phase change heat reservoir set, the circulating water tank is located at the outlet end of the water pump, and the heat exchanger is located at the outlet end of the circulating water tank; the phase change heat storage device sets are located at the outlet end of the heat exchanger, the number of the phase change heat storage device sets is one or more, each phase change heat storage device set comprises two phase change heat storage devices connected in parallel, and the water pump is located at the outlet end of the phase change heat storage device set to form a waste heat recovery circulation path. The parallel phase change heat storage devices are arranged, so that the heat storage process and the heat release process are independently carried out, mutual interference is avoided, heat storage and heat release are carried out at the same time, and the heat storage efficiency and the heat release efficiency are improved.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery and utilization technology at the outlet of natural gas compressors in natural gas compressor stations, specifically to a waste heat recovery system and method for natural gas compressor outlets. Background Technology

[0002] Natural gas, as a clean and efficient energy source, has been widely used globally in recent years. With the increasing demand for natural gas, natural gas compressors, as key equipment for transporting natural gas, are also increasingly widely used. During the natural gas compression process, the temperature of the natural gas at the compressor outlet is relatively high, and this heat is usually directly released into the environment, resulting in significant energy waste. Based on the needs of energy conservation and efficiency improvement, recovering and utilizing the waste heat from the natural gas compressor outlet has become an important technical approach to improve the overall energy efficiency of the system, reduce energy consumption, and decrease carbon emissions.

[0003] Currently, some waste heat recovery systems exist on the market. These systems primarily rely on heat exchangers to exchange heat with the high-temperature gas exiting the compressor, and then utilize the recovered heat to supply other equipment or for heat storage. However, existing technologies suffer from low heat storage efficiency. The heat recovery and heat release processes in existing heat storage systems interfere with each other, resulting in low heat storage efficiency, which in turn affects heat release efficiency.

[0004] Therefore, this patent application is filed. Summary of the Invention

[0005] The purpose of this invention is to provide a natural gas compressor outlet waste heat recovery system, which solves the problem of low heat storage and heat release efficiency in current natural gas compressor outlet waste heat recovery systems.

[0006] The first objective of this invention is to provide a natural gas compressor outlet waste heat recovery system, which employs the following technical solution:

[0007] The system includes a water pump, a circulating water tank, a heat exchanger, and a phase change thermal storage unit (PCS) assembly. The circulating water tank is located at the outlet end of the water pump, the heat exchanger is located at the outlet end of the circulating water tank, and the PCS assembly is located at the outlet end of the heat exchanger. There are one or more PCS assemblies, and each PCS assembly includes two PCS assemblies connected in parallel. The water pump is located at the outlet end of the PCS assembly, forming a waste heat recovery circulation path.

[0008] In an optional embodiment, a flow meter is provided on the connecting pipe between the circulating water tank and the heat exchanger, and the heat exchanger is provided with a natural gas heat exchange inflow pipe and a natural gas heat exchange outflow pipe.

[0009] In an optional embodiment, a solenoid valve V1, a temperature sensor T1, and a pressure sensor A are sequentially installed on the connecting pipe between the flow meter and the heat exchanger. A branch pipe is provided at the rear end of the pressure sensor A. Solenoid valves V2 and V3 are respectively installed on the connecting pipes between the branch pipe and the natural gas heat exchange inflow pipe and the natural gas heat exchange outflow pipe.

[0010] In an optional embodiment, a temperature sensor T2 and a solenoid valve V4 are provided on the connecting pipe between the natural gas heat exchange inflow pipe and the heat exchanger, and a temperature sensor T3 and a solenoid valve V5 are provided on the connecting pipe between the natural gas heat exchange outflow pipe and the heat exchanger.

[0011] In an optional embodiment, a solenoid valve V6, a temperature sensor T3, and a pressure sensor B are provided on the connecting pipeline between the heat exchanger and the phase change thermal storage unit group. Solenoid valves, pressure sensors, and temperature and pressure sensors B are provided at the front and rear ends of the two phase change thermal storage units in each phase change thermal storage unit group.

[0012] In an optional embodiment, a valve is provided on the connecting pipe between the temperature sensor and pressure sensor B at the rear end of each phase change thermal storage unit.

[0013] In an optional embodiment, the phase change thermal energy storage device is connected to a domestic hot water inlet pipe at its inlet end and a domestic hot water outlet pipe at its outlet end to provide heat to users, and corresponding valves are installed on the connecting pipes.

[0014] In an optional embodiment, an absorption chiller is also included for using heat from the phase change heat storage unit to drive refrigeration to generate cooling capacity.

[0015] In an optional embodiment, the absorption chiller unit is a single-effect lithium bromide absorption chiller unit that can operate at temperatures above 80°C. The absorption chiller unit is equipped with a chilled water inlet pipe 83, a chilled water outlet pipe 84, a cooling water inlet pipe 85, and a cooling water outlet pipe 86. One end of the absorption chiller unit is connected to the inlet end of the phase change heat storage unit, and the other end is connected to the outlet end of the phase change heat storage unit. Corresponding valves are provided on the connecting pipes.

[0016] It also includes a controller, which is connected to each solenoid valve, valve, sensor, and water pump.

[0017] The second objective of this invention is to provide a method for recovering waste heat from the outlet of a natural gas compressor, employing the following technical solution:

[0018] The process includes the following:

[0019] When the natural gas compressor is running, the circulating water pump works, and the heat transfer fluid enters the heat exchanger through the circulating water tank, where it exchanges heat with the natural gas and its temperature rises.

[0020] After the temperature rises, the heat transfer fluid flows into the phase change heat storage unit for heat storage, and after the temperature drops, the heat transfer fluid returns to the circulating water tank via the circulating water pump to enter the next cycle.

[0021] The heat storage and release processes of the two phase change thermal storage devices in each group are carried out alternately.

[0022] During heat storage, the heat transfer fluid flows into a phase change heat storage device to store the heat;

[0023] When releasing heat, the low-temperature heat transfer fluid enters another phase change heat storage device and absorbs heat. The heat transfer fluid with the increased temperature then supplies heat to users through the domestic hot water inlet pipe and the domestic hot water outlet pipe. Alternatively, the heat transfer fluid with the increased temperature can be passed into an absorption chiller unit, and the heat in the other phase change heat storage device can be used to drive refrigeration to generate cooling capacity.

[0024] In an optional embodiment, the controller collects monitoring data from the corresponding sensors to determine whether it is necessary to switch the operating state of two phase change thermal storage devices in each group of phase change thermal storage devices. If a switch is required, the controller controls the opening and closing of the corresponding valves to switch the phase change thermal storage device to the heat storage or heat release state. If a switch is not required, the system continues to operate.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] In this invention, one or more phase change thermal energy storage units are set up. Each phase change thermal energy storage unit consists of two phase change thermal energy storage units, which realizes the large-scale storage and stable release of heat. The two phase change thermal energy storage units are set up in parallel, so one can store heat and the other can release heat. The heat storage and heat release processes can be carried out independently without interfering with each other. Heat storage and heat release are carried out simultaneously, which improves the efficiency of heat storage and heat release. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0028] Figure 1 This is a schematic diagram of the waste heat recovery system provided by the present invention.

[0029] Figure 2 This is a schematic diagram illustrating the state switching control principle of two phase change thermal storage devices in each group of phase change thermal storage devices in this invention.

[0030] In the picture:

[0031] 1-PC host; 2-Water pump; 31-Temperature sensor T1; 32-Temperature sensor T2; 33-Temperature sensor T3; 34-Temperature sensor T4; 35-Temperature sensor T5; 36-Temperature sensor T6; 4-Natural gas heat exchanger outflow pipe; 5-Natural gas heat exchanger inflow pipe; 6-Heat exchanger; 71-Solenoid valve V6; 72-Valve H; 73-Solenoid valve V8; 712-Solenoid valve V9; 74-Solenoid valve V10; 75-Valve G; 76-Solenoid valve V3; 77-Solenoid valve V2; 78-Solenoid valve V4; 79-Valve E; 710-Valve F; 711-Solenoid valve V 7, 712 - Solenoid valve V9; 713 - Valve B; 714 - Valve A; 715 - Valve C; 716 - Valve D; 717 - Solenoid valve V5; 718 - Solenoid valve V1; 81 - Domestic hot water inlet pipe; 82 - Domestic hot water inlet pipe; 83 - Chilled water inlet pipe; 84 - Chilled water outlet pipe; 85 - Cooling water inlet pipe; 86 - Cooling water outlet pipe; 91 - Phase change thermal storage unit A; 92 - Phase change thermal storage unit B; 10-11 - Flow meter; 12 - Circulating water tank; 131 - Pressure sensor A; 132 - Pressure sensor B; 133 - Pressure sensor C; 14 - Branch pipe. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0034] In the description of the embodiments of this application, the terms "center", "upper", "lower", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inner", "outer", "front", "rear", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this application and to simplify the description, and are not intended to indicate or imply that the device or component 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.

[0035] In the description of this invention, unless otherwise explicitly specified and limited, the terms "set up," "have," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] like Figure 1 As shown, a natural gas compressor outlet waste heat recovery system includes a water pump 2, a circulating water tank 12, a heat exchanger 6, and a phase change thermal storage (PCS) unit group. The circulating water tank 12 is located at the outlet end of the water pump 2, the heat exchanger 6 is located at the outlet end of the circulating water tank 12, and the PCS unit group is located at the outlet end of the heat exchanger 6. One or more PCS units are provided, and each PCS unit group includes two PCS units connected in parallel. The water pump 2 is located at the outlet end of the PCS unit group, forming a waste heat recovery circulation path. The heat transfer fluid enters the circulating water tank 12 via the water pump 2. After entering the heat exchanger 6, it exchanges heat with the natural gas in the heat exchanger 6, causing its temperature to rise. The increased temperature of the heat transfer fluid then flows through the PCS unit group, transferring heat to the PCS units for storage and causing its temperature to drop. Finally, it returns to the circulating water tank 12 via pipes and the circulating water pump 2 to begin the next cycle. The water pump 2, circulating water tank 12, heat exchanger 6, and phase change heat storage unit together form a heat exchange circulation system. The heat is transferred to the heat transfer fluid through the indirect heat exchanger 6, and then the heat transfer fluid transfers the heat to the phase change heat storage unit for heat storage.

[0037] In this embodiment, one or more phase change thermal energy storage units are set up. Each phase change thermal energy storage unit consists of two phase change thermal energy storage units, which realizes the large-scale storage and stable release of heat. The two phase change thermal energy storage units are set up in parallel, so one can store heat and the other can release heat. The heat storage and heat release processes can be carried out independently without interfering with each other. Heat storage and heat release can be carried out simultaneously, thereby improving the efficiency of heat storage and heat release.

[0038] Furthermore, a flow meter 11 is installed on the connecting pipe between the circulating water tank 12 and the heat exchanger 6 to monitor the flow rate of the heat transfer fluid and to store a certain amount of heat transfer fluid in the circulating water tank 12. The heat exchanger 6 is equipped with a natural gas heat exchange inlet pipe and a natural gas heat exchange outlet pipe, allowing the natural gas to exchange heat with the heat transfer fluid in the heat exchanger 6.

[0039] Furthermore, a solenoid valve V1 178, a temperature sensor T1 31, and a pressure sensor A 131 are sequentially installed on the connecting pipe between the flow meter 11 and the heat exchanger 6. A branch pipe 14 is provided at the rear end of the pressure sensor A 131. The branch pipe 14 has two branches, which are respectively connected to the natural gas heat exchange inflow pipe 5 and the natural gas heat exchange outflow pipe 4. A solenoid valve V2 77 and a solenoid valve V3 76 are respectively installed on the connecting pipe between the branch pipe 14 and the natural gas heat exchange inflow pipe 5 and the natural gas heat exchange outflow pipe 4.

[0040] Because the entire system may need to be shut down when heat exchanger 6 is being maintained or repaired, the lack of redundancy design affects the continuous operation and stability of the system. In this embodiment, two parallel branch pipes 14 and solenoid valves V2 77 and V3 76 are provided. During the maintenance and repair of heat exchanger 6, the system can continue to operate stably during the maintenance period of heat exchanger 6, avoiding system shutdown due to equipment failure.

[0041] Temperature sensor T2 32 and solenoid valve V4 78 are installed on the connecting pipe between the natural gas heat exchange inflow pipe 5 and the heat exchanger 6. Temperature sensor T3 33 and solenoid valve V5 717 are installed on the connecting pipe between the natural gas heat exchange outflow pipe and the heat exchanger 6. Solenoid valve V6 71, temperature sensor T4 34, and pressure sensor C 133 are installed on the connecting pipe between the heat exchanger 6 and the phase change thermal storage unit group. Solenoid valves, pressure sensors, and temperature sensors are installed at the front and rear ends of the two phase change thermal storage units in each phase change thermal storage unit group. Water pump 2 is also installed. Furthermore, a valve is installed on the connecting pipe between the temperature sensor and pressure sensor B 132 at the rear end of each phase change thermal storage unit. For example, phase change thermal storage A has a temperature sensor T4 34 and a solenoid valve V7 711 at its front end, and a temperature sensor T5 35, a solenoid valve V8 73, and a pressure sensor B 132 at its rear end. Similarly, phase change thermal storage B has a temperature sensor T4 34 and a solenoid valve V9 712 at its front end, and a temperature sensor T6 36, a solenoid valve V10 74, and a pressure sensor B 132 at its rear end. In this embodiment, thermometers and pressure gauges are installed at both the inlet and outlet ends of heat exchanger 6 and the phase change thermal storage group. The function of the pressure gauges at the inlet and outlet of heat exchanger 6 is to calculate the pressure difference between the inlet and outlet by detecting the pressure, and to determine whether the pressure loss at the inlet and outlet is reasonable by combining this with the fluid flow rate. If the pressure loss at the inlet and outlet is too large, it indicates that heat exchanger 6 has problems such as scaling or damage, and timely repair is required. The temperature sensor T1 31 and the temperature sensor T4 34 located at the outlet of heat exchanger 6 are used together to calculate the heat exchange efficiency and heat exchange capacity of heat exchanger 6. The real-time heat exchange capacity is shown in Equation 1.

[0042]

[0043] In the formula The heat exchange power per unit time; Cp Specific heat capacity of the heat transfer fluid; T is the mass flow rate of the heat transfer fluid. out T represents the outlet temperature of the heat transfer fluid. in This refers to the inlet temperature of the heat transfer fluid.

[0044] The cumulative heat exchange over a certain period of time is calculated as shown in Equation 2:

[0045]

[0046] In the formula, Q1 is the heat absorbed by the heat transfer fluid, t0 is the initial time of the calculation, and t1 is the final time of the calculation.

[0047] The phase change thermal storage unit is connected to a domestic hot water inlet pipe at its inlet end and a domestic hot water outlet pipe at its outlet end to provide heat to users. Corresponding valves are installed on the connecting pipes: valve A714 and valve B713. The domestic hot water inlet pipe connected to phase change thermal storage unit A is also equipped with valves E79 and F710, and the domestic hot water outlet pipe connected to phase change thermal storage unit A is equipped with valves G75 and H72. The working fluid in the domestic hot water inlet pipe 81 and the domestic hot water outlet pipe 82 does not directly supply water to residents; instead, it acts as a heat transfer medium, transporting the hot fluid to the heating heat exchanger 6 to exchange heat with the residents' water supply for heating.

[0048] It also includes absorption chillers, which use heat from phase change heat storage units to drive refrigeration and generate cooling capacity.

[0049] The absorption chiller unit is a single-effect lithium bromide absorption chiller unit that can operate at temperatures above 80°C. The absorption chiller unit is equipped with a chilled water inlet pipe 83, a chilled water outlet pipe 84, a cooling water inlet pipe 85, and a cooling water outlet pipe 86. One end of the absorption chiller unit is connected to the inlet end of the phase change heat storage unit, and the other end is connected to the outlet end of the phase change heat storage unit. Valves C 715 and D 716 are respectively installed on the connecting pipes.

[0050] It also includes a controller, which is connected to each solenoid valve, valve, sensor, and water pump 2.

[0051] In this embodiment of the invention, a heat storage and utilization circulation system is formed by the domestic hot water inlet pipe 81, the domestic hot water outlet pipe 82, the chilled water inlet pipe 83, the chilled water outlet pipe 84, the absorption chiller unit 10, the cooling water inlet pipe 85, the cooling water outlet pipe 86, and the phase change heat storage unit 9. A detection system is formed by the flow meter 11, various temperature sensors, solenoid valves, valves, and pressure sensors. The controller stores and analyzes the data generated by the detection system and performs corresponding adjustments and controls based on the operating status of the flow meter 11 and sensors. Simultaneously, the controller automatically adjusts the opening and closing of various solenoid valves and valves, as well as the speed of the water pump 2, based on the collected data, thereby adjusting the operating status of the natural gas compressor outlet waste heat recovery system and enabling unmanned switching of the operating status of the parallel heat storage units. Through monitoring temperature, flow rate, and pressure, the PC-based control system ensures the high efficiency and stability of the heat exchange and storage process and optimizes energy utilization efficiency.

[0052] In this embodiment of the invention, the efficient recovery and utilization of waste heat from the natural gas compressor outlet is achieved through the coordinated operation of the heat exchange circulation system, the heat storage and utilization circulation system, the detection system, and the controller. This not only provides users with domestic hot water and cooling functions but also ensures the long-term stable operation of the system through an intelligent control system, guaranteeing energy efficiency optimization under various operating conditions and ensuring the system's stability and high-efficiency operation.

[0053] like Figure 2 The diagram illustrates the principle of the control system of the recovery system of the present invention controlling the state switching of the phase change thermal storage unit. The control system collects data from sensors and transmits the data to the PC host 1. It has pre-set calculation methods for physical quantities such as heat exchange and heat storage, and sets switching conditions and safety alarm thresholds for the thermal storage unit's operating state. After the sensor data is processed and analyzed by the pre-set algorithm, the PC host 1 determines whether to switch the operating state of the two parallel thermal storage units. If not, the system continues to operate stably. If necessary, the PC host 1 switches the thermal storage unit control state by controlling the opening and closing of solenoid valves or other valves.

[0054] The switching criteria are manually set, based on data measured by various sensors and data processed by the PC host 1. Specifically, by measuring the inlet and outlet temperatures of phase change thermal storage units 91 and 92, and combining this with operating time and physical property parameters, the heat storage capacity of the two storage units is calculated. When the heat storage capacity of the storage unit in the heat release process falls below a certain value, and the heat storage capacity of the storage unit in the heat storage process exceeds a certain value, the operating state of the two storage units will be switched. During the switching process, priority is given to ensuring heat storage demand to meet the cooling requirements of the natural gas outlet of the natural gas compressor.

[0055] The specific switching control method is as follows: After phase change thermal storage unit 91 completes heat storage and heat release, phase change thermal storage unit 91 is switched to the heat release circuit, and phase change thermal storage unit 92 is switched to the heat storage circuit. After both thermal storage units have completed their respective heat storage and heat release processes, the control system switches thermal storage unit 92 back to the heat release circuit and thermal storage unit 91 back to the heat storage circuit. The switching operation method is controlled by the PC host 1, which sequentially opens solenoid valves V10 74 and V9 712, closes solenoid valves V8 73 and V7 711, opens valves H 72 and E 79, and closes valves G 75 and F710. At this time, phase change thermal storage unit 91 switches to the heat release circuit, and phase change thermal storage unit 92 switches to the heat storage circuit. After the heat storage and release in this stage are completed, the solenoid valves V8 73 and V7 711 are opened in sequence, the solenoid valves V10 74 and V9 712 are closed, the valves G 75 and F 710 are opened, and the valves H 72 and E 79 are closed. This switches the operating state of the two heat exchangers 6 to phase change heat storage in ...

[0056] This invention designs a bypass pipeline for the main natural gas pipeline and arranges parallel heat storage units. It can achieve non-stop inspection and maintenance, non-stop heat storage and release switching, and, under the control of the PC host 1, adjust the corresponding valves based on the data from the temperature sensors at both ends of the phase change heat storage unit to achieve high efficiency in heat storage and release and enhance the circulation effect.

[0057] The method for waste heat recovery using the waste heat recovery system of this invention is as follows:

[0058] 1. When the compressor is running, close solenoid valves V3 76 and V2 77, and open main pipeline solenoid valves V1 75, V4 78, V5 717, and V6 71. Start circulating water pump 2. The heat transfer fluid is driven to flow by circulating water pump 2. The heat transfer fluid flows sequentially through the pipeline past circulating water tank 12, flow meter 11, solenoid valve V1 178, temperature sensor T1, and pressure sensor A before entering heat exchanger 6. There, it exchanges heat with natural gas, causing its temperature to rise. After the heat transfer fluid's temperature rises, it flows through the phase change thermal storage unit, transferring heat to the phase change thermal storage unit for storage. Its temperature decreases, and it then returns to circulating water tank 12 through the pipeline and circulating water pump 2 to begin the next cycle.

[0059] 2. When natural gas flows through heat exchanger 6, it enters through natural gas heat exchange inlet pipe 5, passes through temperature sensor T2, and then exits through natural gas heat exchange outlet pipe 4 after passing through temperature sensor T3 33. When heat exchanger 6 needs maintenance, solenoid valves V4 78 and V7 711 can be closed, and solenoid valves V3 76 and V2 77 can be opened to allow natural gas to flow through the bypass pipe.

[0060] 3. The thermal storage and utilization cycle system stores thermal energy in the phase change thermal storage unit 9, and uses the stored heat for heat-driven refrigeration and heat user applications through a parallel design. Specifically: During thermal storage, the heat transfer fluid thermometer, solenoid valve V7 711, or solenoid valve V9 712 flows into phase change thermal storage unit A or B, transferring heat to the phase change thermal storage unit for storage. During heat release, the low-temperature heat transfer fluid enters the phase change thermal storage unit through valve C 715 or valve A 714, absorbs heat, and after its temperature rises, it supplies heat to users through the domestic hot water inlet pipe 81 and the domestic hot water outlet pipe 82. Alternatively, hot water can be fed into the absorption chiller unit 10, using the heat in the thermal storage unit to drive refrigeration and generate cooling capacity.

[0061] During system operation, the controller collects data in real time and analyzes whether it is necessary to switch the operating status of the two phase change thermal storage devices. The specific switching process is detailed above.

[0062] The waste heat recovery system and method provided by this invention realize the reuse of natural gas waste heat. It utilizes a phase change thermal storage unit to convert and apply the heat, and at the same time, it improves the detection and control of the system through sensors and controllers. This results in a natural gas compressor outlet waste heat recovery and utilization system with high heat recovery efficiency, a sound control system, and high operational stability. It greatly reduces labor costs and system failure rate, effectively reduces system energy consumption, and provides some inspiration for the design of future compressor cooling systems.

[0063] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A natural gas compressor outlet waste heat recovery system, characterized in that, The system includes a water pump (2), a circulating water tank (12), a heat exchanger (6), and a phase change heat storage unit group. The circulating water tank (12) is located at the outlet end of the water pump (2), the heat exchanger (6) is located at the outlet end of the circulating water tank (12), and the phase change heat storage unit group is located at the outlet end of the heat exchanger (6). One or more phase change heat storage units are provided, and each phase change heat storage unit group includes two phase change heat storage units connected in parallel. The water pump (2) is located at the outlet end of the phase change heat storage unit group, forming a waste heat recovery circulation path.

2. The natural gas compressor outlet waste heat recovery system according to claim 1, characterized in that, A flow meter (11) is provided on the connecting pipe between the circulating water tank (12) and the heat exchanger (6). The heat exchanger (6) is provided with a natural gas heat exchange inflow pipe (5) and a natural gas heat exchange outflow pipe (4).

3. A natural gas compressor outlet waste heat recovery system according to claim 2, characterized in that, The flow meter (11) and the heat exchanger (6) are connected by a solenoid valve V1 (178), a temperature sensor T1 (31), and a pressure sensor A (131) in sequence. The pressure sensor A (131) is connected by a branch pipe (14) at its rear end. The branch pipe (14) is connected to the natural gas heat exchange inflow pipe (5) and the natural gas heat exchange outflow pipe (4) by a solenoid valve V2 (77) and a solenoid valve V3 (76) respectively.

4. A natural gas compressor outlet waste heat recovery system according to claim 2, characterized in that, Temperature sensor T2 (32) and solenoid valve V4 (78) are provided on the connecting pipe between the natural gas heat exchange inflow pipe (5) and the heat exchanger (6). Temperature sensor T3 (33) and solenoid valve V5 (717) are provided on the connecting pipe between the natural gas heat exchange outflow pipe (4) and the heat exchanger (6).

5. A natural gas compressor outlet waste heat recovery system according to any one of claims 1 to 4, characterized in that, The connection pipeline between the heat exchanger (6) and the phase change heat storage unit is equipped with a solenoid valve V6 (71), a temperature sensor T3 (33), and a pressure sensor B (132). The front and rear ends of the two phase change heat storage units in each phase change heat storage unit are equipped with solenoid valves, temperature sensors, and pressure sensors. The connection pipeline between the phase change heat storage unit and the water pump is equipped with a pressure sensor B (132).

6. A natural gas compressor outlet waste heat recovery system according to claim 5, characterized in that, A valve is installed on the connecting pipe between the temperature sensor and the pressure sensor B(132) at the back end of each phase change thermal storage unit.

7. A natural gas compressor outlet waste heat recovery system according to claim 1, characterized in that, The phase change thermal energy storage device is connected to a domestic hot water inlet pipe (81) at the inlet end and to a domestic hot water outlet pipe (82) at the outlet end to provide heat to users. Corresponding valves are provided on the connecting pipes.

8. A natural gas compressor outlet waste heat recovery system according to claim 1, characterized in that, It also includes an absorption chiller (10) for using heat from a phase change heat storage unit to drive refrigeration to generate cooling capacity.

9. A natural gas compressor outlet waste heat recovery system according to claim 8, characterized in that, The absorption chiller unit (10) is a single-effect lithium bromide absorption chiller unit that can operate at temperatures above 80°C. The absorption chiller unit (10) is equipped with a chilled water inlet pipe (83), a chilled water outlet pipe (84), a cooling water inlet pipe (85), and a cooling water outlet pipe (86). One end of the absorption chiller unit (10) is connected to the inlet end of the phase change heat storage device, and the other end is connected to the outlet end of the phase change heat storage device. Corresponding valves are provided on the connecting pipes. It also includes a controller, which is connected to each solenoid valve, valve, sensor, and water pump.

10. A waste heat recovery method based on a natural gas compressor outlet waste heat recovery system as described in any one of claims 1 to 9, characterized in that, The process includes the following: When the natural gas compressor is running, the circulating water pump works, and the heat transfer fluid enters the heat exchanger (6) through the circulating water tank (12), and its temperature rises after exchanging heat with the natural gas. After the temperature rises, the heat transfer fluid flows into the phase change heat storage unit for heat storage. After the temperature drops, the heat transfer fluid returns to the circulating water tank (12) via the circulating water pump (2) to enter the next cycle. The heat storage and release processes of the two phase change thermal storage devices in each group are carried out alternately. During heat storage, the heat transfer fluid flows into a phase change heat storage device to store the heat; When releasing heat, the low-temperature heat transfer fluid enters another phase change heat storage device and absorbs heat. The heat transfer fluid with increased temperature provides heat to users through the domestic hot water inlet pipe (81) and the domestic hot water outlet pipe (82), or the heat transfer fluid with increased temperature is passed into the absorption chiller unit (10) and the heat in the other phase change heat storage device is used to drive refrigeration to generate cooling capacity.

11. A method for recovering waste heat from the outlet of a natural gas compressor according to claim 10, characterized in that, The controller collects monitoring data from the corresponding sensors to determine whether it is necessary to switch the operating status of the two phase change thermal storage devices in each group. If a switch is required, the controller controls the opening and closing of the corresponding valves to switch the phase change thermal storage device to the heat storage or heat release state. If a switch is not required, the system continues to operate.

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