Large-belt-liquid open wave rotor gas wave refrigerator

Abstract

The application discloses a large-liquid-carrying open wave rotor gas wave refrigerator, and belongs to the technical field of gas expansion refrigeration. The refrigerator is mainly composed of a core component wave rotor, a two-phase nozzle and a shell and other components. The two-phase nozzle adopts a three-dimensional tapered streamline design with a liquid discharge function, and realizes pre-separation of gas-liquid two phases by utilizing inertial force; the wave rotor adopts an open structure design, and an open form is arranged on a top circular surface of a wave rotor channel part, and cooperates with a liquid collecting ring provided with a liquid discharge structure, so that liquid accumulation in the pipe is discharged from the wave rotor in time, thereby reducing the adverse effect of liquid accumulation on the wave motion in the pipe, improving the liquid-carrying operation capacity and refrigeration performance of the gas wave refrigerator, and realizing high-efficiency gas wave expansion refrigeration under a large-liquid-carrying working condition.

Description

Technical Field

[0001] A large liquid-filled open-type wave rotor gas wave refrigerator belongs to the field of gas expansion refrigeration technology. Background Technology

[0002] Natural gas is recognized worldwide as the cleanest fossil fuel, and its development and utilization will continue to grow under the impetus of economic development and low-carbon energy conservation. Direct expansion refrigeration is a commonly used process in large-scale natural gas processing, effectively utilizing formation pressure energy and reducing losses caused by direct heat exchange and cooling. However, natural gas pipelines carry a certain amount of liquid, including liquid alcohol injected for antifreeze purposes and liquid generated during operation due to fluctuations in operating conditions and changes in the performance of pre-separation equipment. Furthermore, natural gas expansion and cooling also produces significant amounts of gas liquefaction, necessitating that expansion refrigeration equipment be able to operate with liquid carrying capacity. Simultaneously, with the depletion-type extraction of natural gas, the content of heavy hydrocarbons and water in the gas phase increases over time, further increasing the requirements for liquid carrying capacity in expansion refrigeration equipment. Therefore, expansion refrigeration of gases with large liquid carrying capacity has significant practical and theoretical value.

[0003] In addition, in common mixed gas refrigeration systems, the expansion of gas into the two-phase region can provide more cooling capacity, thereby improving the system's economy. Therefore, the refrigeration industry also needs high-efficiency refrigeration technology with large liquid load.

[0004] Currently, the main expansion refrigeration equipment includes JT expansion valves, turbine expanders, and wave-type refrigerators. Among these, the JT expansion valve is a static device with a simple structure, convenient maintenance, and easy operation, making it widely used. However, its application results in significant pressure energy loss, leading to low economic efficiency. Therefore, the use of turbine expanders, which possess isentropic expansion properties, to replace JT expansion valves has been proposed. Some researchers have found that this method can reduce power consumption by 20% and heat exchange by approximately 9%. However, the high-speed nature of turbine expanders makes them susceptible to droplet erosion during natural gas expansion refrigeration, causing equipment failure and increasing investment costs. Compared to turbine expanders, wave-type refrigerators also possess good isentropic expansion properties, enabling the recovery and utilization of gas pressure energy; furthermore, their relatively low operating speed (2000~3000 rpm) reduces their susceptibility to droplet erosion, making them ideal for replacing JT expansion valves in gas expansion refrigeration.

[0005] The gas wave chiller has four ports: a high-pressure injection port, a high-temperature exhaust port, a low-pressure port, and a low-temperature exhaust port. The main working process is as follows: High-pressure gas enters the wave rotor through the high-pressure injection nozzle, forming a shock wave that compresses the existing gas in the tube. The high-pressure gas transfers its energy to the existing gas in the tube, causing it to expand to a low-temperature, low-pressure state. The energy-receiving gas in the tube becomes high-temperature, high-pressure gas and is discharged from the high-temperature exhaust port. Meanwhile, the existing gas in the tube enters the oscillating tube through the low-pressure port, which can originate from the high-temperature exhaust port within the device or from other streams in the process system. Thus, the expansion work of the high-pressure gas is converted into expansion work, low-pressure gas pressure energy, and thermal energy, achieving the purpose of energy output.

[0006] When the gas refrigeration unit is operating, the incoming gas in the wave refrigeration unit carries liquid droplets and the liquid formed by the aggregation of expanded and condensed droplets. Due to centrifugal force, this liquid accumulates on the inner wall of the outer hub. Driven by the periodic jets of high-pressure air, the accumulated liquid flows back and forth on the wall of the wave rotor. This liquid accumulation can cause the following problems: 1) The flow of liquid disrupts the gas wave pattern, causing the matching relationship between the wave system inside the wave rotor and each port to deviate significantly from the design point, resulting in unstable equipment operation. 2) Increased drag during the formation of the incident shock wave reduces the shock wave intensity, resulting in decreased efficiency of energy transfer between gases. 3) The accumulated liquid evaporates again under the action of the shock wave, causing the liquid content to decrease after the expansion of the two-phase working fluid, which affects the cooling performance of the equipment.

[0007] Therefore, effectively and promptly draining the liquid accumulated in the wave rotor channel has become a key technology for promoting the application of wave refrigerators in the field of gas expansion refrigeration. Summary of the Invention

[0008] To address the aforementioned issues, this invention proposes a large-capacity open-type wave rotor air-wave refrigerator, with an open-type wave rotor and two-phase nozzles as core components. This system can pre-separate the inlet droplets of the refrigerator and promptly discharge the liquid formed by the agglomeration of incoming droplets and expanded condensed droplets within the wave rotor, thereby improving the refrigeration performance of the refrigerator.

[0009] The technical solution adopted in this invention is: A large-scale open-type wave rotor gas wave refrigerator, capable of stable operation in the two-phase region, comprises an expansion end cap, an outer shell, and a compression end cap, forming the refrigerator housing. An open-type wave rotor is fixedly connected to the main shaft within the housing and is driven to rotate by a motor. The open-type wave rotor is an integral unit consisting of an inner hub, blades, and an outer hub. The inner hub is fixedly connected to the main shaft, while the outer hub does not completely cover the wave rotor, forming an open structure. Several blades are evenly distributed circumferentially to form flow channels. Those covered by the outer hub form independent closed flow channels, while the open flow channels without the outer hub form a clearance fit with a liquid collection ring, used to collect and discharge liquid droplets carried by the incoming gas and the liquid formed by the aggregation of expanded condensed droplets within the wave rotor. The expansion end cap is equipped with a high-pressure injection nozzle and a low-temperature exhaust port, while the compression end cap is equipped with a high-temperature exhaust port and a medium-pressure return port.

[0010] The high-pressure gas jet nozzle is a two-phase nozzle with a three-dimensional tapered streamline shape. It can be bent, arc-shaped, U-shaped, or serpentine, with a cross-sectional shape of circular, rectangular, elliptical, or trapezoidal. It is equipped with one or more drainage holes.

[0011] The open-type wave rotor is an axial wave rotor or a conical wave rotor; the blades are straight blades, curved blades or variable cross-section blades, that is, the present invention is applicable to straight-channel wave rotors, curved-channel wave rotors and variable cross-section channel wave rotors, etc.

[0012] The open-type wave rotor can be open at the expansion end, open at the compression end, open in the middle section, or fully open; that is, the outer hub covers part of the wave rotor channel, and the other parts are set to be open. The open area can be the expansion end, the compression end, the middle section (the middle part of the channel), or the entire channel.

[0013] The clearance between the liquid collecting ring and the blade tip of the open-type wave rotor ranges from 0.05mm to 0.5mm; the axial clearance ranges from 0.1mm to 1mm.

[0014] The liquid collecting ring is provided with a drain groove, drain hole, or blade tip gap sealing structure. The drain groove can be a straight groove or a curved groove. In order not to affect the energy transfer of the gas wave in the flow channel, the drain groove should be designed to avoid the position between the high-pressure gas jet nozzle and the high-temperature exhaust port.

[0015] The liquid in the liquid collection ring is either collected and discharged separately or discharged into the low-temperature exhaust gas.

[0016] A working method for a large liquid-filled open-type wave rotor gas wave refrigerator: The motor drives the open-type wave rotor to rotate. During the rotation, the open-type wave rotor periodically connects and closes with the nozzles and ports at both ends. When the rotor channel is connected to the high-pressure injection nozzle, high-pressure air is injected into the wave rotor channel and forms a shock wave S1. Then the rotor channel is offset and the high-pressure injection nozzle is closed. The shock wave S1 transfers energy to the gas in the pipe. The high-pressure air loses energy after expansion and transforms into a low-temperature, low-pressure state. When the rotor channel is connected to the low-temperature exhaust port, the low-temperature exhaust is discharged from the low-temperature exhaust port. During high-pressure air intake, the gas state in the pipe is compressed from medium-pressure return gas to high-temperature exhaust. When the wave rotor is connected to the high-temperature exhaust port, the high-temperature exhaust is discharged from the wave rotor through the high-temperature exhaust port. During the process of high-pressure intake gas expansion to low-temperature exhaust gas, the gas state crosses the saturation curve and enters the two-phase region. The incoming gas carries liquid droplets and liquid formed by the aggregation of expanded condensed droplets. The liquid is collected separately or merged into the high-temperature exhaust gas.

[0017] The beneficial effects of this invention are: Gas wave refrigerators utilize isentropic expansion cooling achieved by compressing low-pressure gas with high-pressure gas, requiring only low rotational speeds to convert and recover energy. However, the wave rotor, the core component of the gas wave refrigerator, currently has its entire channel length covered by the outer hub. This prevents the complete removal of liquid droplets carried by the intake gas during the cooling process, as well as the agglomeration of expanded condensate droplets, leading to liquid accumulation within the wave rotor. This liquid accumulation further disrupts the wave motion process within the rotor, reduces energy conversion efficiency, and causes instability in equipment operation.

[0018] The open design of the wave rotor allows for timely drainage of accumulated liquid within the rotor, resulting in benefits including: 1) Timely discharge of liquid accumulated inside the wave rotor reduces the degree of disorder in gas wave behavior and avoids equipment operation problems caused by the deviation of the wave system and port matching relationship from the design point; 2) The intensity of the incident shock wave is no longer reduced due to the resistance of the accumulated liquid, which improves the efficiency of the external transmission of high-pressure gas energy in the wave rotor; 3) Timely drainage of accumulated liquid prevents secondary evaporation of liquid under the action of shock wave, increases the liquid content after the expansion of the two-phase working fluid in the wave rotor, and improves the refrigeration performance of the gas wave refrigerator and even the entire system.

[0019] This invention enables the gas wave refrigerator to have the ability to carry large amounts of liquid and operate at high efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a large liquid-filled open-type wave rotor gas wave refrigerator.

[0021] Figure 2 The diagram shows three open-type wave rotor structures.

[0022] Figure 3 This is a schematic diagram of a two-phase nozzle structure.

[0023] Figure 4 This is a schematic diagram illustrating the working principle of an air-wave refrigeration machine.

[0024] Figure 5 This is a temperature entropy diagram showing the working process of the air-wave refrigerator.

[0025] Figure 6 This is a schematic diagram of the three-dimensional structure of an open-type wave rotor.

[0026] Figure 7 This is a schematic diagram of an open-type conical wave rotor structure.

[0027] Figure 8 This is a schematic diagram of the three-dimensional structure of the liquid collecting ring.

[0028] Figure 9 This is a schematic diagram of the open-type wave rotor and the liquid collecting ring.

[0029] Figure 10 This is a schematic diagram showing the flow direction of the two collected liquids.

[0030] In the diagram: 1. Low-temperature exhaust port; 2. Expansion end bearing; 3. Expansion end bearing cover; 4. High-pressure injection nozzle; 5. Expansion end cover; 6. Outer casing; 6-1. Liquid collection port; 7. Open wave rotor; 7-1. Inner hub; 7-2. Blade; 7-3. Outer hub; 8. Liquid collection ring; 8-1. Drainage groove; 9. Main shaft; 10. Medium-pressure return port; 11. Compression end cover; 12. Compression end bearing; 13. Compression end bearing cover; 14. Coupling; 15. Motor; 16. High-temperature exhaust port; a. High-pressure intake; b. High-temperature exhaust; c. Medium-pressure return gas; d. Low-temperature exhaust; S1. Incident shock wave; E1. Incident expansion wave; E2. Reflected expansion wave; C1. Reflected compression wave; C2. Reverse compression wave; CH. Hot and cold gas contact surface. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0032] Figure 1 The diagram shows a structural schematic of a large-scale open-type wave rotor gas wave refrigerator. This novel two-phase gas wave refrigerator mainly includes an expansion end cap 5, an outer casing 6, an open-type wave rotor 7, a liquid collecting ring 8, a main shaft 9, a compression end cap 11, a motor 15, a high-pressure injection nozzle 4, a high-temperature exhaust port 16, a medium-pressure reflux port 10, a low-temperature exhaust port 1, and other auxiliary structures. The open-type wave rotor 7 is fixedly connected to the main shaft 9 and is driven to rotate by the motor 15.

[0033] The open-type wave rotor 7 is an integral unit composed of an inner hub 7-1, blades 7-2, and an outer hub 7-3. The blades 7-2 are evenly distributed circumferentially to form several relatively independent flow channels. The outer hub 7-3 only covers the expansion end portion, thus maintaining independent closed flow channels at the expansion end of the wave rotor. The compression end of the wave rotor remains open, forming a clearance fit with a liquid collecting ring 8 equipped with a drain groove 8-1. The liquid collecting ring 8 is fixed to the outer casing 6, which has a liquid collecting port 6-1.

[0034] Figure 2 This is a schematic diagram of three structures derived from an open-type wave rotor. The outer hub 7-3 covers the expansion end, compression end, and middle part of the wave rotor channel, respectively. There is a slit between the stationary outer shell and the rotating oscillating tube. The centrifugal force of rotation allows the liquid formed by the airflow carrying droplets and the agglomeration of expanded condensed droplets to be discharged from the channel through the slit.

[0035] Figure 3 This is a schematic diagram of a two-phase nozzle structure. The flow channel is designed as a three-dimensional curved and tapered streamline. The liquid-laden gas is turned and accelerated through the nozzle. The liquid at the inlet and the condensate after cooling are affected by inertia and achieve preliminary pre-separation from the gas. The accumulated film-forming liquid is discharged from the drain hole and finally flows into the low-temperature exhaust gas d for discharge, thereby reducing the amount of liquid entering the oscillating tube.

[0036] Figure 4 The diagram shows the basic working principle of the wave chiller. Its operation is as follows: The motor drives the wave rotor to rotate. During rotation, the wave rotor periodically connects and closes with the nozzles and ports at both ends. When connected to the high-pressure injection nozzle 4, high-pressure gas is injected into the wave rotor channel, forming a shock wave S1. The shock wave S1 transfers energy to the gas inside the pipe. The high-pressure gas loses energy after expansion and expands to a low-temperature, low-pressure state. This state is enhanced by the incident expansion wave E1 and the reflected expansion wave E2. When connected to the high-temperature exhaust port 16, the gas inside the pipe, having received energy, heats up and pressurizes, and is discharged from the wave rotor through the high-temperature exhaust port 16.

[0037] Figure 5 The diagram shows the temperature-entropy curve of the two-phase gas wave refrigerator during the refrigeration process. It can be seen that when the high-pressure gas a expands to the low-temperature gas d, the gas phase crosses the saturation curve and enters the two-phase region, forming a condensed liquid. The gas state inside the pipe changes from medium-pressure reflux gas c to high-temperature gas b, achieving energy recovery.

[0038] Figure 6This is a three-dimensional structural diagram of an open-type wave rotor 7. The open-type wave rotor 7 consists of an inner hub 7-1, blades 7-2, and an outer hub 7-3. The inner hub 7-1 is fixedly connected to the main shaft 9. Several blades 7-2 are evenly distributed circumferentially to form an equal number of flow channels, serving as the site for continuous operation of the gas wave cooling. Blades 7-2 include, but are not limited to, straight blades, curved blades, and variable cross-section blades. The outer hub 7-3 only covers the expansion end of the wave rotor, forming independent closed flow channels at the expansion end to prevent gas leakage between flow channels, which would weaken the expansion wave intensity and thus reduce cooling performance. At the compression end, there is no outer hub 7-3; the flow channel is open and forms a clearance fit with the liquid collecting ring 8. The open-type wave rotor 7 includes, but is not limited to, axial wave rotors and conical wave rotors. The structural form of a conical wave rotor is shown below. Figure 7 As shown.

[0039] Figure 8 The diagram shows a three-dimensional structural schematic of the liquid collecting ring 8. The inner wall of the liquid collecting ring 8 is provided with drainage grooves 8-1 for collecting liquid discharged from the wave rotor flow channel. Multiple drainage grooves 8-1 can be provided on the inner wall and interconnected for better liquid collection. The structural forms of the drainage grooves 8-1 include, but are not limited to, straight grooves and curved grooves. The liquid collecting ring 8 can also be provided with various types or functions of structures, such as drainage holes or sealing structures for blade tip clearance sealing.

[0040] Figure 9 A schematic diagram of the fit between the open-type wave rotor 7 and the liquid collecting ring 8 is provided. The installation position of the liquid collecting ring 8 should avoid the energy transfer area between the high-pressure jet nozzle 4 and the high-temperature exhaust port 16 to prevent interference with the motion of the related wave system and affect the energy transfer process. The tip clearance between the liquid collecting ring 8 and the open-type wave rotor 7 ranges from 0.05 mm to 0.5 mm; the axial clearance ranges from 0.1 mm to 1 mm.

[0041] The liquid collected by the liquid collection ring 8 can be collected separately or merged into the cryogenic exhaust gas according to specific process requirements. Figure 10 Two schematic diagrams of liquid flow directions are given.

[0042] When the equipment is working, motor 15 drives the open wave rotor 7 to rotate. During the rotation, the open wave rotor 7 periodically connects and closes with the nozzles and ports at both ends. When connected to the high-pressure injection nozzle 4, high-pressure intake gas a is injected into the wave rotor channel and forms a shock wave S1. The shock wave S1 transfers energy to the gas in the pipe. After expanding, the high-pressure intake gas a loses energy and expands to a low-temperature, low-pressure state, becoming low-temperature exhaust gas d. Low-temperature exhaust gas d is discharged from the low-temperature exhaust port 1. The gas state in the pipe changes from medium-pressure return gas c to high-temperature exhaust gas b. When the wave rotor is connected to the high-temperature exhaust port 16, the high-temperature exhaust gas b is discharged from the wave rotor through the high-temperature exhaust port 16.

[0043] The process for collecting liquids separately is as follows: As the high-pressure intake gas a expands to the low-temperature exhaust gas d, the gas state crosses the saturation curve and enters the two-phase region. The condensed droplets generated converge with the droplets carried by the incoming flow to form a film. The film flows into the outer shell 6 through the slit gap between the open wave rotor 7 and the liquid collection ring 8, and through the drain groove 8-1 on the liquid collection ring 8. Finally, it is collected separately through the liquid collection port 6-1.

[0044] The process of liquid entering the cryogenic exhaust gas is as follows: As the high-pressure intake gas a expands to the low-temperature exhaust gas d, the gas state crosses the saturation curve and enters the two-phase region. The condensate droplets generated converge with the droplets carried by the incoming flow to form a film. The film flows into the outer shell 6 through the narrow gap between the open wave rotor 7 and the liquid collecting ring 8, and through the drain groove 8-1 on the liquid collecting ring 8. After passing through the narrow gap between the open wave rotor 7 and the outer shell 6, it finally merges into the low-temperature exhaust gas d.

[0045] The applications of the device of this invention include, but are not limited to, low-temperature gas dehydration, low-temperature gas distillation, and gas expansion refrigeration.

Claims

1. A large-scale open-type wave rotor air-wave refrigerator with liquid loading, characterized in that: It consists of an expansion end cap (5), an outer shell (6), and a compression end cap (11) forming the air-wave refrigerator housing. Inside the housing, an open-type wave rotor (7) is fixedly connected to the main shaft (9) and is driven to rotate by a motor (15). The open-type wave rotor (7) is an integral unit composed of an inner hub (7-1), blades (7-2), and an outer hub (7-3). The inner hub (7-1) is fixedly connected to the main shaft (9), and the outer hub (7-3) does not completely cover the wave rotor, forming an open structure. Several blades The plates (7-2) are evenly distributed in the circumference to form flow channels. The ones covered by the outer hub (7-3) form independent closed flow channels. The open flow channels without the outer hub (7-3) form a gap fit with the liquid collection ring (8) to collect and discharge the liquid formed by the inflow gas carrying liquid droplets and the expansion condensation liquid droplets agglomeration in the wave rotor. The expansion end cap (5) is provided with a high-pressure gas injection nozzle (4) and a low-temperature exhaust port (1). The compression end cap (11) is provided with a high-temperature exhaust port (16) and a medium-pressure return port (10).

2. The large liquid-filled open-type wave rotor air wave refrigerator according to claim 1, characterized in that: The high-pressure gas jet nozzle (4) is a two-phase nozzle, which adopts a bent shape, a circular arc bend, a U-shape or a serpentine shape, and has a cross-section of a circle, a rectangle, an ellipse or a trapezoid, and is provided with a drain hole.

3. A large-scale open-type wave rotor air wave refrigerator according to claim 1, characterized in that: The open-type wave rotor (7) is an axial wave rotor or a conical wave rotor; the blade (7-2) is a straight blade, a curved blade or a variable cross-section blade.

4. A large-scale open-type wave rotor air-wave refrigerator with liquid loading according to claim 1, characterized in that: The open-type wave rotor (7) can be open at the expansion end, open at the compression end, open in the middle section, or fully open.

5. A large-scale open-type wave rotor gas wave refrigerator with liquid loading according to claim 1, characterized in that: The blade tip clearance between the liquid collecting ring (8) and the open wave rotor (7) ranges from 0.05 mm to 0.5 mm; the axial clearance ranges from 0.1 mm to 1 mm.

6. A large liquid-filled open-type wave rotor air wave refrigerator according to claim 5, characterized in that: The liquid collection ring (8) is provided with a drain trough or drain hole. The drain trough is a straight trough or a curved trough, and the number of troughs is selected according to the liquefaction amount.

7. A large-scale open-type wave rotor air wave refrigerator according to claim 5, characterized in that: The liquid in the liquid collection ring (8) is collected and discharged separately or discharged into the low-temperature exhaust gas.

8. The working method of a large liquid-filled open-type wave rotor gas wave refrigerator according to any one of claims 1-7, characterized in that: The motor (15) drives the open wave rotor (7) to rotate. During the rotation, the open wave rotor (7) periodically connects and closes with each nozzle and port at both ends. When the rotor channel is connected to the high-pressure injection nozzle (4), the high-pressure intake (a) is injected into the wave rotor channel and forms a shock wave S1. Then the rotor channel is closed after being offset from the high-pressure injection nozzle (4). The shock wave S1 transfers energy to the gas in the pipe. The high-pressure intake (a) loses energy after expansion and transforms into a low-temperature and low-pressure state. When the rotor channel is connected to the low-temperature exhaust port (1), the low-temperature exhaust (d) is discharged from the low-temperature exhaust port (1). When the high-pressure intake is in progress, the gas state in the pipe is compressed from medium-pressure return gas (c) to high-temperature exhaust (b). When the wave rotor is connected to the high-temperature exhaust port (16), the high-temperature exhaust (b) is discharged from the wave rotor through the high-temperature exhaust port (16). During the process of high-pressure intake (a) expanding to low-temperature exhaust (d), the gas state crosses the saturation curve and enters the two-phase region. The incoming gas carries liquid droplets and liquid formed by the aggregation of expanded condensed droplets. The liquid is collected separately or merged into the high-temperature exhaust.

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