A halogen removal device and halogen removal system

Abstract

This invention provides a brine discharge device and system, belonging to the field of salt cavern gas storage technology. The brine discharge device includes a fluid pump driven by a motor. A slow-closing check valve assembly is installed at the outlet of the fluid pump. The slow-closing check valve assembly includes a valve disc, a valve seat, and a screen plate. The valve disc and valve seat cooperate to form a throttling pair, and the screen plate is located upstream of the throttling pair. This invention solves the problem of insufficient active anti-hammering capability of existing brine discharge pumps used in deep wells, and has the technical effect of actively preventing anti-hammering. The brine discharge system of this invention, due to the use of the aforementioned brine discharge device during discharge, can operate at a constant temperature for extended periods, thereby saving energy, shortening the gas injection and brine discharge cycle, and reducing the construction cost of the gas storage facility. When the brine discharge system of this application is used in the construction of compressed air energy storage gas storage facilities, it has the advantages of high construction efficiency and low construction cost, which is conducive to the promotion and application of large-scale compressed air energy storage systems.

Description

Technical Field

[0001] This invention relates to the field of salt cavern gas storage technology, and in particular to a brine discharge device and brine discharge system. Background Technology

[0002] Advanced compressed air energy storage systems offer significant advantages such as large storage capacity, high efficiency, long lifespan, convenient dispatch, complete pollution-free operation, and low water consumption. One type of gas storage device within compressed air energy storage systems is the salt cavern gas storage facility. Salt caverns are large cavities formed after the underground dissolution and mining of salt. The large amount of residual brine within these cavities directly reduces the effective volume available for gas storage. The core value of a salt cavern gas storage facility lies in its gas storage capacity; any residual liquid means a loss of economic benefits. Therefore, all brine within the cavity must be drained before the salt cavern gas storage facility can be put into operation.

[0003] Traditional brine removal methods involve injecting high-pressure air into the salt cavern using an air compressor or nitrogen compressor to drain the brine. This method is energy-intensive and time-consuming, and brine removal has become the largest investment cost in the construction of salt cavern gas storage facilities. Using a brine removal pump to transport high-salinity brine from deep wells to the surface or a designated treatment system is a feasible method. However, current brine removal pumps suffer from operational instability.

[0004] In the process of realizing this invention, the inventors discovered that there are at least the following problems in the prior art: one of the reasons for the unstable operation of the brine pump is that the existing brine pumps used in deep wells have an unsatisfactory ability to actively prevent water hammer. In other words, the existing brine pumps cannot actively adjust their operating conditions before or in the early stage of water hammer, and cannot suppress the generation of water hammer from the source, thus causing the brine pump to be unstable in operation. Summary of the Invention

[0005] The purpose of this invention is to provide a brine discharge device that can actively prevent water hammer and a brine discharge system that can operate stably.

[0006] To achieve this objective, a brine discharge device is provided, comprising a fluid pump driven by an electric motor. A slow-closing check valve assembly is installed at the outlet of the fluid pump. This assembly includes a valve disc, a valve seat, and a screen plate. The valve disc and valve seat cooperate to form a throttling pair, and the screen plate is positioned upstream of the throttling pair. During the start-up phase of the brine discharge device, the fluid pump speed increases, and the valve disc of the slow-closing check valve assembly is opened by the upward thrust of the brine, allowing the brine to be discharged. During the shutdown transition phase, as the fluid pump speed decreases, the closing speed of the throttling pair is controlled by the screen plate, actively adjusting the operating conditions in the early stages of water hammer.

[0007] Furthermore, the sieve plate is provided with at least one sieve hole, which utilizes the properties of high-salinity brine to provide resistance to its flow. When the fluid pump speed decreases, the valve disc is delayed in falling back due to the obstruction of the brine accumulated in the sieve hole.

[0008] Furthermore, the sieve holes are through holes, and the size of the through holes on the surface near the valve disc is larger than the size on the surface away from the valve disc, thus serving both damping / buffering and salting-out blockage functions.

[0009] Furthermore, an annular damping orifice is provided between the valve disc and the valve seat. When the fluid pump speed decreases again, a restricted backflow is formed through the damping orifice, thus limiting the rate of return of the brine column in the tubing. During brine discharge, the slow-closing check valve assembly is located inside the discharge pipe. When the valve disc opens during forward brine discharge, the brine collects in the damping orifice. When the discharge device is operating, the liquid in the damping orifice is always brine. When the fluid pump speed decreases again, a restricted backflow is formed through the damping orifice, thus limiting the rate of return of the brine column in the tubing.

[0010] Furthermore, the fluid pump is a multi-stage centrifugal pump, with its inlet located close to the bottom of the salt cavern and its outlet above the inlet. Multi-stage centrifugal pumps offer the advantage of high head and are suitable for deep brine wells.

[0011] Furthermore, the multistage centrifugal pump is driven by a sealed motor, and the transmission connection between the sealed motor and the multistage centrifugal pump uses a heavy-duty thrust bearing system.

[0012] Furthermore, the brine discharge device is also equipped with a pump body short section, which connects the outlet of the fluid pump with the throttling pair formed by the valve disc and valve seat.

[0013] On the other hand, a brine drainage system is also provided, including a suspended vertical pipe, which is fixed in the well by a hanger located at the wellhead, and a brine drainage device as described above is provided at one end of the suspended vertical pipe near the bottom of the salt cavern cavity.

[0014] Furthermore, the brine discharge device is located at the lower end of the suspended riser, or the brine discharge device is located in the extension path of the suspended riser; the slow-closing check valve assembly is located inside the suspended riser, or the slow-closing check valve assembly is located in the extension path of the suspended riser.

[0015] Furthermore, an outer sleeve located inside the well is fixedly connected to the hanger. The outer sleeve is fitted over the outside of the suspension vertical pipe, and the cable of the brine discharge device passes through the annular cavity between the outer sleeve and the suspension vertical pipe.

[0016] One of the above technical solutions has the following advantages or beneficial effects: The brine discharge device of this application, by setting a slow-closing check valve assembly at the outlet of the multi-stage centrifugal pump, achieves rectification and buffering of the inter-stage flow. Active anti-hammer operation is achieved through the fluid damping effect of the sieve plate assembly. Furthermore, an annular damping orifice is provided between the valve disc and the valve seat, forming a restricted backflow through the damping orifice, thus limiting the reflux velocity of the brine column in the tubing, thereby converting transient kinetic energy into controllable friction loss and local loss, achieving "energy dissipation" anti-hammer operation. The brine discharge system of this application, due to the use of the above-mentioned brine discharge device, has a purely mechanical slow-closing check valve assembly capable of actively preventing anti-hammer operations. This allows for long-term stable operation under deep well high-lift conditions, thereby saving energy, shortening the gas injection and brine discharge cycle, and reducing the construction cost of the gas storage facility. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the brine discharge device provided in the embodiment; Figure 2 This is a schematic diagram of the slow-closing check valve assembly of the brine discharge device provided in the embodiment; Figure 3 This is a schematic diagram of the structure of a sieve plate in the slow-closing check valve assembly provided in the embodiment; Figure 4 This is a schematic diagram of the brine removal system provided in the embodiment.

[0018] In the diagram: 10-Slow-closing check valve assembly; 11-Valve disc; 12-Valve seat; 13-Sieve plate; 131-Sieve hole; 14-Damping hole; 15-Pump body section; 16-Step fixing part; 20-Multistage centrifugal pump; 21-Inlet; 22-Outlet; 23-Enclosed impeller; 24-Gap seal; 30-Sealed motor; 31-Cable; 41-Radial bearing; 42-Heavy-duty thrust bearing; 51-Hanger; 52-Hanging riser; 53-Outer sleeve. Detailed Implementation

[0019] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0020] Example 1: like Figures 1-4As shown, this embodiment provides a brine discharge device for draining brine from a salt cavern gas storage facility. Since the salt cavern gas storage facility is located deep underground, the well used for brine discharge is a deep well. Existing brine discharge pumps in deep wells have the problem of insufficient active anti-hammer operation capability.

[0021] The brine discharge device includes a fluid pump. Since the brine discharge well is a deep well, a multi-stage centrifugal pump 20 is preferred. The multi-stage centrifugal pump 20 consists of multiple pump stages connected in series, each stage comprising an impeller and a guide vane. The impeller has a closed structure, and the pump stages of the multi-stage centrifugal pump 20 are sealed with non-contact gap seals 24. The multi-stage centrifugal pump 20 has the advantage of high head.

[0022] The fluid pump is driven by an electric motor, preferably a sealed motor 30. The transmission connection between the sealed motor 30 and the multistage centrifugal pump 20 uses a thrust bearing, such as a heavy-duty thrust bearing 42 system. Optionally, a multi-bearing thrust bearing structure with liquid film lubrication is used. Due to the highly corrosive nature of the brine in the salt cavern gas storage tank, the structures inside the fluid pump that come into contact with the brine are made of corrosion-resistant materials or coated with an anti-corrosion coating. Optionally, the pump body, enclosed impeller 23, and guide vane that come into direct contact with the brine are preferably made of duplex stainless steel. Optionally, at the connection between the sealed motor 30 and the multistage centrifugal pump 20, a radial bearing 41 is installed first, followed by a thrust bearing, i.e., the radial bearing 41 and the thrust bearing are connected in series. The radial bearing 41 is used to bear the vertical load, and the thrust bearing is used to lock the axial position.

[0023] The brine discharge device is installed below the suspension riser 52, which is fixed inside the well by a hanger 51 located at the wellhead. The brine discharge device can be directly connected to the lowest end of the suspension riser 52 (the end closest to the salt cavern), or it can be installed along the extension path of the suspension riser 52 (i.e., the path extending from the end of the suspension riser 52 towards the salt cavern), in which case the brine discharge device is connected to the bottom of the suspension riser 52 via a connector. The choice of connection method depends on the dimensional relationship between the brine discharge device and the suspension riser 52. When the brine discharge device is larger than the suspension riser 52, it is connected to the bottom of the suspension riser 52 via a connector. Alternatively, it can be connected to the bottom of the suspension riser 52 via a pipe section located at the outlet of the fluid pump of the brine discharge device. When the brine discharge device is smaller than the suspension riser 52, it can be fixed inside the suspension riser 52. A cable 31 for supplying power to the brine discharge device is led from the outside of the suspension riser 52 to the ground.

[0024] A slow-closing check valve assembly 10 is installed at the outlet of the fluid pump. The slow-closing check valve assembly 10 includes a pump body section 15, which is used to connect to the outlet of the fluid pump, thus connecting the slow-closing check valve assembly 10 and the outlet of the fluid pump. The slow-closing check valve assembly 10 enables proactive adjustment of the operating conditions before or in the early stages of water hammer, suppressing the problem of water hammer at its source.

[0025] The slow-closing check valve assembly 10 includes a valve disc 11, a valve seat 12, and a screen plate 13. The valve disc 11 and the valve seat 12 cooperate to form a throttling pair, which is a fitting relationship used to regulate flow rate. In this embodiment, the valve disc 11 and the valve seat 12 are mainly used to regulate flow rate, allowing a gap between the valve disc 11 and the valve seat 12.

[0026] A sieve plate 13 is installed upstream of the throttling device. During normal brine discharge, the sieve plate 13 is located on the inflow side of the brine, i.e., upstream of the throttling device. From the working state, the sieve plate 13 is located below the throttling device formed by the valve disc 11 and the valve seat 12. The sieve plate 13 can be fixed inside the valve seat 12, or it can be fixed to the inner wall of the pump body section 15, or it can be fixed inside the stepped fixing part 16 at the end of the pump body section 15. Of course, the stepped fixing part 16 can also be set inside the valve seat 12. The sieve plate 13 realizes the rectification and buffering of the brine flow at this point, realizes the controllable adjustment of the internal flow of the multi-stage centrifugal pump 20, and effectively reduces the risk of turbulence and backflow.

[0027] The sieve plate 13 is an annular or disc-shaped pressure plate, and at least one sieve hole 131 is provided on the sieve plate 13. The sieve hole 131 is a through hole. Optionally, multiple sieve holes 131 are evenly arranged on the sieve plate 13. Since the brine passing through the sieve plate 13 is high-salinity brine, the sieve hole 131 utilizes the properties of high-salinity brine to provide resistance to its flow. However, on the other hand, the sieve plate cannot completely block the passage of brine. Therefore, the sieve hole has both damping / buffering and salt precipitation clogging functions.

[0028] Optionally, the size of the sieve hole 131 on the surface near the valve disc 11 is larger than the size on the surface away from the valve disc 11. From the working state, the sieve hole 131 is a through hole with a larger upper diameter and a smaller lower diameter, so that the resistance provided by the sieve plate 13 is sufficiently large when the fluid pump stops. Further, the diameter of the larger hole at the top of the sieve hole 131 is larger than the diameter of the smaller hole at the bottom of the sieve hole 131. Further, the morphology of the sieve hole 131 is an inverted funnel-shaped hole or an inverted cone-shaped hole, which can reduce crystal adhesion and salt buildup at the hole opening.

[0029] Optionally, the average of the diameter of the large hole above the sieve hole 131 and the diameter of the small hole below the sieve hole 131 is called the equivalent diameter. In this embodiment, the equivalent diameter dmin of the sieve hole 131 is ≥3mm to avoid salt precipitation bridging and blockage of the sieve hole 131 during temperature fluctuations, local vaporization, or shutdown and static periods.

[0030] The valve disc 11 and valve seat 12 of the slow-closing check valve assembly 10 cooperate to form a throttling pair. The valve disc 11 and the screen plate 13 are arranged coaxially and can move along the valve seat 12. The valve disc 11 opens during forward brine discharge and automatically falls back to the valve seat 12 under its own gravity when the fluid pump stops or when there is a backflow tendency of brine at this point. An annular damping orifice 14 is provided between the valve disc 11 and the valve seat 12. During forward brine discharge, brine collects in the damping orifice 14 as the valve disc 11 opens. The volume of the damping orifice 14 decreases as the valve disc 11 rises and increases as the valve disc 11 falls. When the brine discharge device is working, the liquid in the damping orifice 14 is always brine. When the fluid pump speed decreases again, a restricted backflow is formed through the damping orifice 14, which restricts the rate of fall of the brine column in the tubing.

[0031] In this embodiment, the brine discharge device is fixed inside the suspension riser 52, or the extension path of the suspension riser 52 is fixed through a pipe section. Specifically, the slow-closing check valve assembly 10 is located inside the suspension riser 52, or the slow-closing check valve assembly 10 is located in the extension path of the suspension riser 52, and the fluid pump is located outside the suspension riser 52. During brine discharge, the suspension riser 52 or pipe section is filled with brine. Since the valve disc 11 and valve seat 12 in this embodiment cooperate to form a throttling pair, after the valve disc 11 is closed, there will be a gap between the valve disc 11 and the valve seat 12. The damping orifice 14 communicates with the brine in the pipe, and the damping orifice 14 plays a bypass role. The restricted backflow is formed through the damping orifice 14, so that the fall speed of the brine column in the pipe is restricted by throttling.

[0032] In this embodiment, the brine discharge device is installed at the lowest end of the suspended vertical pipe 52. During normal brine discharge, the sealed motor 30 of the brine discharge device is submerged in the salt cavern near the bottom of the cavity. The brine enters from the inlet 21 located below the multi-stage centrifugal pump 20, is lifted by the multi-stage centrifugal pump 20, and flows out from the outlet 22 located above the multi-stage centrifugal pump 20. After flowing out, it enters the suspended vertical pipe 52 through the slow-closing valve 11 and is discharged to the ground.

[0033] When the brine discharge device is in the start-up phase, the fluid pump speed increases, and the valve disc 11 of the slow-closing check valve assembly is pushed open by the upward thrust of the brine, thus allowing the brine to be discharged.

[0034] When the brine discharge device is in the shutdown transition phase, as the fluid pump speed begins to decrease, the valve disc 11 is delayed in falling back due to the brine accumulated in the screen holes 131 on the screen plate 13, and slowly approaches the valve seat 12. The closing speed of the valve disc 11 is controlled by the screen plate 13. At the same time, the brine begins to fill the damping orifice 14. This avoids the pressure surge and valve disc 11 slapping caused by the "instantaneous closure" of a traditional check valve.

[0035] When the brine discharge device is in the shutdown and fall-off phase: when the pump speed drops to near zero, after the valve disc 11 approaches the valve seat 12 and comes to a relative stop, a restricted backflow is formed through the damping hole 14, which restricts the fall speed of the brine column in the tubing, thereby converting the transient kinetic energy into controllable friction loss and local loss, and realizing "energy dissipation" water hammer.

[0036] In this embodiment, the brine discharge device achieves rectification and buffering of the interstage flow by incorporating a slow-closing check valve assembly at the outlet of the multi-stage centrifugal pump 20. Active flood prevention of brine hammer is achieved through the fluid damping effect of the sieve plate 13 assembly. The controllable adjustment of the internal flow state of the multi-stage centrifugal pump 20 is achieved through the design of the through-hole structure parameters of the sieve plate 13, effectively reducing the risks of turbulence and backflow. The damping orifice 14 creates a restricted backflow, limiting the reflux velocity of the brine column within the tubing, thereby converting transient kinetic energy into controllable friction loss and local loss, achieving "energy-dissipating" flood prevention of brine hammer.

[0037] Because the slow-closing check valve assembly of this application is a purely mechanical structure, it can operate stably for a long time under high-lift conditions in deep wells, saving electrical energy, improving brine discharge efficiency, and reducing construction costs. Based on this, the brine discharge device of this embodiment can utilize a deep well pump to extract brine for discharge, saving electrical energy, shortening the gas injection and brine discharge cycle, and reducing the construction cost of the gas storage facility.

[0038] Example 2: like Figure 4 As shown, this embodiment provides a brine drainage system, which includes multiple downhole tubing strings fixed inside the well by a hanger 51 located at the wellhead. The brine drainage system of this embodiment includes a suspension riser 52, which is fixed inside the well by the hanger 51 located at the wellhead. A brine drainage device as described in Embodiment 1 is provided at one end of the suspension riser 52 near the bottom of the salt cavern cavity.

[0039] Furthermore, in Embodiment 1, the brine discharge device is located at the lower end of the suspension vertical pipe 52, or the brine discharge device is located in the extension path of the suspension vertical pipe 52; the slow-closing check valve assembly 10 is located inside the suspension vertical pipe 52, or the slow-closing check valve assembly 10 is located in the extension path of the suspension vertical pipe 52.

[0040] Furthermore, an outer sleeve 53 located inside the well is fixedly connected to the hanger 51. The outer sleeve 53 is sleeved on the outside of the suspension vertical pipe 52, and the cable 31 of the brine discharge device passes through the annular cavity between the outer sleeve 53 and the suspension vertical pipe 52.

[0041] The brine discharge system in this embodiment, by using the brine discharge device of Embodiment 1, can save electricity, shorten the gas injection and brine discharge cycle, and reduce the construction cost of the gas storage facility.

[0042] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A brine discharge device, characterized in that, The fluid pump is equipped with a slow-closing check valve assembly at its outlet. The slow-closing check valve assembly includes a valve disc, a valve seat, and a screen plate. The valve disc and valve seat cooperate to form a throttling pair, and the screen plate is located upstream of the throttling pair. When the fluid pump speed decreases, the closing speed of the throttling pair is controlled by the screen plate, which actively adjusts the operating conditions in the early stage of water hammer.

2. The brine discharge device according to claim 1, characterized in that, The sieve plate is provided with at least one sieve hole. When the speed of the fluid pump decreases, the valve disc is delayed in falling back due to the obstruction of the brine accumulated in the sieve hole.

3. The brine discharge device according to claim 2, characterized in that, The sieve holes are through holes, and the size of the through holes on the surface near the valve disc is larger than the size on the surface away from the valve disc.

4. The brine discharge device according to claim 1, characterized in that, An annular damping orifice is provided between the valve disc and the valve seat. When the fluid pump speed decreases again, a restricted backflow is formed through the damping orifice, which restricts the rate of return of the brine column in the tubing.

5. The brine discharge device according to claim 1, characterized in that, The fluid pump is a multi-stage centrifugal pump. The inlet of the fluid pump is located near the bottom of the salt cavern, and the outlet of the fluid pump is above the inlet.

6. The brine discharge device according to claim 5, characterized in that, The multistage centrifugal pump is driven by a sealed motor, and the transmission connection between the sealed motor and the multistage centrifugal pump uses a heavy-duty thrust bearing system.

7. The brine discharge device according to claim 1, characterized in that, The brine discharge device is also equipped with a pump body short section, which connects the outlet of the fluid pump with the throttling pair formed by the valve disc and valve seat.

8. A brine removal system, characterized in that, It includes a suspended vertical pipe, which is fixed inside the well by a hanger located at the wellhead, and a brine discharge device as described in any one of claims 1 to 7 is provided at one end of the suspended vertical pipe near the bottom of the salt cavern cavity.

9. The brine removal system according to claim 8, characterized in that, The brine discharge device is located at the lower end of the suspended riser, or the brine discharge device is located in the extension path of the suspended riser; the slow-closing check valve is located inside the suspended riser, or the slow-closing check valve is located in the extension path of the suspended riser.

10. The brine discharge system according to claim 8, characterized in that, An outer sleeve located inside the well is also fixedly connected to the hanger. The outer sleeve is fitted outside the hanging vertical pipe, and the cable of the brine discharge device passes through the annular cavity between the outer sleeve and the hanging vertical pipe.

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