Online backwash flash vapor recovery system and control method

Abstract

This application provides an online backwash flash vapor recovery system and control method. The system includes: a compression unit inlet connected to the flash tank gas phase outlet; a filter pipeline sequentially connected to the compression unit outlet, a filter valve, a first end of an vent pipeline, and the inlet of a membrane separation device; a vent pipeline connected to a vent valve; a permeate pipeline sequentially connected to the membrane separation device permeate outlet, a first end of an adsorption guide pipeline, and an inlet valve; an adsorption guide pipeline connected to an adsorption guide valve; a non-permeate gas pipeline sequentially connected to the membrane separation device non-permeate gas outlet, a second end of an adsorption guide pipeline, and an adsorption device; a backwash pipeline sequentially connected to the permeate gas pipeline, a backwash valve, and the gas storage tank outlet; an inlet pipeline sequentially connected to the second end of the permeate gas pipeline and the buffer tank inlet; a flow meter connected to the inlet pipeline, the flow meter detecting the gas flow rate and generating a first signal; and a controller controlling the on / off states of the filter valve, vent valve, inlet valve, adsorption guide valve, and backwash valve based on the first signal.

Description

Technical Field

[0001] This application relates to the field of automated natural gas processing technology, and in particular to an online backflushing flash vapor recovery system and control method. Background Technology

[0002] Helium, a rare and vital resource, plays an irreplaceable role in numerous high-tech fields, such as deep-sea diving, aerospace engineering, medicine (e.g., MRI), and semiconductor manufacturing. Cryogenic helium extraction is an advanced technology that separates helium from natural gas based on the critical temperature differences among its components. Through cryogenic processing, this technology can extract helium from natural gas. However, because natural gas contains multiple gases, including methane, ethane, propane, nitrogen, and helium, the extraction and purification process for helium is complex and costly.

[0003] In existing natural gas processing technologies, flash evaporation is used to achieve multi-component separation, thereby improving the quality of natural gas and removing unwanted impurities. Flash evaporation involves introducing high-pressure saturated liquid into a relatively low-pressure flash tank, where a sudden pressure drop causes volatile components to rapidly convert into vapor, effectively separating major components such as methane, ethane, and propane.

[0004] However, due to the extremely low boiling point (-268.9°C) and small molecular size of helium, it accumulates in the gas phase during flash evaporation, making it difficult to effectively recover through conventional flash evaporation processes. This results in a large amount of helium being lost during flash evaporation, leading to a waste of resources. Summary of the Invention

[0005] The purpose of this application is to provide an online backflushing flash vapor recovery system and control method to extract helium after natural gas flash vaporization, ensuring efficient helium recovery and full utilization of resources.

[0006] To address the aforementioned technical problems, this application provides the following technical solutions:

[0007] The first aspect of this application provides an online backwash flash vapor recovery system, comprising:

[0008] A compression unit, the inlet of which is connected to the gas phase outlet of the flash tank;

[0009] The separation unit includes a filter line, an empty line, a permeate line, a non-permeate line, and an adsorption guide line. The filter line, from one end to the other, is sequentially connected to the outlet of the compression unit, a filter valve, the first end of the empty line, and the inlet of the membrane separation device. The empty line is connected to the empty valve. The permeate line, from one end to the other, is sequentially connected to the permeate outlet of the membrane separation device, the first end of the adsorption guide line, and an inlet valve. The adsorption guide line is connected to the adsorption guide valve. The non-permeate line, from one end to the other, is sequentially connected to the non-permeate outlet of the membrane separation device, the second end of the adsorption guide line, and the inlet of the adsorption device.

[0010] A backwashing unit includes a backwashing pipeline; the first end of the backwashing pipeline is located between the membrane separation device and the air inlet valve; the first end to the second end of the backwashing pipeline are sequentially connected to the permeate gas pipeline, the backwashing valve and the outlet of the gas storage tank, and the gas storage tank is used to store the backwashing gas;

[0011] The buffer unit includes an air inlet pipe; the first end to the second end of the air inlet pipe are sequentially connected to the second end of the permeate gas pipe and the inlet of the buffer tank, and the outlet of the adsorption device is connected to the inlet of the buffer tank.

[0012] In some modified embodiments of the first aspect of this application, the online backwash flash vapor recovery system further includes:

[0013] The monitoring unit includes a flow meter; the flow meter is connected to the air intake pipe, and the flow meter is used to detect the flow rate of the gas in the air intake pipe and generate a first signal;

[0014] The controller is signal-connected to the flow meter, the filter valve, the vent valve, the inlet valve, the adsorption guide valve, and the backwash valve; the flow meter can send the first signal to the controller, and the controller can control the on / off state of the filter valve, the vent valve, the inlet valve, the adsorption guide valve, and the backwash valve based on the first signal; the backwash pipeline is connected to a proportional regulating valve, the proportional regulating valve is signal-connected to the controller, and the controller can control the opening degree of the proportional regulating valve based on the first signal.

[0015] In some modified embodiments of the first aspect of this application, the monitoring unit further includes a pre-membrane pressure sensor and a post-membrane pressure sensor; the outlet of the compression unit is connected to the first end of the filter pipeline through the pre-membrane pressure sensor, the pre-membrane pressure sensor is used to detect the gas pressure before membrane separation treatment and generate a second signal; the post-membrane pressure sensor is connected to the inlet pipeline, the post-membrane pressure sensor is used to detect the gas pressure after membrane separation treatment and generate a third signal;

[0016] The controller is connected to the pre-membrane pressure sensor and the post-membrane pressure sensor respectively. The pre-membrane pressure sensor can send the second signal to the controller, and the post-membrane pressure sensor can send the third signal to the controller. The controller can calculate the differential pressure signal based on the second signal and the third signal. The controller can control the on / off state of the filter valve, the vent valve, the air inlet valve, the adsorption guide valve, and the backwash valve based on the differential pressure signal and the first signal.

[0017] In some embodiments, the backwashing unit further includes a gas storage pipeline; the first end of the gas storage pipeline is connected in sequence to the outlet of the compression unit, the gas storage valve, the pressurization unit and the inlet of the gas storage tank, and the gas storage tank is equipped with a pressure gauge, which is used to detect the gas pressure in the gas storage tank and generate a fourth signal;

[0018] The controller is connected to the pressure gauge, which can send the fourth signal to the controller, and the controller can control the opening and closing state of the gas storage valve based on the fourth signal.

[0019] In some embodiments, there are multiple separation units connected in parallel; the controller can control at least one of the separation units' filter valve, vent valve, air inlet valve, adsorption guide valve, and backwash valve to be in a first state based on the first signal to achieve backwashing operation; the controller can also control at least one of the separation units' filter valve, vent valve, air inlet valve, adsorption guide valve, and backwash valve to be in a second state based on the first signal to achieve membrane separation processing operation.

[0020] In some embodiments, the adsorption guide tube is connected to a particulate matter sensor, which is used to detect the particulate matter concentration of the gas in the adsorption guide tube and generate a fifth signal.

[0021] The particulate matter sensor is connected to the controller via a signal connection. The particulate matter sensor can send the fifth signal to the controller, and the controller can control the working state of the adsorption guide valve based on the first signal and the fifth signal.

[0022] In some embodiments, the compression unit includes a first switching valve, a first compressor, a second switching valve, a second compressor, and a thermometer; the first switching valve is respectively connected to the gas phase outlet of the flash tank and the inlet of the first compressor; the second switching valve is respectively connected to the gas phase outlet of the flash tank and the inlet of the second compressor; the outlets of the first compressor and the second compressor are both connected to the thermometer, and the thermometer is connected to the first end of the filter pipeline;

[0023] The thermometer is connected to the controller via a signal. The thermometer is used to detect the temperature of the compressed gas and generate a sixth signal. The thermometer can send the sixth signal to the controller, and the controller can control the first switching valve and the second switching valve to open selectively based on the sixth signal.

[0024] A second aspect of this application provides a control method for an online backwash flash vapor recovery system, implemented based on the aforementioned online backwash flash vapor recovery system, comprising:

[0025] The flash vapor is subjected to membrane separation treatment to obtain the actual permeate flow rate after the membrane separation treatment.

[0026] Compare the actual permeate flow rate with the preset permeate flow rate;

[0027] If the actual permeate flow rate is greater than or equal to the preset permeate flow rate, the current membrane separation process is maintained; if the actual permeate flow rate is less than the preset permeate flow rate, an online backwashing operation is performed, and the waste gas generated by the online backwashing operation is discharged from the recovery system.

[0028] After the online backwashing operation is completed, the flash vapor is subjected to the first stage of membrane separation treatment, and the gas after the first stage of membrane separation treatment is subjected to adsorption treatment.

[0029] After the membrane separation process in the first stage is completed, the flash vapor is subjected to the membrane separation process in the second stage, and the gas after the membrane separation process in the second stage is stored in the buffer unit of the recovery system. The permeate gas in the membrane separation process in the first stage and the permeate gas in the membrane separation process in the second stage have different flow directions.

[0030] In some modified embodiments of the second aspect of this application, the online backwashing operation includes multiple consecutive backwashing steps, each of which has a different pressure and / or flow rate of backwash gas.

[0031] In some embodiments, the method of performing online backwashing if the actual permeate flow rate is less than the preset permeate flow rate includes:

[0032] Obtain the actual pressure difference of the current membrane separation process;

[0033] Compare the actual pressure difference with the preset pressure difference;

[0034] If the actual pressure difference is less than the preset pressure difference, maintain the current membrane separation process; if the actual pressure difference is greater than or equal to the preset pressure difference, perform the online backwashing process.

[0035] Compared with existing technologies, the online backwash flash vapor recovery system provided in this application pressurizes the gas phase of the flash vapor through a compression unit to improve the separation efficiency of helium and reduce the loss of helium in the traditional flash evaporation process.

[0036] The flow meter detects the gas flow rate in the intake pipe and generates a first signal. Based on the first signal from the flow meter, the controller automatically adjusts the opening and closing status of each valve, thus realizing the automated operation of the system.

[0037] During normal membrane separation operation, the controller controls the filter valve and air inlet valve to open, and the vent valve, adsorption guide valve and backwash valve to close. The gas compressed by the compression unit is processed by the membrane separation device and then enters the buffer tank to ensure efficient helium recovery and stable system operation.

[0038] When backwashing is required, the controller closes the filter valve, air inlet valve, and adsorption guide valve, and opens the vent valve and backwash valve. The gas in the storage tank is discharged from the vent pipeline through the permeate outlet of the membrane separator, thus preventing the waste gas after backwashing from contaminating the gas in the recovery system.

[0039] After backwashing is completed, the controller opens the filter valve and adsorption guide valve, and closes the vent valve, air inlet valve and backwash valve to perform the first stage of membrane separation. The gas enters the adsorption device through the adsorption guide pipeline for adsorption treatment, removing the pollutants remaining in the membrane separation device after backwashing, and ensuring the separation effect of the subsequent membrane separation device.

[0040] After the first stage of membrane separation is completed, the controller controls the opening and closing status of each valve to proceed with the second stage of membrane separation (i.e., normal membrane separation).

[0041] The online backwash flash vapor recovery system of this application achieves automated online backwashing of the membrane separation unit through the coordinated operation of the compression unit, membrane separation device, backwashing unit, buffer unit, monitoring unit, and controller. It also removes residual contaminants after backwashing, ensuring high purity and efficient recovery of helium within the system. The entire system operates automatically via the controller, improving overall efficiency. Attached Figure Description

[0042] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, with the same or corresponding reference numerals denoteing the same or corresponding parts, wherein:

[0043] Figure 1 A schematic diagram of the online backwash flash vapor recovery system of this application is shown.

[0044] Figure 2 The schematic diagram illustrates the structure of the separation unit, buffer unit, and monitoring unit of the online backwash flash vapor recovery system of this application.

[0045] Explanation of icon numbers:

[0046] 1. Compression unit; 11. First switching valve; 12. First compressor; 13. Second switching valve; 14. Second compressor; 15. Thermometer; 2. Separation unit; 21. Filter line; 22. Exhaust line; 23. Permeate line; 24. Non-permeate line; 25. Adsorption guide line; 26. Filter valve; 27. Membrane separator; 28. Exhaust valve; 29. ​​Inlet valve; 210. Adsorption guide valve; 211. Adsorption device; 212. Particulate matter sensor; 3. Backwash unit; 31. Backwash line; 32. Backwash valve; 33. Gas storage tank; 34. Proportional regulating valve; 35. Gas storage line; 36. Gas storage valve; 37. Pressurization unit; 4. Buffer unit; 41. Inlet line; 42. Buffer tank; 5. Monitoring unit; 51. Flow meter; 52. Pre-membrane pressure sensor; 53. Post-membrane pressure sensor; 6. Flash tank. Detailed Implementation

[0047] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0048] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application shall have the ordinary meaning as understood by one of ordinary skill in the art to which this application pertains.

[0049] Example 1

[0050] like Figure 1 and Figure 2 As shown, Embodiment 1 of this application provides an online backwash flash vapor recovery system, comprising:

[0051] Compression unit 1, the inlet of which is connected to the gas phase outlet of flash tank 6;

[0052] Separation unit 2 includes a filter pipe 21, an exhaust pipe 22, a permeate gas pipe 23, a non-permeate gas pipe 24, and an adsorption guide pipe 25. The filter pipe 21 is connected from one end to the other to the outlet of the compression unit 1, a filter valve 26, the first end of the exhaust pipe 22, and the inlet of the membrane separation device 27. The exhaust pipe 22 is connected to an exhaust valve 28. The permeate gas pipe 23 is connected from one end to the other to the permeate gas outlet of the membrane separation device 27, the first end of the adsorption guide pipe 25, and an inlet valve 29. The adsorption guide pipe 25 is connected to an adsorption guide valve 210. The non-permeate gas pipe 24 is connected from one end to the other to the non-permeate gas outlet of the membrane separation device 27, the second end of the adsorption guide pipe 25, and the inlet of the adsorption device 211.

[0053] The backwashing unit 3 includes a backwashing pipeline 31; the first end of the backwashing pipeline 31 is located between the membrane separation device 27 and the air inlet valve 29; the first end to the second end of the backwashing pipeline 31 are sequentially connected to the outlet of the permeate gas pipeline 23, the backwashing valve 32 and the gas storage tank 33, and the gas storage tank 33 is used to store the backwashing gas.

[0054] In some embodiments, the online backflushing flash vapor recovery system further includes;

[0055] The buffer unit 4 includes an air inlet pipe 41; the first end to the second end of the air inlet pipe 41 are sequentially connected to the second end of the permeate gas pipe 23 and the inlet of the buffer tank 42, and the outlet of the adsorption device 211 is connected to the inlet of the buffer tank 42.

[0056] The monitoring unit 5 includes a flow meter 51; the flow meter 51 is connected to the air intake pipe 41, and the flow meter 51 is used to detect the flow rate of the gas in the air intake pipe 41 and generate a first signal.

[0057] The controller is signal-connected to the flow meter 51, the filter valve 26, the vent valve 28, the air inlet valve 29, the adsorption guide valve 210, and the backwash valve 32. The flow meter 51 can send the first signal to the controller, and the controller can control the on / off state of the filter valve 26, the vent valve 28, the air inlet valve 29, the adsorption guide valve 210, and the backwash valve 32 based on the first signal. The backwash pipeline 31 is connected to the proportional regulating valve 34, and the proportional regulating valve 34 is signal-connected to the controller. The controller can control the opening degree of the proportional regulating valve 34 based on the first signal.

[0058] Specifically, flash tank 6 is used to flash-process the mixed gas, separating the fuel gas from the helium gas by changing the temperature and pressure conditions. The gas phase outlet of flash tank 6 can be sealed to compression unit 1 through a pipeline to ensure that the gas does not leak.

[0059] Compression unit 1 is used to compress the gaseous flash vapor discharged from flash tank 6 to increase the gas pressure and concentration, facilitating subsequent separation and processing. The inlet of compression unit 1 is connected to the gaseous outlet of flash tank 6 via a sealed pipeline to ensure no gas leakage during transmission. The flash vapor enters compression unit 1 from the gaseous outlet of flash tank 6, is compressed to the required pressure level within compression unit 1, and then delivered to the first end of filter pipeline 21 of separation unit 2. This ensures that the gas entering separation unit 2 has sufficient pressure, which is beneficial for improving separation efficiency and effectiveness. Compression unit 1 can be a centrifugal compressor or a reciprocating compressor, etc.

[0060] Separation unit 2 is used for membrane separation of compressed flash vapor, separating permeate gas and non-permeate gas. Membrane separation device 27, through its selective permeation characteristics, can effectively separate different components in flash vapor to produce permeate gas and non-permeate gas, wherein the permeate gas is helium and the non-permeate gas is fuel gas. The membrane of membrane separation device 27 can be a polymer membrane (e.g., polyimide or polydimethylsiloxane), an inorganic membrane, or a mixed matrix membrane, etc. Filter valve 26 is installed near the first end of filter line 21 to quickly control the gas flow direction when needed. Inlet valve 29 controls the outflow of permeate gas, ensuring that it can smoothly enter buffer unit 4. Exhaust valve 28 controls the discharge of waste gas generated during backwashing out of the recovery system. Adsorption guide valve 210 controls the flow direction of permeate gas, ensuring that the permeate gas has different flow directions at different membrane treatment stages.

[0061] The backwashing unit 3 is used to backwash the membrane separation unit 27 to remove impurities accumulated on and inside the membrane, thereby extending the membrane's service life and maintaining its efficient operation. The backwashing process is achieved using cleaning gas (such as nitrogen or air) stored in the gas storage tank 33. The gas storage tank 33 stores the cleaning gas required for backwashing; the cleaning gas needs to have a certain pressure to effectively remove impurities from the membrane surface and interior, ensuring the effectiveness of the backwashing. The backwashing valve 32 is controlled by a controller to activate the backwashing process when needed.

[0062] Buffer unit 4 is used to temporarily store the separated permeate gas and balance the system pressure to ensure the stable operation of the entire system. Buffer tank 42 is used to store the permeate gas, ensuring that the gas pressure within the system remains stable. Connecting the outlet of adsorption device 211 to the inlet of buffer tank 42 allows the gas after adsorption treatment to also enter buffer tank 42, making the overall structure more compact.

[0063] Monitoring unit 5 is used to monitor the gas flow rate in the intake pipe 41 in real time and provide feedback signals to the controller. Flow meter 51 detects the gas flow rate and sends a first signal to the controller, which adjusts the opening and closing status of each valve according to the signal. Flow meter 51 can be a thermal mass flow meter 51 or an ultrasonic flow meter 51, etc.

[0064] The controller receives feedback signals from monitoring unit 5 and controls the opening and closing states of each valve to achieve automated system operation. The controller and monitoring unit 5 together form a closed-loop control system. Monitoring unit 5 provides real-time feedback, and the controller adjusts based on the first feedback signal, forming a continuously optimizing cycle. The controller analyzes the received data according to preset algorithms and logic rules. If the flow rate exceeds the set range, it indicates that the membrane has accumulated a large amount of impurities, affecting separation efficiency. In this case, the controller will initiate a backwashing procedure; otherwise, the controller will maintain the current membrane separation operation. The controller can be a programmable logic controller (PLC) or a distributed control system, etc.

[0065] like Figure 1 As shown, in some embodiments, the proportional control valve 34 is located between the outlet of the gas storage tank 33 and the membrane separator 27. The proportional control valve 34 is used to adjust the opening degree according to the controller's instructions, thereby controlling the flow rate and pressure of the backwash gas. By precisely adjusting the flow rate and pressure of the backwash gas, effective cleaning of the membrane separator 27 can be ensured, and the service life of the membrane can be extended. The proportional control valve 34 can be a solenoid valve or an electric control valve, etc.

[0066] The valves in this application can be selected from solenoid valves or electric regulating valves, etc.

[0067] Compared with the prior art, the online backwash flash vapor recovery system provided in this application pressurizes the gas phase of the flash vapor through the compression unit 1 to improve the separation efficiency of helium and reduce the loss of helium in the traditional flash evaporation process.

[0068] The flow meter 51 detects the gas flow rate in the intake pipe 41 and generates a first signal. Based on the first signal from the flow meter 51, the controller automatically adjusts the opening and closing status of each valve, thereby realizing the automated operation of the system.

[0069] During normal membrane separation operation, the controller controls the filter valve 26 and the inlet valve 29 to open, and the vent valve 28, the adsorption guide valve 210 and the backwash valve 32 to close. The gas compressed by the compression unit 1 is processed by the membrane separation device 27 and then enters the buffer tank 42 to ensure efficient helium recovery and stable system operation.

[0070] When backwashing is required, the controller closes the filter valve 26, the air inlet valve 29 and the adsorption guide valve 210, and opens the vent valve 28 and the backwash valve 32. The gas in the gas storage tank 33 is discharged from the vent pipe 22 through the permeate outlet of the membrane separator 27, so as to avoid the waste gas after backwashing from polluting the gas in the recovery system.

[0071] After backwashing is completed, the controller opens the filter valve 26 and the adsorption guide valve 210, and closes the vent valve 28, the air inlet valve 29 and the backwash valve 32 to perform the first stage of membrane separation. The gas enters the adsorption device 211 through the adsorption guide pipeline 25 for adsorption treatment, removing the pollutants remaining in the membrane separation device 27 after backwashing, and ensuring the separation effect of the subsequent membrane separation device 27.

[0072] After the first stage of membrane separation treatment is completed (for example, the first stage of membrane separation treatment can be preset for a time, such as 3-5 minutes), the controller controls the opening and closing status of each valve to carry out the second stage of membrane separation treatment (i.e., normal membrane separation treatment).

[0073] The online backwash flash vapor recovery system of this application achieves automated online backwashing of the membrane separation unit 27 through the coordinated operation of the compression unit 1, membrane separation unit 27, backwashing unit 3, buffer unit 4, monitoring unit 5, and controller. It also removes residual contaminants after backwashing, ensuring high purity and efficient recovery of helium within the system. The entire system operates automatically via the controller, improving overall efficiency.

[0074] like Figure 1 and Figure 2As shown, in some embodiments, the monitoring unit 5 further includes a pre-membrane pressure sensor 52 and a post-membrane pressure sensor 53; the outlet of the compression unit 1 is connected to the first end of the filter pipeline 21 through the pre-membrane pressure sensor 52, which is used to detect the gas pressure before membrane separation and generate a second signal; the post-membrane pressure sensor 53 is connected to the air inlet pipeline 41, which is used to detect the gas pressure after membrane separation and generate a third signal;

[0075] The controller is connected to the pre-membrane pressure sensor 52 and the post-membrane pressure sensor 53 respectively. The pre-membrane pressure sensor 52 can send the second signal to the controller, and the post-membrane pressure sensor 53 can send the third signal to the controller. The controller can calculate the differential pressure signal based on the second signal and the third signal. The controller can control the opening and closing states of the filter valve 26, the vent valve 28, the air inlet valve 29, the adsorption guide valve 210, and the backwash valve 32 based on the differential pressure signal and the first signal.

[0076] Specifically, compression unit 1 compresses the gaseous flash vapor discharged from flash tank 6 to the required pressure level. The controller calculates the differential pressure signal based on the second and third signals. When the differential pressure measured by the pre-membrane pressure sensor 52 and the post-membrane pressure sensor 53 is large, it indicates that there may be high resistance inside the membrane separation device 27, meaning that a large amount of impurities or contaminants have accumulated on or inside the membrane, increasing the difficulty for gas to pass through the membrane. When the differential pressure measured by the pre-membrane pressure sensor 52 and the post-membrane pressure sensor 53 is small, it indicates that the membrane separation device 27 is operating well, there is no significant accumulation of impurities on or inside the membrane, and the gas can pass through the membrane smoothly, achieving the expected separation effect.

[0077] When both the differential pressure signal and the flow rate signal indicate a decline in system performance (i.e., high differential pressure and low flow rate), the controller initiates the backwashing procedure. If at least one signal (differential pressure signal or the first signal) indicates normal system performance (i.e., low differential pressure or normal flow rate), the controller maintains the current separation operation of the membrane separation unit 27 to ensure efficient and stable system operation.

[0078] like Figure 1 As shown, in some embodiments, the backwashing unit 3 further includes an air storage pipeline 35; the first end to the second end of the air storage pipeline 35 are sequentially connected to the outlet of the compression unit 1, the air storage valve 36, the pressurization unit 37 and the inlet of the air storage tank 33, and the air storage tank 33 is equipped with a pressure gauge (not shown in the figure), which is used to detect the gas pressure in the air storage tank 33 and generate a fourth signal;

[0079] The controller is connected to the pressure gauge, and the pressure gauge can send the fourth signal to the controller. The controller can control the opening and closing state of the gas storage valve 36 based on the fourth signal.

[0080] Specifically, the two ends of the gas storage pipeline 35 are connected to the outlet of the compression unit 1 and the inlet of the gas storage tank 33, respectively. The gas storage pipeline 35 is used to send the gas compressed by the compression unit 1 into the gas storage tank 33 through the gas storage valve 36 and the pressurization unit 37 for subsequent backwashing; that is, backwashing is performed using flash vapor from the recovery system, making the overall structure more compact. The pressurization unit 37 is used to further pressurize the gas compressed by the compression unit 1 to meet the pressure requirements of subsequent backwashing. The pressurization unit 37 can be a centrifugal compressor or a reciprocating compressor, etc. A pressure gauge is used to detect the gas pressure inside the gas storage tank 33 and generate a fourth signal to send to the controller.

[0081] When the gas pressure in the gas storage tank 33 is lower than the preset range, the controller receives a fourth signal from the pressure gauge. The controller then controls the gas storage valve 36 to open, allowing the gas compressed by the compression unit 1 to enter the pressurization unit 37 through the gas storage pipeline 35. The pressurization unit 37 further increases the gas pressure to reach the high pressure level required by the gas storage tank 33. After passing through the pressurization unit 37, the gas enters the gas storage tank 33, and the pressure inside the gas storage tank 33 gradually increases. When the gas pressure in the gas storage tank 33 reaches the set value, the controller closes the gas storage valve 36. During the backwash gas storage process, the controller can control the simultaneous membrane separation or backwashing operation. The gas storage valve 36 can be a solenoid valve or an electric regulating valve, etc.

[0082] like Figure 1 As shown, in some embodiments, there are multiple separation units 2 (not shown in the figure), and the multiple separation units 2 are connected in parallel; the controller can control at least one of the separation unit 2's filter valve 26, vent valve 28, air inlet valve 29, adsorption guide valve 210, and backwash valve 32 to be in a first state based on the first signal to realize backwashing operation; the controller can also control at least one of the separation unit 2's filter valve 26, vent valve 28, air inlet valve 29, adsorption guide valve 210, and backwash valve 32 to be in a second state based on the first signal to realize membrane separation processing operation.

[0083] Specifically, by setting up redundant separation units 2, the recovery system can simultaneously perform membrane separation and backwashing operations, ensuring that other separation units 2 can still operate normally while some of them are being backwashed. The number of separation units 2 can be designed according to actual process requirements; for example, there can be two or four separation units 2. Taking four separation units 2 as an example, two separation units 2 can be used for separation operations at a time. When the controller determines that the current two separation units 2 need backwashing, it can perform backwashing on the current two separation units 2, while the controller controls the other two separation units 2 to perform membrane separation processing, thereby improving the efficiency of helium recovery.

[0084] like Figure 2 As shown, in some embodiments, the adsorption guide tube 25 is connected to a particulate sensor 212, which is used to detect the particulate concentration of the gas in the adsorption guide tube 25 and generate a fifth signal.

[0085] The particulate sensor 212 is connected to the controller via a signal connection. The particulate sensor 212 can send the fifth signal to the controller, and the controller can control the working state of the adsorption guide valve 210 based on the first signal and the fifth signal.

[0086] Specifically, the particulate matter sensor 212 can be a high-precision particulate matter sensor 212 with a fast response speed, such as a laser scattering particulate matter sensor 212, to ensure accurate detection of particulate matter concentration.

[0087] When the controller determines that the current operation is a membrane separation process, if the particulate matter concentration is high, the controller determines that there are many particles in the permeate gas and that adsorption treatment is required before entering buffer unit 4 to ensure the purity of the helium gas finally entering buffer unit 4. If the particulate matter concentration is low, the controller determines that there are few particles in the permeate gas, and the controller initiates the membrane separation process and directly sends the gas to buffer unit 4 to improve separation efficiency.

[0088] like Figure 1 As shown, in some embodiments, the compression unit 1 includes a first switching valve 11, a first compressor 12, a second switching valve 13, a second compressor 14, and a thermometer 15; the first switching valve 11 is respectively connected to the gas phase outlet of the flash tank 6 and the inlet of the first compressor 12; the second switching valve 13 is respectively connected to the gas phase outlet of the flash tank 6 and the inlet of the second compressor 14; the outlets of the first compressor 12 and the second compressor 14 are both connected to the thermometer 15, and the thermometer 15 is connected to the first end of the filter pipeline 21;

[0089] The thermometer 15 is connected to the controller via a signal. The thermometer 15 is used to detect the temperature of the compressed gas and generate a sixth signal. The thermometer 15 can send the sixth signal to the controller, and the controller can control the first switching valve 11 and the second switching valve 13 to open selectively based on the sixth signal.

[0090] Specifically, at system startup, the first switching valve 11 can be opened by default, the first compressor 12 can be selected for compression, and the second switching valve 13 can be closed. Thermometer 15 can monitor the temperature of the compressed gas in real time and send a sixth signal to the controller. If the temperature of the compressed gas is detected to be within a preset range (e.g., below a set high-temperature threshold), the controller keeps the first switching valve 11 open and continues to use the first compressor 12 for compression. If the temperature of the compressed gas is detected to exceed the preset range (e.g., equal to or higher than the set high-temperature threshold), the controller determines that the first compressor 12 may be overloaded or malfunctioning, and needs to switch to the backup second compressor 14. By monitoring the temperature of the compressed gas in real time and dynamically adjusting the selection and operation of the compressor according to the actual situation, the efficient operation and stability of the system are ensured.

[0091] The first compressor 12 can be a centrifugal compressor or a reciprocating compressor, etc. The second compressor 14 can be a centrifugal compressor or a reciprocating compressor, etc. The first switching valve 11 can be a solenoid valve or an electric regulating valve, etc. The second switching valve 13 can be a solenoid valve or an electric regulating valve, etc.

[0092] Example 2

[0093] Embodiment 2 of this application provides a control method for an online backflushing flash vapor recovery system, including:

[0094] The flash vapor is subjected to membrane separation treatment to obtain the actual permeate flow rate after the membrane separation treatment.

[0095] Compare the actual permeate flow rate with the preset permeate flow rate;

[0096] If the actual permeate flow rate is greater than or equal to the preset permeate flow rate, the current membrane separation process is maintained; if the actual permeate flow rate is less than the preset permeate flow rate, an online backwashing operation is performed, and the waste gas generated by the online backwashing operation is discharged from the recovery system.

[0097] After the online backwashing operation is completed, the flash vapor is subjected to the first stage of membrane separation treatment, and the gas after the first stage of membrane separation treatment is subjected to adsorption treatment.

[0098] After the membrane separation process in the first stage is completed, the flash vapor is subjected to the membrane separation process in the second stage, and the gas after the membrane separation process in the second stage is stored in the buffer unit 4 of the recovery system. The permeate gas from the membrane separation process in the first stage and the permeate gas from the membrane separation process in the second stage have different flow directions.

[0099] Specifically, compression unit 1 compresses the gaseous flash vapor discharged from flash tank 6 to the required pressure level. Membrane separation unit 27 performs membrane separation treatment on the compressed gas, and flow meter 51 detects the actual permeate flow rate after the membrane separation treatment and generates a first signal to send to the controller. The controller receives and compares the actual permeate flow rate with the preset permeate flow rate.

[0100] When the actual permeate flow rate is greater than or equal to the preset permeate flow rate, the controller maintains the current membrane separation operation and continues the membrane separation process. When the actual permeate flow rate is less than the preset permeate flow rate, the controller initiates an online backwashing operation to remove impurities and contaminants from the membrane separation unit 27.

[0101] After the backwashing operation is completed, the controller restarts the membrane separation process, entering the first stage of membrane separation. The permeate after the first stage of membrane separation is guided into the adsorption unit 211 for further purification to ensure gas purity. The purified gas then enters the buffer unit 4 for storage.

[0102] After the first-stage membrane separation process is completed, the controller switches to the second-stage membrane separation process. The permeate after the second-stage membrane separation process is directly stored in the buffer unit 4 of the recovery system for subsequent use or further processing.

[0103] The control method of the online backwash flash vapor recovery system disclosed in this application realizes online automated backwashing of the membrane separation unit 27, and can remove residual contaminants after backwashing of the membrane separation unit 27, ensuring high purity and efficient recovery of helium in the system. The entire system is automated through a controller, improving overall work efficiency.

[0104] In some embodiments, the online backwashing operation includes multiple consecutive backwashing steps, each with a different pressure and / or flow rate of the backwash gas.

[0105] Specifically, online backwashing operations include two, three, four, or even more consecutive backwashing steps. For example, an online backwashing operation may include three consecutive steps: low-pressure, low-flow backwashing (e.g., 0.5 bar, 10 L / min), medium-pressure, medium-flow backwashing (e.g., 2 bar, 50 L / min), and high-pressure, high-flow backwashing (e.g., 5 bar, 100 L / min). The controller automatically switches to the next backwashing step based on a preset time interval or detected pressure changes. The controller precisely controls the pressure and flow rate of the backwash gas in each step by adjusting the opening of the proportional control valve. Through multiple consecutive backwashing steps, impurities and contaminants in the membrane separation unit can be effectively removed, ensuring efficient system operation and high-purity helium recovery.

[0106] In some embodiments, the method of performing online backwashing if the actual permeate flow rate is less than the preset permeate flow rate includes:

[0107] Obtain the actual pressure difference of the current membrane separation process;

[0108] Compare the actual pressure difference with the preset pressure difference;

[0109] If the actual pressure difference is less than the preset pressure difference, maintain the current membrane separation process; if the actual pressure difference is greater than or equal to the preset pressure difference, perform the online backwashing process.

[0110] Specifically, the pressure at the front end of the membrane separation unit 27 is detected by the pre-membrane pressure sensor 52, and a corresponding signal is sent to the controller. The pressure at the rear end of the membrane separation unit 27 is detected by the post-membrane pressure sensor 53, and a corresponding signal is sent to the controller. The controller calculates the differential pressure signal based on the pressure signals from the pre-membrane pressure sensor 52 and the post-membrane pressure sensor 53, and determines whether the system needs backwashing by combining the flow rate signal. When both the differential pressure signal and the flow rate signal indicate a decline in system performance (i.e., large differential pressure and low flow rate), the controller initiates the backwashing procedure. If at least one signal (differential pressure signal or the first signal) indicates normal system performance (i.e., small differential pressure or normal flow rate), the controller maintains the current separation operation of the membrane separation unit 27 to ensure efficient and stable system operation.

[0111] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An online backwash flash vapor recovery system, characterized in that, include: A compression unit, the inlet of which is connected to the gas phase outlet of the flash tank; The separation unit includes a filter line, an empty line, a permeate line, a non-permeate line, and an adsorption guide line. The filter line, from one end to the other, is sequentially connected to the outlet of the compression unit, a filter valve, the first end of the empty line, and the inlet of the membrane separation device. The empty line is connected to the empty valve. The permeate line, from one end to the other, is sequentially connected to the permeate outlet of the membrane separation device, the first end of the adsorption guide line, and an inlet valve. The adsorption guide line is connected to the adsorption guide valve. The non-permeate line, from one end to the other, is sequentially connected to the non-permeate outlet of the membrane separation device, the second end of the adsorption guide line, and the inlet of the adsorption device. A backwashing unit includes a backwashing pipeline; the first end of the backwashing pipeline is located between the membrane separation device and the air inlet valve; the first end to the second end of the backwashing pipeline are sequentially connected to the permeate gas pipeline, the backwashing valve and the outlet of the gas storage tank, and the gas storage tank is used to store the backwashing gas; A buffer unit includes an air inlet pipe; the first end to the second end of the air inlet pipe are sequentially connected to the second end of the permeate gas pipe and the inlet of the buffer tank, and the outlet of the adsorption device is connected to the inlet of the buffer tank. The adsorption guide tube is connected to a particulate matter sensor, which is used to detect the particulate matter concentration of the gas in the adsorption guide tube and generate a fifth signal.

2. The online backwash flash vapor recovery system according to claim 1, characterized in that, Also includes: The monitoring unit includes a flow meter; the flow meter is connected to the air intake pipe, and the flow meter is used to detect the flow rate of the gas in the air intake pipe and generate a first signal; The controller is signal-connected to the flow meter, the filter valve, the vent valve, the inlet valve, the adsorption guide valve, and the backwash valve; the flow meter can send the first signal to the controller, and the controller can control the on / off state of the filter valve, the vent valve, the inlet valve, the adsorption guide valve, and the backwash valve based on the first signal; The backwash line is connected to a proportional control valve, which is signal-connected to the controller. The controller can control the opening degree of the proportional control valve based on the first signal.

3. The online backwash flash vapor recovery system according to claim 2, characterized in that, The monitoring unit further includes a pre-membrane pressure sensor and a post-membrane pressure sensor; the outlet of the compression unit is connected to the first end of the filter pipeline through the pre-membrane pressure sensor, which is used to detect the gas pressure before membrane separation and generate a second signal; the post-membrane pressure sensor is connected to the inlet pipeline, which is used to detect the gas pressure after membrane separation and generate a third signal. The controller is connected to the pre-membrane pressure sensor and the post-membrane pressure sensor respectively. The pre-membrane pressure sensor can send the second signal to the controller, and the post-membrane pressure sensor can send the third signal to the controller. The controller can calculate the differential pressure signal based on the second signal and the third signal. The controller can control the on / off state of the filter valve, the vent valve, the air inlet valve, the adsorption guide valve, and the backwash valve based on the differential pressure signal and the first signal.

4. The online backwash flash vapor recovery system according to claim 2, characterized in that, The backwashing unit also includes a gas storage pipeline; the first end of the gas storage pipeline is connected to the outlet of the compression unit, the gas storage valve, the pressurization unit and the inlet of the gas storage tank in sequence from the second end of the gas storage pipeline. The gas storage tank is equipped with a pressure gauge, which is used to detect the gas pressure in the gas storage tank and generate a fourth signal. The controller is connected to the pressure gauge, which can send the fourth signal to the controller, and the controller can control the opening and closing state of the gas storage valve based on the fourth signal.

5. The online backwash flash vapor recovery system according to claim 2, characterized in that, The separation unit comprises multiple units connected in parallel. The controller is capable of controlling at least one of the separation unit's filter valve, vent valve, air inlet valve, adsorption guide valve, and backwash valve to a first state based on the first signal to achieve backwashing operation. The controller is also capable of controlling at least one of the separation unit's filter valve, vent valve, air inlet valve, adsorption guide valve, and backwash valve to a second state based on the first signal to achieve membrane separation processing operation.

6. The online backwash flash vapor recovery system according to claim 2, characterized in that, The particulate sensor is connected to the controller via a signal, and the particulate sensor can send the fifth signal to the controller. The controller can control the working state of the adsorption guide valve based on the first signal and the fifth signal.

7. The online backwash flash vapor recovery system according to claim 2, characterized in that, The compression unit includes a first switching valve, a first compressor, a second switching valve, a second compressor, and a thermometer; the first switching valve is used to connect to the gas phase outlet of the flash tank and the inlet of the first compressor, respectively; the second switching valve is used to connect to the gas phase outlet of the flash tank and the inlet of the second compressor, respectively; the outlets of the first compressor and the second compressor are both connected to the thermometer, and the thermometer is connected to the first end of the filter pipeline; The thermometer is connected to the controller via a signal. The thermometer is used to detect the temperature of the compressed gas and generate a sixth signal. The thermometer can send the sixth signal to the controller, and the controller can control the first switching valve and the second switching valve to open selectively based on the sixth signal.

8. A control method for an online backwash flash vapor recovery system, implemented based on the online backwash flash vapor recovery system according to any one of claims 1-7, characterized in that, include: The flash vapor is subjected to membrane separation treatment to obtain the actual permeate flow rate after the membrane separation treatment. Compare the actual permeate flow rate with the preset permeate flow rate; If the actual permeate flow rate is greater than or equal to the preset permeate flow rate, maintain the current membrane separation process operation; If the actual permeate flow rate is less than the preset permeate flow rate, an online backwashing operation is performed, and the waste gas generated by the online backwashing operation is discharged from the recovery system. After the online backwashing operation is completed, the flash vapor is subjected to the first stage of membrane separation treatment, and the gas after the first stage of membrane separation treatment is subjected to adsorption treatment. After the membrane separation process in the first stage is completed, the flash vapor is subjected to the membrane separation process in the second stage, and the gas after the membrane separation process in the second stage is stored in the buffer unit of the recovery system. The permeate gas in the membrane separation process in the first stage and the permeate gas in the membrane separation process in the second stage have different flow directions.

9. The control method for the online backflushing flash vapor recovery system according to claim 8, characterized in that, The online backwashing operation includes multiple consecutive backwashing steps, each with a different pressure and / or flow rate of backwash gas.

10. The control method for the online backflushing flash vapor recovery system according to claim 8, characterized in that, The method for performing online backwashing if the actual permeate flow rate is less than the preset permeate flow rate includes: Obtain the actual pressure difference of the current membrane separation process; Compare the actual pressure difference with the preset pressure difference; If the actual pressure difference is less than the preset pressure difference, maintain the current membrane separation process; if the actual pressure difference is greater than or equal to the preset pressure difference, perform the online backwashing process.

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