Waste nanofiltration membrane cleaning detection and performance calibration device under brine system

Abstract

The utility model relates to a waste nanofiltration membrane cleaning detection and performance calibration device under a brine system. Relates to the field of waste nanofiltration membrane recovery treatment. Comprising a cleaning agent tank, an adjusting tank, a flushing water tank, a raw material liquid tank, a water feeding pump, a security filter, a high-pressure pump, a nanofiltration membrane shell and a weight sensor. After a nanofiltration membrane for refining underground brine reaches the service life, the retention rate of calcium and magnesium ions cannot meet the use requirement, but the retention rate of sulfate radicals is still high, and meanwhile, the retention rate of the nanofiltration membrane is influenced by blockage of calcium sulfate precipitates. The device can monitor the progress of cleaning the calcium sulfate precipitate by detecting the variable quantity of the weight of the waste nanofiltration membrane in the cleaning process, so that the cleaning efficiency is improved, and partial performance of the waste nanofiltration membrane is recovered. The device is a cleaning detection and performance calibration integrated device, and performance test calibration can be directly carried out after the waste nanofiltration membrane is cleaned.

Description

Technical Field

[0001] The utility model relates to the field of recycling and reuse of waste nanofiltration membranes, and particularly to a device for cleaning, detecting and performance calibration of waste nanofiltration membranes in a brine system. Background Technique

[0002] As a new type of separation membrane in membrane science, the nanofiltration membrane has been more and more widely used in water treatment engineering in the past decade or so due to its remarkable separation characteristics. According to different requirements, there are currently many different types of nanofiltration membranes. In the field of salt chemical industry, a nanofiltration membrane is currently in use, which is used to produce a sodium chloride solution with a higher purity from underground brine. The concentrated water with a higher content of calcium, magnesium and sulfate ions intercepted by it is discharged. In this process, the nanofiltration membrane has a risk of being blocked and fouled by calcium sulfate precipitates generated by the combination of calcium ions and sulfate ions. Due to the complex use environment, the designed service life of general nanofiltration membranes is about 4-5 years. When the nanofiltration membrane reaches the designed service life, it will be treated as solid waste, increasing the use cost. Although the interception rate of calcium and magnesium ions by the nanofiltration membrane drops significantly after reaching the designed service life, it still has a high interception effect on sulfate ions, so it still has the value of utilization. For example, in a seawater desalination system, the cleaned and calibrated waste nanofiltration membrane can be used for the pretreatment of seawater to reduce the concentration of sulfate ions in seawater. Chinese Patent CN210544424U discloses a device for standardizing the test of nanofiltration membranes in a brine system, which can realize the cleaning and performance standardization test of nanofiltration membranes. For waste nanofiltration membranes in a brine system, due to the different degrees of blockage inside different waste nanofiltration membranes, this device cannot monitor the cleaning situation of waste nanofiltration membranes in real time. Content of the Utility Model

[0003] The utility model discloses for the first time a device for cleaning, detecting and performance calibration of waste nanofiltration membranes in a brine system. This device can monitor in real time the weight change of waste nanofiltration membranes blocked by precipitates such as calcium sulfate during the cleaning process, maximize the recovery of the performance of waste nanofiltration membranes with different degrees of blockage, and test their performance under different raw liquid and different pressures. According to the performance differences, the waste nanofiltration membranes are used reasonably.

[0004] The device for cleaning, detecting and performance calibration of waste nanofiltration membranes under the described brine system includes a cleaning agent tank for holding the cleaning agent, an adjustment tank for holding the diluted cleaning agent, a flushing water tank for holding clean water, a raw material liquid tank for holding the raw material liquid used to calibrate the waste nanofiltration membrane, a water supply pump for supplying the cleaning agent, clean water and raw material liquid, a security filter for filtering macromolecular impurities, a high-pressure pump for pressurizing the raw material liquid, a nanofiltration membrane housing for holding the waste nanofiltration membrane, a weight sensor for measuring weight, etc. The cleaning agent tank is connected to the adjustment tank through a pipeline connected to an electric control valve. The adjustment tank, the flushing water tank and the raw material liquid tank are respectively connected to the main water supply pipeline through pipelines connected to electric on-off valves. The main water supply pipeline is connected to the water supply pump. The outlet of the water supply pump is connected to the security filter through a pipeline. An influent water flowmeter and an electric on-off valve are provided on the pipeline between the water supply pump and the security filter. The security filter is connected to the high-pressure pump through a pipeline. The high-pressure pump is connected to the water inlet of the nanofiltration membrane housing through a water supply pipeline. A bypass is provided between the inlet and the outlet of the high-pressure pump. A water supply pressure gauge for displaying the water supply pressure is provided behind the high-pressure pump. An electric on-off valve is provided on the bypass. An electric on-off valve for the water inlet of the membrane housing is provided at the water inlet of the membrane housing. The electric on-off valve for the water inlet of the membrane housing is connected to the membrane housing by a hose. At the water production outlet of the membrane housing, a membrane housing water production on-off valve, a membrane housing water production sampling valve and a membrane housing water production flowmeter are successively provided. The membrane housing water production on-off valve is connected to the water production outlet of the membrane housing by a hose. At the concentrated water outlet of the membrane housing, a membrane housing concentrated water on-off valve, a membrane housing concentrated water sampling valve and a membrane housing concentrated water flowmeter are successively provided. The membrane housing concentrated water on-off valve is connected to the concentrated water outlet of the membrane housing by a hose. Weight sensors are provided below both ends of the membrane housing. The weight sensors are installed on the support members. The weight sensors are used to detect in real time the weight change of the nanofiltration membrane in the nanofiltration membrane housing during the cleaning process. The support members of the nanofiltration membrane housing are in contact with the ground and are used to support the nanofiltration membrane housing and the weight sensors.

[0005] Multiple nanofiltration membrane housings are arranged horizontally in parallel and connected to the water supply pipeline. The produced water and concentrated water of all nanofiltration membrane housings are respectively converged into the produced water main pipeline and the concentrated water main pipeline. The produced water main pipeline is connected to the raw material liquid tank and the adjustment tank. The concentrated water main pipeline is connected to the raw material liquid tank and the adjustment tank. A produced water main pipeline on-off valve and a produced water discharge valve are provided on the produced water main pipeline. A concentrated water main pipeline on-off valve and a concentrated water discharge valve are provided on the concentrated water main pipeline. The produced water main pipeline is respectively connected to the raw material liquid tank and the adjustment tank through a produced water main pipeline raw material liquid tank branch on-off valve and a produced water main pipeline adjustment tank branch on-off valve. The concentrated water main pipeline is respectively connected to the raw material liquid tank and the adjustment tank through a concentrated water main pipeline raw material liquid tank branch on-off valve and a produced water main pipeline adjustment tank branch on-off valve. There is at least one cleaning agent tank, adjustment tank, flushing water tank and raw material liquid tank. Among them, the number of cleaning agent tanks, adjustment tanks and raw material liquid tanks can be increased according to the specific needs of users.

[0006] Advantages of the present utility model: By using the device of the present utility model, the progress of cleaning calcium sulfate precipitation can be monitored by detecting the change in the weight of the waste nanofiltration membrane during the cleaning process, the cleaning efficiency can be improved, and some performance of the waste nanofiltration membrane can be restored. This device is an integrated device for cleaning detection and performance calibration, and can directly perform performance test calibration after the cleaning of the waste nanofiltration membrane is completed. The device for cleaning detection and performance calibration of waste nanofiltration membranes in a brine system according to the present utility model can detect the cleaning progress of the waste nanofiltration membrane by real-time detecting the weight change rate of the waste nanofiltration membrane, so as to more accurately control the cleaning duration, improve the cleaning efficiency, and is applicable to the cleaning and performance calibration work of a large number of waste nanofiltration membranes. Description of the Drawings

[0007] Figure 1 It is a specific connection schematic diagram of the device for cleaning detection and performance calibration of waste nanofiltration membranes for refining underground brine in the embodiment of the present utility model. Detailed Embodiment

[0008] The present utility model will be further described below in conjunction with the drawings and embodiments.

[0009] The device for cleaning detection and performance calibration of waste nanofiltration membranes for refining underground brine according to the present utility model is an integrated device for cleaning detection and performance calibration of waste nanofiltration membranes.

[0010] The device mainly includes a cleaning agent tank 101 for containing cleaning agents, an adjustment tank 103 for containing cleaning agents with a certain concentration, a flushing water tank 105 for containing clear water to flush the device and the waste nanofiltration membrane, and a raw material liquid tank 107 for storing calibration raw material liquid. The cleaning agent tank 101 is connected to the adjustment tank 103 through a pipeline provided with an electric control valve 102 for the concentration of the cleaning agent. The adjustment tank 103, the flushing water tank 105 and the raw material liquid tank 107 are respectively connected to the main water supply pipeline 109 through an outlet valve 104 of the adjustment tank, an outlet valve 106 of the flushing water tank and an outlet valve 108 of the raw material liquid. Two branches are separated from the clear water pipeline and are respectively connected to the adjustment tank 103 and the flushing water tank 105 through a clear water valve 114 of the adjustment tank and a clear water valve 115 of the flushing water tank to adjust the concentration of the cleaning agent and supplement the flushing water.

[0011] Among them, there is at least one raw material liquid tank 107, cleaning agent tank 101, adjustment tank 103, and flushing water tank 105. The number of tanks of the raw material liquid tank 107, cleaning agent tank 101, and adjustment tank 103 can be increased according to requirements. The main water supply pipeline is connected to the water supply pump 201 that provides power. The water supply pump 201 is connected to the security filter 204 that filters out macromolecular impurities in the liquid through a pipeline. There is at least one security filter 204, and its quantity is determined according to the rated flow of the water supply pump 201. A flowmeter 202 for displaying the water supply flow and a water supply electric control valve 202 for adjusting the water supply flow are successively arranged between the water supply pump 201 and the security filter 204. The security filter 204 is connected to the high-pressure pump 207 that increases the water supply pressure. The high-pressure pump 207 is connected to the water inlet of the nanofiltration membrane housing 303 through a water supply pipeline. The high-pressure pump 207 is provided with an electric switch valve 205 in front of the high-pressure pump and a high-pressure pump bypass with an electric switch valve 206 for the high-pressure pump bypass. A water supply pressure gauge 208 for displaying the water supply pressure is arranged behind the high-pressure pump 207. An electric switch valve 301 for the water inlet of the nanofiltration membrane housing is arranged at the water inlet of the nanofiltration membrane housing 303. The electric switch valve 301 for the water inlet of the membrane housing is connected to the membrane housing 303 through a hose. At the water production port of the nanofiltration membrane housing, a membrane housing water production switch valve 307, a membrane housing water production sampling valve 311, and a membrane housing water production flowmeter 308 are successively arranged. The membrane housing water production switch valve 307 is connected to the water production port of the membrane housing 303 through a hose; at the concentrated water port, a membrane housing concentrated water switch valve 304, a membrane housing concentrated water sampling valve 310, and a membrane housing concentrated water flowmeter 305 are successively arranged. The membrane housing concentrated water switch valve 304 is connected to the concentrated water port of the membrane housing 303 through a hose. The weight sensor 302 is installed on a support member (not shown in the figure) and is used to detect in real time the weight change of the nanofiltration membrane in the nanofiltration membrane housing 303 during the cleaning process. The support member of the nanofiltration membrane housing is in contact with the ground and is used to support the nanofiltration membrane housing 303 and the weight sensor 302.

[0012] Multiple nanofiltration membrane housings 303 are arranged in parallel horizontally. The water production and concentrated water of all nanofiltration membrane housings are respectively converged into the water production main pipe 313 and the concentrated water main pipe 312. A water production total flow control valve 309 and a water production discharge valve 315 are arranged on the water production main pipe. A concentrated water total flow control valve 306 and a concentrated water discharge valve 314 are arranged on the concentrated water main pipe. The water production main pipe 313 is respectively connected to the raw material liquid tank 107 and the adjustment tank 103 through a water production main pipe raw material liquid tank branch pipe switch valve 113 and a water production main pipe adjustment tank branch pipe switch valve 111. The concentrated water main pipe 312 is respectively connected to the raw material liquid tank 107 and the adjustment tank 103 through a concentrated water main pipe raw material liquid tank branch pipe switch valve 112 and a water production main pipe adjustment tank branch pipe switch valve 110.

[0013] In addition, the used nanofiltration membrane cleaning detection and performance calibration device for refining underground brine of the present utility model further includes a control unit, which is electrically connected to various pumps, valves, sensors and other devices described below to achieve automatic control. Example 1

[0014] Refer to the following Figure 1 The operating steps of the detection, flushing, cleaning and calibration of a device integrating cleaning detection and performance calibration of waste nanofiltration membranes are described in detail:

[0015] (1) Test the performance of the waste nanofiltration membrane. All valves in the system are closed. Open the raw liquid tank outlet electric valve 108, the high-pressure pump front electric switch valve 205, the membrane shell water inlet electric switch valve 301, the membrane shell water production switch valve 307, the membrane shell concentrated water switch valve 304, the total concentrated water flow regulating valve 306, the concentrated water main pipe raw liquid tank branch switch valve 112, the total produced water flow regulating valve 309, the produced water main pipe raw liquid tank branch switch valve 113, start the feed water pump 201, slowly open the feed water electric regulating valve 203, start the high-pressure pump, and use the total concentrated water flow regulating valve 306 to assist in controlling the feed water pressure at a certain value. Record the produced water flow and concentrated water flow of the membrane shell 303 under this pressure. Sampling is performed through the concentrated water sampling valve 310 and the produced water sampling valve 311, and the ion concentrations in the produced water and concentrated water are detected and the ion retention rate is calculated. Stop the high-pressure pump 206 and the water supply pump 201 in sequence, close the water supply electric regulating valve 203, the electric switch valve 205 in front of the high-pressure pump, the raw liquid tank outlet electric valve 108, the membrane shell water inlet electric switch valve 301, the membrane shell water production switch valve 307, the membrane shell concentrated water switch valve 304, the total concentrated water flow regulating valve 306, the concentrated water main pipe raw liquid tank branch pipe switch valve 112, the total water production flow regulating valve 309, and the water production main pipe raw liquid tank branch pipe switch valve 113.

[0016] (2) Rinse the waste nanofiltration membrane. All valves in the system are in the closed state. Open the flushing water tank outlet valve 106, the high-pressure pump bypass switch valve 207, the membrane shell water inlet electric switch valve 301, the membrane shell concentrated water switch valve 304, the produced water discharge valve 315, and the concentrated water discharge valve 314 in sequence. Start the water supply pump 201, adjust the water supply electric regulating valve 203 to control the water supply flow, and flush the waste nanofiltration membrane. The flushing water is discharged through the concentrated water discharge valve 314 and the produced water discharge valve 315. After flushing, close the flushing water tank outlet electric valve 106 and the water supply pump 201. After draining the flushing water (after flushing, the residual flushing water in the device can be discharged from the switch valve set in the lower pipeline of the device, which is not shown in the attached figure), close the concentrated water discharge valve 314 and the produced water discharge valve 315.

[0017] (3) Clean the used nanofiltration membrane. After cleaning, open the cleaning agent concentration regulating valve 102 to configure the cleaning agent. After configuration is completed, close the cleaning agent concentration regulating valve 102. Open the regulating tank outlet electric valve 104, the production water main pipe regulating tank branch pipe switch valve 111, and the concentrated water main pipe regulating tank branch pipe switch valve 110. Start the feed water pump 201 to clean the used nanofiltration membrane. Record the difference between the gravity sensor value at the beginning of cleaning and the weight of the used nanofiltration membrane, and record the change of the weight sensor value over time until the gravity sensor value stabilizes and there is no obvious decrease in a short period. Then, close the cleaning agent tank outlet electric valve 108 and the feed water pump 201, and close all other valves. The above steps can be repeated to clean with different types of cleaning agents. Flushing is required before and after each cleaning step.

[0018] The reference standard index Ω for qualified cleaning is as follows:

[0019]

[0020] G1 is the weight before cleaning, G2 is the weight after cleaning, and g is the standard weight of the used nanofiltration membrane of this model when leaving the factory.

[0021] (4) Calibrate the performance of the used nanofiltration membrane after cleaning. All valves in the system are in the closed state. Open the raw material liquid tank outlet electric valve 108, the feed water electric regulating valve 203, the high-pressure pump front electric switch valve 205, the membrane housing inlet water electric switch valve 301, the membrane housing concentrated water switch valve 304, the membrane housing production water switch valve 307, the total concentrated water flow regulating valve 306, the concentrated water main pipe raw material liquid tank branch pipe switch valve 112, the total production water flow regulating valve 309, and the production water main pipe raw material liquid tank branch pipe switch valve 113 in sequence. Start the feed water pump 201 and the high-pressure pump 209, adjust the frequency of the high-pressure pump 209, and use the total concentrated water flow regulating valve 306 to assist in controlling the feed water pressure. Record the production water flow and concentrated water flow at different pressures. Take samples through the concentrated water sampling valve 310 and the production water sampling valve 311 to detect the sulfate ion concentration in the production water and concentrated water. After completion, close all pumps and valves. Example 2

[0022] In an embodiment of the application of a device for cleaning, detecting, and calibrating the performance of used nanofiltration membranes for refining underground brine, select 6 used nanofiltration membranes of the same batch with a factory standard weight of 12 kg, record the current weight, and perform cleaning simultaneously. Record the weight change trend, eliminate the influence of interference factors in the weight detection process, and draw a weight change trend graph. Calibrate the used nanofiltration membrane after cleaning and record the ion rejection rate at different pressures.

[0023]

[0024] Based on the data summarized after the cleaning, testing, and calibration experiments on these 6 selected waste nanofiltration membranes of the same batch with a factory standard weight of 12 kg according to this embodiment, the following conclusions can be drawn:

[0025] (1) The cleaning conditions of the waste nanofiltration membranes numbered 1, 2, 3, and 4 are good, and the standard index Ω is greater than 0.8; the cleaning conditions of the waste nanofiltration membranes numbered 5 and 6 are unqualified. Among them, the weight change of the waste nanofiltration membrane numbered 5 is not obvious after 0.5 hours of cleaning. After adjusting the concentration of the cleaning agent, the cleaning effect is better. After cleaning for 2.5 hours, the weight change is relatively not obvious, and the blockage situation is still relatively serious. If continued cleaning is time-consuming and laborious, the choice is to abandon the cleaning.

[0026] (2) After the cleaning and calibration of the waste nanofiltration membranes numbered 1, 2, 3, and 4, their performance has been restored to a certain extent. The performance of the waste nanofiltration membrane numbered 6 has basically no change before and after cleaning and is far lower than that of other waste nanofiltration membranes, proving that its internal damage is serious and it has no value for reuse.

Claims

1. A device for cleaning, detecting and performance calibration of waste nanofiltration membranes in a brine system, characterized in that It includes a cleaning agent tank, an adjustment tank, a flushing water tank, a raw material liquid tank, a feed water pump, a security filter, a high-pressure pump, a nanofiltration membrane housing, and a weight sensor. The cleaning agent tank is connected to the adjustment tank through a pipeline after being connected to an electric control valve. The adjustment tank, the flushing water tank, and the raw material liquid tank are respectively connected to the main water supply pipeline through pipelines after being connected to electric on-off valves. The main water supply pipeline is connected to the feed water pump. The outlet of the feed water pump is connected to the security filter through a pipeline. A feed water flowmeter and an electric on-off valve are provided on the pipeline between the feed water pump and the security filter. The security filter is connected to the high-pressure pump through a pipeline. The high-pressure pump is connected to the water inlet of the nanofiltration membrane housing through a water supply pipeline. A bypass is provided between the inlet and the outlet of the high-pressure pump, and an electric on-off valve is provided on the bypass. An electric on-off valve for the water inlet of the membrane housing is provided at the water inlet of the membrane housing. The electric on-off valve for the water inlet of the membrane housing is connected to the membrane housing by a hose. A membrane housing water production on-off valve, a membrane housing water production sampling valve, and a membrane housing water production flowmeter are successively provided at the water production outlet of the membrane housing. The membrane housing water production on-off valve is connected to the water production outlet of the membrane housing by a hose. A membrane housing concentrated water on-off valve, a membrane housing concentrated water sampling valve, and a membrane housing concentrated water flowmeter are successively provided at the concentrated water outlet of the membrane housing. The membrane housing concentrated water on-off valve is connected to the concentrated water outlet of the membrane housing by a hose. Weight sensors are provided below both ends of the membrane housing, and the weight sensors are installed on the support members.

2. The cleaning detection and performance calibration device for waste nanofiltration membranes under the brine system according to claim 1, wherein The nanofiltration membrane housings are arranged in multiple horizontal parallel connections and are connected to the water supply pipeline.

3. The device for cleaning, detecting and performance calibration of waste nanofiltration membranes in a brine system according to claim 1, wherein, The weight sensor is used to detect in real time the weight change of the nanofiltration membrane in the membrane housing during the cleaning process. The support member of the membrane housing is in contact with the ground and is used to support the membrane housing of the nanofiltration membrane and the weight sensor.

4. The device for cleaning, detecting and performance calibration of waste nanofiltration membranes under a brine system according to claim 1 or 2, characterized in that The water production and concentrated water of all nanofiltration membrane housings are respectively converged into a water production main pipe and a concentrated water main pipe. The water production main pipe is connected to the raw material liquid tank and the adjustment tank, and the concentrated water main pipe is connected to the raw material liquid tank and the adjustment tank.

5. The cleaning detection and performance calibration device for waste nanofiltration membranes under the brine system according to claim 1, characterized in that There is at least one cleaning agent tank, adjustment tank, flushing water tank, and raw material liquid tank respectively.

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