A device system and method for observing particle motion in continuous cross-flow filtration

Abstract

The present invention relates to an observation device system and method for particle motion in continuous cross-flow filtration. By designing a flat membrane cross-flow filtration device, ideal cross-flow filtration can be achieved, thereby being consistent with the ideal flow conditions in a theoretical model. At the same time, non-invasive observation of particle motion can be achieved, avoiding the influence of a lens on the cross-flow in invasive observation. The particle motion observation using the observation device system is simple and easy to operate, has efficient data processing, intuitive experimental recording results, low measurement cost, and can comprehensively obtain particle dynamics information such as particle displacement and velocity.

Description

Technical Field

[0001] The present invention relates to the field of reactor device measurement technology, and in particular to an observation device system and method for particle movement in continuous cross-flow filtration. Background Art

[0002] Since the concept of membrane reactors was proposed in the 1970s, they have gradually been widely used in biotechnology and chemical technology. For separation membranes, they can be formed into single membrane modules, such as cross-flow filtration membrane modules or dead-end filtration membrane modules, or placed in traditional reactors, such as stirred reactors, to form reaction-separation coupled membrane reactors. Single membrane modules have been widely used in various fields such as wastewater treatment and biological separation, while reaction-separation coupled membrane reactors have also gradually begun to be used in continuous chemical synthesis processes such as catalytic hydrogenation, but large-scale industrial application has not yet been achieved.

[0003] Membrane fouling has always been a key factor restricting the scale-up of membrane reactors and the long-term stable and continuous operation of membrane modules. In addition to macroscopically examining the effects of operating parameters such as feed rate on membrane permeation flux, the membrane fouling process can be visualized with the help of direct observation technology. Fane et al. (Tanudjaja HJ, Pee W, Fane AG, et al. Effect of spacer and crossflow velocity on the critical flux of bidisperse suspensions in microfiltration [J]. Journal of Membrane Science, 2016, 513: 101-107.) observed membrane fouling in filtration systems such as bacteria and particles. However, the membranes used in their experiments were required to be transparent membranes or transparent membranes in a wet state, and ultimately were limited to qualitatively describing the movement of bacteria and particles, and no large amounts of data were obtained to support the analysis of membrane fouling dynamics.

[0004] Chen et al. (Lorenzen S, Ye Y, Chen V, et al. Direct observation of fouling phenomenon during cross-flow filtration: Influence of particle surface charge [J]. Journal of Membrane Science, 2016: 546-558.) investigated the formation process of the membrane fouling layer near the polyvinylidene fluoride membrane, but they still remained at the level of macroscopic movement of pollutants. Due to the low resolution and system turbidity, they were unable to obtain the clear outline and actual movement trajectory of single particles.

[0005] Therefore, in order to realize the measurement and analysis of the dynamics of membrane fouling microparticles, it is necessary to establish a stable and easy-to-operate experimental device system and method, which can obtain the particle motion trajectory under a large number of different operating parameters, analyze the particle force and critical operating parameters, and thus pre-adjust the process operating parameters, inhibit membrane fouling, extend the service life of the membrane assembly, and improve the continuous operation efficiency and stability of the filtration separation and reaction-separation coupling system. Summary of the Invention

[0006] The purpose of the present invention is to provide a device system and method for observing particle motion in continuous cross-flow filtration, which can realize the observation and recording of particle motion near the membrane or in any flow cross section under relatively ideal cross-flow filtration conditions.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides an observation device system for particle movement in continuous cross-flow filtration, the observation device system comprising a quantitative feeding unit, a flat membrane cross-flow filtration unit, and a quantitative permeate discharge unit connected in sequence along the material flow direction; and further comprising a non-invasive direct observation device for photographing and analyzing the particle movement in the flat membrane cross-flow filtration unit;

[0009] The flat membrane cross-flow filtration unit includes a flat membrane cross-flow filtration device, which includes a material inlet section, a material inlet flow development section, a membrane filtration main section, and a filtrate outlet flow development section arranged in sequence along the material flow direction, wherein a flat filter membrane is arranged in the membrane filtration main section; the flat membrane cross-flow filtration device is provided with a material inlet, a permeate outlet, and a filtrate outlet, and the filtrate outlet is connected to a filtrate discharge device;

[0010] The non-invasive direct observation device includes a strong light source, a high-speed camera, a telecentric lens located at the front end of the high-speed camera, and a data recording system connected to the high-speed camera, wherein the strong light source and the telecentric lens are located on both sides of the target cross section of the observed particle motion and are placed opposite to each other;

[0011] The quantitative permeate discharging unit is connected to a data recording system.

[0012] The observation device system provided by the present invention can achieve ideal cross-flow filtration by designing a flat membrane cross-flow filtration device, avoiding the fluctuation of the flow on the membrane in the general cross-flow filtration device, so that it can be consistent with the ideal flow conditions in the theoretical model, and at the same time, it can realize non-invasive observation of particle movement, avoiding the influence of the lens on the cross-flow in invasive observation; in addition, the use of a telecentric lens and back lighting can achieve clear observation of the particle contour, avoiding the erroneous judgment of the particle outer contour by side lighting and the optical distortion caused by ordinary industrial lenses; among them, the setting of the filtrate outlet flow development section can not only eliminate the backflow of the outlet flow, but also enable the operating parameters such as the inlet flow rate and the permeation rate to be transformed into multiple combinations to obtain a large sample data volume to support particle dynamics calculations.

[0013] Preferably, the filtrate discharge device includes a filtrate storage tank.

[0014] Preferably, the housing of the flat membrane cross-flow filtration device is made of transparent material.

[0015] Preferably, the quantitative feeding unit comprises a raw material stirring tank, a feeding peristaltic pump and a pulse damper which are sequentially connected along the material flow direction, and the pulse damper is connected to the material inlet.

[0016] Preferably, a stirring device is provided in the raw material stirring tank.

[0017] Preferably, the stirring device includes a stirring motor and a stirring paddle.

[0018] Preferably, the raw material stirring tank, the feed peristaltic pump, the pulse damper and the connecting pipe used for connecting the material inlet are made of glass.

[0019] The use of glass connecting tubes to transport solid-liquid mixtures reduces the friction resistance of particles inside the pipes and avoids the deposition of particles in pipes made of traditional materials such as stainless steel pipes and silicone hoses, thereby achieving uniform particle concentration throughout the entire process.

[0020] Preferably, the quantitative permeate discharge unit comprises a buffer device, a pressure gauge, a discharge peristaltic pump and a permeate storage device connected in sequence along the material flow direction. The permeate storage device is placed on an online balance, and the online balance is connected to a data recording system.

[0021] Preferably, the buffer device is connected to the permeate outlet.

[0022] Preferably, the buffer device comprises a buffer bottle.

[0023] Preferably, the permeate storage device comprises a permeate storage tank.

[0024] The strong light source of the present invention is placed relative to the telecentric lens, that is, back lighting. The strong light source and the telecentric lens are respectively located on both sides of the target observation section, and their vertical heights can be adjusted according to imaging quality.

[0025] In a second aspect, the present invention provides a method for observing particle motion in continuous cross-flow filtration, wherein the observation is performed using the device system for observing particle motion in continuous cross-flow filtration described in the first aspect, and the method comprises the following steps:

[0026] The solid-liquid mixture is fed into a flat membrane cross-flow filtration device. The permeate is discharged after the solid-liquid mixture flows smoothly. At the same time, the permeate mass is recorded in real time using a data recording system. A high-speed camera is used to capture images of the particle movement in the target section and transmit them to the data recording system for image post-processing and calculation.

[0027] The method for observing particle motion in continuous cross-flow filtration provided by the present invention is simple and easy to operate, has stable cyclic operation, efficient data processing, intuitive experimental recording results, low measurement cost, and can comprehensively obtain particle dynamics information such as particle displacement and velocity.

[0028] Preferably, the liquid phase in the solid-liquid mixture comprises deionized water.

[0029] Preferably, the solid phase in the solid-liquid mixture includes solid particles or colloidal particles.

[0030] Preferably, the solid particles comprise polystyrene or silicon dioxide.

[0031] Preferably, the magnification of the telecentric lens used for shooting is ≥1 times, for example, it can be 1 times, 2 times or 3 times, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0032] It should be noted that the solid-liquid mixture described in the present invention flows smoothly, which means that the solid-liquid two-phase flow conforms to an ideal cross-current flow mode, and there is no fluid backflow and fluctuation.

[0033] It should be noted that the feed peristaltic pump flow rate and the permeate outlet flow rate of the present invention can be equal or unequal, that is, various feed rate and permeate rate combination experimental conditions can be set to obtain a large data sample size that can calculate the particle dynamics as accurately as possible.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The observation device system provided by the present invention can achieve ideal cross-flow filtration by designing a flat membrane cross-flow filtration device, avoiding the fluctuation of the flow on the membrane in the general cross-flow filtration device, so as to be consistent with the ideal flow conditions in the theoretical model, and at the same time can realize non-invasive observation of particle movement, avoiding the influence of the lens on the cross-flow in invasive observation; in addition, the use of a telecentric lens and back lighting can achieve clear observation of the particle contour, avoiding the erroneous judgment of the particle outer contour by side lighting and the optical distortion caused by ordinary industrial lenses; wherein, the setting of the filtrate outlet flow development section can not only eliminate the backflow of the outlet flow, but also enable the operating parameters such as the inlet flow rate and the permeation rate to be changed into a variety of combinations to obtain a large sample data volume to support the particle dynamics calculation; the use of the observation device system for particle motion observation is simple and easy to operate, the cycle operation is stable, the data processing is efficient, the experimental record results are intuitive, the measurement cost is low, and comprehensive particle dynamics information such as particle displacement and velocity can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 1 is a schematic structural diagram of a device system for observing particle movement in continuous cross-flow filtration provided in Example 1 of the present invention;

[0037] Figure 2 Schematic diagram of the structure of the flat membrane cross-flow filtration device provided in Example 1 of the present invention;

[0038] Figure 3 This is a photograph of the particle motion trajectory provided by Example 1 of the present invention;

[0039] Figure 4 This is a schematic diagram of the change in particle movement speed provided by Example 1 of the present invention;

[0040] Among them: 1, flat membrane cross-flow filtration device; 2, material inlet section; 3, material inlet flow development section; 4, membrane filtration main section; 5, filtrate outlet flow development section; 6, flat filter membrane; 7, material inlet; 8, permeate outlet; 9, filtrate outlet; 10, filtrate storage tank; 11, strong light source; 12, high-speed camera; 13, telecentric lens; 14, data recording system; 15, raw material stirring tank; 16, feed peristaltic pump; 17, pulse damper; 18, buffer bottle; 19, pressure gauge; 20, discharge peristaltic pump; 21, permeate storage tank; 22, online balance. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0042] Example 1

[0043] This embodiment provides an observation device system for particle movement in continuous cross-flow filtration, such as Figure 1 As shown, the observation device system includes a quantitative feeding unit, a flat membrane cross-flow filtration unit, and a quantitative permeate discharge unit connected in sequence along the material flow direction; and also includes a non-invasive direct observation device, which is used to capture and analyze the particle movement in the flat membrane cross-flow filtration unit;

[0044] The flat membrane cross-flow filtration unit includes a flat membrane cross-flow filtration device 1, such as Figure 2 As shown, the flat membrane cross-flow filtration device 1 includes a material inlet section 2, a material inlet flow development section 3, a membrane filtration main section 4, and a filtrate outlet flow development section 5, which are arranged in sequence along the material flow direction. The membrane filtration main section 4 is 60 mm wide and 210 mm long, and a flat filter membrane 6 with a width of 60 mm and a length of 210 mm is arranged inside. The shell of the flat membrane cross-flow filtration device 1 is made of a transparent material; the flat membrane cross-flow filtration device 1 is provided with a material inlet 7, a permeate outlet 8, and a filtrate outlet 9, and the filtrate outlet 9 is connected to a filtrate storage tank 10;

[0045] The non-invasive direct observation device includes a strong light source 11, a high-speed camera 12, a telecentric lens 13 located at the front end of the high-speed camera 12, and a data recording system 14 connected to the high-speed camera 12. The strong light source 11 and the telecentric lens 13 are respectively located on both sides of the target cross section of the observed particle motion and are placed opposite each other.

[0046] The quantitative feeding unit includes a raw material stirring tank 15, a feeding peristaltic pump 16, and a pulse damper 17 connected in sequence along the material flow direction. The pulse damper 17 is connected to the material inlet 7. A stirring motor and a stirring paddle are provided in the raw material stirring tank 15. The connecting pipe connecting the raw material stirring tank 15, the feeding peristaltic pump 16, the pulse damper 17, and the material inlet 7 is made of glass.

[0047] The quantitative permeate discharge unit includes a buffer bottle 18, a pressure gauge 19, a discharge peristaltic pump 20 and a permeate storage tank 21 connected in sequence along the material flow direction. The permeate storage tank 21 is placed on an online balance 22, and the online balance 22 is connected to the data recording system 14; the buffer bottle 18 is connected to the permeate outlet 8.

[0048] An observation device system is used to observe particle movement during continuous cross-flow filtration, and the observation method includes the following steps:

[0049] A solid-liquid mixture with a solid content of 0.3‰ obtained by mixing deionized water and silica particles with an average particle size of 50 μm was fed into a flat membrane cross-flow filtration device 1 at a feed rate of 300 mL / min. After the solid-liquid mixture flowed smoothly, the permeate was discharged, and the permeate flux was 200 mL / min. At the same time, the permeate mass was recorded in real time using a data recording system 14, and an image of the particle movement in the target cross section was captured using a high-speed camera 12 and transmitted to the data recording system 14 for image post-processing and calculation. The magnification of the telecentric lens 13 used for the shooting was 10 times.

[0050] The trajectory of the particles is shown in the following figure: Figure 3 As shown in (a), (b), (c), and (d), the phenomenon of particle clustering and migration can be observed; the images were taken using Image J software. Figure 2 The relative displacement of particles is obtained and the particle velocity is further calculated, such as Figure 4 As shown in the figure, the particle motion speed of the 6 particle trajectories obtained is obtained, and the particle acceleration can be further obtained to analyze the particle force.

[0051] Example 2

[0052] This embodiment provides an observation device system for particle movement in continuous cross-flow filtration, and the observation device system is the same as that in Example 1.

[0053] An observation device system is used to observe particle movement during continuous cross-flow filtration, and the observation method includes the following steps:

[0054] A solid-liquid mixture with a solid content of 0.3‰ obtained by mixing deionized water and silica particles with an average particle size of 100 μm was fed into a flat membrane cross-flow filtration device 1 at a feed rate of 100 mL / min. After the solid-liquid mixture flowed smoothly, the permeate was discharged at a permeate flux of 200 mL / min. At the same time, the permeate mass was recorded in real time using a data recording system 14, and an image of the particle movement in the target cross section was captured using a high-speed camera 12 and transmitted to the data recording system 14 for image post-processing and calculation. The magnification of the telecentric lens 13 used for the capture was 5 times.

[0055] Image J software was used to Figure 2 The relative displacement of the particles is obtained by quantization, and the particle velocity is calculated. The particle acceleration can be further obtained to analyze the force on the particles.

[0056] In summary, the observation device system provided by the present invention can achieve ideal cross-flow filtration by designing a flat membrane cross-flow filtration device, avoiding the fluctuation of the flow on the membrane in the general cross-flow filtration device, so that it can be consistent with the ideal flow conditions in the theoretical model, and at the same time, it can realize non-invasive observation of particle movement, avoiding the influence of the lens on the cross-flow in invasive observation; in addition, the use of telecentric lens and back lighting can achieve clear observation of particle contours, avoiding the erroneous judgment of the particle outer contour by side lighting, and the optical distortion caused by ordinary industrial lenses; wherein, the setting of the filtrate outlet flow development section can not only eliminate the backflow of the outlet flow, but also enable the operating parameters such as the inlet flow rate and the permeation rate to be changed into a variety of combinations to obtain a large sample data volume to support particle dynamics calculations; the use of the observation device system for particle motion observation is simple and easy to operate, the cycle operation is stable, the data processing is efficient, the experimental recording results are intuitive, the measurement cost is low, and comprehensive particle dynamics information such as particle displacement and velocity can be obtained.

[0057] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A device system for observing particle movement in continuous cross-flow filtration, characterized in that: The observation device system includes a quantitative feeding unit, a flat membrane cross-flow filtration unit, and a quantitative permeate discharge unit connected in sequence along the material flow direction; and also includes a non-invasive direct observation device, which is used to photograph and analyze the particle movement in the flat membrane cross-flow filtration unit; The flat membrane cross-flow filtration unit includes a flat membrane cross-flow filtration device, which includes a material inlet section, a material inlet flow development section, a membrane filtration main section, and a filtrate outlet flow development section arranged in sequence along the material flow direction, wherein a flat filter membrane is arranged in the membrane filtration main section; the flat membrane cross-flow filtration device is provided with a material inlet, a permeate outlet, and a filtrate outlet, and the filtrate outlet is connected to a filtrate discharge device; The non-invasive direct observation device includes a strong light source, a high-speed camera, a telecentric lens located at the front end of the high-speed camera, and a data recording system connected to the high-speed camera, wherein the strong light source and the telecentric lens are located on both sides of the target cross section of the observed particle motion and are placed opposite to each other; The quantitative permeate discharging unit is connected to a data recording system.

2. The observation device system according to claim 1, characterized in that The shell of the flat membrane cross-flow filtration device is made of transparent material.

3. The observation device system according to claim 1 or 2, characterized in that: The quantitative feeding unit includes a raw material stirring tank, a feeding peristaltic pump and a pulse damper which are sequentially connected along the material flow direction, and the pulse damper is connected to the material inlet.

4. The observation device system according to claim 3, characterized in that A stirring device is provided in the raw material stirring tank.

5. The observation device system according to claim 4, characterized in that The stirring device includes a stirring motor and a stirring paddle.

6. The observation device system according to claim 3, characterized in that The raw material stirring tank, the feed peristaltic pump, the pulse damper and the connecting pipe used for connecting the material inlet are made of glass.

7. The observation device system according to claim 1, characterized in that The quantitative permeate discharge unit includes a buffer device, a pressure gauge, a peristaltic discharge pump and a permeate storage device connected in sequence along the material flow direction. The permeate storage device is placed on an online balance, and the online balance is connected to a data recording system.

8. The observation device system according to claim 7, characterized in that The buffer device is connected to the permeate outlet.

9. A method for observing particle motion in continuous cross-flow filtration, characterized in that: The particle movement observation device system in continuous cross-flow filtration according to any one of claims 1 to 8 is used for observation, and the observation method comprises the following steps: The solid-liquid mixture is fed into a flat membrane cross-flow filtration device. The permeate is discharged after the solid-liquid mixture flows smoothly. At the same time, the permeate mass is recorded in real time using a data recording system. A high-speed camera is used to capture images of the particle movement in the target section and transmit them to the data recording system for image post-processing and calculation.

10. The observation method according to claim 9, characterized in that: The liquid phase in the solid-liquid mixture includes deionized water.

11. The observation method according to claim 9, characterized in that: The solid phase in the solid-liquid mixture includes solid particles or colloidal particles.

12. The observation method according to claim 11, characterized in that: The solid particles include polystyrene or silicon dioxide.

13. The observation method according to claim 9, characterized in that: The magnification of the telecentric lens used for the shooting is ≥1 times.

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