Device for testing water conservancy distribution of electrodialysis partition plate

Abstract

The utility model relates to a water conservancy distribution testing device for electrodialysis clapboards, and belongs to the field of electrodialysis clapboards. The device comprises a first water tank, a second water tank, a test frame, a test clamping plate, a test PVC plate and a water pump, the first water tank and the second water tank are both arranged on the test frame, the test clamping plate and the test PVC plate are connected and are both fixed on the test frame, a partition plate to be detected is placed between the test clamping plate and the test PVC plate, and the water pump is installed on the test frame. The device is reasonable in structural design, and is used for detecting the thickness uniformity and flatness of the partition plate so as to improve the membrane stack and interlayer water distribution uniformity and meet the use requirements.

Description

Technical Field

[0001] The utility model relates to a device, in particular to a water distribution testing device for an electrodialysis partition, and belongs to the field of electrodialysis partitions. Background Art

[0002] The global shortage of fresh water resources has led to the rapid development of membrane desalination technology to meet the industrial and household needs of clean water production. Electrodialysis technology is one of the membrane separation technologies that was developed earlier and has achieved significant industrial success. The principle is that under the action of electric field force, cations can pass through cation exchange membranes, and anions can pass through anion exchange membranes to achieve the migration of electrolyte ions, and finally achieve the concentration or desalination of substances. This technology has the advantages of simple equipment assembly process, convenient operation, and great adaptability. Therefore, electrodialysis technology has been increasingly used in wastewater treatment, food industry, and special separation. Factors affecting the performance of electrodialysis include the structure and performance of ion exchange membranes, the material and structure of water distribution baffles, the shape of membrane stacks, operating conditions, and feed characteristics.

[0003] As a core component, the electrodialysis separator consists of a separator frame and a separator mesh. The actual picture and structural schematic diagram of the separator are shown in the figure below. The separator is mainly used to maintain the distance between membranes, create solution channels and promote solution circulation. The internal guide net is usually a mesh woven structure. The separator not only supports the anion and cation exchange membrane, but also delays the impact of the violent turbulence of the salt solution on the anion and cation exchange membrane, prolongs its service life and reduces scaling. At the same time, the existence of the separator has a good stirring effect, and a relatively high limiting current density can be obtained. The good flow state of the solution in the compartment can make the ions replace quickly to reduce the difference in ion transmission between the membrane phase and the solution phase, thereby inhibiting the concentration polarization phenomenon at the membrane-solution interface, thereby reducing the non-ohmic resistance of the device. At the same time, the material, thickness and geometry of the separator directly affect the ohmic resistance of the membrane stack. In addition, the presence of the electrodialysis separator will make the fluid more evenly distributed in each compartment of the electrodialyzer, thereby weakening the thickness of the boundary layer and thinning the stagnant layer, thereby strengthening the mass transfer process on the membrane surface and improving the mass transfer efficiency in the electrodialysis process.

[0004] However, unoptimized baffles may result in poor fluid dynamics, pressure loss, uneven distribution and reduced energy-saving potential, and may produce flow dead spots on the baffles and even solid deposits on the membrane. It can be seen that the selection of optimized baffles is crucial to electrodialysis technology. At the same time, the flow channel mesh of traditional baffles is usually made of non-conductive materials that cannot pass ions, such as polyvinyl chloride, polypropylene, etc. These woven meshes cover part of the ion exchange membrane area, preventing the transmission of ions from the solution to the membrane in this area, resulting in a smaller membrane area for ion transmission and an increase in the resistance of the membrane stack, which is called the baffle shadow effect. The existence of the shadow effect causes the ion flow path through the baffle mesh to be tortuous, that is, the current generated by the movement of ions flows in a tortuous manner. Therefore, the traditional baffles widely used to maintain the membrane interval will seriously increase the resistance of the membrane stack due to the shadow effect and lose 30-40% of the output power. In addition, the weaving structure of the baffle flow channel makes the mesh intersection tortuous and uneven, causing the solution to flow in a curved manner, thereby generating additional hydraulic friction and increasing the energy consumption of the water pump. Therefore, in order to reduce the resistance of the membrane stack and obtain high power output, the design of the partition is particularly critical.

[0005] The prior art is as follows:

[0006] (1) Use alternatives

[0007] The use of corrugated membranes and profiled membranes as alternatives to traditional separators has become the main method to limit the separator shadow effect and increase the power output of the membrane stack. Although the use of profiled membranes can reduce the ohmic resistance of the membrane stack by about 30% compared to traditional separators, it greatly limits the turbulence of the solution in the channel and introduces concentration polarization with more serious consequences. In this case, due to the huge increase in non-ohmic resistance, the total resistance of the membrane stack has not been significantly reduced, which makes the actual power density of the improved electrodialysis membrane stack still relatively low;

[0008] (2) CFD technology

[0009] Due to the inherently small and difficult to measure dimensions of the baffles, the effects of different spacer geometries on flow patterns are not easily measured experimentally, and advances in numerical performance have made computational fluid dynamics (CFD) techniques the primary means of understanding fluid flow in baffle-filled channels. Compared to the large number of numerical studies, only a few experimental studies can directly visualize and characterize flow patterns in feed-spacer-filled channels;

[0010] (3) Three-dimensional (3-D) numerical model

[0011] Three-dimensional (3-D) numerical models are designed to emphasize the effect of feed spacers on fluid dynamics and mass transfer in the feed spacer channels. For example, in spiral-wound reverse osmosis membrane modules, simplified cylindrical shapes are used to represent the spacer filaments in most numerical studies. However, microscopic observations of feed spacers show that the spacers used in commercial spiral-wound membrane modules have more irregular geometries with varying filament thicknesses;

[0012] (4) Particle Image Velocimetry (PIV)

[0013] Particle Image Velocimetry (PIV) is able to study the microscale flow distribution in the baffle-filled flow channels of membrane modules, but this experimental method has certain limitations in the channel thickness used, the applied linear flow rate, the spatial or inter-dimensional resolution, and the flow is not visualized.

[0014] Disadvantages of the existing technology: The current CFD model is designed with many assumptions and therefore has the following limitations: First, the unit method uses periodic boundary conditions for modeling, which ignores the flow of the fluid along the channel and the development of mass transfer. Due to the presence of the baffle mesh, the fluid flow condition will not be fully manifested until the fluid flows through 4-5 units; Second, it is assumed that the flow is stable. Although this assumption is reasonable for a relatively low Reynolds number, the flow of the fluid in the baffle will become unstable when the flow rate increases; Third, it is assumed that the physical properties of the fluid are constant and the number of parameters evaluated is relatively limited. Utility Model Content

[0015] The purpose of the utility model is to overcome the above-mentioned deficiencies in the prior art and to provide an electrodialysis partition water distribution testing device with a reasonable structural design for detecting the thickness uniformity and flatness of the partition to improve the uniformity of the membrane stack and the water distribution between layers.

[0016] The technical solution adopted by the utility model to solve the above-mentioned problem is: the electrodialysis partition water distribution test device includes water tank one, water tank two and a test frame, and the water tank one and water tank two are both placed on the test frame. It is characterized in that it also includes a test clamping plate, a test PVC plate and a water pump, the test clamping plate and the test PVC plate are connected and fixed on the test frame, the partition to be tested is placed between the test clamping plate and the test PVC plate, and the water pump is installed on the test frame.

[0017] Preferably, a water inlet float flowmeter is provided between the water pump and the test clamping plate of the utility model.

[0018] Preferably, the test clamping plate of the utility model has the same area as the test PVC plate.

[0019] Preferably, the test clamping plate and the test PVC plate of the utility model are both made of transparent acrylic plates.

[0020] Compared with the prior art, the utility model has the following advantages and effects: the overall structural design is reasonable, and the technology of the application scheme can be used to visualize the flow distribution state of the liquid in the partition, and the uniformity of the water distribution inside the partition can be detected in real time, and problems can be discovered immediately, which is convenient for researchers to carry out targeted design optimization immediately, greatly improving the timeliness of the partition performance analysis, which is of great significance for the partition optimization research; improving the uniformity of water distribution between membrane stacks and layers. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the utility model.

[0022] Figure: Water tank one 1, water tank two 2, test frame 3, test clamping plate 4, test PVC board 5, water pump 6. DETAILED DESCRIPTION

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and through examples. The following examples are provided to explain the present invention, but the present invention is not limited to the following examples.

[0024] Example

[0025] See also Figure 1 The electrodialysis partition water distribution test device of this embodiment includes a water tank 1, a water tank 2, a test frame 3, a test clamping plate 4, a test PVC board 5 and a water pump 6. The water tank 1 and the water tank 2 are both placed on the test frame 3. The test clamping plate 4 and the test PVC board 5 are connected and fixed on the test frame 3. The partition to be tested is placed between the test clamping plate 4 and the test PVC board (5). The water pump 6 is installed on the test frame 3.

[0026] In this embodiment, a water inlet float flowmeter is arranged between the water pump 6 and the test clamping plate 4 .

[0027] The test clamping plate 4 and the test PVC plate 5 in this embodiment have the same area; the test clamping plate 4 and the test PVC plate 5 are both made of transparent acrylic plates.

[0028] When in use, two 40 L water tanks 1 and 2 are filled with pure water 1 and red ink 2 (potassium permanganate configuration), respectively, and placed on the test frame 3. The partition to be tested is placed in the middle of two custom-made partition splints (test clamping plate 4 and test PVC plate 5) of the same area, that is, the test frame 3 and the test clamping plate 4, and the surroundings are sealed by tightening PE foam material with bolts. Open the bottom valve of the pure water tank 1, and use the water pump 6 to transport pure water to the inside of the partition splint. After the inside is filled with water, close the pure water bucket valve. Open the bottom valve of the red ink tank 2, and transport it to the lower water inlet of the partition splint through the water pump 6. A water inlet float flowmeter is set between the water pump 6 and the partition splint. After the test starts, observe the hydraulic distribution of the partition according to the diffusion of the color solution. When the red ink begins to spread, adjust the valve at the outlet of pump 6 to control the variable flow rate, record the time when the color appears from the bottom of the partition to the top of the partition, the time when the internal color solution fills the partition, the time when the color solution in different parts diffuses 1 inch in the grid, and measure the dead zone area. Finally, based on the comparison of the relationship between the color change and diffusion time of each part of the partition, the uniformity of the partition distribution is visually detected. The evaluation indicators include the speed of the unit size chromaticity diffusion time, the size of the dead zone area, the speed of the surface flow rate and the uniformity analysis to determine where the partition needs to be optimized. The optimization includes the optimization of the number of water distribution outlets and the shape of the water distribution sheets, the change of the interweaving angle of the water distribution grid, the optimization of the flow rate of the water distribution holes and the optimization of the thickness of the partition, etc., to solve the problems of the partition in a targeted manner.

[0029] Traditional analysis methods require a variety of complex analysis equipment, with high investment costs, large amounts of data to analyze, and are mostly limited to written theoretical analysis, which is not enough to guide the production of separators. This solution can provide analysts with a more direct, transparent, and easier-to-understand analysis method to more quickly and accurately find separator design defects, thereby optimizing and improving separator performance, and ultimately improving the uniformity of water distribution inside the electrodialysis membrane stack.

[0030] Through the above description, those skilled in the art can already implement it.

[0031] In addition, it should be noted that the shapes and names of the parts and components of the specific embodiments described in this specification may be different, and the above content described in this specification is only an example of the structure of the utility model. All equivalent changes or simple changes made based on the structure, features and principles described in the patent concept of the utility model are included in the protection scope of the utility model patent. Technicians in the technical field of the utility model can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the utility model or exceed the scope defined by the claims, they should all fall within the protection scope of the utility model.

Claims

1. An electrodialysis separator water distribution test device, comprising a water tank 1 (1), a water tank 2 (2) and a test frame (3), wherein the water tank 1 (1) and the water tank 2 (2) are both placed on the test frame (3), and characterized in that: It also includes a test clamping plate (4), a test PVC plate (5) and a water pump (6), wherein the test clamping plate (4) and the test PVC plate (5) are connected and fixed on the test frame (3), a partition to be tested is placed between the test clamping plate (4) and the test PVC plate (5), and the water pump (6) is installed on the test frame (3).

2. The electrodialysis separator water distribution test device according to claim 1, characterized in that: A water inlet float flowmeter is provided between the water pump (6) and the test clamping plate (4).

3. The electrodialysis separator water distribution test device according to claim 1, characterized in that: The test clamping plate (4) and the test PVC plate (5) have the same area size.

4. The electrodialysis separator water distribution test device according to claim 1, characterized in that: The test clamping plate (4) and the test PVC plate (5) are both made of transparent acrylic plates.

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