Modeling and measurement system of gas-solid drag and mass transfer in fluidized bed based on 3D printing technology

Abstract

The present invention discloses a gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology, which relates to the field of fluidization and fluidized bed technology. In order to develop an accurate drag and mass transfer measurement method in a fluidized bed gas-solid system, a stable particle fluidization structure is designed and printed using high-precision 3D printing technology. Gas channels one and two are connected to the bottom of a fluidization structure fixture to supply airflow, and the tube wall of the fluidization structure fixture is provided with pressure measuring ports at different positions. The present invention can design and prepare different types of stable particle fluidization structures through 3D printing technology, thereby accurately measuring the drag of different types of fluidization structures. Gas channels one and two can adjust the gas volume in different measuring ranges, thereby improving the accuracy of the measurement results. And on this basis, by tracking the concentration changes of the tracer gas, the gas-solid mass transfer mechanism of the particle agglomerate fluidization structure is revealed.

Description

Technical Field

[0001] The present invention relates to the field of fluidization and fluidized bed technology, and in particular to a gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology. Background Art

[0002] Gas-solid fluidized beds feature continuous particle flow, uniform bed temperature, and excellent heat transfer, making them widely used in key processes in the chemical and energy industries, such as heavy oil catalytic cracking, coal and biomass gasification, flue gas purification, polysilicon production, and carbon nanotube production. Against the backdrop of achieving peak carbon emissions and achieving carbon neutrality, my country's industry is undergoing a transition period of industrial upgrading and energy conservation and emission reduction. There is an urgent need to develop efficient fluidized beds to replace certain high-energy-consuming reactors such as rotary kilns and moving beds, and to further optimize existing industrial fluidized beds.

[0003] For a gas-solid fluidized bed, drag is the core of the gas-solid interaction mechanism and directly determines the accuracy of computational fluid simulation results. Therefore, obtaining a gas-solid drag model for a fluidized bed is of great significance.

[0004] In the existing literature, the commonly used fluidized bed gas-solid drag models include the Wen-Yu drag model, the Ergun drag model, the Gidaspow drag model, the Schiller-Naumann drag model, the Arastoopour drag model, the Syamlal-O'Brien drag model, the DiFelice drag model, and the Gibilaro drag model.

[0005] Existing technologies face the following challenges: Limited by traditional experimental methods, researchers are unable to achieve a stable fluidized structure of gas-solid particles, making it impossible to accurately quantify the intrinsic gas-solid interaction mechanism within the fluidized bed. This results in a 3-4-fold discrepancy between the drag models commonly used. Regarding mass transfer models, literature indicates that the gas-solid mass transfer coefficient within a gas-solid fluidized bed varies by three orders of magnitude, making it difficult to predict fluidized bed reactions using commonly used empirical mass transfer formulas (e.g., Kall (1953), Bolland (1998), and Venderborsch (1999)).

[0006] To this end, the present invention proposes a gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology. Summary of the Invention

[0007] The purpose of the present invention is to solve the shortcomings of the existing technology and propose a gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] The gas-solid drag force mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology includes gas channel 1, gas channel 2 and a fluidization structure fixing device ( Figure 1 ),

[0010] The fluidized structure fixture is provided with a particle fluidized structure in the middle portion. This particle fluidized structure is formed by 3D printing, with particle diameters ranging from 20-2000 μm, a solid content range of 0-0.65, a particle agglomerate diameter range of 1-50 mm, and a particle sphericity range of 0.5-1. A gas distribution plate is fixed to the bottom of the fluidized structure fixture, and gas channels one and two are connected to the bottom of the fluidized structure fixture to supply air. Pressure measuring ports are opened at different locations on the fluidized structure fixture's wall, and these pressure measuring ports are connected to the same differential pressure sensor via a connecting pipe.

[0011] Preferably: when the solid content of the particle fluidized structure is less than 0.25, the cross section of the particle fluidized structure (5) is a combination of several rectangles, the width of the rectangle is 2-3 times the diameter of the constituent particles, and each rectangular unit is separated by a grid structure. Further: when the solid content of the particle fluidized structure is greater than 0.25, the cross section of the particle fluidized structure is circular, which is equal to the fluidized structure fixing device ( Figure 1 ) inner diameter.

[0012] On the basis of the above scheme: flange one, flange two, flange three and flange four are welded in the fluidization structure fixing device, and the particle fluidization structure is fixed to the middle part of the fluidization structure fixing device through the above two pairs of flanges.

[0013] A better solution among the above solutions is that: a sealing ring 1 is provided on the side opposite to the flange 1 and the flange 2, and a sealing ring 2 is provided on the side opposite to the flange 3 and the flange 4.

[0014] As a further solution of the present invention: the air flow supply mechanism includes an air compressor / gas cylinder, a pressure reducing valve and a filter connected in sequence, and the other end of the filter is connected to the bottom of the fluidized bed through a flow monitoring component.

[0015] At the same time, the flow monitoring component includes a solenoid valve A, a mass flowmeter A, a one-way valve A connected in sequence, and a solenoid valve B, a mass flowmeter B, and a one-way valve B connected in sequence. The solenoid valve A and the solenoid valve B are connected in parallel to the filter, and the one-way valve A and the one-way valve B are connected in parallel to the bottom of the fluidization structure fixing device.

[0016] As a preferred embodiment of the present invention, the mass flowmeter A is a low-flow mass flowmeter, and the mass flowmeter B is a high-flow mass flowmeter.

[0017] Meanwhile, its use method includes the following steps:

[0018] S1: First, a particle fluidization structure is produced using 3D printing technology according to the type of fluidized bed to be measured;

[0019] S2: Then, without installing the particle fluidization structure, start the air compressor / gas cylinder to introduce air flow to the bottom of the fluidization structure fixture, and determine the pressure loss through the reading of the differential pressure sensor;

[0020] S21: When the airflow is large, open the solenoid valve B and close the solenoid valve A;

[0021] S22: When the airflow is small, open the solenoid valve A and close the solenoid valve B;

[0022] S3: After the particle fluidization structure is installed, the solenoid valve is started again. The gas-solid drag force of the particle fluidization structure can be calculated by subtracting the pressure loss from the reading of the differential pressure sensor.

[0023] The beneficial effects of the present invention are:

[0024] 1. The present invention can design and prepare different types of particle fluidization structures by utilizing 3D printing technology, thereby establishing an accurate gas-solid fluidized bed system drag model and particle agglomeration mass transfer model. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic cross-sectional view of the fluidization structure fixing device of the gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology proposed by the present invention;

[0026] Figure 2 This is a schematic diagram of the airflow supply mechanism pipeline of the gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology proposed in the present invention.

[0027] Figure 3 Schematic diagram of the fluidized bed agglomerate structure mass transfer experiment based on 3D printing technology proposed in this invention.

[0028] In the figure: 2a-flange 1, 3a-sealing ring 1, 4a-flange 2, 2b-flange 3, 3b-sealing ring 2, 4b-flange 4, 5-particle fluidization structure, 6-flange 4, 7-gas distribution plate, 8, 9-vent, 10-connecting pipe, 11-differential pressure sensor, 12-air compressor, 13-pressure reducing valve, 14-filter, 15-solenoid valve A, 16-mass flowmeter A, 17-check valve A, 18-check valve B, 19-mass flowmeter B, 20-solenoid valve B. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be further described in detail below in conjunction with specific implementation methods.

[0030] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0031] Example 1:

[0032] Gas-solid drag and mass transfer modeling and measurement system in fluidized bed based on 3D printing technology, such as Figure 1-2 As shown, it includes gas channel one, gas channel two and a fluidized structure fixing device. A uniform suspended particle structure is provided in the middle part of the fluidized structure fixing device. The uniform suspended particle structure is formed by 3D printing. A gas distribution plate is fixed in the bottom of the fluidized structure fixing device, and gas channels one and two are connected to the bottom of the fluidized structure fixing device to supply airflow. Pressure measuring ports are opened at different positions on the tube wall of the fluidized structure fixing device, and the pressure measuring ports are connected to the same differential pressure sensor through a connecting pipe.

[0033] When the solid content of the uniform suspended particle structure 5 is less than 0.25, the cross section of the uniform suspended particle structure is a rectangle, and the width of the rectangle is 2-3 times the diameter of the constituent particles.

[0034] When the solid content of the uniform suspended particle structure 5 is greater than 0.25, the cross section of the uniform suspended particle structure is circular, which is equal to the fluidized structure fixing device ( Figure 1 ) inner diameter.

[0035] The pipe walls of the fluidized structure fixing device are welded with flange 1, flange 2, flange 3 and flange 4, and the uniformly suspended particle structure is fixed to the middle part of the fluidized bed through the above two pairs of flanges.

[0036] A sealing ring 1 3a is provided on the side of the flange 1 2a opposite to the flange 2 4a, and a sealing ring 2 3b is provided on the side of the flange 3 2b opposite to the flange 4 4b.

[0037] When using this embodiment, first directly connect gas channel 1 and gas channel 2 to the fluidized structure fixing device, then supply gas to the bottom of the fluidized structure fixing device through the airflow supply mechanism, read the pressure loss through the pressure difference sensor 11, and then install the uniformly suspended particle structure 5. Then, supply gas to the bottom of the fluidized bed through the airflow supply mechanism again, read the reading of the pressure difference sensor 11, and after subtracting the pressure loss, the gas-solid drag force of the uniformly suspended particle structure 5 can be calculated. Example 2:

[0038] Gas-solid drag and mass transfer modeling and measurement system in fluidized bed based on 3D printing technology, such as Figure 2 As shown, this embodiment makes the following improvements based on the embodiment 1: the particle fluidization structure 5 is changed from the uniform suspension structure of the embodiment 1 to a particle agglomeration structure.

[0039] When the solid content of the particle agglomerate structure 5 is less than 0.25, the cross-section of the particle agglomerate structure is a rectangle, and the width of the rectangle is 2-3 times the diameter of the constituent particles.

[0040] When the solid content of the particle agglomerate structure 5 is greater than 0.25, the cross section of the particle agglomerate structure is circular, and the agglomerate diameter ranges from 1 to 50 mm.

[0041] The pipe walls of the fluidized structure fixing device are welded with flange 1, flange 2, flange 3 and flange 4, and the particle agglomeration structure is fixed to the middle part of the fluidized bed through the above two pairs of flanges.

[0042] A sealing ring 1 3a is provided on the side of the flange 1 2a opposite to the flange 2 4a, and a sealing ring 2 3b is provided on the side of the flange 1 2b opposite to the flange 2 4b.

[0043] When this embodiment is in use, first directly connect gas channel 1 and gas channel 2 to the fluidized structure fixing device, then supply gas to the bottom of the fluidized structure fixing device through the airflow supply mechanism, read the pressure loss through the pressure difference sensor 11, and then install the particle agglomeration structure 5. Then, supply gas to the bottom of the fluidized bed through the airflow supply mechanism again, read the reading of the pressure difference sensor 11, and after subtracting the pressure loss, the gas-solid drag of the particle agglomeration structure 5 can be calculated. Example 3:

[0044] Gas-solid drag and mass transfer modeling and measurement system in fluidized bed based on 3D printing technology, such as Figure 3 As shown, this embodiment makes the following improvements on the basis of embodiment 2: a carbon dioxide concentration probe is installed in the particle agglomeration fluidization structure 5, and after the reading of the differential pressure sensor 11 stabilizes, the air flow is switched to an air flow containing 10% carbon dioxide, and the carbon dioxide probe is used to monitor the change of carbon dioxide concentration in the agglomerate in real time, and the mass transfer rate between the agglomerate and the air is calculated.

[0045] When the solid content of the particle agglomerate structure 5 is less than 0.25, the cross-section of the particle agglomerate structure is a rectangle, and the width of the rectangle is 2-3 times the diameter of the constituent particles.

[0046] When the solid content of the particle agglomerate structure 5 is greater than 0.25, the cross-section of the particle agglomerate structure is circular with a diameter ranging from 1 to 50 mm.

[0047] The pipe walls of the fluidized structure fixing device are welded with flange 1, flange 2, flange 3 and flange 4, and the particle agglomeration structure is fixed to the middle part of the fluidized bed through the above two pairs of flanges.

[0048] A sealing ring 1 3a is provided on the side of the flange 1 2a opposite to the flange 2 4a, and a sealing ring 2 3b is provided on the side of the flange 1 2b opposite to the flange 2 4b.

[0049] When using this embodiment, first directly connect gas channel 1 and gas channel 2 to the fluidized structure fixing device, install the particle agglomeration structure 5, and then supply gas to the bottom of the fluidized structure fixing device through the airflow supply mechanism. After the reading of the pressure difference sensor 11 stabilizes, the airflow is switched to an airflow containing 10% carbon dioxide. The carbon dioxide probe is used to monitor the change of carbon dioxide concentration in the agglomerate in real time, and the mass transfer rate between the agglomerate and the airflow is calculated.

[0050] The gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology includes the following steps:

[0051] S1: First, according to the type of fluidized bed to be measured, a particle fluidization structure 5 is made using 3D printing technology. Experimental variables such as particle size and sphericity can be achieved through 3D design and adjustment of the printing parameters of the 3D printer. According to different requirements for solid content (ratio of particle volume to total volume), a Python program is written to output the coordinates of randomly removed particles without affecting the 3D printing results. S2: Then, without installing the particle fluidization structure 5, the air compressor 12 is started to move the fluidized bed ( Figure 1 ) is introduced into the bottom of the device, and the pressure loss is determined by the reading of the differential pressure sensor 11;

[0052] S21: When the airflow is large, the solenoid valve B20 is opened and the solenoid valve A15 is closed;

[0053] S22: When the airflow is small, open the solenoid valve A15 and close the solenoid valve B20;

[0054] S3: After the particle fluidization structure 5 is installed, the solenoid valve is started and the gas-solid drag force of the particle fluidization structure 5 is calculated by subtracting the pressure loss from the reading of the differential pressure sensor 11 .

[0055] Mass transfer measurement experimental steps

[0056] S1: First, according to the type of fluidized bed to be measured, a particle agglomeration fluidization structure 5 is manufactured using 3D printing technology, and a carbon dioxide concentration probe is installed inside the particle agglomeration fluidization structure 5;

[0057] S2: Start the air compressor / gas cylinder 12-way fluidization structure fixing device ( Figure 1 ) is fed into the bottom of the

[0058] S21: When the airflow is large, the solenoid valve B20 is opened and the solenoid valve A15 is closed;

[0059] S22: When the airflow is small, open the solenoid valve A15 and close the solenoid valve B20;

[0060] S3: After the reading of the differential pressure sensor 11 stabilizes, the air flow is switched to an air flow containing 10% carbon dioxide. The carbon dioxide concentration change in the agglomerate is monitored in real time using a carbon dioxide probe, and the mass transfer rate between the agglomerate and the air is calculated.

[0061] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A 3D printing-based fluidized bed gas-solid drag and mass transfer modeling and measurement system, comprising a gas channel 1, a gas channel 2, and a fluidization structure fixing device, characterized in that: A particle fluidization structure (5) is provided in a fixed middle portion of the fluidization structure fixing device, the particle fluidization structure (5) is formed by 3D printing, a gas distribution plate (7) is fixed in the bottom of the fluidization structure fixing device, and gas channels one and two are connected to the bottom of the fluidization structure fixing device to supply airflow, pressure measuring ports (8, 9) are opened at different positions on the tube wall of the fluidization structure fixing device, and the pressure measuring ports (8, 9) are connected to the same differential pressure sensor (11) through a connecting pipe (10); When the solid content of the particle fluidization structure (5) is less than 0.25, the cross section of the particle fluidization structure (5) is a combination of a plurality of rectangular units, the width of the rectangle being 2-3 times the diameter of the constituent particles, and each rectangular unit being separated by a grid structure; When the solid content of the particle fluidization structure (5) is greater than 0.25, the cross-section of the particle fluidization structure (5) is circular, which is equal to the inner diameter of the fluidization structure fixing device.

2. The gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology according to claim 1 is characterized in that: Flange 1 (2a), flange 2 (4a), flange 3 (2b), and flange 4 (4b) are welded in the fluidization structure fixing device, and the particle fluidization structure (5) is fixed to the middle part of the device through the above two pairs of flanges.

3. The gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology according to claim 2 is characterized in that: A sealing ring 1 (3a) is provided on the side opposite to the flange 1 (2a) and the flange 2 (4a), and a sealing ring 2 (3b) is provided on the side opposite to the flange 3 (2b) and the flange 4 (4b).

4. The gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology according to claim 3 is characterized in that: The air flow supply mechanism comprises an air compressor / gas cylinder (12), a pressure reducing valve (13) and a filter (14) which are connected in sequence, and the other end of the filter (14) is connected to gas channels one and two respectively.

5. The gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology according to claim 4 is characterized in that: The flow monitoring component comprises a solenoid valve A (15), a mass flow meter A (16), a one-way valve A (17) connected in sequence, and a solenoid valve B (20), a mass flow meter B (19), and a one-way valve B (18) connected in sequence, wherein the solenoid valve A (15) and the solenoid valve B (20) are connected in parallel to the filter (14), and the one-way valve A (17) and the one-way valve B (18) are connected in parallel to the bottom of the fluidized bed fluidization structure fixing device.

6. The gas-solid drag force and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology according to claim 5, characterized in that: The mass flowmeter A (16) is a low-flow mass flowmeter, and the mass flowmeter B (19) is a high-flow mass flowmeter.

7. The gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology according to claim 5, characterized in that: The method of use includes the following steps: S1: First, a particle fluidization structure (5) is produced using 3D printing technology according to the type of fluidized bed to be measured; S2: Then, without installing the particle fluidization structure (5), start the air compressor / gas cylinder (12) to introduce air flow to the bottom of the fluidization structure fixture, and determine the pressure loss through the reading of the pressure differential sensor (11); S21: When the airflow is large, the solenoid valve B (20) is opened and the solenoid valve A (15) is closed; S22: When the airflow is small, open the solenoid valve A (15) and close the solenoid valve B (20); S3: After the particle fluidization structure (5) is installed, the solenoid valve is started and the gas-solid drag force of the particle fluidization structure (5) can be calculated by subtracting the pressure loss from the reading of the differential pressure sensor (11).

8. The gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology according to claim 1, characterized in that: The particle fluidization structure (5) is programmed with a python program to output the coordinates of randomly removed particles according to different solid content requirements without affecting the 3D printing results.

9. The gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology according to claim 1, characterized in that: The gas types include compressed air, nitrogen, argon, and carbon dioxide.

10. The gas-solid drag and mass transfer modeling and measurement system in a fluidized bed based on 3D printing technology according to claim 5, characterized in that: The method of use includes the following steps: S1: First, according to the type of fluidized bed to be measured, a particle agglomeration fluidized structure (5) is manufactured using 3D printing technology, and a carbon dioxide concentration sensor or other tracer gas sensor is installed in the particle agglomeration fluidized structure (5); S2: Start the air compressor / gas cylinder (12) to introduce air flow to the bottom of the fluidized structure fixture; S21: When the airflow is large, the solenoid valve B (20) is opened and the solenoid valve A (15) is closed; S22: When the airflow is small, open the solenoid valve A (15) and close the solenoid valve B (20); S3: After the reading of the differential pressure sensor (11) is stabilized, the air flow is switched to an air flow containing 10% carbon dioxide. The carbon dioxide probe is used to monitor the concentration change of carbon dioxide or other tracer gases in the agglomerates in real time, and the mass transfer rate between the agglomerates and the air flow is calculated.

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