A low-loss sampling device and method for powder agglomeration in a fluidized bed

Abstract

The present invention relates to a low-loss sampling device and method for powder agglomerates in a fluidized bed, comprising a fluidized bed, a pulse generating module, a sampling module, and a sedimentation and dispersion module. One end of the sampling module is connected to the sampling port of the fluidized bed, and the other end of the sampling module is connected to the sedimentation and dispersion module. The pulse generating module is connected to the pulse air inlet interface of the fluidized bed, and the sample in the fluidized bed is blown to the sampling module via the pulse airflow and enters the sedimentation and dispersion module. The use of a non-contact pulse airflow blowing sampling method effectively reduces the damage caused by sampling to the powder agglomerate structure, significantly improves the authenticity and accuracy of the sampling results, and contributes to the process control optimization of the fluidized bed process and the scientific research of the fluidization behavior of cohesive powders.

Description

Technical field:

[0001] The invention relates to a low-loss sampling device and method for powder agglomeration in a fluidized bed. Background technology:

[0002] Fluidization technology utilizes airflow to propel solid particles into suspension, causing a previously fixed bed of particles to exhibit fluid-like flow characteristics. Due to its controllable and scalable particle processing capabilities, fluidization technology has been widely used in various chemical processes, including separation, granulation, drying, and catalytic cracking.

[0003] Cohesive powders, with average particle sizes ranging from 1 to 4000 nanometers, possess significant specific surface area and unique physicochemical properties (such as surface effects, small size effects, and quantum effects). They play a crucial role in industries such as polymer materials, biomedicine, chemical catalysis, and electronics. These powders are prone to agglomeration during fluidization, reaching a dynamic equilibrium between fragmentation and reagglomeration. Agglomerates are stably distributed within the fluidized bed, significantly impacting fluidization performance. Sampling these agglomerates is crucial for revealing the fluidization characteristics of cohesive powders.

[0004] Fluidized beds are generally equipped with sampling devices. Sampling is crucial for accurately evaluating and effectively controlling particle distribution, reaction conditions, and product quality within the fluidized bed. However, the current fluidized bed sampling method is contact sampling, which can be divided into manual and automatic tool sampling, such as a fluidized bed sampler (CN202223226743.X), a fluidized bed rapid sampling device (CN202021470989.X), and a fluidized bed closed sampling device (CN202121595382.9). However, these two sampling methods require direct contact with the sample, and the sampling process inevitably affects the sample morphology.

[0005] Non-contact sampling methods can avoid the disturbance caused by direct contact, but are currently mainly used for gas-liquid phase analysis technology, such as a purge sampling valve for high-purity gas analysis (CN201511013739.7), a purge sampling system and purge sampling method for gas impurity content analysis (CN201410270358.6), and a nitrogen purge sampling valve (CN202022077644.4). For solid-phase samples, relevant sampling technologies are scarce, with only one patent reporting a hot air purge sampling device (CN201110324993.4), which is suitable for sampling with an ion mobility spectrometer. However, because the ion mobility spectrometer does not require sample morphology, this device has limitations when dealing with powder agglomerates:

[0006] (1) The sample accumulates in the sampling tube, which may affect the sample morphology; (2) The sample accumulation cross-section is only 1 square centimeter, and the sample cannot be effectively dispersed, which is inconvenient for subsequent image processing; (3) During the final removal of the sample attachment sheet, friction occurs between the sample attachment sheet and the wall of the sample trough, which will cause secondary destruction of the sample morphology.

[0007] In summary, there is an urgent need to develop a fluidized bed non-contact sampling technology that can maintain the integrity of the sample morphology and achieve effective dispersion. Summary of the invention:

[0008] The present invention aims to improve the problems existing in the above-mentioned prior art. Specifically, the present invention aims to provide a low-loss sampling device and method for powder agglomeration in a fluidized bed.

[0009] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a low-loss sampling device for powder agglomeration in a fluidized bed, comprising a fluidized bed, a pulse generating module, a sampling module and a sedimentation and dispersion module, one end of the sampling module is connected to the sampling port of the fluidized bed, and the other end of the sampling module is connected to the sedimentation and dispersion module; the pulse generating module is connected to the pulse air inlet interface of the fluidized bed, and the sample in the fluidized bed is blown to the sampling module by the pulse airflow and enters the sedimentation and dispersion module.

[0010] Furthermore, the pulse generating module includes a gas storage tank, a rotor flowmeter, a mass flowmeter and an electromagnetic valve connected in sequence, and the air outlet of the electromagnetic valve is connected to the pulse air inlet interface of the fluidized bed.

[0011] Furthermore, the pulse generating module also includes a programmable logic controller and a desktop computer. The programmable logic controller is electrically connected to the electromagnetic valve and controls the periodic opening and closing of the electromagnetic valve; the desktop computer is electrically connected to the mass flow meter to monitor the flow data in real time communication.

[0012] Furthermore, the fluidized bed includes a fluidized bed body and an air distribution box arranged at the bottom of the fluidized bed body, and the air inlet end of the air distribution box is connected to the air outlet of the electromagnetic valve.

[0013] Furthermore, the pulse generating module generates a pulse frequency in the range of 0-6 Hz and a pulse average gas volume between 0.75-3 liters per minute.

[0014] Furthermore, the side wall of the fluidized bed is provided with a plurality of sampling ports evenly spaced vertically; the sampling module includes a plurality of sampling tubes corresponding to the positions of the plurality of sampling ports, the sampling tubes are inclined with the left end higher and the right end lower, the upper ends of the sampling tubes are threadedly connected to the sampling ports corresponding to the positions, and each sampling tube is provided with a control valve.

[0015] Furthermore, the sedimentation and dispersion module includes a sample sedimentation container arranged on the right side of the fluidized bed, and the left wall of the sample sedimentation container is provided with perforations corresponding to the positions of multiple sampling tubes. The sampling tubes pass through the perforations corresponding to the positions and extend into the interior of the sample sedimentation container. The inner bottom surface of the sample sedimentation container is covered with multiple glass slides.

[0016] Furthermore, the top cover of the sample sedimentation container is provided with a top cover, and the top cover is provided with an exhaust port.

[0017] Furthermore, the sampling tube has an inclination angle of 30-45 degrees.

[0018] Another technical solution adopted by the present invention is: a low-loss sampling method for powder agglomerates in a fluidized bed. When sampling: first, open the gas storage tank, start the programmable logic controller and adjust the rotor flowmeter to generate a pulsed airflow with appropriate gas volume and pulse frequency; then open the control valve on the sampling tube at the sampling position where sampling is required, and the sample in the fluidized bed is gently blown out of the sampling tube by the pulsed airflow. The sample falls along the sampling tube into the sample sedimentation container and freely settles in the sample sedimentation container, and is finally dispersed on the glass slide at the bottom of the sample sedimentation container; after a certain sampling time, close the control valves on the gas storage tank and the sampling tube, remove the top cover of the sedimentation container, and take out the glass slide to obtain the required sample.

[0019] Compared with the existing technology, the present invention has the following effects: the present invention is reasonably designed, adopts pulse airflow sampling, and realizes multi-point low-loss sampling in the fluidized bed through gentle pulse purge and multi-point sampling ports, effectively improving the authenticity and accuracy of the results, while the sampling operation is simple. Description of the drawings:

[0020] Figure 1 Schematic diagram of the structure of an embodiment of the present invention;

[0021] Figure 2 is the comparison of in situ aggregate size with manual and pulse sampling aggregate size;

[0022] Figure 3 is a comparison of the in situ aggregate size distribution with that of manual and pulse sampling.

[0023] In the picture:

[0024] 1-gas storage tank; 2-rotameter; 3-mass flowmeter; 4-desktop computer; 5-electromagnetic valve; 6-programmable logic controller; 7-fluidized bed; 701-fluidized bed body; 702-air distribution box; 8-sampling tube; 9-sample sedimentation container; 10-glass slide; 11-exhaust port; 12-top cover. Specific implementation:

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0027] Pulsed airflow—that is, air flow that periodically increases and decreases in intensity—has demonstrated unique advantages in promoting and controlling the movement of solid particles in pulsed pneumatic conveying systems, for example, in clearing deposits from pipe walls or achieving efficient material transfer. By manipulating the frequency and amplitude of the pulsed airflow, it is possible to gently entrain powder agglomerates while maintaining their original form.

[0028] like Figure 1 As shown, the present invention is a low-loss sampling device for powder agglomerates in a fluidized bed. It realizes low-loss sampling from a fluidized bed of powder agglomerates based on pulse flow. Specifically, it includes a fluidized bed 7, a pulse generating module, a sampling module, and a sedimentation dispersion module. One end of the sampling module is connected to the sampling port of the fluidized bed 7, and the other end of the sampling module is connected to the sedimentation dispersion module. The pulse generating module is connected to the pulse air inlet interface of the fluidized bed. The sample in the fluidized bed is swept to the sampling module by the pulse airflow and enters the sedimentation dispersion module. It is freely settled in the sedimentation dispersion module to achieve effective dispersion of the sample. The use of a non-contact pulse airflow purging sampling method effectively reduces the damage caused by sampling to the powder agglomerate structure, significantly improves the authenticity and accuracy of the sampling results, and contributes to the process control optimization of the fluidized bed process and the scientific study of the fluidization behavior of cohesive powders.

[0029] In this embodiment, the fluidized bed 7 includes a fluidized bed body 701 and an air distribution box 702 arranged at the bottom of the fluidized bed body 701. The air inlet end of the air distribution box is the pulse air inlet interface of the entire fluidized bed.

[0030] In this embodiment, the pulse generation module includes a gas storage tank 1, a rotameter 2, a mass flowmeter 3, and a solenoid valve 5, all connected in sequence. The outlet of the solenoid valve 5 is connected to the air inlet of the air distribution box 702 of the fluidized bed 7, facilitating the delivery of pulsed airflow into the fluidized bed. The gas storage tank serves as the air source for the pulse generation module, and the rotameter regulates the inlet air flow.

[0031] In this embodiment, the pulse generating module further includes a programmable logic controller 6 and a desktop computer 4. The programmable logic controller 6 is electrically connected to the electromagnetic valve 5. The programmable logic controller 6 controls the periodic opening and closing of the electromagnetic valve 5 by setting parameters through software, thereby generating a pulsed airflow. The desktop computer 4 is electrically connected to the mass flow meter 3 to monitor the flow data in real time communication.

[0032] In this embodiment, the air inlet and outlet of the electromagnetic valve are equipped with ferrule interfaces and matching air pipes, and the air inlet end of the air distribution box is equipped with a quick connector socket to facilitate quick connection with the air outlet of the electromagnetic valve.

[0033] In this embodiment, the pulse generation module generates a pulse frequency in the range of 0-6 Hz and an average pulse gas volume of 0.75-3 liters per minute. This pulse frequency range minimizes damage to the agglomerate structure, while also providing sufficient gas volume to carry the agglomerated sample out of the bed. Furthermore, the pulse generation module can select the optimal pulse conditions within this parameter range for each powder sample, thereby preserving the sample's original morphology and size.

[0034] In this embodiment, the side wall of the fluidized bed body 701 is provided with a plurality of sampling ports evenly spaced vertically. The sampling ports are threaded holes with a depth of 10-30 mm and a diameter of 8-15 mm.

[0035] In this embodiment, the sampling module includes multiple sampling tubes 8 corresponding to the positions of the multiple sampling ports. The sampling tubes 8 are inclined with the left end higher and the right end lower. The upper ends of the sampling tubes 8 are threadedly connected to the corresponding sampling ports, and the lower ends of the sampling tubes are beveled. Each sampling tube 8 is provided with a control valve for controlling the on / off of the sampling tube. Preferably, the control valve can be a manual valve. Preferably, the sampling tubes are set to a length of 60-100 mm and an outer diameter of 10-12 mm.

[0036] In this embodiment, the sedimentation and dispersion module includes a sample sedimentation container 9 disposed on the right side of the fluidized bed 7. The left wall of the sample sedimentation container 9 is provided with perforations corresponding to the positions of multiple sampling tubes 8. The sampling tubes 8 extend into the interior of the sample sedimentation container 9 after passing through the corresponding perforations. The inner bottom surface of the sample sedimentation container 9 is paved with multiple slides 10. After free sedimentation, the sample is naturally dispersed on the slides 10. The slides 10 are 75-80 mm in length and 30-40 mm in width. Preferably, the diameter of the perforations is 8-10 mm larger than the outer diameter of the sampling tubes.

[0037] In this embodiment, the top cover of the sample sedimentation container 9 is provided with a top cover 12, which is detachably connected to the sample sedimentation container. The detachable top cover is convenient for collecting the slide 10 from the top opening of the sample sedimentation container; the top cover 12 is provided with an exhaust port 11 to facilitate the discharge of the pulsed airflow.

[0038] In this embodiment, the sampling tube 8 has an inclination angle of 30-45 degrees.

[0039] In this embodiment, a low-loss sampling method for powder agglomeration in a fluidized bed is provided. During sampling, the following steps are performed: first, the gas storage tank 1 is opened, the programmable logic controller 6 is started, and the rotor flowmeter 2 is adjusted to generate a pulsed airflow of appropriate gas volume and pulse frequency; then, the control valve on the sampling tube 8 at the desired sampling location is opened, and the sample in the fluidized bed 7 is gently purged out of the sampling tube 8 by the pulsed airflow. The sample falls along the sampling tube 8 into the sample sedimentation container 9 and freely settles within the sample sedimentation container 9, ultimately being dispersed onto the glass slide 10 at the bottom of the sample sedimentation container 9; after a certain sampling time, the control valves on the gas storage tank 1 and the sampling tube 8 are closed, the top cover 12 of the sedimentation container is removed, and the glass slide 10 is removed to obtain the desired sample. This sampling technology has the following characteristics: it ensures the accuracy of sample characteristics during the sampling process, supports multi-point sampling, can automatically complete sample dispersion, and has a simple device structure and a simple operating procedure. The use of this low-loss sampling technology can reveal the aggregation behavior and fluidization characteristics of cohesive powders during the fluidization process more deeply and accurately, which is helpful for the process control optimization of fluidized bed processes and the scientific study of cohesive fluidization behavior.

[0040] Example:

[0041] The low-loss sampling process of nano-SiO2 powder (primary particle size is 20nm) in fluidized bed will be combined with Figure 1 Specifically, 15-55g of dry nano-SiO2 powder is filled into the fluidized bed, and a stable airflow is introduced to fully fluidize it for a sufficient period of time;

[0042] (1) In the sampling preparation phase, first open the gas storage tank 1 and connect the pulse air inlet interface of the fluidized bed 7 to the pulse generating module, that is, to the electromagnetic valve 5;

[0043] (2) Ensure that the communication line between the electromagnetic valve 5 and the programmable logic controller 6 is unobstructed, and verify that the compiled file parameters in the desktop computer 4 are accurate;

[0044] (3) Importing the file into the programmable logic controller 6 and starting it, so that the electromagnetic valve opens and closes periodically to generate pulsed airflow;

[0045] (4) Adjust the rotor flowmeter 2 and coordinate with the mass flowmeter 3 to monitor the airflow conditions until the required pulse gas volume value is reached;

[0046] (5) Open the corresponding sampling tube at the preset sampling port position, thereby connecting the interior of the fluidized bed body with the external sample sedimentation container 9;

[0047] (6) With the regular impact of the pulsed airflow, the sample is gently blown out of the fluidized bed and freely settles in the sample sedimentation container 9, and is finally dispersed on the glass slide 10 at the bottom of the container;

[0048] (7) After a certain sampling time, close the gas storage tank 1 and observe that the mass flow meter 3 returns to zero, indicating that the airflow has completely stopped. Stop the programmable logic controller, and then close the bed sampling tube 8 control valve to seal the sampling port. This completes the basic sampling process at one location. If you need to repeat the sampling at other different locations, just repeat the above steps in this cycle. By using a non-contact controllable pulse airflow to purge the sample, the damage caused by sampling to the powder agglomerate structure is effectively reduced, and the authenticity and accuracy of the sampling results are significantly improved (see Figure 3 ), which is helpful for the process control optimization of fluidized bed technology and the scientific study of the fluidization behavior of cohesive powders.

[0049] Furthermore, for cohesive powders that form soft agglomerates, such as SiO2, BaF, and Al2O3 powders, the pulse conditions are selected as follows: a pulse frequency range of 0.5-1.67 Hz and an average pulse gas volume range of 0.75-1 liter per minute. This pulse frequency range minimizes damage to the soft agglomerate structure, while also providing sufficient gas volume to carry the agglomerated sample out of the bed.

[0050] Furthermore, for cohesive powders that form hard agglomerates, such as TiO2, B4C, and lactose powders, the pulse conditions are selected as follows: a pulse frequency range of 0.5-3 Hz and an average pulse gas volume range of 1-2.5 liters per minute. This pulse frequency range minimizes damage to the hard agglomerate structure, while also providing sufficient gas volume to carry the agglomerated sample out of the bed.

[0051] In view of the limitations of existing solid phase sampling technology, this paper proposes a non-contact sampling method based on programmable controlled pulse air purge, which effectively ensures the integrity of the agglomerate morphology. The effect of this pulse sampling method on the agglomerate size can be controlled within 8-15% (see Table 1). This technology integrates purge sampling and sample dispersion, allowing the sample to enter the sedimentation container through the sampling tube and settle naturally to achieve effective dispersion (see Figure 2 ), which is beneficial for subsequent image processing and analysis (see Figure 3 ). In addition, the sample is collected by taking out the slide from the opening above the sample sedimentation container, which effectively prevents secondary damage to the sample morphology during the collection process.

[0052] Table 1

[0053]

[0054] The advantages of the present invention are that: with the help of controllable pulse airflow, the agglomerated samples at the required sampling points in the fluidized bed are controllably blown out from the sampling port, and the samples are effectively dispersed during the free sedimentation process. During the entire sampling process, the original shape and size of the samples are maintained to the maximum extent, thereby significantly improving the authenticity and accuracy of the sampling results; at the same time, the sampling operation is simple, and the advantage of low-loss sampling can be achieved for samples at different point heights in the fluidized bed.

[0055] If the present invention discloses or involves components or structures that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, connection using bolts or screws), and can also be understood as: a non-detachable fixed connection (for example, riveting, welding). Of course, the mutual fixed connection can also be replaced by an integrated structure (for example, manufactured by integral molding using a casting process) (except where it is obviously not possible to use an integrated molding process).

[0056] In addition, unless otherwise stated, the terms used in any technical solution disclosed in the present invention to express positional relationships or shapes include states or shapes that are approximate, similar, or close thereto.

[0057] Any component provided by the present invention may be assembled from multiple separate components, or may be a separate component manufactured by an integral molding process.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solutions of the present invention. They should all be included in the scope of the technical solutions claimed for protection by the present invention.

Claims

1. A low-loss sampling device for powder agglomeration in a fluidized bed, comprising a fluidized bed, characterized in that: The system also includes a pulse generating module, a sampling module, and a settling and dispersing module. One end of the sampling module is connected to the sampling port of the fluidized bed, and the other end of the sampling module is connected to the settling and dispersing module. The pulse generating module is connected to the pulse air inlet interface of the fluidized bed. The sample in the fluidized bed is swept to the sampling module by the pulse airflow and enters the settling and dispersing module. The pulse generating module comprises a gas storage tank, a rotor flowmeter, a mass flowmeter and an electromagnetic valve connected in sequence, wherein the gas outlet of the electromagnetic valve is connected to the pulse gas inlet interface of the fluidized bed; The pulse generation module further includes a programmable logic controller and a desktop computer. The programmable logic controller is electrically connected to the electromagnetic valve and controls the periodic opening and closing of the electromagnetic valve. The desktop computer is electrically connected to the mass flow meter to monitor flow data in real time. The side wall of the fluidized bed is provided with a plurality of sampling ports evenly spaced vertically; the sampling module includes a plurality of sampling tubes corresponding to the positions of the plurality of sampling ports, the sampling tubes being inclined with the left end higher and the right end lower, the upper ends of the sampling tubes being threadedly connected to the corresponding sampling ports, and each sampling tube being provided with a control valve; The sedimentation and dispersion module includes a sample sedimentation container arranged on the right side of the fluidized bed, the left wall of the sample sedimentation container is provided with perforations corresponding to the positions of multiple sampling tubes, the sampling tubes pass through the corresponding perforations and extend into the interior of the sample sedimentation container, and the inner bottom surface of the sample sedimentation container is paved with multiple slides; The top cover of the sample sedimentation container is provided with a top cover, and the top cover is provided with an exhaust port.

2. The low-loss sampling device for powder agglomeration in a fluidized bed according to claim 1, characterized in that: The fluidized bed comprises a fluidized bed body and an air distribution box arranged at the bottom of the fluidized bed body, and the air inlet end of the air distribution box is connected to the air outlet of the electromagnetic valve.

3. The low-loss sampling device for powder agglomeration in a fluidized bed according to claim 1, characterized in that: The pulse generation module generates a pulse frequency in the range of 0-6 Hz and a pulse average gas volume between 0.75-3 liters per minute.

4. The low-loss sampling device for powder agglomeration in a fluidized bed according to claim 1, characterized in that: The inclination angle of the sampling tube is 30-45 degrees.

5. A low-loss sampling method for powder agglomerates in a fluidized bed, characterized by: The invention comprises a low-loss sampling device for powder agglomeration in a fluidized bed as described in any one of claims 1 to 4. When sampling, first, the gas storage tank is opened, the programmable logic controller is started and the rotor flowmeter is adjusted to generate a pulsed airflow with a suitable gas volume and pulse frequency; then the control valve on the sampling tube at the sampling position to be sampled is opened, and the sample in the fluidized bed is gently blown out of the sampling tube by the pulsed airflow, and the sample falls into the sample sedimentation container along the sampling tube and freely settles in the sample sedimentation container, and is finally dispersed on the glass slide at the bottom of the sample sedimentation container; after a certain sampling time, the control valves on the gas storage tank and the sampling tube are closed, the top cover of the sedimentation container is removed, and the glass slide is taken out to obtain the required sample.

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