PHA emulsification preparation device based on high-shear ultrasonic technology

Abstract

The utility model discloses a PHA (polyhydroxyalkanoate) emulsification preparation device based on a high-shear ultrasonic technology, and belongs to the technical field of emulsion preparation. The device comprises a multi-path feeding system, a high-shear ultrasonic mixing cavity, a temperature control unit, a discharge and online detection system and an environment-friendly energy-saving module. And a high-speed rotating impeller and an ultrasonic transducer are coaxially arranged in the high-shear ultrasonic mixing cavity. Through the synergistic effect of high shear and ultrasound and in combination with online detection and feedback control, the particle size of the PHA emulsion can be efficiently refined to 100-200nm, and meanwhile, through the design of waste heat and solvent recovery, the production energy consumption and environmental pollution are reduced. The device solves the problems of large particle size, poor stability and high energy consumption of PHA emulsion in the prior art, and is suitable for the fields of bio-based packaging materials, barrier coatings and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of emulsion preparation, and particularly relates to a PHA emulsification preparation device based on high-shear ultrasonic technology. Background Art

[0002] Polyhydroxyalkanoates (PHA) are bio-based biodegradable polymer materials with application potential in the fields of bio-based packaging, barrier coatings, and medical materials. As an important application form of PHA, its preparation technology directly affects the product performance.

[0003] At present, the preparation methods of PHA emulsions mainly include high-shear method and ultrasonic emulsification method. For traditional high-shear equipment, the impeller speed is usually 3000 - 5000 rpm, and emulsions are prepared by strong mechanical shear force. However, the emulsions prepared by this method have larger particle sizes, usually in the range of 500 - 2000 nm, and a wide particle size distribution. The emulsion stability is poor, and after storage for a period of time, such as 30 days, stratification or sedimentation is likely to occur.

[0004] Single ultrasonic emulsification technology uses the cavitation effect of ultrasonic waves to break droplets, and can refine the emulsion particle size to 200 - 500 nm. However, this technology lacks macroscopic shear force, has low emulsification efficiency for high-viscosity systems, and a long processing time, usually more than 10 minutes, resulting in high energy consumption per unit product, up to 1.5 kWh / kg. In addition, the existing preparation processes generally have problems of low energy utilization rate and low solvent recovery rate. The direct discharge of waste heat and organic solvents not only increases the production cost but also burdens the environment.

[0005] Therefore, the existing technology has deficiencies in realizing the industrial production of PHA emulsions with small particle sizes, high stability, low energy consumption, and low emissions. Summary of the Utility Model

[0006] The purpose of the utility model is to provide a PHA emulsification preparation device based on high-shear ultrasonic technology to solve the problems of large particle size, poor stability, low preparation efficiency, high energy consumption, and environmental pollution existing in the prior art.

[0007] To achieve the above purpose, the utility model adopts the following technical solutions:

[0008] A PHA emulsification preparation device based on high-shear ultrasonic technology includes a multi-channel feeding system, a high-shear ultrasonic mixing cavity, a temperature control unit, a discharging and on-line detection system, and an environmental protection and energy-saving module.

[0009] The multi-feed system is used to accurately convey multiple materials in a preset ratio. The system includes multiple independent feed channels, which are respectively connected to the PHA raw material tank, the emulsifier storage tank, the solvent tank, and the deionized water tank. A flow regulating device is provided on each feed channel to achieve precise control of the flow rate of each material, ensuring the accuracy of the material ratio before mixing.

[0010] The high-shear ultrasonic mixing cavity is connected to the outlet of the multi-feed system and is used for emulsifying the mixed materials. A high-speed rotating impeller and at least one ultrasonic transducer are coaxially arranged in the high-shear ultrasonic mixing cavity. The high-speed rotating impeller provides a strong macroscopic mechanical shear force, and its rotation speed can be set to 8000 - 10000 rpm. The blades are designed as serrated blades to enhance the shear effect, and their material is nitrided 316L stainless steel to improve wear resistance and service life. The ultrasonic transducer generates high-frequency vibrations and uses the ultrasonic cavitation effect to microscopically break droplets, and its working frequency can be set to 20 - 40 kHz. The synergistic effect of the high-speed rotating impeller and the ultrasonic transducer realizes the combination of macroscopic shear and microscopic fragmentation, and can refine the emulsion particle size to 100 - 200 nm within a short time (such as 3 - 5 minutes).

[0011] The temperature control unit is connected to the high-shear ultrasonic mixing cavity and is used to stabilize the emulsification temperature in the high-shear ultrasonic mixing cavity within the set process range, such as 40 - 80 °C. The unit includes a temperature sensor, a spiral heat exchange pipeline arranged outside the high-shear ultrasonic mixing cavity, and a proportional-integral-derivative (PID) temperature control module. Through precise temperature control, the emulsification reaction conditions are optimized and the materials are prevented from degrading due to overheating.

[0012] The discharge and on-line detection system is connected to the outlet of the high-shear ultrasonic mixing cavity. The system includes a centrifugal discharge pump for continuously discharging the finished emulsion and a laser scattering particle size detector integrated on the discharge pipeline. The detector can monitor the particle size distribution of the emulsion in real time.

[0013] This device may also include a particle size feedback controller. The particle size feedback controller is electrically connected to the laser scattering particle size detector to receive real-time particle size data, and is respectively electrically connected to the drive motor of the high-speed rotating impeller and the power supply of the ultrasonic transducer. When the detected particle size deviates from the set range, the particle size feedback controller can automatically adjust the rotation speed of the high-speed rotating impeller or the ultrasonic power to form a closed-loop control, thereby ensuring the uniformity and stability of the particle size of the finished emulsion. For example, when the detected particle size is greater than 200 nm, the particle size feedback controller can increase the rotation speed of the high-speed rotating impeller; when the detected particle size is less than 100 nm, the ultrasonic power can be reduced.

[0014] The environmental protection and energy-saving module is used to reduce the energy consumption and emissions of the device. The module includes a waste heat recovery device and a solvent recovery device.

[0015] The waste heat recovery device is connected to the heat exchange pipeline of the temperature control unit, recovering the waste heat generated during the emulsification process for preheating the materials entering the multi-channel feeding system, and the heat exchange efficiency can reach over 85%.

[0016] The solvent recovery device is connected to the high-shear ultrasonic mixing cavity for recovering the solvent vapor volatilized during the emulsification process. The device may include a first-stage condensation unit, a second-stage condensation unit, and an activated carbon adsorption tower connected in sequence. The recovered solvent can be returned to the solvent tank for recycling through the return pipeline after purification, and the solvent recovery rate can reach over 95%.

[0017] This device may also include a storage tank, which is connected downstream of the discharge and on-line detection system for collecting and storing the finally prepared qualified PHA emulsion.

[0018] Compared with the prior art, using a PHA emulsification preparation device based on high-shear ultrasonic technology of the present utility model can obtain the following beneficial effects:

[0019] High emulsification efficiency and good product performance: Through the synergistic effect of high shear and ultrasonic waves, combined with closed-loop feedback control, the particle size of the PHA emulsion can be refined to 100 - 200 nm within 3 - 5 minutes, with a uniform particle size distribution and good emulsion stability, and no obvious sedimentation or aggregation can be achieved within 30 days.

[0020] Energy-saving, environmental protection, and cost reduction: The integrated waste heat recovery device and solvent recovery device enable the waste heat recovery rate to reach over 85% and the solvent recovery rate to reach over 95%. Compared with the traditional high-shear process, the energy consumption per unit product can be reduced from 1.5 kWh / kg to 0.7 - 0.9 kWh / kg, with an energy-saving range of 40% - 50%, and at the same time, the emission of volatile organic compounds (VOCs) is significantly reduced.

[0021] High degree of automation and stable production: The on-line particle size detection and feedback control system realizes the automation of the production process, ensuring the batch stability and consistency of the product quality, and is suitable for industrial continuous production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present utility model provides the following drawings to more clearly show the structure of the device and its working principle.

[0023] Figure 1 : General structure schematic diagram of the PHA emulsification preparation device based on high-shear ultrasonic technology of the present utility model.

[0024] In the figure, 1 is a multi-channel feeding system; 1a is a feeding channel; 1b is a PHA raw material tank; 1c is an emulsifier storage tank; 1d is a solvent tank; 1e is a deionized water tank; 1f is a flow regulating device; 2 is a high-shear ultrasonic mixing cavity; 2a is a high-speed rotating impeller; 2a1 are serrated blades; 2b is an ultrasonic transducer; 2b1 is a threaded base; 3 is a temperature control unit; 3a is a temperature sensor; 3b is a heat exchange pipeline; 3c is a PID temperature control module; 4 is a discharging and on-line detection system; 4a is a centrifugal discharging pump; 4b is a laser scattering particle size detector; 4c is a discharging pipeline; 5 is an environmental protection and energy-saving module; 5a is a waste heat recovery device; 5b is a solvent recovery device; 5b1 is a first-stage condensation unit; 5b2 is a second-stage condensation unit; 5b3 is an activated carbon adsorption tower; 6 is a particle size feedback controller; 7 is a storage tank. Detailed implementation mode

[0025] The present utility model will be described in detail below in conjunction with specific embodiments. The embodiments are preferred implementation schemes and do not limit the protection scope of the present utility model.

[0026] Embodiment 1

[0027] Referring to Figure 1 , Embodiment 1 of the present invention provides a PHA emulsification preparation device based on high-shear ultrasonic technology.

[0028] The multi-channel feeding system 1 includes four independent feeding channels 1a, which are respectively connected to the PHA raw material tank 1b, the emulsifier storage tank 1c, the solvent tank 1d and the deionized water tank 1e. The feeding weight ratio of each material is set as PHA raw material: emulsifier: water: solvent = 10: 1: 20: 0.5. A flow regulating device 1f is provided on each feeding channel 1a, and its flow regulating accuracy is ±1%.

[0029] The effective volume of the high-shear ultrasonic mixing cavity 2 is 100L, the length-diameter ratio is 2: 1, and the inner wall roughness Ra ≤ 0.8μm. The rotation speed of the high-speed rotating impeller 2a in the high-shear ultrasonic mixing cavity 2 is set to 9000 rpm. It has 6 serrated blades 2a1, and the ratio of the diameter of the high-speed rotating impeller 2a to the inner diameter of the high-shear ultrasonic mixing cavity 2 is 0.8. The material of the high-speed rotating impeller 2a is 316L stainless steel treated by nitriding, and the surface hardness reaches 1100HV1. Three ultrasonic transducers 2b are fixed on the inner wall of the high-shear ultrasonic mixing cavity 2 through threaded bases 2b1 with anti-vibration rubber pads, and are evenly distributed circumferentially at 120°. The working frequency of the ultrasonic transducer 2b is 30 kHz, and the total power is 500W.

[0030] The temperature control unit 3 stably controls the temperature in the high-shear ultrasonic mixing cavity 2 at 60 ± 1 °C through a spiral copper heat exchange pipeline 3b and a PID temperature control module 3c.

[0031] The flow rate of the centrifugal discharge pump 4a in the discharge and on-line detection system 4 is set to 100 L / h. An on-line laser light scattering particle size detector 4b is integrated on the discharge pipe 4c, and its detection data is transmitted to the particle size feedback controller 6 through the RS485 interface.

[0032] The waste heat recovery device 5a in the environmental protection and energy saving module 5 recovers the waste heat of the high-shear ultrasonic mixing cavity 2 and is used to preheat the incoming deionized water. The measured heat exchange efficiency is 87%.

[0033] The inlet of the solvent recovery device 5b is connected to the top gas phase outlet of the high-shear ultrasonic mixing cavity 2 to collect the solvent vapor volatilized during the emulsification process. It includes a first-stage condensation unit 5b1 with a condensation temperature of -5°C, a second-stage condensation unit 5b2 with a condensation temperature of 8°C, and an activated carbon adsorption tower 5b3 with an activated carbon specific surface area of 1300 m² / g.

[0034] The qualified PHA emulsion discharged from the discharge and on-line detection system 4 flows into the storage tank 7 through a pipeline for collection.

[0035] Under these parameters, the emulsification time is 4 minutes. The experimental results show that the average particle size of the PHA emulsion in the stable operation state is 120 nm, and the particle size distribution is uniform. The sample is stored at room temperature for 30 days, and no obvious sedimentation phenomenon is observed. The energy consumption per unit product is 0.8 kWh / kg.

[0036] Example 2

[0037] In this Example 2, some parameters are adjusted based on Example 1.

[0038] The rotation speed of the high-speed rotating impeller 2a is increased to 10,000 rpm, and the total power of the ultrasonic transducer 2b is increased to 700 W. The feed ratio is adjusted to PHA raw material: emulsifier: water: solvent = 10:1:25:0.5. The flow rate of the centrifugal discharge pump 4a is adjusted to 120 L / h.

[0039] The particle size feedback controller 6 sets the control logic: when the on-line laser light scattering particle size detector 4b detects that the particle size is less than 100 nm, the total power of the ultrasonic transducer 2b is automatically reduced to 500 W, and the response time is 0.8 s.

[0040] After the environmental protection and energy saving module 5 is optimized, the waste heat recovery efficiency reaches 90%, and the solvent recovery rate reaches 97%.

[0041] The emulsification time is 3 minutes. The experimental results show that the average particle size of the PHA emulsion is reduced to 100 nm, and no particle aggregation phenomenon is observed in the 30-day storage test. The energy consumption per unit product is reduced to 0.7 kWh / kg.

[0042] Example 3

[0043] In this Embodiment 3, parameter adjustments are made for high-viscosity PHA raw materials.

[0044] The rotational speed of the high-speed rotating impeller 2a is adjusted to 8000 rpm, the frequency of the ultrasonic transducer 2b is adjusted to 40 kHz, and the total power is set to 600 W. The temperature control unit 3 stabilizes the temperature of the high-shear ultrasonic mixing cavity 2 at 70 ± 1 °C. The feeding ratio is adjusted to PHA raw material: emulsifier: water: solvent = 15:1.5:25:0.8. The flow rate of the centrifugal discharge pump 4a is set to 150 L / h.

[0045] The particle size feedback controller 6 sets the control logic: when the laser scattering particle size detector 4b detects that the particle size is greater than 200 nm, the rotational speed of the high-speed rotating impeller 2a is automatically increased to 10000 rpm, and the response time is 1 s.

[0046] The waste heat recovery efficiency of the environmental protection and energy-saving module 5 is 88%, and the solvent recovery rate is 96%.

[0047] The emulsification time is 4 minutes. The experimental results show that for high-viscosity raw materials, the average particle size of the prepared emulsion is 150 nm. The energy consumption per unit product is 0.9 kWh / kg.

[0048] Effect verification:

[0049] To verify the beneficial effects of the present utility model, the above embodiments are compared with the relevant performance parameters of the prior art, and the results are shown in Tables 1 and 2.

[0050] Table 1: Comparison of the particle size and stability of PHA emulsions between the embodiment and the traditional high-shear process.

[0051]

[0052] Table 2: Comparison of the key process parameters and environmental protection performance between the embodiment and the traditional high-shear process.

[0053]

[0054] Analyzing Tables 1 and 2, the following conclusions can be drawn:

[0055] 1. Analysis of technical performance advantages (based on Table 1):

[0056] Table 1 mainly shows the significant advantages of the present utility model in the core performance indicators of the product - emulsion particle size and stability.

[0057] Breakthrough progress in particle size control: Through Examples 1, 2, and 3 of the present utility model, the average particle sizes of the prepared PHA emulsions are 120 nm, 100 nm, and 150 nm respectively. In contrast, the particle sizes of emulsions prepared by traditional high-shear processes are generally in the range of 500 - 2000 nm. The data shows that the device of the present utility model has successfully reduced the particle size of the emulsion by more than one order of magnitude, achieving a leap from the micron scale to the nanoscale. This precise particle size control is the key to preparing high-performance emulsions and provides a basis for subsequent applications (such as forming a dense barrier coating).

[0058] Significant improvement in particle size distribution uniformity: The emulsions prepared by the present utility model have a "narrow" particle size distribution, which means that the particle sizes in the emulsion are highly consistent and have good uniformity. In contrast, the particle size distribution of products prepared by traditional high-shear processes is "wide", indicating that the particle sizes are different and the product uniformity is poor. A narrow particle size distribution is an important sign of high-quality emulsions, which ensures the stability and repeatability of product performance.

[0059] Fundamental improvement in the long-term stability of the product: In the 30-day storage stability test, the products of the three examples of the present utility model all showed "no obvious sedimentation" or "no obvious aggregation", demonstrating their excellent physical stability. This is in sharp contrast to the "significant sedimentation and aggregation" phenomenon that occurs in products prepared by traditional high-shear processes. Excellent storage stability not only extends the shelf life of the product, reduces the risk of failure during transportation and storage, but also ensures the reliability of product performance when used by end-users, and has important commercial application value.

[0060] 2. Analysis of production efficiency and environmental benefits (based on Table 2):

[0061] Table 2 shows the comprehensive advantages of the present utility model in industrial applications from three dimensions: process efficiency, energy consumption, and resource utilization.

[0062] Substantial improvement in production efficiency: The time required for the device to complete one emulsification process is only 3 - 4 minutes, much lower than the more than 10 minutes required by traditional high-shear processes. This means that within the same time, the production capacity of the device is at least 2 - 3 times that of traditional high-shear processes, significantly improving production efficiency and reducing time costs and the equipment depreciation cost per unit product.

[0063] Significant reduction in energy consumption: The energy consumption per unit product of the device is between 0.7 - 0.9 kWh / kg, while that of traditional high-shear processes is as high as 1.5 kWh / kg. Through calculation, the energy-saving range of the present utility model reaches 40% to 53%. The substantial reduction in energy consumption directly reduces the production and operation costs of enterprises, and at the same time reduces carbon emissions generated by energy consumption, with significant economic and environmental benefits.

[0064] Huge leap in resource recovery rate: The integrated environmental protection and energy-saving module of this utility model has remarkable effects. The waste heat recovery rate is as high as 87% - 90%, and the solvent recovery rate is as high as 96% - 97%. In the traditional high-shear process, these two indicators are usually below 50%. This shows that this device can efficiently recycle energy and materials, not only further reducing the raw material and energy costs, but also significantly reducing heat pollution and VOCs emissions from the source, fully meeting the requirements of modern green manufacturing and sustainable development.

[0065] In summary, through the detailed data analysis of Table 1 and Table 2, it can be seen that the "PHA emulsification preparation device based on high-shear ultrasonic technology" of this utility model is not a simple improvement of the existing technology, but a complete and advanced technical solution. Through the innovative design of the structure and control system, it has successfully overcome the bottlenecks of the existing technology in three core aspects: product performance, production efficiency, and environmental protection benefits, achieving an important breakthrough in PHA emulsion preparation technology.

[0066] The above is only the preferred embodiment of this utility model, and is not intended to limit the protection scope of this utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this utility model shall be included within the protection scope of this utility model.

Claims

1. A PHA emulsification preparation device based on high-shear ultrasonic technology, characterized in that, The device includes: A multi-channel feeding system (1), including multiple independent feeding channels (1a) and a flow regulating device (1f) connected thereto; A high-shear ultrasonic mixing cavity (2), connected to the outlet of the multi-channel feeding system (1), and a high-speed rotating impeller (2a) and an ultrasonic transducer (2b) are coaxially arranged in the high-shear ultrasonic mixing cavity (2); A temperature control unit (3), connected to the high-shear ultrasonic mixing cavity (2), including a temperature sensor (3a), a heat exchange pipeline (3b) and a PID temperature control module (3c); A discharging and on-line detection system (4), connected to the outlet of the high-shear ultrasonic mixing cavity (2); An environmental protection and energy-saving module (5), which includes a waste heat recovery device (5a) connected to the temperature control unit (3) and a solvent recovery device (5b) connected to the high-shear ultrasonic mixing cavity (2).

2. The device according to claim 1, wherein The multi-channel feeding system (1) includes at least four independent feeding channels (1a) respectively connected to a PHA raw material tank (1b), an emulsifier storage tank (1c), a solvent tank (1d) and a deionized water tank (1e), and a flow regulating device (1f) is provided in each feeding channel (1a).

3. The device according to claim 1, characterized in that, The blades of the high-speed rotating impeller (2a) are serrated blades (2a1), and the material of the high-speed rotating impeller (2a) is 316L stainless steel treated by nitriding.

4. The device according to claim 1, wherein The number of the ultrasonic transducers (2b) is three, and the three ultrasonic transducers (2b) are fixed to the inner wall of the high-shear ultrasonic mixing cavity (2) through a threaded base (2b1) with a vibration-proof rubber pad and are evenly distributed circumferentially at 120°.

5. The device according to claim 1, characterized in that, The temperature control unit (3) includes a spiral heat exchange pipeline (3b) arranged outside the high-shear ultrasonic mixing cavity (2) and a PID temperature control module (3c) connected to the heat exchange pipeline (3b).

6. The device according to claim 1, characterized in that, The discharging and on-line detection system (4) includes a centrifugal discharging pump (4a) and a laser scattering particle size detector (4b) integrated on the discharging pipeline (4c).

7. The device according to claim 6, characterized in that, The device further includes a particle size feedback controller (6), the particle size feedback controller (6) is electrically connected to the laser scattering particle size detector (4b), and is respectively electrically connected to the driving motor of the high-speed rotating impeller (2a) and the power supply of the ultrasonic transducer (2b).

8. The device according to claim 1, characterized in that, The solvent recovery device (5b) includes a first-stage condensation unit (5b1), a second-stage condensation unit (5b2) and an activated carbon adsorption tower (5b3) connected in sequence, and the outlet of the activated carbon adsorption tower (5b3) is connected to the solvent tank (1d) in the multi-channel feeding system (1) through a backfeed pipeline.

9. The device according to claim 1, characterized in that The device further includes a storage tank (7), the storage tank (7) is connected downstream of the discharging and on-line detection system (4) for collecting the finished emulsion.

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