阅读说明：本技术 一种气液两相强化混合制备纳米气泡分散液的方法 (Method for preparing nano-bubble dispersion liquid by intensive mixing of gas phase and liquid phase ) 是由 朱正曦 杨海宾 于 2021-08-30 设计创作，主要内容包括：本发明提出一种气液两相强化混合制备纳米气泡分散液的方法,将气相和液相两相流体高速射流流入混合器的闭合微腔体中,气相与液相在腔体中撞击并湍流混合,同时混合液与腔体壁面剧烈撞击,气相与液流及壁面在剧烈撞击和高剪切作用下被破碎、压缩,从而产生含纳米级气泡的分散液,分散液从混合器出口流出,完成纳米气泡分散液的制备。本发明能耗低、能效高、设备简单、无需高压气体而操作安全。有利于大大提高气液两相传质速率以提高气液两相反应速率、改善反应产物的选择性和收率。在化工反应、水产养殖、水污染治理、矿物浮选、清洗等众多领域也具有广阔的实际应用前景。(The invention provides a method for preparing nano bubble dispersion liquid by gas-liquid two-phase intensified mixing, which comprises the steps of enabling gas-phase and liquid-phase two-phase fluid high-speed jet flow to flow into a closed micro-cavity of a mixer, enabling the gas phase and the liquid phase to be impacted in the cavity and mixed in a turbulent flow mode, enabling mixed liquid to be violently impacted with the wall surface of the cavity, enabling the gas phase, the liquid flow and the wall surface to be broken and compressed under the action of violent impact and high shearing, generating the dispersion liquid containing nano bubbles, enabling the dispersion liquid to flow out from an outlet of the mixer, and completing the preparation of the nano bubble dispersion liquid. The invention has low energy consumption, high energy efficiency, simple equipment and safe operation without high-pressure gas. The method is favorable for greatly improving the gas-liquid two-phase mass transfer rate so as to improve the gas-liquid two-phase reaction rate and improve the selectivity and the yield of reaction products. The method has wide practical application prospect in chemical reaction, aquaculture, water pollution treatment, mineral flotation, cleaning and other fields.)

1. A method for preparing nano bubble dispersion liquid by gas-liquid two-phase intensified mixing is characterized in that: comprises the steps of (a) preparing a mixture of a plurality of raw materials,

and (2) enabling the gas-phase and liquid-phase two-phase fluid to flow into a micro-cavity of the mixer at a high speed, enabling the gas phase and the liquid phase to be impacted and turbulently mixed in the cavity, enabling the mixed liquid to be violently impacted with the wall surface of the cavity, enabling the gas phase to be violently impacted with the liquid flow and the wall surface, enabling the gas phase to be crushed and compressed under the action of high shear, and thus generating dispersion liquid containing nano-scale bubbles, and enabling the dispersion liquid to flow out of an outlet of the mixer to finish the preparation of the nano-bubble dispersion liquid.

2. The method for rapidly and easily preparing nanobubbles according to claim 1, wherein: the gas phase includes but is not limited to one or more of carbon dioxide, air, oxygen, nitrogen, hydrogen, olefin and other organic small molecule gases.

3. The method for rapidly and easily preparing nanobubbles according to claim 1, wherein: the liquid phase includes, but is not limited to, water and one or more of liquid organic solvents such as ketone, alcohol, ester, etc.

4. The method for rapidly and easily preparing nanobubbles according to claim 1, wherein: the mixer at least comprises a mixing micro-cavity, a gas-phase inflow port, a liquid-phase inflow port and a dispersion liquid outflow port.

5. The rapid and easy method for preparing nanobubbles according to claim 1 or 4, wherein: the mixer, the dispersion flowing out of it and the gas overflowing from the dispersion can be collected and re-flowed into the liquid-phase and gas-phase inflow ports, respectively.

6. The rapid and easy method for preparing nanobubbles according to claim 1 or 4, wherein: the mixed micro-cavity is a closed non-open cavity, and the volume of a single micro-cavity is less than or equal to 1 mL.

7. The rapid and easy method for preparing nanobubbles according to claim 1 or 4, wherein: the equivalent diameter of the gas phase inlet of the mixing micro-cavity is not more than 3 mm.

8. The method for rapidly and easily preparing nanobubbles according to claim 1, wherein: the sum of Reynolds numbers at the fluid inlets of the cavities is not less than 500.

9. The method for rapidly and easily preparing nanobubbles according to claim 1, wherein: the volume solubility of the gas phase in the liquid phase is not less than 1.7 vol%.

Technical Field

The invention belongs to the field of preparation of nano bubble dispersion liquid, and particularly relates to a method for instantly preparing nano bubbles.

Background

The gas-liquid two phases are generally poor in compatibility, the size of formed bubbles is large, and the bubbles are easy to float upwards to cause the size to increase in an accelerated mode and the bubbles to separate from each other quickly, so that the mixing degree of the gas-liquid two phases is low. However, many chemical reactions involve a gas-liquid two-phase mixing reaction, and the degree of two-phase mixing directly affects the selectivity and yield of the product. Achieving uniform mixing of the gas and liquid phases has long been a problem.

The nano bubbles have small size, large Brownian motion and difficult floating, so the nano bubbles can float in the dispersion liquid for a long time and have stable size. In addition, the nano bubbles have the advantages of large specific surface area, strong internal pressure of the bubbles, high gas content and the like, so that the mass transfer rate of gas-liquid two phases is high, and the reaction rate of the two phases is closer to the intrinsic reaction rate. In addition, the nano bubbles also have wide application prospects in various fields of chemical reaction, aquaculture, water pollution treatment, mineral flotation, cleaning and the like.

The conventional industrial preparation methods of the bubbles comprise a high-pressure gas explosion method, an ultrasonic cavitation method and the like, the methods have the defects of high energy consumption, low energy efficiency, high equipment cost, high operation pressure, low safety and the like, and the prepared bubbles have large average diameter and wide distribution. Therefore, the development of a novel method for preparing nano bubbles, which has the advantages of small diameter, narrow distribution, low energy consumption, high energy efficiency, simple equipment and operation, low pressure and safety, has important significance in promoting the wide application of nano bubbles.

Disclosure of Invention

This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions are not intended to limit the scope of the invention.

The present invention has been made keeping in mind the above problems occurring in the prior art.

Therefore, aiming at the defects of the prior art, the invention provides a novel method for simply and rapidly preparing nano bubbles, the method is safe, low in energy consumption, simple in device, easy to operate and continuous, and the prepared nano bubbles have the characteristics of small bubble size and excellent monodispersity.

To solve the above technical problem, according to an aspect of the present invention, the present invention provides the following technical solutions: a method for preparing nano bubble dispersion liquid by gas-liquid two-phase intensified mixing is characterized in that: comprises the steps of (a) preparing a mixture of a plurality of raw materials,

and (2) enabling the gas-phase and liquid-phase two-phase fluid to flow into a micro-cavity of the mixer at a high speed, enabling the gas phase and the liquid phase to be impacted and turbulently mixed in the cavity, enabling the mixed liquid to be violently impacted with the wall surface of the cavity, enabling the gas phase to be violently impacted with the liquid flow and the wall surface, enabling the gas phase to be crushed and compressed under the action of high shear, and thus generating dispersion liquid containing nano-scale bubbles, and enabling the dispersion liquid to flow out of an outlet of the mixer to finish the preparation of the nano-bubble dispersion liquid.

As a preferable scheme of the method for rapidly and simply preparing nanobubbles according to the present invention, wherein: the gas phase includes but is not limited to one or more of carbon dioxide, air, oxygen, nitrogen, hydrogen, olefin and other organic small molecule gases.

As a preferable scheme of the method for rapidly and simply preparing nanobubbles according to the present invention, wherein: the liquid phase includes, but is not limited to, water and one or more of liquid organic solvents such as ketone, alcohol, ester, etc.

As a preferable scheme of the method for rapidly and simply preparing nanobubbles according to the present invention, wherein: the mixer at least comprises a mixing micro-cavity, a gas-phase inflow port, a liquid-phase inflow port and a dispersion liquid outflow port.

As a preferable scheme of the method for rapidly and simply preparing nanobubbles according to the present invention, wherein: the mixer, the dispersion flowing out of it and the gas overflowing from the dispersion can be collected and flow into the liquid phase inflow port and the gas phase inflow port, respectively.

As a preferable scheme of the method for rapidly and simply preparing nanobubbles according to the present invention, wherein: the mixed micro-cavity is a closed non-open cavity, and the volume of a single micro-cavity is less than or equal to 1 mL.

As a preferable scheme of the method for rapidly and simply preparing nanobubbles according to the present invention, wherein: the equivalent diameter of the gas phase inlet of the mixing micro-cavity is not more than 3 mm.

As a preferable scheme of the method for rapidly and simply preparing nanobubbles according to the present invention, wherein: the sum of Reynolds numbers at the fluid inlets of the cavities is not less than 500.

As a preferable scheme of the method for rapidly and simply preparing nanobubbles according to the present invention, wherein: the volume solubility of the gas phase in the liquid phase is not less than 1.7 vol%.

The gas overflowing from the prepared nanobubble dispersion and from the dispersion may be collected and re-flowed into the liquid phase inflow port and the gas phase inflow port, respectively. So as to increase the utilization rate of the bubbles and the yield of the nano bubbles.

The micro-cavity used in the invention is a closed non-open cavity, and the volume of a single micro-cavity is less than or equal to 1 mL. The flowing gas and liquid are mixed in the small cavity with limited space and are violently collided with the wall surface of the cavity, the mixed liquid in the cavity obtains high energy density for dissipation, the dissipated energy is converted into gas-liquid interface energy, and the gas-liquid interface energy is used for compressing the gas, so that the nano-scale small bubbles are obtained. In addition, the small closed cavity can ensure that liquid flows in a turbulent way after entering the cavity, the liquid flowing in the turbulent way is easy to generate a vacuum cavitation phenomenon, and gas is absorbed and compressed by cavitation bubbles, so that nano-scale small bubbles are obtained.

The equivalent diameter of the gas phase inlet of the cavity is not more than 3mm, and the sum of Reynolds numbers of the fluid inlets of the cavity is not less than 500. So as to ensure that the gas phase flow is fine enough, and enters the cavity in a jet flow form to inject the liquid phase, thereby being beneficial to the shearing, thinning and breaking of the gas phase into fine bubbles by the turbulent liquid phase. The inlet total Reynolds number is large enough to ensure sufficient turbulent mixing of gas and liquid in the cavity, and high energy density dissipation, and the dissipated energy is converted into gas-liquid interfacial energy and used for compression of gas, so that nano-scale small bubbles are obtained.

The volume solubility of the gas phase used in the present invention in the liquid phase is not less than 1.7 vol%. It must have a certain solubility to ensure that the interface between the gas and liquid phases is not too high.

The preparation process of the invention comprises the following steps: and (2) enabling the gas-phase and liquid-phase two-phase fluid to flow into a micro-cavity of the mixer at a high speed, enabling the gas phase and the liquid phase to be impacted and turbulently mixed in the cavity, enabling the mixed liquid to be violently impacted with the wall surface of the cavity, enabling the gas phase, the liquid flow and the wall surface to be impacted and sheared to be crushed and compressed, and generating dispersion liquid containing nano-scale bubbles, and enabling the dispersion liquid to flow out of an outlet of the mixer to finish the preparation of the nano-bubble dispersion liquid.

The invention has the beneficial effects that:

the mixer used in the invention does not need moving parts, the energy consumption in the preparation process is low, but the energy density dissipation in the micro-cavity is high, and the efficiency of converting the energy into the interface energy of the bubbles is high. In addition, the mixing is instantly uniform, so the generated bubbles have small diameters and narrow distribution and are in the nanometer level. The method has the advantages of safety, low energy consumption, high energy efficiency, simple equipment, easy operation, continuity and high preparation speed, and the prepared nano bubbles have the characteristics of small size and narrow distribution.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise. Wherein:

FIG. 1 is a schematic diagram of a nano-bubble dispersion prepared by enhanced mixing of a gas phase and a liquid phase.

FIG. 2 is a graph showing the distribution of bubble diameters of an aqueous dispersion of carbon dioxide nanobubbles prepared by enhancing gas-liquid mixing using a micromixer.

FIG. 3 is a graph showing the stability of the average bubble particle size of a nanobubble aqueous dispersion of carbon dioxide and air prepared by enhancing gas-liquid mixing using a micromixer with respect to time.

FIG. 4 is a graph showing the distribution of bubble particle size of an aqueous dispersion of air nanobubbles prepared by enhancing gas-liquid mixing using a micromixer.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with examples are described in detail below.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

The volume of the micro-cavity of the mixer used in the embodiment of the invention is 1mL, and the equivalent diameter of the gas phase inlet is 3 mm.

The raw materials used in the present invention are all commercially available unless otherwise specified.

Example 1:

preparation of carbon dioxide nanobubble aqueous dispersion (using carbon dioxide gas and degassed water) by micro-mixer intensified gas-liquid mixing method

50mL of water was sonicated for 10 minutes to remove dissolved gases.

The volume solubility of carbon dioxide in water at 25 ℃ was 75.9 vol%. Introducing carbon dioxide gas into a gas phase inflow port of a micro-cavity of the mixer, simultaneously introducing 50mL of degassed water into a liquid phase inflow port of the micro-cavity of the mixer, injecting the carbon dioxide phase into the water phase in the cavity at a high speed, wherein the flow rate of the gas phase inflow port of the micro-cavity is 100mL/min, the flow rate of the liquid phase inflow port of the micro-cavity is 100mL/min, the total Reynolds number Re is 2000, mixing two phases of turbulent flows, and shearing, crushing and compressing the gas phase of the cavity to generate tiny bubbles.

The carbon dioxide bubble dispersion liquid discharged from the mixer was collected, left to stand for half an hour, and the average diameter of the bubbles was measured by a dynamic light scattering instrument to be 301nm, the size polydispersity index was measured to be 0.4 (note: 0 represents a single diameter, and 1 represents an infinite wide size distribution), and the bubble size distribution was shown in FIG. 2. The diameter of the bubble is in the nanometer level, and the bubble is a nanometer bubble with smaller size. The measurement of bubble size stability using a dynamic light scattering instrument (as shown in FIG. 3) indicates that the average bubble diameter can be maintained at the nanoscale for at least 5 hours.

Example 2:

comparison of aeration method with micromixer intensified gas-liquid mixing method for preparing bubble dispersion (using carbon dioxide gas and degassed water)

50mL of water is taken to remove dissolved gas in the water by ultrasonic treatment for 10 minutes, carbon dioxide with 3 atmospheres of pressure is introduced into the degassed water at 25 ℃, and the gas is exploded for 10 minutes under high-pressure airflow. And (3) after the gas explosion is finished, standing the bubble dispersion liquid for half an hour, and measuring the average diameter of the bubbles by using a dynamic light scattering instrument to be 6.0 mu m and the size polydispersity index to be 0.8. The average diameter of the bubbles prepared by the explosion method is micron-sized, is far larger than that of the nano bubbles prepared by the micro mixer enhanced gas-liquid mixing method in the embodiment 1, and the size distribution is very wide and far larger than that of the embodiment 1.

Example 3:

micro mixer for preparing carbon dioxide microbubble water dispersion (using carbon dioxide gas and carbon dioxide saturated water)

50mL of water is introduced and carbon dioxide is bubbled slowly for 10 minutes to saturate the carbon dioxide dissolved in the water, and the mixture is kept stand for half an hour.

The carbon dioxide gas further has a volumetric solubility of approximately 0 in carbon dioxide saturated water at 25 ℃. Introducing carbon dioxide gas into a gas inflow port of the micro-cavity of the mixer, simultaneously introducing the 50mL of saturated carbon dioxide aqueous solution into a liquid inflow port of the micro-cavity of the mixer, injecting the carbon dioxide phase into the water phase in the cavity at a high speed, wherein the gas phase inlet flow rate of the micro-cavity is 100mL/min, the water phase inlet flow rate of the micro-cavity is 100mL/min, the total Reynolds number Re is 2000, mixing the two phases in a turbulent manner, and shearing, fragmenting and dispersing the cavity gas phase in the water phase.

The carbon dioxide bubble dispersion liquid flowing out of the mixer was collected, left to stand for half an hour, and the average diameter of the bubbles was 2.1 μm and the size polydispersity index was 0.9 as measured by a dynamic light scattering instrument. The average diameter of the bubbles is micron-sized, which is much larger than the average diameter of the nano bubbles obtained in example 1, and the size distribution is very wide, which is much larger than that of example 1. This example illustrates that the gas phase needs to have some solubility in the liquid phase prior to mixing, and in this example the ability of a saturated aqueous carbon dioxide solution to continue dissolving carbon dioxide gas at atmospheric pressure is extremely limited and cannot effectively form nano-scale bubbles.

Example 4:

micro mixer for preparing air nano bubble water dispersion (using air and deaerated water) by strengthening gas-liquid mixing

50mL of water was sonicated for 10 minutes to remove dissolved gases.

The volume solubility of air in water at 25 ℃ was 1.7 vol%. Air is introduced into a gas phase inflow port of the micro-cavity of the mixer, simultaneously 50mL of degassed water is introduced into a liquid phase inflow port of the micro-cavity of the mixer, the air phase in the cavity is jetted at high speed to flow into a water phase, the gas phase inlet flow rate of the micro-cavity is 100mL/min, the water phase inlet flow rate of the micro-cavity is 100mL/min, the total Reynolds number Re is 2000, two phases are mixed in a turbulent way, and the gas phase in the cavity is sheared and cracked to generate bubbles.

The air bubble dispersion liquid flowing out of the mixer was collected, left to stand for half an hour, and the average diameter of the bubbles was 860nm and the size polydispersity index was 0.93 as measured by a dynamic light scattering instrument, and the bubble size distribution and stability were measured by a dynamic light scattering instrument, and the results are shown in FIG. 4. The average diameter of the bubbles increased to 998nm after about 2.5 hours, as shown in FIG. 3, still slightly less than 1.0 μm. Close to an average diameter of 1.0 μm and reached 1.0 μm in a shorter time than the gas bubbles in example 1, the critical size and stability showed that the volume solubility of the gas was 1.7 vol% which was close to the critical solubility.

Example 5:

preparation of isobutylene nanobubble ethyl acetate dispersion (using isobutylene gas and ethyl acetate) by micro-mixer intensified gas-liquid mixing method

The volume solubility of isobutylene in ethyl acetate solvent at 25 ℃ was 6066 vol%.

50mL of ethyl acetate were taken and isobutylene gas was bubbled slowly through the ethyl acetate, which was weighed to ensure that 8.7g (3.0L) of isobutylene gas was dissolved. The solubility of isobutene in the above-mentioned solution of isobutene in ethyl acetate was 66 vol%. Isobutene gas is led into a gas phase inlet of a micro-cavity of the mixer, meanwhile, 50mL of isobutene ethyl acetate solution is led into a liquid phase inlet of the micro-cavity of the mixer, isobutene gas phase in the cavity is jetted into the ethyl acetate solution phase at a high speed, the flow rate of the micro-cavity gas phase inlet is 100mL/min, the micro-cavity liquid phase inlet is 100mL/min, the total Reynolds number Re is 4100, two phases are mixed in a turbulent mode, and the cavity gas phase is sheared, cracked and compressed to generate tiny bubbles.

The ethyl acetate dispersion of the isobutene bubbles which flowed out of the mixer was collected, left for half an hour, and the average diameter of the bubbles was 390nm and the size polydispersity index was 0.3, as measured using a dynamic light scattering instrument. The diameter of the bubble is at the nanometer level and is a nanometer bubble.

The mixer used in the invention does not need moving parts, and the energy consumption in the preparation process is low. In addition, the mixing is instantly uniform, so the generated bubbles have small diameters and narrow distribution and are in the nanometer level. The method has the advantages of safety, low energy consumption, simple equipment, easy operation, continuity and high preparation speed, and the prepared nano bubbles have the characteristics of small size and narrow distribution.

It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.