CN115845423A - Device and method for strengthening gas-liquid mass transfer by utilizing local circulation and bubble cyclone - Google Patents

Abstract

The invention provides a device and a method for strengthening gas-liquid mass transfer by utilizing local circulation and bubble cyclone, which comprises a plurality of stages of mass transfer units connected in series, wherein each stage of mass transfer unit comprises a cyclone negative pressure cavity and a bubble cyclone cavity which are mutually connected and vertical in the axial direction, a liquid inlet is arranged at the tangential direction of the cyclone negative pressure cavity, a gas inlet is arranged at one axial end, and a jet orifice communicated with the bubble cyclone cavity at the tangential direction is arranged at the other axial end; the bubble rotational flow cavity is tangentially provided with a liquid outlet, the bubble rotational flow cavity is axially provided with a gas outlet, and the gas outlet is connected with the gas inlet through a circulating pipeline. Liquid and gas are injected in the first-stage mass transfer unit, gas-liquid cyclone separation is realized in the last-stage mass transfer unit, each mass transfer unit has a gas circulation function and a gas bubble stage separation function, efficient gas-liquid mass transfer is realized, and the gas-liquid cyclone separator is suitable for chemical reaction and separation processes.

Description

A device and method for enhancing gas-liquid mass transfer using partial circulation and bubble swirl

technical field

The invention belongs to the technical field of chemical reaction and separation, and in particular relates to a device and method for enhancing gas-liquid mass transfer by utilizing partial circulation and bubble swirl flow.

Background technique

Common methods to enhance gas-liquid mass transfer include introducing an external energy field, enhancing gas-liquid mass transfer with dispersed phase particles, and improving two-phase flow and contact. Among them, CN201310483586.7 discloses a magnetic field enhanced gas-liquid mass transfer device, and CN201510610452.6 discloses a rotating packed bed mass transfer and reaction equipment, but the external energy field such as magnetic field, electric field will lead to additional energy consumption and operation Complexity. CN201510406070.1 discloses a device for strengthening the gas-liquid mass transfer of a bubbling bed hydrogenation reactor, which mainly adopts the method of adding a surfactant to reduce the rising speed of the bubbles, thereby increasing the stability time of the bubbles in the oil, The gas-liquid mass transfer is enhanced, but the dispersed phase particles usually cause the secondary pollution of the fluid, making it difficult to apply on a large scale in industrial production.

Improving two-phase flow and contact is the main means of enhancing mass transfer in industrial production. CN200910188141.X discloses a method for enhancing gas-liquid mass transfer in ebullating bed hydrogenation reactors, so that hydrogen is dispersed in liquid phase materials in the form of microbubbles , improve the utilization rate of hydrogen and reduce the volume ratio of hydrogen to oil. It is a consensus in the field of traditional chemical engineering to reduce the bubble size to achieve enhanced mass transfer. However, when the bubbles enter the large-scale tower reactor, problems such as coalescence, deformation, and uneven distribution will occur, resulting in certain limitations in gas-liquid mass transfer. On this basis, methods such as gas-liquid redistribution in the tower have appeared. CN200510127803.4 discloses a method of vapor-liquid mass transfer without amplification effect. Multiple mass transfer elements are installed in parallel on a layer of trays. CN200510125698.0 A high-speed vapor-liquid mass transfer component is disclosed, which improves the uneven distribution of vapor-liquid in the packed tower and strengthens the mass transfer process. Tower internals are an important part of the current development of enhanced gas-liquid mass transfer, which makes the complexity of the tower equipment increase, the continuous operation period of the device is shortened. Subsequently, methods and devices for replacing tower-type gas-liquid mass transfer reactions have appeared one after another. CN201410109267.4 discloses a method for strengthening the gas-liquid process in a microreactor, which realizes efficient mass transfer reactions in microchannels, but in large processing There are limitations in the application of quantitative working conditions.

Therefore, it is of great significance to find a new method for enhancing gas-liquid mass transfer to overcome the above-mentioned problems in the prior art.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a device and method for enhancing gas-liquid mass transfer by using local circulation and bubble swirl, on the one hand, the circulation of gas in the swirl unit is realized by using swirl negative pressure, on the other hand On the one hand, the bubble swirl is used to achieve enhanced mass transfer, and the gas-liquid mass transfer is enhanced by combining local circulation and bubble swirl.

The present invention is achieved through the following technical solutions:

A device for enhancing gas-liquid mass transfer using local circulation and bubble swirl flow, the device for enhancing gas-liquid mass transfer includes several stages of mass transfer units connected in series, the number of stages is ≥ 1, wherein:

Each stage of mass transfer unit includes a swirl negative pressure chamber and a bubble swirl chamber connected in one body and the axial direction is perpendicular to each other. The tangential direction of the swirl negative pressure chamber is provided with a liquid inlet, and one end of the axial direction is provided with a gas inlet. One end is provided with an injection port communicating with the bubble swirl chamber and arranged tangentially with the bubble swirl chamber; a liquid outlet is arranged tangentially in the bubble swirl chamber, and a gas outlet is arranged axially, and the gas outlet is connected to the air bubble swirl chamber. The gas inlet is connected through a circulation pipeline; the liquid outlet is connected with the liquid inlet of the next-stage mass transfer unit or used as the liquid outlet of the last-stage mass transfer unit for the liquid phase discharge of the device.

K的范围为4～12，以实现合适的负压性能，其中D₁为旋流负压腔的直径，d₀为喷射口的当量直径，d_in为液体进口的当量直径。In the present invention, it is further set that each stage of mass transfer unit has a gas circulation function, and the structural parameters of the cyclone negative pressure chamber

K ranges from 4 to 12 to achieve suitable negative pressure performance, where D ₁ is the diameter of the swirl negative pressure chamber, d ₀ is the equivalent diameter of the injection port, and d _in is the equivalent diameter of the liquid inlet.

The present invention is further provided that the ratio of the equivalent diameter d _in of the liquid inlet to the diameter D ₁ of the swirl negative pressure chamber is 0.2-0.5, preferably 0.2-0.3; the equivalent diameter d ₀ of the injection port is in the range of The ratio of the diameter _D1 of the cyclone negative pressure chamber is 0.2-0.5, preferably 0.2-0.3.

In the present invention, it is further set that the bubble swirl chamber of each stage of mass transfer unit has the function of realizing gas-liquid mass transfer and bubble fractionation and separation through the bubble swirl, and the diameter of the bubble swirl chamber is the same as that of the swirl negative pressure chamber. The ratio of the diameters is 1.5-3; the size of the bubbles in each mass transfer unit tends to decrease compared with the previous mass transfer unit, and the diameter of the bubble swirl chamber decreases as the number of series series increases.

The present invention is further provided that the ratio of the equivalent diameter of the liquid outlet to the equivalent diameter of the injection port is 0.8-2, preferably 0.8-1.2.

The present invention also provides a method for enhancing gas-liquid mass transfer, using the above-mentioned device for enhancing gas-liquid mass transfer by utilizing local circulation and bubble swirl, the method includes:

The liquid and gas enter the swirl negative pressure chamber of the first-stage mass transfer unit to form a swirl field, and form multi-scale bubbles at the injection port. After entering the swirl mass transfer in the bubble swirl chamber, the larger bubbles migrate to A gas column is formed at the central position, and the gas column gas is circulated from the circulation pipeline to the gas inlet of the first-stage mass transfer unit, and the smaller air bubbles that have not migrated to the central position are discharged from the liquid outlet along with the liquid and passed into the next-stage mass transfer unit The liquid inlet of the unit and the gas inlet of the next-stage mass transfer unit come from the circulating gas discharged from the gas outlet of the mass transfer unit of this stage; repeat to the last stage, the gas part discharged from the gas outlet of the last-stage mass transfer unit Circulate to the gas inlet of the mass transfer unit at this stage, part of it is discharged, and the liquid is discharged from the liquid outlet to obtain the gas and liquid after mass transfer treatment.

The present invention is further configured that, in each stage of mass transfer unit, the ratio of the volume flow rate of liquid to gas is 1-1000; the speed at which liquid is injected into the liquid inlet in the first-stage mass transfer unit is 4-11 m/s .

In the present invention, it is further set that the centrifugal acceleration of the liquid in the swirl negative pressure chamber is 100-2000 times of the acceleration of gravity.

In the present invention, it is further configured that the average flow velocity of the gas at the gas outlet is in the range of 0.2-10 m/s.

The present invention is further configured that the device for enhancing gas-liquid mass transfer can be heated or condensed to achieve a higher efficiency mass transfer process.

Compared with prior art, the beneficial effect of the present invention is:

The invention provides a device and method for enhancing gas-liquid mass transfer by using partial circulation and bubble swirl. On the one hand, the negative pressure of the swirl is used to realize the gas circulation in the swirl unit; Combining partial circulation and bubble swirl to enhance gas-liquid mass transfer, and organically combining a single gas-liquid mass transfer unit, each mass transfer unit has the function of gas circulation and bubble fractionation, realizing efficient gas-liquid mass transfer It is widely used in chemical reaction and separation process.

Description of drawings

Figure 1 is a device for enhancing mass transfer without a multi-stage cyclone unit with partial circulation;

Figure 2 is a device for enhancing gas-liquid mass transfer using partial circulation and bubble swirl;

Fig. 3 is the structural representation of single mass transfer unit;

Among them, 1-liquid inlet, 2-gas inlet, 3-swirl negative pressure chamber, 4-jet port, 5-bubble swirl chamber, 6-gas outlet, 7-liquid outlet, 8-circulation pipeline.

Detailed ways

Below in conjunction with embodiment the present invention is described in further detail. It should be understood that the following examples are only used to further illustrate the present invention, and should not be interpreted as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art according to the contents of the present invention still belong to protection scope of the present invention.

There is a pressure gradient field in the swirling flow field, which shows the distribution characteristics of high side wall pressure and low center pressure, but it is not known exactly how low the center pressure is. The applicant has found through research that there is a lower pressure in the central region of the cyclone than the liquid outlet, and the lowest negative pressure is about -0.25 times the feed pressure. At the same time, the applicant has provided a method for enhancing mass transfer in a multi-stage cyclone unit as shown in Figure 1 through research. Gas and liquid are injected into a multi-stage cyclone unit, and the gas and liquid after mass transfer in a cyclone unit are The liquid flows to the next cyclone unit to repeat the operation, but this is a typical two-phase co-current flow, and usually the gas velocity is greater than the liquid velocity, so that the bubbles and the liquid are not in full contact, which is not conducive to mass transfer. On the one hand, the present invention utilizes swirl negative pressure to realize gas circulation in the swirl unit, on the other hand, utilizes bubble swirl to realize enhanced mass transfer, combines local circulation and bubble swirl to enhance gas-liquid mass transfer, and separates individual gas-liquid The mass transfer unit is organically combined to achieve efficient gas-liquid mass transfer.

Example 1

A device for enhancing gas-liquid mass transfer using partial circulation and bubble swirl flow of the present invention, as shown in Figure 2, includes a number of mass transfer units connected in series, with a single mass transfer unit as the core, and i stages are connected in series along the liquid flow direction (i≥1), liquid and gas are injected in the first-stage mass transfer unit, and gas-liquid separation is realized in the last-stage mass transfer unit; as shown in Figure 3, a single mass transfer unit includes a cyclone negative pressure connected together chamber 3 and a bubble swirl chamber 5, the swirl negative pressure chamber 3 and the bubble swirl chamber 5 are cylindrical cavities perpendicular to each other in the axial direction, and the tangential direction of the swirl negative pressure chamber 3 is provided with a liquid inlet 1, One axial end is provided with a gas inlet 2, and the other end is provided with an injection port 4 communicating with the bubble swirl chamber 5 as a tangential inlet of the bubble swirl chamber 5; the tangential arrangement of the bubble swirl chamber 5 A liquid outlet 7, a gas outlet 6 is arranged axially upward, the gas outlet 6 is connected to the gas inlet 2 through a circulation line 8, and the liquid outlet 7 is connected to the liquid inlet 1 of the next-stage mass transfer unit or used as the The outlet of the device is used for liquid discharge.

The liquid and gas to be gas-liquid mass transfer enter the swirl negative pressure chamber 3 of the first-stage mass transfer unit through the liquid inlet 1 and the gas inlet 2 respectively to form a swirl field, and form a multi-scale flow at the injection port 4. Bubbles, after entering the bubble swirl cavity 5 for swirling mass transfer, larger bubbles migrate to the central position to form a gas column, the pressure at the gas inlet 2 is lower than the pressure at the gas outlet 6, and the gas column gas passes through the The gas outlet 6 is circulated to the gas inlet 2 of the first-stage mass transfer unit by the circulation line 8, and the small bubbles that have not migrated to the central position are discharged from the liquid outlet 7 along with the liquid, and then pass into the liquid inlet 1 of the next-stage mass transfer unit , the intake air at the gas inlet 2 of the next-stage mass transfer unit comes from the circulating gas discharged from the gas outlet 6 of the mass transfer unit at this stage; After the bubble swirling action, the gas discharged from the gas outlet 6 is partially circulated to the gas inlet 2 of the mass transfer unit of the current stage, and part of it is discharged, and the liquid is discharged from the liquid outlet 7, so as to realize the separation of fine bubbles and liquid, and obtain the gas after mass transfer treatment. and liquid.

计算，其中D₁为旋流负压腔3的直径，d₀为喷射口4的当量直径，d_in为液体进口1的当量直径；所述旋流负压腔3的液体离心加速度为重力加速度的100～2000倍。Further, each stage of mass transfer unit has a gas circulation function, the pressure at the gas inlet 2 is lower than the pressure at the gas outlet 6, and is communicated through the circulation line 8, and the circulation line 8 should be as short as possible ; The structural parameter K of the swirl negative pressure chamber 3 ranges from 4 to 12 to achieve suitable negative pressure performance, and the structural parameter K is based on

Calculate, wherein D ₁ is the diameter of the swirl negative pressure chamber 3, d ₀ is the equivalent diameter of the injection port 4, and d _in is the equivalent diameter of the liquid inlet 1; the liquid centrifugal acceleration of the swirl negative pressure chamber 3 is the acceleration of gravity 100-2000 times of that.

Further, the ratio of the equivalent diameter d _in of the liquid inlet 1 to the diameter D 1 of the swirl negative pressure chamber ₃ is 0.2-0.5, preferably 0.2-0.3; the equivalent diameter d ₀ of the injection port 4 is in the range of The ratio of the diameter _D1 of the cyclone negative pressure chamber 3 is 0.2-0.5, preferably 0.2-0.3.

Further, the bubble swirl cavity 5 of each stage of mass transfer unit has the functions of realizing gas-liquid mass transfer and bubble fractionation through the bubble swirl, and the diameter _D of the bubble swirl cavity 5 is related to the negative pressure of the swirl. The ratio of the diameter D ₁ of the cavity 3 is 1.5-3; preferably, the diameter D ₂ of the bubble swirl cavity 5 is in the range of 20-100 mm.

Further, the diameter of the gas outlet 6 should be such that the average velocity of the gas at the outlet is in the range of 0.2-10 m/s.

Further, the ratio of the equivalent diameter d _out of the liquid outlet 7 to the equivalent diameter d ₀ of the injection port 4 is 0.8-2, preferably 0.8-1.2.

Further, the bubble size of each mass transfer unit tends to decrease compared with the previous mass transfer unit, and the diameter D ₂ of the bubble swirl chamber 5 decreases as the number of series series increases.

Further, in each mass transfer unit, the volumetric flow rate ratio of the liquid to the gas is 1-1000; the speed at which the liquid is injected into the liquid inlet 1 in the first-stage mass transfer unit is 4-11 m/s.

Further, the device for enhancing gas-liquid mass transfer can be heated or condensed to achieve a more efficient mass transfer process.

Example 2

Using the air-water system, oxygenation experiments were carried out on low-oxygen water to test the enhanced mass transfer effect from gas to liquid. The bubble cyclone device without local circulation as shown in Figure 1 and the device using local circulation and bubble cyclone to strengthen gas-liquid mass transfer as described in Example 1 were respectively adopted, and the dissolved oxygen concentration of low-oxygenated water was 2 mg/ L, experimental parameters and results are shown in the table below.

The bubble cyclone device without partial circulation can increase the dissolved oxygen concentration of low-oxygenated water to 6 mg/L, while the bubble cyclone device with partial circulation described in Example 1 can increase the dissolved oxygen concentration of low-oxygenated water to 10mg/L, which greatly improves the dissolved oxygen rate in water, and significantly improves the mass transfer effect from gas to liquid. It is a closed and efficient gas-liquid mass transfer method.

Example 3

A nitrogen-water system was used to conduct a deoxygenation experiment on highly oxygenated water to test the enhanced mass transfer effect from liquid to gas. The bubble cyclone device without local circulation as shown in Figure 1 and the device using local circulation and bubble cyclone to strengthen gas-liquid mass transfer as described in Example 1 were respectively adopted, and the dissolved oxygen concentration of the highly oxygenated water was 10 mg/ L, experimental parameters and results are shown in the table below.

The bubble cyclone device without partial circulation reduces the dissolved oxygen concentration of highly oxygenated water to 8 mg/L, while the bubble cyclone device with partial circulation described in Example 1 can reduce the dissolved oxygen concentration of highly oxygenated water To 5mg/L, significantly improved the mass transfer effect of liquid to gas.

This application has made a detailed description, the purpose of which is to enable those skilled in the art to understand and implement the content of this application, and not to limit the scope of protection of this application. Effect changes or modifications should be covered within the protection scope of the present application.

Claims (9)

1. The device for strengthening gas-liquid mass transfer by utilizing local circulation and bubble cyclone is characterized by comprising a plurality of stages of mass transfer units connected in series, wherein the stage number is more than or equal to 1,

each stage of mass transfer unit comprises a rotational flow negative pressure cavity and a bubble rotational flow cavity which are connected into a whole and are mutually vertical in the axial direction, wherein a liquid inlet is arranged at the tangential direction of the rotational flow negative pressure cavity, a gas inlet is arranged at one axial end of the rotational flow negative pressure cavity, and a jet orifice which is communicated with the bubble rotational flow cavity and is arranged at the tangential direction of the bubble rotational flow cavity is arranged at the other axial end of the rotational flow negative pressure cavity; the bubble rotational flow cavity is tangentially provided with a liquid outlet and axially provided with a gas outlet, and the gas outlet is connected with the gas inlet through a circulating pipeline; the liquid outlet is communicated with the liquid inlet of the next-stage mass transfer unit or is directly used for discharging the liquid phase of the device when being used as the liquid outlet of the last-stage mass transfer unit.

2. The apparatus for enhancing gas-liquid mass transfer of claim 1, wherein the structural parameters of said swirling negative pressure chamber

K ranges from 4 to 12, wherein D ₁ Is the diameter of the swirling negative pressure chamber, d ₀ Is the equivalent diameter of the ejection orifice, d _in Is the equivalent diameter of the liquid inlet.

3. The enhanced gas-liquid mass transfer device of claim 1, wherein the ratio of the equivalent diameter of the liquid inlet to the diameter of the swirling negative pressure chamber is 0.2 to 0.5, preferably 0.2 to 0.3; the ratio of the equivalent diameter of the injection port to the diameter of the swirling flow negative pressure chamber is 0.2 to 0.5, preferably 0.2 to 0.3.

4. The mass transfer enhancement device for a gas-liquid as recited in claim 1, wherein a ratio of a diameter of the bubble swirling chamber to a diameter of the swirling negative pressure chamber is 1.5 to 3; the diameter of the bubble vortex chamber decreases with the increase of the series stage number.

5. The apparatus for enhanced gas-liquid mass transfer according to claim 1, wherein the ratio of the equivalent diameter of the liquid outlet to the equivalent diameter of the injection orifice is 0.8 to 2, preferably 0.8 to 1.2.

6. A method for enhancing gas-liquid mass transfer using the apparatus for enhancing gas-liquid mass transfer using partial circulation and bubble cyclone of any one of claims 1 to 5, comprising:

liquid and gas enter a cyclone negative pressure cavity of a first-stage mass transfer unit to form a cyclone field, multi-scale bubbles are formed at the injection port, after entering the bubble cyclone cavity for cyclone mass transfer, larger bubbles migrate to the central position to form a gas column, gas in the gas column circulates to a gas inlet of the first-stage mass transfer unit through the circulating pipeline, smaller bubbles which do not migrate to the central position are discharged from a liquid outlet along with the liquid and are introduced into a liquid inlet of a next-stage mass transfer unit, and gas inlet at the gas inlet of the next-stage mass transfer unit is from circulating gas discharged from a gas outlet of the current-stage mass transfer unit; and repeating to the last stage, wherein part of gas discharged from the gas outlet of the last stage mass transfer unit is circulated to the gas inlet of the mass transfer unit, part of the gas is discharged, and the liquid is discharged from the liquid outlet, so that the gas and the liquid after mass transfer treatment are obtained.

7. The process of claim 6 wherein the ratio of the volumetric flow rates of liquid and gas in each stage of the mass transfer unit is from 1 to 1000; the speed of liquid injected into the liquid inlet in the first-stage mass transfer unit is 4-11 m/s.

8. The method of claim 6, wherein the centrifugal acceleration of the liquid in the swirling negative pressure chamber is 100 to 2000 times of the gravitational acceleration.

9. The method of claim 6, wherein the average flow velocity of the gas at the gas outlet is in the range of 0.2 to 10 m/s.

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