A gas-feeding reaction and separation coupling device and method for enhancing countercurrent mass transfer

Abstract

The present invention discloses a gas-feeding reaction and separation coupling device and method for enhanced countercurrent mass transfer. The present invention achieves more efficient utilization of the effective components and molecular motion dynamics in the gas feed through the organic combination of gas-feeding mass separation, regionalized feeding, solid-phase drag separation, rational utilization of fluid dynamics, optimized control of reaction kinetics, and enhanced mass transfer. Micronized bubbles are used for countercurrent contact with wastewater, increasing the frequency of gas-liquid contact, enhancing the efficiency of mass transfer and reaction, and improving the mineralization level of wastewater treatment. The reaction zone and separation zone are integrated and coupled to achieve in-situ separation of sludge by properties. This model of invention is suitable for the design of advanced oxidation and advanced biological treatment reactors for wastewater using ozone catalytic oxidation with catalyst addition and biologically activated sludge (anaerobic, aerobic, and hydrolysis).

Description

Technical Field

[0001] The present invention relates to the field of sewage and wastewater treatment, and in particular to a gas-material addition reaction and separation coupling device and method for enhancing countercurrent mass transfer. Background Art

[0002] In traditional wastewater treatment reactors, the contact between gas and wastewater is relatively simple. In typical reactors, the gas and liquid phases react in the same direction, resulting in insufficient contact between the gas and wastewater. This limits the efficiency of the mass transfer process between the gas and pollutants in the wastewater, resulting in high treatment energy consumption and affecting wastewater treatment costs. Therefore, the question is how to leverage the principles of fluid mechanics to enhance the interphase mass transfer between gas, liquid, and solid, improve the utilization rate of the gas, and enhance the technical efficiency of the entire process.

[0003] Compared with the traditional bottom aeration sewage treatment reactor device, the current research hotspot is concentrated on the uniform distribution of gas and material in the reactor and the application of microbubbles. The gas transmission methods in the reactor can be divided into two types. First, the use of porous plates loaded with silica sand filling layers to evenly distribute the gas-liquid flow rate and the effective regulation of gas-liquid by circulation in the fluidized bed to achieve uniform distribution of gas and material. Second, the microbubble generating device was coupled with a conventional cylindrical reactor, and it was found that compared with large bubbles (average diameter 1mm), microbubbles (average diameter <45μm) showed higher organic matter removal efficiency. The main reason is that microbubbles can increase the gas-liquid contact specific surface area, enhance the internal vapor pressure of the bubbles, and prolong the gas-liquid contact time. At the same time, compared with conventional bubbles, at the same gas flow rate, the volume mass transfer coefficient of microbubbles increased by 32.59%. Generally speaking, for traditional bubbling gas-liquid two-phase or gas-liquid-solid three-phase reactions, the reaction mechanism and kinetics of the gas feed and pollutants are inherently limited by the hydrodynamic behavior of the front-end gas within the reactor, including uniform and orderly gas movement, hydraulic residence time, gas-liquid mass transfer, and bubble stability (coalescence). The inventors believe that it is possible to overcome these limitations of hydrodynamic behavior by focusing on extending the hydraulic residence time of bubbles in the reactor and fully utilizing fluid drag, thereby improving gas-liquid contact and mass transfer while also enhancing gas feed utilization. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings and deficiencies of the prior art by providing a gas-feeding reaction and separation coupling device and method that enhances countercurrent mass transfer. By controlling the fluid dynamics of the gas-feed distribution within the reactor and combining this with gas-liquid mass transfer and reaction kinetics, the present invention significantly improves reactor efficiency.

[0005] By thoroughly studying the hydrodynamic distribution behavior of gas within the reactor, the present invention extends the hydraulic retention time of the gas, fully utilizing fluid drag to achieve more complete contact between the gas and pollutants in the water, and enhancing gas-liquid mass transfer while aligning with the efficiency of the reaction process. Separation zones embedded within the reactor periphery are used for gas-liquid-solid phase separation. This invention is suitable for the design of advanced oxidation and biological treatment reactors for wastewater using catalyst-doped ozonation reactions and biologically activated sludge (anaerobic, aerobic, and hydrolysis).

[0006] The present invention is achieved through the following technical solutions:

[0007] A gas-feeding reaction and separation coupling device for enhancing countercurrent mass transfer, comprising:

[0008] Reactor outer cylinder 6;

[0009] A flow guiding inner cylinder 5 is placed in the reactor outer cylinder 6;

[0010] The internal channel of the flow guiding inner tube 5 serves as the fluid rising area 1;

[0011] The channel between the outer wall of the flow guide inner tube 5 and the inner wall of the reactor outer tube 6 serves as the fluid descending zone 2;

[0012] The space between the upper end area of ​​the flow guide inner tube 5 and the top of the reactor outer tube 6 serves as the water separation zone 3;

[0013] The space between the lower end area of ​​the flow guide inner tube 5 and the bottom of the reactor outer tube 6 serves as the bottom gap area 4 .

[0014] A funnel-shaped baffle 13 is provided on the top of the flow guide inner tube 5;

[0015] The effluent separation zone 3 is mainly composed of a three-phase separation device 32 and an effluent weir trough 34;

[0016] The three-phase separation device 32 and the water outlet weir 34 are installed on the inner wall of the reactor outer tube 6;

[0017] The space between the three-phase separation device 32 and the outlet weir 34 forms a sedimentation separation zone 31;

[0018] The bottom pipe opening of the three-phase separation device 32 is connected to the sludge return pipe 33 through a funnel-shaped cover; the pipe opening of the sludge return pipe 33 extends into the fluid descending area 2;

[0019] The fluid descending area 2 is also built with a water inlet pipe 21 and a micron bubble inlet pipe 23;

[0020] The water inlet pipe 21 has a water inlet 22;

[0021] The micron bubble inlet pipe 23 has a micron aeration head 24;

[0022] The positions of the sludge return pipe 33, the micron aeration head 24 and the water inlet 22 below the liquid surface are successively raised;

[0023] An air distribution pipe 12 and a rectifying baffle 42 located above the air distribution pipe 12 are placed in the bottom gap area 12. Large bubbles formed by the air distribution pipe 12 are supplied by an external aeration device connected to the air inlet pipe 11.

[0024] In the channel of the fluid descending area 2, there are multiple large bubble collecting hoods 25 distributed;

[0025] The large bubbles collected by the large bubble collecting hood 25 are collected in the gas outlet main pipe through the pipeline and then enter the fluid rising area 1.

[0026] The positions of the sludge return pipe 33 , the micron aeration head 24 and the water inlet 22 below the liquid surface are successively raised. Specifically, the position of the sludge return pipe 33 below the liquid surface is lower than the position of the micron aeration head 24 below the liquid surface; the position of the micron aeration head 24 below the liquid surface is lower than the position of the water inlet 22 below the liquid surface.

[0027] The internal space of the three-phase separation device 32 constitutes a sedimentation separation zone 31. After the gas-liquid-solid three-phase separation is performed in the sedimentation separation zone 31, the liquid overflows into the outlet weir trough 34 through the holes 35 opened on the side wall of the outlet weir trough 34.

[0028] The three-phase separation device 32 is composed of three vertical pipes. The gas-liquid-solid three-phase mixture enters from the short horizontal pipe outside the sedimentation separation zone 31, flows into the short pipe perpendicular to the horizontal pipe, and then into the vertical pipe. The water and mud flow downward due to gravity. The sludge return pipe 33 returns the sludge to the fluid descending zone 2, and the gas is discharged from the upper part of the vertical pipe.

[0029] The inclination angle of the horizontal pipe in the middle of the three-phase separation pipe to the horizontal plane is 0°-45°;

[0030] The ratio of the fluid rising area 1 to the fluid descending area 2 is 0.4-0.6.

[0031] A mud discharge pipe 41 is installed at the bottom of the bottom gap area 4.

[0032] A feed hole 8 is also provided on the upper portion of the reactor outer cylinder 6 .

[0033] The rectifying baffle 42 causes the fluid to collide rigidly with it during high-speed backflow, changing its direction of motion and reducing energy dissipation caused by the vectorial convergence of multiple fluids. This allows the fluid in the bottom area to exhibit vectorial separation, achieving orderly gas flow and improving the efficiency of the reactor's gas utilization. The bottom gap collects sludge generated throughout the reactor and is placed in an underwater flow propeller for selective discharge through a sludge discharge pipe.

[0034] The gas material release position is 1.0-1.5m underwater in the liquid flow descending area, using a micron-pore aeration head or a mixed fluid of high-pressure dissolved air.

[0035] The middle part of the funnel-shaped deflection baffle 13 is a concave funnel, and the funnel is assembled from four inclined flat plates. The inclination angle between the funnel-shaped baffle and the horizontal plane is 10°-60°.

[0036] The large bubble collection hood 25 is an inverted triangle structure, with a large bubble collection pipe connected to the protrusion, which is used to transfer large bubbles to the fluid rising area. A horizontal plate is placed under the inclined plate to guide the liquid flow and prevent bubbles from overflowing from both sides of the inclined plate and affecting the stirring of the water flow.

[0037] The method for operating the gas-feeding reaction and separation coupling device for enhancing countercurrent mass transfer of the present invention comprises the following steps:

[0038] Large bubbles enter the reactor through the air inlet pipe 11 and the air distribution pipe 12. In the middle of the reactor, they merge with the large bubbles formed by the micron bubbles collected from the fluid descending zone 2 to provide upward stirring power. At the top of the reactor, they are diverted by the funnel-shaped baffle 13, and most of the wastewater returns to the fluid descending zone 2 at high speed, achieving a high-multiple circulation flow.

[0039] In the fluid descending zone 2, wastewater flows evenly through the water inlet 22 via the water inlet pipe 21. It then flows downward due to gravity. To accelerate the chemical reaction rate, 0.5-1.0 m below the water inlet 22, it undergoes countercurrent contact and reaction with a mixed fluid of high-pressure dissolved air, which enters through the micron bubble inlet pipe 23 and is added by the micron aeration head 24. The micron gas material that does not participate in the reaction is pressed downward and diffused by the drag force of the high-speed flowing wastewater. As the pressure increases during the descent process, some micron bubbles coalesce into large bubbles and float upward.

[0040] In order not to affect the fluid mechanics behavior during the descent process, a large bubble collection hood 25 is set in the fluid descent zone 2 to collect large bubbles that overflow from the bottom aeration and enter the fluid descent zone 2, as well as large bubbles generated by coalescence, to prevent large bubbles from moving upward and carrying sludge, causing agitation changes in the water flow and affecting the fluidization process. During the agitation of the wastewater, the opposite movement of the water channel and the gas channel increases the frequency of gas-liquid contact and prolongs the reaction time of the gas and material.

[0041] The gas-liquid-solid three-phase mixture enters the horizontal pipe in the middle of the three-phase separation tube, flows into the short pipe perpendicular to the horizontal pipe, and then enters the vertical pipe. The water and mud flow downward due to gravity. Under the action of fluid drag, the sludge is returned to the fluid descending zone 2 by the sludge return pipe 33 at the bottom of the sedimentation separation zone 31. The gas is discharged from the exhaust hole 7. After the water body circulates back, it enters the outlet weir 34 and is discharged through the outlet pipe 36.

[0042] In the bottom gap area 4, wastewater from the fluid descending area 2 that is flowing back at high speeds is collected. The wastewater flows are similar in flow rate and speed, and collisions may cause huge energy dissipation. In addition, the colliding fluids will form a local circulation at the bottom of the reactor, affecting the uniformity of air and water distribution. Therefore, a type of rectifying baffle 42 is set in the bottom gap area 4 to cause the fluid to rigidly collide with the rectifying baffle 42 during the high-speed reflux process, changing the direction of fluid movement, reducing turbulent kinetic energy, and avoiding energy dissipation caused by the convergence of multiple fluid vectors; the bottom gap area 4 collects the sludge / catalyst / adsorbent settled at the bottom of the reactor and places it in an underwater flow propeller, which can be selectively discharged through the sludge discharge pipe 41;

[0043] Excess gas is discharged through the exhaust hole 7; catalyst and adsorbent can be added through the feed hole 8.

[0044] Principle of the invention:

[0045] The gas enters the reactor from the top through a micron bubble inlet pipe and enters the micron aeration head located in the fluid descending zone. There, it is dispersed into micron bubbles. The drag of the fluid forces the micron bubbles downward, causing them to diffuse. This results in full contact between the gas and liquid phases, and the gas phase dissolves and distributes into the liquid phase. As the micron bubbles descend, some dissolve at an increasing rate as pressure increases. However, due to the Ostwald ripening mechanism, the smaller micron bubbles experience greater pressure within them, creating a pressure difference with the surrounding larger micron bubbles. This pressure difference causes the gas to diffuse from areas of higher pressure to areas of lower pressure, resulting in the growth of larger micron bubbles and the gradual disappearance of smaller ones. Simultaneously, the buoyancy of the larger micron bubbles increases. At a certain point, the drag of the fluid and the buoyancy of the bubbles reach equilibrium, and the micron bubbles move at a constant speed within the reactor, extending their contact time with the wastewater.

[0046] Microbubbles are generated in the descending zone of the fluid. Although they tend to rise within the wastewater, they descend with the wastewater due to fluid drag. According to the Young-Laplace equation and Henry's law, for bubbles with a spherical interface, rising pressure causes their volume to continuously compress. This, coupled with an increase in specific surface area, increases the gas dissolution rate, causing the bubbles to shrink at an increasingly rapid rate, ultimately dissolving into the water. Simultaneously, the presence of the gas-liquid interface in the wastewater subjects the bubbles to the surface tension of the water, which compresses the gas within the bubbles, allowing more of the gas within the bubbles to dissolve into the water through the bubble interface. Therefore, the pressurization characteristics of microbubbles during the gas-liquid countercurrent contact process enhance the gas-liquid interface mass transfer efficiency. This characteristic allows the microbubbles to continue the gas mass transfer process and maintain high efficiency even when the gas content in the water reaches supersaturation.

[0047] Compared with the prior art, the present invention has the following advantages and effects:

[0048] 1. Gas materials are added by quality and region to achieve more efficient utilization. In this invention, gas materials are added from the upper part of the fluid descending zone through a micron aeration head, fully contacting the wastewater in the upstream and downstream countercurrents to increase the frequency of gas-liquid contact. The micron bubbles have a huge specific surface area, which increases the gas-liquid contact area, enhances the ozone mass transfer efficiency, and improves the wastewater treatment efficiency. Air is added from the bottom of the reactor in the form of large bubbles, providing the power for agitation of the fluidized bed, which is used to fully stir and boil the wastewater, sludge and other fluids.

[0049] 2. Enhance interphase mass transfer and improve gas material utilization. The gas-liquid countercurrent contact gas material feeding reactor uses a small amount of large bubble air to achieve the circulation and diversion of the fluid in the fluidized bed, introducing micron bubbles into the circulating fluid descending zone. The balance between the drag force of the downward-flowing liquid with different flow rates and the upward buoyancy of micron bubble particles with different average diameters is utilized, and the efficient utilization of micron bubbles is achieved by regulating the bubble residence time. The fluid flow principle of the internal circulating fluidized bed is used to achieve countercurrent contact of micron bubbles with the liquid phase, strengthening the interphase mass transfer process of micron bubbles and improving dissolution efficiency.

[0050] 3. Change the hydrodynamic behavior of the front-end gas in the reactor, making the gas and pollutants react more quickly and thoroughly. Injecting wastewater into the fluid descending zone creates a concentration gradient, which is inversely distributed with the micron bubble flow field. Relying on the internal circulation diversion effect, while controlling the hydrodynamic behavior of the micron bubbles, it achieves the advantageous kinetic decomposition of pollutants in the wastewater.

[0051] 4. Built-in three-phase separation zone coupled reaction zone and sedimentation separation zone. Placing the sedimentation separation zone inside the reactor enables in-situ separation of sludge, reduces the design of sedimentation tanks in traditional processes, occupies a small area, and has low construction costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a diagram of the internal structure of the gas material feeding reaction and separation coupling device for enhanced countercurrent mass transfer of the present invention (Examples 1, 2, and 3).

[0053] Figure 2 A top view of a three-phase separation device in the separation zone of the gas material feeding reaction and separation coupling device for enhanced countercurrent mass transfer according to the present invention (Examples 1 and 2).

[0054] Figure 3 A top view of the micron bubble inlet pipe of the gas material feeding reaction and separation coupling device for enhanced countercurrent mass transfer of the present invention (Examples 1 and 2).

[0055] Figure 4 A top view of the water inlet pipe of the gas material feeding reaction and separation coupling device for enhanced countercurrent mass transfer of the present invention (Examples 1 and 2).

[0056] Figure 5 A bottom view of the large bubble inlet pipe of the gas material feeding reaction and separation coupling device for enhancing countercurrent mass transfer of the present invention (Examples 1 and 2).

[0057] Figure 6 Three views of the funnel-shaped guide baffle of the gas material feeding reaction and separation coupling device for enhancing countercurrent mass transfer of the present invention (Examples 1 and 2).

[0058] Figure 7 Three views of the large bubble collection hood of the gas material feeding reaction and separation coupling device for enhancing countercurrent mass transfer of the present invention (Examples 1 and 2).

[0059] Figure 8 Three views of the (cross) shaped rectifying baffle of the gas material feeding reaction and separation coupling device for enhancing countercurrent mass transfer of the present invention (Examples 1 and 2).

[0060] Figure 9 Schematic diagram of a single-sided water outlet weir of the gas-feeding reaction and separation coupling device for enhanced countercurrent mass transfer of the present invention (Examples 1 and 2).

[0061] Figure 10 The concentration of ozone dissolved in micron bubbles and large bubbles and the volume dissolved oxygen coefficient of ozone in the present invention (Example 1).

[0062] Figure 11 A three-phase separation device in the separation zone, a micron bubble air inlet pipe, a top view of the water inlet pipe, and a bottom view of the large bubble air inlet pipe of the gas material feeding reaction and separation coupling device for enhanced countercurrent mass transfer of the present invention (Example 3).

[0063] Figure 12 Three views of the funnel-shaped baffle, large bubble collection hood, and straightening baffle of the gas material feeding reaction and separation coupling device for enhancing countercurrent mass transfer of the present invention (Example 3).

[0064] Figure 13 Schematic diagram of the outlet weir of the gas material feeding reaction and separation coupling device for enhanced countercurrent mass transfer of the present invention (Example 3). DETAILED DESCRIPTION

[0065] The present invention is described in further detail below with reference to specific embodiments.

[0066] Example 1:

[0067] A gas-feeding reaction and separation coupling device for enhancing countercurrent mass transfer, comprising:

[0068] Reactor outer cylinder 6;

[0069] A flow guiding inner cylinder 5 is placed in the reactor outer cylinder 6;

[0070] The internal channel of the flow guiding inner tube 5 serves as the fluid rising area 1;

[0071] The channel between the outer wall of the flow guide inner tube 5 and the inner wall of the reactor outer tube 6 serves as the fluid descending zone 2;

[0072] The space between the upper end area of ​​the flow guide inner tube 5 and the top of the reactor outer tube 6 serves as the water separation zone 3;

[0073] The space between the lower end area of ​​the flow guide inner tube 5 and the bottom of the reactor outer tube 6 serves as the bottom gap area 4 .

[0074] A funnel-shaped baffle 13 is provided on the top of the flow guide inner tube 5;

[0075] The effluent separation zone 3 is mainly composed of a three-phase separation device 32 and an effluent weir trough 34 ; the three-phase separation device 32 and the effluent weir trough 34 can be designed as an integrated whole.

[0076] The three-phase separation device 32 and the water outlet weir 34 are installed on the inner wall of the reactor outer tube 6;

[0077] The space between the three-phase separation device 32 and the outlet weir 34 forms a sedimentation separation zone 31;

[0078] The bottom pipe opening of the three-phase separation device 32 is connected to the sludge return pipe 33 through a funnel-shaped cover; the pipe opening of the sludge return pipe 33 extends into the fluid descending area 2;

[0079] The fluid descending area 2 is also built with a water inlet pipe 21 and a micron bubble inlet pipe 23;

[0080] The water inlet pipe 21 has a water inlet 22;

[0081] The micron bubble inlet pipe 23 has a micron aeration head 24;

[0082] The positions of the sludge return pipe 33, the micron aeration head 24 and the water inlet 22 below the liquid surface are successively raised;

[0083] An air distribution pipe 12 and a rectifying baffle 42 located above the air distribution pipe 12 are placed in the bottom gap area 12. Large bubbles formed by the air distribution pipe 12 are supplied by an external aeration device connected to the air inlet pipe 11.

[0084] In the channel of the fluid descending area 2, there are multiple large bubble collecting hoods 25 distributed;

[0085] The large bubbles collected by the large bubble collecting air hood 25 are collected through the pipeline to the air outlet main pipe and then enter the fluid rising zone 1. The large bubble collecting air hood 25 is used to prevent the large bubbles from moving upward (backflow) due to aggregation and formation.

[0086] The positions of the sludge return pipe 33 , the micron aeration head 24 and the water inlet 22 below the liquid surface are successively raised. Specifically, the position of the sludge return pipe 33 below the liquid surface is lower than the position of the micron aeration head 24 below the liquid surface; the position of the micron aeration head 24 below the liquid surface is lower than the position of the water inlet 22 below the liquid surface.

[0087] The internal space of the three-phase separation device 32 constitutes a sedimentation separation zone 31. After the gas-liquid-solid three-phase separation is performed in the sedimentation separation zone 31, the liquid overflows into the outlet weir trough 34 through the holes 35 opened on the side wall of the outlet weir trough 34.

[0088] The three-phase separation device 32 is composed of three vertical pipes. The gas-liquid-solid three-phase mixture enters from the short horizontal pipe outside the sedimentation separation zone 31, flows into the short pipe perpendicular to the horizontal pipe, and then into the vertical pipe. The water and mud flow downward due to gravity. The sludge return pipe 33 returns the sludge to the fluid descending zone 2, and the gas is discharged from the upper part of the vertical pipe.

[0089] The inclination angle of the horizontal pipe in the middle of the three-phase separation pipe to the horizontal plane is 0°-45°;

[0090] The ratio of the fluid rising area 1 to the fluid descending area 2 is 0.4-0.6.

[0091] A mud discharge pipe 41 is installed at the bottom of the bottom gap area 4.

[0092] A feed hole 8 is also provided on the upper portion of the reactor outer cylinder 6 .

[0093] The method for operating the gas-feeding reaction and separation coupling device for enhancing countercurrent mass transfer of the present invention comprises the following steps:

[0094] Large bubbles enter the reactor through the air inlet pipe 11 and the air distribution pipe 12. In the middle of the reactor, they merge with the large bubbles formed by the micron bubbles collected from the fluid descending zone 2 to provide upward stirring power. At the top of the reactor, they are diverted by the funnel-shaped baffle 13, and most of the wastewater returns to the fluid descending zone 2 at high speed, achieving a high-multiple circulation flow.

[0095] In the fluid descending zone 2, wastewater flows evenly through the water inlet 22 via the water inlet pipe 21. It then flows downward due to gravity. To accelerate the chemical reaction rate, 0.5-1.0 m below the water inlet 22, it undergoes countercurrent contact and reaction with a mixed fluid of high-pressure dissolved air, which enters through the micron bubble inlet pipe 23 and is added by the micron aeration head 24. The micron gas material that does not participate in the reaction is pressed downward and diffused by the drag force of the high-speed flowing wastewater. As the pressure increases during the descent process, some micron bubbles coalesce into large bubbles and float upward.

[0096] In order not to affect the fluid mechanics behavior during the descent process, a large bubble collection hood 25 is set in the fluid descent zone 2 to collect large bubbles that overflow from the bottom aeration and enter the fluid descent zone 2, as well as large bubbles generated by coalescence, to prevent large bubbles from moving upward and carrying sludge, causing agitation changes in the water flow and affecting the fluidization process. During the agitation of the wastewater, the opposite movement of the water channel and the gas channel increases the frequency of gas-liquid contact and prolongs the reaction time of the gas and material.

[0097] The gas-liquid-solid three-phase mixture enters the horizontal pipe in the middle of the three-phase separation tube, flows into the short pipe perpendicular to the horizontal pipe, and then enters the vertical pipe. The water and mud flow downward due to gravity. Under the action of fluid drag, the sludge is returned to the fluid descending zone 2 by the sludge return pipe 33 at the bottom of the sedimentation separation zone 31. The gas is discharged from the exhaust hole 7. After the water body circulates back, it enters the outlet weir 34 and is discharged through the outlet pipe 36.

[0098] In the bottom gap region 4, wastewater from the fluid descending region 2, which is experiencing high-speed reflux, converges here. Since the wastewater flows at similar speeds and flow rates, a collision can result in significant energy dissipation. Furthermore, the colliding fluids can form a localized circulation at the bottom of the reactor, affecting the uniformity of gas and water distribution. Therefore, a (cross-shaped) rectifier baffle 42 is provided in the bottom gap region 4 to cause the fluid to rigidly collide with the rectifier baffle 42 during high-speed reflux, changing the direction of fluid motion, reducing turbulent kinetic energy, and avoiding energy dissipation caused by the convergence of multiple fluid vectors, as shown in Table 1. The addition of the (cross-shaped) rectifier baffle 42 causes the fluid in the bottom region to exhibit vector separation, achieving orderly gas and material flow and improving the utilization efficiency of the reactor gas and material.

[0099] The bottom gap area 4 collects the sludge / catalyst / adsorbent settled at the bottom of the reactor and places it into an underwater flow propeller, which can be selectively discharged through the sludge discharge pipe 41;

[0100] Excess gas is discharged through the exhaust hole 7; catalyst and adsorbent can be added through the feed hole 8.

[0101] Table 1 Effect of cross-shaped rectifying baffle on average turbulent kinetic energy

[0102]

[0103] In the present invention, ozone bubbles are selected as the gas material and added at the micron aerator (head). In order to verify the ability of micron bubbles to improve mass transfer, two types of large bubbles with a particle size of 1.00 mm and micron bubbles with a particle size of 5.00 μm are used in the experiment. When the ozone addition flow rate is 1.00 L / min, the ozone concentration is 38.10 mg / L, and the ozone saturation concentration in the aqueous solution is 332.65 μM, large bubbles and micro bubbles are used for aeration respectively. The dissolved ozone concentration in the aqueous solution is detected at 0, 1, 3, 5 and 10 minutes. The volume dissolved oxygen coefficient (KLa) of ozone is calculated according to formula (1) and formula (2), as shown in FIG. Figure 10 shown.

[0104] dC / dt=K L a×(C*-C t ) (1)

[0105] ln(C*-C t )=-K L a×t+C (2)

[0106] Among them, K L a is the volume dissolved oxygen coefficient of ozone (min -1 ), C* is the saturated dissolved ozone concentration of the solution (μM), C t is the dissolved ozone concentration in the solution at time t (μM).

[0107] from Figure 10 As can be seen in a, the dissolved ozone concentration in microbubble aeration is not much different from that in large bubble aeration within 1 minute. As the aeration time increases, the dissolved ozone concentration in the solution shows a difference. Figure 10 b. The volume dissolved oxygen coefficient of ozone is 0.149min when aerated with large bubbles. -1 , 0.277min when using micron bubble aeration -1 .After using micron aeration, K L a is significantly improved, which is 1.86 times that of large bubble aeration. It can be seen that microbubble aeration enhances ozone mass transfer and can further improve the mineralization degree when used in wastewater treatment.

[0108] The rising velocity of the bubble is roughly described by the theoretical value according to Stokes' law (Equation (3)):

[0109] u = 1 / 18 × gd 2 / ν (3)

[0110] Where u is the rising velocity of the bubble (m / s), g is the acceleration due to gravity (m / s 2 ), d is the diameter of the bubble (m), ν is the kinematic viscosity of water (1.34×10 -6 m2 / s). Calculations show that the natural rise velocity of a 1.00mm large bubble in static water at normal temperature and pressure is 406mm / s, while the natural rise velocity of a 5.00μm micron bubble under the same conditions is 0.0102mm / s. This indicates that microbubbles rise slowly and reside for a long time, increasing the frequency of gas-liquid contact. The average flow rate in a fluidized bed reactor is 0.15-0.50m / s. When the controlled flow rate is greater than the rise velocity of large bubbles (particle size 1.00mm), the large bubbles tend to be pushed downward. However, if the liquid flow rate is less than 0.40m / s, the large bubbles migrate upward and diffuse until they reach the liquid surface, bursting and disappearing. The rise velocity of micron bubbles is much lower than the liquid flow rate. Therefore, under the drag force of the circulating liquid in the fluidized bed, the micron bubbles are forced downward and directed, resulting in full contact between the gas and liquid phases, and the gas phase substances dissolve and distribute into the liquid phase. As the micron bubbles descend, some of them dissolve at an accelerated rate as the pressure increases. The remaining micron bubbles, according to the Ostwald ripening mechanism, have a higher pressure inside the smaller micron bubbles and a pressure difference between them and the larger micron bubbles around them. The pressure difference between the bubbles causes the gas to diffuse from areas with higher pressure to areas with lower pressure, resulting in the larger micron bubbles growing larger and the smaller micron bubbles gradually disappearing.

[0111] Microbubbles are generated in the descending zone of the fluid. Although they tend to rise within the wastewater, they descend with the wastewater due to fluid drag. According to the Young-Laplace equation and Henry's law, for bubbles with a spherical interface, rising pressure causes their volume to continuously compress. This, coupled with an increase in specific surface area, increases the gas dissolution rate, causing the bubbles to shrink at an increasingly rapid rate, ultimately dissolving into the water. Simultaneously, the presence of the gas-liquid interface in the wastewater subjects the bubbles to the surface tension of the water, which compresses the gas within the bubbles, allowing more of the gas within the bubbles to dissolve into the water through the bubble interface. Therefore, the pressurization characteristics of microbubbles during the gas-liquid countercurrent contact process enhance the gas-liquid interface mass transfer efficiency. This characteristic allows the microbubbles to continue the gas mass transfer process and maintain high efficiency even when the gas content in the water reaches supersaturation.

[0112] Implementation Case 2:

[0113] This implementation case is aimed at the catalytic ozonation unit with catalyst addition in the coking wastewater treatment process; the gas material addition reaction and separation coupling device with enhanced countercurrent mass flow. The catalytic ozone reactor has the following dimensions: L×B×H=1.6m×1.6m×6.7m, effective water depth: 6.4m, effective volume: 16.384m 3 , material: steel structure, specifically including the following steps.

[0114] In the fluid ascending zone, large air bubbles enter the reactor through the air inlet pipe and the air distribution pipe. In the middle of the reactor, they provide upward stirring power together with the large bubbles formed by the merger of ozone micron bubbles collected from the fluid descending zone. At the upper part of the reactor, they are guided by the funnel-shaped guide baffle, and most of the wastewater returns to the fluid descending zone at high speed, realizing high-multiple circulation flow.

[0115] In the fluid descending zone, the biological effluent of coking wastewater flows evenly into the reactor through the water inlet via the water inlet pipe. It flows downward from the reactor descending zone due to gravity. In order to accelerate the chemical reaction rate, it contacts and reacts with the ozone micron bubbles in a countercurrent manner 0.5-1.0m below the water inlet.

[0116] The unreacted ozone micron gas is pressed downward and diffused by the drag of the high-speed flowing wastewater. As the pressure increases during the descent, some ozone micron bubbles coalesce into larger bubbles and float upward. To ensure that the fluid dynamics during the descent are not affected, a large bubble collection hood is installed in the fluid descent zone. This hood collects large air bubbles that overflow from the bottom aeration and enter the descent zone, as well as large ozone bubbles generated by coalescence. This prevents these large bubbles from moving upward, dragging up sludge and causing changes in the water flow, which could affect the fluidization process.

[0117] During the agitation of the biological effluent from coking wastewater, the opposing motion of the water and gas pathways increases the frequency of gas-liquid contact and prolongs the reaction time of the gas and material. The effluent separation zone is located within the reactor, surrounding the outer cylinder wall, and contains a three-phase separation and sedimentation zone. Within this zone, the three-phase separation device consists of three perpendicular tubes. The gas-liquid-solid three-phase mixture enters through a short horizontal tube outside the zone, flows into a short tube perpendicular to the horizontal tube, and then into a vertical tube. Water and sludge flow downward due to gravity. The sludge return pipe at the bottom of the three-phase separation and sedimentation zone, under the influence of fluid drag, returns the sludge to the fluid descending zone, while the gas is discharged from the top. After circulating back, the water passes through the surrounding effluent perforated plates into the effluent weir and is discharged through the effluent pipe.

[0118] In the bottom gap, high-speed wastewater reflows from the surrounding fluid-falling zones converge. These four wastewater streams have similar flow rates and velocities, potentially resulting in significant energy dissipation in the event of a collision. The addition of a cross-shaped rectifying baffle enables vector separation of the fluids in the bottom region, enabling orderly flow of the two gas streams and improving the efficiency of the reactor's gas feed. The bottom gap collects the sludge and ozone catalyst that settles at the bottom of the reactor. These are then placed in an underwater flow propeller and selectively discharged through a sludge discharge pipe. The ozone catalyst, powdered activated carbon, is dosed through a feed port at the top of the reactor.

[0119] The horizontal tube in the middle of the three-phase separation tube has an inclination angle of 10° to the horizontal plane;

[0120] The ratio of the fluid rising area to the fluid falling area is 0.5625:1;

[0121] The height-to-diameter ratio of the reactor (cube) is 4:1;

[0122] The flat plate constituting the baffle has an inclination angle of 45° to the horizontal plane.

[0123] Influent COD = 200-300 mg / L, BOD5 = 12.8-15.4 mg / L, NH4 + -N=0.67-1.31mg / L, TN=22.1-36.6mg / L;

[0124] Process organic loading rate = 1.44 kg COD / m 3 / d; ozone dosage = 239g / h; reactor hydraulic retention time 2h; reactor sludge retention time 2d;

[0125] Reactor COD, BOD5, NH4 + The removal rates of -N and TN were 56.2%, 23.4%, 71.7% and 39.9% respectively.

[0126] Implementation Case 3:

[0127] The main internal structure of this embodiment is the same as that of embodiment 1, and the similarities are not repeated here. The difference is that: Figures 11 to 13 As shown, the length-to-width ratio of the gas-feeding reaction and the separation coupling reactor for enhanced countercurrent mass transfer is different. This embodiment adopts a biological aerobic fluidized degradation method to treat coking wastewater. The reactor design follows the same ratio of the ascending zone to the descending zone as in Example 1, and changes the length-to-width ratio to achieve biological aerobic degradation.

[0128] This embodiment strengthens the countercurrent mass flow of gas-feeding reaction and separation coupling device. The biological aerobic fluidized bed has the following dimensions: L×B×H=1.6m×3.1m×6.7m, effective water depth: 6.4m, effective volume: 31.744m 3 , material: steel concrete structure, specifically including the following steps.

[0129] In the fluid rising zone, large air bubbles enter the reactor through the large bubble inlet pipe and the air distribution pipe. In the middle of the reactor, they provide upward stirring power together with the large bubbles formed by the merger of oxygen micron bubbles collected from the descending zone. At the upper part of the reactor, they are guided by the funnel-shaped guide baffle, and most of the wastewater returns to the fluid descending zone at high speed, realizing high-multiple circulation flow.

[0130] In the fluid descending zone, coking wastewater flows evenly into the reactor through the inlet pipe and the water inlet. Due to gravity, it flows downward from the reactor descending zone. To accelerate the chemical reaction rate, it comes into countercurrent contact and reaction with the oxygen micron bubbles 0.5-1.0m below the water inlet. The unreacted oxygen micron gas is pressed downward and diffused by the drag of the high-speed flowing wastewater. As the pressure increases during the descent, some of the oxygen micron bubbles coalesce into larger bubbles and float upward.

[0131] To ensure that the fluid's mechanical behavior during the descent process is not affected, a large bubble collection hood is installed in the descent zone. This hood collects large air bubbles that overflow from the bottom aeration system and oxygen bubbles that coalesce to prevent them from moving upward, dragging sludge and causing agitation in the water flow, which could affect the fluidization process. During the agitation of the coking wastewater, the opposing motion of the water and gas paths increases the frequency of gas-liquid contact and prolongs the reaction time between the gas and the material.

[0132] The effluent separation zone, located within the reactor, surrounds the outer cylinder wall and contains a three-phase separation and settling zone. Within this zone, the three-phase separation device consists of three perpendicular tubes. The gas-liquid-solid three-phase mixture enters through a short horizontal tube outside the zone, flows into a short tube perpendicular to the horizontal tube, and then into a vertical tube. Water and sludge flow downward due to gravity. The sludge return pipe at the bottom of the three-phase separation and settling zone, under the influence of fluid drag, returns the sludge to the fluid descending zone, while the gas is discharged from the top. After circulating back through the surrounding perforated plates, the water enters the effluent weir and is discharged through the outlet pipe. In the bottom gap, high-speed wastewater returning from the surrounding fluid descending zones converges. The four wastewater streams have similar flow rates and velocities, and collisions can result in significant energy dissipation. The addition of a cross-shaped flow straightening baffle enables vector separation of the fluid in the bottom zone, ensuring orderly flow of the two gas streams and improving the reactor's gas and feed utilization efficiency. The bottom gap collects the sludge and coagulant settled at the bottom of the reactor and places them into an underwater flow propeller, which can be selectively discharged through the sludge discharge pipe. Coagulant and other chemicals are added through the feed port at the top of the reactor in a dosing manner.

[0133] The horizontal tube in the middle of the three-phase separation tube has an inclination angle of 30° to the horizontal plane;

[0134] The ratio of rising area to falling area is 0.5625:1;

[0135] The height-to-diameter ratio of the cubic reactor is 4:1;

[0136] The flat plate constituting the baffle has an inclination angle of 45° to the horizontal plane.

[0137] Influent COD = 352-414 mg / L, BOD5 = 68.4-128.1 mg / L, NH4 +-N=6.61-9.73mg / L, TN=22.1-37.8mg / L;

[0138] Process organic loading rate = 0.50kg COD / m 3 / d; dissolved oxygen DO = 3.46 mg / L; reactor hydraulic retention time 44h; reactor sludge retention time 18d;

[0139] Reactor COD, BOD5, NH4 + The removal rates of -N and TN were 41.8%, 85.6%, 86.5% and 3.17% respectively.

[0140] As described above, the present invention can be implemented better.

[0141] The implementation methods of the present invention are not limited to the above-mentioned embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A gas-feeding reaction and separation coupling device for enhancing countercurrent mass transfer, characterized in that include: Reactor outer cylinder (6); A flow guide inner cylinder (5) placed inside a reactor outer cylinder (6); The internal channel of the flow guiding inner cylinder (5) serves as the fluid rising area (1); The channel between the outer wall of the flow guide inner tube (5) and the inner wall of the reactor outer tube (6) serves as the fluid descending zone (2); The space between the upper end area of ​​the flow guide inner cylinder (5) and the top of the reactor outer cylinder (6) serves as the water separation zone (3); The space between the lower end area of ​​the guide inner tube (5) and the bottom of the reactor outer tube (6) serves as the bottom gap area (4); A funnel-shaped deflection baffle (13) is provided on the top of the flow-guiding inner cylinder (5); The effluent separation zone (3) is mainly composed of a three-phase separation device (32) and an effluent weir (34); The three-phase separation device (32) and the water outlet weir (34) are installed on the inner wall of the reactor outer cylinder (6); The space between the three-phase separation device (32) and the outlet weir (34) forms a sedimentation separation zone (31); The bottom pipe opening of the three-phase separation device (32) is connected to the sludge return pipe (33) through a funnel-shaped cover; the pipe opening of the sludge return pipe (33) extends into the fluid descending zone (2); The fluid descending area (2) is also provided with a water inlet pipe (21) and a micron bubble inlet pipe (23); The water inlet pipe (21) has a water inlet (22); The micron bubble inlet pipe (23) has a micron aeration head (24); The positions of the sludge return pipe (33), the micron aeration head (24) and the water inlet (22) below the liquid surface are successively raised; An air distribution pipe (12) and a rectifying baffle (42) located above the air distribution pipe (12) are placed in the bottom gap area (4). Large bubbles formed by the air distribution pipe (12) are supplied by an air inlet pipe (11) connected to an external aeration device. In the channel of the fluid descending area (2), a plurality of large bubble collecting hoods (25) are distributed; The large bubbles collected by the large bubble collecting hood (25) are collected in the gas outlet main pipe through the pipeline and then enter the fluid rising zone (1).

2. The gas-material feeding reaction and separation coupling device for enhancing countercurrent mass transfer according to claim 1, characterized in that: The positions of the pipe opening of the sludge return pipe (33), the micron aeration head (24) and the water inlet (22) below the liquid surface are successively raised. The position of the pipe opening of the sludge return pipe (33) below the liquid surface is lower than the position of the micron aeration head (24) below the liquid surface; and the position of the micron aeration head (24) below the liquid surface is lower than the position of the water inlet (22) below the liquid surface.

3. The gas-material feeding reaction and separation coupling device for enhancing countercurrent mass transfer according to claim 1, characterized in that: The internal space of the three-phase separation device (32) constitutes a sedimentation separation zone (31). After the gas-liquid-solid three-phase separation is performed in the sedimentation separation zone (31), the gas overflows into the outlet weir trough (34) through the holes (35) opened on the side wall of the outlet weir trough (34).

4. The gas-material feeding reaction and separation coupling device for enhancing countercurrent mass transfer according to claim 3, characterized in that: The three-phase separation device (32) is composed of three vertical pipes. The gas-liquid-solid three-phase mixture enters from the short pipe placed horizontally outside the sedimentation separation zone (31), flows into the short pipe perpendicular to the horizontal pipe, and then into the vertical pipe. Water and mud flow downward due to gravity. The sludge return pipe (33) returns the sludge to the fluid descending zone (2), and the gas is discharged from the upper part of the vertical pipe.

5. The gas-material feeding reaction and separation coupling device for enhancing countercurrent mass transfer according to claim 4, characterized in that: The inclination angle of the horizontal pipe in the middle of the three-phase separation pipe to the horizontal plane is 0°-45°; The ratio of the fluid ascending area (1) to the fluid descending area (2) is 0.4-0.

6.

6. The gas-material addition reaction and separation coupling device for enhanced countercurrent mass transfer according to claim 1, characterized in that: A mud discharge pipe (41) is installed at the bottom of the bottom gap area (4).

7. The gas-material addition reaction and separation coupling device for enhanced countercurrent mass transfer according to claim 1, characterized in that: A feed hole (8) is also provided on the upper portion of the reactor outer cylinder (6).

8. The method for operating the gas-feeding reaction and separation coupling device for enhanced countercurrent mass transfer according to any one of claims 1 to 5, characterized in that The steps include: Large bubbles enter the reactor through the air inlet pipe (11) and the air distribution pipe (12). In the middle of the reactor, they combine with the large bubbles formed by the merging of micron bubbles collected from the fluid descending zone (2) to provide the power for upward stirring. At the upper part of the reactor, they are diverted by the funnel-shaped baffle (13), and most of the wastewater returns to the fluid descending zone (2) at a high speed. In the fluid descending zone (2), wastewater flows uniformly into the fluid descending zone (2) through the water inlet (22) via the water inlet pipe (21), and flows downward due to gravity. In order to accelerate the chemical reaction rate, at 0.5-1.0 m below the water inlet (22), it is countercurrently contacted and reacted with the mixed fluid of high-pressure dissolved air that enters through the micron bubble inlet pipe (23) and is added by the micron aeration head (24); the micron gas material that does not participate in the reaction is pressed down and diffused under the drag force of the high-speed flowing wastewater. During the descending process, as the pressure increases, some micron bubbles gather into large bubbles and float upward; In order not to affect the fluid mechanics behavior during the descent process, a large bubble collection hood (25) is set in the fluid descent zone (2) to collect large bubbles overflowing from the bottom aeration into the fluid descent zone (2) and large bubbles generated by coalescence, so as to prevent the large bubbles from moving upward and carrying sludge to cause agitation changes in the water flow, thereby affecting the fluidization process; during the agitation process of the wastewater, the opposite movement of the water channel and the gas channel increases the frequency of gas-liquid contact and prolongs the reaction time of the gas and material; The gas-liquid-solid three-phase mixture enters from the horizontal pipe in the middle of the three-phase separation pipe, flows into the short pipe perpendicular to the horizontal pipe, and then enters the vertical pipe. The water and mud flow downward due to gravity. The sludge return pipe (33) at the bottom of the sedimentation separation zone (31) returns the sludge to the fluid descending zone (2) under the action of fluid drag, and the gas is discharged from the exhaust hole (7); After circulating back, the water enters the outlet weir (34) and is discharged from the outlet pipe (36); In the bottom gap area (4), wastewater from the fluid descending area (2) with high speed backflow is collected here. A type rectifying baffle (42) is provided in the bottom gap area (4) so ​​that the fluid can rigidly collide with the rectifying baffle (42) during the high speed backflow process, thereby changing the direction of fluid movement, reducing turbulent kinetic energy, and avoiding energy dissipation caused by the convergence of multiple fluid vectors. The bottom gap area (4) collects the sludge / catalyst / adsorbent settled at the bottom of the reactor, places it into an underwater flow propeller, and selectively discharges it through the sludge discharge pipe (41); The exhaust hole (7) discharges excess gas; the catalyst and adsorbent are added through the feed hole (8).

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