CN107563051A - Micro-interface enhanced reactor bubble scale structure imitates regulation-control model modeling method - Google Patents

Abstract

The invention relates to a modeling method of a bubble scale structure-effect regulation model of a micro-interface strengthening reactor, which takes the maximum bubble diameter _dmax and the minimum bubble diameter _dmin of the _{microinterface} strengthening reactor as independent variables, and the bubble Sauter average diameter d32 as a dependent variable The numerical relationship was constructed; and based on the Kolmogorov‑Hinze theory, the relationship between the maximum bubble diameter d _max , the minimum bubble diameter d _min and the reactor parameters of the micro-interface strengthening reactor was constructed. The method of the present invention links the bubble size of the reactor with the structural parameters, operating parameters and physical parameters of the reactor with specific numerical relationships, which has guiding significance for the design of the reactor, and is applicable to various reactors, and is universal Good performance, the bubble scale control model constructed by the modeling method of the present invention can further adjust the structural parameters and operating parameters of the reactor to obtain the maximum target of energy efficiency and material efficiency in the reaction process, or in a given reaction target and energy consumption Under the material consumption, an efficient reactor structure is designed.

Description

Bubble-scale structure-effect control model modeling method for micro-interface strengthening reactor

technical field

The invention belongs to the technical fields of chemical manufacturing, reactors and modeling, and in particular relates to a modeling method for a bubble-scale structure-effect control model of a micro-interface strengthening reactor.

Background technique

Heterogeneous reactions such as oxidation, hydrogenation, and chlorination widely exist in chemical production processes, and their macroscopic reaction rates are generally restricted by mass transfer processes. The mass transfer rate of the gas-liquid reaction is mainly affected by the liquid side (or gas side) mass transfer coefficient and the gas-liquid interfacial area a. Previous studies have shown that a has a greater influence on the volumetric mass transfer coefficient and is easy to control. Therefore, increasing a is considered to be a particularly effective way to improve the reaction efficiency of gas-liquid reaction systems controlled by mass transfer.

Bubble Sauter average diameter d ₃₂ is one of the key parameters to determine the size of a, and they are mainly affected by the interaction force between bubbles and gas-liquid two phases. Bubble coalescence and splitting are the results of the above two forces, respectively, and affect the size of the bubble diameter. Therefore, bubble coalescence and collapse, as the mesoscopic behavior of bubbles, are the deep-seated reasons for determining the size of a. The research on the bubble coalescence and splitting behavior has a long history, and it is generally believed that the energy dissipation rate and d ₃₂ are important influencing factors. In fact, d ₃₂ can affect a and the volumetric mass transfer coefficient, and is the core factor determining the gas-liquid macroscopic reaction rate ^[1] . Studies have shown that when d ₃₂ gradually decreases, the volumetric mass transfer rate increases gradually; especially when d ₃₂ is less than 1mm, the volumetric mass transfer rate increases rapidly with the decrease of d ₃₂ similar to an exponential form. Therefore, reducing d ₃₂ as much as possible can enhance the gas-liquid mass transfer and ultimately increase the macroscopic reaction rate.

Bubble reactors and stirred-bubble reactors are the most traditional and commonly used gas-liquid reactors in industry. For example, in the tower-type bubbling reactor for PX oxidation to TA, the diameter of the bubbles is usually larger than 10 mm, or even a few centimeters, and its mass transfer interface area is very limited. Therefore, the reactor must be made very large to increase the macroscopic reaction rate. At the same time, it must Promote liquid turbulence by increasing air blowing volume, increase gas holdup, and then increase interface area, but this will inevitably reduce the utilization rate of oxygen in the air, increase compressor power and exhaust emissions, resulting in excessive energy consumption and material loss. environmental pollution. From the perspective of turbulence dynamics, the traditionally most widely used stirred-bubble gas-liquid reactors mostly form large eddies that affect the macroscopic movement of bubbles but have little effect on bubble breakup. The bubbles cannot be broken effectively, so the bubbles If the diameter is too large, the mass transfer area is limited, so that the reaction efficiency is low. In order to strengthen gas-liquid mass transfer, tower-type bubbling reactors are generally equipped with internal parts such as gas distribution plates and static mixers to enhance mixing, while stirred tanks need to be equipped with different structures such as stirring paddles or inner cylinders to increase the liquid layer. gas content. However, the diameter of the bubbles in these two reactors is usually 5-20mm, and the provided phase boundary area per unit volume is very limited, generally less than 100m ² /m ³ , so it is impossible to achieve a breakthrough increase in reaction efficiency. Therefore, in industry, the gas holdup and phase boundary area are often increased through high temperature and high pressure and increased gas volume, but this has a significant negative impact on the energy consumption, material consumption and reaction selectivity of the reaction process.

Due to the importance of research and development of micro-crushing technology of bubbles, universities and research institutions in Britain, the United States, Germany, Japan and other countries have begun to pay attention to and develop ultra-fine bubble technology in the past 10 years ^[2-11] , but their research results have the following common defect:

(1) Although a certain amount of micron-sized bubbles can be obtained by mechanical crushing, fluid impact, ultrasonic and other means, the gas-liquid ratio (the ratio of gas volume to liquid volume) is too low, generally lower than 1%, and the upper limit does not exceed 5 %. In addition, the energy consumption and manufacturing cost of the equipment for generating microbubbles are too high.

(2) There are no micro-bubble system characteristics based on the continuous liquid phase and high turbulence at home and abroad. Systematic micro-interface mass transfer enhancement theory, micro-bubble testing and characterization methods, and micro-interface enhanced reactor structure-effect control theory have not been proposed. and related mathematical models.

Based on the above reasons, although sporadic application experiment results have been published, there is no large-scale industrial application report, especially in the field of chemical manufacturing, which is basically still in a blank state.

Chemical production in today's era is based on the overall consideration of innovation, greenness, and environmental protection. Its survival and development depend on substantial innovations in materials and process technologies. Improving the atomic economy of the reaction and separation process is crucial to reducing energy consumption, material consumption, and enhancing competitiveness. Based on this, we proposed a new technology of "micro-interface mass transfer enhanced reaction-fine separation integrated system", trying to start from the most basic research on the characteristics of ultra-fine gas-liquid particles, to solve the problem of micro-interface chemistry in the ultra-fine particle system in a highly turbulent state. Theoretical, technical and application issues involved in the whole process of structure-effect regulation such as fluid flow, mass transfer, reaction and energy conversion in the reactor.

The ultrafine gas-liquid particles involved in the present invention refer to ultrafine bubbles (or ultrafine liquid droplets), which are micron-sized gas-liquid particles with a particle equivalent diameter of 1 μm≤d ₀ <1 mm. In the reaction system, ultrafine gas-liquid particles form ultrafine interfaces (or microinterfaces), and the formation of ultrafine interfaces greatly enhances mass transfer and reaction rate, especially in reaction systems controlled by mass transfer.

It should be emphasized that the classical gas-liquid mixing theory is generally based on the characteristics of gas-liquid particles at the millimeter-centimeter scale, and the most reasonable method at present is the multiscale energy minimization principle (EMMS) ^[12] . Most of the current research work is aimed at the millimeter-scale upbubbles in traditional gas-liquid reactors ^[13,14] , and rarely involves ultrafine particle systems. For the mixing, mass transfer and reaction characteristics of ultrafine particle systems, new calculation models, testing and characterization methods, and structure-activity control models must be established. For this reason, new equipment structures, energy input methods, and conversion models must be studied to form The brand-new computing software and hardware platform suitable for ultrafine particle reaction system provides technical and equipment support for my country's process industry production technology to a new level.

There are generally two types of research on the d ₃₂ algorithm in the prior art:

1. Among them, n _i represents the number of bubbles, and d _i represents the diameter of the bubbles; the disadvantage of this algorithm is that it is necessary to know the diameter and number of all bubbles in the system, which cannot be done at present, and this formula does not include the structure of the reactor Parameters, operating parameters, and physical parameters have no guiding significance for the design of the reactor, and are not a real structure-activity control model;

2. d ₃₂ ＝αd _max , the proportional coefficient α in this formula is estimated by experience, and it can only be used for some specific systems, and the error is relatively large.

The so-called structure-effect regulation mathematical model refers to linking the reaction efficiency (energy efficiency and physical efficiency) of the ultra-fine gas-liquid particle reaction system with the physical and chemical characteristics of the system, micro-interface characteristics, mass transfer characteristics and reactor structure with mathematical methods, so as to realize The goal of maximizing the energy efficiency and material efficiency of the reaction process can be obtained by adjusting the structural parameters and operating parameters, or under the given reaction goals (tasks) and energy and material consumption, an efficient reactor structure can be designed. As for the micro-interface strengthening reactor, the work in this area is still blank in the world.

references

[1]Levenspiel O.Chemical Reaction Engineering[M].Wiley New York etc.,1972.

[2]Xu JH, Li SW, Chen GG, LuoG..Formation of monodisperse microbubbles in microfluidic device[J].AIChE Journal,2006,52(6):2254-2259.

[3]Li P and Tsuge H.Ozone transfer in a new gas-induced contactorwith microbubbles[J].Journal of Chemical Engineering of Japan,2006,39(11):1213-1220.

[4] Muroyama K, Imai K, Oka Y, Hayashi J, Mass transfer properties in abubble column associated with micro-bubble dispersions [J]. Chemical Engineering Science, 201, 100: 464-473.

[5] Maeda Y, Hosokawa S, Baba Y, Tomiyama Akio. Generation mechanism of micro-bubbles in a pressurized dissolution method [J]. Experimental Thermal and Fluid Science, 2015, 60: 201-207.

[6] Hasegawa H, Nagasaka Y, Kataoka H. Electrical potential of microbubble generated by shear flow in pipe with slits. Fluid Dynamics Research, 2008, 40(7-8):554-564.

[7]Weber J and Agblevor F.Microbubble fermentation of Trichodermareesei for cellulase production[J].Process Biochemistry,2005,40(2):669-676.

[8] Rehman F, Medley GJ, Bandulasena H, Zimmerman WB. Fluidic oscillator-mediated microbubble generation to provide cost effective mass transfer and mixing efficiency to the wastewater treatment plants [J]. Environmental research, 2015, 137: 32-39.

[9]Stride E and Edirisinghe M.Novel microbubble preparationtechnologies[J].Soft Matter,2008,4(12):2350.

[10] Druzinec D, Salzig De, Kraume M, Czermak P. Micro-bubble aeration inturbulent stirred bioreactors: Coalescence behavior in Pluronic F68 containing cell culture media [J]. Chemical Engineering Science, 2015, 126: 160-168.

[11] Li Baozhang, Shang Longan, Jiang Xinzhen. Research on Inverted Jet Loop Reactor [J]. Journal of Northwest University (Natural Science Edition). 1989, 04:65-69.

[12]Chen JH, Yang N, Ge W, Li JH.Stability-driven structure evolution:exploring the intrinsic similarity between gas-solid and gas-liquid systems[J].Chinese Journal of Chemical Engineering.2012,20(1) :167-177.

[13]Hinze JO. Fundamentals of the hydrodynamic mechanism of splittingin dispersion processes[J].AIChE Journal.1955,1(3):289-295.

[14]Zhong S, Zou X, Zhang ZB, Tian HZ.A flexible image analysis method for measuring bubble parameters[J].Chemical Engineering Science,2016,141(17):143-153.

Contents of the invention

The object of the present invention is to overcome the defects of the prior art and provide a modeling method for the micro-interface strengthening reactor bubble scale structure-effect control model.

To achieve the above object, the present invention adopts the following technical solutions:

A method for modeling a bubble-scale structure-effect regulation model of a micro-interface strengthening reactor, comprising:

(1) Taking the maximum bubble diameter d _max and the minimum bubble diameter d _min of the micro-interface strengthening reactor as independent variables, and the bubble Sauter average diameter d ₃₂ as the dependent variable, establish the relationship between d _max , d _min and d ₃₂ ; the specific steps are as follows :

Let x, m, and n be the mean and standard deviation of the bubble particle size and the geometric natural logarithm of the bubble particle size in the gas-liquid system of the reactor, respectively, and obtain the probability density function of the bubble particle size x:

The bubble Sauter average diameter d ₃₂ when the bubble particle size satisfies this distribution is:

d ₃₂ ＝exp(m+2.5n ² ) (2)

The bubble size x is log-normally distributed, so the mathematical expectation (arithmetic mean) of lnx is: According to the probability density function of the bubble particle size x, the probability density map of the bubble particle size is drawn, when When , the probability density is the largest; that is, the first derivative here is 0:

Substituting equation (3) into (1) yields equation (4):

From (3), (4) can get:

because:

After substituting equation (1) into (6) and simplifying, we get:

make: Then the above formula simplifies to:

The left end of Equation (8) is the error function, and the difference with the standard error function lies in the difference of the integral limit. Substituting Equation (5) into the upper and lower limits of the above integral respectively, and converting Equation (8) into the standard error function, we can get:

In equation (9), erf( ) is the error function;

For an error function of the form:

Its approximate calculation can use series expansion. The classic Taylor series expansion has a slower convergence rate than the Chebyshev series, but it has a relatively simple algebraic form, so it is widely used. For engineering research, the acquisition form is relatively simple, and the error can be expressed concisely and accepted by the engineering field, and there is no need to pursue an accurate expression with minimal error in the mathematical sense. Taylor series expansion adopts different forms according to the value range of the error function independent variable, such as:

When z≤4, erf(z) can be expanded as:

because:

When d _max /d _min is 1000:

And according to equation (11):

Therefore, when:

which is:

, Equation (9) approximately holds;

In addition, the conditions for the establishment of equation (9) are related to the size of n and d _max /d _min , and n is restricted by the size of d _max /d _min ; the cumulative probability density of bubble particle size g(n) is constructed to examine n and d The influence of _max /d _min on the establishment conditions of equation (9), let the cumulative probability density g(n) of bubble particle size be:

Draw the relational curve of g(n)～n; obtain the relationship between the range of possible values of n and d _max /d _min to ensure the establishment of equation (9);

Take the equality condition of inequality (16), namely:

Determine m and n by formulas (5) and (18), and then establish the basic mathematical model of _d32 by equation (2); the results are as follows:

(2) Based on the Kolmogorov-Hinze theory, construct the relationship between the maximum bubble diameter d _max , the minimum bubble diameter d _min and the reactor parameters of the micro-interface strengthening reactor;

For the ultra-fine bubble system, the breakage of bubbles and the formation of new bubbles occur in the bubble breakage area with a large ε. Since the energy transfer efficiency of the turbulent vortex to the gas-liquid interface has problems, the smallest scale of the turbulent vortex that can make the bubble break is Kolmogorov 11.4 to 31.4 times the scale, assuming that the magnification is 11.4, since the turbulent vortex can only break the bubbles whose diameter is larger than its scale, therefore, the minimum value of the bubble diameter d _min is consistent with the scale of the turbulent vortex, that is:

d _min ＝11.4(μ _L /ρ _L ) ^0.75 ε ^-0.25 (21)

Based on the Kolmogorov-Hinze theory, the maximum bubble diameter d _max is determined by the following formula (22):

d _max ＝ε ^-2/5 (σ _L We _crit /2ρ _L ) ^3/5 (22)

Among them, ε is the energy dissipation rate; μ _L is the liquid dynamic viscosity; σ _L is the liquid surface tension; ρ _L is the liquid density; We _crit is the critical weber number for bubble breakup;

The critical weber number We _crit used in different studies is different. This is mainly because the weber number is related to the flow pattern around the bubble, and the flow pattern is difficult to describe quantitatively. In the present invention, based on the resonance theory of bubble crushing, We _crit is determined:

Among them, α ₂ is the bulk modulus of the bubble, α ₂ =2,3,...; when α ₂ is larger, the higher-order vibration of the bubble is more intense, and the bubble is smaller. For ultra-fine bubble particles, choose α ₂ =2, That is _Wecrit = 1.24;

at this time:

d _max ＝0.75(σ _L /ρ _L ) ^0.6 ε ^-0.4 (24)

Preferably, the energy dissipation rate ε is obtained in the following manner:

Step 100: Divide the calculation of the total energy dissipation rate ε of the micro-interface strengthening reactor into the sum of the energy dissipation rates of three different regions in the micro-interface strengthening reactor, including the energy dissipation rate of the bubbling area in the main area of the reactor ε _R , ε _mix in the gas-liquid crushing zone and ε _pl in the gas-liquid outlet zone;

Step 110: Wherein, the energy dissipation rate ε _R of the bubbling zone in the main zone of the reactor is calculated as follows:

During the gas bubbling process in the reactor, according to the work done by the bubbles on the system, ε _R is expressed as:

Among them, Q _G is the ventilation volume flow rate in the reactor, m ³ /s; S ₀ is the cross-sectional area of the reactor, m ² ;

Step 120: Calculate ε _mix in the gas-liquid crushing zone:

Based on the classic calculation model of ε _mix , it is assumed that gas-liquid mixing is an adiabatic process and the change of liquid potential energy and gas mass flow are ignored, and the unit of energy dissipation rate is unified as W/Kg. The calculation formula is as follows:

Among them, L _mix is the length of the bubble breaking zone, m; P ₀ and P ₁ are the static pressure of the inlet liquid and the pressure of the gas-liquid mixture at the outlet of the bubble breaking zone, respectively, Pa; λ ₁ is the ratio of gas-liquid volume flow rate; K ₁ is the diameter of the nozzle The ratio to the diameter of the bubble breaker zone, K ₁ = D _N /D ₁ ; S ₁ is the cross-sectional area of the bubble breaker, m ² ; ρ _L is the liquid density, kg/m ³ ; Q _L is the liquid circulation volume in the reactor Flow rate, m ³ /s;

λ ₁ =Q _G /Q _L (27)

Step 121: Calculating the static pressure P ₀ of the inlet liquid of the bubble breaking zone and the pressure P ₁ of the gas-liquid mixture at the outlet:

Neglecting the friction loss of the tube wall in the bubble breaking zone, then:

Among them, φ _mix is the gas holdup in the bubble breaking zone, which is calculated by the following formula:

Neglecting pipeline friction and energy loss at the nozzle, according to the principle of energy conservation, the actual energy E ₀ obtained by the system is:

which is:

From formula (28) (31):

Step 122: Calculate the length L _mix of the bubble crushing zone:

L _mix is determined by measuring the sudden change of pressure on the inner wall of the gas-liquid crushing zone, or by the following method:

Among them: P _H is the air pressure above the gas-liquid crushing zone, Pa; ρ _MZ is the density of the gas-liquid mixture in the gas-liquid crushing zone, Kg/m ³ ; v _N is the jet velocity of the jet port, m/s; U _e,max is The maximum return speed of the vortex in the gas-liquid crushing zone, m/s;

_PH is deduced from the Bernoulli equation:

P _H ≈ P _G0 (34)

In the formula, P _G0 is the air supply pressure, Pa;

ρ _MZ is calculated by the following formula:

ρ _MZ ＝ρ _G φ _mix + ρ _L (1-φ _mix )≈ρ _L (1-φ _mix ) (35)

In the formula, ρ _G is the gas density, g/m ³ ;

Considering the influence of the flow velocity of the gas-liquid mixture in the gas-liquid crushing zone, U _e,max is the result of the vector synthesis of the jet velocity at the jet port and the flow velocity of the gas-liquid mixture in the gas-liquid crushing zone, and U e, _max is calculated using the following formula:

Substituting formula (34)(36) into formula (33) and simplifying can get:

Obtain the length L _b of the reactor bubble breaker, and calculate L _mix according to formula (37);

① When L _mix < L _b , the calculation result of formula (37) is the actual value of L _mix ;

② When L _mix ≥ L _b , it means that the jet energy is almost completely consumed in the bubble breaker area, then:

L _mix = L _b (38)

Step 130: Calculate ε _pl of the gas-liquid outlet area;

Assuming that the bubbles are uniformly distributed in the gas-liquid outlet area, the energy dissipation rate ε _pl in this area is calculated by the following formula:

When designing the reactor structure, ensure that the adjustable range of λ ₁ is large enough, and the relationship between the basic structural parameters of the reactor is determined through experiments as K ₁ =0.5, L _b =13D ₁ ; substituting the above-mentioned corresponding expression and simplifying it can be obtained:

Step 200: Determine the respective values of ε _R , ε _mix and ε _pl ;

Step 210: According to the principle that the gas-liquid flow rate entering the reactor is equal to the gas-liquid flow rate balance principle at the outlet of the bubble breaking zone, it is obtained:

In the formula, C _L is the liquid circulation multiple based on the effective volume in the reactor πD ₀ ² H ₀ /4, that is, the ratio of the total liquid circulation volume per hour to the effective volume of the reactor; u ₁ is the gas-liquid mixture line at the outlet of the bubble breaker Speed, m/s; λ ₁ takes a value of 0.1~0.5;

It can be seen from formula (43): Then when u ₁ increases, the cross-sectional area S ₀ of the reactor also increases; combined with formula (25), it can be known that ε _R decreases at this time; in order to compare the energy dissipation rates in different regions of the reactor, it is assumed that: u ₁ =3.0m/s; C _L =20; H ₀ =1.5m; from formula (43), when λ ₁ =0.1～0.5:

D ₀ ≈19D ₁ (44)

Select the value _of D1, calculate and compare the energy dissipation rate of different areas of the reactor at different nozzle liquid velocities, and determine the energy dissipation rate ε _mix of the gas-liquid crushing area, the main area of the reactor, the gas-liquid outlet area The energy dissipation rate of the reactor is negligible, that is, ε _mix ≈ε; then the mathematical relationship between the energy dissipation rate ε of the entire reactor and the structural parameters of the reactor can be determined by formula (26), namely:

The second object of the present invention is to provide a bubble-scale structure-effect control model constructed by the above modeling method.

Specifically, the bubble-scale structure-effect regulation model is as follows:

d _min ＝11.4(μ _L /ρ _L ) ^0.75 ε ^-0.25 (21)

d _max ＝0.75(σ _L /ρ _L ) ^0.6 ε ^-0.4 (24)

In the formula, Q _L is the liquid circulation volume flow rate in the reactor; L _mix is the length of the bubble breaking zone; D ₁ is the diameter of the bubble breaking tube; λ ₁ is the ratio of gas-liquid volume flow rate, λ ₁ =Q _G /Q _L ; Q _G is the ventilation volume flow rate in the reactor; P ₀ is the static pressure of the liquid at the inlet of the bubble breaker; P ₁ is the pressure of the gas-liquid mixture at the outlet of the bubble breaker; ε is the energy dissipation rate; μ _L is the dynamic viscosity of the liquid; σ _L is the surface tension of the liquid; ρ _L is the density of the liquid.

Another object of the present invention is to provide the application of the above method in reactor design.

According to the value of the average bubble Sauter diameter d ₃₂ , through the relationship between the reactor structure parameters, physical property parameters, operating conditions and bubble Sauter average diameter d ₃₂ established by the above-mentioned bubble scale structure-effect control model, the structural parameters and physical property parameters of the reactor were adjusted. Design, so that the structural parameters and physical parameters of the reactor conform to the numerical relationship determined by the bubble-scale structure-effect control model.

The method of the invention is suitable for micro-interface intensified reactors, the core of which is a bubble breaker. The principle of the bubble breaker is that the gas carried by the high-speed jet collides with each other for energy transfer to break the bubbles. Its structural parameters are L _b and D ₁ . The detailed structure is shown in Figure 1. In addition, other structural parameters of the reactor There are D ₀ and H ₀ , and the relevant content of the specific reactor structure has been published in the patent CN10618766A previously applied by the inventor, and will not be repeated in the present invention.

The present invention has following beneficial effects:

(1) The bubble-scale structure-effect regulation model constructed by the modeling method of the present invention constructs the direct calculation relationship of _dmax , _dmin and _d32 , instead of using the experimental fitting method to obtain the specific value of _d32 , Greatly reduces the error when applied in the reactor;

(2) The d ₃₂ model constructed by the existing method is mostly aimed at the gas-liquid system in the bubble reactor (Bubble column, BC) and the bubble stirred tank reactor (Bubbling-stirred reactor, BSR), or the jet pump (gas-liquidjet bump, GLJB) in the air-water system. And for industrial microinterface reactor (MIR), it is not necessarily applicable, and its reason is that: 1. the mechanism of bubble breakup in MIR is different from the above-mentioned reactor; 2. high viscosity liquid may be involved in the industrial gas-liquid reaction system, and the (such as formula 46) does not consider the influence of liquid viscosity on d ₃₂ ; and the bubble-scale structure-effect control model constructed by the modeling method of the present invention can be applied to industrial microinterface reactor (MIR), and its versatility is better;

(3) The bubble-scale structure-efficiency control model constructed by the modeling method of the present invention can further obtain the maximization target of the energy efficiency and material efficiency of the reaction process by adjusting the structural parameters and operating parameters of the reactor, or in a given reaction target ( Task) and energy and material consumption, design an efficient reactor structure.

Description of drawings

Fig. 1 is a kind of reactor structure schematic diagram, is used to illustrate the application of modeling method of the present invention in reactor device; Wherein 1-reactor, 2-pump front valve, 3-circulation pump, 4-pump rear valve, 5 - Liquid flow meter, 6- heat exchanger, 7- bubble breaker, 8- thermometer, 9- downcomer, 10- gas valve, 11- gas flow meter, 12- gas phase inlet, 13- pressure gauge, 14 - liquid level gauge; D ₀ - diameter of reactor, H ₀ - initial liquid level height in reactor, D ₁ - diameter of bubble breaking tube, L _b - length of bubble breaking zone;

Figure 2 is a graph showing the influence of n and d _max /d _min on the cumulative probability density of bubble particle size;

Fig. 3 is a comparison graph of calculation results between the prior art and the present invention.

detailed description

Example 1

This embodiment specifically illustrates the modeling method of the bubble scale model of the present invention.

The method of the present invention comprises:

(1) Taking the maximum bubble diameter d _max and the minimum bubble diameter d _min of the micro-interface strengthening reactor as independent variables, and the bubble Sauter average diameter d ₃₂ as the dependent variable, establish the relationship between d _max , d _min and d ₃₂ ; the specific steps are as follows :

Let x, m, and n be the mean and standard deviation of the bubble particle size and the geometric natural logarithm of the bubble particle size in the gas-liquid system of the reactor, respectively, and obtain the probability density function of the bubble particle size x:

The bubble Sauter average diameter d ₃₂ when the bubble particle size satisfies this distribution is:

d ₃₂ ＝exp(m+2.5n ² ) (2)

The bubble size x is log-normally distributed, so the mathematical expectation (arithmetic mean) of lnx is: According to the probability density function of the bubble particle size x, the probability density map of the bubble particle size is drawn, when When , the probability density is the largest; that is, the first derivative here is 0:

Substituting equation (3) into (1) yields equation (4):

From (3), (4) can get:

because:

After substituting equation (1) into (6) and simplifying, we get:

make: Then the above formula simplifies to:

The left end of Equation (8) is the error function, and the difference with the standard error function lies in the difference of the integral limit. Substituting Equation (5) into the upper and lower limits of the above integral respectively, and converting Equation (8) into the standard error function, we can get:

In equation (9), erf( ) is the error function;

For an error function of the form:

Its approximate calculation can use series expansion. The classic Taylor series expansion has a slower convergence rate than the Chebyshev series, but it has a relatively simple algebraic form, so it is widely used. For engineering research, the acquisition form is relatively simple, and the error can be expressed concisely and accepted by the engineering field, and there is no need to pursue an accurate expression with minimal error in the mathematical sense. Taylor series expansion adopts different forms according to the value range of the error function independent variable, such as:

When z≤4, erf(z) can be expanded as:

because:

When d _max /d _min is 1000:

And according to equation (11):

Therefore, when:

which is:

, Equation (9) approximately holds;

In addition, the conditions for the establishment of equation (9) are related to the size of n and d _max /d _min , and n is restricted by the size of d _max /d _min ; the cumulative probability density of bubble particle size g(n) is constructed to examine n and d The influence of _max /d _min on the establishment conditions of equation (9), let the cumulative probability density g(n) of bubble particle size be:

Draw g(n)～n relationship curve, as shown in Figure 2; for a certain gas-liquid system, the bubble particle size distribution (determined by m and n) is affected by d _max /d _min ; when d _max /d _min- Timing, n should have a unique value, that is, the bubble size distribution is unique. It can be seen from Figure 2 that the range of possible values of n that ensures the establishment of equation (9) is closely related to d _max /d _min , but when n→0, n has nothing to do with d _max /d _min ;

Take the equality condition of inequality (16), namely:

Determine m and n by formulas (5) and (18), and then establish the basic mathematical model of _d32 by equation (2); the results are as follows:

(2) Based on the Kolmogorov-Hinze theory, construct the relationship between the maximum bubble diameter d _max , the minimum bubble diameter d _min and the reactor parameters of the micro-interface strengthening reactor;

For the ultra-fine bubble system, the breakage of bubbles and the formation of new bubbles occur in the bubble breakage area with a large ε. Since the energy transfer efficiency of the turbulent vortex to the gas-liquid interface has problems, the smallest scale of the turbulent vortex that can make the bubble break is Kolmogorov 11.4 to 31.4 times the scale, assuming that the magnification is 11.4, since the turbulent vortex can only break the bubbles whose diameter is larger than its scale, therefore, the minimum value of the bubble diameter d _min is consistent with the scale of the turbulent vortex, that is:

d _min ＝11.4(μ _L /ρ _L ) ^0.75 ε ^-0.25 (21)

Based on the Kolmogorov-Hinze theory, the maximum bubble diameter d _max is determined by the following formula (22):

d _max ＝ε ^-2/5 (σ _L We _crit /2ρ _L ) ^3/5 (22)

Among them, ε is the energy dissipation rate; μ _L is the liquid dynamic viscosity; σ _L is the liquid surface tension; ρ _L is the liquid density; We _crit is the critical weber number for bubble breakup;

The critical weber number We _crit used in different studies is different. This is mainly because the weber number is related to the flow pattern around the bubble, and the flow pattern is difficult to describe quantitatively. In the present invention, based on the resonance theory of bubble crushing, We _crit is determined:

Among them, α ₂ is the bulk modulus of the bubble, α ₂ =2,3,...; when α ₂ is larger, the higher-order vibration of the bubble is more intense, and the bubble is smaller. For ultra-fine bubble particles, choose α ₂ =2, That is _Wecrit = 1.24;

at this time:

d _max ＝0.75(σ _L /ρ _L ) ^0.6 ε ^-0.4 (24)

Among them, the energy dissipation rate ε is calculated as follows:

Among them, step 100: the calculation of the total energy dissipation rate ε of the micro-interface strengthening reactor is divided into the sum of the energy dissipation rates of three different regions in the micro-interface strengthening reactor, including the energy consumption of the bubbling area in the main area of the reactor Dispersion rate ε _R , ε _mix in the gas-liquid crushing zone and ε _pl in the gas-liquid outlet zone;

Step 110: Wherein, the energy dissipation rate ε _R of the bubbling zone in the main zone of the reactor is calculated as follows:

During the gas bubbling process in the reactor, according to the work done by the bubbles on the system, ε _R is expressed as:

Among them, Q _G is the ventilation volume flow rate in the reactor, m ³ /s; S ₀ is the cross-sectional area of the reactor, m ² ;

Step 120: Calculate ε _mix in the gas-liquid crushing zone:

Based on the classic calculation model of ε _mix , it is assumed that gas-liquid mixing is an adiabatic process and the change of liquid potential energy and gas mass flow are ignored, and the unit of energy dissipation rate is unified as W/Kg. The calculation formula is as follows:

Among them, L _mix is the length of the bubble breaking zone, m; P ₀ and P ₁ are the static pressure of the inlet liquid and the pressure of the gas-liquid mixture at the outlet of the bubble breaking zone, respectively, Pa; λ ₁ is the ratio of gas-liquid volume flow rate; K ₁ is the diameter of the nozzle The ratio to the diameter of the bubble breaker zone, K ₁ = D _N /D ₁ ; S ₁ is the cross-sectional area of the bubble breaker, m ² ; ρ _L is the liquid density, kg/m ³ ; Q _L is the liquid circulation volume in the reactor Flow rate, m ³ /s;

λ ₁ =Q _G /Q _L (27)

Step 121: Calculating the static pressure P ₀ of the inlet liquid of the bubble breaking zone and the pressure P ₁ of the gas-liquid mixture at the outlet:

Neglecting the friction loss of the tube wall in the bubble breaking zone, then:

Among them, φ _mix is the gas holdup in the bubble breaking zone, which is calculated by the following formula:

Neglecting pipeline friction and energy loss at the nozzle, according to the principle of energy conservation, the actual energy E ₀ obtained by the system is:

which is:

From formula (28) (31):

Step 122: Calculate the length L _mix of the bubble crushing zone:

L _mix is determined by measuring the sudden change of pressure on the inner wall of the gas-liquid crushing zone, or by the following method:

Among them: P _H is the air pressure above the gas-liquid crushing zone, Pa; ρ _MZ is the density of the gas-liquid mixture in the gas-liquid crushing zone, Kg/m ³ ; v _N is the jet velocity of the jet port, m/s; U _e,max is The maximum return speed of the vortex in the gas-liquid crushing zone, m/s;

_PH is deduced from the Bernoulli equation:

P _H ≈ P _G0 (34)

In the formula, P _G0 is the air supply pressure, Pa;

ρ _MZ is calculated by the following formula:

ρ _MZ ＝ρ _G φ _mix + ρ _L (1-φ _mix )≈ρ _L (1-φ _mix ) (35)

In the formula, ρ _G is the gas density, g/m ³ ;

Considering the influence of the flow velocity of the gas-liquid mixture in the gas-liquid crushing zone, U _e,max is the result of the vector synthesis of the jet velocity at the jet port and the flow velocity of the gas-liquid mixture in the gas-liquid crushing zone, and U e, _max is calculated using the following formula:

Substituting formula (34)(36) into formula (33) and simplifying can get:

Obtain the length L _b of the reactor bubble breaker, and calculate L _mix according to formula (37);

① When L _mix < L _b , the calculation result of formula (37) is the actual value of L _mix ;

② When L _mix ≥ L _b , it means that the jet energy is almost completely consumed in the bubble breaker area, then:

L _mix = L _b (38)

Step 130: Calculate ε _pl of the gas-liquid outlet area;

Assuming that the bubbles are uniformly distributed in the gas-liquid outlet area, the energy dissipation rate ε _pl in this area is calculated by the following formula:

When designing the reactor structure, ensure that the adjustable range of λ ₁ is large enough, and the relationship between the basic structural parameters of the reactor is determined through experiments as K ₁ =0.5, L _b =13D ₁ ; substituting the above-mentioned corresponding expression and simplifying it can be obtained:

Step 200: Determine the respective values of ε _R , ε _mix and ε _pl ;

Step 210: According to the principle that the gas-liquid flow rate entering the reactor is equal to the gas-liquid flow rate balance principle at the outlet of the bubble breaking zone, it is obtained:

In the formula, C _L is the liquid circulation multiple based on the effective volume in the reactor πD ₀ ² H ₀ /4, that is, the ratio of the total liquid circulation volume per hour to the effective volume of the reactor; u ₁ is the gas-liquid mixture line at the outlet of the bubble breaker Speed, m/s; λ ₁ takes a value of 0.1 to 0.5;

It can be known from formula (43): Then when u ₁ increases, the cross-sectional area S ₀ of the reactor also increases; combined with formula (25), it can be seen that ε _R decreases at this time; in order to compare the energy dissipation rates of different regions of the reactor, it is assumed that: u ₁ =3.0m/s; C _L =20; H ₀ =1.5m; from formula (43), when λ ₁ =0.1～0.5:

D ₀ ≈19D ₁ (44)

Select the value _of D1, calculate and compare the energy dissipation rate of different areas of the reactor at different nozzle liquid velocities, and determine the energy dissipation rate ε _mix of the gas-liquid crushing area, the main area of the reactor, the gas-liquid outlet area The energy dissipation rate of the reactor is negligible, that is, ε _mix ≈ε; then the mathematical relationship between the energy dissipation rate ε of the entire reactor and the structural parameters of the reactor can be determined by formula (26), namely:

Example 2

In this example, the reactor shown in FIG. 1 is taken as an example to illustrate the application of the model constructed by the modeling method described in Example 1 in the carbon dioxide and water system reactor. The reactor structure in Fig. 1 can be the structure of the existing micro-interface strengthening reactor, and only the method of the present invention is used for parameter design, and the structure of the reactor will not be repeated in the present invention.

The bubble-scale structure-effect control model constructed according to Example 1 is as follows:

d _min ＝11.4(μ _L /ρ _L ) ^0.75 ε ^-0.25 (21)

d _max ＝0.75(σ _L /ρ _L ) ^0.6 ε ^-0.4 (24)

In the formula, Q _L is the liquid circulation volume flow rate in the reactor; L _mix is the length of the bubble breaking zone; D ₁ is the diameter of the bubble breaking tube; λ ₁ is the ratio of gas-liquid volume flow rate, λ ₁ =Q _G /Q _L ; Q _G is the ventilation volume flow rate in the reactor; P ₀ is the static pressure of the liquid at the inlet of the bubble breaker; P ₁ is the pressure of the gas-liquid mixture at the outlet of the bubble breaker; ε is the energy dissipation rate; μ _L is the dynamic viscosity of the liquid; σ _L is the surface tension of the liquid; ρ _L is the density of the liquid.

The model selected in Example 3 mainly considers the situation that L _mix is smaller than L _b , because the opposite situation is uncommon and rather extreme. The structural parameters of the reactor also need to meet: λ ₁ =0.1～0.5, K ₁ =0.5, L _b =13D ₁ ;

For the carbon dioxide and water system, when the operating conditions are: Q _L =2000L/h (5.56×10 ^-4 m ³ /s), gas flow rate Q _G =0.2Q _L , T=298K, P _G0 =1atm; and this system The physical parameters of the middle liquid phase are: ρ _L =1000kg/m ³ , μ _L =8.9×10 ^-4 Pa·s, σ _L =7.197×10 ^-4 N/m; the diameter of the reactor bubble breaker tube D ₁ =0.02 m; E ₀ represents the energy input by the system, that is, the rated power on the nameplate of the circulating pump, and E ₀ =1000W.

According to the operating conditions and the above model, the average Sauter diameter of bubbles can be calculated as d ₃₂ =0.426 mm, while the average diameter of bubbles obtained under traditional process conditions is about 1 mm. It can be seen that the average diameter of bubbles in this reactor is more than twice as small as the average diameter of bubbles produced in a conventional reactor.

According to Levenspiel, the macroscopic reaction rate of a heterogeneous system can be expressed by the following formula:

The simplified gas-liquid reaction macroscopic rate equation can be simplified as:

Table 1 and Table 2 are the comparison of each parameter under different particle sizes of the same system:

Table 1 Parameters calculated by the model formula under different particle sizes

Table 2 Three kinds of resistance (air film, liquid film, intrinsic) calculated by the model formula under different particle sizes

As shown in Table 1 and Table 2, when the bubble diameter becomes 1/10 and 1/2 of the original, the gas-liquid interface area increases by about 467 times and 9 times, respectively, and the macroscopic reaction rate increases by about 4 times and 2 times, and the reaction resistance is gradually transitioned from being controlled by the liquid film to being controlled by the intrinsic reaction resistance. It can be seen that the microbubble scale does enhance the gas-liquid mass transfer rate.

Example 3

This embodiment takes the reactor shown in Figure 1 as an example to illustrate the application of the model constructed by the modeling method described in Example 1 in the air-water system reactor, and its superiority compared with the existing prediction d ₃₂ model .

For the air-water system, the prior art generally uses the following formula to predict d ₃₂ :

d ₃₂ =0.65d _max (46)

Construct the above formula and the d ₃₂ prediction formula calculation result comparison curve constructed by the method of the present invention, as shown in Figure 3. It can be seen from Fig. 3 that when the energy dissipation rate ε is small enough (ε is less than 10(W/kg), the calculation results of this study and formula (46) are basically consistent; when ε gradually increases, the prediction results of the two have the same A certain difference: For the air-water system, when ε is greater than 10 (W/kg), the result obtained by formula (46) is relatively small, but the error between the two is acceptable.

The disadvantages of formula (46) are: 1. The coefficients in this equation are obtained based on experimental fitting and cannot be related to the reactor design parameters; 2. The mathematical expression of d _max in the equation is obtained based on isotropic turbulence theory , and the premise that this theory is applicable is that the energy dissipation rate is infinite, at this time, the influence of liquid viscosity on the bubble size can be ignored. In recent years, the bubble particle size distribution of the full energy spectrum has been studied, but the form is relatively complex, and there are some empirical parameters in it, so it is still necessary to further simplify the form and determine the model parameters reasonably.

And the method of the present invention is also obtained based on the isotropic turbulent flow theory, but by the probability statistics analysis to the bubble particle size distribution, the relational expression obtained by reasonable mathematical processing is related to the liquid viscosity, which has a certain effect on the size of the bubbles in the industrial reactor. The important physical parameters can be used as the basis for further industrial applications.

Claims (5)

1. A method for modeling a bubble-scale structure-effect regulation model of a micro-interface strengthening reactor, characterized in that it comprises: (1) Taking the maximum bubble diameter d _max and the minimum bubble diameter d _min of the micro-interface strengthening reactor as independent variables, and the bubble Sauter average diameter d ₃₂ as the dependent variable, establish the relationship between d _max , d _min and d ₃₂ ; the specific steps are as follows : Let x, m, and n be the mean and standard deviation of the bubble particle size and the geometric natural logarithm of the bubble particle size in the gas-liquid system of the reactor, respectively, and obtain the probability density function of the bubble particle size x: The bubble Sauter average diameter d ₃₂ when the bubble particle size satisfies this distribution is: d ₃₂ ＝exp(m+2.5n ² ) (2) The bubble size x is log-normally distributed, so the mathematical expectation (arithmetic mean) of lnx is: According to the probability density function of the bubble particle size x, the probability density map of the bubble particle size is drawn, when When , the probability density is the largest; that is, the first derivative here is 0: Substituting equation (3) into (1) yields equation (4): From (3), (4) can get: because: After substituting equation (1) into (6) and simplifying, we get: make: Then the above formula simplifies to: The left end of Equation (8) is the error function, and the difference with the standard error function lies in the difference of the integral limit. Substituting Equation (5) into the upper and lower limits of the above integral respectively, and converting Equation (8) into the standard error function, we can get: In equation (9), erf( ) is the error function; For an error function of the form: The Taylor series expansion is used for approximate calculation. The Taylor series expansion adopts different forms according to the value range of the independent variable of the error function. When z≤4, erf(z) can be expanded as: because: When d _max /d _min is 1000: And according to equation (11): Therefore, when: which is: , Equation (9) approximately holds; In addition, the conditions for the establishment of equation (9) are related to the size of n and d _max /d _min , and n is restricted by the size of d _max /d _min ; the cumulative probability density g(n) of bubble particle size is constructed to examine n and d The influence of _max /d _min on the establishment conditions of equation (9), let the cumulative probability density g(n) of bubble particle size be: Draw the relational curve of g(n)～n; obtain the relationship between the range of possible values of n and d _max /d _min to ensure the establishment of equation (9); Take the equality condition of inequality (16), namely: Determine m and n by formulas (5) and (18), and then establish the basic mathematical model of _d32 by equation (2); the results are as follows: (2) Based on the Kolmogorov-Hinze theory, construct the relationship between the maximum bubble diameter d _max , the minimum bubble diameter d _min and the reactor parameters of the micro-interface strengthening reactor; The smallest turbulent vortex scale that can break bubbles is 11.4 to 31.4 times the Kolmogorov scale. Assuming that the magnification is 11.4, since the turbulent vortex can only break bubbles whose diameter is larger than its size, the minimum value of the bubble diameter d _min is the same as the turbulent vortex scale Consistent, that is: d _min ＝11.4(μ _L /ρ _L ) ^0.75 ε ^-0.25 (21) Based on the Kolmogorov-Hinze theory, the maximum bubble diameter d _max is determined by the following formula (22): d _max ＝ε ^-2/5 (σ _L We _crit /2ρ _L ) ^3/5 (22) Among them, ε is the energy dissipation rate; μ _L is the liquid dynamic viscosity; σ _L is the liquid surface tension; ρ _L is the liquid density; We _crit is the critical weber number for bubble breakup; We _crit is determined based on the resonance theory of bubble crushing: Among them, α ₂ is the bulk modulus of the bubble, α ₂ =2,3,...; when α ₂ is larger, the higher-order vibration of the bubble is more intense, and the bubble is smaller. For ultra-fine bubble particles, choose α ₂ =2, That is _Wecrit = 1.24; at this time: d _max ＝0.75(σ _L /ρ _L ) ^0.6 ε ^-0.4 (24) According to formulas (20), (21) and (24), the average Sauter diameter d ₃₂ of the bubbles is calculated. 2. The method according to claim 1, wherein the energy dissipation rate ε is obtained in the following manner: Step 100: Divide the calculation of the total energy dissipation rate ε of the micro-interface strengthening reactor into the sum of the energy dissipation rates of three different regions in the micro-interface strengthening reactor, including the energy dissipation rate of the bubbling area in the main area of the reactor ε _R , ε _mix in the gas-liquid crushing zone and ε _pl in the gas-liquid outlet zone; Step 110: Wherein, the energy dissipation rate ε _R of the bubbling zone in the main zone of the reactor is calculated as follows: During the gas bubbling process in the reactor, according to the work done by the bubbles on the system, ε _R is expressed as: Among them, Q _G is the ventilation volume flow rate in the reactor, m ³ /s; S ₀ is the cross-sectional area of the reactor, m ² ; Step 120: Calculate ε _mix in the gas-liquid crushing zone: Based on the classic calculation model of ε _mix , it is assumed that gas-liquid mixing is an adiabatic process and the change of liquid potential energy and gas mass flow are ignored, and the unit of energy dissipation rate is unified as W/Kg. The calculation formula is as follows: Among them, L _mix is the length of the bubble breaking zone, m; P ₀ and P ₁ are the static pressure of the inlet liquid and the pressure of the gas-liquid mixture at the outlet of the bubble breaking zone, respectively, Pa; λ ₁ is the ratio of gas-liquid volume flow rate; K ₁ is the diameter of the nozzle The ratio to the diameter of the bubble breaker zone, K ₁ = D _N /D ₁ ; S ₁ is the cross-sectional area of the bubble breaker, m ² ; ρ _L is the liquid density, kg/m ³ ; Q _L is the liquid circulation volume in the reactor Flow rate, m ³ /s; λ ₁ =Q _G /Q _L (27) Step 121: Calculating the static pressure P ₀ of the inlet liquid of the bubble breaking zone and the pressure P ₁ of the gas-liquid mixture at the outlet: Neglecting the friction loss of the tube wall in the bubble breaking zone, then: Among them, φ _mix is the gas holdup in the bubble breaking zone, which is calculated by the following formula: Neglecting pipeline friction and energy loss at the nozzle, according to the principle of energy conservation, the actual energy E ₀ obtained by the system is: which is: From formula (28) (31): Step 122: Calculate the length L _mix of the bubble crushing zone: L _mix is determined by measuring the sudden change of pressure on the inner wall of the gas-liquid crushing zone, or by the following method: Among them: P _H is the air pressure above the gas-liquid crushing zone, Pa; ρ _MZ is the density of the gas-liquid mixture in the gas-liquid crushing zone, Kg/m ³ ; v _N is the jet velocity of the jet port, m/s; U _e,max is The maximum return speed of the vortex in the gas-liquid crushing zone, m/s; _PH is deduced from the Bernoulli equation: P _H ≈ P _G0 (34) In the formula, P _G0 is the air supply pressure, Pa; ρ _MZ is calculated by the following formula: ρ _MZ ＝ρ _G φ _mix + ρ _L (1-φ _mix )≈ρ _L (1-φ _mix ) (35) In the formula, ρ _G is the gas density, g/m ³ ; Considering the influence of the flow velocity of the gas-liquid mixture in the gas-liquid crushing zone, U _e,max is the result of the vector synthesis of the jet velocity at the jet port and the flow velocity of the gas-liquid mixture in the gas-liquid crushing zone, and U e, _max is calculated using the following formula: Substituting formula (34)(36) into formula (33) and simplifying can get: Obtain the length L _b of the reactor bubble breaker, and calculate L _mix according to formula (37); ① When L _mix < L _b , the calculation result of formula (37) is the actual value of L _mix ; ② When L _mix ≥ L _b , it means that the jet energy is almost completely consumed in the bubble breaker area, then: L _mix = L _b (38) Step 130: Calculate ε _pl of the gas-liquid outlet area; Assuming that the bubbles are uniformly distributed in the gas-liquid outlet area, the energy dissipation rate ε _pl in this area is calculated by the following formula: When designing the reactor structure, ensure that the adjustable range of λ ₁ is large enough, and the relationship between the basic structural parameters of the reactor is determined through experiments as K ₁ =0.5, L _b =13D ₁ ; substituting the above-mentioned corresponding expression and simplifying it can be obtained: Step 200: Determine the respective values of ε _R , ε _mix and ε _pl ; Step 210: According to the principle that the gas-liquid flow rate entering the reactor is equal to the gas-liquid flow rate balance principle at the outlet of the bubble breaking zone, it is obtained: In the formula, C _L is the liquid circulation multiple based on the effective volume in the reactor πD ₀ ² H ₀ /4, that is, the ratio of the total liquid circulation volume per hour to the effective volume of the reactor; u ₁ is the gas-liquid mixture line at the outlet of the bubble breaker Speed, m/s; λ ₁ takes a value of 0.1 to 0.5; It can be known from formula (43): Then when u ₁ increases, the cross-sectional area S ₀ of the reactor also increases; combined with formula (25), it can be seen that ε _R decreases at this time; in order to compare the energy dissipation rates of different regions of the reactor, it is assumed that: u ₁ =3.0m/s; C _L =20; H ₀ =1.5m; from formula (43), when λ ₁ =0.1～0.5: D ₀ ≈19D ₁ (44) Select the value _of D1, calculate and compare the energy dissipation rate of different areas of the reactor at different nozzle liquid velocities, and determine the energy dissipation rate ε _mix of the gas-liquid crushing area, the main area of the reactor, the gas-liquid outlet area The energy dissipation rate of the reactor is negligible, that is, ε _mix ≈ε; then the mathematical relationship between the energy dissipation rate ε of the entire reactor and the structural parameters of the reactor can be determined by formula (26), namely: . 3. the bubble-scale structure-effect regulation and control model that the method described in claim 2 builds, it is characterized in that, the bubble-scale structure-effect regulation and control model of construction is as follows: d _min ＝11.4(μ _L /ρ _L ) ^0.75 ε ^-0.25 (21) d _max ＝0.75(σ _L /ρ _L ) ^0.6 ε ^-0.4 (24) In the formula, Q _L is the liquid circulation volume flow rate in the reactor; L _mix is the length of the bubble breaking zone; D ₁ is the diameter of the bubble breaking tube; λ ₁ is the ratio of gas-liquid volume flow rate, λ ₁ =Q _G /Q _L ; Q _G is the ventilation volume flow rate in the reactor; P ₀ is the static pressure of the liquid at the inlet of the bubble breaker; P ₁ is the pressure of the gas-liquid mixture at the outlet of the bubble breaker; ε is the energy dissipation rate; μ _L is the dynamic viscosity of the liquid; σ _L is the surface tension of the liquid; ρ _L is the density of the liquid. 4. Application of the method according to claim 1 or 2 in reactor design. 5. application according to claim 4, it is characterized in that, according to required air bubble Sauter average diameter d ₃₂ value, the reactor structure parameter, physical property parameter, operating condition and air bubble Sauter average value established by above-mentioned air bubble scale structure-effect control model Diameter d ₃₂ relationship, design the structural parameters and physical property parameters of the reactor, so that the structural parameters and physical property parameters of the reactor conform to the numerical relationship determined by the bubble-scale structure-effect control model.