CN111359539A - Gas-liquid reaction method and gas-liquid reaction device capable of entering reaction preparation state in advance - Google Patents

Abstract

The invention discloses a gas-liquid reaction method for entering a reaction preparation state in advance. The gas-phase feed is branched into partial gas-phase feed and main process gas-phase feed; The premixing is completed in 4 steps to obtain the premixed material; the lower part of the reactor is provided with the main process gas phase inlet and the premixed material inlet, and the reactor above the premixed material inlet is the main reaction control unit; the premixed material It enters the reactor through the premixed material feed port, and the main process gas phase feed enters the reactor through the main process gas phase feed port, and enters the reaction main control unit with the premixed material upward for reaction. Also provided is a gas-liquid reaction device. The above-mentioned gas-liquid reaction method and device can make the premixed material enter the reaction preparation state in advance before entering the reactor, which is beneficial to improve the conversion rate and selectivity to approach the reaction equilibrium conversion rate and selectivity.

Description

Gas-liquid reaction method and gas-liquid reaction device for entering reaction preparation state in advance

technical field

The invention belongs to the technical field of gas-liquid reaction. Specifically, it relates to a gas-liquid reaction method and a gas-liquid reaction device for entering a reaction preparation state in advance.

Background technique

In the process of medium-speed and slow gas-liquid reactions such as oxidation and hydrogenation, the gas first contacts the liquid, and the gas molecules are transferred to the liquid film at the gas-liquid interface, and further diffuse into the liquid phase to complete the dissolution process. The gas molecules dissolved in the liquid react with the liquid molecules at the catalytically active site to complete the reaction conversion process; when there is no catalytically active site, the gas can be dissolved and react with the liquid at the same time. Therefore, in the gas-liquid reaction, the speed and depth of the gas dissolved in the liquid are important links that affect the reaction speed and depth of the reaction chain.

For example, in the liquid-phase hydrogenation process, hydrogen and feedstock oil are premixed to dissolve the hydrogen in the feedstock oil, and then enter the reactor for reaction. Most of the hydrogen required in the reaction comes from the dissolved hydrogen. The similar compatibility between raw oil and hydrogen is low, so the process of dissolving hydrogen in raw oil is a relatively slow process and requires a long pre-mixing residence time. In the prior art method, in order to meet the amount of hydrogen required in the hydrogenation process, a large amount of circulating oil or additional solvent needs to be used to dissolve the hydrogen, resulting in reduced hydrogenation efficiency and high production cost.

For example, in the process of synthesizing isophthalic acid by oxidation reaction, the liquid raw material of m-xylene is mixed and contacted with oxygen in the reactor, and the reaction is carried out by mixing means such as stirring and jet flow. However, the dissolution rate and dissolved concentration of oxygen in m-xylene are very low, and the m-xylene liquid feedstock flowing directly into the reactor through the feed pipe usually needs to be pre-contacted with bubbling oxygen for a long time, resulting in the bottom of the reactor. The reaction efficiency is low, the reactor is bulky, and the production cost is high.

Patent CN 101993721A discloses a liquid-phase circulating hydrotreating method and a reaction system, which utilizes a part of the liquid-phase product of the hydroprocessing to be mixed with fresh raw material oil to form a liquid-phase material, and hydrogen is mixed into the liquid-phase material, thereby improving the mixing of hydrogen into the liquid-phase material. and saturated dissolved hydrogen. However, there is still a large amount of hydrogen surplus in the hydrogenation reactor, and a higher circulating hydrogen compressor is required to circulate the surplus hydrogen, which leads to an increase in production costs.

At present, there is a problem of insufficient dissolved gas in the liquid at the feed site of the gas-liquid reactor, so that the gas-liquid mixture there does not enter the reaction preparation state, resulting in the problem of low reaction efficiency. Therefore, there is an urgent need to develop a new gas-liquid reaction method and device to solve the above-mentioned technical defects in the prior art.

SUMMARY OF THE INVENTION

The first object of the present invention is to provide a gas-liquid reaction method that enters the reaction preparation state in advance, so as to solve the problem that the reactor in the prior art has low gas content, low reaction conversion rate and selectivity, and high production cost technical defects.

In order to achieve the above object, the present invention adopts the following technical solutions:

The gas-liquid reaction method that enters the reaction preparation state in advance, the gas-phase feed is branched into partial gas-phase feed and main-flow gas-phase feed, the lower part of the reactor is provided with the main-flow gas-phase feed port, and the main-flow gas-phase feed port is provided in the lower part of the reactor. A premixed material feeding port is arranged above, and the reactor above the premixed material feeding port is the reaction main control unit; it includes the following steps:

(1), make described part gas-phase feed to first form larger bubbles inside described liquid-phase feed, obtain the mixed feed containing larger bubbles;

(2), make the described mixed feed containing larger bubbles form a relatively strong liquid phase turbulence, so that the larger bubbles in the described mixed feed containing larger bubbles are quickly dissolved into the liquid phase, A mixed feed with more dissolved gas is obtained;

(3), make the larger bubbles that are not dissolved in the mixed feed with more gas dissolution amount to form micro-bubbles under high shear conditions, and obtain the mixed feed containing micro-bubbles;

(4), forming a relatively weak liquid phase turbulence in the mixed feed containing fine air bubbles, so that the fine air bubbles are further dissolved into the liquid phase feed to obtain the premixed material;

(5), the premixed material enters the reactor through the premixed material feed port, and the main process gas phase feed enters the reactor through the main process gas phase feed port, and upwards Entering the reaction main control unit with the premixed material to react;

Under the relatively strong liquid phase turbulence condition, the Reynolds number of the liquid is 2000-200000;

Under the relatively weak liquid phase turbulence condition, the Reynolds number of the liquid is 0.1 to 2000;

The particle Reynolds number of the fine bubbles is less than 1;

In a unit time, the amount of the part of the gas phase feed is 1.01-2 times the gas phase amount required to make the liquid phase feed reach the gas-phase saturated dissolved concentration.

Under the above conditions, the gas phase concentration in the premixed material can all reach the saturated dissolved concentration.

It should be noted that the saturated dissolved concentration is not limited to the stoichiometrically accurate saturated dissolved concentration under specific temperature and pressure conditions. Under certain temperature and pressure conditions, there will be a certain deviation in the saturated dissolved concentration in the flowing state. Typically, the offset range is ±15%. For example, the literature "Offset of the pressure of carbon dioxide-water phase equilibrium system under turbulent state," Journal of Beijing University of Chemical Technology (Natural Science Edition), 2013, 40(3): 5-11 pointed out that the offset range is ±15%.

It should be noted that it is well known to those skilled in the art that gas dissolves slowly in liquid and has insufficient depth. The limit of gas-liquid mass transfer is the gas-liquid phase equilibrium at rest. However, in the actual production process, it is difficult for the flowing gas-liquid two phases to reach the gas-liquid equilibrium. One of the reasons for this phenomenon is that the gas-liquid two phases need a long contact time to reach the dissolution equilibrium. The material cannot meet the dissolution for such a long time, so the solvent balance cannot be reached. In engineering research, researchers realized that the flowing gas-liquid two-phase can hardly reach phase equilibrium (see interface imbalance theory: Ma Youguang, Feng Huisheng, Xu Shichang, et al. Interfacial mass transfer mechanism of absorption process [J]. China Chemistry Chinese Journal of Engineering (English version), 2003, 11(2): 13-16. Ma Youguang, Yu Guocong. Mechanism of mass transfer at the gas-liquid interface [J]. Chinese Journal of Chemical Engineering, 2005, 56(4): 574-578.), can not reach Phases in equilibrium but in a relatively stable state are called thermodynamically metastable equilibrium states.

Based on the dynamic gas-liquid mass transfer theory, the liquid flow will affect the gas-liquid mass transfer rate and equilibrium concentration. The most common practice is to increase the mass transfer interface area and reduce the mass transfer resistance to accelerate the dissolution of the gas. For example, increasing the liquid phase turbulence to increase the mass transfer rate of dissolution absorption and strengthening the gas absorption, such as stirring, vibration, jet flow, supergravity and other methods, but too strong liquid phase turbulence is not conducive to dissolution absorption mass transfer, such as Carbonated beverages can cause gas desorption and spillage, and some volatile liquids usually require careful handling to avoid vaporization of the components. Therefore, how to achieve a thermodynamically metastable equilibrium state of gas-liquid two-phase under dynamic conditions under short contact time conditions, so as to improve the reaction efficiency of subsequent reactions, improve conversion rate and selectivity, and reduce production costs, is a matter for those skilled in the art. Urgent problems.

And by the above-mentioned method of the present invention, through the two steps of high-speed flow channel dissolution and low-speed flow channel dissolution, the dissolution and absorption of the gas is strengthened, and the premixed material reaches the saturated dissolved concentration of the gas in advance before entering the reactor (that is, the thermodynamic Metastable equilibrium state), that is, it enters the reaction preparation state in advance. Since the premixed material has already started to react or is ready to react in the lower part of the reactor, it is favorable for the direct and rapid reaction of the reactants. The premixed material in the reaction ready state enters the main reaction control unit for further reaction, which significantly improves the conversion rate and selectivity of the reaction, and is beneficial to reduce the volume of the reactor. Therefore, the above-mentioned method just effectively solves the above-mentioned technical problem.

According to a preferred technical solution of the present invention, the main process gas-phase feed and the premixed material enter upward into the reaction main control unit in the manner of plug flow for reaction.

Such setting is beneficial to the reaction efficiency, reaction conversion rate and selectivity of the gas-liquid phase reaction. For example, for an exothermic reaction, backmixing will result in an increase in the temperature of the reaction mass and a decrease in selectivity. Backmixing can be minimized by using plug flow.

In order to realize the above-mentioned way of the parallel flow, various structures in the prior art can be adopted to realize the implementation. In the present invention, the plug flow is effectively realized through a specially arranged structure.

Preferably, the reactor further comprises a gas distributor connected with the main stream gas phase feed port, and a liquid velocity distribution unit connected with the premix material feed port; wherein:

The liquid velocity distribution unit includes a unit body, the unit body is provided with a unit inlet and several liquid velocity distribution outlets, the unit inlet is connected with the premix material inlet, and the liquid velocity distribution outlet is provided There is a discharge pipe, the liquid velocity distribution outlet and the discharge pipe are respectively distributed along the cross section of the reactor; the closer the cross-sectional area of the discharge pipe to the side wall of the reactor, the greater the The cross-sectional area of the outlet pipe in the center of the reactor is smaller; and the length of the outlet pipe closer to the side wall of the reactor is shorter, and the outlet pipe closer to the center of the reactor is shorter. The longer the length; so that the flow rate of the liquid in the middle of the reactor is relatively small, and the amount of liquid is relatively small; the flow rate of the liquid close to the side wall of the reactor is relatively large, and the amount of liquid is relatively large;

The premixed material and the gas-phase feed in the main process realize an upward parallel flow above the liquid velocity distribution unit, and enter the reaction main control unit upward.

It should be noted that, in the present invention, after the main process gas phase feed injected into the bottom of the reactor passes through the gas distributor, a bubble upflow flow state is formed inside the reactor, which belongs to the flow of a conventional bubbling reactor. state characteristics, showing the liquid velocity distribution in which the side wall liquid velocity is downward and the central liquid velocity is upward. This will result in some degree of backmixing, thereby reducing reaction conversion and selectivity.

Through the above method of the present invention, the premixed material enters the liquid velocity distribution unit, which causes the premixed material to flow upward and present an initial distribution of liquid with high sidewall distribution flow rate and low center distribution flow rate. After being superimposed with the liquid velocity distribution of the downward liquid velocity of the side wall and the upward liquid velocity of the central liquid velocity under the liquid velocity distribution unit, the overall liquid velocity can be presented as a horizontal push upward flow. It is very beneficial to improve the conversion rate and selectivity of the reaction.

By the above method of the present invention, the premixed material from the hydraulic premixer enters the liquid velocity distribution unit of the reactor, the liquid velocity distribution unit causes the premixed material to flow upward and presents a high sidewall distribution flow rate , The initial distribution of the liquid with low flow velocity in the center distribution is superimposed with the liquid velocity distribution in the side wall below the liquid velocity distribution unit with the liquid velocity downward and the central liquid velocity upward, so as to present an overall flat push flow of the liquid upward. flow.

It should be noted that the main reaction control unit is usually a stirring reaction unit, a fixed bed, a fluidized bed, a packing unit and the like. Or an empty reactor, where the gas and liquid phases react on their way up the reactor.

It should be noted that the superficial gas velocity of the main process gas phase feed in the reactor affects the guarantee of the plug flow in the reactor. Therefore, under the conditions of the method of the present invention, according to the difference of the superficial gas velocity of the gas-phase feed in the main process, the reaction can be ensured as far as possible by adjusting the ratio of the maximum cross-sectional area to the minimum cross-sectional area of the discharge pipe The fluid in the device is in a state of plug flow.

Further preferably, when the superficial gas velocity of the main process gas-phase feed in the reactor is less than 5 mm/s, the ratio of the maximum cross-sectional area to the minimum cross-sectional area of the discharge pipe is not greater than 1.5;

When the superficial gas velocity of the main process gas phase feed in the reactor is 5mm/s～0.1m/s, the ratio of the maximum cross-sectional area to the minimum cross-sectional area of the discharge pipe is 1.5～0.1m/s 10;

When the superficial gas velocity of the main process gas phase feed in the reactor is greater than 0.1 m/s, the ratio of the maximum cross-sectional area to the minimum cross-sectional area of the outlet pipe is not less than 10.

The second object of the present invention is to provide a gas-liquid reaction device, comprising a hydraulic premixer and a reactor connected to the hydraulic premixer; the gas-phase feed is branched into partial gas-phase feed and the main process gas-phase Feed; per unit time, the amount of the part of the gas phase feed is 1.01 to 2 times the amount of the gas phase required to make the liquid phase feed reach the gas phase saturated dissolved concentration; wherein:

The hydraulic premixer includes a cylinder body, a liquid-phase feed port and a gas-phase feed port arranged at one end of the cylinder body, and a premix material discharge port arranged at the other end of the cylinder body; The feed is connected with the liquid-phase feed port, and the part of the gas-phase feed is connected with the gas-phase feed port; the inside of the cylinder is from the liquid-phase feed port and the gas-phase feed port to the gas-phase feed port. A larger bubble generator, several high-speed flow channels, at least one micro-bubble generator, and several low-speed flow channels are sequentially arranged in the direction of the premixed material discharge port; the ends of the micro-bubble generator and the high-speed flow channel connect;

The part of the gas-phase feed passes through the larger bubble generator and is distributed in the liquid-phase feed with larger bubbles to obtain a mixed feed containing larger bubbles; then flows through the high-speed flow channel, and passes through the The micro-bubble generator obtains a mixed feed containing micro-bubbles; finally, it flows out from the premix material discharge port after passing through the low-speed flow channel to obtain a premix material;

The lower part of the reactor is provided with a main process gas phase feed port, a premix material feed port is provided above the main process gas phase feed port, and the reactor above the premix material feed port is: The reaction main control unit is provided with a gas-phase reaction product outlet and a liquid-phase reaction product outlet; the premixed material enters the reactor from the premixed material feed port, and the main process flow The gas-phase feed enters the reactor through the gas-phase feed port of the main process, and enters the reaction main control unit together with the premixed material upward;

The liquid Reynolds number in the high-speed flow channel is 2000-200,000 to form relatively strong liquid phase turbulence conditions; the liquid Reynolds number in the low-speed flow channel is 0.1-2000 to form relatively weak liquid phase turbulence Conditions; the ratio of the residence time of the gas in the high-speed flow channel to the residence time of the gas in the low-speed flow channel is 0.01-1; the particle Reynolds number of the fine bubbles is less than 1.

It should be noted that those skilled in the art can easily understand that the arrangement of the high-speed flow channel and the low-speed flow channel is a relative concept. When the cross-sectional area of the flow channel becomes smaller, the flow rate increases. The larger the area, the lower the flow rate.

In the present invention, the total cross-sectional area of the high-speed flow channel is smaller than the cross-sectional area of the cylinder at the inlet end, so as to form a liquid-phase material flowing at a high speed.

The total cross-sectional area of the low-speed flow channels is greater than the total cross-sectional area of the high-speed flow channels, so as to form a low-speed flowing liquid phase material with a lower speed relative to the high-speed fluid in the high-speed flow channels.

In this way, the hydraulic premixer with a specific structure can effectively ensure that the gas phase in the premixed material entering the reactor reaches saturated solubility, that is, a thermodynamic metastable equilibrium state is reached, that is, the reaction preparation state is entered in advance. Thereby, the initial reaction efficiency of the premixed material in the main reaction control unit is improved, the overall reaction conversion rate and selectivity are mentioned, and the volume of the reactor is significantly reduced.

It should be noted that, in the present invention, the number of the micro-bubble generators is the flow rate of the liquid-phase feed divided by the processing capacity of a single micro-bubble generator and rounded up. Usually, at least one fine bubble generator is provided.

Preferably, the lower part of the reactor is provided with a gas distributor and a liquid velocity distribution unit in sequence from bottom to top, the main process gas phase feed enters the reactor from the main process gas phase feed port, and passes through the gas Distributor distribution; the premixed material enters the reactor from the premixed material feed port, and is distributed through the liquid velocity distribution unit;

The liquid velocity distribution unit includes a unit body, the unit body is provided with a unit inlet and several liquid velocity distribution outlets, the unit inlet is connected with the premix material inlet, and the liquid velocity distribution outlet is provided There is a discharge pipe, the liquid velocity distribution outlet and the discharge pipe are respectively distributed along the cross section of the reactor; the closer the cross-sectional area of the discharge pipe to the side wall of the reactor, the greater the The cross-sectional area of the outlet pipe in the center of the reactor is smaller; and the length of the outlet pipe closer to the side wall of the reactor is shorter, and the outlet pipe closer to the center of the reactor is shorter. The longer the length; so that the flow rate of the liquid in the middle of the reactor is relatively small, and the amount of liquid is relatively small; the flow rate of the liquid close to the side wall of the reactor is relatively large, and the amount of liquid is relatively large;

The premixed material and the gas-phase feed in the main process realize an upward parallel flow above the liquid velocity distribution unit, and enter the reaction main control unit upward.

In this way, through the liquid velocity distribution unit with a specific structure, the plug flow state of the fluid in the reactor can be effectively ensured, thereby further improving the reaction conversion rate and selectivity.

Preferably, the maximum cross-sectional area of the discharge pipe is not more than 100 square centimeters; the minimum cross-sectional area of the discharge pipe is not less than 1 square millimeter.

Those skilled in the art can easily understand that the method for generating larger air bubbles is an aeration or bubbling method based on the throttling principle. The micro-bubble generation method is a vortex, jet, venturi or impeller method based on the principle of liquid shearing.

Preferably, the larger bubble generator is a gas distributor or a porous medium bubbler;

The micro-bubble generator is selected from one or more of a venturi tube, a jet tube, and a microporous aeration unit.

According to a preferred technical solution of the present invention, the micro-bubble generator comprises a cylindrical shell, one end of the shell has a mixed material inlet, the other end has a mixed material discharge port, the mixed material inlet and the mixed material discharge A tapered nozzle, a throttling nozzle and a gradually expanding nozzle are sequentially arranged between the ports; the inside of the tapering nozzle defines a tapering cavity, the inside of the throttling nozzle defines a throttling cavity, and the inside of the gradually expanding nozzle defines a throttling cavity. A tapered cavity and an outlet cavity are defined inside, and a backmix cavity is provided between the tapered nozzle and the throttling nozzle.

Preferably, the high-speed flow channels are uniformly distributed along the circumference of the cylinder in the hydraulic premixer; the micro-bubble generator is arranged along the cylinder in the hydraulic premixer. The cross section is uniformly distributed around the circumference. The above arrangement enables the undissolved larger bubbles in the mixed material passing through the high-speed flow channel to be uniformly dispersed into fine bubbles, which is beneficial to ensure further dissolution of the gas in the subsequent process, reaching or exceeding the saturated dissolution concentration.

Preferably, the gas-liquid reaction device further includes a high-speed flow channel assembly and a low-speed flow channel assembly; the high-speed flow channel assembly includes the high-speed flow channel, and a high-speed flow channel defining component, the high-speed flow channel defining component and the high-speed flow channel defining component. The cylindrical body is fixedly connected; the low-speed flow channel assembly includes the low-speed flow channel and a low-speed flow channel limiting component, and the low-speed flow channel limiting component is fixedly connected to the cylindrical body.

It should be noted that the amount of some gaseous substances entering the hydraulic premixer should be slightly larger than the amount of substances required to be saturated and dissolved in the premixer liquid, and the slight excess of gas should be kept in the liquid phase in the form of fine bubbles. middle.

Preferably, the amount of the part of the gas-phase feed per unit time is 1.01-1.3 times the gas-phase amount required to make the liquid-phase feed reach the gas-phase saturated dissolved concentration.

Compared with the prior art, the present invention has the following beneficial technical effects:

(1), the gas-liquid reaction method of entering the reaction preparation state in advance of the present invention can not only effectively realize the continuous feeding of the reactor, but also the gas phase or liquid phase materials do not need to be circulated, which reduces the circulation cost; Part of the gas-phase feed interacts with the liquid-phase feed in advance, and the kinetic energy of the liquid-phase feed is used to pre-mix part of the gas-phase feed and the liquid-phase feed before entering the reactor, so as to dissolve the gas in the liquid at a saturated concentration in advance , enter the reaction preparation state in advance. When entering the reactor, it can participate in the reaction immediately after reaching the required pressure and temperature, so as to speed up the reaction efficiency, thereby increasing the gas content of the reactor, improving the conversion rate and selectivity of the reaction to close to the reaction equilibrium conversion rate and selectivity, It can reduce the volume of the reactor, and is very suitable for medium-speed and slow gas-liquid reactions such as oxidation, hydrogenation, chlorination, and alkylation.

(2) The gas-liquid reaction device of the present invention includes a hydraulic premixer and a reactor. Through the hydraulic premixer containing a large bubble generator, a high-speed flow channel, a micro-bubble generator and a low-speed flow channel, the residence time required for dissolving gas is greatly shortened, and the dissolved gas concentration is high, effectively realizing the The gas phase in the premixed material reaches the saturated dissolved concentration, that is, it enters the reaction preparation stage in advance, which is beneficial to the reaction efficiency, thereby increasing the gas content of the reactor, improving the conversion rate and selectivity of the reaction to close to the reaction equilibrium conversion rate and selectivity, and The reactor volume can be reduced.

Description of drawings

FIG. 1 is a flow chart of the gas-liquid reaction apparatus of Example 1. FIG.

FIG. 2 is a schematic longitudinal section view of the structure of the hydraulic premixer.

FIG. 3 is a schematic diagram of the structure of a hydraulic premixer and a longitudinal cross-sectional diagram (the high-speed flow channel assembly is a tubular structure).

FIG. 4 is a schematic longitudinal cross-sectional schematic diagram of the structure of the micro-bubble generator.

FIG. 5 is a flow chart of the gas-liquid reaction device of Example 2. FIG.

Figure 6 is a flow diagram of a conventional bubble reactor setup.

Detailed ways

The present invention will be further described below with reference to specific embodiments. It should be understood that the following examples are only used to illustrate the present invention and not to limit the scope of the present invention.

Embodiment 1, a kind of gas-liquid reaction device

As shown in FIGS. 1 to 4 , this embodiment provides a gas-liquid reaction device, including a hydraulic premixer 10 and a reactor 20 connected to the hydraulic premixer 10 ; the gas-phase feed branch V is Part of the gas-phase feed V1 and the main process gas-phase feed V2; the amount of the partial gas-phase feed V1 per unit time is 1.01 to 2 times the gas-phase amount required to make the liquid-phase feed L reach the gas-phase saturated dissolved concentration . in:

The hydraulic premixer 10 includes a cylinder body 11 , a liquid phase feed port 12 and a gas phase feed port 13 arranged at one end of the cylinder body 11 , and a premix material arranged at the other end of the cylinder body 11 . The discharge port 14; the liquid phase feed L is connected with the liquid phase feed port 12, and the part of the gas phase feed V1 is connected with the gas phase feed port 13; the inside of the cylinder 11 is connected from the The direction from the liquid phase feed port 12 and the gas phase feed port 13 to the premixed material discharge port 14 is sequentially provided with a larger bubble generator 15, a number of high-speed flow channels 16, a number of fine bubble generators 17, and A plurality of low-speed flow channels 18; the micro-bubble generator 17 is connected to the end of the high-speed flow channel 16, and the end of each of the high-speed flow channels 16 is respectively connected to one of the micro-bubble generators 17.

The part of the gas phase feed V1 passes through the larger bubble generator 15 and is distributed in the liquid phase feed L with larger bubbles to obtain a mixed feed containing larger bubbles; then flows through the high-speed flow channel 16, and through the micro-bubble generator 17 to obtain a mixed feed containing micro-bubbles; finally, the low-speed flow channel 17 flows out from the premix material outlet 14 to obtain a premix material.

The lower part of the reactor 20 is provided with a main process gas phase feed port 21, a premix material feed port 22 is provided above the main process gas phase feed port 21, and a premix material feed port 22 is provided above the premix material feed port 22. The reactor 20 is a reaction main control unit 23, and the reaction main control unit 23 is provided with a gas-phase reaction product outlet 24 and a liquid-phase reaction product outlet 27; the premixed material is fed from the premixed material inlet 22. Entering into the reactor 20, the main process gas phase feed V2 enters the reactor 20 through the main process gas phase feed port 21, and enters the reaction main control unit together with the premixed material upward within 23.

The liquid Reynolds number in the high-speed flow channel 16 is 2000-200000 to form a relatively strong liquid phase turbulence condition; the liquid Reynolds number in the low-speed flow channel 18 is 0.1-2000 to form a relatively weak liquid Reynolds number. Liquid phase turbulent conditions; the ratio of the residence time of the gas in the high-speed flow channel 16 to the residence time of the gas in the low-speed flow channel is 0.01-1.

It should be noted that, in this embodiment, the residence time of the gas in the high-speed flow channel 16 is 1 to 3 seconds.

小于1的气泡认为是微细气泡，即所述微细气泡的颗粒雷诺数小于1。较大气泡的颗粒雷诺数大于等于1。In fact, the gas-liquid physical properties under actual working conditions are very different from the daily air-water system, and the larger bubbles and fine bubbles are only the difference in relative size. Preferably, in the present invention, the particle Reynolds number

The bubbles less than 1 are considered to be fine bubbles, that is, the particle Reynolds number of the fine bubbles is less than 1. The particle Reynolds number of larger bubbles is greater than or equal to 1.

It should be noted that, under the conditions of the present invention, since most of the gas in the high-speed flow channel is large bubbles, and almost all of the gas in the low-speed flow channel is fine bubbles, the residence time of the larger bubbles The residence time of the fine bubbles is equivalent to the residence time of the gas in the high-speed flow channel, and the residence time of the fine bubbles is equivalent to the residence time of the gas in the low-speed flow channel. That is, the ratio of the residence time of the larger bubbles in the high-speed flow channel to the residence time of the fine bubbles in the low-speed flow channel is 0.01-1.

It should be noted that the part before the high-speed flow channel 16 in the hydraulic premixer 10 includes a liquid inlet section, and the larger bubble generator is arranged in the liquid inlet section. The part after the low-speed flow channel 18 includes the liquid outlet section. The lengths of the liquid inlet section and the liquid outlet section can be set according to actual needs, as long as the residence time of the gas in the high-speed flow channel and the low-speed flow channel satisfies the above range. Therefore, those skilled in the art can easily understand that the total gas residence time in the hydraulic premixer 10 varies with the lengths of the liquid inlet section and the liquid outlet section and the length of the micro-bubble generator.

Typically, the lengths of the liquid inlet section and the liquid outlet section are short relative to the lengths of the high-speed flow channels 16 and the low-speed flow channels 18 . The liquid inlet section and the liquid outlet section are usually shortened as much as possible on the premise that the concentration of the gas phase in the premixed material can all reach the saturated dissolved concentration, so as to reduce the cost.

The gas-liquid reaction device of the present embodiment is used as follows:

(1) All the liquid phase feed L enters the hydraulic premixer 10 through the liquid phase feed port 12 , and part of the gas phase feed V1 enters the liquid phase feed port 13 A hydraulic premixer 10, and a mixed feed containing larger bubbles is formed in the hydraulic premixer 10 through the larger bubble generator 15;

(2), then make the mixed feed containing larger bubbles pass through several horizontally arranged high-speed flow channels 16, so that the larger bubbles in the mixed feed containing larger bubbles are quickly dissolved into the liquid phase , to obtain a mixed feed with a large amount of dissolved gas;

(3), then make the mixed feed with a larger amount of dissolved gas flow into the micro-bubble generator 17, and form a mixed feed containing micro-bubbles under high shear;

(4), then make the mixed feed containing fine bubbles pass through several low-speed flow channels 18 set horizontally, and obtain good dissolution in the low-speed flow channels 18 to reach a saturated dissolved concentration, complete pre-mixing, and obtain a pre-mixture. mixed material.

(5), then the premixed material comes out from the premixed material discharge port 14 of the hydraulic premixer 10, and then passes through the feeding pipeline and is fed from the premixed material connected to the end of the feeding pipeline The port 22 enters the reactor 20, and the main process gas phase feed V2 enters the bottom of the reactor 20 through the main process gas phase feed port 21, and enters the reaction main control unit with the premixed material upward. 23. After the catalytic reaction, the obtained gas and liquid phase reaction products flow out from the gas phase reaction product outlet 24 and the liquid phase reaction product outlet 27.

After testing, the concentration of the gas phase in the premixed material can all reach the saturated dissolved concentration.

It should be noted that those skilled in the art can easily understand that the arrangement of the high-speed flow channel 16 and the low-speed flow channel 18 is a relative concept. When the cross-sectional area of the flow channel becomes smaller, the flow velocity increases. The larger the cross-sectional area, the lower the flow velocity.

In the present invention, the total cross-sectional area of the high-speed flow channel 16 is smaller than the cross-sectional area of the cylinder at the inlet end, so as to form a relatively strong liquid phase turbulence condition. The total cross-sectional area of the low-speed flow channel 18 is larger than the total cross-sectional area of the high-speed flow channel, so as to form a relatively weak liquid phase turbulence condition, thereby forming a relatively low velocity relative to the high-speed fluid in the high-speed flow channel. Mixed materials with low low velocity flow.

In this way, the hydraulic premixer provided with the above-mentioned specific structure can effectively ensure that the gas phase in the premixed material entering the reactor reaches the saturated dissolved concentration, that is, a thermodynamic metastable equilibrium state is reached, that is, the reaction preparation is entered in advance. state.

Of course, those skilled in the art can also set up a hydraulic premixer of other structures, as long as it can ensure that the gas phase in the premixed material entering the reactor reaches a saturated dissolved concentration.

According to some preferred embodiments of the present invention, the device further includes a high-speed flow channel assembly and a low-speed flow channel assembly; the high-speed flow channel assembly includes the high-speed flow channel 16, and a high-speed flow channel defining part 161, the high-speed flow channel The limiting member 161 is fixedly connected with the cylindrical body 11 ; the low-speed flow channel assembly includes the low-speed flow channel 18 and a low-speed flow channel limiting member 181 , and the low-speed flow channel limiting member is fixedly connected with the cylindrical body 11 .

The high-speed flow channel-defining member may be in various forms in the prior art. A specific form can be as follows: it includes a cylindrical part installed in the cylinder, the outer wall of the cylindrical part is fixed with clearance fit with the inner wall of the cylinder, and the interior of the cylindrical part is distributed with several levels. set vias. Since the liquid-phase feed on the side of the inlet end of the cylindrical member is forced to flow toward the side of the outlet end of the cylindrical member along the through-holes with smaller cross-sections, the liquid-phase feed in the through-holes The flow velocity is significantly increased, thereby forming a high-speed flow channel.

Of course, those skilled in the art can easily understand that other forms of components in the prior art can also be used to form the high-speed flow channel, as shown in FIG. 3 , for example, including a circular left baffle 162 and a right baffle Plate 163, the outer walls of the left baffle 162 and the right baffle 163 are fixedly connected to the inner wall of the cylinder, the left baffle 162 and the right baffle 163 are correspondingly provided with a number of openings, the openings are respectively The high-speed flow channel 16 is formed in the inside of the tube 164 through the connection.

The low-speed flow channel defining member 181 may be in various forms in the prior art. A specific form may be: including cylindrical structures annularly distributed along the inner wall of the cylindrical body 11 , the outer wall of the cylindrical structure is fixedly connected with the inner wall of the cylindrical body 11 , and the interior of the cylindrical structure has For a Venturi-type channel, the cross-sectional area of the throat of the channel is greater than the total cross-sectional area of the high-speed flow channel. Therefore, the flow velocity of the fluid in the venturi-shaped channel is smaller than the flow velocity of the fluid in the high-speed flow channel, thus forming the low-speed flow channel. The low-speed flow channel may be one or multiple.

Of course, those skilled in the art can easily understand that other forms of components in the prior art may also be used for the formation of the low-speed flow channel.

It should be noted that, of course, as shown in FIG. 3 , a micro-bubble generator mounting plate 1712 can be provided at the end of the high-speed flow channel 16 , and the outer periphery of the micro-bubble generator mounting plate 1712 is connected to the inner wall of the cylinder. Fixed connection between them and sealed to form a channel. The mixed material flowing out of the high-speed flow channel 16 enters the cavity between the end of the high-speed flow channel and the micro-bubble generator mounting plate 1712 . The micro-bubble generator mounting plate 1712 defines a plurality of openings, and the micro-bubble generators 17 are correspondingly installed on the openings. The number of the micro-bubble generators 17 is the flow rate of the liquid phase feed divided by the processing capacity of a single micro-bubble generator and rounded up. Usually, at least one fine bubble generator is provided.

Those skilled in the art can easily understand that the method for generating larger air bubbles is an aeration or bubbling method based on the throttling principle. The micro-bubble generation method is a vortex, jet, venturi or impeller method based on the principle of liquid shearing.

Preferably, the larger bubble generator is a gas distributor or a porous media bubbler. According to some preferred embodiments of the present invention, the larger bubble generator 15 is a ring tube with several openings, the diameter of the openings on the ring tube is 1-5 mm, and the bending radius R of the ring tube is about It is 1/4 of the inner diameter D of the hydraulic premixer.

The micro-bubble generator is selected from one or more of a venturi tube, a jet tube, and a microporous aeration unit.

As shown in FIG. 4 , the micro-bubble generator 17 in this embodiment 1 includes a cylindrical casing 171 , one end of the casing 171 has a mixed material inlet 172 , and the other end has a mixed material outlet 173 . Between the material inlet 172 and the mixed material discharge port 173, a tapered nozzle 174, a throttling nozzle 175 and a gradually expanding nozzle 176 are arranged in sequence; the inside of the tapering nozzle 174 defines a tapering cavity 177, the throttling nozzle 177 The inside of 175 defines a throttle cavity 178 , the inside of the expanding nozzle 176 defines a expanding cavity 179 and an outlet cavity 1710 , and there is a back-mixing cavity 1711 between the narrowing nozzle 174 and the throttle nozzle 175 .

Since the micro-bubble generator has a special structure of taper-throttle-expansion, the high-flow mixed material flowing out of the high-speed flow channel enters the micro-bubble generator from the mixed material inlet, and then passes through the taper When the nozzle is used, the highly turbulent liquid phase provides the energy for bubble breakage, and further gas-liquid circulation agitation occurs in the backmixing chamber, so the bubbles are broken into countless fine bubbles in the backmixing chamber, and the The expanding cavity and the outlet cavity of the gradually expanding nozzle are uniformly dispersed in the liquid phase, and finally flow out from the discharge port of the mixed material to form a mixed material containing fine bubbles.

The relevant dimensions of the micro-bubble generator are shown in Table 1.

Table 1. Relevant dimensions of the micro-bubble generator

size size name Design range d₀ Mixed material inlet diameter 4～40mm d₁ Tapered Nozzle Outlet Diameter (0.4～0.7)d₀ d₂ The diameter of the throttle chamber of the throttle nozzle (0.3～0.5)d₁ d₃ Outlet diameter of expanding nozzle (0.8～1.2)d₀ L₁ Overall length of housing 200～800mm L₂ Length of the throttle chamber min(20mm,3×d₂)

Preferably, the back-mixing chamber 1711 is symmetrically located between the outer wall of the tapered nozzle 174 and the casing 171 to provide a better back-mixing effect, thereby facilitating the formation of fine air bubbles.

According to some preferred embodiments of the present invention, the high-speed flow channels 16 are distributed in a circular array along the cross-section of the cylinder body 11 in the hydraulic premixer 10 . The micro-bubble generators 17 are distributed in a circular array along the cross-section of the cylinder body 11 in the hydraulic premixer 10 .

The above arrangement enables the undissolved larger bubbles in the mixed material passing through the high-speed flow channel 16 to be uniformly dispersed into fine bubbles, which is beneficial to ensure the further dissolution of the gas in the subsequent process, reaching or exceeding the saturation concentration.

It should be noted that the amount of some gaseous substances entering the hydraulic premixer 10 should be greater than the amount of substances required to be saturated and dissolved in the liquid of the premixer, and a slight excess of gas remains in the liquid in the form of fine bubbles. In phase.

Further preferably, the amount of part of the gaseous substances entering the hydraulic premixer 10 should be slightly larger than the amount of substances required for saturated dissolution in the premixer liquid. In a unit time, the amount of the part of the gas phase feed is 1.01-1.3 times the gas phase amount required to make the liquid phase feed reach the gas phase saturated dissolved concentration.

Embodiment 2, a kind of gas-liquid reaction device

As shown in FIG. 5 , the basic structure of this embodiment is the same as that of Embodiment 1, and the differences are:

The lower part of the reactor 20 is sequentially provided with a gas distributor 25 and a liquid velocity distribution unit 26 from bottom to top, and the main process gas phase feed V2 enters the reactor 20 from the main process gas phase feed port 21, and passes through the main process gas phase feed port 21. The gas distributor distributes 25 ; the premixed material enters the reactor 20 from the premixed material feed port 22 and is distributed through the liquid velocity distribution unit 26 .

The liquid velocity distribution unit 26 includes a unit body 262. The unit main body 262 is provided with a unit inlet and several liquid velocity distribution outlets. The unit inlet is connected to the premix material inlet 22. The distribution outlet is provided with a discharge pipe 261, and the liquid velocity distribution outlet and the discharge pipe 261 are respectively distributed along the cross section of the reactor; the cross-sectional area of the discharge pipe closer to the side wall of the reactor 20 The larger the size, the smaller the cross-sectional area of the outlet pipe near the center of the reactor 20; and the shorter the length of the outlet pipe closer to the side wall of the reactor 20, the closer to the reaction The longer the length of the discharge pipe 261 in the center of the reactor 20; so that the flow rate of the liquid in the middle of the reactor 20 is relatively small, and the amount of liquid is relatively small; the flow rate of the liquid close to the side wall of the reactor 20 is relatively small; Relatively large, the amount of liquid is relatively large;

The maximum cross-sectional area of the discharge pipe 261 is not more than 100 square centimeters; the minimum cross-sectional area of the discharge pipe 261 is not less than 1 square millimeter;

The premixed material and the main process gas-phase feed V1 realize an upward parallel flow above the liquid velocity distribution unit 26 and enter the reaction main control unit 23 upward.

The gas-liquid reaction device of the present embodiment is used as follows:

(1) All the liquid phase feed L enters the hydraulic premixer 10 through the liquid phase feed port 12 , and part of the gas phase feed V1 enters the liquid phase feed port 13 A hydraulic premixer 10, and a mixed feed containing larger bubbles is formed in the hydraulic premixer 10 through the larger bubble generator 15;

(2), then make the mixed feed containing larger bubbles pass through several horizontally arranged high-speed flow channels 16, so that the larger bubbles in the mixed feed containing larger bubbles are quickly dissolved into the liquid phase , to obtain a mixed feed with a large amount of dissolved gas;

(3), then make the mixed feed with a larger amount of dissolved gas flow into the micro-bubble generator 17, and form a mixed feed containing micro-bubbles under high shear;

(4), then make the mixed feed containing fine bubbles pass through several low-speed flow channels 18 set horizontally, and obtain good dissolution in the low-speed flow channels 18 to reach saturated dissolution concentration, complete pre-mixing, and obtain pre-mixing. mixed material.

(5), then the premixed material comes out from the premixed material discharge port 14 of the hydraulic premixer 10, and then passes through the feeding pipeline and is fed from the premixed material connected to the end of the feeding pipeline The port 22 enters the reactor 20 and is distributed through the liquid velocity distribution unit 26; the main process gas phase feed V2 enters the bottom of the reactor 20 through the main process gas phase feed port 21 The gas distributor 25 and the premixed material realize upward parallel flow above the liquid velocity distribution unit 26, and enter the reaction main control unit 23. After catalytic reaction, the obtained gas and liquid phase reaction products are obtained from the The gas phase reaction product outlet 24 and the liquid phase reaction product outlet 27 flow out.

After testing, the concentration of the gas phase in the premixed material can all reach the saturated dissolved concentration.

It should be noted that those skilled in the art can easily understand the specific structure of the above-mentioned liquid velocity distribution unit 26. For example, the liquid velocity distribution unit 26 may be a liquid distributor, and may be a serpentine concentric ring pipe. A plurality of the liquid velocity distribution outlets with different cross-sectional areas are opened on the concentric annular pipes, and the discharge pipes 261 with different cross-sectional areas are inserted into the liquid velocity distribution outlets.

Embodiment 3, effect detection

The devices of Example 1 and Example 2 and the traditional bubble reactor device were used for comparative experiments respectively. The reaction flow of a conventional bubbling reactor is shown in Figure 6.

(1), carry out autocatalytic oxidation reaction - cumene is oxidized to cumene hydrogen peroxide. The process and parameters are as follows:

Oxidation of cumene to cumene hydrogen peroxide reaction conditions: the reaction temperature is 110°C, the reaction pressure is 0.6MPa, and the gas-liquid ratio is 9:1.

A plexiglass cylinder with an inner diameter of 180 mm and a height of 2000 mm was used as a reactor for testing. The reaction main control unit 23 is an empty cylinder, and no filler or catalyst layer is provided.

The inner diameter D of the cylinder of the hydraulic premixer 10 is 50 mm, the total length is 2000 mm, there are 10 high-speed flow channels, and the inner diameter of each high-speed flow channel is 6 mm.

In the micro-bubble generator 17, the inlet diameter d ₀ of the mixture material is 5 mm, the outlet diameter d ₁ of the tapered nozzle is 2.5 mm, the throttling cavity diameter d ₂ of the throttle nozzle is 1.2 mm, and the gradually expanding nozzle is 1.2 mm. The outlet mouth diameter _d3 is 6mm. The overall length L ₁ of the housing is 400mm, and the length L ₂ of the throttle chamber is 3.6mm.

The amount of the part of the gas-phase feed per unit time is 1.2 times the gas-phase amount required to make the liquid-phase feed reach the gas-phase saturated dissolved concentration.

Under the conditions of the three experimental devices, the gas flow and liquid flow into the reactor were kept the same, and the liquid residence time in the reactor was ensured for 5 hours.

In Example 2, the inner ring of the liquid velocity distribution unit 26 is evenly distributed with 4 liquid outlet pipes 261, the outer ring is evenly distributed with 8 liquid outlet pipes 261, and the outer ring of the liquid outlet pipes 261 is arranged horizontally. The cross-sectional area is 0.5 square centimeters, and the cross-sectional area of the liquid outlet pipe 261 of the inner ring is 0.083 square centimeters. The ratio of the cross-sectional area of the liquid outlet pipe 261 of the outer ring to the cross-sectional area of the liquid outlet pipe 261 of the inner ring is 6.

The liquid Reynolds number in the high-speed flow channel 16 in the hydraulic premixer 10 is 4,000, the liquid Reynolds number in the low-speed flow channel 18 is 1,000, and the gas residence time in the high-speed flow channel 16 is the same as the above. The ratio of the gas residence time in the low-speed flow channel 18 is 0.1; the particle Reynolds number of the fine bubbles is 0.2. The gas residence time in the high-speed flow channel 16 is 1.5 seconds.

In the examples 1 and 2, the superficial gas velocity of the main process gas-phase feed V2 in the reactor 20 is controlled to be 0.05 m/s. In the bubbling reactor device, the superficial gas velocity of the gas-phase feed in the reactor 20 is controlled to be 0.05 m/s. After testing, the concentration of the gas phase in the premixed material reaches the saturated dissolved concentration.

The results are shown in Table 2.

Table 2, cumene oxidation is the reaction main control unit parameter value comparison in hydrogen peroxide cumene

In this embodiment, the definition of gas content: the percentage of the gas phase in the reactor to the total volume of the reactor. Total gas phase inlet: the total amount of gas phase entering the reactor.

It can be seen from the data in Table 2 that the selectivity of Example 1 and Example 2 are respectively increased by 7.5% and 15% compared with the conversion rate of the bubbling reactor device, the selectivity is increased by 3.3% and 6.5%, and the gas content is increased by 3.3% and 6.5%, respectively. Increased by 200% and 300%.

(2), change the relevant parameters to test the effect

(1), other conditions are the same as (1), the difference is:

The amount of the part of the gas-phase feed per unit time is 1.01 times the gas-phase amount required to make the liquid-phase feed reach the gas-phase saturated dissolved concentration.

The liquid Reynolds number in the high-speed flow channel 16 in the hydraulic premixer 10 is controlled to be 2000, the liquid Reynolds number in the low-speed flow channel 18 is 0.1, and the gas residence time in the high-speed flow channel 16 is equal to The ratio of the gas residence time in the low-speed flow channel 18 is 0.01, and the particle Reynolds number of the fine bubbles is 0.15. The gas residence time in the high-speed flow channel 16 is 1.5 seconds.

The results are shown in Table 3.

Table 3, cumene oxidation is the reaction main control unit parameter value comparison in hydrogen peroxide cumene

From the data in Table 3, it can be seen that the selectivity of Example 1 and Example 2 are respectively increased by 7.7% and 12.8% compared to the conversion rate of the bubbling reactor device, the selectivity is increased by 3.2% and 4.3%, and the gas content is increased by 3.2% and 4.3%, respectively. improved by 205% and 281%.

(2), other conditions are the same as (1), the difference is:

In a unit time, the amount of the part of the gas phase feed is twice the amount of the gas phase required to make the liquid phase feed reach the saturated dissolved concentration in the gas phase.

The liquid Reynolds number in the high-speed flow channel 16 in the hydraulic premixer 10 is controlled to be 200,000, the liquid Reynolds number in the low-speed flow channel 18 is 2000, and the gas residence time in the high-speed flow channel 16 is equal to The ratio of the gas residence time in the low-speed flow channel 18 is 1, and the particle Reynolds number of the fine bubbles is 0.8. The gas residence time in the high-speed flow channel 16 is 1.5 seconds.

The results are shown in Table 4.

Table 4, cumene oxidation is the reaction main control unit parameter value comparison in hydrogen peroxide cumene

From the data in Table 4, it can be seen that the selectivity of Example 1 and Example 2 are respectively increased by 15% and 25% compared with the conversion rate of the bubbling reactor device, the selectivity is increased by 3.3% and 5.5%, and the gas content is increased by 3.3% and 5.5%, respectively. 183% and 275% higher.

It can be seen from the data in Tables 2 to 4 that, under the condition that the total gas inlet amount of the gas phase is equivalent, compared with the conventional bubbling reactor device, the gas content of the device of Example 1 and Example 2 is higher than that of the bubbling reactor device. On the basis of the increase of 183% to 300%. It can be seen that, under the conditions of the devices of Example 1 and Example 2 and the reaction parameters of the present invention, the gas content in the reactor is greatly improved. Therefore, under the premise of achieving the same gas content, the flow rate of the required main process gas can be greatly reduced, thereby reducing the gas-liquid ratio, and also reducing the energy consumption of the gas compressor required to transport the gas. According to theoretical calculations, the gas-liquid ratio can be reduced to (3-4):1.

It is well known to those skilled in the art that in the reaction of cumene oxidation to cumene hydroperoxide, the upper limit of the conversion rate is about 25%, and the upper limit of the selectivity is about 98-99% according to the conversion equilibrium calculation. And the closer it is to the upper limit, the more difficult it is to improve. Compared with the conventional bubbling reactor device, the conversion rate of the devices of Example 1 and Example 2 is increased by 7.5% to 25%, and the selectivity is increased by 3.2% to 6.5%. By using the device and method of the present invention, the conversion rate can be further increased to 21-25% on the basis of the traditional bubbling reactor device, which is already very close to the upper limit of the conversion rate; the selectivity can be further increased to 94-98%, which is already very high. Approaching the conversion rate limit. Under the conditions of achieving the same conversion rate and selectivity, the device and method of the present invention can effectively reduce the volume of the reactor. Therefore, by adopting the device and method of the present invention, the conversion rate and selectivity can be effectively improved, and it is of great significance to improve the product purity and the utilization rate of raw materials.

To sum up, within the scope of the device and reaction parameters of the present invention, the beneficial technical effects of the present invention can be achieved. The gas-liquid reaction method and the corresponding device of the present invention can effectively realize that the gas phase in the premixed material reaches the saturated dissolved concentration, that is, the reaction preparation stage is entered in advance, which is beneficial to the reaction efficiency, thereby improving the gas content of the reactor and the conversion of the reaction. efficiency and selectivity, and reduce reactor volume.

(3), the apparent gas velocity of the main process gas phase feed in the reactor

On the basis of the above Example 2, in order to achieve the effect of the plug flow in the reactor as much as possible, the apparent gas velocity of the main process gas phase feed in the reactor is now changed, and the experimental device is obtained. The range of the ratio of the maximum cross-sectional area to the minimum cross-sectional area of the discharge pipe of the liquid velocity distribution unit under the conditions is as follows:

When the superficial gas velocity of the main process gas phase feed in the reactor is less than 5 mm/s, preferably the ratio of the maximum cross-sectional area to the minimum cross-sectional area of the outlet pipe of the liquid velocity distribution unit is not greater than 1.5. At this time, the apparent gas velocity is very low, which belongs to the quiet bubbling state.

When the superficial gas velocity of the main process gas phase feed in the reactor is in the range of 5 mm/s to 0.1 m/s, it is preferable that the maximum cross-sectional area and the minimum cross-sectional area of the discharge pipe 261 of the liquid velocity distribution unit are The ratio of the cross-sectional area is 1.5 to 10. At this time, the apparent gas velocity is moderate, which is a good plug flow state.

When the superficial gas velocity of the main process gas phase feed in the reactor is greater than 0.1 m/s, preferably the ratio of the maximum cross-sectional area to the minimum cross-sectional area of the outlet pipe of the liquid velocity distribution unit is not equal to less than 10. At this time, the apparent gas velocity is large and the turbulence is large, which is an approximate plug flow state.

Compared with the test data of Example 2 in Table 2, under the above conditions, good gas content can be achieved, and the conversion rate can reach 21-25%, and the selectivity can reach 94-98%.

To sum up, in the present invention, using the hydraulic premixer for gas-liquid premixing requires two steps. First, larger bubbles with uniform larger scales are generated and strong liquid phase turbulence is provided, and the strong liquid phase turbulence is used for rapid dissolution before moving away from the metastable equilibrium state. Then, when the metastable equilibrium state is approached, fine bubbles with uniform and fine scales are generated, and then a weaker liquid phase turbulence is provided, and finally the metastable equilibrium state in the flow process is reached, and the obtained premixed material reaches or exceeds the saturation of the gas phase. concentration, and entered the reaction preparation state in advance.

The specific embodiments of the present invention have been described above in detail, but they are only used as examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions made to this utility are also within the scope of the present invention. Therefore, equivalent changes and modifications made without departing from the spirit and scope of the present invention should be included within the scope of the present invention.

Claims (11)

1. The gas-liquid reaction method for entering a reaction preparation state in advance is characterized in that gas-phase feeding branches are partial gas-phase feeding and main process gas-phase feeding, a main process gas-phase feeding hole is formed in the lower portion of a reactor, a premixed material feeding hole is formed above the main process gas-phase feeding hole, and the reactor above the premixed material feeding hole is a reaction main control unit; the method comprises the following steps:

(1) forming larger bubbles in the liquid-phase feeding material by the partial gas-phase feeding material to obtain mixed feeding material containing the larger bubbles;

(2) forming a relatively strong liquid phase turbulence on the mixed feed containing the larger bubbles so as to rapidly dissolve the larger bubbles in the mixed feed containing the larger bubbles into a liquid phase to obtain a mixed feed with a large gas dissolving amount;

(3) forming the undissolved large bubbles in the mixed feed with a large gas dissolving amount into micro bubbles under a high shearing condition to obtain the mixed feed containing the micro bubbles;

(4) forming a relatively weak liquid phase turbulence in the mixed feed containing the micro-bubbles so as to further dissolve the micro-bubbles into the liquid phase feed to obtain the premix material;

(5) enabling the premixed material to enter the reactor through the premixed material feeding hole, enabling the main process gas phase feeding to enter the reactor through the main process gas phase feeding hole, and enabling the premixed material and the premixed material to enter the reaction main control unit to react upwards;

under the relatively strong liquid phase turbulence condition, the Reynolds number of the liquid is 2000-200000;

under the relatively weak liquid phase turbulence condition, the Reynolds number of the liquid is 0.1-2000;

the particle Reynolds number of the micro-bubbles is less than 1;

the amount of the partial gas phase feed is 1.01 to 2 times of the amount of the gas phase required for the liquid phase feed to reach the gas phase saturated dissolution concentration per unit time.

2. The gas-liquid reaction method for entering the reaction preparation state in advance as recited in claim 1, wherein the main process gas phase feed and the premixed material enter the reaction main control unit together in a plug flow manner to react.

3. The gas-liquid reaction method of entering into the reaction preparation state in advance as set forth in claim 2, wherein the reactor further comprises a gas distributor connected to the main stream gas phase feed port, and a liquid velocity distribution unit connected to the premixed material feed port; wherein:

the liquid velocity distribution unit comprises a unit body, a unit inlet and a plurality of liquid velocity distribution outlets are formed in the unit body, the unit inlet is connected with the premixed material feeding port, discharging pipes are arranged on the liquid velocity distribution outlets, and the liquid velocity distribution outlets and the discharging pipes are respectively distributed along the cross section of the reactor; the cross-sectional area of the tapping pipe is larger closer to the side wall of the reactor, and the cross-sectional area of the tapping pipe is smaller closer to the center of the reactor; and the shorter the length of the tapping pipe closer to the side wall of the reactor, the longer the length of the tapping pipe closer to the center of the reactor; so that the flow rate of the liquid in the middle of the reactor is relatively small and the amount of the liquid is relatively small; the flow rate of the liquid close to the side wall of the reactor is relatively large, and the amount of the liquid is relatively large;

and the premixed material and the gas-phase feeding of the main process realize upward horizontal pushing flow above the liquid velocity distribution unit and upwards enter the reaction main control unit.

4. The gas-liquid reaction method of bringing into reaction readiness in advance as set forth in claim 3, wherein when the superficial gas velocity of the main process gas phase feed in the reactor is less than 5mm/s, the ratio of the maximum cross-sectional area to the minimum cross-sectional area of the tapping pipe is not more than 1.5;

when the superficial gas velocity of the main process gas-phase feeding in the reactor is 5 mm/s-0.1 m/s, the ratio of the maximum cross-sectional area to the minimum cross-sectional area of the discharge pipe is 1.5-10;

when the superficial gas velocity of the main process gas-phase feed in the reactor is greater than 0.1m/s, the ratio of the maximum cross-sectional area to the minimum cross-sectional area of the tapping pipe is not less than 10.

5. The gas-liquid reaction device is characterized by comprising a hydraulic premixer and a reactor connected with the hydraulic premixer; the gas phase feeding branch is divided into partial gas phase feeding and main process gas phase feeding; in unit time, the amount of the partial gas phase feed is 1.01-2 times of the amount of the gas phase required for enabling the liquid phase feed to reach the gas phase saturated dissolution concentration; wherein:

the hydraulic premixer comprises a cylinder body, a liquid-phase feed inlet and a gas-phase feed inlet which are arranged at one end of the cylinder body, and a premixed material discharge outlet which is arranged at the other end of the cylinder body; the liquid phase feeding is connected with the liquid phase feeding hole, and the partial gas phase feeding is connected with the gas phase feeding hole; a large bubble generator, a plurality of high-speed flow channels, at least one micro-bubble generator and a plurality of low-speed flow channels are sequentially arranged in the cylinder body from the liquid-phase feed inlet and the gas-phase feed inlet to the premixed material discharge outlet;

the part of the gas-phase feed passes through the larger bubble generator and is distributed in the liquid-phase feed in the form of larger bubbles, so as to obtain a mixed feed containing the larger bubbles; then flows through the high-speed flow passage and passes through the micro-bubble generator to obtain mixed feeding containing micro-bubbles; finally, the mixture flows out of the premixed material discharge port after passing through the low-speed flow channel to obtain a premixed material;

the lower part of the reactor is provided with a main process gas-phase feed inlet, a premixed material feed inlet is arranged above the main process gas-phase feed inlet, the reactor above the premixed material feed inlet is a reaction main control unit, and a gas-phase reaction product outlet and a liquid-phase reaction product outlet are arranged on the reaction main control unit; the premixed material enters the reactor from the premixed material feed inlet, the main process gas-phase feed enters the reactor through the main process gas-phase feed inlet, and the premixed material and the main process gas-phase feed enter the reaction main control unit together;

the Reynolds number of the liquid in the high-speed flow channel is 2000-200000, so that a relatively strong liquid phase turbulent motion condition is formed; the Reynolds number of the liquid in the low-speed flow channel is 0.1-2000, so that a relatively weak liquid phase turbulent condition is formed; the ratio of the residence time of the gas in the high-speed flow channel to the residence time of the gas in the low-speed flow channel is 0.01-1; the particle Reynolds number of the fine bubbles is less than 1.

6. The gas-liquid reaction device according to claim 5, wherein a gas distributor and a liquid velocity distribution unit are sequentially arranged at the lower part of the reactor from bottom to top, and the main process gas phase feed enters the reactor from the main process gas phase feed inlet and is distributed by the gas distributor; the premixed material enters the reactor from the premixed material feeding hole and is distributed by the liquid velocity distribution unit;

the liquid velocity distribution unit comprises a unit body, a unit inlet and a plurality of liquid velocity distribution outlets are formed in the unit body, the unit inlet is connected with the premixed material feeding port, discharging pipes are arranged on the liquid velocity distribution outlets, and the liquid velocity distribution outlets and the discharging pipes are respectively distributed along the cross section of the reactor; the cross-sectional area of the tapping pipe is larger closer to the side wall of the reactor, and the cross-sectional area of the tapping pipe is smaller closer to the center of the reactor; and the shorter the length of the tapping pipe closer to the side wall of the reactor, the longer the length of the tapping pipe closer to the center of the reactor; so that the flow rate of the liquid in the middle of the reactor is relatively small and the amount of the liquid is relatively small; the flow rate of the liquid close to the side wall of the reactor is relatively large, and the amount of the liquid is relatively large;

and the premixed material and the gas-phase feeding of the main process realize upward horizontal pushing flow above the liquid velocity distribution unit and upwards enter the reaction main control unit.

7. The gas-liquid reaction device as recited in claim 5, wherein the larger bubble generator is a gas distributor or a porous medium bubbler; the micro-bubble generator is selected from one or more of a venturi tube, a jet pipe and a micropore aeration unit.

8. The gas-liquid reaction device according to claim 7, wherein the micro-bubble generator comprises a cylindrical housing, one end of the housing is provided with a mixed material inlet, the other end of the housing is provided with a mixed material outlet, and a convergent nozzle, a throttle nozzle and a divergent nozzle are sequentially arranged between the mixed material inlet and the mixed material outlet; the convergent nozzle has an interior defining a convergent chamber, the throttle nozzle has an interior defining a throttle chamber, the divergent nozzle has an interior defining a divergent chamber and an exit chamber, and a back-mixing chamber is between the convergent nozzle and the throttle nozzle.

9. The gas-liquid reaction device according to claim 5, wherein the high-speed flow passages are circumferentially and uniformly distributed along a cross section of the cylinder in the hydraulic premixer; the micro-bubble generators are uniformly distributed in the hydraulic premixer along the circumference of the cross section of the cylinder.

10. The gas-liquid reaction device according to claim 5, further comprising a high-speed flow passage assembly and a low-speed flow passage assembly; the high-speed runner assembly comprises the high-speed runner and a high-speed runner limiting part, and the high-speed runner limiting part is fixedly connected with the barrel; the low-speed runner assembly comprises the low-speed runner and a low-speed runner limiting part, and the low-speed runner limiting part is fixedly connected with the barrel.

11. The gas-liquid reaction device according to claim 5, wherein the amount of the partial gas-phase feed per unit time is 1.01 to 1.3 times the amount of the gas-phase feed required for the liquid-phase feed to reach the gas-phase saturated dissolved concentration.

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