A particle collision disturbance type airlift loop reactor

Abstract

The present invention provides a particle collision disturbance type gas lift loop reactor, the reactor comprising: a reactor body; a draft tube with a sieve plate; particles, which can be suspended inside the draft tube when the reactor is running; a gas distributor; a main liquid distributor; a gas inlet; a liquid inlet; a gas outlet; and a liquid outlet. Compared with the traditional gas lift loop reactor, due to the turbulent disturbance of particles and fluid inside the draft tube of the reactor, it helps to prevent gas phase aggregation and increase liquid phase back mixing, so that the gas and liquid phases in the reactor are fully mixed, the solubility of the gas phase in the liquid phase and the gas-liquid contact area are increased, the mass transfer rate and heat transfer rate between fluids are improved, and at the same time, the temperature distribution in the reactor is uniform, which is conducive to gas-liquid two-phase reaction or gas-liquid-solid three-phase reaction, and can be widely used in gas-liquid two-phase or gas-liquid-solid three-phase chemical reaction processes.

Description

Technical Field

[0001] The invention relates to the technical field of chemical engineering, and relates to a particle collision disturbance type airlift loop reactor, which can be used for a gas-liquid two-phase or gas-liquid-solid three-phase reaction loop reactor. Background Art

[0002] For gas-liquid two-phase or gas-liquid-solid three-phase reactions, stirred tank or bubbling reactors are usually used. These two traditional reactors have low mass transfer efficiency and high energy consumption, which limits the reaction systems they can be applied to. During the reaction process, the effective mixing between gas-liquid two-phase or gas-liquid-solid three-phase, the gas holdup inside the reactor, the distribution of local gas holdup, the movement state of particles, etc. have an important influence on the mass and heat transfer efficiency of the reactor.

[0003] The airlift loop reactor evolved from the bubbling reactor. By installing a draft tube in the bubbling reactor, the density difference of the mixed fluid on both sides of the draft tube can achieve directional flow of the liquid in the reactor, so that the liquid in the reactor forms a circulation. At the same time, the uniform mixing of gas-liquid two-phase or gas-liquid-solid three-phase is achieved, thereby improving the mass transfer and heat transfer efficiency between the phases. This type of reactor has been widely used in fields such as chemical engineering.

[0004] The traditional airlift loop reactor still has some shortcomings, that is, the gas phase is easy to coalesce in the draft tube, thus forming many large bubbles, resulting in too short a residence time of the gas phase inside the reactor, and it is difficult to increase the overall gas holdup inside the reactor. In the annular gap area between the draft tube and the inner wall of the equipment body, since the buoyancy of large bubbles is greater than the drag force generated by the fluid, it is difficult for large bubbles to enter the annular gap area between the draft tube and the inner wall of the equipment body, resulting in a low gas holdup in the annular gap, a narrow adjustable range of operating parameters, low overall utilization of the reactor, and low reaction efficiency.

[0005] At the same time, the height-to-diameter ratio range of the traditional gaslift loop reactor is relatively narrow, generally around 6 to 8. When the height-to-diameter ratio is low, such as when the height-to-diameter ratio is 3, the residence time of the gas phase inside the draft tube is short, and the reaction conversion rate is low. When the height-to-diameter ratio is high, such as when the height-to-diameter ratio is 10, the local gas content inside the reactor will be unevenly distributed in the longitudinal direction, resulting in different reaction effects, and the reduction of the bottom gas content will lead to a reduction in the gas-liquid contact area, thereby reducing the utilization efficiency of the reactor. However, for different reaction systems, the height-to-diameter ratio range of the reactor designed for industrial applications is relatively wide, and the structural design of the traditional gaslift loop reactor limits its wide application in industries such as the chemical industry.

[0006] For the traditional gas-liquid two-phase oxidation reaction, the gas phase has a short residence time in the reactor, the gas holdup inside the reactor is low, and the solubility of the gas phase in the liquid phase is also low. The mass transfer rate between the gas and liquid phases is slow, resulting in a low conversion rate of the oxidation reaction. By increasing the gas holdup inside the reactor and increasing the residence time of the gas phase inside the reactor, the solubility of the gas phase in the liquid phase can be effectively increased, thereby improving the overall conversion rate of the oxidation reaction. By adding a mechanical stirring device inside the reactor, the disturbance of the liquid and gas phases inside the reactor can be increased, thereby increasing the gas holdup and residence time inside the reactor, but the stirring device increases the mechanical complexity and investment cost of the equipment and increases the danger of the oxidation reaction. Therefore, the flexibility and versatility of the airlift loop reactor in industrial applications are subject to certain restrictions, and improving the reaction rate by modifying the structure of the airlift loop reactor has become a very urgent industrial problem.

[0007] Different flow behaviors in an airlift loop reactor have a significant impact on the mixing and mass transfer process of the fluid. By changing the structure and size of the reactor, the flow behavior of the fluid in the reactor, the gas holdup and local gas holdup distribution inside the reactor, and the gas-liquid mass transfer area can be effectively changed, thereby improving the mass transfer and heat transfer efficiency and overall utilization of the reactor.

[0008] Patent publication CN1435275A describes a multi-stage loop reactor, which uses a multi-stage flow guide tube to form a flow state of a large loop enclosing a small loop. This improves the gas-liquid contact capacity in the reactor, increases the gas holdup, and makes the local gas holdup uniformly distributed, so that the reactor's mass transfer efficiency is improved and the heat transfer capacity is better.

[0009] Patent publication CN101249405A reports a circulating reactor with a porous draft tube, where gas and liquid can flow out from the gas distribution holes of the opening section of the draft tube and the top of the draft tube, flow downward along the annular gap between the draft tube and the reactor body, and enter the bottom of the draft tube to achieve the circulation of gas and liquid. The draft tube with an opening section can achieve a higher gas holdup at the bottom of the reactor, thereby improving the mass transfer and heat transfer efficiency of the fluid in the reactor.

[0010] Patent CN106552560B discloses a gaslift reactor with a spiral porous sieve plate, wherein the plate body of the spiral porous sieve plate is in a spiral ascending shape and has a plurality of sieve holes on the plate body, thereby realizing the diversion and bubble breaking of two-phase or three-phase flow. The invention utilizes the ejected gas to drive the liquid to realize the circulation flow, and at the same time can break the rising large bubbles into small bubbles, thereby effectively preventing the bubbles from coalescing, and increasing the gas holdup inside the reactor and the mass transfer coefficient between the fluids.

[0011] However, the conventional airlift loop reactors in the prior art have a relatively narrow height-to-diameter ratio range (6 to 8), which cannot meet the requirements of the occasions where an airlift loop reactor with a higher height-to-diameter ratio is required. Summary of the invention

[0012] The purpose of the present invention is to propose an improved airlift loop reactor based on the traditional airlift loop reactor. This reactor includes a guide tube with a sieve plate of different structures. The guide tube contains particles with a certain solid content and a density similar to that of the fluid. The particle disturbance in the guide tube improves the turbulent state of the fluid, thereby making the local gas content distribution uniform, and increasing the gas content and the residence time of the gas phase inside the reactor. At the same time, the density difference inside and outside the guide tube is improved, and the flow rate of the fluid inside and outside the guide tube is increased. The liquid enters the annular main liquid distributor from the main liquid inlet, and then sprays and flows downward, thereby increasing the circulation speed of the fluid inside and outside the guide tube. At the same time, the liquid passes through the auxiliary liquid distributor at the top of the guide tube from the auxiliary liquid inlet, and brings the gas phase coming out of the top of the guide tube into the annular gap between the guide tube and the reactor body, thereby improving the overall utilization rate of the reactor. Compared with the traditional gaslift loop reactor, the turbulent disturbance of particles and fluids inside the draft tube of this reactor helps to prevent gas phase aggregation and increase liquid phase backmixing, so that the gas-liquid two-phase mixing in the reactor is sufficient, the solubility of the gas phase in the liquid phase and the gas-liquid contact area are increased, the mass transfer rate and heat transfer rate between the fluids are improved, and at the same time the temperature distribution in the reactor is uniform, which is conducive to gas-liquid two-phase reaction or gas-liquid-solid three-phase reaction. It can be widely used in gas-liquid two-phase or gas-liquid-solid three-phase chemical reaction processes, such as oxidation reactions.

[0013] Compared with the narrow height-to-diameter ratio range (6 to 8) of the traditional airlift loop reactor, the height-to-diameter ratio range of the particle collision disturbance type airlift loop reactor according to the present invention is wider. When a high-height-to-diameter ratio airlift loop reactor is required in industrial applications, a multi-layer guide tube with sieve plates can be used, and different types of particles are placed in different layers therein, so as to ensure that the upper and lower local solid content distribution of the guide tube is uniform, and the reaction mass transfer and heat transfer effect is good. When a low-height-to-diameter ratio airlift loop reactor is required in industrial applications, a single-layer or multi-layer guide tube with sieve plates can be used, and particles with a smaller density than the fluid are placed inside the guide tube, so that the density difference inside and outside the guide tube is increased, and the fluid circulation speed inside and outside the guide tube is increased. By cleverly setting different layers of guide tubes with sieve plates and placing suitable types of particles therein, it can be more widely used in industry. At the same time, the particle disturbance inside the reactor has the disturbance effect of mechanical stirring. Compared with adding mechanical stirring equipment in the reactor, the guide tube with particles has a simpler design structure, more flexible size design, and is safer than stirring equipment.

[0014] For gas-liquid two-phase oxidation reactions, compared with traditional gaslift loop reactors, by designing multi-layer segmented areas and placing particles of different contents in the particle collision disturbance type gaslift loop reactor, the particle disturbance stirring can effectively increase the residence time, oxygen content and oxygen solubility of oxygen inside the reactor, while improving the liquid phase backmixing effect and the mass transfer efficiency between the gas and liquid phases, so that the local gas content distribution inside the reactor is uniform. In addition, the oxidation reaction has a large heat release. Through the disturbance stirring effect of the particles, the temperature distribution between the gas-liquid two-phase fluid is uniform, which increases the interphase heat transfer efficiency, thereby improving the overall conversion rate of the oxidation reaction and increasing the economic benefits of the equipment.

[0015] Therefore, according to the present invention, there is provided a particle collision disturbance type airlift loop reactor, the reactor comprising:

[0016] Reactor body 1;

[0017] A draft tube 2 with a sieve plate, the draft tube 2 with a sieve plate is located inside the reactor body 1 and is coaxial with the reactor body 1, the top and bottom of the draft tube 2 with a sieve plate are provided with a sieve plate with evenly distributed openings, and the outer diameter of the draft tube 2 with a sieve plate is smaller than the inner diameter of the reactor body 1;

[0018] Particles 3, which can be suspended inside the draft tube 2 when the reactor is running;

[0019] A gas distributor 4, which is located at the lower end of the reactor body 1 and below or inside the draft tube 2 with the sieve plate;

[0020] A main liquid distributor 5, which is located in the middle of the reactor body 1;

[0021] a gas inlet, which is connected to the gas distributor 4 and is used for feeding gas;

[0022] a liquid inlet, which is connected to the main liquid distributor 5 and is used to feed liquid;

[0023] a gas outlet, which is located at the top of the reactor body 1 and is used to discharge gas; and

[0024] A liquid outlet is located at the upper end of the reactor body 1 and is used to discharge liquid. The liquid outlet is located higher than the top of the draft tube 2 with the sieve plate.

[0025] Preferably, the guide tube 2 with the sieve plate has a shape selected from a cylindrical shape, a truncated cone shape and an hourglass shape.

[0026] The truncated cone shape means that the upper end diameter of the guide tube 2 with the sieve plate is larger than the lower end diameter, and preferably the ratio of the upper end diameter to the lower end diameter is 1-2.

[0027] The hourglass shape means that the diameters of the upper and lower ends of the guide tube 2 with the sieve plate are larger than the middle diameter, and preferably the ratio of the upper and lower end diameters to the middle diameter is 1 to 2.

[0028] Preferably, one or more intermediate sieve plates are arranged in the guide tube 2 with sieve plates, or a guide tube is arranged inside the guide tube 2 with sieve plates. Preferably, the ratio of the inner diameter of the guide tube with sieve plates to the inner diameter of the guide tube arranged inside the guide tube is 1.5 to 3. Preferably, the guide tube arranged inside the guide tube is a cylinder with both ends open (unsealed).

[0029] Preferably, the opening rate of the top sieve plate, the bottom sieve plate, and optionally one or more middle sieve plates of the guide tube 2 with sieve plates is 30% to 93%.

[0030] Preferably, the ratio of the total height of the reaction section of the reactor body 1 to the inner diameter is 0.5-20.

[0031] Preferably, the ratio of the average inner diameter of the guide tube 2 with a sieve plate to the inner diameter of the reactor body 1 is 0.3 to 0.9, and the average inner diameter of the guide tube 2 with a sieve plate means: when the guide tube 2 with a sieve plate is cylindrical, the average inner diameter is the inner diameter of the guide tube 2 with a sieve plate; when the guide tube 2 with a sieve plate is truncated cone-shaped or hourglass-shaped, the average inner diameter is the inner diameter of a cylinder of equal volume and height as the guide tube 2 with a sieve plate.

[0032] Preferably, the total height ratio of the draft tube 2 with sieve plates to the reaction section of the reactor body 1 is 0.5 to 0.9.

[0033] When designing a particle collision disturbance type airlift loop reactor, in order to determine the volume of particles added to the draft tube with a sieve plate, it is necessary to consider the pressure drop difference inside and outside the draft tube. Since there are three phases of gas, liquid and solid inside the draft tube with a sieve plate, the pressure drop of the fluid bed is related to the phase content of the three phases. Under a stable flow state, if it is assumed that the solid particles in the draft tube area of ​​each layer are only the combined effect of the drag force of the fluid and the gravity, and the friction loss between the particles is not considered, the axial pressure gradient (static pressure gradient) of the fluid bed is calculated as follows:

[0034]

[0035] ε s : Solid content

[0036] ε l : Liquid phase content

[0037] ε g : Gas phase holdup

[0038] ρ s: Solid phase density

[0039] ρ l : Liquid density

[0040] ρ g : Gas phase density

[0041] g: acceleration due to gravity

[0042] Since there are only two phases of gas and liquid outside the guide tube with sieve plate, the pressure drop of the fluid bed is only related to the phase content of the gas and liquid phases. Under the stable flow state, the calculation method of the axial pressure gradient (static pressure gradient) of the fluid bed is:

[0043]

[0044] ε l +ε g =1

[0045] When calculating the pressure drop difference between the inside and outside of the guide tube, the pressure drop of the screen plate of the guide tube must also be considered. The pressure drop of the fluid when passing through the screen plate Δp D The superficial velocity in the reactor can be calculated:

[0046]

[0047] C D : Resistance coefficient, which is related to the shape of the sieve plate; when the shape of the sieve plate is fixed, it can be regarded as a constant

[0048] α: Opening rate

[0049] U: Superficial speed

[0050] ρ f : Fluid density

[0051] g: acceleration due to gravity

[0052] The guide tube 2 with a sieve plate contains a certain volume of particles 3 with a suitable density and particle size. The particles 3 are distributed in the internal space of the guide tube divided by the sieve plate. In different sieve plate spaces inside the guide tube 2 with a sieve plate, particles 3 with different volume contents, densities and particle sizes can be used to achieve different flow states and mixing states of the fluid in each divided area. When determining the density and diameter of the particles, it is necessary to consider that the net weight of the particles (the difference between gravity and buoyancy) will be balanced by the friction resistance generated when the fluid flows over the surface of the particles. At this time, it is necessary to calculate the terminal velocity U of the particles. t :

[0053]

[0054] d p : Particle equivalent diameter

[0055] ρ p : Particle density

[0056] ρ f : Fluid density

[0057] C ds : Drag coefficient

[0058] At the same time, in order to ensure that the particles are suspended and flow inside the guide tube and determine the appropriate superficial gas velocity, it is necessary to calculate the critical fluidizing liquid velocity of the three-phase system, the critical fluidizing liquid velocity U Imf Calculation formula:

[0059]

[0060]

[0061]

[0062]

[0063] U lmf0 : Critical fluidization velocity of liquid-solid two-phase

[0064] g : Apparent gas velocity

[0065] μ l : Liquid phase viscosity

[0066] ρ l : Liquid density

[0067] A r : Archimedean number

[0068] When the liquid flow rate in each layered area in the guide tube with a sieve plate is greater than the critical fluidization liquid velocity of the particles in each layer, the particles can flow in each area, thereby improving the mixing state between the fluids and reducing the size of the bubbles.

[0069] A certain volume of particles 3 with appropriate density and particle size are suspended and collided in the draft tube 2 with a sieve plate due to the gas phase and liquid. The gas phase enters the draft tube 2 with a sieve plate, and the collision disturbance of the particles 3 prevents the gas phase from coalescing, and then the gas phase flows out from the top of the draft tube 2 with a sieve plate. After the liquid phase is evenly distributed by the liquid distributor 5, the gas phase is brought into the annular gap between the reactor body and the draft tube, and then the liquid phase enters the interior of the draft tube through the bottom of the draft tube 2 with a sieve plate.

[0070] Preferably, the average density of the particles 3 is similar to the density of the liquid in the reactor. Preferably, the average density of the particles 3 is 80% to 120% of the density of the liquid in the reactor, more preferably 90% to 110% of the density of the liquid in the reactor.

[0071] Preferably, the volume ratio of the particles 3 to the guide tube 2 with the sieve plate is 5% to 30%.

[0072] When the gas feed of the reactor is constant, the gas content and gas density in each layer of the guide tube with a sieve plate remain basically unchanged. By adjusting the content of particles in each layer (i.e., the solid content) and the density of the particles, while considering the density of the liquid phase, the pressure gradient change of the fluid bed in each layer of the guide tube can be adjusted.

[0073] When designing a reactor, when the height-to-diameter ratio of the reactor is low, the internal space of the draft tube can be divided into 1 to 3 layers of space, and particles of different contents can be placed in each of them. When the gas velocity at the outlet of the gas distributor is high, more particles can be placed in the bottom partition area of ​​the draft tube than in the top partition area. Since the gas phase velocity at the bottom is faster, the fluidization effect of the particles in the bottom area can be better. In the top partition area, the gas phase velocity is relatively low, so only a small amount of particles can be fluidized. When the height-to-diameter ratio of the designed reactor is high, such as 8 to 10, the interior of the draft tube can be divided into more areas according to the fluidization of the particles. Since the gas velocity flowing through the interior of the draft tube gradually decreases from bottom to top, the particle content in the partition area is gradually reduced from bottom to top. If the inlet gas velocity of the gas distributor is high, particles of different densities can be placed in different partition areas, and the density of particles placed from bottom to top gradually decreases. In different segmented areas, using particles with different contents and densities can make the local gas holdup distribution inside the draft tube uniform, and further improve the gas holdup, gas phase residence time, gas-liquid contact area, circulating fluid flow rate, and mass and heat transfer efficiency. At the same time, the particle content, density and particle size are adjustable, making the reactor design more flexible and suitable for a wide range of height-diameter ratio reactor designs.

[0074] Preferably, the gas distributor 4 can be a multi-hole distributor or a single-hole distributor.

[0075] Preferably, the main liquid distributor 5 is located in the middle of the annular gap between the draft tube 2 with sieve plates and the reactor body 1. Liquid is sprayed and flows downward from here, which can effectively increase the circulation speed of the fluid inside and outside the draft tube, thereby improving the mixing effect between the fluids.

[0076] Preferably, the ratio of the annular inner diameter of the main liquid distributor 5 to the inner diameter of the reactor body 1 is 0.7 to 0.95, and the opening rate is 5% to 30%.

[0077] Preferably, the airlift loop reactor also includes: an auxiliary liquid distributor 6 located above the guide tube 2 with a sieve plate and below the liquid outlet, and an auxiliary liquid inlet connected to the auxiliary liquid distributor 6 and used for feeding liquid, and the auxiliary liquid distributor 6 is coaxial with the guide tube 2 with a sieve plate.

[0078] Preferably, the auxiliary liquid distributor 6 is a cone, or two upper and lower cones with their bottom surfaces connected, the ratio of the inner diameter of the bottom circular surface of the cone to the upper inner diameter of the guide tube 2 with a sieve plate is 0.1 to 0.5, and the top angle of the cross section of the cone ranges from 60 to 150°.

[0079] The particle collision disturbance type airlift loop reactor of the present invention is characterized by:

[0080] 1. The particle collision disturbance type airlift loop reactor of the present invention comprises a reactor body 1, a guide tube 2 with a sieve plate, particles 3, a gas distributor 4, a main liquid distributor 5 and an optional auxiliary liquid distributor 6, as well as a feed port for feeding and a discharge port for discharging. The guide tube 2 with a sieve plate has a cylindrical shape, or an hourglass shape with the diameter of the upper and lower ends larger than the middle diameter, or a truncated cone shape with the diameter of the upper end larger than the diameter of the lower end, etc., and contains a sieve plate at the top and bottom or in the middle, and may also contain a small guide tube inside. The gas distributor 4 can be a multi-hole distributor or a single-hole distributor. The main liquid distributor 5 is annular, and holes are evenly opened on the annulus, so that the liquid is sprayed and flows downward, which can effectively increase the liquid phase circulation flow rate inside and outside the guide tube. The auxiliary liquid distributor 6 is conical, or the bottom surfaces of two upper and lower cones are connected. In different sieve plate spaces inside the draft tube 2 with sieve plates, particles 3 with different volume contents, different densities and different particle sizes can be used, so as to achieve different flow states and mixing states of the fluid in each divided area. When designing a reactor, when the height-diameter ratio of the reactor is low, the internal space of the draft tube can be divided into 1 to 3 layers of space, and particles of different contents can be placed in each of them. When the outlet gas velocity of the gas distributor is large, more particles can be placed in the bottom divided area of ​​the draft tube than in the top divided area. Since the bottom gas phase velocity is fast, the fluidization effect of the particles in the bottom area can be better. For the top divided area, the gas phase velocity is relatively low, so only a small amount of particles can be fluidized. When the height-diameter ratio of the designed reactor is high, such as around 8 to 10, the inside of the draft tube can be divided into more areas according to the fluidization of the particles. Since the gas velocity flowing through the inside of the draft tube gradually decreases from bottom to top, the particle content in the divided area is gradually reduced from bottom to top. If the inlet gas velocity of the gas distributor is large, particles of different densities can be placed in different divided areas, and the density of the particles placed in sequence from bottom to top gradually decreases. In different segmented areas, using particles with different contents and densities can make the local gas holdup distribution inside the draft tube uniform, and further improve the gas holdup, gas phase residence time, gas-liquid contact area, circulating fluid flow rate, and mass and heat transfer efficiency. At the same time, the particle content, density and particle size are adjustable, making the reactor design more flexible and suitable for a wide range of height-to-diameter ratios.

[0081] 2. The gas phase flows through the gas distributor 4 and enters the guide tube 2 with a sieve plate. Driven by the drag force of the gas phase and the liquid phase, the particles 3 are suspended and collided in the guide tube 2 with a sieve plate, thereby preventing the gas phase from agglomerating and increasing the turbulent disturbance of the fluid, so that the gas-liquid contact is sufficient, the local gas content is evenly distributed, and the gas content inside the reactor is increased. At the same time, the density difference inside and outside the guide tube is increased, and the flow rate of the fluid inside and outside the guide tube is accelerated. The liquid distributor above the guide tube 2 with a sieve plate guides the liquid to the annular gap between the reactor body 1 and the guide tube 2 with a sieve plate, and at the same time brings the gas phase into the annular gap, thereby improving the utilization rate of the reactor body.

[0082] 3. Due to the turbulent disturbance of the fluid in the reactor, it helps to prevent the gas phase from coalescing, so that the materials in the reactor are fully mixed, the mass transfer rate and heat transfer rate between the fluids are improved, the gas dissolution rate is higher, and the temperature distribution in the reactor is uniform, which is conducive to gas-liquid two-phase reaction and gas-liquid-solid three-phase reaction, such as oxidation reaction and other chemical production processes. At the same time, in the different spaces divided by the sieve plate inside the guide tube 2 with sieve plates, the use of particles 3 with different volume contents, different densities and different particle sizes can make each phase of the fluid achieve different mixing degrees and interphase mass transfer and heat transfer efficiencies, further broadening its practical application range in industrial production.

[0083] 4. For the oxidation reaction process, the use of a particle collision disturbance type gas lift circulation reactor can effectively increase the residence time, oxygen content and solubility of oxygen inside the reactor, while improving the liquid phase backmixing effect and the mass and heat transfer efficiency between the gas and liquid phases, and the local gas content is evenly distributed in the axial direction of the disturbance zone, thereby improving the overall conversion rate of the oxidation reaction and increasing the economic benefits of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] Figure 1 It is a structural diagram and flow state diagram of a particle collision disturbance type airlift loop reactor according to one embodiment of the present invention;

[0085] Figure 2 It is a structural diagram of a draft tube with a sieve plate and a flow state diagram of a particle collision disturbance type airlift loop reactor according to one embodiment of the present invention;

[0086] Figure 3 It is a structural diagram of a draft tube with a sieve plate and a flow state diagram of a particle collision disturbance type airlift loop reactor according to one embodiment of the present invention;

[0087] Figure 4 It is a structural diagram of a draft tube with a sieve plate and a flow state diagram of a particle collision disturbance type airlift loop reactor according to one embodiment of the present invention;

[0088] Figure 5It is a structural diagram of a draft tube with a sieve plate and a flow state diagram of a particle collision disturbance type airlift loop reactor according to one embodiment of the present invention;

[0089] Figure 6 It is a structural diagram of a draft tube with a sieve plate and a flow state diagram of a particle collision disturbance type airlift loop reactor according to one embodiment of the present invention;

[0090] Figure 7 It is a structural diagram of a draft tube with a sieve plate and a flow state diagram of a particle collision disturbance type airlift loop reactor according to one embodiment of the present invention;

[0091] Figure 8 It is a structural diagram of a draft tube with a sieve plate and a flow state diagram of a particle collision disturbance type airlift loop reactor according to one embodiment of the present invention;

[0092] Fig. 9 It is a structural diagram of a draft tube with a sieve plate and a flow state diagram of a particle collision disturbance type airlift loop reactor according to one embodiment of the present invention;

[0093] Fig.10 is a schematic sieve plate structure diagram of a draft tube with a sieve plate of a particle collision disturbance type airlift loop reactor according to one embodiment of the present invention;

[0094] Fig.11 It is a structural diagram of the main liquid distributor of a particle collision disturbance type airlift loop reactor according to one embodiment of the present invention. DETAILED DESCRIPTION

[0095] The present invention is described in detail below with reference to the accompanying drawings.

[0096] like Figure 1 As shown, the particle collision disturbance type gas lift loop reactor comprises: a reactor body 1; a draft tube 2 with a sieve plate, which is inside the reactor body 1 and coaxial with it; particles 3, which are located inside the draft tube 2 with a sieve plate; a gas distributor 4, which is located at the lower part or inside the draft tube 2 with a sieve plate; a main liquid distributor 5, which is located in the middle of the reactor body 1 and in the middle of the annular gap between the draft tube 2 with a sieve plate and the reactor body 1; an auxiliary liquid distributor 6, which is located at the upper part of the draft tube 2 with a sieve plate; a gas inlet, which is connected to the gas distributor 4 and is used to feed gas; a liquid inlet, which is connected to the main liquid distributor and is used to feed liquid; a gas outlet, which is located at the top of the reactor body 1 and is used to discharge gas; and a liquid outlet, which is located at the upper end of the reactor body and is used to discharge liquid, and the liquid outlet is located higher than the auxiliary liquid distributor 6.

[0097] The draft tube 2 with sieve plates is different from the draft tube in the conventional airlift loop reactor and can be cylindrical or hourglass-shaped with the diameters of the upper and lower ends being larger than the middle diameter (see Figure 6 ), or a truncated cone with a larger diameter at the top than at the bottom (see Figure 3 ) etc. The top and bottom or the middle of the guide tube 2 with a sieve plate includes a sieve plate, and a small guide tube may also be included therein. The particles 3 are located in the space separated by the sieve plate in the guide tube 2 with a sieve plate, and particles with different volume fractions, different densities and different particle sizes may be used in different spaces. At the same time, a small guide tube may be placed inside the guide tube 2 with a sieve plate to enhance the directional flow state of the fluid.

[0098] When the gas phase enters the reactor through the gas distributor 4, the gas phase first enters the guide tube 2 with a sieve plate, and the gas content in the guide tube 2 with a sieve plate is increased. Under the combined effect of the density difference of the mixed phase inside and outside the guide tube 2 with a sieve plate and the gas injection, the pressure inside the guide tube 2 with a sieve plate is less than the pressure outside the guide tube 2 with a sieve plate. At this time, the liquid inside the reactor will carry the gas into the guide tube from the bottom of the guide tube 2 with a sieve plate, and gradually form a stable internal circulation directional flow. Inside the guide tube 2 with a sieve plate, due to the flow of liquid and gas, the particles 3 are driven to suspend and collide, the turbulent disturbance of the fluid is increased, the coalescence between the gas phases is prevented, and the gas content inside the reactor is increased. The gas phase coming out from the top of the guide tube 2 with a sieve plate enters the annular gap between the reactor body 1 and the guide tube 2 with a sieve plate under the drive of the liquid guided by the top auxiliary liquid distributor 6, and realizes the flow state of internal circulation with the directional movement of the liquid. At the same time, the liquid phase enters the annular gap from the main liquid distributor 5 and flows downward by jetting, which can effectively increase the liquid phase circulation speed inside and outside the guide tube and increase the disturbance effect inside the reactor.

[0099] The gas holdup inside the reactor, the mixing state between the fluids, and the axial distribution of the gas holdup can be controlled by changing the length, shape, number of sieve plates, whether to add a small-sized draft tube, and the volume content, density, and particle size of the particles in different divided spaces of the draft tube 2 with sieve plates. For example, in the internal spaces of the draft tube divided by sieve plates in different axial directions, different particles with gradually reduced volume content, density, and particle size can be used to increase the gas holdup in each divided interval of the draft tube 2 with sieve plates, thereby increasing the overall gas holdup inside the reactor.

[0100] The embodiments of the present invention are described below, but the protection scope of the present invention is not limited to the following embodiments.

[0101] Example 1

[0102] Reference Figure 1A particle collision disturbance type gaslift loop reactor for gas-liquid two-phase reaction, comprising a reactor body 1 and a draft tube 2 with a sieve plate, wherein the ratio of the height of the reactor body 1 to the height of the draft tube 2 with a sieve plate is 1.5, and the ratio of the total height of the reaction section of the reactor body 1 to the inner diameter is 2.8; the ratio of the total height of the draft tube 2 with a sieve plate to the reaction section of the reactor body 1 is 0.8; and the ratio of the inner diameter of the reactor body 1 to the inner diameter of the draft tube 2 with a sieve plate is 1.25. An auxiliary liquid distributor 6 and a gas distributor 4 are placed on the upper and lower parts of the draft tube 2 with a sieve plate, respectively, and the ratio of the inner diameter of the auxiliary liquid distributor 6 (which is a cone with a cross-section vertex angle of 120°) to the inner diameter of the draft tube 2 with a sieve plate is 0.3, and the ratio of the inner diameter of the gas distributor 4 to the inner diameter of the draft tube 2 with a sieve plate is 1:3. A main liquid distributor 5 is placed in the middle of the reactor body 1 and in the annular gap between the draft tube 2 with the sieve plate and the reactor body 1, and the ratio of its inner diameter to the inner diameter of the reactor body 1 is 0.9. Figure 2 The interior of the guide tube 2 with a sieve plate is divided into three areas by the sieve plate, and spherical particles with a density close to that of liquid water and a particle size of 5 mm are placed from bottom to top, accounting for 15%, 10% and 5% of the volume of the internal space of the guide tube 2 with a sieve plate. Fig.10 Schematically shown in FIG. The opening rate of the top sieve plate, the opening rate of the middle sieve plate, and the opening rate of the bottom sieve plate of the draft tube 2 with sieve plates are all 85%. A part of the liquid phase water enters the annular gap of the reactor through the main liquid distributor 5, and the other part flows downward into the annular gap between the reactor body 1 and the draft tube 2 with sieve plates after passing through the auxiliary liquid distributor 6. The schematic diagram of the structure of the main liquid distributor 5 is shown in FIG. Fig.11 As shown, the main liquid distributor 5 is an annular tubular structure, in which a plurality of liquid outflow holes are evenly distributed, and the porosity is 25%. After the gas phase air is ejected through the pores of the gas distributor 4, a gas-liquid two-phase flow is formed and enters the interior of the guide tube through the sieve plate. The gas distributor 4 is an annular porous distributor. Driven and disturbed by the fluid drag, the suspended collision of solid particles can prevent the gas phase from coalescing. The liquid phase water and the gas phase flow out from the top of the guide tube through the sieve plate, and then enter the annular gap between the reactor body 1 and the guide tube 2 with the sieve plate driven by the drag of the liquid phase water flowing out of the liquid distributor, and a directional circulation flow occurs.

[0103] Figures 2 to 9 Different variants of the guide sleeve 2 with a screen plate are given.

[0104] Example 2

[0105] Reactor:

[0106] 1. The particle collision disturbance type airlift loop reactor described in Example 1; Volume: 10m 3;

[0107] Inert particles of different volumes are added to different layer areas. The particle density is similar to that of the liquid phase, and the particle size is about 5 mm.

[0108] 2. Traditional airlift loop reactor: It has the same structural dimensions as the particle collision disturbance type airlift loop reactor, but does not include particles, and the guide tube does not contain a sieve plate, and there is no auxiliary liquid distributor 6.

[0109] Oxidation reaction: Cumene + air → Cumene hydroperoxide

[0110] Reaction temperature: 110°C; reaction pressure: 4 bar;

[0111] Continuous operation, liquid space velocity: 12min, gas space velocity: 3min.

[0112] Table 1: Reaction conversion and product selectivity

[0113]

[0114] Under appropriate process conditions and reactor structure design, the particle collision disturbance type airlift loop reactor can increase the oxidation reaction conversion rate of cumene to 8.1% and the selectivity of cumene hydroperoxide to 89%. Compared with the traditional airlift loop reactor, the particle disturbance in the draft tube of the particle collision disturbance type airlift loop reactor increases the solubility of oxygen, the oxygen content inside the reactor, and the residence time of the gas phase. At the same time, the turbulent disturbance of the particles makes the gas-liquid contact sufficient, the local gas holdup is evenly distributed, the contact area and mass transfer efficiency between oxygen and fluid are increased, and the temperature distribution of the fluid is more uniform, thereby increasing the conversion rate and selectivity of the reactor.

Claims

1. A particle collision disturbance type airlift loop reactor, the reactor comprising: Reactor body (1); A draft tube (2) with a sieve plate, the draft tube (2) with a sieve plate is located inside the reactor body (1) and is coaxial with the reactor body (1), the top and bottom of the draft tube (2) with a sieve plate are both provided with a sieve plate with evenly distributed openings, and the outer diameter of the draft tube (2) with a sieve plate is smaller than the inner diameter of the reactor body (1); Particles (3), which can be suspended inside the draft tube (2) when the reactor is running, and the average density of the particles (3) is 80% to 120% of the density of the liquid in the reactor; A gas distributor (4), which is located at the lower end of the interior of the reactor body (1) and below or inside the draft tube (2) with the sieve plate; A main liquid distributor (5) is annular and located in the middle of the reactor body (1). The main liquid distributor (5) is located in the middle of the annular gap between the draft tube (2) with the sieve plate and the reactor body (1). The liquid from the main liquid distributor (5) is sprayed and flows downward. a gas inlet, which is connected to the gas distributor (4) and is used for feeding gas; a liquid inlet, which is connected to the main liquid distributor (5) and is used to feed liquid; a gas outlet, which is located at the top of the reactor body (1) and is used to discharge gas; A liquid outlet, which is located at the upper end of the reactor body (1) and is used to discharge liquid, and the position of the liquid outlet is higher than the top end of the guide tube (2) with the sieve plate; and An auxiliary liquid distributor (6) is located above the guide tube (2) with a sieve plate and below the liquid outlet, and an auxiliary liquid inlet is connected to the auxiliary liquid distributor (6) and used for feeding liquid. The auxiliary liquid distributor (6) is coaxial with the guide tube (2) with a sieve plate.

2. The particle collision disturbance type airlift loop reactor according to claim 1, wherein: The guide tube (2) with the sieve plate has a shape selected from a cylindrical shape, a truncated cone shape and an hourglass shape.

3. The particle collision disturbance type airlift loop reactor according to claim 2, wherein: One or more intermediate sieve plates are arranged in the guide cylinder (2) with the sieve plate, or a guide cylinder is arranged inside the guide cylinder (2) with the sieve plate; And / or, the opening rate of the top sieve plate, the bottom sieve plate, and optionally one or more middle sieve plates of the guide tube (2) with sieve plates is 30% to 93%.

4. The particle collision disturbance type airlift loop reactor according to claim 3, wherein: The ratio of the inner diameter of the guide tube with the sieve plate to the inner diameter of the guide tube arranged inside the guide tube is 1.5-3.

5. The particle collision disturbance type airlift loop reactor according to claim 1, wherein: The ratio of the total height of the reaction section of the reactor body (1) to the inner diameter is 0.5 to 20; And / or, the ratio of the height of the draft tube (2) with the sieve plate to the height of the reactor body (1) is 0.5 to 0.

9.

6. The particle collision disturbance type airlift loop reactor according to any one of claims 1 to 5, wherein: The ratio of the average inner diameter of the draft tube (2) with the sieve plate to the inner diameter of the reactor body (1) is 0.3 to 0.

9. When the draft tube (2) with the sieve plate is truncated cone-shaped or hourglass-shaped, the average inner diameter is the inner diameter of a cylinder with the same volume and height as the draft tube (2) with the sieve plate.

7. The particle collision disturbance type airlift loop reactor according to any one of claims 1 to 5, wherein: The average density of the particles (3) is 90% to 110% of the density of the liquid in the reactor; And / or, the volume ratio of the particles (3) to the guide tube (2) with the sieve plate is 5% to 30%.

8. The particle collision disturbance type airlift loop reactor according to any one of claims 1 to 5, wherein: The gas distributor (4) is a multi-hole distributor or a single-hole distributor.

9. The particle collision disturbance type airlift loop reactor according to any one of claims 1 to 5, wherein: The ratio of the annular inner diameter of the main liquid distributor (5) to the inner diameter of the reactor body (1) is 0.7 to 0.95, and the opening rate is 5% to 30%.

10. The particle collision disturbance type airlift loop reactor according to claim 1, wherein: The auxiliary liquid distributor (6) is a cone, or two upper and lower cones with their bottom surfaces connected, the ratio of the inner diameter of the bottom circular surface of the cone to the inner diameter of the top of the guide tube (2) with a sieve plate is 0.1 to 0.5, and the top angle of the cross section of the cone ranges from 60° to 150°.

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