Jet-type aerobic fermenter

Abstract

This utility model discloses a jet-type aerobic fermenter, including a tank body, a stirring shaft along the tank body axis, and multiple stirring blades on the stirring shaft. An annular air distribution pipe, coaxial with the tank body, is located at the center of the bottom of the tank body. A compressed air supply pipe passes through the side wall of the tank body and connects to the annular air distribution pipe. The inner circumference of the annular air distribution pipe has two rows of symmetrically arranged air distribution holes. Each upper row of air distribution holes is equipped with an upward-pointing jet stirring head, and each lower row of air distribution holes is equipped with a downward-pointing jet stirring head. The jet stirring heads are evenly and centrally symmetrically distributed along their respective circumferences, and the nozzles of each jet stirring head tangentially point to the same cylindrical surface centered on the tank body axis. The annular air distribution pipe has two or more rows centered on the tank body axis. This jet-type aerobic fermenter can effectively reduce aeration pressure, increase dissolved oxygen, while reducing stirring power and operating energy consumption.

Description

Technical Field

[0001] This utility model relates to a fermenter, and more particularly to a jet-type aerobic fermenter, belonging to the technical field of fermentation equipment. Background Technology

[0002] In the field of biochemical engineering, the preparation of citric acid or lysine requires aerobic fermentation, and oxygen is needed for aerobic cell growth and biosynthesis. The more vigorous the cell growth, the greater the oxygen demand. The dissolved oxygen content in the feed solution is related to the aeration rate of the fermenter, the stirring power, and the viscosity of the fermentation broth. Therefore, to increase the oxygen content in the feed solution, it is necessary to increase the stirring power and the aeration rate. However, with any traditional aeration distribution device, the bubble diameter increases with the increase of the aeration rate, and the bubble rising speed also increases accordingly; but the degree of bubble fragmentation does not increase with the increase of the stirring speed, it can only remain at a certain order of magnitude. Therefore, simply increasing the aeration rate and stirring power will not only fail to significantly improve the oxygen volumetric mass transfer coefficient, but will instead lead to a large consumption of energy and an increase in product costs.

[0003] Traditional aerobic fermentation involves setting a specific aeration ratio based on the aerobic requirements of different microbial strains, with the aeration volume simply meeting the demand. Traditional air distributors, using a ring or straight pipe design, are horizontally arranged along the tank bottom, with multiple air distribution ports. The port diameters are very small, often leading to pore blockage for high-viscosity materials, thus affecting aeration efficiency. Furthermore, traditional air distributors only consider the aeration volume parameter, adjusting the pipe diameter and airflow to meet process requirements. Many fail to consider the coordination with the stirring system, unnecessarily increasing energy consumption.

[0004] Chinese utility model patent CN 217202695U discloses an "aeration device for a citric acid fermenter," comprising an air inlet pipe, an air distribution box, an aeration pipe, an aeration branch pipe, and an aeration head located at the bottom of the fermenter. The air inlet pipe connects to the air distribution box, which in turn connects to several aeration pipes. Each aeration pipe connects to several aeration branch pipes, and the aeration heads are evenly distributed on the aeration pipes and branch pipes. Each aeration head includes a floating ball, a perforated blind plate, and aeration holes. The floating ball floats up and down within the aeration head. This device innovatively designs its air distributor through a novel arrangement and the addition of a floating ball within the aeration head to prevent clogging. However, it does not specifically explain how it increases the dissolved oxygen level in the feed liquid or how it reduces the energy consumption of aeration and stirring. The innovation in the arrangement alone cannot effectively solve the energy consumption problem; the added floating ball device may actually increase aeration energy consumption.

[0005] Chinese utility model patent CN 215757292U discloses a "citric acid fermentation stirring device". The device features a transmission system at the top of a cylindrical body, driving a stirring shaft to rotate. The stirring shaft is located within the cylindrical body and has multiple stirring layers. An air intake assembly is located at the bottom of the cylindrical body, comprising multiple air rings arranged on the same horizontal plane and coaxially. Each air ring has an upper air hole and a lower air hole on its inner side. The patent claims that its air distributor works in close coordination with the stirring system, utilizing the driving force of the air intake system to rotate the stirring impeller, thereby reducing the fluid resistance of the stirring system and lowering power consumption. The air distributor is located at the bottom of the device, in the same area as the radial flow impeller of the lowest layer of the stirring system. However, the air pipe distribution shows that the upper and lower air holes are only inclined at 0-90° on a two-dimensional plane in each cross-section, with all air pipes pointing towards the center. The stirring at the bottom of the stirring system is a radial flow field, which passes directly through the effective range of the air bubbles in the air distributor, resulting in limited driving force. Utility Model Content

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, and such simplifications or omissions should not be construed as limiting the scope of the present invention.

[0007] In view of the problems existing in the above and / or prior art, this utility model is proposed.

[0008] The purpose of this invention is to overcome the problem in the existing technology that the diameter of bubbles in the aeration device of the fermenter increases with the increase of the aeration volume, and to provide a jet-type aerobic fermenter that can effectively reduce the aeration pressure, increase the dissolved oxygen volume, and at the same time reduce the stirring power and operating energy consumption.

[0009] To solve the above technical problems, this utility model provides a jet-type aerobic fermenter, including a tank body, a stirring shaft along the tank body axis, multiple stirring blades on the stirring shaft, an annular air distribution pipe coaxial with the tank body at the bottom center, a compressed air supply pipe passing through the side wall of the tank body and connected to the annular air distribution pipe, two rows of air distribution holes symmetrically arranged on the inner circumference of the annular air distribution pipe, each upper row of air distribution holes is equipped with a jet stirring head with an upward-sloping nozzle, each lower row of air distribution holes is equipped with a jet stirring head with a downward-sloping nozzle, each jet stirring head is evenly and centrally symmetrically distributed along its circumference, and the nozzle of each jet stirring head points tangentially to the same cylindrical surface centered on the tank body axis.

[0010] Furthermore, the annular gas distribution pipe has two or more channels centered on the tank axis.

[0011] Furthermore, the angle between the axis of each jet agitator and the horizontal plane is 30° to 80°, and the angle between the axis of each jet agitator and the normal to the circumference of its location in the top view is 30°.

[0012] Furthermore, the jet stirring head includes an interface, a diffuser, a converging tube, a low-pressure ejector section, and a diffuser. The root of the interface is fixedly connected to the corresponding air distribution hole of the annular air distribution pipe. The outer port of the interface is connected to the small-diameter end of the diffuser. The large-diameter end of the diffuser is connected to one end of the low-pressure ejector section, and the other end of the low-pressure ejector section is connected to the inner port of the diffuser. Multiple fermentation liquid inlets are evenly provided on the circumference of the low-pressure ejector section. The large end of the converging tube is welded to the inner wall of the middle section of the diffuser, and the small end of the converging tube extends to the middle of the low-pressure ejector section.

[0013] Furthermore, the middle section of the diffuser tube is provided with a throat, and the inner diameter of the outer port is larger than the inner diameter of the inner port.

[0014] Compared to the prior art, the advantages or beneficial effects of the embodiments of this application include at least the following: 1. Add a jet stirring device to the air pipe of the air distributor to make fuller use of the energy of compressed air. The jet stirring device adsorbs the fermentation liquid, transfers energy and mass, and achieves intense mixing and oscillation at the throat of the nozzle diffuser to form a group of small bubbles. 2. The spray stirring device allows for full utilization of oxygen in the deep fermentation broth and reduces the operating pressure of the fermenter by more than 50% compared to traditional fermenters. 3. The tangential arrangement of the nozzles on the vent pipe around the circumference has a synergistic effect on the stirring system, reducing stirring power, reducing power consumption, shortening fermentation time, and increasing fermentation efficiency. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The drawings are provided for reference and illustration only and are not intended to limit this utility model. Wherein: Figure 1 This is a perspective view of the jet-type aerobic fermenter of this utility model; Figure 2 This is a perspective view of the annular air distribution pipe in this utility model; Figure 3 This is a top view of the annular air distribution pipe in this utility model; Figure 4 for Figure 3A sectional view along the middle AA; Figure 5 This is a partially enlarged view of the annular air distribution pipe in this utility model; Figure 6 This is a perspective view of the jet stirring head in this utility model; Figure 7 This is a cross-sectional view of the jet mixing head in this utility model; Reference numerals: 1. Tank body; 2. Stirring motor; 3. Stirring reducer; 4. Stirring shaft; 5. Stirring blade; 6. Stirring support frame; 7. Compressed air supply pipe; 8. Annular air distribution pipe; 9. Jet stirring head; 9a. Interface; 9b. Diverging pipe; 9c. Converging pipe; 9d. Low-pressure ejector section; 9e. Fermentation broth inlet; 9f. Diffusion pipe. Detailed Implementation

[0016] In the following description of this utility model, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not mean that the device must have a specific orientation.

[0017] To make the technical means, creative features, achieved objectives and effects of this utility model easier to understand, the present utility model will be further described below with reference to specific illustrations. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0019] like Figures 1 to 7 As shown, the jet-type aerobic fermenter of this utility model includes a tank body 1. A stirring reducer 3 is installed at the top center of the tank body 1. The input end of the stirring reducer 3 is driven by a stirring motor 2. The output end of the stirring reducer 3 is connected to a stirring shaft 4. The stirring shaft 4 extends downward along the axis of the tank body 1. Multiple stirring blades 5 are provided on the stirring shaft 4, and at least two stirring support frames 6 are provided along the height direction of the stirring shaft 4. The two ends of the stirring support frames 6 are respectively supported on the inner wall of the tank body 1.

[0020] A ring-shaped air distribution pipe 8, coaxial with the bottom center of the tank body 1, is provided. There are two or more ring-shaped air distribution pipes 8 centered on the axis of the tank body 1. A compressed air supply pipe 7 passes through the side wall of the tank body 1 and connects to each ring-shaped air distribution pipe 8. Each ring-shaped air distribution pipe 8 has two rows of air distribution holes symmetrically arranged on its inner circumference. Each upper row of air distribution holes is equipped with an upward-pointing spray agitator head 9, and each lower row of air distribution holes is equipped with a downward-pointing spray agitator head 9. The angle between the axis of each spray agitator head 9 and the horizontal plane is 30° to 80°.

[0021] Each spray agitator head 9 is evenly and centrally symmetrically distributed along its circumference, with the nozzle of each spray agitator head 9 pointing tangentially towards the same cylindrical surface centered on the axis of the tank body 1. The angle between the axis of each spray agitator head 9 and the normal to its circumference in the top view is 30°. On one hand, each spray agitator head 9 blows air tangentially towards the same cylindrical surface in each revolution, supplying oxygen to the inoculum. On the other hand, the airflow agitates the fermentation broth and causes it to rotate in the same direction as the rotation of the agitator blades 5, thus pushing the agitator and reducing the agitation power.

[0022] The jet stirring head 9 includes an interface 9a, a diffuser 9b, a converging tube 9c, a low-pressure ejector section 9d, and a diffuser 9f. The root of the interface 9a is fixedly connected to the corresponding air distribution hole of the annular air distribution pipe 8. The outer port of the interface 9a is connected to the small-diameter end of the diffuser 9b, the large-diameter end of the diffuser 9b is connected to one end of the low-pressure ejector section 9d, and the other end of the low-pressure ejector section 9d is connected to the inner port of the diffuser 9f. Multiple fermentation broth inlets 9e are evenly distributed on the circumference of the low-pressure ejector section 9d. The large end of the converging tube 9c is welded to the inner wall of the middle section of the diffuser 9b, and the small end of the converging tube 9c extends to the middle of the low-pressure ejector section 9d. The middle section of the diffuser 9f has a throat, and the inner diameter of the outer port is larger than the inner diameter of the inner port.

[0023] When compressed air at a pressure of P1 is ejected from the nozzle of the converging tube 9c, its static pressure energy is converted into velocity energy, simultaneously reducing the pressure at the fermentation broth inlet 9e to P2, creating a low-pressure region. Under the jetting action of the compressed air, the fermentation broth is drawn in and enters the diffuser tube 9f along with the air. At the throat of the diffuser tube 9f, the gas and liquid phases develop from initial mixing to intense mixing and oscillation, producing gas "dynamic atomization" and "pressure atomization" phenomena. This causes the fermentation broth and air to be broken down into a large number of tiny particles, creating a highly turbulent, expanded, and constantly renewing interface between the gas and liquid.

[0024] The bubble diameter decreases with increasing airflow or nozzle thrust (P1-P2), intensifying the agitation. Subsequently, as the expansion cross-section of diffuser 9f increases, the flow velocity decreases, and the static pressure energy gradually recovers. Relying on the pressure and density differences at the inlet and outlet of diffuser 9f, and aided by the tangential arrangement of each jet agitator head 9, the gas-liquid two-phase mixture generates a radial, full-circulation jet swirling motion consistent with the rotation direction of the mechanical agitator.

[0025] After the bubbles are ejected from the diffuser tube 9f of the jet stirring head 9, their diameter increases due to collisions and merging. When the bubbles rise and meet the stirring blades 5 at the bottom of the equipment, they are broken up again and mixed with the fermentation liquid.

[0026] The above description is merely a preferred embodiment of the present utility model, showing and describing the basic principles, main features, and advantages of the present utility model. It is not intended to limit the scope of patent protection of the present utility model. Those skilled in the art should understand that the present utility model is not limited to the above embodiments. In addition to the above embodiments, the present utility model may have other implementations without departing from the spirit and scope of the present utility model. Various changes and improvements to the present utility model are also possible. All technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of protection claimed by the present utility model. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents. Technical features not described in the present utility model can be implemented by or using existing technology, and will not be elaborated here.

Claims

1. A jet-type aerobic fermenter, comprising a tank body, a stirring shaft arranged along the axis of the tank body, and multiple stirring blades arranged on the stirring shaft, characterized in that: The bottom center of the tank is provided with an annular air distribution pipe coaxial with the tank body. The compressed air supply pipe passes through the side wall of the tank body and is connected to the annular air distribution pipe. The inner circumference of the annular air distribution pipe is symmetrically provided with two rows of air distribution holes. Each upper row of air distribution holes is equipped with a jet stirring head with an upward-sloping nozzle, and each lower row of air distribution holes is equipped with a jet stirring head with an downward-sloping nozzle. Each jet stirring head is evenly distributed along its circumference and is centrally symmetrical. The nozzle of each jet stirring head points tangentially to the same cylindrical surface centered on the axis of the tank body.

2. The jet-type aerobic fermenter according to claim 1, characterized in that: The annular gas distribution pipe has two or more sections centered on the tank axis.

3. The jet-type aerobic fermenter according to claim 1, characterized in that: The angle between the axis of each jet agitator and the horizontal plane is 30° to 80°, and the angle between the axis of each jet agitator and the normal to the circumference of the circle in the top view is 30°.

4. The jet-type aerobic fermenter according to claim 1, 2, or 3, characterized in that: The jet stirring head includes an interface, a diffuser, a converging tube, a low-pressure ejector section, and a diffuser. The root of the interface is fixedly connected to the corresponding air distribution hole of the annular air distribution tube. The outer port of the interface is connected to the small-diameter end of the diffuser. The large-diameter end of the diffuser is connected to one end of the low-pressure ejector section, and the other end of the low-pressure ejector section is connected to the inner port of the diffuser. Multiple fermentation liquid inlets are evenly provided on the circumference of the low-pressure ejector section. The large end of the converging tube is welded to the inner wall of the middle section of the diffuser, and the small end of the converging tube extends to the middle of the low-pressure ejector section.

5. The jet-type aerobic fermenter according to claim 4, characterized in that: The diffuser tube has a throat in the middle section, and the inner diameter of the outer port is larger than the inner diameter of the inner port.

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