CN105505749A - Air-liquid dual injection type airlift loop reactor - Google Patents

Abstract

The invention relates to an air-liquid dual injection type airlift loop reactor comprising a fermentation tank. The air-liquid dual injection type airlift loop reactor is characterized in that guide cylinders are arranged in the fermentation tank, a liquid ascending area is arranged inside each guide cylinder, a liquid descending area is arranged among the guide cylinders and the fermentation tank, an annular distribution pipe is mounted on the lower portion of the liquid ascending area and provided with a plurality of spray holes, one or more static spiral cutting devices are mounted at the bottom of the fermentation tank, and each static spiral cutting device is provided with an air-liquid mixture outlet, a fermentation liquid input inlet and a compressed air input inlet, wherein the compressed air input inlet is connected with an air source, the air-liquid mixture outlet is connected with the distribution pipe, and the fermentation liquid input inlet is connected with a circular liquid outlet in the bottom of the fermentation tank through a pipeline. The air-liquid dual injection type airlift loop reactor has the advantages that difficulties in mixed air-liquid delivery and air-liquid coupling of an airlift biological fermentation system are overcome, biological treatment capability of the airlift loop reactor can be given to full play maximally, treatment efficiency is improved and energy consumption is reduced.

Description

Gas-liquid double-jet airlift loop reactor

technical field

The invention relates to a gas-liquid double-jet airlift loop reactor, in particular to a gas-liquid double-jet airlift loop reactor based on gas-liquid micro-nano cutting and refining technology.

Background technique

The airlift loop reactor (ALR for short) is a reactor that uses a gas source as power to make liquids mix and circulate. It is the most widely used biological reaction equipment at present. Its working principle is to inject sterile air into the fermentation liquid through nozzles or spray holes, and the air bubbles are divided into fine pieces by the turbulent flow of the gas-liquid mixture, and at the same time, due to the decrease in the density of the formed gas-liquid mixture, it moves upward, and the gas holdup The small fermented liquid sinks to form a circular flow to realize mixing and mass transfer of dissolved oxygen. This type of reactor has the advantages of simple structure, low energy consumption, small shear stress, and good mixing. The airlift loop reactor is quite favorable for the mixing and mass transfer between the reactants. The airlift loop reactor is a new type of reactor improved from the bubble reactor, which combines the performance of the bubble bed and the stirred tank. Compared with the bubble bed reactor, the loop reactor has the characteristics of liquid directional flow , the complete suspension of solid particles can be achieved under a low superficial gas velocity, and it is currently used in many fields such as Fischer-Tropsch synthesis, one-step synthesis of methanol and dimethyl ether, gasoline desulfurization, heavy oil hydrogenation, and biological waste fermentation Liquid treatment and fermentation engineering, etc.

There are two types of ALR that have been applied in industry: internal circulation type and external circulation type. No matter which type of reactor, it is composed of four basic parts: ascending section, descending section, bottom and gas-liquid separator. The fluid flow characteristics vary from site to site, and matrix transfer, product formation, and heat exchange vary from site to site. Compared with these two types of reactors, the external circulation airlift reactor can install a heat exchanger in the downcomer zone to enhance heat transfer, which is convenient for the measurement and control of the ascending section and the descending section, and can also be installed between the ascending section and the descending section. Install a throttle valve to control the intake rate and liquid circulation rate. The internal circulation airlift reactor has a relatively compact structure. The guide cylinder can be made into multiple sections to enhance local and overall circulation. A sieve plate can also be installed in the guide cylinder to improve gas distribution and properly inhibit liquid circulation. speed.

Compared with other reactors, ALR has the advantages of simple structure, low shear force, high gas supply efficiency, large effective interface contact area, excellent fluidization effect, clear residence time of each phase, and high heat and mass transfer rate. . However, through research and practical application, it also has the following disadvantages: large initial investment; very large air throughput; poor interphase mixing contact; when the circulating organisms and operating conditions change, substrates, nutrients It cannot be consistent with the oxygen content; when foam appears, the effect of gas-liquid separation is very poor; the problem of mixing and gas-liquid coupling, that is, it is difficult to improve without changing the ventilation.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a gas-liquid double-jet air-lift loop reactor, which overcomes the difficulties of gas-liquid mixed transportation and gas-liquid coupling in the air-lift biological fermentation system, and maximizes the The biological treatment capacity of the airlift loop reactor is brought into play, the treatment efficiency is improved, and the energy consumption is reduced.

According to the technical solution provided by the present invention, a gas-liquid double-jet airlift loop reactor includes a fermenter, which is characterized in that: a guide tube is arranged in the fermenter, and the inside of the guide tube is a liquid rising area, There is a liquid descending area between the draft tube and the fermentation tank, and an annular distribution pipe is installed at the lower part of the liquid ascending area, and a plurality of spray holes are arranged on the distribution pipe; one or more static helical cutters are installed at the bottom of the fermentation tank The static spiral cutting device has a gas-liquid mixture outlet, a fermentation liquid input port and a compressed air input port, the compressed air input port is connected to the air source, the gas-liquid mixture outlet is connected to the distribution pipe, and the fermentation liquid input port is connected to the fermentation liquid through the pipeline. The outlet circulation port at the bottom of the tank is connected.

Further, a fermented liquid pump is provided between the fermented liquid input port of the static helical cutting device and the liquid outlet circulation port of the fermenter.

Further, the static helical cutting device includes a cutting tube, a mandrel is set in the center of the cutting tube, and a liquid guide cone is set at the liquid inlet end of the mandrel; several slices of cutting sheets that are spirally stacked in sequence are set on the mandrel; The liquid inlet end of the cutting tube is connected to the gas filling head, and an axial center gas filling device is installed in the gas filling head. The axial center gas filling device includes a tube seat installed on the gas filling head. The end is connected to the intake pipe, and a throttle seat is installed at the inner end of the air guide pipe, a throttle valve core is arranged in the throttle seat, and an air filling hole is arranged on the throttle seat.

Further, the cutting sheet has three or more blades.

Further, the cutting pieces are helically superimposed sequentially along the length direction of the mandrel to form three or more helices arranged in the length direction of the mandrel, and the blades of two adjacent cutting pieces are staggered by a certain angle according to the helical line equation. The sides form a stepped cutting edge.

Further, the helical shape formed by the helically superimposed cutting pieces adopts a variable pitch, the pitch of the liquid inlet end is greater than that of the liquid outlet end, and the pitch gradually decreases from the liquid inlet end to the liquid outlet end.

Further, the thickness of the cutting sheet is 0.08-5 mm.

Further, the air filling hole is coaxial with the axis of the air filling head and the cutting tube.

Further, a static mixer is installed between the gas filling head and the cutting pipe.

The present invention has the following advantages:

(1) The present invention cuts air macromolecules into micro-nano-scale small molecular mass substances through a static helical cutting device without a rotating power mechanism, and dissolves them in the fermentation liquid almost under normal temperature and pressure, with high dissolved oxygen content , the dissolved oxygen rate is 4-5 times higher than that of the traditional air-lift fermentation method, and the stability is good; the static spiral cutting device has no power rotating mechanism, the equipment cost is low, and it is easy to maintain, which can realize large-scale industrial production and application.

(2) The static spiral cutting device of the present invention can realize gas-liquid micro-nano cutting and refinement, and the gas-liquid is subjected to shear force in the three directions of XYZ of the cutting cavity; the boundary of the flow field is a stepped cutting edge formed by the helical cutting blade , under the action of a certain flow field and centrifugal force, the gas-liquid is subjected to the cutting force of the stepped cutting edge, and theoretically infinitely small-scale cutting can be realized.

(3) The present invention passes air through a static discretized spiral cutting device to quickly and efficiently cut and refine small air bubbles at the micro-nano level, greatly improving the dissolution efficiency of oxygen, and the amount of dissolved oxygen in the fermentation liquid can reach that of a traditional fermentation tank 4-5 times that of the gas-entraining method, and the stability of dissolved oxygen is good.

(4) The gas filling device of the present invention adopts a specially designed gas filling head and gas outlet. According to the theoretical analysis of the hydrodynamics of the laminar fluid flow around the cylinder, it can be known that the flow rate of the fermentation liquid in the area near the gas filling hole is close to 0, and the oxygen can Dissipate smoothly into the fermentation broth, and realize the uniform gas filling of the four cutting chambers of the spiral cutter. This gas filling method has high efficiency and uniform cutting and fineness.

(5) The present invention overcomes the difficulties of gas-liquid mixed transportation and gas-liquid coupling in traditional airlift bio-fermentation systems, and can realize aeration rate and gas-liquid mixed transportation of 1-10VVM.

Description of drawings

Fig. 1 is a schematic structural view of the gas-liquid double-jet airlift loop reactor of the present invention.

Fig. 2 is a schematic structural view of the static helical cutting device.

Fig. 3 is a schematic diagram of the cutting sheet.

Fig. 4 is a schematic diagram of the working state of the static helical cutting device.

detailed description

The present invention will be further described below in conjunction with specific drawings.

As shown in Figures 1 to 4: the gas-liquid double-jet airlift loop reactor includes a fermenter 1, a guide tube 2, a fermentation liquid pump 3, a distribution pipe 4, a static spiral cutting device 5, and a spray hole 6 , gas filling head 3-1, pipe seat 3-2, air guide pipe 3-3, sealing ring 3-4, sealing block 3-5, throttle seat 3-6, throttle valve core 3-7, gas filling hole 3 -8, flange 5-1, cutting tube 5-2, mandrel 5-3, guide cone 5-4, cutting piece 5-5, pressing block 5-6, lock nut 5-7, blade 5- 8 etc.

As shown in Figure 1, the gas-liquid double-spray type air-lift circulation reactor of the present invention comprises a fermenter 1, the material that the fermenter 1 adopts is SUS316L, and the nominal volume selects 500L for use; Flow tube 2, the flow guide tube 2 adopts the existing commercially available molybdenum system guide tube; the inside of the flow guide tube 2 is a liquid rising area, and between the flow guiding tube 2 and the fermenter 1 is a liquid descending area. An annular distribution pipe 4 is installed in the lower part of the rising area, and a plurality of spray holes 6 are arranged on the distribution pipe 4 .

One or more static spiral cutting devices 5 are installed at the bottom of the fermentor 1, the static spiral cutting device 5 has a gas-liquid mixture outlet, a fermentation broth input port and a compressed air input port, the compressed air input port and the air source Connect, the outlet of the gas-liquid mixture is connected with the distribution pipe 4, and the input port of the fermented liquid is connected with the liquid outlet circulation port at the bottom of the fermenter 1 through a pipeline; A fermented liquid pump 3 is arranged between the circulation ports, and the fermented liquid pump 3 adopts a commercially available sanitary stainless steel self-priming pump.

As shown in Figure 2, the static spiral cutting device 5 includes a cutting tube 5-2, the center of the cutting tube 5-2 is provided with a mandrel 5-3, and the liquid inlet end of the mandrel 5-3 is provided with a guide cone 5-4, The role of the liquid guide cone 5-4 is to make the gas-liquid mixed flow evenly, and can pass through the cutting tube 5-2 evenly after diffusion; on the said mandrel 5-3, several slices of cutting slices 5- 5. The central hole of the cutting piece 5-5 is in clearance fit with the mandrel 5-3, and the cutting piece 5-5 is fixed on the mandrel 5-3 by the pressure block 5-6 and the lock nut 5-7; the cutting piece There are three or more blades 5-8 on the 5-5 (four blades 5-8 in Fig. 4), and the cutting blades 5-5 are spirally stacked sequentially along the length direction of the mandrel 5-3 to form a blade formed by the mandrel 5-3. Three or more helices are arranged in the length direction, and the blades 5-8 of two adjacent cutting pieces 5-5 are staggered at a certain angle according to the helix equation, forming a stepped cutting edge on the side of the helix. The helical shape adopts a variable pitch, the pitch of the liquid inlet end is greater than that of the liquid outlet end, and the pitch gradually decreases from the liquid inlet end to the liquid outlet end. The thickness of the cutting sheet 5-5 is 0.08-5mm.

As shown in Figure 2, the gas filling head 3-1 is connected to the liquid inlet end of the cutting tube 5-2, and generally a static mixer is also installed between the gas filling head 3-1 and the cutting tube 5-2 (Fig. not shown in); Install an axial center gas filling device in the gas filling head 3-1, the axial center gas filling device includes a tube seat 3-2 installed on the gas filling head 3-1, the tube seat 3 In -2, an air guide tube 3-3 is set, and a sealing ring 3-4 and a sealing block 3-5 are arranged between the air guiding tube 3-3 and the pipe seat 3-2, and the sealing block 3-5 is fastened by nuts and screws; The outer end of the air guide pipe 3-3 is connected to the intake pipe, and the air intake pipe is connected to the air source. A throttle seat 3-6 is installed at the inner end of the air guide pipe 3-3, and a throttle valve core 3-6 is arranged in the throttle seat 3-6. 7. The gas filling hole 3-8 is set on the throttle seat 3-6. The gas filling hole 3-8 is coaxial with the axis of the gas filling head 3-1 and the cutting tube 5-2, and the coaxiality is less than 0.1mm, which can ensure the smooth flow of gas. Escaping into water.

The working principle of the present invention: the gas-liquid double-jet airlift circulation reactor described in the present invention adopts micro-nano cutting and refining technology, and the gas-liquid two-phase flow is cut and refined by the static spiral cutter 5 , cut the air macromolecules into micro-nano-scale small molecular mass substances, dissolve them in the fermentation broth through a small pressure and a certain flow field, and achieve high-efficiency dissolved oxygen almost under normal temperature and pressure. The efficiency is 4-5 times higher than that of the traditional air-lift fermentation aeration method. The fermented liquid has high oxygen content, stable oxygen content, and a half-life of 20 days. The preparation cost is low, the equipment is simple and convenient, and the maintenance is convenient.

The static helical cutting device 5 consists of thousands of cutting pieces rotated and stacked according to a variable pitch to form a discretized stepped helical surface. Utilizing the pressure and flow rate of the gas-liquid itself, the fermentation broth and air flow through the cutting cavity. Due to the special variable-pitch helical structure in the cutting cavity, the existence of three-dimensional velocity gradients in x, y, and z inside the fluid is formed, so the inside of the fluid is at x, The three directions of y and z are subjected to shear force; moreover, the fluid is in contact with the step-shaped spiral cutting edge formed by stacking discretized cutting sheets with a thickness of only 5mm on the boundary surface. Assuming that the fluid does not move, it is quite Because the blades of the infinite blades are cutting the fluid, the combined force of the two functions cuts the gas and liquid into small molecular mass substances of the micro-nano scale, and the nano-scale bubbles themselves are continuously pressurized and expanded, and finally burst and dissolve in the fermentation broth, increasing The amount of dissolved oxygen in the liquid in the fermenter.

The coaxiality of the gas filling hole 3-8 of the axial central gas filling device with the gas filling head 3-1 and the cutting tube 5-2 is less than 0.1mm, according to the hydrodynamic theory of laminar flow around a cylinder It can be seen from the analysis that the flow rate of the liquid in the area near the air filling holes 3-8 is close to 0, and the air can be smoothly dissipated into the fermentation liquid, so that the cutting chamber of the cutting tube can be uniformly filled with gas. This gas filling method has high efficiency and uniform cutting. Due to the action of the fluid, the area near the air filling hole will form a negative pressure effect. The air pressure is slightly lower than that under the hydraulic condition, and the air filling can also be smoothly realized, which reduces the energy consumption of the equipment. Tests have determined that the dissolved oxygen rate is 4-5 times that of the traditional air-lift fermenter compressed air direct aeration method.

The working process of the present invention: when the gas-liquid double-jet type air-lift circulation reactor is working, the pressurized air G is sprayed into the static variable-pitch helical cutter 5 through the gas-filling hole 3-8 of the gas-filling head 3-1, and the fermentation liquid is simultaneously The fermentation broth pump 3 is pumped into the static variable-pitch helical cutter 5, and the fermentation broth and air flow through the cutting cavity by using the pressure and flow rate of the fermentation broth and compressed air, so as to realize the cutting and mixing of gas and liquid at the micro-nano level, The gas-liquid mixture enters the inside of the draft tube 2 through the nozzle of the annular distribution pipe. The nano-scale bubbles are continuously pressurized and expanded, and finally burst and dissolve in the fermentation broth, which improves the dissolved oxygen rate, which is 4-5 times that of the traditional aeration method. The specific surface area of the micro-nano bubbles increases sharply, and the heat transfer, mass transfer and biochemical reaction process between the micro-nano bubbles and the liquid phase in the draft tube are sharply strengthened, and the two are in close contact to fully react. Since the density of the gas-liquid mixture formed in the draft tube will decrease, coupled with the kinetic energy of the compressed air, the liquid in the draft tube will flow upward; after reaching the upper liquid level of the reactor, the gas in a part of the gas-liquid mixture will G is discharged to the upper space of the reactor, because the liquid that discharges part of the gas flows through the upper part of the draft tube to the outside of the draft tube, and the liquid outside the draft tube will have a reduced gas holdup rate and an increased density after the gas is discharged, so The liquid will drop to the bottom of the reactor under gravity. At the bottom of the reactor, due to the high velocity of the liquid in the draft tube, the liquid with a small gas holdup will be sucked into the draft tube and then enter the riser to participate in the reaction, thereby forming a circulating flow to achieve mixing and mass transfer.

The static discretized variable-pitch helical cutter is the core component of the device, mainly composed of a variable-pitch helical cutting blade with a thickness of 0.08-5mm and a fixing device. This part can realize gas-liquid micro-nano cutting refinement and mixed delivery. The cavity of the static variable pitch helical cutter adopts a special variable pitch design, that is, the transition from the large pitch of the fluid inlet to the small pitch of the fluid outlet, and the 4 helical cutting chambers are cut by blades with a thickness of 0.08-5mm according to the helical line equation. Overlay formation. Due to the characteristics of the variable-pitch screw mechanism, the gas and liquid are subjected to shear forces in the three directions of space XYZ; the boundary of the flow field is the stepped cutting edge formed by the helical cutting blade, under the action of a certain flow field and centrifugal force. The air bubbles and fermented liquid are subjected to the cutting force of the stepped cutting edge, which can theoretically achieve infinitely small-scale cutting.

The schematic diagram of the working state of the static variable pitch helical cutter is shown in Figure 4. 7 is the fermentation liquid input port, 8 is the compressed air input port, and the compressed air input port 8 is connected with the air source. 9 is the outlet of the gas-liquid mixture, which is connected with the annular distribution pipe of the fermenter. Utilizing the pressure and flow rate of the fermentation broth and compressed air, the fermentation broth and air flow through the cutting chamber to realize the cutting and mixing of gas and liquid at the micro-nano scale. The nano-scale air bubbles are continuously pressurized and expanded, and finally burst and dissolve in the In the fermentation broth, the dissolved oxygen rate is 4-5 times that of the traditional air-lift fermenter aeration method. The contact specific surface area of the fermented liquid and the micro-nano bubbles in the guide tube increases sharply, which strengthens the heat transfer, mass transfer and biochemical reaction process of the two, and achieves the purpose of energy saving and emission reduction.

The main advantages of the present invention are as follows:

(1) Install the gas-liquid micro-nano static variable-pitch spiral cutter at the front end of the air nozzle of the air-lift fermenter. Under the same degree of gas refinement, the injection pressure and flow rate of the compressed gas can be greatly reduced to achieve the purpose of energy saving ( The compressed air injection speed of the traditional air-lift fermenter must reach more than 250~300m/s, so that the air bubbles can be divided into fine pieces by the turbulence of the vapor-liquid mixture to form a certain contact area). At the same time, the micro-nano air bubbles are continuously pressurized and expanded, and finally burst and dissolve in the fermentation broth, forming highly efficient dissolved oxygen. The dissolved oxygen rate is 4-5 times higher than that of the traditional air-lift fermentation aeration method. The specific surface area of the fermented liquid in the guide tube increases sharply in contact with the micro-nano bubbles, which strengthens the heat transfer, mass transfer and biochemical reaction process between the two, accelerates the biological fermentation speed, and improves the fermentation efficiency.

(2) Cutting and refining the gas and liquid consumes almost no power. Under normal temperature and pressure, the fermented liquid dissolves oxygen efficiently, and the dissolved oxygen rate increases by 4-5 times. The microbubbles are formed by physical cutting, and the dissolved oxygen produced is very stable. The dissolved oxygen decay rate in the liquid decays by 50% in 20 days, providing a stable oxygen source for the aerobic fermentation reaction, and will not form large bubbles. Foam stabilizes the fermentation process and increases productivity.

(3) The present invention forms a new type of biological treatment process based on gas-liquid micro-nano cutting and refinement technology and gas-liquid double-jet air-lift circulation reaction technology, forming a fine-molecularized, efficient and energy-saving New biological treatment process and method for emission reduction. Oxygen macromolecules in the air can be refined to the nanometer level, and are not easily released from the fermentation broth, which eliminates the defects of high energy consumption and low efficiency of the traditional air-lift fermentation technology and air direct aeration method, and improves the microorganism's ability to absorb organic matter. The decomposition speed is fast, and the energy consumption is 25-35% lower than that of traditional airlift bioreaction technology.

(4) The gas-liquid double-jet airlift loop reactor based on gas-liquid micro-nano cutting and refining dissolved oxygen technology can cut and refine industrial high-concentration macromolecular group harmful organic substances to the micro-nano level, with a large biological contact area , good homogeneous mixing, high mass transfer speed, can give full play to the decomposition of microorganisms, so that harmful organic substances can be fully decomposed.

Claims (9)

1. A gas-liquid double-jet airlift loop reactor, comprising a fermenter (1), characterized in that: a guide tube (2) is set in the fermenter (1), and the guide tube (2) The interior of the tank is a liquid rising area, and the area between the guide tube (2) and the fermenter (1) is a liquid falling area. An annular distribution pipe (4) is installed at the lower part of the liquid rising area, and multiple Spray hole (6); 1 or more static spiral cutting devices (5) are installed at the bottom of the fermenter (1), and the static spiral cutting device (5) has a gas-liquid mixture outlet, a fermentation liquid input port and a compression The air input port and the compressed air input port are connected to the air source, the gas-liquid mixture outlet is connected to the distribution pipe (4), and the fermentation liquid input port is connected to the liquid outlet circulation port at the bottom of the fermenter (1) through a pipeline. 2. The gas-liquid double-jet airlift loop reactor according to claim 1, characterized in that: the fermentation liquid input port of the static helical cutting device (5) and the liquid outlet of the fermenter (1) circulate A fermented liquid pump (3) is arranged between the mouths. 3. The gas-liquid double-jet airlift loop reactor according to claim 1, characterized in that: the static spiral cutting device (5) includes a cutting tube (5-2), a cutting tube (5-2) A mandrel (5-3) is set in the center, and a liquid guide cone (5-4) is set at the liquid inlet end of the mandrel (5-3); on the mandrel (5-3), several slices of spirally superimposed cutting piece (5-5); the gas filling head (3-1) is connected to the liquid inlet end of the cutting tube (5-2), and the axial center gas filling device is installed in the gas filling head (3-1). The air filling device to the center includes a tube base (3-2) installed on the gas filling head (3-1), an air guide tube (3-3) is arranged in the tube base (3-2), and the air guide tube (3-3) The outer end of the air guide pipe (3-3) is connected to the intake pipe, and the throttle seat (3-6) is installed at the inner end of the air guide pipe (3-3). An air filling hole (3-8) is set on the seat (3-6). 4. The gas-liquid double-jet airlift loop reactor according to claim 3, characterized in that: the cutting piece (5-5) has three or more blades (5-8). 5. The gas-liquid double-jet airlift loop reactor according to claim 3, characterized in that: the cutting pieces (5-5) are spirally stacked sequentially along the length direction of the mandrel (5-3) to form a core Three or more helices arranged in the length direction of the shaft (5-3), and the blades (5-8) of two adjacent cutting pieces (5-5) are staggered by a certain angle according to the helix equation, forming a ladder on the side of the helix shaped cutting edge. 6. The gas-liquid double-jet airlift loop reactor according to claim 3, characterized in that: the helical shape formed by the helically superimposed cutting pieces (5-5) adopts a variable pitch, and the pitch of the liquid inlet end is greater than The pitch of the liquid outlet, the pitch gradually decreases from the liquid inlet to the liquid outlet. 7. The gas-liquid double-jet airlift loop reactor according to claim 3, characterized in that: the thickness of the cutting piece (5-5) is 0.08-5mm. 8. The gas-liquid double-jet airlift loop reactor according to claim 3, characterized in that: the gas filling hole (3-8) and the gas filling head (3-1), cutting tube (5-2 ) axis coaxial. 9. The gas-liquid double-jet airlift loop reactor according to claim 3, characterized in that: a static mixing device is installed between the gas filling head (3-1) and the cutting tube (5-2) device.