阅读说明：本技术 基于水力与超声空化的微藻油脂提取装置 (Microalgae grease extraction device based on hydraulic power and ultrasonic cavitation ) 是由 孙逊 玄晓旭 陈颂英 游炜彬 杨泽 王梦洁 于 2020-12-11 设计创作，主要内容包括：一种基于水力与超声空化的微藻油脂提取装置,包括定子、转子、转轴和超声波换能器,定子为密封筒体,定子内壁上分布有超声换能器,定子两侧分别设置有排液口和进液口,转轴安装在定子中,转子处于定子中并安装在转轴上,转子上分布有叶片,叶片内带有空腔,空腔相对的两侧分布有空化通孔。未破壁微藻细胞原料与所需液体搅拌混合,得到藻泥混合液,混合液述送至上述装置中,通过水力空化和超声空化对其处理,实现微藻细胞壁的破裂,经分离装置分离,最终得到微藻细胞内的油脂。上述装置通过水力空化和超声空化协同对微藻细胞进行破壁,效果好、可放大性高、处理量大、可连续作业、成本低、不产生二次污染,在微藻提取油脂领域具有广阔的应用前景。(The microalgae grease extraction device comprises a stator, a rotor, a rotating shaft and an ultrasonic transducer, wherein the stator is a sealed cylinder, the ultrasonic transducer is distributed on the inner wall of the stator, a liquid discharge port and a liquid inlet are respectively arranged on two sides of the stator, the rotating shaft is installed in the stator, the rotor is positioned in the stator and installed on the rotating shaft, blades are distributed on the rotor, cavities are formed in the blades, and cavitation through holes are distributed on two opposite sides of the cavities. Stirring and mixing the raw material of the microalgae cells without wall breaking with the required liquid to obtain a mixed solution of the microalgae mud, conveying the mixed solution into the device, treating the mixed solution by hydrodynamic cavitation and ultrasonic cavitation to realize the rupture of the microalgae cell walls, and separating the mixed solution by a separating device to finally obtain the grease in the microalgae cells. The device breaks the wall of the microalgae cells by the cooperation of hydrodynamic cavitation and ultrasonic cavitation, has good effect, high amplifiability, large treatment capacity, continuous operation, low cost and no secondary pollution, and has wide application prospect in the field of extracting oil from microalgae.)

1. A microalgae oil extraction device based on hydraulic power and ultrasonic cavitation is characterized in that: the ultrasonic motor comprises a stator, a rotor, a rotating shaft and an ultrasonic transducer, wherein the stator is a sealed cylinder, the ultrasonic transducer is distributed on the inner wall of the stator, a liquid discharge port and a liquid inlet are respectively arranged on two sides of the stator, the rotating shaft is installed in the stator, the rotor is located in the stator and installed on the rotating shaft, blades are distributed on the rotor, cavities are formed in the blades, and cavitation through holes are distributed on two opposite sides of the cavities.

2. The microalgae oil extraction device based on hydraulic power and ultrasonic cavitation of claim 1, which is characterized in that: the ultrasonic transducers are embedded in the inner wall of the stator at equal intervals along the axial direction and the circumferential direction, and 2-8 ultrasonic transducers are embedded in each circle for 2-6 circles; the ultrasonic transducer is connected with an ultrasonic generator, the frequency of the ultrasonic generator is 40-80 kHz, and the single-machine power is 1500-3000W.

3. The microalgae oil extraction device based on hydraulic power and ultrasonic cavitation of claim 1, which is characterized in that: the liquid inlet flow of the liquid inlet is 1.5-4.5 m³/h。

4. The microalgae oil extraction device based on hydraulic power and ultrasonic cavitation of claim 1, which is characterized in that: the rotating speed of the rotating shaft is 4000-4500 r/min.

5. The microalgae oil extraction device based on hydraulic power and ultrasonic cavitation of claim 1, which is characterized in that: the rotor is equidistantly distributed 2-6 in the rotating shaft, and the blades are equidistantly distributed on the rotor along the circumferential direction at 4-10 intervals.

6. The microalgae oil extraction device based on hydraulic power and ultrasonic cavitation of claim 1, which is characterized in that: the inner diameter of the stator is 300-600 mm, the width of the stator is 200-500 mm, and the wall thickness of the stator is 15-40 mm; the reaction temperature in the stator is 50-80 ℃, the length of the blade is 50-200 mm, the width of the blade is 30-60 mm, and the thickness of the blade is 10-30 mm.

7. The microalgae oil extraction device based on hydraulic power and ultrasonic cavitation of claim 1, which is characterized in that: the axial line of the cavitation through hole is consistent with the rotation tangential direction of the rotor.

8. The microalgae oil extraction device based on hydraulic power and ultrasonic cavitation of claim 1, which is characterized in that: the cavitation through hole is of a Venturi-shaped structure, an outlet and an inlet are respectively formed in two ends of the cavitation through hole, a throat part is formed in the middle of the cavitation through hole, the inner diameters of the outlet and the inlet are 1-6 mm, and the inner diameter of the throat part is 0.4-1 mm; the contraction angle is 35-50 degrees, and the expansion angle is 8-15 degrees.

9. The microalgae oil extraction device based on hydraulic power and ultrasonic cavitation of claim 1, which is characterized in that: the cavitation through holes are arranged in 4-10 rows and 3-10 rows of rectangular arrays on two sides of the inner cavity of the blade, and the cavitation through holes on two sides of the cavity in the blade are oppositely arranged and aligned pairwise.

10. The microalgae oil extraction device based on hydraulic power and ultrasonic cavitation of claim 1, which is characterized in that: the surface roughness Ra of the inner wall of the cavitation through hole is smaller than 1.6 mm.

Technical Field

The invention relates to a device for extracting microalgae grease through hydraulic power and ultrasonic cavitation, and belongs to the technical field of microalgae grease extraction.

Background

The microalgae has the characteristics of high photosynthetic efficiency, strong environmental adaptability, short production period, high yield, high content of certain grease and the like, and becomes one of potential raw materials for preparing the biodiesel. Oil is contained in microalgae cells, but because the microalgae cells are small and have cell wall structures, how to break the microalgae cell walls is a difficulty in extracting the microalgae oil at present.

At present, the most common cell wall breaking methods include a high-pressure homogenization method, a freeze-thaw method, an ultrasonic method, an organic solvent method, a grinding method, a microwave heating method, a complex enzyme method and the like. However, the method has the problems of various steps, limited application range, overhigh energy consumption, long wall breaking time, low wall breaking efficiency, difficult realization of wall breaking industrialization and the like.

Cavitation refers to the process of formation, development, and collapse of gas cavities within a liquid or at a liquid-solid interface when the local pressure within the liquid drops. When the liquid pressure drops to or below the liquid saturation vapor pressure, a large number of cavitation bubbles are generated due to the vigorous vaporization of the liquid. The cavitation bubbles expand and grow along with the flow of the liquid. When the liquid pressure recovers, the cavitation bubbles are instantaneously collapsed to form micro jet and impact waves, and local high temperature and high pressure are instantaneously generated. The energy released by cavitation can be used to break the cell wall directly or indirectly.

Chinese patent CN105420092A has coupled hydrodynamic cavitation and impinging stream technique, make two strands of cavitation efflux that carry a large amount of cavitation bubbles flow in opposite directions and strike, make full use of the instant microjet that the cavitation collapses and produces, shock wave and impact area collision, strong turbulence and pressure fluctuation that shear and extrusion formed, the strong turbulence of impact area has increased the turbulent flow condition that the cavitation takes place, make the cavitation take place in the impact area continuously, has improved the broken wall effect greatly, and device simple structure, the running cost is low, easily realize the industrialization.

CN103396895A utilizes ultrasonic radiation to make liquid flow to generate cavitation, utilizes the pressure difference and agitation caused by high temperature and high pressure generated by cavitation and extremely high cooling rate to well mix the liquid together, thereby assisting the enzyme to extract the grease.

CN102245749A provides a continuous flow of a fluid medium containing one or more microalgae to a hydrodynamic cavitation device, applies sufficient turbulence to generate hydrodynamic cavitation to disrupt one or more microalgae cells, releases microalgae oil from the microalgae into the medium, and extracts microalgae oil from the medium.

The prior microalgae oil extraction technology has the following problems:

1. most of common technologies have the problems of various steps, limited application range, overhigh energy consumption, long wall breaking time, low wall breaking efficiency, difficult realization of wall breaking industrialization and the like.

2. The technology for extracting grease by utilizing cavitation has the problems of low cavitation efficiency, high energy consumption and the like.

Disclosure of Invention

Aiming at the defects of the existing microalgae oil extraction device, the invention provides the microalgae oil extraction device based on hydraulic power and ultrasonic cavitation, which has high extraction efficiency.

The invention relates to a microalgae oil extraction device based on hydraulic power and ultrasonic cavitation, which adopts the following technical scheme:

a microalgae oil extraction device based on hydraulic power and ultrasonic cavitation comprises a stator, a rotor, a rotating shaft and an ultrasonic transducer, wherein the stator is a sealed cylinder, the ultrasonic transducer is distributed on the inner wall of the stator, a liquid discharge port and a liquid inlet are respectively arranged on two sides of the stator, the rotating shaft is installed in the stator, the rotor is positioned in the stator and installed on the rotating shaft, blades are distributed on the rotor, a cavity is formed in each blade, and cavitation through holes are distributed on two opposite sides of the cavity.

The ultrasonic transducer is connected with an ultrasonic generator, the frequency of the ultrasonic generator is 40-80 kHz, and the single-machine power is 1500-3000W.

The ultrasonic transducers are embedded into the inner wall of the stator in the axial direction and the circumferential direction at equal intervals, and each ring is 2-8 and 2-6 rings.

The liquid inlet and the liquid outlet are arranged diagonally to prevent short flow. The liquid inlet flow of the liquid inlet is 1.5-4.5 m³/h。

The rotating speed of the rotating shaft is 4000-4500 r/min.

The number of the rotors is 2-6 on the rotating shaft at equal intervals. The blades are distributed on the rotor at equal intervals along the circumferential direction and have 4-10 blades.

The inner diameter of the stator is 300-600 mm, the width is 200-500 mm, and the wall thickness is 15-40 mm. The reaction temperature in the stator is 50-80 DEG C

The blade is 50-200 mm long, 30-60 mm wide and 10-30 mm thick.

The axial line of the cavitation through hole is consistent with the rotation tangential direction of the rotor, but not consistent with the axial direction of the rotor.

The cavitation through hole is of a Venturi-shaped structure, an outlet and an inlet are respectively formed in two ends of the cavitation through hole, a throat part is formed in the middle of the cavitation through hole, the inner diameters of the outlet and the inlet are 1-6 mm, and the inner diameter of the throat part is 0.4-1 mm; the contraction angle is 35-50 degrees, and the expansion angle is 8-15 degrees.

The cavitation through holes are arranged in 4-10 rows and 3-10 rows of rectangular arrays on two sides of the inner cavity of the blade. The cavitation through holes at two sides of the hollow cavity in the blade are oppositely arranged and aligned pairwise. The surface roughness Ra of the inner wall of the cavitation through hole is smaller than 1.6 mm.

In order to ensure the formation of cavitation phenomenon and efficiently realize the process for extracting the oil from the microalgae, the structure and the process parameters are obtained by actual degradation experiments.

Mixing the raw material of the non-wall-broken microalgae cells with required liquid (water, methanol or ethanol and other liquid with better fluidity) under stirring to obtain a relatively dilute algae mud mixed solution. The algae mud mixed liquid is sent to the device of the invention, and is treated by hydrodynamic cavitation technology and ultrasonic cavitation to realize the rupture of microalgae cell walls, and is separated by a separation device to finally obtain the grease in the microalgae cells.

The device adopts a rotating hydrodynamic cavitation technology, innovatively adopts the high-speed rotation of the rotating shaft to drive the rotor, so that the Venturi-shaped cavitation through holes on the rotor efficiently generate cavitation bubbles, and the cavitation bubbles collapse and release huge energy when the static pressure is recovered. This energy is manifested as local hot spots up to 5000K, high pressures of 1000bar, with the generation of powerful shock waves and high-speed microjets (150 m/s). In addition, under the extreme conditions described above, water molecules can be hydrolyzed to generate hydroxyl radicals, hydrogen peroxide radicals, and hydrogen peroxide, which have strong oxidizing properties. The ultrasonic waves are coupled simultaneously under the action of the hydrodynamic cavitation effect, and are cooperated with efficient wall breaking, so that the energy generated during cavitation collapse is greatly enhanced, the generation of hydroxyl free radicals is promoted, and the wall breaking effect is finally improved. Therefore, the coupled use of the two can obtain the effect far higher than the sum of the wall breaking effect when used alone.

The invention has the following characteristics:

1. the device provided by the invention combines hydrodynamic cavitation and ultrasonic cavitation technologies to cooperate with microalgae grease extraction, so that the efficiency is far higher (can be improved by more than 3-4 times) than that of a method using hydrodynamic cavitation and ultrasonic cavitation alone, the efficiency is high, the processing capacity of the method is large, and continuous operation can be realized;

2. the cavitation through holes in the rotor of the device are in a Venturi structure, and the Venturi-shaped cavitation through holes at the two ends of the blades are aligned in pairs so as to realize two continuous cavitation processes on the premise of not changing the number of the blades, so that the cavitation effect is multiplied, and the cavitation efficiency is far higher than that of the traditional device;

3. the cavity of the blade provides a high-flow-rate low-pressure generating surface for the cavitation process, so that the turbulence effect is enhanced, and the cavitation effect is improved;

4. the surface roughness Ra of the inner wall of the rotor cavitation through hole of the device is less than 1.6mm, so that the cavitation primary effect is enhanced, and further the cavitation efficiency is improved (the cavitation efficiency is improved by about 20% compared with a cavitation through hole which is not subjected to finish machining);

5. the device adopts the symmetrical distribution of a plurality of rotors, each rotating disc is provided with an array Venturi hole, and the inner wall of the stator is provided with the ultrasonic transducer, so that the treatment efficiency of the hydrodynamic cavitation is greatly improved compared with the traditional cavitator;

6. the ultrasonic transducer in the device can be made into any shape according to different containers, and the device is built-in, so that the generated noise is small, and the energy attenuation is small;

7. the device has strong scalability, the sizes of the stator and the rotating disc type cavitation generator can be changed according to the processing requirement, and the requirement of larger extraction amount of the microalgae grease can be met by replacing a high-power device;

8. the device of the invention efficiently couples hydrodynamic cavitation and ultrasonic cavitation technologies, and the integrated equipment greatly simplifies the whole process flow;

9. in the running process of the device, the surfaces of the stator and the rotor are periodically cavitated and cleaned, so that the device has a self-cleaning function;

10. the device has the advantages of simple structure, strong adaptability, convenient operation, safety, reliability and convenient maintenance;

11. the device is not limited to extracting grease from microalgae, and is expected to have good treatment effect on other types of wall-broken extracted substances;

12. the structure and technological parameters of the device are obtained by actual degradation experiments.

Drawings

Fig. 1 is a schematic structural diagram of a microalgae oil extraction device based on hydraulic power and ultrasonic cavitation.

Fig. 2 is a schematic cross-sectional view of a stator and rotor of the present invention.

Fig. 3 is a schematic view of a rotor structure according to the present invention.

FIG. 4 is a flow chart of the process for extracting oil from microalgae according to the present invention.

In the figure: 1. the device comprises a liquid outlet, 2 parts of a sealing cover, 3 parts of a sealing end cover, 4 parts of a rotating shaft, 5 parts of an angular contact ball bearing, 6 parts of a mechanical seal, 7 parts of a wedge key, 8 parts of a stator end cover, 9 parts of a sealing gasket, 10 parts of a stator, 11 parts of an ultrasonic transducer, 12 parts of an ultrasonic generator, 13 parts of a cavitation through hole, 14 parts of a rotor, 15 parts of a liquid inlet, 16 parts of a cavity and 17 parts of a blade.

Detailed Description

The microalgae oil extraction device based on hydraulic power and ultrasonic cavitation, as shown in fig. 1 and 2, comprises a stator 10, a rotor 14, a rotating shaft 4, an ultrasonic transducer 11 and an ultrasonic generator 12.

The stator 10 is a hollow sealing cylinder, two ends of the stator are connected with a stator end cover 8 through bolts, and a sealing gasket 9 is arranged at the joint, so that a sealed cavity is formed inside the stator 10. The inner diameter of the stator is 300-600 mm, the width of the stator is 200-500 mm, and the wall thickness is 15-40 mm. The inner part of the stator end cover 8 is provided with an angular contact ball bearing 5, the outer part is provided with a sealing cover 2, the sealing cover 2 is connected with a sealing end cover 3, and a sealing ring 9 is arranged at the joint to form a sealing structure. An ultrasonic transducer 11 is mounted on the inner wall of the stator 10. Each ultrasonic transducer 11 is connected to an ultrasonic generator 12. The ultrasonic transducers are embedded into the inner wall of the stator in the axial direction and the circumferential direction at equal intervals, and each ring is 2-8 and 2-6 rings. The number of the ultrasonic generators 12 is 1-4, the frequency is 40-80 kHz, and the single-machine power is 1500-3000W. After the ultrasonic wave is coupled, the energy generated during the collapse of the cavitation can be greatly enhanced, the generation of hydroxyl free radicals is promoted, and the treatment effect is enhanced. The lower part of the left end cover of the stator 10 is provided with a liquid outlet 1, and the upper part of the right end cover is provided with a liquid inlet 15. The liquid inlet 15 and the liquid outlet 1 are arranged diagonally to prevent a short flow phenomenon. The liquid inlet 15 and the liquid outlet 1 are respectively connected with a control valve for controlling the flow. The liquid inlet flow at the liquid inlet 15 is 1.5-4.5 m³H is used as the reference value. Because the cavitation collapse continuously generates heat, the reaction temperature in the stator is 50-80 ℃.

The joint of the two ends of the rotating shaft 4 and the stator is provided with a mechanical seal 6 which is arranged outside the stator end cover 8 and inside the seal cover 2 so as to ensure the tightness of the device. The rotating shaft 4 is installed in the stator 10 through an angular contact ball bearing 5, one end of the rotating shaft extends out of the sealing cover 2, the rotating shaft is connected with a power device (motor) through a coupler and a speed increaser, the rotor 14 is driven to rotate in the stator 10, and the rotating speed of the rotating shaft 4 is 4000-4500 r/min. The rotor 14 is arranged in the cavity of the stator 10 and is fixedly arranged on the rotating shaft 4 through the wedge key 7. The rotors 14 are distributed on the rotating shaft 4 at equal intervals along the axial direction of the rotating shaft, and the number of the rotors is 2-6.

The rotor 14 is a multi-blade impeller structure, referring to fig. 3, blades 17 are distributed on the rotor 14, and 4-10 blades 17 are distributed on the rotor 14 at equal intervals along the circumferential direction. The blades 17 are of a hollow trapezoid structure with the cavity 16, and the cavity 16 provides a high-flow-speed low-pressure generating surface for the cavitation process, so that the turbulence effect and the cavitation effect are enhanced. The blade 17 has a length of 50 to 200mm, a width of 30 to 60mm, and a thickness of 10 to 30 mm. Cavitation through holes 13 are distributed in the blades 17 on two opposite sides of the cavity 16, and the axis of each cavitation through hole 13 is consistent with the rotation tangential direction of the rotor, but not consistent with the axial direction of the rotor 14. The cavitation through hole is of a Venturi structure, an outlet and an inlet are respectively arranged at two ends of the cavitation through hole, a throat part is arranged in the middle of the cavitation through hole, the inner diameters of the outlet and the inlet are 1-6 mm, and the inner diameter of the throat part is 0.4-1 mm; the contraction angle is 35-50 degrees, and the expansion angle is 8-15 degrees. The cavitation through holes 13 are arranged on the blades 17 in 4-10 rows and 3-10 rows in a rectangular array, so that cavitation bubbles can be generated and collapsed. The cavitation through holes 13 at two sides of the cavity 16 in the blade 17 are oppositely arranged and aligned with each other. When the rotor 14 rotates at a high speed, fluid enters from the large end of the venturi-shaped cavitation through hole 13 on one side, flows through the throat to generate cavitation, and then flows out from the small end. Then the fluid enters into the Venturi-shaped cavitation through hole on the other side to induce the cavitation phenomenon again. Therefore, the structure can realize two times of continuous cavitation processes on the premise of not changing the number of the blades, and the cavitation effect is multiplied. The surface roughness Ra of the inner wall of the cavitation through hole 13 is less than 1.6mm, so that the cavitation initial effect is enhanced, and further the cavitation efficiency is improved.

The structure and the parameters are obtained through an actual oil extraction experiment according to the characteristics of the microalgae oil extraction, and the optimal matching effect of the treatment effect is achieved.

The technological process for extracting oil from microalgae by using the device of the invention is shown in fig. 4, and the used facilities comprise a raw material tank, a stirrer, the device of the invention, a separation device and a collection tank. Adding microalgae cell raw materials and liquid medium (water, methanol or ethanol and other liquid with good fluidity) into the raw material tank, and stirring and mixing uniformly by a stirrer to obtain algae mud mixed solution.

The algae mud mixed liquid flows into the stator 10 from the liquid inlet 15, and the liquid inlet flow is 1.5-4.5 m³H is used as the reference value. The rotating shaft 4 drives the rotor 14 to rotate at a high speed of 4000-4500 r/min, so that the cavitation through holes 13 on the blades shear the fluid at a high speed, the local static pressure of the fluid is lower than the saturated vapor pressure, and the hydrodynamic cavitation phenomenon is induced. At the same time, an external ultrasonic sound generator12 the electricity is converted into a high-frequency alternating current signal matched with the ultrasonic transducer 11, and the high-frequency alternating current signal is transmitted to the ultrasonic transducer 11 embedded on the inner wall of the stator 10, and the ultrasonic transducer converts the electric energy into sound energy to generate high-frequency ultrasonic waves. The ultrasonic wave acts on the fluid to induce the ultrasonic cavitation phenomenon, thereby greatly increasing the number of cavitation bubbles generated by the hydraulic cavitation, enhancing the collapse intensity of the cavitation bubbles and improving the treatment efficiency. The extremely high temperature and high pressure condition generated by the cavitation phenomenon greatly improves the reaction rate of cell wall breaking. The coupling of the three treatment processes greatly improves the treatment effect and better achieves the purpose of breaking the cell walls of the microalgae cells. The treated liquid flows out through a liquid outlet 1 on a left stator end cover 8 and then enters a liquid inlet 15 for circular treatment until a satisfactory cell lysis result is obtained.

The cavitation bubbles generated by cavitation can generate instantaneous high temperature and high pressure and micro jet flow to repeatedly act on the cell surface when the cavitation bubbles are collapsed, so that the molecular structure of the cell surface is broken, organic molecules are broken, and the cell wall is broken and broken. The principle of ultrasonic wave and hydrodynamic cavitation is the same in the aspect of extracting grease, but the mode of cell disruption is slightly different, and the ultrasonic wave only plays a role in assisting in breaking cell walls.

The mixed liquid discharged from the stator 10 is separated into grease and fluid medium by a separating device, the grease is introduced into a collecting tank, and the fluid medium is reintroduced into a raw material tank for secondary utilization.

Examples are given below.

According to the invention, through an oil extraction experiment (the concentration of a microalgae-solvent mixture is 5 wt.%) on microalgae Nannochloropsis salina, under the optimal working condition and the structure (the parameters are that the inner diameter of a stator is 400mm, the width of the stator is 340mm, the wall thickness is 30mm, the blade length is 130mm, the width is 60mm, the thickness is 30mm, the inner diameters of an outlet and an inlet of a Venturi hole are 6mm, the inner diameter of a central throat part is 0.7mm, the contraction angle is 45 degrees, the expansion angle is 11 degrees, the Venturi holes on the blades are arranged in a 5 multiplied by 4 rectangular array, 4 ultrasonic transducers are arranged in each row, 6 rows are totally, 2 ultrasonic generators are provided, the single-machine power is 2000W, and the following conclusion is obtained:

extracting oil by autoclaving when energy input is 5000kJ/kgTreating for 1.5-30 minutes to obtain a lipid yield of about 16.2-66.5%; extracting the grease by an ultrasonic method, and treating for 2.8-55.6 minutes to obtain the lipid yield of about 5.4-26.9%; treating the lipid with a traditional Venturi hydrodynamic cavitation device for 5.9-118.1 minutes at a lipid yield of about 25.9-99.0%; the device of the invention has the rotation speed of 4500rpm and the flow rate of 2.6m³The reaction temperature is 75 ℃, the hydrodynamic cavitation and ultrasonic cavitation technology is coupled, the lipid yield of more than 99 percent can be realized within 5 minutes, and the process flow is efficient and environment-friendly in the process of extracting the oil from the microalgae and does not generate any pollutant.