阅读说明：本技术 一种超临界萃取分离釜及萃取系统和萃取方法 (Supercritical extraction separation kettle, extraction system and extraction method ) 是由 张雅萌 张雅晴 于 2020-06-12 设计创作，主要内容包括：本发明公开了一种超临界萃取分离釜及萃取系统和萃取方法。所述超临界萃取分离釜包括釜体、顶盖,以及釜体内由外向内依次套设的环形萃取层、环形多孔介质层、旋风分离器,这种环形层状结构一方面使得萃取剂以内旋的流动形式完成萃取,增大了萃取剂流动过程中同待萃取物之间的接触面积,大幅提高萃取产率；另一方面增加了萃取釜内部的空间利用率,避免了超临界萃取过程中常见的壁流问题；同时通过设计进气孔朝向以及设置弧形引流板,使得萃取分离釜内流场更加均匀、稳定。本发明的超临界萃取分离釜体具有萃取、降压与分离纯化三种功能,能够实现高品质、高效的生物活性成分萃取,以及萃取剂的循环重复利用。(The invention discloses a supercritical extraction separation kettle, an extraction system and an extraction method. The supercritical extraction separation kettle comprises a kettle body, a top cover, and an annular extraction layer, an annular porous medium layer and a cyclone separator which are sequentially sleeved in the kettle body from outside to inside, wherein the annular structure enables an extractant to be extracted in an internal spiral flowing mode, so that the contact area between the extractant and an extract to be extracted in the flowing process of the extractant is increased, and the extraction yield is greatly improved; on the other hand, the space utilization rate in the extraction kettle is increased, and the common wall flow problem in the supercritical extraction process is avoided; simultaneously, the flow field in the extraction separation kettle is more uniform and stable by designing the air inlet hole to face and arranging the arc-shaped drainage plate. The supercritical extraction separation kettle body has three functions of extraction, depressurization and separation and purification, and can realize high-quality and high-efficiency extraction of bioactive components and cyclic reuse of an extracting agent.)

1. A supercritical extraction separation kettle is characterized by comprising a kettle body, a top cover, an annular extraction layer, an annular porous medium layer and a cyclone separator, wherein the top of the kettle body is hermetically connected with the top cover; an annular extraction layer, an annular porous medium layer and a cyclone separator are arranged in the kettle body from outside to inside in sequence; placing the raw material to be extracted in the annular extraction layer, and extracting by supercritical fluid; the extracted mixed fluid is filtered by an annular porous medium layer and then enters a cyclone separator; the cyclone separator is provided with a hollow center shaft, the top end of the center shaft is communicated with the extractant outlet, under the centrifugal action of the cyclone separator, a liquid extraction product with high density flows out from the extraction product outlet at the bottom of the kettle body, and a gaseous extraction agent with low density enters the center shaft and is discharged from the extractant outlet at the top end.

2. The supercritical extraction separation kettle according to claim 1, wherein a guide vane with a circular spiral structure is arranged on the central shaft of the cyclone separator, and the opening direction of the supercritical fluid inlet hole is consistent with the spiral direction of the guide vane on the central shaft of the cyclone separator.

3. The supercritical extraction separation kettle according to claim 1, wherein the annular extraction layer is a cylindrical double-layer structure, an inner wall and an outer wall with holes form an annular cylindrical frame body with a rigid supporting function, and a metal filter screen with a material isolating function is arranged close to the inner sides of the inner wall and the outer wall; and a plurality of arc-shaped drainage plates are arranged in an annular space with a certain width enclosed by the metal filter screen, and the drainage direction of the arc-shaped drainage plates is consistent with the direction of the supercritical fluid air inlet.

4. The supercritical extraction separation kettle according to claim 3, wherein the kettle body side wall is provided with four equidistant supercritical fluid air inlets, and correspondingly, four equidistant arc-shaped flow guide plates are arranged in the annular extraction layer.

5. The supercritical extraction separation kettle according to claim 3, wherein the aperture of the hole on the annular cylindrical frame body of the annular extraction layer is 0.5-1 mm, and the mesh number of the metal filter screen is not less than 35 meshes; the annular multi-holeThe open porosity of the medium layer is more than 60 percent, and the specific surface area is 2.7m²A median pore diameter of 50 μm or less.

6. The supercritical extraction separation kettle of claim 1 wherein the annular porous media layer is porous ceramic.

7. The supercritical extraction separation kettle according to claim 1, wherein the cyclone separator is of a vertical cylindrical structure, wherein a guide vane of an annular spiral structure is arranged on a shaft from bottom to top; the outer wall of the cyclone separator is an annular metal frame with holes, and the annular metal frame is tightly attached to the annular porous medium layer; the cyclone separator is characterized in that a plurality of arc-shaped drainage plates are connected in the outer wall of the cyclone separator, and the opening direction of the arc-shaped drainage plates is consistent with the spiral direction of the guide vanes.

8. A supercritical carbon dioxide circulation extraction system comprises a supply tank, a heater, an infusion pump, a precooler, a supercritical extraction separation kettle, a cooler and a pipeline for connecting the supply tank, wherein the supercritical extraction separation kettle is as claimed in any one of claims 1 to 7, the supply tank is used for storing carbon dioxide liquid, the carbon dioxide liquid output from the supply tank is heated by the heater into supercritical carbon dioxide fluid, the supercritical carbon dioxide fluid enters the precooler for precooling under the action of the infusion pump, then enters the supercritical extraction separation kettle for carrying out active ingredient extraction on a material to be extracted in the kettle, an extraction product flows out of the bottom of the kettle body of the supercritical extraction separation kettle and is collected, and the separated supercritical carbon dioxide fluid is discharged from the top of the kettle body and is cooled and liquefied by the cooler and then circulates back to the supply tank.

9. The supercritical carbon dioxide circulation extraction system according to claim 8, wherein pressure sensors are respectively arranged on the pipeline from the heater to the liquid transfer pump, the pipeline from the precooler to the supercritical extraction separation kettle, and the pipeline from the cooler to the supply tank; a speed measuring instrument is arranged on a pipeline from the infusion pump to the precooler; and throttle valves are respectively arranged on a pipeline from the precooler to the supercritical extraction separation kettle, a pipeline connecting an extractant outlet of the supercritical extraction separation kettle and the cooler, and an extraction product outflow pipeline at the bottom of the supercritical extraction separation kettle.

10. A method for extracting active ingredients of biological materials at low temperature, which utilizes the supercritical carbon dioxide circulation extraction system of claim 8 to carry out the following operations:

1) placing the biological material powder to be extracted in an annular extraction layer in the supercritical extraction separation kettle, and closing the top cover of the supercritical extraction separation kettle;

2) starting the cooler, the heater and the precooler, starting the infusion pump, heating the carbon dioxide liquid output from the supply tank to the temperature and the pressure required by the supercritical fluid through the heater, then precooling the carbon dioxide liquid in the precooler through the infusion pump, controlling the supercritical carbon dioxide fluid to be in a required state, and continuously inputting the carbon dioxide liquid into the supercritical extraction separation kettle to extract the biological material powder;

3) the supercritical carbon dioxide fluid separated from the cyclone separator in the supercritical extraction separation kettle is cooled and liquefied by a cooler and then stored back into a supply tank;

4) continuously outputting carbon dioxide liquid from the supply tank, and repeating the steps 2) and 3) to perform extraction circulation until the required extraction product is obtained.

Technical Field

The invention relates to the technical field of supercritical extraction, in particular to a supercritical extraction separation kettle, an extraction system comprising the supercritical extraction separation kettle and an extraction method for extracting biological active ingredients at low temperature by using the extraction system.

Background

When the pressure and temperature of the fluid exceed the values corresponding to the critical points of the fluid, the fluid enters a supercritical state, the acting force between the fluid molecules is between the liquid and the gas molecules, and the fluid simultaneously shows high density similar to the liquid, good dissolving capacity and fluidity and low viscosity and good diffusivity similar to the gas, and can be used as a very ideal extracting agent. At present, more than 90% of supercritical extraction processes are carried out by using carbon dioxide, mainly because the carbon dioxide has lower critical pressure and temperature, and has the advantages of no toxicity, incombustibility, low cost, high purity, easy dispersion and low viscosity.

At present, the supercritical extraction apparatus widely used in practical production is realized by constructing a supercritical extraction cycle: the fluid can pass through the components such as the extraction kettle, the separator, the filter and the like in sequence in the extraction process to complete the relevant processes such as extraction, separation, self purification and the like of the extract to be extracted, and finally the fluid can enter the circulation to restore the initial state and enter the extraction kettle again to carry out the next extraction work. The currently used supercritical extraction circulation device mainly has the following problems: the extraction, separation and purification processes need more parts, and the actual circulation occupies a large space; secondly, the traditional hollow belt type extraction kettle has the problems that the space utilization rate in the kettle is low, and a direct-flow structure is easy to form wall flow to reduce the flow stability; and thirdly, the parts are redundant and the disassembly process is complicated. It is these problems that the extraction efficiency in actual production is greatly limited.

Disclosure of Invention

In order to solve the problems of space, efficiency and the like in the conventional supercritical extraction, the invention provides a novel supercritical extraction separation kettle structure, and a set of supercritical carbon dioxide circulation extraction system is constructed on the basis of the novel supercritical extraction separation kettle structure.

In a first aspect of the invention, a supercritical extraction separation kettle is provided, which comprises a kettle body, a top cover, an annular extraction layer, an annular porous medium layer and a cyclone separator, wherein the top of the kettle body is hermetically connected with the top cover, the center of the top cover is provided with an extractant outlet, the center of the bottom of the kettle body is provided with an extraction product outlet, and the middle part of the side wall of the kettle body is provided with a plurality of supercritical fluid air inlets; an annular extraction layer, an annular porous medium layer and a cyclone separator are arranged in the kettle body from outside to inside in sequence; placing the raw material to be extracted in the annular extraction layer, and extracting by supercritical fluid; the extracted mixed fluid is filtered by an annular porous medium layer and then enters a cyclone separator; the cyclone separator is provided with a hollow center shaft, the top end of the center shaft is communicated with the extractant outlet, under the centrifugal action of the cyclone separator, a liquid extraction product with high density flows out from the extraction product outlet at the bottom of the kettle body, and a gaseous extraction agent with low density enters the center shaft and is discharged from the extractant outlet at the top end.

Furthermore, the top cover and the kettle body are preferably made of carbon steel. In one embodiment of the invention, the inner diameter of the kettle body is 500mm, the wall thickness is 60mm, and the height of the kettle body is 500 mm. The kettle body is sealed with the top cover through a rubber ring and is fastened and connected through a bolt and nut assembly, so that the kettle body is sealed. A plurality of (such as 4) supercritical fluid air inlets are symmetrically arranged at the center of the side wall of the kettle body, and the aperture of each supercritical fluid air inlet is 12mm, for example. The guide vane with an annular spiral structure is arranged on the middle shaft of the cyclone separator, and preferably, the opening direction of the supercritical fluid air inlet is consistent with the spiral direction of the guide vane on the middle shaft of the cyclone separator. In one embodiment of the invention, the aperture of the extraction product outlet arranged at the bottom of the kettle body is 20 mm; the diameter of the hole of the extractant outlet arranged in the center of the top cover is 20 mm.

Furthermore, the annular extraction layer is of a cylindrical double-layer structure, an annular cylindrical frame body is formed by the inner wall and the outer wall with holes, the annular cylindrical frame body plays a role of rigid support, and the hole diameter of each hole is preferably 0.5-1 mm; metal filter screens are tightly attached to the inner sides of the inner wall and the outer wall to play a role of isolating materials, and the mesh number of the filter screens is preferably not less than 35 meshes; a plurality of arc-shaped drainage plates are arranged in an annular space with a certain width enclosed by the metal filter screen, the drainage direction of the arc-shaped drainage plates is consistent with the direction of the supercritical fluid air inlet holes, and the arc-shaped drainage plates are used for increasing the flow path of the supercritical fluid through the raw material powder to be extracted so as to improve the extraction efficiency.

The supercritical extraction separation kettle of the invention replaces the functions of a filter, a separator and a throttle valve in the traditional supercritical extraction circulating device by a single annular porous medium layer. In one embodiment of the invention, the thickness of the annular porous medium layer is 50mm, porous ceramic can be selected as a medium material, and the median pore size of the medium is required to be below 50 μm, so as to realize the filtering and purifying effect of the porous medium layer on the extracted mixed fluid. Preferably, the annular porous medium layer has an open porosity of 60% or more and a specific surface area of 2.7m or more²More than g, so as to ensure the smooth circulation of the supercritical fluid, and realize the function of turbulent flow decompression through the complex structure in the porous medium, thereby facilitating the mutual separation between the extracting agent and the extraction product.

In the supercritical extraction separation kettle, the cyclone separator adopts a vertical cylindrical structure, wherein a guide vane is arranged on a shaft, the guide vane preferably adopts a bottom-up annular spiral structure, the height of the vane is 20-40 mm, and the distance between the vanes is 40-50 mm; the outer wall of the cyclone separator is preferably an annular metal frame with holes, the annular metal frame is tightly attached to the inner wall of the annular porous medium layer to prevent wall flow, a plurality of (such as 4) arc-shaped flow guide plates are connected in the outer wall of the cyclone separator, the arrangement direction of the arc-shaped flow guide plates is consistent with the spiral direction of guide vanes on a central shaft of the cyclone separator, and the internal space of the device is fully utilized to reduce the partial load of the cyclone. In the actual production, the density difference between the extractant and the extraction product is utilized, the liquid extraction product with higher density is rotated to the outer wall of the central shaft of the cyclone separator through the centrifugal action, flows downwards along the guide vanes through the gravity action, is discharged through the extraction product outlet and stored in a related container, the gaseous extractant with lower density is continuously involved into the lower part of the cyclone separator, passes through the hollow central shaft from the lower part of the central shaft, and is finally discharged out of the extraction separation kettle from the extractant outlet above the top cover of the kettle body.

In the supercritical extraction separation kettle, preferably, the annular extraction layer and the cyclone separator are both provided with the arc-shaped drainage plates, and the supercritical fluid entering from the supercritical fluid inlet hole is sequentially drained by the arc-shaped drainage plates in the annular extraction layer and the cyclone separator so as to ensure the smooth flow of the supercritical fluid in the extraction separation kettle.

In a second aspect of the invention, a set of supercritical carbon dioxide circulation extraction system is constructed by utilizing the supercritical extraction separation kettle, and a method for extracting plant or microorganism active substances at low temperature is provided.

The supercritical carbon dioxide circulation extraction system comprises a supply tank, a heater, an infusion pump, a precooler, a supercritical extraction separation kettle, a cooler and a pipeline for connecting the supply tank and the heater, wherein the supply tank is used for storing carbon dioxide liquid, the carbon dioxide liquid output from the supply tank is heated by the heater into supercritical carbon dioxide fluid, the supercritical carbon dioxide fluid enters the precooler for precooling under the action of the infusion pump and then enters the supercritical extraction separation kettle to extract active ingredients of materials to be extracted in the kettle, an extraction product flows out from the bottom of the kettle body and is collected, and the separated supercritical carbon dioxide fluid is discharged from the top of the kettle body and is cooled and liquefied by the cooler and then is circulated back to the supply tank.

Furthermore, pressure sensors are arranged on pipelines from the heater to the infusion pump, pipelines from the precooler to the supercritical extraction separation kettle, and pipelines from the cooler to the supply tank, and are used for monitoring the pressure of fluid in each pipeline. A velocimeter is arranged on a pipeline from the infusion pump to the precooler to monitor the flow rate of the supercritical carbon dioxide fluid.

Furthermore, a throttle valve is arranged on a pipeline from the precooler to the supercritical extraction separation kettle to control the flow rate of the supercritical carbon dioxide entering the supercritical extraction separation kettle; a throttle valve is also arranged on a pipeline connecting an extractant outlet of the supercritical extraction separation kettle and the cooler so as to control the flow rate of the discharged supercritical carbon dioxide fluid; a throttle valve is also arranged on the extraction product outlet pipeline at the bottom of the supercritical extraction separation kettle.

In the supercritical carbon dioxide circulation extraction system, carbon dioxide liquid stored in a supply tank is output to a heater, the carbon dioxide liquid is heated to the temperature and pressure (50 ℃ and 10-11 MPa) required by extraction through the heater to obtain supercritical carbon dioxide fluid, then the supercritical carbon dioxide fluid enters a precooler for precooling under the action of a liquid delivery pump, the supercritical carbon dioxide fluid state at the outlet of the precooler is controlled to be 43.5-45.2 ℃ and 10.0-10.5 MPa, and the supercritical carbon dioxide fluid is sent into a supercritical extraction separation kettle for active ingredient extraction; under the action of the cyclone separator in the extraction separation kettle, the extraction product flows out from the bottom of the kettle, and the separated supercritical carbon dioxide fluid is discharged from the top of the kettle, enters a cooler for cooling and liquefaction, reaches the required state (-20 ℃, 2.16MPa), and is stored back into the supply tank.

The working process of performing low-temperature extraction on the active ingredients of the biological material by utilizing the supercritical carbon dioxide circulating extraction system comprises the following steps:

1) placing the pretreated animal and plant, microorganism or other biological material powder to be extracted into an annular extraction layer in the extraction separation kettle, and closing the top cover of the extraction separation kettle;

2) starting the cooler, the heater and the precooler, starting the infusion pump, heating the carbon dioxide liquid output from the supply tank to the temperature and pressure (50 ℃, 10-11 MPa) required by the supercritical fluid through the heater, then entering the precooler through the infusion pump for precooling, controlling the supercritical carbon dioxide fluid to be in a required state (43.5-45.2 ℃, 10.0-10.5 MPa), and continuously inputting the supercritical carbon dioxide fluid into the extraction separation kettle for extraction;

3) cooling and liquefying the supercritical carbon dioxide fluid separated from the cyclone separator in the extraction separation kettle by a cooler to reach the required state (-20 ℃, 2.16MPa), and storing the liquefied supercritical carbon dioxide fluid back to the supply tank;

4) continuously outputting carbon dioxide liquid from the supply tank, and repeating the steps 2) and 3) to perform extraction circulation until the required extraction product is obtained.

In the step 2), the carbon dioxide liquid is firstly heated by the heater to the temperature and pressure (50 ℃ and 10-11 MPa) required by the supercritical fluid, and then is pumped into the precooler by the infusion pump for precooling so as to avoid the phenomenon of 'cavitation' which causes the pressure increase at the inlet of the extraction separation kettle, and the supercritical fluid state at the outlet of the precooler is controlled to be 43.5-45.2 ℃ and 10.0-10.5 MPa so as to obtain higher extraction purity and extraction efficiency.

Preferably, in the step 2), a velocimeter is arranged at the outlet of the infusion pump, the power of the infusion pump is adjusted, and the reading of the velocimeter is controlled within the range of 2-4 m/s.

The invention has the advantages that:

1) compared with an extractant input mode from bottom to top in a traditional extraction kettle, the annular layered structure of the extraction separation kettle enables the extractant to be extracted in an internal rotation flowing mode, the contact area between the extractant and an extract to be extracted in the flowing process is increased, and the extraction yield is greatly improved;

2) the annular layered structure design of the extraction separation kettle increases the space utilization rate in the extraction kettle, avoids the common wall flow problem in the supercritical extraction process, and simultaneously enables the flow field in the extraction separation kettle to be more uniform and stable by designing the direction of the air inlet and arranging the arc-shaped drainage plate;

3) according to the invention, 3 functions of extraction, depressurization, separation and purification are simultaneously realized through one extraction separation kettle body, and the functions can be realized only by respectively arranging three parts in the traditional circulation, so that the occupied space of equipment is saved and the construction cost of the circulation is reduced compared with the traditional circulation;

4) the unique combination of the supercritical carbon dioxide extraction temperature and pressure and the design of the unique extraction separation kettle structure realize high-quality and high-efficiency extraction of active ingredients of animals, plants and microorganisms;

5) the recycling of the carbon dioxide extracting agent is realized by constructing extraction circulation, and the extraction capacity is greatly improved (the extraction efficiency is improved by about 35%);

drawings

FIG. 1 is a schematic diagram of the supercritical carbon dioxide extraction system according to an embodiment of the present invention;

FIG. 2 is a longitudinal sectional view (front view) of an extraction separation tank in an embodiment of the present invention;

FIG. 3 is a cross-sectional view (plan view) of an extraction separation tank in an embodiment of the present invention;

in the figure: 1 is an extraction separation kettle, 2 is a first throttling valve, 3 is a second throttling valve, 4 is a cooler, 51-position first pressure sensors, 52 is a second pressure sensor, 53 is a third pressure sensor, 6 is a supply tank, 7 is a heater, 8 is an infusion pump, 9 is a velocimeter, 10 is a precooler, 11 is a third throttling valve, 1-1 is a top cover, 1-2 is a kettle body, 1-3 is an annular extraction layer, 1-4 is an annular porous medium layer, 1-5 is a cyclone separator, 1-6 is a bolt nut component, 1-1-1 is an extractant outlet, 1-2-1 is a supercritical fluid air inlet, 1-2-2 is an extraction product outlet, 1-3-1 is an annular cylindrical frame body, 1-3-2 is an arc-shaped drainage plate, 1-3-3 is a metal filter screen, 1-5-1 is the outer wall of the cyclone separator, 1-5-2 is the arc-shaped flow guide plate of the cyclone separator, 1-5-3 is the middle shaft of the cyclone separator, and 1-5-4 is the guide vane.

Detailed Description

The technical solution of the present invention is further described in detail by specific embodiments with reference to the accompanying drawings.

As shown in fig. 1, the supercritical carbon dioxide cyclic extraction system comprises: the extraction separation kettle 1, a cooler 4, a supply tank 6, a heater 7, a liquid conveying pump 8 and a precooler 10. Outputting the carbon dioxide liquid stored in the supply tank 6 to a heater 7, and heating the carbon dioxide liquid to the temperature and pressure (50 ℃, 10-11 MPa) required by extraction through the heater 7 to obtain supercritical carbon dioxide fluid; the supercritical carbon dioxide fluid enters a precooler 10 for precooling under the action of an infusion pump 8, and the state of the supercritical carbon dioxide fluid at the outlet of the precooler 10 is controlled to be 43.5-45.2 ℃ and 10.0-10.5 MPa; the supercritical carbon dioxide fluid enters from the side surface of the extraction separation kettle 1 through a pipeline provided with a third throttle valve 11, and active ingredients are extracted from the materials in the kettle; under the action of a cyclone separator in the extraction separation kettle 1, an extraction product flows out from the bottom of the extraction separation kettle 1, and a first throttle valve 2 is arranged on a flow outlet pipeline to control the flow speed; the separated supercritical carbon dioxide fluid is discharged from the top of the extraction separation kettle 1, is depressurized by a second throttling valve 3, enters a cooler 4 for cooling and liquefaction, reaches the required state (-20 ℃, 2.16MPa), and is stored back into a supply tank 6. A first pressure sensor 51 is arranged on a pipeline from the cooler 4 to the supply tank 6, a second pressure sensor 52 is arranged on a pipeline from the heater 7 to the infusion pump 8, and a third pressure sensor 53 is arranged on a pipeline from the precooler 10 to the extraction separation kettle 1, and is respectively used for monitoring the pressure of fluid in each pipeline. The power of the infusion pump 8 is monitored by a tachometer 9 arranged on the line between the infusion pump 8 and the precooler 10.

The structure of the extraction separation kettle 1 in the extraction system is shown in fig. 2 and fig. 3, and comprises a top cover 1-1, a kettle body 1-2, an annular extraction layer 1-3, an annular porous medium layer 1-4 and a cyclone separator 1-5, wherein the annular extraction layer 1-3, the annular porous medium layer 1-4 and the cyclone separator 1-5 are sequentially sleeved in the kettle body 1-2 from outside to inside; the annular extraction layer 1-3 is an annular space with a certain width enclosed by an annular cylindrical frame body 1-3-1 with holes on the inner wall and the outer wall and a metal filter screen 1-3-3 tightly attached to the inner sides of the two wall surfaces, and four arc-shaped drainage plates 1-3-2 are arranged in the space at equal intervals; an extractant outlet 1-1-1 is arranged in the center of the top cover 1-1, and an extraction product outlet 1-2-2 is arranged at the bottom of the kettle body 1-2; a related vessel can be connected below the extraction product outlet 1-2-2 for collecting the extraction product; the side wall of the kettle body 1-2 is provided with four supercritical fluid air inlets 1-2-1 which respectively correspond to the positions of four arc-shaped drainage plates 1-3-2 in the annular extraction layer 1-3.

The top cover 1-1 and the kettle body 1-2 are made of Q245R carbon steel, the inner diameter of the kettle body 1-2 is 500mm, the wall thickness is 60mm, and the height of the kettle body is 500 mm. The kettle body 1-2 and the top cover 1-1 are sealed through polyurethane rubber rings and are tightly connected through bolt and nut assemblies 1-6, so that the kettle body is sealed. 4 supercritical fluid air inlets 1-2-1 are formed in the middle of the side wall of the kettle body 1-2, the aperture of the supercritical fluid air inlet 1-2-1 is 12mm, the opening direction of the supercritical fluid air inlet is consistent with the internal rotation direction of the central shaft 1-5-3 of the cyclone separator (namely the spiral direction of the guide vane 1-5-4), and the supercritical fluid entering from the supercritical fluid air inlet 1-2-1 is sequentially guided by the arc-shaped guide plates 1-3-2 and 1-5-2 in the annular extraction layer 1-3 and the cyclone separator 1-5, so that the supercritical fluid in the extraction separation kettle can flow smoothly. The aperture of an extraction product outlet 1-2-2 arranged at the bottom of the kettle body 1-2 is 20 mm; the aperture of an extractant outlet 1-1-1 arranged in the center of the top cover 1-1 is 20 mm.

Different from the traditional cylindrical extraction frame body, the invention adopts an annular extraction layered structure. The annular extraction layers 1-3 adopt a double-layer structure, and the width of the inner layer is 50mm (namely the distance between the outer wall and the inner wall of the annular cylinder with the holes in the radial direction). The metal filter screens 1-3-3 positioned at the inner sides of the inner wall surface and the outer wall surface of the annular cylindrical frame body 1-3-1 play a role of isolating materials, and the mesh number of the filter screens is not less than 35 meshes; the inner wall and the outer wall of the annular cylinder with the holes play a role of rigid support, and the aperture of the holes is 0.5-1 mm; the inlet flow direction of the arc-shaped flow guide plate 1-3-2 arranged in the annular extraction layer 1-3 is consistent with the direction of the supercritical fluid air inlet 1-2-1, and the flow guide plate is used for increasing the flow path of the supercritical fluid passing through the raw material powder to be extracted so as to improve the extraction efficiency.

The invention replaces the functions of a filter, a separator and a throttle valve in the traditional supercritical extraction circulation by the single annular porous medium layer 1-4. The thickness of the annular porous medium layer is 1-4 mm, porous ceramic can be selected as a medium material, and the median pore size of the medium is required to be below 50 μm, so that the filtering and purifying effects of the porous medium layer on the extracted mixed fluid are realized. In addition, the open porosity of the annular porous medium layers 1-4 is required to be more than 60%, and the specific surface area is required to be 2.7m²More than g, so as to ensure the smooth circulation of the supercritical fluid, and realize the function of turbulent flow decompression through the complex structure in the porous medium, thereby facilitating the mutual separation between the extracting agent and the extraction product.

The cyclone separator 1-5 adopts a vertical cylindrical structure, the outer wall 1-5-1 of the cyclone separator is an annular metal frame with holes, and the annular metal frame is tightly attached to the inner wall of the porous medium layer 1-4 so as to prevent the wall flow phenomenon; 4 arc-shaped flow guide plates 1-5-2 which are equally spaced are connected in the outer wall 1-5-1 of the cyclone separator, the opening direction of the flow guide plates is consistent with the spiral direction of the flow guide blades 1-5-4 on the center shaft 1-5-3 of the cyclone separator, and the internal space of the equipment is fully utilized to reduce the load of the cyclone; the guide vanes 1-5-4 are of a bottom-up annular spiral structure, the height of the vanes is 20-40 mm, and the spacing between the vanes is 40-50 mm; the central shaft 1-5-3 of the cyclone separator is of a hollow structure, in the actual production, the liquid extraction product with higher density is rotated to the outer wall of the central shaft 1-5-3 of the cyclone separator by utilizing the density difference between the extraction agent and the extraction product, flows downwards along the guide vanes 1-5-4 under the action of gravity, is discharged through an extraction product outlet 1-2-2 and stored in a related container, the gaseous extraction agent with lower density is continuously involved into the lower part of the cyclone separator, passes through the hollow central shaft from the lower part of the central shaft 1-5-3 of the cyclone separator, and is finally discharged out of the extraction separation kettle from an outlet 1-1-1 above a kettle top cover 1-1.

The supercritical carbon dioxide circulation extraction system constructed by the extraction separation kettle is used for extracting effective biological components in herbaceous plants at low temperature.

The following description of the extraction procedure of herbal extracts is given with the example of wormwood:

1) placing a proper amount of dry wormwood in a ball mill, grinding for 3 hours at a low speed under a cooling condition, controlling the temperature in the grinding process not to exceed 35 ℃, and enabling the particle size of wormwood powder after grinding to be 0.5-0.7 mm;

2) placing the ground wormwood powder into an annular extraction layer 1-3 of an extraction separation kettle 1, closing a top cover 1-1 of the extraction separation kettle, screwing a sealing nut, and starting a supercritical carbon dioxide extraction cycle;

3) adjusting the power of the infusion pump 8, controlling the flow rate of an extracting agent of the supercritical carbon dioxide extraction circulation to be 2-4 m/s, controlling the state of the supercritical carbon dioxide input into the extraction separation kettle 1 to be 43.5-45.2 ℃ and 10.0-10.5 MPa through the heater 7 and the precooler 10, and controlling the extraction time of the wormwood powder to be 75-87 minutes (not more than 90 minutes);

4) and (3) closing the infusion pump 8 after extraction is finished, closing the second throttling valve 3 and the third throttling valve 11, opening the first throttling valve 2, taking out the liquid in the collector at the bottom of the extraction separation kettle 1, standing for 10 minutes, and obtaining the required liquid oily wormwood extract after the residual carbon dioxide is vaporized and separated.

The present invention is not limited to the above-described preferred embodiments, and those skilled in the art will appreciate that various changes, substitutions, and alterations are possible in the shapes and configurations of the embodiments described without departing from the principle and spirit of the invention. Therefore, the invention should not be limited to the disclosure of the drawings and the embodiments, and the scope of the invention is defined by the claims.