A supercritical fluid fluidized continuous extraction and separation system and process

Abstract

The present invention discloses a supercritical fluid fluidized continuous extraction and separation system and process, which can be widely used in the fields of chemical industry, food industry, pharmaceutical industry, etc., and has broad prospects. The system consists of a supercritical fluidized continuous extraction system, a pressure reduction separation system, a supercritical working medium refrigeration system, and a supercritical fluid circulation and pressurization system. Among them, the supercritical fluidized continuous extraction system includes a material feeding subsystem, a material fluidized extraction subsystem and an extract residue separation subsystem. The present invention adopts a fluidized extraction process, realizes continuous extraction through a designed supercritical fluid circulation system, and realizes the recycling of supercritical fluid through other supporting equipment and systems, which reduces the failure rate of the device, improves the feeding efficiency, reduces energy consumption, and improves the resource utilization efficiency.

Description

Technical Field

[0001] The present invention relates to the field of modern separation technology and mechanical equipment, and in particular to a supercritical fluid fluidized continuous extraction separation system and process. Background Art 2. Technical Background

[0003] Separation technology plays an important role in modern industry. Supercritical fluid extraction, as an emerging separation technology, has many advantages over traditional separation technologies. With the improvement of material living standards, the demand for natural foods, medicines, spices, etc. is becoming increasingly strong. Supercritical fluid extraction technology has broad prospects. However, most current supercritical fluid extraction equipment for solid-phase materials is mostly intermittent operation, and the extractor is repeatedly opened and closed for material filling and unloading. This leads to large energy loss, high operating costs, and shortened equipment life. Continuous extraction is impossible, which reduces the overall extraction efficiency. In addition, the supercritical fluid in the cyclone extractor must be emptied every time the material is loaded and unloaded, resulting in a waste of resources and increased costs.

[0004] On August 23, 2019, the patent with the authorization announcement number CN110152350B was granted, and the invention name is "A Subcritical Fluid Continuous Isobaric Extraction and Separation Device System and Extraction and Separation Process." The extraction and separation process implemented by this device system is that after the systematic process operation, the extracted subcritical fluid or supercritical fluid in the silo enters the corresponding separation subsystem to begin separation, and the discharge valve is periodically opened to discharge the extract separated by the separation subsystem. However, the device silo charging / unloading requires the corresponding charging / unloading valve to be continuously opened, which poses a safety issue. It also requires manual loading, which is labor-intensive and has a complex structure. It cannot be considered a truly continuous extraction system, but rather a semi-continuous extraction system.

[0005] On September 17, 2019, a patent with announcement number CN110237561A and patent name "A supercritical fluid continuous extraction and separation device system and extraction and separation process" was authorized, disclosing a supercritical fluid extraction device. The invention proposes a new supercritical continuous extraction method based on a magazine structure, which realizes the continuous supercritical extraction. However, the extraction process of this device belongs to fixed bed extraction. During multi-extractor extraction, bias flow will occur, so that the extraction effect does not achieve the expected results, and it is not suitable for large and medium-sized supercritical extraction processes. In addition, the loading and unloading of the magazine requires manual work, and the work intensity is relatively high. This supercritical extraction system cannot be considered truly continuous, but is also a semi-continuous extraction system. Summary of the Invention

[0006] In order to solve the technical problems existing in the background technology, the present invention aims to overcome the problems existing in the existing supercritical fluid extraction and separation devices for solid phase materials and provide a new supercritical fluid fluidized continuous extraction and separation system and process.

[0007] The technical solution adopted in the present invention is as follows:

[0008] The present invention proposes a supercritical fluid fluidized continuous extraction and separation system, which is composed of a supercritical fluidized continuous extraction system, a pressure reduction separation system, a supercritical working medium refrigeration system, and a supercritical fluid circulation and pressurization system. The supercritical fluidized continuous extraction system includes a material feeding subsystem, a material fluidized extraction subsystem, and a residue separation subsystem; the material feeding subsystem is connected to the material fluidized extraction subsystem, and the material feeding subsystem relies on the material gravity and the gaseous extractant from the original gas cylinder to feed the extracted material into the material fluidized extraction subsystem for the first time; the material fluidized extraction subsystem is composed of one or more parallel cyclone extractors and a circulation pump, and the cyclone extractor is provided with a supercritical fluid inlet, a material outlet, and an overflow port; the supercritical fluid output by the supercritical fluid circulation and pressurization system enters the cyclone extractor tangentially from the supercritical fluid inlet, forms a fluidized cyclone with the extracted material, and promotes the supercritical fluid and the extracted material to flow smoothly. Shearing and particle impact crushing are generated to accelerate extraction; the supercritical fluid carrying the solute is discharged from the overflow port and then pumped back into the cyclone extractor through a circulation pump until the supercritical fluid reaches a saturated state and then enters the pressure reduction separation system from the supercritical fluid outlet; the raffinate in the cyclone extractor is discharged from the material outlet and enters the raffinate separation subsystem; the supercritical working fluid refrigeration system cools and liquefies the extractant and then sends it to the supercritical fluid circulation and pressurization system; the supercritical fluid circulation and pressurization system cools and pressurizes the gaseous extraction medium from the pressure reduction separation system to become a supercritical fluid and sends it back to the cyclone extractor; the gaseous extraction medium of the pressure reduction separation system sends the extracted material in the material pressure tank into the cyclone extractor, completing the re-feeding process.

[0009] As a further technical solution, the pressure reduction separation system includes a No. 1 intermediate heat exchanger, a No. 2 intermediate heat exchanger, a pressure reducing kettle and a separation kettle; the hot flow side inlet of the No. 1 intermediate heat exchanger is connected to the overflow port of the cyclone extractor, and the hot flow side outlet of the No. 1 intermediate heat exchanger is connected to the pressure reducing kettle through a first-level pressure regulating valve; the outlet of the pressure reducing kettle is connected to the hot flow side inlet of the No. 2 intermediate heat exchanger, and the hot flow side outlet of the No. 2 intermediate heat exchanger is connected to the separation kettle through a second-level pressure regulating valve; the gaseous extraction medium outlet of the separation kettle is also connected to the material feeding subsystem and the supercritical fluid circulation and pressurization system; the extract and the supercritical fluid coming out of the overflow port of one or more parallel cyclone extractors are connected. The supercritical fluid enters the hot-stream inlet of the No. 1 intermediate heat exchanger and undergoes a first heat exchange with the condensed, liquefied, and pressurized supercritical fluid on the cold-stream side of the No. 1 intermediate heat exchanger. The hot-stream outlet of the No. 1 intermediate heat exchanger is connected to a pressure-reducing kettle via a primary pressure-regulating valve. The extract and supercritical fluid exiting the pressure-reducing kettle enter the hot-stream inlet of the No. 2 intermediate heat exchanger and undergo a second heat exchange with the condensed, liquefied, and pressurized supercritical fluid on the cold-stream side of the No. 2 intermediate heat exchanger. The hot-stream outlet of the No. 2 intermediate heat exchanger is connected to a separation kettle via a secondary pressure-regulating valve. At this point, the supercritical fluid changes phase to a gaseous state, releasing the extracted solutes for storage in the separation kettle in gaseous form. A portion of the gaseous extraction medium is used to transport materials within the material pressurization tank, and a portion flows back into the supercritical fluid circulation and pressurization system.

[0010] As a further technical solution, the material feeding subsystem comprises a material tank and a material pressurizing tank. A drain valve is provided at the top of the material tank, and a balancing valve is connected between the material tank and the material pressurizing tank. The discharge port of the material pressurizing tank is connected to the cyclone extractor. The material pressurizing tank is also connected to the gaseous extraction medium outlet of the separation kettle. A drain valve is provided at the top of the material tank. After each loading operation, the material tank can be emptied using the gaseous extraction medium remaining in the slag storage tank. Alternatively, the material tank can be emptied using the gaseous extraction medium in the material pressurizing tank through the balancing valve between the material tank and the material pressurizing tank, and the material pressurizing tank can be fed through the discharge valve. The gaseous extraction medium from the separation kettle delivers the extracted material in the material pressurizing tank to the cyclone extractor, completing one feeding process.

[0011] As a further technical solution, the supercritical fluid circulation and pressurization system consists of a buffer tank, a circulation heater, a booster pump, a No. 3 intermediate heat exchanger, and a supercritical working fluid refrigeration system; the buffer tank is connected to the supercritical working fluid refrigeration system, and the supercritical working fluid refrigeration system changes the gaseous extractant into a liquid state; after being pressurized to the pressure required by the extraction process by the booster pump, it changes into the supercritical state required by the extraction process through the No. 3 intermediate heat exchanger and the circulation heater, and enters the supercritical fluidization extraction subsystem.

[0012] As a further technical solution, the supercritical working medium refrigeration system is composed of an extractant gas cylinder, a filling valve, and a refrigeration unit; the extractant in the extractant gas cylinder enters the refrigeration unit through the filling valve for cooling and liquefaction, and then enters the supercritical fluid circulation and pressurization system.

[0013] As a further technical solution, the raffinate separation subsystem consists of a slag storage tank and a gas-solid separation tank. The gas outlet at the upper end of the gas-solid separation tank enters the system pipeline of the supercritical fluid circulation and pressurization system through a gate valve. The raffinate outlet in the gas-solid separation tank is connected to the slag storage tank through a discharge valve. The raffinate is blown into the gas-solid separation tank by the gaseous extraction medium from the separation kettle.

[0014] As a further technical solution, a filter and a backwash device are installed at the overflow port of the cyclone extractor; the filter prevents the extracted material from entering the pressure reduction separation system, ensuring the purity of the extract; at the same time, in order to prevent the cyclone extractor filter from clogging, a backwash device is designed in the system to improve the efficiency and continuity of the supercritical fluid continuous extraction and separation process.

[0015] In a second aspect, the present invention further provides a separation process based on the supercritical fluid fluidized continuous extraction and separation system, as follows:

[0016] The first time the material is added is after the system is emptied. The material enters the material pressurizing tank by gravity. The gaseous extractant from the original gas cylinder blows the extracted material in the material pressurizing tank to the cyclone extractor. When the extracted material reaches a certain amount, the outlet valve of the material pressurizing tank is closed, and the supercritical fluid circulation and pressurization system is opened. The supercritical fluid output by the supercritical fluid circulation and pressurization system enters the cyclone extractor tangentially to form a fluidized mixture with the extracted material for extraction. The supercritical fluid carrying the extracted solute flows out from the overflow port at the upper end of the cyclone extractor and returns to the cyclone extractor through the circulation pump until the supercritical extractant After reaching or approaching saturation, the circulation pump is closed and the fluid enters the pressure reduction separation system from the overflow port at the upper end of the cyclone extractor. The pressure reduction separation system changes the supercritical fluid into a gaseous state, separates the extracted solute, and stores it in the separation kettle in liquid form. Part of the gaseous extraction medium is used to transport the material in the material pressure tank, and part of it flows back to the supercritical fluid circulation pressurization system; the raffinate enters the raffinate separation subsystem from the material outlet of the cyclone extractor for separation; during the entire process, the material loading is to transport the material in the material pressure tank through the gaseous extractant separated by the pressure reduction separation system.

[0017] Compared with the existing supercritical fluid extraction separation technology, the present invention has the following advantages:

[0018] 1. The present invention adopts a fluidized extraction process. The supercritical fluid enters the cyclone extractor tangentially, forming a fluidized cyclone with the extracted material. This promotes shearing of the supercritical fluid and the extracted material, and particle impact and crushing, achieving full mixing, thereby accelerating extraction. The fluidized cyclone extractor increases the contact area between the supercritical fluid and the extracted material, improving the extraction efficiency, and the supercritical fluid is recycled through other supporting equipment and systems.

[0019] 2. The material loading and unloading of the present invention uses the recycled extraction medium as power, and realizes automatic material loading and unloading through the pressure balance between each operating unit, avoiding the disadvantages of repeated opening and closing when loading and unloading materials in traditional extractors, improving feeding efficiency, reducing the failure rate of the device, and having a high degree of automation; specifically, the loading of the extracted material is powered by the supercritical fluid recycled in the system. The first loading of the material is after the system is emptied, the discharge valve of the material tank is opened, and the material enters the material pressurizing tank by gravity, and the gaseous extractant from the original gas cylinder blows the extracted material in the material pressurizing tank into the cyclone extractor through the outlet valve and the feed valve; the subsequent material loading is to transport the material in the material pressurizing tank through the gaseous extractant in the separation kettle; the gaseous extractant from the separation kettle blows the extracted material in the material pressurizing tank into the cyclone extractor, completing the re-feeding process.

[0020] 3. The pressure reduction and separation system of the present invention recycles the heat before the step-by-step throttling and pressure reduction by utilizing two intermediate heat exchangers. At the same time, a third intermediate heat exchanger is added after the compressor of the refrigeration unit to further utilize the waste heat of the refrigeration unit, saving heat loss, enabling heat to be recovered and reused, and reducing heat waste in the system.

[0021] 4. The system of the present invention is designed with a backwash function to improve the continuity of the extraction process. In addition, the material fluidization extraction subsystem realizes a continuous extraction cycle of the material, automatically mixes and separates the material and the supercritical fluid, improves the overall extraction efficiency of the process, and overcomes the problem of insufficient contact between the material and the supercritical fluid and incomplete extraction in traditional cyclone extractors. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 , is a process flow chart of a supercritical fluid fluidized continuous extraction and separation system of the present invention

[0023] In the picture:

[0024] 1. Supercritical working fluid refrigeration system; 1-1. Extractant gas cylinder, 1-2. Filling valve, 1-3. Refrigeration unit;

[0025] 2. Supercritical fluid circulation and pressurization system; 2-1. Drain valve, 2-2. Buffer tank, 2-3. Check valve, 2-4. Stop valve, 2-5. Booster pump, 2-6. Check valve, 2-7. No. 3 intermediate heat exchanger, 2-8. Circulation heater;

[0026] 3. Material fluidization extraction subsystem; 3-1. Stop valve, 3-2-1. Feed valve, 3-2-2. Feed valve, 3-2-N. Feed valve, 3-3-1. Cyclone extractor, 3-3-2. Cyclone extractor, 3-3-N. Cyclone extractor, 3-4. Pulse valve, 3-5-1. Stop valve, 3-5-2. Stop valve, 3-5-N. Stop valve, 3-6-1. Stop valve, 3-6-2. Stop valve, 3-6-N. Stop valve, 3-7-1. Check valve, 3-7-2. Check valve, 3-7-N. Check valve, 3-8-1. Circulation pump, 3-8-2. Circulation pump, 3-8-N. Circulation pump, 3-9-1. Feed valve, 3-9-2. Feed valve, 3-9-N. Feed valve, 3-10. Check valve;

[0027] 4. Material feeding subsystem; 4-1. Drain valve, 4-2. Material tank, 4-3. Discharge valve, 4-4. Material pressurizing tank, 4-5. Stop valve, 4-6. Stop valve, 4-7. Balancing valve, 4-8. Outlet valve, 4-9. Stop valve;

[0028] 5. Pressure reduction and separation system; 5-1. No. 1 intermediate heat exchanger, 5-2. First-stage pressure regulating valve, 5-3. Pressure reducing kettle, 5-4. Oil unloading valve, 5-5. No. 2 intermediate heat exchanger, 5-6. Second-stage pressure regulating valve, 5-7. Separation kettle, 5-8. Oil unloading valve, 5-9. Stop valve;

[0029] 6. Extract separation subsystem; 6-1-1, gate valve, 6-1-2, gate valve, 6-1-N gate valve, 6-2, gas-solid separation tank, 6-3, discharge valve, 6-4, slag storage tank, 6-5, drain valve, 6-6, stop valve, 6-7, gate valve, 6-8, stop valve. DETAILED DESCRIPTION

[0030] The following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise clearly indicated in the present invention, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "comprising" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations;

[0032] The following is combined with Figure 1 , the present invention is described in detail:

[0033] This embodiment discloses a supercritical fluid fluidized continuous extraction and separation system, such as Figure 1 As shown, the system consists of a supercritical fluidized continuous extraction system, a pressure reduction and separation system 5, a supercritical working medium refrigeration system 1, and a supercritical fluid circulation and pressurization system 2; wherein the supercritical fluidized continuous extraction system includes a material feeding subsystem 4, a material fluidized extraction subsystem 3, and a raffinate separation subsystem 6;

[0034] The material feeding subsystem 4 is composed of an emptying valve 4-1, a material tank 4-2, a discharge valve 4-3, a balancing valve 4-7, a material pressurizing tank 4-4, a stop valve 4-5, a stop valve 4-6, an outlet valve 4-8, and a stop valve 4-9; the material tank 4-2 is connected to the material pressurizing tank 4-4 through the discharge valve 4-3 and the balancing valve 4-7, and the material pressurizing tank 4-4 outlet is connected to the material fluidization extraction subsystem 3 through the outlet valve 4-8; the addition of the extracted material is powered by the supercritical fluid circulated in the system, and the material is added for the first time After the system is emptied, the discharge valve 4-3 of the material tank 4-2 is opened, and the material enters the material pressurization tank 4-4 by gravity. Then, the stop valve 4-5 is opened, and the gaseous extractant from the original gas cylinder is blown from the material pressurization tank 4-4 through the outlet valve 4-8, the feed valve 3-2-1, the feed valve 3-2-1 to the feed valve 3-2-N, the feed valve 3-9-1, and the feed valve 3-9-2 to the feed valve 3-9-N to the extracted material in the material pressurization tank 4-4 into the cyclone extractors 3-3-1, cyclone extractors 3-3-2, and cyclone extractors 3-3-N. Subsequent material loading is carried out by transferring the material in the material pressurization tank via the gaseous extractant in the separation kettle 5-7. The material pressure tank 4-4 storing the extraction medium first balances the pressure with the material tank 4-2 through the balance valve 4-7, and then opens the discharge valve 4-3 to charge the material by gravity. After the charging is completed, the stop valve 4-6 is opened, and the gaseous extractant from the separation kettle 5-7 blows the extracted material in the material pressure tank 4-4 into the cyclone extractor, completing the recharging process.

[0035] The material fluidized extraction subsystem 3 is mainly composed of a circulation pump, one or more parallel cyclone extractors 3-3-1, and cyclone extractors 3-3-2 to cyclone extractors 3-3-N: the material to be extracted in the material pressurizing tank 4-4 is blown into the cyclone extractors 3-3-1 to 3-3-N by the gaseous extractant from the separation kettle. After the feeding is completed, the outlet valve 4-8 of the material pressurizing tank 4-4 is closed, and the stop valve 3-1 and the feed valves 3-2-1 to 3-2-N are opened, so that the supercritical fluid from the supercritical fluid circulation and pressurizing system 2 enters the cyclone extractors 3-3-1 to cyclone extractors 3-3-N tangentially, collides with the extracted material in the cyclone extractors 3-3-1 to 3-3-N, and is fully mixed to form cyclonic fluidization, thereby improving the extraction efficiency. The supercritical fluid carrying the extracted solute flows through the filter from cyclone extractor 3-3-1 to the overflow port at the top of cyclone extractor 3-3-N. The overflow port from cyclone extractor 3-3-1 to the top of cyclone extractor 3-3-N is divided into two paths through a three-way connection: one path is connected to the pressure reduction separation system 2, and the other path is connected to the extractor self-circulation system. At the initial stage of extraction, when the extraction medium has not yet reached saturation, valves 3-5-1 to 3-5-N are closed, valves 3-6-1 to 3-6-N are opened, and circulation pumps 3-8-1 to 3-8-N are started, so that the supercritical fluid is repeatedly circulated into cyclone extractors 3-3-1 to 3-3-N until the supercritical fluid in the extractors reaches or approaches saturation. Valve 3-6-1 to 3-6-N and circulation pump 3-8-1 to 3-8-N are closed, valves 3-5-1 to 3-5-N are opened, and the supercritical fluid saturated with the extracted solute enters the decompression separation system 5 for decompression separation. The raffinate enters the raffinate separation subsystem 6 from the material outlet of cyclone extractor 3-3-1 to cyclone extractor 3-3-N, completing one material extraction and separation process.

[0036] The decompression separation system 5 is composed of a No. 1 intermediate heat exchanger 5-1, a first-stage pressure regulating valve 5-2, a pressure reducing kettle 5-3, an oil unloading valve 5-4, a No. 2 intermediate heat exchanger 5-5, a second-stage pressure regulating valve 5-6, a separation kettle 5-7, an oil unloading valve 5-8, and a stop valve 5-9. After the supercritical extractant reaches or approaches saturation, the supercritical fluid carrying the extraction solute enters the hot flow side of the No. 1 intermediate heat exchanger 5-1 through the overflow ports of the cyclone extractors 3-3-1 to 3-3-N, and undergoes a second reaction with the supercritical fluid on the cold flow side of the No. 1 intermediate heat exchanger 5-1 after being condensed, liquefied, and pressurized. After the first heat exchange, it enters the pressure reducing kettle 5-3 through the first-level pressure regulating valve 5-2, and then enters the hot flow side of the No. 2 intermediate heat exchanger 5-5. After the second heat exchange with the supercritical fluid on the cold flow side of the No. 2 intermediate heat exchanger 5-5, it enters the separation kettle 5-7 through the second-level pressure regulating valve 5-6. At this time, the supercritical fluid changes into a gaseous state after two throttling and pressure reduction. The solute dissolved in the supercritical fluid accumulates in the separation kettle 5-7 in the form of liquid. The gaseous extractant can enter the supercritical fluid circulation and pressurization system 2 or be used as power for re-feeding the material.

[0037] The extract separation subsystem 6 comprises gate valves 6-1-1 to 6-1-N, a gas-solid separation tank 6-2, and a slag storage tank 6-4. After extraction is complete, the pressure within the cyclone extractors 3-3-1 to 3-3-N reaches equilibrium with the pressure within the separation kettle 5-7. The shutoff valve 4-9 and shutoff valves 3-9-1 to 3-9-N are opened, the feed valves 3-2-1 to 3-2-N are closed, and the gate valves 6-1-1 to 6-1-N are opened. The extract is then blown into the gas-solid separation tank 6-2 by the gaseous extraction medium from the separation kettle. The gaseous extractant therein flows from the upper gas outlet of the gas-solid separation tank 6-2 through gate valve 6-7 and enters the system pipeline of the supercritical fluid circulation pressurization system 2. The extractant in the gas-solid separation tank 6-2 is connected to the slag storage tank 6-4 via the discharge valve 6-3. The small amount of gaseous extractant in the slag storage tank 6-4 can be used to empty the material tank 4-2 of the material pressurization subsystem 4.

[0038] The supercritical working medium refrigeration system is composed of an extractant cylinder 1-1, a filling valve 1-2, and a refrigeration unit 1-3; the gaseous extractant in the cylinder 1-1 enters the refrigeration unit 1-3 through the filling valve 1-2, is cooled and liquefied, and then enters the supercritical fluid circulation and pressurization system 2.

[0039] Furthermore, based on the supercritical fluid fluidized continuous extraction and separation system disclosed above, this embodiment also discloses a supercritical fluid extraction and separation process, and the specific process steps are as follows:

[0040] (1) First, open the balancing valve 4-7 and the discharge valve 4-3, and fill the material required for one extraction from the material tank to the material pressure tank, close the discharge valve 4-3, and then empty the system. Open the charging valve 1-2, stop valve 2-4, stop valve 3-1, stop valve 4-5, outlet valve 4-8, feed valves 3-2-1 to 3-2-N, stop valves 3-9-1 to 3-9-N, stop valves 3-5-1 to 3-5-N, first-stage pressure regulating valve 5-2, second-stage pressure regulating valve 5-6, and stop valve 5-9 in sequence, then open gate valves 6-1-1 to 6-1-N, gate valve 6-7, drain valve 2-1, and drain valve 4-1 in sequence, open the extractant gas cylinder 1-1, and drain the system. After a period of time, close the drain valve 2-1, drain valve 4-1, and gate valve 6-7, and open the discharge valve 6-3 and drain valve 6-5. After draining, start the refrigeration unit 1-3 and open the charging valve 1-2 to complete the refrigeration of the supercritical working medium.

[0041] (2) Close the balancing valve 4-7, open the stop valve 2-4, stop valve 4-5, outlet valve 4-8, feed valves 3-2-1 to 3-2-N, stop valves 3-9-1 to 3-9-N, open the filling valve 1-2, use the pressure in the extractant gas cylinder to blow the material to be extracted in the raw material pressure tank 4-4 into the cyclone extractors 3-3-1 to 3-3-N, and close the outlet valve 4-8 and stop valve 2-4. Turn on the refrigeration unit 1-3, the pressure pump 2-5 and the circulation heater 2-8 to liquefy, pressurize and heat the gaseous extractant to convert it into a supercritical extractant suitable for extraction. Open the stop valve 3-1 to allow the supercritical extractant to enter the cyclone extractors 3-3-1 to 3-3-N, and allow the materials in the extractors and the supercritical extractant to form a cyclonic fluidization. Close the stop valves 3-5-1 to 3-5-N and the gate valves 6-1-1 to 6-1-N, open the stop valves 3-6-1 to 3-6-N and turn on the circulation pumps 3-8-1 to 3-8-N, so that the supercritical extractant forms a self-circulation in the cyclone extractor until the supercritical extractant extraction reaches or approaches saturation.

[0042] (3) After the supercritical extractant reaches or approaches saturation, the stop valves 3-6-1 to 3-6-N and the circulation pumps 3-8-1 to 3-8-N are closed, and the stop valves 3-5-1 to 3-5-N are opened. The supercritical extractant carrying the extracted solute flows from the overflow ports of the cyclone extractors 3-3-1 to 3-3-N through the No. 1 intermediate heat exchanger 5-1 and the first-stage pressure regulating valve 5-2 into the pressure reducing kettle 5-3. The supercritical extractant that has been reduced in pressure and cooled flows from the pressure reducing kettle through the No. 2 intermediate heat exchanger 5-5 and the second-stage pressure regulating valve 5-6 into the separation kettle 5-7. In the separation kettle 5-7, the supercritical extractant is further reduced in pressure and cooled, and changes into a gaseous extractant, thereby releasing the extracted solute, which remains in the separation kettle 5-7. The gaseous extractant in the separation kettle 5-7 is returned to the refrigeration unit 1-3 through the buffer tank 2-2 and the one-way valve 2-3. After liquefaction is completed, it re-enters the supercritical fluid circulation and pressurization system 2, thereby realizing the recycling of the supercritical extractant until the materials in the cyclone extractors 3-3-1 to 3-3-N are completely extracted.

[0043] (4) After the extraction is completed, the stop valve 3-1, stop valves 3-5-1 to 3-5-N, stop valves 3-6-1 to 3-6-N, pressure regulating valve, and stop valve 4-6 are closed, and the stop valve 4-9, gate valves 6-1-1 to 6-1-N, and gate valve 6-7 are opened. The gaseous extractant from the separation kettle 5-7 is used to blow the residue in the cyclone extractors 3-3-1 to 3-3-N into the gas-solid separation tank 6-2. The gaseous extractant separated by the gas-solid separation tank 6-2 is re-integrated into the supercritical fluid circulation and pressurization system 2 through the gate valve 6-7. After the material transportation in the cyclone extractors 3-3-1 to 3-3-N is completed, the gate valves 6-1-1 to 6-1-N and the gate valve 6-7 are closed, the stop valve 6-6 is closed, the stop valve 6-8 and the drain valve 6-5 are opened, and the slag storage tank 6-4 is emptied. Then, the stop valve 6-8 and the drain valve 6-5 are closed, and the discharge valve 6-3 is opened. The solid residue separated by the gas-solid separation tank 6-2 enters the slag storage tank 6-4 through the discharge valve 6-3, completing one batch of material extraction.

[0044] (5) Re-feeding of materials: After the material tank 4-2 is re-fed, the drain valve 4-1 is opened, the discharge valve 4-3 and the balancing valve 4-7 are closed, and the stop valve 6-6 is opened. The material tank 4-2 is emptied by using the gaseous extractant remaining in the slag storage tank 6-4. Then, the drain valve 4-1 is closed, the balancing valve 4-7 and the discharge valve 4-3 are opened, and a certain amount of the material to be extracted in the material tank 4-2 falls into the material pressurizing tank 4-4 by gravity. The discharge valve 4-3 and the balancing valve 4-7 are closed, the stop valve 4-9 is closed, and the stop valve 4-6 is opened. The material to be extracted in the material pressurizing tank 4-4 is blown into the cyclone extractors 3-3-1 to 3-3-N by using the gaseous extractant in the separation kettle 5-7, and the re-feeding is completed.

[0045] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A supercritical fluid fluidized continuous extraction and separation system, characterized in that: The system comprises a material feeding subsystem, a material fluidization extraction subsystem, an extract separation subsystem, a pressure reduction separation system, a supercritical working medium refrigeration system and a supercritical fluid circulation and pressurization system; the material feeding subsystem is connected to the material fluidization extraction subsystem, and the material fluidization extraction subsystem is composed of one or more parallel cyclone extractors and a circulation pump, and the cyclone extractor is provided with a supercritical fluid inlet, a material outlet and an overflow port; The supercritical fluid output from the supercritical fluid circulation boosting system enters the cyclone extractor tangentially from the supercritical fluid inlet, forming a fluidized cyclone with the extracted material, causing shearing and particle collision and crushing between the supercritical fluid and the extracted material, thereby accelerating the extraction; the supercritical fluid carrying the solute is discharged from the overflow port and is pumped back into the cyclone extractor through the circulation pump until the supercritical fluid reaches a saturated state, and then enters the pressure reduction separation system from the supercritical fluid outlet; the extractant discharged from the material outlet enters the extractant separation subsystem; the supercritical working fluid refrigeration system cools and liquefies the extractant, and then sends it to the supercritical fluid circulation system. The supercritical fluid circulation and pressurization system cools and pressurizes the gaseous extraction medium from the pressure reduction separation system to become a supercritical fluid, and sends it back to the cyclone extractor; the gaseous extraction medium of the pressure reduction separation system sends the extracted material in the material feeding subsystem back into the cyclone extractor; the pressure reduction separation system includes a separation kettle, and the gaseous extraction medium outlet of the separation kettle is also connected to the material feeding subsystem and the supercritical fluid circulation and pressurization system; a part of the gaseous extraction medium is used to transport the material in the material pressure tank, and a part of the gaseous extraction medium is returned to the supercritical fluid circulation and pressurization system.

2. The supercritical fluid fluidized continuous extraction and separation system according to claim 1, characterized in that: The pressure reduction and separation system also includes a No. 1 intermediate heat exchanger, a No. 2 intermediate heat exchanger, and a pressure reducing kettle; the hot flow side inlet of the No. 1 intermediate heat exchanger is connected to the overflow port of the cyclone extractor, and the hot flow side outlet of the No. 1 intermediate heat exchanger is connected to the pressure reducing kettle through a first-level pressure regulating valve; the outlet of the pressure reducing kettle is connected to the hot flow side inlet of the No. 2 intermediate heat exchanger, and the hot flow side outlet of the No. 2 intermediate heat exchanger is connected to the separation kettle through a second-level pressure regulating valve.

3. The supercritical fluid fluidized continuous extraction and separation system according to claim 1, wherein: The material feeding subsystem consists of a material tank and a material pressurizing tank; a drain valve is provided at the upper end of the material tank, and a balancing valve is connected between the material tank and the material pressurizing tank; the discharge port of the material pressurizing tank is connected to the cyclone extractor; and the material pressurizing tank is also connected to the gaseous extraction medium outlet of the separation kettle.

4. The supercritical fluid fluidized continuous extraction and separation system according to claim 1, wherein: The supercritical fluid circulation and pressurization system consists of a buffer tank, a circulation heater, a pressure pump, a No. 3 intermediate heat exchanger, and a supercritical working fluid refrigeration system; the buffer tank is connected to the supercritical working fluid refrigeration system, and the supercritical working fluid refrigeration system changes the gaseous extractant into a liquid state; after being pressurized by the pressure pump to the pressure required by the extraction process, it changes into the supercritical state required by the extraction process through the No. 3 intermediate heat exchanger and the circulation heater, and enters the supercritical fluidization extraction subsystem.

5. The supercritical fluid fluidized continuous extraction and separation system according to claim 1, wherein: The supercritical working medium refrigeration system is composed of an extractant gas cylinder, a filling valve, and a refrigeration unit. The extractant in the extractant gas cylinder enters the refrigeration unit through the filling valve to be cooled and liquefied, and then enters the supercritical fluid circulation and pressurization system.

6. The supercritical fluid fluidized continuous extraction and separation system according to claim 1, wherein: The extract separation subsystem consists of a slag storage tank and a gas-solid separation tank. The gas outlet at the upper end of the gas-solid separation tank enters the system pipeline of the supercritical fluid circulation pressurization system through a gate valve; the extract outlet in the gas-solid separation tank is connected to the slag storage tank through a discharge valve.

7. The supercritical fluid fluidized continuous extraction and separation system according to claim 1, wherein: The extract residue is blown into the gas-solid separation tank by the gaseous extraction medium from the separation kettle.

8. The supercritical fluid fluidized continuous extraction and separation system according to claim 1, wherein: The overflow port of the cyclone extractor is equipped with a filter screen and a backwashing device.

9. The separation process based on the supercritical fluid fluidized continuous extraction separation system according to any one of claims 1 to 8, characterized in that: as follows: The material is first added after the system is emptied. The material enters the material pressurizing tank by gravity, and the gaseous extractant from the original gas cylinder blows the extracted material in the material pressurizing tank to the cyclone extractor; after the extracted material reaches a certain amount, the outlet valve of the material pressurizing tank is closed, and the supercritical fluid circulation and pressurization system is opened. The supercritical fluid output by the supercritical fluid circulation and pressurization system enters the cyclone extractor tangentially to form fluidized mixing with the extracted material for extraction; the supercritical fluid carrying the extraction solute flows out from the overflow port at the upper end of the cyclone extractor, returns to the cyclone extractor through the circulation pump, and until the supercritical extractant reaches or is close to saturation, the circulation pump is turned off, and enters the pressure reduction separation system from the overflow port at the upper end of the cyclone extractor. The pressure reduction separation system changes the supercritical fluid into a gaseous state, separates the extraction solute, and stores it in a separation kettle in liquid form. Part of the gaseous extraction medium is used to transport the material in the material pressurizing tank, and part of it flows back to the supercritical fluid circulation and pressurization system; The raffinate enters the raffinate separation subsystem from the material outlet of the cyclone extractor for separation; during the whole process, the material is added by transporting the material in the material pressure tank through the gaseous extractant separated by the pressure reduction separation system.

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