A gas-filled subcritical carbon dioxide fluidized bed continuous extraction and separation system and method

Abstract

This invention discloses a gas-filled subcritical carbon dioxide fluidized bed continuous extraction and separation system and method, belonging to the fields of separation technology and chemical machinery equipment, and can be widely used in chemical, food, medical, and petroleum industries. The system, through the coordination of a subcritical carbon dioxide refrigeration and pressurization circulation subsystem, a material feeding subsystem, a nitrogen pressurization jet subsystem, a subcritical carbon dioxide fluidized bed continuous extraction subsystem, and a depressurization separation subsystem, transforms the traditional fixed-bed extractor into a fluidized-bed extractor by blowing nitrogen into the extraction vessel, thus achieving continuous extraction. Based on existing technologies, this invention uses high-pressure nitrogen circulation within the system to achieve continuous feeding, discharging, and fluidized bed extraction. The system is highly efficient, energy-saving, and environmentally friendly, solving the problem in existing technologies where complete continuous extraction and separation of materials cannot be achieved during subcritical fluid extraction.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of separation process and chemical machinery equipment, and particularly relates to a kind of aerated subcritical carbon dioxide fluidization continuous extraction separation system and method. BACKGROUND

[0002] The information disclosed in this BACKGROUND section is only for the purpose of increasing the understanding of the general background of the application and does not necessarily constitute an admission by the patent applicant(s) that this information constitutes prior art.

[0003] With the rapid development of industrial technology, subcritical extraction technology gradually matures and is widely used. Compared with other separation methods, subcritical fluid extraction has many advantages such as non-toxic, harmless, environmental protection, no pollution, low operation cost, easy product separation, etc., and is mainly applied to the extraction of natural food, oil and organic biological substances. However, the current subcritical fluid extraction device mostly uses a fast-opening sealed intermittent device, which leads to low production efficiency, large energy loss, and high operation cost. Moreover, due to frequent opening of the extractor, the safety and reliability of the device are reduced, and the extraction medium is greatly wasted, which restricts the industrialization of subcritical fluid extraction technology.

[0004] Patent CN108654135A discloses a subcritical fluid isobaric extraction separation system and process flow. The system is composed of a buffer unit, a liquefaction unit, a pressurized circulation unit, an extraction unit, a heat exchange unit, a gasification unit, a separation unit, a discharge unit, and a filtration unit. The subcritical fluid in the extraction unit and the gaseous subcritical fluid medium in the separation unit are in an isobaric state, and a heat exchange unit for subcritical fluid and gaseous subcritical fluid medium is provided, which reduces the energy consumption of the system and saves energy. The invention has the advantages of simple process flow, small equipment investment, and low operation cost. However, the material needs to be repeatedly loaded and unloaded, and the continuous extraction and separation of the material cannot be achieved, which has safety hazards and low extraction efficiency.

[0005] Patent CN110152350A discloses a subcritical fluid continuous isobaric extraction separation device system and extraction separation process. The device controls the opening and closing of the valve through a PLC program to control the pressure balance in each extractor, which to some extent realizes the continuous extraction and separation of subcritical fluid. However, the loading and unloading of the material in the extractor is still carried out intermittently by manual operation, and the true continuous extraction is not achieved, but a semi-continuous extraction system. Although the invention has high automation degree and reliable operation, it is still a traditional fixed bed extraction method, which also has safety hazards caused by repeated opening and closing of the extractor, large loss of extraction agent, high sealing requirement, and severe wear of the sealing parts, which need to be frequently replaced. SUMMARY

[0006] In order to solve the problems of the prior art, the present application aims to provide a system and method for continuous extraction and separation of gaseous subcritical carbon dioxide fluidization, which converts the traditional fixed-bed subcritical carbon dioxide extraction mode into a fluidized-bed extraction mode by blowing high-pressure nitrogen into the extraction kettle, so that the subcritical carbon dioxide extractant and the material particles in the extraction kettle are mixed in a fluidized state, thereby greatly improving the extraction efficiency. Moreover, the high-pressure nitrogen circulating in the system is used to charge and discharge the extraction kettle, thereby truly realizing the continuity of the extraction process.

[0007] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0008] In a first aspect, the present application provides a system for continuous extraction and separation of gaseous subcritical carbon dioxide fluidization, which comprises a subcritical carbon dioxide refrigeration and pressurization circulation subsystem, a material charging subsystem, a nitrogen pressurized jet subsystem, a subcritical carbon dioxide fluidization continuous extraction subsystem, and a depressurization and separation subsystem.

[0009] The subcritical carbon dioxide fluidization continuous extraction subsystem comprises a subcritical carbon dioxide fluidization continuous extractor unit and a nitrogen pressurized circulation unit. The subcritical carbon dioxide fluidization continuous extractor unit comprises one or more extractors. The internal space of the extractor is divided into an upper region and a lower region by a filter screen. The upper region of the filter screen is provided with a nitrogen inlet and a nitrogen outlet. The lower region of the filter screen is provided with a material inlet and a subcritical carbon dioxide inlet. The bottom of the extractor is provided with a nitrogen inlet, a raffinate outlet, and a subcritical carbon dioxide outlet. The nitrogen inlet is connected to the nitrogen pressurized circulation unit and the nitrogen pressurized jet subsystem, respectively. The nitrogen outlet is connected to the nitrogen pressurized circulation unit. The subcritical carbon dioxide outlet is connected to the depressurization and separation subsystem. The nitrogen pressurized circulation unit blows high-pressure nitrogen into the extractor, so that the subcritical carbon dioxide extractant and the material to be extracted in the extractor are mixed in a fluidized state. The subcritical carbon dioxide extractant is discharged from the extractor after reaching or approaching saturation.

[0010] The subcritical carbon dioxide refrigeration and pressurization circulation subsystem cools, liquefies, and pressurizes the carbon dioxide in the system to a subcritical state, which is used by the material charging subsystem and the subcritical carbon dioxide fluidization continuous extraction subsystem.

[0011] The nitrogen pressurized jet subsystem uses the high-pressure nitrogen circulating in the system to send the mixture of the material to be extracted and the subcritical carbon dioxide into the subcritical carbon dioxide fluidization continuous extraction subsystem.

[0012] In the present application, the material inlet of the extractor is connected with the nitrogen pressurized jet subsystem, the metered material to be extracted is delivered to the extractor through the nitrogen pressurized jet subsystem, and after a certain amount is reached, the nitrogen pressurized jet subsystem is closed. The nitrogen pressurized circulation subsystem is opened, nitrogen enters the nitrogen storage tank from the top of the extractor through the mist eliminator, and then nitrogen enters from the nitrogen inlet at the bottom of the extractor, blows the material, and forms fluidization to accelerate extraction. During extraction, fresh subcritical carbon dioxide can be introduced to ensure that the extraction is close to or reaches saturation. The bottom of the extractor is provided with a subcritical carbon dioxide outlet, and the subcritical carbon dioxide at the end of extraction enters the pressure reduction separation subsystem through the bottom outlet. The discharged subcritical carbon dioxide contains a small amount of nitrogen, which is separated from the subcritical carbon dioxide by a gas-liquid separator, and the nitrogen enters the raffinate separation subsystem, while the subcritical carbon dioxide enters the raffinate pressure reduction separation unit. The high-pressure nitrogen input through the nitrogen inlet or the material inlet above the filter screen in the extractor blows the raffinate out of the extractor and into the raffinate separation unit through the raffinate outlet.

[0013] In an embodiment of the present application, the subcritical carbon dioxide refrigeration pressurized circulation subsystem comprises a carbon dioxide storage tank, a cooler, a pressurizing pump and a thermostat connected in sequence; the carbon dioxide separated by the pressure reduction separation subsystem is cooled in the cooler. The subcritical carbon dioxide refrigeration pressurized circulation subsystem of the present application cools, liquefies and pressurizes the carbon dioxide to a subcritical state, and stabilizes its temperature through the thermostat, for use in the material feeding subsystem and the subcritical fluid nitrogen fluidization continuous extraction subsystem.

[0014] In an embodiment of the present application, the material feeding subsystem comprises a storage tank and a feeding tank connected in sequence, the storage tank stores the material to be extracted, and the material to be extracted in the storage tank enters the feeding tank by gravity; and a subcritical carbon dioxide storage tank and a pressurizing pump connected in sequence, the pressurizing pump is connected with the feeding tank, and the subcritical carbon dioxide extractant and the material to be extracted are mixed in the feeding tank. The material feeding subsystem of the present application mixes the material to be extracted and the subcritical carbon dioxide extractant first, so that the material is fully soaked in the feeding tank before entering the extractor, thereby shortening the storage and extraction time and improving the extraction efficiency.

[0015] The upper end of the storage tank is provided with a vent valve, the material to be extracted is sent into the storage tank through the feed valve, and after the air in the tank is discharged by using the gas in the storage tank or gas cylinder, the material to be extracted falls into the feeding tank by gravity. In the feeding tank, the subcritical carbon dioxide circulating in the system is mixed with the material to be extracted, and the two are subjected to soaking treatment in the feeding tank. After the jet pump is started, the pressurizing pump is opened, and the subcritical fluid in the subcritical carbon dioxide storage tank is sent into the feeding tank to prevent the feeding tank from being vacuumed. Then the extracted material is sent into the extractor to complete a feeding process.

[0016] In one embodiment of the present application, the nitrogen pressurized jet subsystem comprises, in sequence, a nitrogen storage tank, a compressor, a first nitrogen buffer tank, and a flow jet pump. The flow jet pump uses high-pressure nitrogen to send the mixture of the subcritical carbon dioxide extractant and the material to be extracted in the material feeding subsystem into the extractor through the material inlet. The nitrogen storage tank is connected to a nitrogen source and is connected to the nitrogen inlet of the extractor through a one-way valve.

[0017] After the nitrogen is discharged from the cylinder, it enters the nitrogen storage tank. The nitrogen in the nitrogen storage tank is compressed by the compressor and is injected into the extractor through the first buffer tank and the flow jet pump. The other route is through the valve into the extractor, and then the raffinate is blown into the raffinate separation subsystem using the pressure difference, while the nitrogen and the raffinate are separated to allow the nitrogen to be recycled.

[0018] The filling of the material is carried out by the flow jet pump using nitrogen as the working medium. The high-pressure nitrogen compressed by the compressor is sprayed at high speed from the nozzle of the flow jet pump working inlet. A vacuum state is formed at the throat, thereby sucking the material to be extracted and the subcritical carbon dioxide fluid in the feeding tank. At this time, the material to be extracted and the subcritical carbon dioxide fluid are mixed and exchange momentum in the throat, so that the kinetic energy of the transported material increases. Finally, most of the kinetic energy is converted into pressure energy through the diffuser pipe and injected into the extractor.

[0019] In one embodiment of the present application, the nitrogen pressurized jet subsystem further comprises a second nitrogen buffer tank connected to the nitrogen storage tank. The nitrogen separated by the pressure reduction separation subsystem enters the second nitrogen buffer tank and then enters the nitrogen storage tank through a pipeline, thereby realizing the recycling of nitrogen.

[0020] In one embodiment of the present application, the pressure reduction separation subsystem comprises a gas-liquid separation unit, a raffinate separation unit, and an extract pressure reduction separation unit.

[0021] The gas-liquid separation unit is used to separate the subcritical carbon dioxide carrying solutes and nitrogen. It comprises a gas-liquid separator. The subcritical carbon dioxide outlet of the extractor is connected to the gas-liquid separator. The separated nitrogen enters the nitrogen pressurized jet subsystem, and the separated subcritical carbon dioxide carrying solutes enters the extract pressure reduction separation unit.

[0022] The raffinate separation unit is used to separate the raffinate and nitrogen. It comprises, in sequence, a gas-solid separator and a residue storage tank. The raffinate outlet of the extractor is connected to the gas-solid separator. The separated nitrogen is transported to the nitrogen pressurized jet subsystem, and the separated raffinate enters the residue storage tank. The small amount of gas separated from the residue storage tank is introduced into the material feeding subsystem for emptying.

[0023] The extract decompression separation unit comprises a heat exchanger, a heater, a decompression kettle and a separation kettle, the heat exchanger is connected with the liquid outlet of the gas-liquid separator, the outlet of the heat exchanger is connected with the first heater, the first heater is connected with the decompression kettle, the decompression kettle is connected with the second heater, the second heater is connected with the separation kettle, and the gas in the separation kettle is transported to the subcritical carbon dioxide refrigeration pressurization circulation subsystem.

[0024] In one embodiment of the present application, in the extract decompression separation unit, the heat generated by the cooler in the subcritical carbon dioxide refrigeration pressurization circulation subsystem is used by the heat exchanger.

[0025] In one embodiment of the present application, in the extract decompression separation unit, the heat generated by the cooler in the subcritical carbon dioxide refrigeration pressurization circulation subsystem is used by the heat exchanger.

[0026] In one embodiment of the present application, the nitrogen pressurization circulation unit comprises a nitrogen storage tank and a compressor connected with each other, the nitrogen storage tank is connected with the two nitrogen inlets of the extractor, and the nitrogen outlet of the extractor is connected with the compressor; during the extraction process, the high-pressure nitrogen enters the extractor from the nitrogen inlet at the bottom of the extractor to blow the material to be extracted, so that the material to be extracted is fluidized and the extraction is accelerated, and the nitrogen enters the compressor from the nitrogen outlet at the upper region of the filter screen for recycling; after the extraction is completed, the high-pressure nitrogen enters the extractor from the nitrogen inlet at the upper region of the filter screen of the extractor, and the raffinate is blown into the decompression separation subsystem through the raffinate outlet.

[0027] In the second aspect of the present application, a gaseous subcritical carbon dioxide fluidization continuous extraction and separation method is provided, which uses the gaseous subcritical carbon dioxide fluidization continuous extraction and separation system described above, and comprises the following steps:

[0028] The material to be extracted is stored in the material feeding subsystem, and the material to be extracted and the subcritical carbon dioxide mixture are injected into the extractor by the jet pump; the nitrogen pressurization jet subsystem and the nitrogen pressurization circulation unit are opened, and the nitrogen is injected into the extractor, the nitrogen is used to circulate and blow the material to be extracted and the subcritical carbon dioxide mixture in the extractor between the extractor and the nitrogen pressurization circulation unit, so that the material to be extracted and the subcritical carbon dioxide mixture are fluidized and extracted, until the subcritical carbon dioxide in the extractor reaches or approaches the saturated state, the self-circulation of the nitrogen in the extractor is stopped, and the subcritical carbon dioxide in the extractor is discharged to the decompression separation subsystem for separation.

[0029] After the material extraction is completed, the subcritical carbon dioxide carrying solutes enters the gas-liquid separation unit through the subcritical carbon dioxide outlet, and after the separation of the mixed nitrogen, the subcritical carbon dioxide carrying solutes enters the extract depressurization separation unit, and after two throttling depressurization, the subcritical carbon dioxide is phase changed into gaseous carbon dioxide, and the solutes dissolved therein are released, and the gaseous carbon dioxide reenters the subcritical carbon dioxide refrigeration pressurization circulation subsystem for recycling.

[0030] After the material extraction is completed, the nitrogen pressurized jet subsystem is started, high-pressure nitrogen is input into the extractor through the nitrogen inlet at the upper part of the extractor filter screen, the raffinate is blown into the raffinate separation unit by the high-pressure nitrogen, the separated nitrogen enters the nitrogen pressurized jet subsystem, and the separated raffinate enters the residue storage tank, and a small amount of gas contained in the residue storage tank enters the material storage tank of the material feeding subsystem for subsequent emptying.

[0031] In some embodiments of the present application, the subcritical carbon dioxide fluidized continuous extractor unit is composed of one or more extractors, and the continuous extraction process is realized by the sequential feeding and discharging of the multiple extractors.

[0032] In some embodiments of the present application, during the extraction process, the subcritical carbon dioxide fluid is supplemented into the extractor by the subcritical carbon dioxide refrigeration pressurization circulation subsystem to ensure that the extraction can reach or approach saturation.

[0033] In some embodiments of the present application, after the material extraction is completed, the nitrogen pressurized circulation unit is started, high-pressure nitrogen is input into the extractor through the material inlet of the extractor, and the raffinate is blown into the raffinate separation unit by the high-pressure nitrogen.

[0034] The present application has the following beneficial effects:

[0035] The present application provides an inflatable subcritical carbon dioxide fluidized continuous extraction and separation system, which is capable of converting the traditional fixed bed extractor into a fluidized bed extractor by blowing nitrogen into the extraction kettle, realizing the continuity of the extraction process, increasing the contact area through the fluidized mixing of the subcritical carbon dioxide and the extracted material particles in the extraction kettle, shortening the extraction time, improving the extraction efficiency, feeding and discharging the extractor by the high-pressure nitrogen circulating in the system, truly realizing the continuous operation of feeding, extraction and discharging, and greatly improving the economic benefit.

[0036] In summary, the present application, on the basis of the existing technology, realizes continuous feeding, discharging and fluidized extraction by circulating high-pressure nitrogen in the system, and the system is efficient, energy-saving and environmentally friendly, solving the problem that complete continuous extraction separation of materials cannot be realized in subcritical fluid extraction in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0037] The accompanying drawings, which form a part of this specification, are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The embodiments of the present application, and their

[0038] Figure 1 Process flow chart of the inflatable subcritical carbon dioxide fluidized continuous extraction separation system of the present application.

[0039] Reference Signs:

[0040] 1, subcritical carbon dioxide refrigeration pressurization subsystem: 1-1, carbon dioxide cylinder, 1-2, stop valve, 1-3, cooler, 1-4, stop valve, 1-5, pressurization pump, 1-6, control valve, 1-7, thermostat, 1-8, check valve.

[0041] 2, material feeding subsystem: 2-1, stop valve, 2-2, subcritical carbon dioxide storage tank, 2-3, stop valve, 2-4, pressurization pump, 2-5, control valve, 2-6, feeding tank, 2-7, balance valve, 2-8, gate valve, 2-9, storage tank, 2-10, emptying valve, 2-11, feeding valve, 2-12, discharging valve.

[0042] 3, nitrogen pressurized jet subsystem: 3-1, nitrogen cylinder, 3-2, stop valve, 3-3, nitrogen storage tank, 3-4, compressor, 3-5, stop valve, 3-6, nitrogen buffer tank, 3-7, emptying valve, 3-8, stop valve, 3-9, jet pump, 3-10, stop valve, 3-11, stop valve, 3-12, stop valve, 3-13, check valve, 3-14, balance valve, 3-15, nitrogen buffer tank, 3-16, emptying valve, 3-17, stop valve.

[0043] 4, subcritical carbon dioxide fluidized continuous extractor unit: 4-1-1 to 4-1-N, extractor, 4-2-1 to 4-2-N, demister, 4-3-1 to 4-3-N, stop valve, 4-4-1 to 4-4-N, check valve, 4-5-1 to 4-5-N, inlet valve, 4-6-1 to 4-6-N, stop valve, 4-7-1 to 4-7-N, stop valve, 4-8-1 to 4-8-N, outlet valve, 4-9-1 to 4-9-N, stop valve, 4-10-1 to 4-10-N, discharging valve.

[0044] 5, nitrogen pressurized circulation unit: 5-1, compressor, 5-2, stop valve, 5-3, stop valve, 5-4, nitrogen storage tank, 5-5, emptying valve, 5-6, stop valve.

[0045] 6, gas-liquid separator unit: 6-1, stop valve, 6-2, gas-liquid separator, 6-3, stop valve, 6-4, check valve.

[0046] 7, raffinate separation unit: 7-1, stop valve, 7-2, gas-solid separator, 7-3, stop valve, 7-4, check valve, 7-5, gate valve, 7-6, residue storage tank, 7-7, stop valve, 7-8, check valve, 7-9, discharge valve.

[0047] 8, extract depressurization separation unit: 8-1, stop valve, 8-2, heat exchanger, 8-3, pressure regulating valve, 8-4, heater, 8-5, pressure reduction kettle, 8-6, pressure regulating valve, 8-7, heater, 8-8, separation kettle, 8-9, discharge valve, 8-10, discharge valve, 8-11, emptying valve, 8-12, stop valve. DETAILED DESCRIPTION

[0048] In order for those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in conjunction with specific embodiments.

[0049] A kind of inflatable subcritical carbon dioxide fluidization continuous extraction separation system is disclosed in the embodiment, as shown in Figure Figure 1 It is composed of subcritical carbon dioxide refrigeration pressurized circulation subsystem 1, material feeding subsystem 2, nitrogen pressurized jet subsystem 3, subcritical fluid nitrogen fluidization continuous extraction system and separation system. Among them, subcritical carbon dioxide fluidization continuous extraction subsystem is composed of subcritical carbon dioxide fluidization continuous extractor unit 4 and nitrogen pressurized circulation unit 5;Depressurization separation subsystem is composed of gas-liquid separator unit 6, raffinate separation unit 7 and extract depressurization separation unit 8.

[0050] (1) The subcritical carbon dioxide refrigeration pressurization cycle subsystem 1 is composed of a carbon dioxide cylinder 1-1, a stop valve 1-2, a cooler 1-3, a stop valve 1-4, a pressurization pump 1-5, a control valve 1-6, a thermostat 1-7, and a check valve 1-8. The gaseous carbon dioxide in the carbon dioxide cylinder 1-1 enters the cooler 1-3 inlet through the stop valve 1-2, and the gaseous carbon dioxide is liquefied through the cooler 1-3, and then the liquid carbon dioxide is pressurized to the subcritical extraction required pressure by the pressurization pump 1-5. The liquid carbon dioxide flowing out of the pressurization pump 1-5 passes through the control valve 1-6, and becomes a subcritical fluid after being warmed by the thermostat 1-7, and then passes through the check valve 1-8, and is divided into two branches: one branch passes through the stop valve 4-9-1 to 4-9-N and is connected to the extractor 4-1-1 to 4-1-N, and the other branch passes through the stop valve 2-1 and enters the material feeding subsystem 2.

[0051] (2) The material feeding subsystem 2 is composed of a stop valve 2-1, a subcritical carbon dioxide storage tank 2-2, a stop valve 2-3, a pressurization pump 2-4, a control valve 2-5, a feeding tank 2-6, a balance valve 2-7, a gate valve 2-8, a storage tank 2-9, an emptying valve 2-10, a feeding valve 2-11, and a discharging valve 2-12. The subcritical carbon dioxide passes through the stop valve 2-1 and enters the subcritical carbon dioxide storage tank 2-2, and passes through the stop valve 2-3 and the control valve 2-5 and enters the feeding tank. When feeding for the first time, the extracted material passes through the feeding valve 2-11 and enters the storage tank 2-9, and the air in the storage tank 2-9 is discharged from the emptying valve 2-10 using the gas in the carbon dioxide cylinder 1-1. The extracted material in the storage tank 2-9 is weighed and enters the feeding tank 2-6 through the gate valve 2-8. After the extracted material in the feeding tank 2-6 is soaked with the subcritical carbon dioxide for a period of time, it is extracted by a jet pump and sprayed into the extractor. To avoid vacuumizing the feeding tank, the pressurization pump 2-4 is opened to send the subcritical carbon dioxide fluid into the feeding tank. The pressure between the storage tank 2-9 and the feeding tank 2-6 is balanced by the balance valve 2-7, and then the gate valve 2-8 is opened to load again by gravity. After the loading is completed, the air in the storage tank 2-9 is discharged from the emptying valve 2-10 using the gas in the storage tank 7-6, and the re-feeding process is completed.

[0052] (3) The nitrogen pressurized jet subsystem 3 is composed of a nitrogen cylinder 3-1, a stop valve 3-2, a nitrogen storage tank 3-3, a compressor 3-4, a stop valve 3-5, a nitrogen buffer tank 3-6, a vent valve 3-7, a control valve 3-8, a jet pump 3-9, a stop valve 3-10, a stop valve 3-11, a stop valve 3-12, a check valve 3-13, a balance valve 3-14, a nitrogen buffer tank 3-15, a vent valve 3-16, a stop valve 3-17. Nitrogen from the cylinder 3-1 enters the nitrogen storage tank 3-3 through the stop valve 3-2, and then enters the nitrogen buffer tank 3-6 through the compressor 3-4. Open the control valve 3-8 and the stop valve 3-11, and the high-pressure gas enters the material tank 2-6 through the jet pump 3-9. The material soaked in the tank is sucked into the extractor 4-1-1 to 4-1-N through the diffusion pipe of the jet pump and is injected into the extractor 4-1-1 to 4-1-N. The nitrogen in the nitrogen storage tank 3-3 enters the nitrogen buffer tank 3-15 through the stop valve 3-12, the check valve 3-13, the extractor 4-1-1 to 4-1-N, the gas-solid separator 7-2 and the matched valves, and then returns to the nitrogen storage tank 3-3 through the balance valve 3-14.

[0053] (4) The subcritical carbon dioxide fluidized continuous extraction subsystem is composed of a subcritical carbon dioxide fluidized continuous extractor unit 4 and a nitrogen pressurized circulation unit 5. Among them, the subcritical carbon dioxide fluidized continuous extractor unit 4 is composed of extractors 4-1-1 to 4-1-N, mist eliminators 4-2-1 to 4-2-N, stop valves 4-3-1 to 4-3-N, check valves 4-4-1 to 4-4-N, inlet valves 4-5-1 to 4-5-N, stop valves 4-6-1 to 4-6-N, stop valves 4-7-1 to 4-7-N, outlet valves 4-8-1 to 4-8-N, stop valves 4-9-1 to 4-9-N, and discharge valves 4-10-1 to 4-10-N. The material extracted by the jet pump is injected into the extractors 4-1-1 to 4-1-N through the inlet valves 4-5-1 to 4-5-N, and forms a fluidized extraction. During extraction, fresh subcritical carbon dioxide from the subcritical carbon dioxide refrigeration pressurized circulation subsystem 1 enters the extractors 4-1-1 to 4-1-N through the stop valves 4-9-1 to 4-9-N to ensure that the extraction is close to or reaches saturation. The subcritical carbon dioxide extracted to saturation enters the separation system from the outlet valves 4-8-1 to 4-8-N. The remaining raffinate is blown into the raffinate separation subsystem 7 from the bottom discharge valve 4-10-1 to 4-10-N of the extractor through the nitrogen in the nitrogen storage tank 3-3 in the nitrogen pressurized jet subsystem through the stop valve 3-12, the check valve 3-13, the stop valve 4-6-1 to 4-6-N.

[0054] The nitrogen pressurization circulating unit 5 is composed of a compressor 5-1, a stop valve 5-2, a stop valve 5-3, a nitrogen storage tank 5-4, an evacuation valve 5-5, and a stop valve 5-6. In the extractor, because the density of nitrogen is lower than that of the subcritical carbon dioxide fluid, nitrogen is discharged from the upper outlet, passes through the mist eliminator 4-2-1 to 4-2-N, the stop valve 4-3-1 to 4-3-N, and the one-way valve 4-4-1 to 4-4-N in parallel, enters the nitrogen pressurization circulating subsystem 5, the compressor 5-1 is started, nitrogen is pressurized by the compressor, enters the nitrogen storage tank 5-4 through the stop valve 5-3, and then reenters the extractor 4-1-1 to 4-1-N through the stop valve 5-6 and the stop valve 4-7-1 to 4-7-N, thereby completing the recycling of nitrogen, and nitrogen is blown from the lower inlet to form a fluidized extraction of the materials in the extractor.

[0055] (5) The pressure reduction separation subsystem includes a gas-liquid separation unit 6, a raffinate separation unit 7, and an extract pressure reduction separation unit 8. The gas-liquid separation unit 6 is composed of a stop valve 6-1, a gas-liquid separator 6-2, a stop valve 6-3, and a one-way valve 6-4. The subcritical carbon dioxide reaching the saturated state from the bottom of the extractor is discharged from the bottom outlet valve 4-8-1 to 4-8-N (with a small amount of nitrogen mixed), enters the gas-liquid separator 6-2 through the stop valve 6-1, nitrogen enters the raffinate separation subsystem 7 from the upper inlet through the stop valve 6-3 and the one-way valve 6-4, and the subcritical carbon dioxide enters the extract separation unit 8 from the lower part of the gas-liquid separator 6-2.

[0056] The raffinate separation unit 7 is composed of a stop valve 7-1, a gas-solid separator 7-2, a stop valve 7-3, a one-way valve 7-4, a gate valve 7-5, a residue storage tank 7-6, a stop valve 7-7, a one-way valve 7-8, and a discharge valve 7-9. After the extraction of the materials in the extractor 4-1-1 to 4-1-N is completed, the subcritical carbon dioxide reaching the saturated state is sent into the extract pressure reduction separation unit 8 through the outlet valve, at this time, the raffinate is still present in the extractor, the discharge valve 4-10-1 to 4-10-N is opened, and the raffinate enters the raffinate separation subsystem. The raffinate enters the gas-solid separator 7-2 through the stop valve 7-1, nitrogen is recycled to the nitrogen pressurization jetting subsystem 3 from the upper outlet through the stop valve 7-3 and the one-way valve 7-4, the raffinate passes through the gate valve 7-5 and enters the residue storage tank 7-6 through the lower outlet of the gas-solid separator 7-2, the residue is discharged through the discharge valve 7-9, and a small amount of gas separated from the residue storage tank 7-6 can be introduced into the storage tank 2-9 for evacuation.

[0057] The extract depressurization separation unit 8 is composed of a stop valve 8-1, a heat exchanger 8-2, a pressure regulating valve 8-3, a heater 8-4, a depressurization kettle 8-5, a pressure regulating valve 8-6, a heater 8-7, a separation kettle 8-8, a discharge valve 8-9, a discharge valve 8-10, a vent valve 8-11, and a stop valve 8-12. The subcritical carbon dioxide from the bottom of the extractor reaching a saturated state enters the extract depressurization separation unit 8 via the gas-liquid separation unit 6. After being preheated by the waste heat generated by the refrigeration in the subcritical carbon dioxide refrigeration pressurization subsystem 1, the subcritical carbon dioxide enters the depressurization separation unit 8. In order to prevent the temperature from being too low during the throttling depressurization process and to prevent icing, the extract depressurization separation unit 8 is designed to have two throttling depressurization processes. First, the subcritical carbon dioxide carrying the extraction solute enters the depressurization kettle 8-5 via the stop valve 8-1, the heat exchanger 8-2, the pressure regulating valve 8-3, and the heater 8-4, and then enters the separation kettle 8-8 via the pressure regulating valve 8-6 and the heater 8-7. The extraction solute in the two kettles is discharged through the discharge valves 8-9 and 8-10, and the subcritical carbon dioxide in the separation kettle is phase-changed into a gaseous state to release the extraction solute. The gaseous carbon dioxide is returned to the subcritical carbon dioxide refrigeration pressurization subsystem 1 via the stop valve 8-12 for recycling.

[0058] Based on the above system, the embodiment also provides a method for inflating subcritical carbon dioxide fluidization continuous extraction and separation, and the steps are as follows:

[0059] (1) System venting:

[0060] First, the subcritical carbon dioxide fluidization continuous extraction subsystem, the material feeding subsystem, the gas-liquid separation unit, and the extract depressurization separation unit are vented. The gaseous carbon dioxide in the carbon dioxide storage tank 1-1 is vented via the stop valve 1-2, the cooler 1-3, the stop valve 1-4, the control valve 1-6, the thermostat 1-7, the one-way valve 1-8, and then is divided into two paths. One path enters the extractors 4-1-1 to 4-1-N via the stop valve 4-9-1 to the stop valve 4-9-N, and the other path enters the feeding tank 2-6 via the stop valve 2-1, the subcritical carbon dioxide storage tank 2-2, and the stop valve 2-3.

[0061] Wherein one way through the stop valve 4-9-1 to the stop valve 4-9-N into the extractor 4-1-1 to the extractor 4-1-N, close the stop valve 4-3-1 to the stop valve 4-3-N, and the stop valve 4-6-1 to the stop valve 4-6-N, the stop valve 4-7-1 to the stop valve 4-7-N and the discharge valve 4-10-1 to the discharge valve 4-10-N above the extractor 4-1-1 to the extractor 4-1-N, open the stop valve 4-9-1 to the stop valve 4-9-N, make the gaseous carbon dioxide into the extractor 4-1-1 to the extractor 4-1-N, then open the outlet valve 4-8-1 to the outlet valve 4-8-N at the bottom of the extractor, the gaseous carbon dioxide through the stop valve 6-1 into the gas-liquid separator 6-2, close the stop valve 6-3 above the gas-liquid separator 6-2, then the gas from below the gas-liquid separator 6-2, through the stop valve 8-1, heat exchanger 8-2, pressure regulating valve 8-3, heater 8-4 into the decompression kettle 8-5, again through the pressure regulating valve 8-6, heater 8-7 into the separation kettle 8-8, through the evacuation valve 8-11 to be evacuated, at this time the discharge valve 8-9, the discharge valve 8-10 and the stop valve 8-12 should be closed.

[0062] Firstly, the measured material is filled into the storage tank 2-9 by the feeding valve 2-11, and then the feeding valve 2-11 is closed. Another way through the stop valve 2-1, the subcritical carbon dioxide storage tank 2-2, the stop valve 2-3, the control valve 2-5 into the feeding tank 2-6. Then in two ways, one way to open the balance valve 2-7 and the gate valve 2-8, the storage tank 2-9 falls into the feeding tank 2-6 by the gate valve 2-8 by gravity, the gate valve 2-8 is closed, and then the evacuation valve 2-10 is opened to be evacuated. Another way through the stop valve 2-12, the stop valve 3-10, the stop valve 3-11 and the stop valve 4-5-1 to the stop valve 4-5-N into the extractor 4-1-1 to the extractor 4-1-N. Similarly, the stop valve 4-3-1 to the stop valve 4-3-N, the stop valve 4-6-1 to the stop valve 4-6-N, the stop valve 4-7-1 to the stop valve 4-7-N and the discharge valve 4-10-1 to the discharge valve 4-10-N are closed, and then the outlet valve 4-8-1 to the outlet valve 4-8-N at the bottom of the extractor is opened, the gaseous carbon dioxide through the stop valve 6-1 into the gas-liquid separator 6-2, the stop valve 6-3 above the gas-liquid separator 6-2 is closed, then the gas from below the gas-liquid separator 6-2, through the stop valve 8-1, heat exchanger 8-2, pressure regulating valve 8-3, heater 8-4 into the decompression kettle 8-5, again through the pressure regulating valve 8-6, heater 8-7 into the separation kettle 8-8, through the evacuation valve 8-11 to be evacuated, at this time the discharge valve 8-9, the discharge valve 8-10 and the stop valve 8-12 should be closed.

[0063] Secondly, the nitrogen pressurized jet subsystem, nitrogen pressurized circulating subsystem empty. Open nitrogen cylinder 3-1, stop valve 3-2 to make the gas into the nitrogen storage tank 3-3, the nitrogen in the nitrogen storage tank 3-3 through the stop valve 3-5, nitrogen buffer tank 3-6 from the emptying valve 3-7 discharge; the other way through the stop valve 3-12, check valve 3-13, stop valve 4-6-1 to stop valve 4-6-N into the extractor 4-1-1 to extractor 4-1-N, then through the demister 4-2-1 to demister 4-2-N, stop valve 4-3-1 to stop valve 4-3-N, check valve 4-4-1 to check valve 4-4-N, stop valve 5-2, stop valve 5-3 into the nitrogen storage tank 5-4, through the emptying valve 5-5 discharge.

[0064] Finally, the raffinate separation unit is emptied. Open nitrogen cylinder 3-1, nitrogen through stop valve 3-2 into the nitrogen storage tank 3-3, then through stop valve 3-12, check valve 3-13, stop valve 4-6-1 to stop valve 4-6-N into the extractor 4-1-1 to extractor 4-1-N, at this time only open discharge valve 4-10-1 to discharge valve 4-10-N, the rest of the valve is closed. Nitrogen through the discharge valve 4-10-1 to discharge valve 4-10-N into the raffinate separation subsystem 7, through the stop valve 7-1 into the gas-solid separator 7-2, nitrogen from the top through the stop valve 7-3, check valve 7-4, stop valve 3-17 into the nitrogen buffer tank 3-15, through the emptying valve 3-16 to empty. Thus, the system is empty.

[0065] (2) system feeding:

[0066] The first time, the material to be extracted through the feed valve 2-11 into the storage tank 2-9, the air in which is discharged from the emptying valve 2-10 using carbon dioxide cylinder 1-1. The material to be extracted in the storage tank 2-9 is weighed and gravity fed through the gate valve 2-8 into the feed tank 2-6. After the material to be extracted in the feed tank 2-6 and the subcritical carbon dioxide are soaked for a period of time, they are pumped out by the jet pump and sprayed into the extractor. To avoid vacuumizing the feed tank, open the pressurizing pump 2-4 to send the subcritical carbon dioxide fluid into the feed tank. The subsequent feeding is balanced by the balance valve 2-7 between the storage tank 2-9 and the feed tank 2-6, then the gate valve 2-8 is opened and gravity is used to load again. After the loading is completed, the air in it is discharged from the emptying valve 2-10 using the gas in the storage tank 7-6, and the re-feeding process is completed.

[0067] (3) nitrogen jet:

[0068] Close the stop valve 3-12, the balance valve 3-14, open the nitrogen cylinder 3-1, the stop valve 3-2, the nitrogen through the nitrogen storage tank 3-3, the compressor 3-4, the nitrogen buffer tank 3-6 and the stop valve 3-8, the nitrogen compressed by the compressor is injected into the extractor 4-1-1 to the extractor 4-1-N from the jet pump 3-9, before that, open the stop valve 3-11 and the stop valve 4-5-1 to the stop valve 4-5-N. From the nitrogen storage tank 3-3 through the stop valve 3-12, the check valve 3-13, the stop valve 4-6-1 to the stop valve 4-6-N into the extractor 4-1-1 to the extractor 4-1-N, to blow the raffinate into the raffinate separation unit 7, and then the separated nitrogen is discharged into the nitrogen buffer tank 3-15 through the stop valve 3-17, and then returned to the nitrogen storage tank 3-3 through the balance valve 3-14, for recycling.

[0069] (4) Extraction of the material:

[0070] Close the stop valve 3-11, the inlet valve 4-5-1 to the inlet valve 4-5-N, the stop valve 4-6-1 to the stop valve 4-6-N, the outlet valve 4-8-1 to the outlet valve 4-8-N, the discharge valve 4-10-1 to the stop valve 4-10-N and the stop valve 5-2, open the stop valve 4-3-1 to the stop valve 4-3-N, the compressor 5-1, the stop valve 5-3, the stop valve 5-6 and the stop valve 4-7-1 to the stop valve 4-7-N. At this time, the nitrogen from the top of the extractor through the demister 4-2-1 to the demister 4-2-N, the stop valve 4-3-1 to the stop valve 4-3-N, the check valve 4-4-1 to the check valve 4-4-N, the compressor 5-1, the stop valve 5-3, the nitrogen storage tank 5-4, the stop valve 5-6, the stop valve 4-7-1 to the stop valve 4-7-N is returned to the extractor, and the mixture of the material and the subcritical carbon dioxide fluid is circulated and blown by the nitrogen to form a fluidized extraction. During the extraction process, the stop valve 4-9-1 to the stop valve 4-9-N can be occasionally opened to supplement fresh subcritical carbon dioxide fluid to ensure that the extraction can reach or approach saturation. Then stop the compressor 5-1, so that the nitrogen no longer circulates, the extraction is completed, the stop valve 4-3-1 to the stop valve 4-3-N and the stop valve 4-7-1 to the stop valve 4-7-N are closed, and the outlet valve 4-8-1 to the outlet valve 4-8-N is opened to discharge the subcritical carbon dioxide in the extractor to the pressure reduction separation subsystem for separation.

[0071] (5) Pressure reduction separation of the solute:

[0072] After the extraction of the material is completed, the stop valves 4-3-1 to 4-3-N and 4-7-1 to 4-7-N are closed, and the outlet valves 4-8-1 to 4-8-N are opened, so that the subcritical carbon dioxide in the extractor is discharged to the gas-liquid separator set 6. The subcritical carbon dioxide fluid carrying the solute enters the gas-liquid separator 6-2 through the stop valve 6-1, and when the gas carrying the nitrogen is discharged, the nitrogen enters the raffinate separator set 7 through the stop valve 6-3 and the one-way valve 6-4, while the subcritical carbon dioxide fluid carrying the solute enters the extract depressurization separator set 8 from the lower outlet. The stop valve 8-1 is opened, and the subcritical carbon dioxide fluid carrying the solute is heat-exchanged through the heat exchanger 8-2, and then enters the depressurization kettle 8-5 with the heater 8-4 through the pressure regulating valve 8-3, and then enters the separation kettle 8-8 with the heater 8-7 through the pressure regulating valve 8-6, and after two throttling depressurizations, the subcritical carbon dioxide is phase changed into gaseous carbon dioxide, and the solute dissolved therein is released, and the gaseous carbon dioxide is recycled to the refrigeration pressurization circulation system through the stop valve 8-12. At this time, the pressure in the extractor is reduced to about 6 MPa.

[0073] (6) Separation of the raffinate:

[0074] After the extraction of the material is completed, the density of the raffinate in the extractor is greatly reduced, and is lower than the density of the subcritical carbon dioxide, but can be higher than the density of the nitrogen. At this time, the raffinate can float on the top of the filter screen in the extractor, or can sink on the lower filter screen in the extractor. Since the pressure in the extractor has been reduced to about 6 MPa at this time, the stop valve 3-2 is opened, so that the nitrogen enters the nitrogen storage tank 3-3, and then the stop valve 3-12, the one-way valve 3-13, and the stop valves 4-6-1 to 4-6-N are opened, and the high-pressure nitrogen is used to blow the raffinate into the raffinate separation system 7; or the nitrogen in the nitrogen storage tank 5-4 is used to blow the raffinate into the raffinate separation set 7 through the stop valve 5-6 and the stop valves 4-6-1 to 4-6-N. The raffinate enters the gas-solid separator 7-2 through the discharge valves 4-10-1 to 4-10-N and the stop valve 7-1, the nitrogen passes through the upper outlet, enters the nitrogen buffer tank 3-15 through the stop valve 7-3 and the one-way valve 7-4, and then is recycled to the nitrogen storage tank 3-3 through the balance valve 3-14; and the raffinate passes through the lower outlet, enters the residue storage tank 7-6 through the gate valve 7-5, and the residue can be discharged through the discharge valve 7-9, and a small amount of gas containing therein enters the storage tank 2-9 through the stop valve 7-7 and the one-way valve 7-8, and can be used for subsequent emptying.

[0075] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the principles and technical scope of the present application shall fall into the scope of the present application.

Claims

1. A gas-filled subcritical carbon dioxide fluidized bed continuous extraction and separation system, characterized in that, The subcritical carbon dioxide refrigeration pressurization circulation subsystem, the material feeding subsystem, the nitrogen pressurization jet flow subsystem, the subcritical carbon dioxide fluidization continuous extraction subsystem and the pressure reduction separation subsystem; The subcritical carbon dioxide fluidization continuous extraction subsystem comprises a subcritical carbon dioxide fluidization continuous extractor unit and a nitrogen pressurization circulation unit, the subcritical carbon dioxide fluidization continuous extractor unit comprises one or more extractors, the internal space of the extractor is divided into an upper region and a lower region by a filter screen, the upper region of the filter screen is arranged with a nitrogen inlet and a nitrogen outlet, the lower region of the filter screen is arranged with a material inlet and a subcritical carbon dioxide inlet, the bottom of the extractor is provided with a nitrogen inlet, a raffinate outlet and a subcritical carbon dioxide outlet; the nitrogen inlet is connected with the nitrogen pressurization circulation unit and the nitrogen pressurization jet flow subsystem respectively, the nitrogen outlet is connected with the nitrogen pressurization circulation unit, the subcritical carbon dioxide outlet is connected with the pressure reduction separation subsystem, the nitrogen pressurization circulation unit blows high-pressure nitrogen into the extractor to realize fluidization mixing of the subcritical carbon dioxide extractant and the material to be extracted in the extractor, and the subcritical carbon dioxide extraction reaches or approaches saturation and then the subcritical carbon dioxide extractant is discharged from the extractor; The subcritical carbon dioxide refrigeration pressurization circulation subsystem pressurizes the carbon dioxide in the system to a subcritical state through cooling and liquefaction, and supplies the material feeding subsystem and the subcritical carbon dioxide fluidization continuous extraction subsystem; The nitrogen pressurization jet flow subsystem uses the high-pressure nitrogen circulating in the system to send the mixture of the material to be extracted and the subcritical carbon dioxide into the subcritical carbon dioxide fluidization continuous extraction subsystem.

2. The pneumatic subcritical carbon dioxide fluidized continuous extraction separation system of claim 1 wherein, The subcritical carbon dioxide refrigeration pressurization circulation subsystem comprises a carbon dioxide storage tank, a cooler, a pressurization pump and a thermostat connected in sequence; the carbon dioxide separated by the pressure reduction separation subsystem is cooled in the cooler.

3. The inflatable subcritical carbon dioxide fluidized continuous extraction separation system of claim 1 wherein, The material feeding subsystem comprises a storage tank and a feeding tank connected in sequence, the storage tank stores the material to be extracted, and the material to be extracted in the storage tank enters the feeding tank by gravity; and the material feeding subsystem further comprises a subcritical carbon dioxide storage tank and a pressurization pump connected in sequence, the pressurization pump is connected with the feeding tank, and the subcritical carbon dioxide extractant and the material to be extracted are mixed in the feeding tank.

4. The inflatable subcritical carbon dioxide fluidized continuous extraction separation system of claim 1 wherein, The nitrogen pressurization jet flow subsystem comprises a nitrogen storage tank, a compressor, a first nitrogen buffer tank and a flow jet pump connected in sequence, the flow jet pump uses high-pressure nitrogen to send the mixture of the subcritical carbon dioxide extractant and the material to be extracted in the material feeding subsystem into the extractor through the material inlet; the nitrogen storage tank is connected with a nitrogen source, and the nitrogen storage tank is connected with the nitrogen inlet of the extractor through a one-way valve.

5. The inflatable subcritical carbon dioxide fluidized extraction separation system of claim 4 wherein, The nitrogen pressurization jet flow subsystem further comprises a second nitrogen buffer tank connected with the nitrogen storage tank, the nitrogen separated by the pressure reduction separation subsystem enters the second nitrogen buffer tank, and then enters the nitrogen storage tank through a pipeline, so that the nitrogen is recycled.

6. The inflatable subcritical carbon dioxide fluidized extraction separation system of claim 1 wherein, The pressure reduction separation subsystem comprises a gas-liquid separation unit, a raffinate separation unit and an extractive pressure reduction separation unit. The gas-liquid separator unit is used for separating subcritical carbon dioxide carrying solutes and nitrogen, and comprises a gas-liquid separator, a subcritical carbon dioxide outlet of an extractor is connected with the gas-liquid separator, separated nitrogen enters a nitrogen pressurized jet subsystem, and separated subcritical carbon dioxide carrying solutes enters a extract pressure reduction separator unit; The raffinate separation unit is used for separating raffinate and nitrogen, and comprises a gas-solid separator and a residue storage tank connected in sequence, a raffinate outlet of the extractor is connected with the gas-solid separator, separated nitrogen is transported to the nitrogen pressurized jet subsystem, and separated raffinate enters the residue storage tank, and a small amount of gas separated from the residue storage tank is introduced into the material feeding subsystem for emptying use; The extract pressure reduction separator unit comprises a heat exchanger, a heater, a pressure reduction kettle and a separation kettle, the heat exchanger is connected with a liquid outlet of the gas-liquid separator, an outlet of the heat exchanger is connected with the first heater, the first heater is connected with the pressure reduction kettle, the pressure reduction kettle is connected with the second heater, the second heater is connected with the separation kettle, and gas in the separation kettle is transported to a subcritical carbon dioxide refrigeration pressurized circulation subsystem.

7. The inflatable subcritical carbon dioxide fluidized extraction separation system of claim 6 wherein, Subcritical carbon dioxide reaching a saturated state at the bottom of the extractor is preheated by the heat exchanger, heated by the heater, and then, in the pressure reduction kettle and the separation kettle, subcritical carbon dioxide carrying solutes is throttled twice to reduce pressure, subcritical carbon dioxide is phase changed into gaseous carbon dioxide, and solutes dissolved in the subcritical carbon dioxide are released, and the gaseous carbon dioxide enters the subcritical carbon dioxide refrigeration pressurized circulation subsystem for recycling.

8. The system of claim 1 wherein the system is a continuous supercritical carbon dioxide fluid extraction system. The nitrogen pressurized circulation unit comprises a nitrogen storage tank and a compressor connected in sequence, the nitrogen storage tank is connected with two nitrogen inlets of the extractor, and a nitrogen outlet of the extractor is connected with the compressor; During the extraction process, high-pressure nitrogen enters the extractor from the nitrogen inlet at the upper region of the filter screen, blows the material to be extracted, and forms fluidization to accelerate the extraction, and the nitrogen enters the compressor from the nitrogen outlet at the upper region of the filter screen for recycling; after the extraction is completed, high-pressure nitrogen enters the extractor from the nitrogen inlet at the upper region of the filter screen, and the raffinate is blown into the pressure reduction separation subsystem through the raffinate outlet.

9. A continuous separation process by pneumatic subcritical carbon dioxide fluidization extraction, characterized in that, The inflatable subcritical carbon dioxide fluidization continuous extraction and separation system of any one of claims 1-8 comprises the following steps: The material to be extracted is stored in the material feeding subsystem, the material to be extracted and the subcritical carbon dioxide mixture are injected into the extractor by the jet pump, the nitrogen pressurized jet subsystem and the nitrogen pressurized circulation unit are opened, nitrogen is injected into the extractor, the nitrogen is circulated between the extractor and the nitrogen pressurized circulation unit to blow the material to be extracted and the subcritical carbon dioxide mixture in the extractor to form fluidization extraction, until the subcritical carbon dioxide in the extractor reaches or approaches a saturated state, the self-circulation of the nitrogen in the extractor is stopped, and the subcritical carbon dioxide in the extractor is discharged to the pressure reduction separation subsystem for separation. After the extraction of the material is completed, the subcritical carbon dioxide carrying the solute enters the gas-liquid separation unit through the subcritical carbon dioxide outlet, and after the separation of the nitrogen gas, the subcritical carbon dioxide carrying the solute enters the extract depressurization separation unit, and after two throttling depressurizations, the subcritical carbon dioxide is phase changed into gaseous carbon dioxide, and the solute dissolved therein is released, and the gaseous carbon dioxide reenters the subcritical carbon dioxide refrigeration pressurization circulation subsystem for recycling; After the extraction of the material is completed, the nitrogen pressurized jet subsystem is opened, high-pressure nitrogen is input into the extractor through the nitrogen inlet at the upper part of the extractor filter screen, the raffinate is blown into the raffinate separation unit by the high-pressure nitrogen, the separated nitrogen enters the nitrogen pressurized jet subsystem, and the separated raffinate enters the residue storage tank, and a small amount of gas contained in the residue storage tank enters the material storage tank of the material feeding subsystem for subsequent emptying.

10. The process of claim 9 wherein the process is a pneumatic subcritical carbon dioxide fluidization continuous extraction separation process, characterized by, The subcritical carbon dioxide fluidized continuous extractor unit is composed of one or more extractors, and the continuous extraction process is realized by the sequential feeding and discharging of the multiple extractors; Or, during the extraction process, the subcritical carbon dioxide refrigeration pressurization circulation subsystem is used to supplement the subcritical carbon dioxide fluid into the extractor, so as to ensure that the extraction can reach or approach saturation; Or, after the extraction of the material is completed, the nitrogen pressurized circulation unit is opened, high-pressure nitrogen is input into the extractor through the material inlet of the extractor, and the raffinate is blown into the raffinate separation unit by the high-pressure nitrogen.

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