A continuous extraction separation system and process with pressure build-up and release, self-balancing and back extraction

Abstract

This invention discloses a continuous extraction and separation system and process with self-balancing pressure boosting and depressurization and backpressure, belonging to the field of continuous production technology of fluid-solid extraction and separation. It includes a continuous extraction subsystem connected to an isobaric separation subsystem and / or a depressurization separation subsystem, and connected to a constant pressure circulation subsystem and / or a pressurization circulation subsystem. The constant pressure circulation subsystem and / or the pressurization circulation subsystem are connected to an extraction fluid storage subsystem and an isobaric separation subsystem and / or a depressurization separation subsystem. The continuous extraction subsystem includes an extractor; the extractor's extraction fluid inlet is connected to a balance and pressure-reducing pipe via a balance and pressure-reducing valve; the extractor's extraction fluid outlet is connected to a vent and backpressure pipe via a vent and backpressure valve; the vent and backpressure pipe is connected to the atmosphere via a main vent valve; the balance and pressure-reducing pipe is connected to a backpressure condenser via a pressure-reducing valve; the backpressure condenser is connected to the inlet of a pressure-reducing pump; and the pressure-reducing pump outlet is connected to the vent and backpressure pipe.

Description

Technical Field

[0001] This invention belongs to the field of continuous production technology of fluid-solid extraction and separation, specifically relating to a continuous extraction and separation system and process with pressure boosting, depressurization self-balancing and extraction. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Supercritical or subcritical fluid extraction of solid materials is a green process industrial production technology that is gaining widespread application. However, existing technologies mostly use intermittent devices with quick-start structures. The frequent start-up of the device causes frequent changes in the working fluid pressure from high pressure to medium pressure to atmospheric pressure, resulting in high power consumption, poor safety and reliability, and low production efficiency, which seriously restricts the promotion and application of these new technologies.

[0004] Chinese patents CN110237561B (titled "A Supercritical Fluid Continuous Extraction and Separation Device System and Extraction and Separation Process") and CN110152350B (titled "A Subcritical Fluid Continuous Isobaric Extraction and Separation Device System and Extraction and Separation Process") disclose invention patents. The main component of the invented device system—the continuous extraction subsystem—consists of a hopper, an extraction cylinder, a loading end of the extraction cylinder, a loading end locking device, a loading hydraulic cylinder, an unloading end of the extraction cylinder, an unloading end locking device, an unloading hydraulic cylinder, a fluid inlet pipe assembly, and a fluid outlet pipe assembly. The extraction cylinder is filled with a hopper, which is a bottomed cup-shaped cylinder. The bottom ring of the hopper is equipped with a sealing structure, which seals the hopper with the inner cavity of the extraction cylinder. This forms a step-by-step pressure increase zone, extraction pressure zone, and step-by-step pressure decrease zone between the hoppers along the axis of the extraction cylinder. The step-by-step pressure increase and decrease zones with the same pressure are connected by a connecting pipe to achieve pressure balance. When the continuous extraction subsystem is working, under the action of the loading and unloading hydraulic cylinders, each hopper enters from one end of the extraction cylinder and exits from the other end in a linear motion, passing through each pressure increase zone, extraction pressure zone, and pressure decrease zone one by one, achieving a step-by-step pressure increase and decrease self-balancing effect. However, because the loading and unloading hydraulic cylinders are required to drive them, their energy loss is still relatively large, and the sealing requirements are high, wear is severe, and the seals need to be replaced frequently.

[0005] Chinese Patent Publication No. CN114263780A, entitled "A Pressure Gradual Increase and Decrease Self-Balancing High-Pressure or Ultra-High-Pressure Valve Switching System," describes a switching system comprising a supply valve, a supply pipe, a return valve, a return pipe, a pressure balancing valve, a pressure balancing pipe, a venting and backpressure valve, a venting pipe, and a container. The container serves as the site for fluid-solid extraction, separation, sterilization, or reaction. The supply valve opens or closes the flow of pressurized fluid into the container. The supply pipe connects the pressurized fluid source to the supply valve. The return valve opens or closes the flow of pressurized fluid out of the container. The return pipe connects the return valve to the pressurized fluid source. There may be one or more pressurized fluid sources, and the number of supply pipes or return pipes is equal to the number of pressurized fluid sources. The pressure balancing valve balances the pressures of the two containers at the required pressure level, and is either pneumatic or electrically controlled. The balancing process brings the pressures of the two containers to the desired balanced pressure level. However, the step-by-step pressurization container and the step-by-step depressurization container of this invention operate independently. In addition to the non-working container required for loading and unloading, it requires 2 times the number of step-by-step pressurization stages minus 1 container that alternates to be in a non-working state, which increases the number of ineffective pressurization and depressurization containers and equipment investment. In addition, the unloading container needs to release pressure fluid at one-third of the working pressure of the step-by-step pressurization stages, which makes the system unnecessarily complex.

[0006] Chinese patent application publication number CN116688559A, entitled "A Multi-State Fluid Continuous Extraction Isobaric / Depressurized Separation System and Extraction Separation Process," comprises a continuous extraction subsystem with progressively self-balancing pressure increase and decrease switching, at least one isobaric separation subsystem and / or at least one depressurized separation subsystem, and a constant-pressure circulation subsystem equal in number to the isobaric separation subsystem and / or a pressurized circulation subsystem equal in number to the depressurized separation subsystem. The continuous extraction subsystem is connected to the isobaric separation subsystem and / or the depressurized separation subsystem, the isobaric separation subsystem is connected to the constant-pressure circulation subsystem, and the depressurized separation subsystem is connected to the pressurized circulation subsystem. The constant pressure circulation subsystem and / or the booster circulation subsystem are connected to the continuous extraction subsystem; the continuous extraction subsystem of the invented system, which features step-by-step self-balancing pressure increase and decrease switching, includes multiple extractors connected in parallel. The extraction fluid inlet of each extractor is connected to the supply pipe via a supply valve and to the balance and vent pipe via a balance valve; the extraction fluid outlet of each extractor is connected to the return pipe via a return valve and to the balance and vent pipe via a vent valve, and the balance and vent pipe is connected to the atmosphere via a main vent valve; the number of supply pipes and return pipes is the same, and the same as the number of constant pressure circulation subsystems or booster circulation subsystems; the number of supply valves, return valves, balance valves, and vent valves is the same as the number of extractors. Although this invention overcomes the problem of the independent operation of the step-up and step-down extractors when the loading and unloading extractors in the continuous extraction subsystem require pressure to rise and fall in stages for self-balancing, it still requires extractors in non-extraction working state, in addition to the extractors required for loading and unloading, to alternate between non-extraction working state, with the number of extractors equal to the number of step-up and step-down pressure stages. This still requires the number of ineffective pressure-rising and depressurizing containers and equipment investment. At the same time, the unloading extractor still needs to release the extraction fluid at one-third of the extraction pressure of the step-up and step-down pressure stages, making the system unnecessarily complex. In addition, the system's cold and hot energy utilization is insufficient, resulting in high energy consumption. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a continuous extraction and separation system and process with self-balancing pressure boosting and depressurization plus extraction. The continuous extraction subsystem of this system achieves the effects of isobaric separation in continuous fluid-solid extraction or depressurized separation in continuous fluid-solid extraction.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0009] In a first aspect, the present invention provides a continuous extraction and separation system with self-balancing pressure boosting and depressurization plus extraction, comprising a continuous extraction subsystem, the continuous extraction subsystem being connected to an isobaric separation subsystem and / or a depressurization separation subsystem, the continuous extraction subsystem being connected to a constant pressure circulation subsystem and / or a pressurization circulation subsystem, and the constant pressure circulation subsystem and / or the pressurization circulation subsystem being connected to an extraction fluid storage subsystem, an isobaric separation subsystem and / or a depressurization separation subsystem;

[0010] The continuous extraction subsystem includes multiple extractors connected in parallel. The extraction fluid inlet of the extractor is connected to the balance and pressure-suction pipe through a balance and pressure-suction valve, and the extraction fluid outlet of the extractor is connected to the vent and back pressure pipe through a vent and back pressure valve. The vent and back pressure pipe is connected to the atmosphere through a main vent valve.

[0011] The balancing and pressure-extracting pipe is connected to the return condenser via a pressure-extracting valve. The return condenser is connected to the inlet of the pressure-extracting pump, and the outlet of the pressure-extracting pump is connected to the venting and backpressure pipe via a check valve. By opening the balancing and pressure-extracting valves of the finished extractor and the newly installed extractor, the extractant fluid from the finished extractor is balanced to the newly installed extractor. Then, by opening the balancing and pressure-extracting valves of the finished extractor and the venting and backpressure valves of the newly installed extractor, the pressure-extracting pump draws the remaining extractant fluid from the finished extractor into the newly installed extractor, thus switching the process.

[0012] The extraction fluid can be a supercritical fluid under at least one operating condition or / and a subcritical fluid under at least one operating condition.

[0013] As a further technical solution, the extraction fluid inlet of the extractor is connected to the supply pipe through a supply valve; the extraction fluid outlet of the extractor is connected to the return pipe through a return valve; the isobaric separation subsystem and / or the depressurization separation subsystem are both connected to the continuous extraction subsystem through corresponding return pipes; the isobaric separation subsystem is connected to the constant pressure circulation subsystem; the depressurization separation subsystem is connected to the pressurization circulation subsystem; and the constant pressure circulation subsystem and / or the pressurization circulation subsystem are both connected to the continuous extraction subsystem through corresponding supply pipes.

[0014] As a further technical solution, the isobaric separation subsystem is a single-stage or multi-stage separation system, which includes an isobaric separation intermediate heat exchanger, an isobaric separator, and an isobaric separation heat pump connected in series. The isobaric separation heat pump includes a compressor, an expansion valve, an evaporator, and a condenser. The cold side of the condenser of the same stage is connected to the isobaric separator, and the extract outlet of the isobaric separator is equipped with a discharge valve.

[0015] The isobaric separation heat pump condenser and the number of isobaric separator stages are the same as the number of isobaric separation stages. The cold-side fluid inlet of the intermediate heat exchanger of the isobaric separation is connected to the return pipe. The cold-side fluid outlet of the intermediate heat exchanger of the isobaric separation is connected to the cold-side inlet of the first-stage condenser. The extraction fluid outlet of the last stage isobaric separator is connected to the hot-side fluid inlet of the intermediate heat exchanger of the isobaric separation. The hot-side fluid outlet of the intermediate heat exchanger of the isobaric separation is connected to the hot-side inlet of the heat pump evaporator.

[0016] In an isobaric separation heat pump, the hot side of the condenser of adjacent stages is connected, the hot side of the first stage condenser is connected to the cold side of the evaporator, and an expansion valve is installed between the two. The cold side of the evaporator is connected to the compressor, and the compressor is connected to the hot side of the last stage condenser.

[0017] The constant pressure circulation subsystem includes a constant pressure circulation heater, the outlet of which is connected to the supply pipe, the inlet of which is connected to the outlet of the circulation pump, the inlet of which is connected to the outlet of the one-way valve, and the inlet of the circulation pump is connected to the hot side outlet of the evaporator of the isobaric separation heat pump.

[0018] As a further technical solution, the pressure reduction separation subsystem is a supercritical fluid pressure reduction separation subsystem; the pressure reduction separation subsystem is a single-stage or multi-stage separation, which includes a pressure reduction separation intermediate heat exchanger, a pressure reduction separator, a pressure regulating valve and a pressure reduction separation heat pump connected in series. The pressure reduction separation heat pump includes a compressor, an expansion valve, an evaporator and a condenser. The pressure regulating valve, the cold side of the condenser and the pressure reduction separator of the same stage are connected in sequence. The extract outlet of the pressure reduction separator is equipped with a discharge valve.

[0019] The pressure regulating valve, the pressure reducing separation heat pump condenser, and the pressure reducing separator have the same number of stages as the pressure reducing separation stage. The inlet of the first-stage pressure regulating valve is connected to the return pipe. The extraction fluid outlet of the last-stage pressure reducing separator is connected to the hot-side fluid inlet of the intermediate heat exchanger of the pressure reducing separation. The hot-side fluid outlet of the intermediate heat exchanger of the pressure reducing separation is connected to the hot-side inlet of the evaporator of the pressure reducing separation heat pump.

[0020] In a step-down separation heat pump, the hot side of the adjacent condensers is connected, the hot side of the first-stage condenser is connected to the cold side of the evaporator, and an expansion valve is installed between the two. The cold side of the evaporator is connected to the compressor, and the hot side of the last-stage condenser is connected to the compressor.

[0021] The pressurization circulation subsystem is a supercritical fluid pressurization circulation subsystem; the pressurization circulation subsystem includes a pressurization circulation heater, the outlet of which is connected to the supply pipe, the inlet of which is connected to the cold-side fluid outlet of the pressure-reducing separation intermediate heat exchanger, the cold-side fluid inlet of the pressure-reducing separation intermediate heat exchanger is connected to the outlet of the pressurization pump, the inlet of which is connected to the outlet of the one-way valve, and the inlet of which is connected to the hot-side outlet of the pressure-reducing separation heat pump evaporator.

[0022] As a further technical solution, the pressure reduction separation subsystem is a subcritical fluid pressure reduction separation subsystem; the pressure reduction separation subsystem is a single-stage or multi-stage separation, which includes a pressure reduction separation intermediate heat exchanger, a pressure reduction separator, a pressure regulating valve, and a pressure reduction separation heat pump connected in series. The pressure reduction separation heat pump includes a compressor, an expansion valve, an evaporator, and a condenser. The pressure regulating valve, the cold side of the condenser, and the pressure reduction separator of the same stage are connected in sequence. The extract outlet of the pressure reduction separator is equipped with a discharge valve.

[0023] The pressure regulating valve, the pressure reducing separation heat pump condenser, and the pressure reducing separator have the same number of stages as the pressure reducing separation stage. The inlet of the first-stage pressure regulating valve is connected to the return pipe. The cold side of the pressure reducing separation intermediate heat exchanger is connected between the first-stage pressure regulating valve and the cold side of the first-stage condenser. The extraction fluid outlet of the last-stage pressure reducing separator is connected to the hot-side fluid inlet of the pressure reducing separation intermediate heat exchanger. The hot-side fluid outlet of the pressure reducing separation intermediate heat exchanger is connected to the hot-side inlet of the evaporator.

[0024] In a step-down separation heat pump, the hot side of the adjacent condensers is connected, the hot side of the first-stage condenser is connected to the cold side of the evaporator, and an expansion valve is installed between the two. The cold side of the evaporator is connected to the compressor, and the hot side of the last-stage condenser is connected to the compressor.

[0025] The pressurization circulation subsystem is a subcritical fluid pressurization circulation subsystem; the pressurization circulation subsystem includes a pressurization circulation heater, the outlet of which is connected to the supply pipe, the inlet of which is connected to the outlet of the pressurization circulation heater, the inlet of which is connected to the outlet of the pressurization pump, and the inlet of the pressurization pump is connected to the outlet of the one-way valve, and the inlet of the pressurization pump is connected to the hot side outlet of the evaporator of the pressure-reducing separation heat pump.

[0026] As a further technical solution, the extraction fluid storage subsystem includes an extraction fluid storage tank, the outlet of which is connected to the inlet of the storage condenser, the outlet of which is connected to the inlet of the pressure boosting pump, and the outlet of the pressure boosting pump is connected to the one-way valve inlet of the constant pressure circulation subsystem and / or the pressure boosting circulation subsystem.

[0027] Secondly, the present invention also provides an extraction separation process for the continuous extraction separation system with self-balancing pressure boosting and depressurization plus evacuation as described above, comprising the following steps:

[0028] Subcritical fluid continuous extraction and isobaric separation process: The extractant is in a subcritical state; after the extractant from the extractant storage subsystem completes the condensation and pressurization process, it enters the constant pressure circulation subsystem circulation pump and flows through the constant pressure circulation heater, sequentially through the continuous extraction subsystem, the cold side of the isobaric separation intermediate heat exchanger, the isobaric separation subsystem, the hot side of the isobaric separation intermediate heat exchanger, and the hot side of the isobaric separation heat pump evaporator, before returning to the constant pressure circulation subsystem circulation pump to complete the circulation operation;

[0029] The extraction extractor switches a balancing and pressure-extraction valve, allowing the extractant fluid to be balanced through the balancing and pressure-extraction pipe to the newly installed extractant. Then, through the balancing and pressure-extraction valve, balancing and pressure-extraction pipe, pressure-extraction valve, return condenser, pressure pump, check valve, vent and back pressure pipe, and vent and back pressure valve, all the remaining extractant fluid after balancing in the extraction extractor is returned to the newly installed extractant. Then, the extraction extractor is connected to the atmosphere, completing the unloading of raffinate and loading of extractant. The extractor filled with extractant is filled with extractant fluid during the subsequent self-balancing switching process of the extraction extractor pressure rise and fall, and the remaining extractant fluid after balancing in the subsequent extraction extractor is drawn in by the pressure pump until the near-extraction pressure is reached. The extractant fluid storage subsystem replenishes the extractant fluid to each extraction extractor through a circulation pump, ensuring that the extraction pressure does not decrease due to the addition of extractors near the extraction pressure.

[0030] Thirdly, the present invention also provides an extraction separation process for the continuous extraction separation system with self-balancing pressure boosting and depressurization plus extraction as described above, comprising the following steps:

[0031] Supercritical fluid continuous extraction and depressurization separation process: The extractant is in a supercritical state; after the extractant from the extractant storage subsystem completes the condensation and pressurization process, it enters the pressurization pump of the pressurization circulation subsystem and flows into the cold side of the depressurization separation intermediate heat exchanger. Then, it flows through the pressurization circulation heater, sequentially through the continuous extraction subsystem and the depressurization separation subsystem, and then into the hot side of the depressurization separation intermediate heat exchanger and the hot side of the depressurization separation heat pump evaporator before returning to the pressurization pump to complete the cycle operation.

[0032] The extraction extractor switches a balancing and pressure-extraction valve, allowing the extractant fluid to be balanced through the balancing and pressure-extraction pipe to the newly installed extractant. Then, through the balancing and pressure-extraction valve, balancing and pressure-extraction pipe, pressure-extraction valve, return condenser, pressure pump, check valve, vent and back pressure pipe, and vent and back pressure valve, all the remaining extractant fluid after balancing in the extraction extractor is returned to the newly installed extractant. Then, the extraction extractor is connected to the atmosphere, completing the unloading of raffinate and loading of extractant. The extractor filled with extractant is filled with extractant fluid during the subsequent self-balancing switching process of the extraction extractor pressure rise and fall, and the remaining extractant fluid after balancing in the subsequent extraction extractor is drawn in by the pressure pump until the near-extraction pressure is reached. The extractant fluid storage subsystem replenishes the extractant fluid to each extraction extractor through a circulation pump, ensuring that the extraction pressure does not decrease due to the addition of extractors near the extraction pressure.

[0033] Fourthly, the present invention also provides an extraction separation process for the continuous extraction separation system with self-balancing pressure boosting and depressurization plus extraction as described above, comprising the following steps:

[0034] Subcritical fluid continuous extraction and depressurization separation process: The extractant fluid is in a subcritical state; after the extractant fluid from the extractant fluid storage subsystem completes the condensation and pressurization process, it enters the pressurization pump of the pressurization circulation subsystem and flows into the pressurization circulation heater. It then flows sequentially through the continuous extraction subsystem, the cold side of the depressurization separation intermediate heat exchanger, and the depressurization separation subsystem before flowing into the hot side of the depressurization separation intermediate heat exchanger and the hot side of the depressurization separation heat pump evaporator, before returning to the pressurization pump of the pressurization subsystem to complete the cycle operation.

[0035] The extraction extractor switches a balancing and pressure-extraction valve, allowing the extractant fluid to be balanced through the balancing and pressure-extraction pipe to the newly installed extractant. Then, through the balancing and pressure-extraction valve, balancing and pressure-extraction pipe, pressure-extraction valve, return condenser, pressure-extraction pump, check valve, venting and backpressure pipe, and venting and backpressure valve, all the remaining extractant fluid after balancing in the extraction extractor is returned to the newly installed extractant. Then, it is connected to the atmosphere and the extraction extractor is connected to complete the discharge of raffinate and loading of extractant. The extractor filled with extractant is filled with extractant fluid during the subsequent pressure rise and fall self-balancing switching process of the extraction extractor, and the remaining extractant fluid after balancing in the subsequent extraction extractor is drawn in by the pressure-extraction pump until the near-extraction pressure is reached. The extractant fluid storage subsystem replenishes the extractant fluid to each extraction extractor through a circulation pump to ensure that the extraction pressure does not decrease due to the addition of extractors near the extraction pressure.

[0036] Fifthly, the present invention also provides an extraction and separation process for the continuous extraction and separation system described above, which combines two or more subcritical fluid continuous extraction isobaric separation processes, subcritical fluid continuous extraction depressurization separation processes, or supercritical fluid continuous extraction depressurization separation processes to obtain parallel subcritical fluid continuous extraction isobaric separation combined processes with different extraction pressures, or parallel subcritical fluid continuous extraction depressurization separation combined processes, or parallel supercritical fluid continuous extraction depressurization separation combined processes; or obtain parallel subcritical fluid continuous extraction isobaric separation and subcritical fluid continuous extraction depressurization separation combined processes with the same or different extraction pressures, or parallel subcritical fluid continuous extraction isobaric separation and supercritical fluid continuous extraction depressurization separation combined processes, or parallel subcritical fluid continuous extraction depressurization separation and supercritical fluid continuous extraction depressurization separation combined processes, or parallel subcritical fluid continuous extraction isobaric separation, subcritical fluid continuous extraction depressurization separation and supercritical fluid continuous extraction depressurization separation combined processes.

[0037] The beneficial effects of the present invention are as follows:

[0038] The system of this invention, by adjusting the supply and return valves, venting and backpressure valves, and balancing and pressure-drawing valves of the extraction fluid in different states, forms a continuous extraction subsystem with pressure rise and fall self-balancing and backpressure switching. After extraction, the extractor only needs to establish pressure balance with the newly installed extractor through the balancing and backpressure valve and balancing and backpressure pipe. Then, through the balancing and backpressure valve and balancing and backpressure pipe of the extracted extractor and the venting and backpressure valve and venting and backpressure pipe of the newly installed extractor, the remaining extraction fluid in the extracted extractor is drawn into the newly installed extractor. The number of extractors in the system can be reduced to a minimum of three, and only two extractors need to perform pressure balancing and switching during the extraction process. This reduces the number of extractors that need to be idle due to the step-by-step pressure rise and fall during the extraction process, and reduces equipment investment and operating costs.

[0039] The system of the present invention adds a heat pump with at least one stage of condenser, which makes full use of the heat balance that the extraction fluid needs to be heated before separation or extraction, and needs to be cooled before constant pressure circulation or pressurization circulation, thus greatly reducing system energy consumption and equipment operating costs. Attached Figure Description

[0040] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0041] Figure 1 This is a schematic diagram of a subcritical fluid continuous extraction isobaric separation system with self-balancing pressure rise and fall and pump-back switching operating in a single pressure stage and multiple extractors according to Embodiment 1 of the present invention.

[0042] Figure 2 This is a schematic diagram of a supercritical fluid continuous extraction and depressurization separation system with self-balancing pressure rise and fall and pump-back switching operating in a single pressure stage and multiple extractors according to Embodiment 2 of the present invention.

[0043] Figure 3 This is a schematic diagram of a subcritical fluid continuous extraction and depressurization separation system with self-balancing pressure rise and fall and pump-back switching operating in a single pressure stage and multiple extractors according to Embodiment 3 of the present invention.

[0044] Figure 4 This is a schematic diagram of a combined subcritical fluid continuous extraction isobaric separation and subcritical fluid continuous extraction depressurization separation system with pressure boosting and depressurization self-balancing and pump-back switching, operating in a single pressure stage with multiple extractors, according to Embodiment 4 of the present invention.

[0045] Figure 5 This is a schematic diagram of a combined subcritical fluid continuous extraction isobaric separation and supercritical fluid continuous extraction depressurization separation system with a single pressure stage and multiple extractors operating in Embodiment 5 of the present invention.

[0046] In the diagram: C1, Extraction fluid storage tank; E1, Storage condenser; E2, Retraction condenser; ED1, Pressure-reducing separation heat pump; ED1-1, Primary condenser; ED1-2, Secondary condenser; ED1-3, Evaporator; ED1-4, Expansion valve; ED1-5, Compressor; ED2, Pressure-reducing separation intermediate heat exchanger; ED3, Pressure-boosting circulating heater; EI1, Isobaric separation heat pump; EI1-1, Primary condenser; EI1-2, Secondary condenser; EI1-3, Evaporator; EI1-4, Expansion valve; EI1-5, Compressor; EI2, etc. Intermediate heat exchanger for pressure separation; EI3, constant pressure circulating heater; Et1, extractor 1; Et2, extractor 2; Etn, extractor n; L1, supply pipe 1; L2, return pipe 1; L3, supply pipe 2; L4, return pipe 2; L5, balancing and pressure extraction pipe; L6, venting and backpressure pipe; L7, supply pipe 3; L8, return pipe 3; P1, pressure boosting pump; P2, pressure extraction pump; PI1, circulating pump; PD1, pressurizing pump; SI1, primary isobaric separator; SI2, secondary isobaric separator; SD1, primary pressure reducing separator; SD2, secondary pressure reducing separator. V1, Check Valve 1; V2, Check Valve 2; V3, Check Valve 3; V4, Pressure Reduction Valve; V11, Supply Valve 1-1; V12, Supply Valve 1-2; V1n, Supply Valve 1-n; V21, Return Valve 1-1; V22, Return Valve 1-2; V2n, Return Valve 1-n; V31, Supply Valve 2-1; V32, Supply Valve 2-2; V3n, Supply Valve 2-n; V41, Return Valve 2-1; V42, Return Valve 2-2; V4n, Return Valve 2-n; V51, Balanced Pressure Reduction Valve 1; V52, Balanced Pressure Reduction Valve 2; V5n, Balanced... V61, V62, V6n, V6n, V71, V72, V7n, V81, V82, V8n ...

[0047] The distances or dimensions between parts have been exaggerated to show their positions; the diagram is for illustrative purposes only. Detailed Implementation

[0048] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0049] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is intended to include the plural form as well. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, or / and combinations thereof.

[0050] It should be noted that the extraction fluid of the present invention is replaced with a more general pressure fluid, and the pressure boosting and depressurization self-balancing plus pumping back switching system of the present invention can be used for sterilization or reaction processes.

[0051] It should also be noted that the pressure level values ​​obtained by switching back after balancing are for ideal fluids, while the pressure level values ​​obtained by switching back after balancing for actual fluids will deviate somewhat.

[0052] Example 1:

[0053] In a typical embodiment of the present invention, such as Figure 1 As shown, a subcritical fluid continuous extraction and isobaric separation system with self-balancing pressure rise and fall and pump-back switching, operating with multiple extractors in a single pressure stage, is proposed. It consists of a continuous extraction subsystem, an isobaric separation subsystem, a constant pressure circulation subsystem, and an extraction fluid storage subsystem.

[0054] The continuous extraction subsystem consists of extractor 1Et1, extractor 2Et2 to extractor nEtn, supply pipe 1L1, supply valve 1-1V11, supply valve 1-2V12 to supply valve 1-nV1n, return pipe 1L2, return valve 1-1V21, return valve 1-2V22 to return valve 1-nV2n, balancing and pressure-collecting pipe L5, balancing and pressure-collecting valve 1V51, balancing and pressure-collecting valve 2V52 to balancing and pressure-collecting valve nV5n, venting and backpressure pipe L6, venting and backpressure valve 1V61, venting and backpressure valve 2V62 to venting and backpressure valve nV6n, main venting valve VG1, pressure-collecting valve V4, return condenser E2, pressure-collecting pump P2, and check valve 3V3. The extraction fluid in supply pipe 1L1 and return pipe 1L2 is in a subcritical state.

[0055] Supply valves 1-1V11 and 1-2V12 are connected in parallel to the inlet of supply valve 1-n V1n and connected to supply pipe 1L1. Balance and pressure relief valves 1V51 and 2V52 are connected in parallel to one end of balance and pressure relief valve n V5n and connected to balance and pressure relief pipe L5. Supply valves 1-1V11 and 1-2V12 are connected in parallel to the outlet of supply valve 1-n V1n and the other end of balance and pressure relief valves 1V51 and 2V52 are connected in parallel to the extraction fluid inlet of extractor 1Et1 and extractor 2Et2 to extractor n Etn, respectively.

[0056] The reflux valves 1-1V21 and 1-2V22 to the inlet of reflux valve 1-n V2n and the vent and backpressure valves 1V61 and 2V62 to one end of the vent and backpressure valve n V6n are connected in parallel to the extraction fluid outlets of extractor 1Et1 and extractor 2Et2 to extractor n Etn, respectively. The reflux valves 1-1V21 and 1-2V22 to the outlet of reflux valve 1-n V2n are connected in parallel to the reflux pipe 1L2. The other end of the vent and backpressure valves 1V61 and 2V62 to the vent and backpressure valve n V6n is connected in parallel to the vent and backpressure pipe L6. The vent and backpressure pipe L6 is connected to the atmosphere through the main vent valve VG1.

[0057] The balancing and pressure-reducing pipe L5 is connected to the inlet of the pressure-reducing valve V4. The outlet of the pressure-reducing valve V4 is connected to the inlet of the return condenser E2. The outlet of the return condenser E2 is connected to the inlet of the pressure pump P2. The outlet of the pressure pump P2 is connected to the inlet of the check valve 3V3. The outlet of the check valve 3V3 is connected to the venting and backpressure pipe L6.

[0058] The isobaric separation subsystem can be either a single-stage or two-stage separation. In the single-stage separation, it consists of an intermediate isobaric heat exchanger EI2, a single-stage isobaric separator SI1, an isobaric heat pump EI1, and a single-stage isobaric discharge valve VI1. The isobaric heat pump EI1 consists of a single-stage condenser EI1-1, an evaporator EI1-3, an expansion valve EI1-4, and a compressor EI1-5. In the two-stage separation, in addition to the components of the single-stage separation, there is also a two-stage isobaric separator SI2 and a two-stage isobaric discharge valve VI2. The isobaric heat pump EI1 also has a two-stage condenser EI1-2.

[0059] During primary separation, the cold-side outlet of the isobaric intermediate heat exchanger EI2 is connected to the cold-side inlet of the primary condenser EI1-1 of the isobaric separation heat pump EI1. The cold-side outlet of the primary condenser EI1-1 is connected to the extraction fluid inlet of the primary isobaric separator SI1. The extraction fluid outlet of the primary isobaric separator SI1 is connected to the hot-side inlet of the intermediate heat exchanger EI2. The primary isobaric discharge valve VI1 is connected to the extract outlet of the primary isobaric separator SI1. The hot-side outlet of the intermediate heat exchanger EI2 is connected to the hot-side inlet of the evaporator EI1-3 of the isobaric separation heat pump EI1. The hot side of the primary condenser EI1-1 is connected to the cold side of the evaporator EI1-3. The cold side of the evaporator EI1-3 is connected to the compressor EI1-5. The compressor EI1-5 is reconnected to the hot side of the primary condenser EI1-1. An expansion valve EI1-4 is installed between the hot side of the primary condenser EI1-1 and the cold side of the evaporator EI1-3.

[0060] During the two-stage separation, the cold-side outlet of the isobaric separation intermediate heat exchanger EI2 is connected to the cold-side inlet of the first-stage condenser EI1-1 of the isobaric separation heat pump EI1. The cold-side outlet of the first-stage condenser EI1-1 is connected to the extraction fluid inlet of the first-stage isobaric separator SI1. The extraction fluid outlet of the first-stage isobaric separator SI1 is connected to the cold-side inlet of the second-stage condenser EI1-2 of the isobaric separation heat pump EI1. The cold-side outlet of the second-stage condenser EI1-2 is connected to the extraction fluid inlet of the second-stage isobaric separator SI2. The extraction fluid outlet of the second-stage isobaric separator SI2 is connected to the hot-side inlet of the isobaric separation intermediate heat exchanger EI1. The first-stage isobaric separation discharge valve VI1 is connected to the first-stage isobaric separator S... The extract outlet of I1 is connected, the secondary isobaric separator discharge valve VI2 is connected to the extract outlet of the secondary isobaric separator SI2, the hot side outlet of the intermediate heat exchanger EI2 of the isobaric separator is connected to the hot side inlet of the evaporator EI1-3 of the isobaric separator heat pump EI1; the hot side of the primary condenser EI1-1 is connected to the cold side of the evaporator EI1-3, the cold side of the evaporator EI1-3 is connected to the compressor EI1-5, the compressor EI1-5 is connected to the hot side of the secondary condenser EI1-2, the hot side of the secondary condenser EI1-2 is connected to the hot side of the primary condenser EI1-1, and an expansion valve EI1-4 is installed between the hot side of the primary condenser EI1-1 and the cold side of the evaporator EI1-3.

[0061] The constant pressure circulation subsystem consists of a constant pressure circulation heater EI3, a circulation pump PI1, and a one-way valve 1V1. The outlet of the one-way valve 1V1 is connected to the inlet of the circulation pump PI1, and the outlet of the circulation pump PI1 is connected to the inlet of the constant pressure circulation heater EI3.

[0062] The extraction fluid storage subsystem consists of an extraction fluid storage tank C1, a pressure pump P1, and a storage condenser E1. The outlet of the extraction fluid storage tank C1 is connected to the inlet of the storage condenser E1, and the outlet of the storage condenser E1 is connected to the inlet of the pressure pump P1.

[0063] The supply pipe 1L1 of the continuous extraction subsystem is connected to the outlet of the constant pressure circulation heater EI3 of the constant pressure circulation subsystem, the return pipe 1L2 is connected to the cold side inlet of the isopressure separation intermediate heat exchanger EI2 of the isopressure separation subsystem, the hot side outlet of the evaporator EI1-3 of the isopressure separation heat pump EI1 of the isopressure separation subsystem is connected to the inlet of the circulation pump PI1 of the constant pressure circulation subsystem, and the outlet of the pressure replenishing pump P1 of the extraction fluid storage subsystem is connected to the inlet of the one-way valve 1V1 of the constant pressure circulation subsystem.

[0064] The system features low investment, low operating costs, high continuity, and high safety and reliability.

[0065] The specific extraction and separation process of this system is as follows:

[0066] System parameters:

[0067] The system's maximum working pressure P, switching time t, and working temperature T are all adjustable; there are n (n≥3) extractors, with n-2 in working state P, 1 in standby state P, and 1 in 0-pressure standby state.

[0068] Prepare:

[0069] 1. Close all valves of the continuous extraction subsystem, open the upper quick-opening or feed gate of all extractors in the continuous extraction subsystem to fill with the extractant and close the upper quick-opening or feed gate; start the pressure booster pump P1 and the circulation pump PI1; open the supply valve 1 of all extractors to pressurize the corresponding extractor to ≤0.1MPa, and close all supply valve 1; open all venting and backpressure valves, and open the main venting valve VG1 to allow the air in all extractors to be discharged from the system through the venting and backpressure pipe L6 and the main venting valve VG1; repeat the above venting operation until the air in the system is completely removed, and close all valves of the continuous extraction subsystem.

[0070] 2. Open the supply valve 1-1V11 to the supply valve 1-(n-1)V1(n-1), pressurize the extractor 1Et1 to the extractor (n-1)Et(n-1) to pressure P, and close the supply valve 1-2V12 to the supply valve 1-(n-1)V1(n-1); open the return valve 1-1V21, the isobaric separation subsystem starts working, and the extractor 1Et1 enters the subcritical fluid extraction state; the pressure replenishment pump P1 automatically starts and stops according to whether the extractor in the continuous extraction subsystem maintains the working pressure P.

[0071] 3. After time t, open the supply valve 1-2V12 and the return valve 1-2V22. Extractor 2Et2 enters the subcritical fluid extraction state. After the next t, open the supply valve and return valve corresponding to the next extractor. Repeat this process until the supply valve 1-(n-2)V1(n-2) and the return valve 1-(n-2)V2(n-2) are opened. All extractors from extractor 1Et1 to extractor (n-2)Et(n-2) have entered the subcritical fluid extraction state.

[0072] run:

[0073] For a system with n (n≥3) extractors, the switching time is t, and i, j, k switch extractors cyclically according to the following table:

[0074] j n 1 … n-1 k n-1 n … n-2

[0075] Then, open the supply valve 1-k V1k and the return valve 1-k V2k, and extractor k Etk enters the extraction state. Close the supply valve 1-i V1i and the return valve 1-i V2i, and extractor i Eti completes extraction. Open the balancing and pressure-releasing valve i V5i and the balancing and pressure-releasing valve j V5j, and extractors Eti and Etj are balanced to 1 / 2P pressure through the balancing and pressure-releasing pipe L5. Close the balancing and pressure-releasing valve j V5j. Open the venting and backpressure valve j V6j, open the pressure-releasing valve V4, and start the pressure-releasing pump P2. The remaining 1 / 2P pressure extraction fluid in extractor Eti is backpressured to extractor Etj. Close the balancing and pressure-releasing valve i V5i and the venting and backpressure valve j V6j, and close the pressure-releasing pump P2 and the pressure-releasing valve V4. Open the lower quick-opening or discharge gate of extractor i Eti to remove the extraction residue, and close the lower quick-opening or discharge gate. Open extractor i Eti upper quick-opening or feed gate, load the extractant, close the upper quick-opening or feed gate;

[0076] Open the supply valve 1-i V1i to pressurize the extractor i Eti to ≤0.1MPa, then close the supply valve 1-i V1i; open the vent and backpressure valve i V6i, open the main vent valve VG1 to release the gas in the extractor i Eti, then close the vent and backpressure valve i V6i and the main vent valve VG1; repeat this step until the air in the extractor i Eti is emptied.

[0077] Example 2:

[0078] This embodiment discloses a supercritical fluid continuous extraction and depressurization separation system with self-balancing pressure boosting and depressurization and switching, operating on a single pressure stage with multiple extractors, such as... Figure 2 As shown, it consists of a continuous extraction subsystem, a supercritical fluid depressurization and separation subsystem, a supercritical fluid pressurization and circulation subsystem, and an extraction fluid storage subsystem.

[0079] The continuous extraction subsystem consists of extractor 1Et1, extractor 2Et2 to extractor nEtn, supply pipe 2L3, supply valve 2-1V31, supply valve 2-2V32 to supply valve 2-nV3n, return pipe 2L4, return valve 2-1V41, return valve 2-2V42 to return valve 2-nV4n, balancing and pressure-collecting pipe L5, balancing and pressure-collecting valve 1V51, balancing and pressure-collecting valve 2V52 to balancing and pressure-collecting valve nV5n, venting and backpressure pipe L6, venting and backpressure valve 1V61, venting and backpressure valve 2V62 to venting and backpressure valve nV6n, main venting valve VG1, pressure-collecting valve V4, return condenser E2, pressure-collecting pump P2, and check valve 3V3; the extraction fluid in supply pipe 2L3 and return pipe 2L4 is in a supercritical state.

[0080] Supply valves 2-1V31 and 2-2V32 are connected in parallel to the inlet of supply valve 2-n V3n and connected to supply pipe 2L3. One end of the balancing and pressure-reducing valves 1V51 and 2V52 is connected in parallel to the balancing and pressure-reducing valve n V5n and connected to the balancing and pressure-reducing pipe L5. The outlets of supply valves 2-1V31 and 2-2V32 and the other end of the balancing and pressure-reducing valves 1V51 and 2V52 are connected in parallel and then connected to the extraction fluid inlets of extractor 1Et1, extractor 2Et2 and extractor n Etn, respectively.

[0081] The reflux valves 2-1V41 and 2-2V42 to the inlet of reflux valve 2-n V4n and the vent and backpressure valves 1V61 and 2V62 to one end of the vent and backpressure valve n V6n are connected in parallel to the extraction fluid outlets of extractor 1Et1 and extractor 2Et2 to extractor n Etn, respectively. The reflux valves 2-1V41 and 2-2V42 to the outlet of reflux valve 2-n V4n are connected in parallel to the reflux pipe 2L4. The other end of the vent and backpressure valves 1V61 and 2V62 to the vent and backpressure valve n V6n is connected in parallel to the vent and backpressure pipe L6. The vent and backpressure pipe L6 is connected to the atmosphere through the main vent valve VG1.

[0082] The balancing and pressure-reducing pipe L5 is connected to the inlet of the pressure-reducing valve V4. The outlet of the pressure-reducing valve V4 is connected to the inlet of the return condenser E2. The outlet of the return condenser E2 is connected to the inlet of the pressure pump P2. The outlet of the pressure pump P2 is connected to the inlet of the check valve 3V3. The outlet of the check valve 3V3 is connected to the venting and backpressure pipe L6.

[0083] The pressure reduction separation subsystem is a supercritical fluid pressure reduction separation subsystem, which can be a single-stage or two-stage separation. In the single-stage separation, it consists of a pressure reduction separation intermediate heat exchanger ED2, a single-stage pressure regulating valve VD3, a single-stage pressure reduction separator SD1, a pressure reduction separation heat pump ED1, and a single-stage pressure reduction separation discharge valve VD1. The pressure reduction separation heat pump ED1 has a single-stage condenser ED1-1, an evaporator ED1-3, an expansion valve ED1-4, and a compressor ED1-5. In the two-stage separation, in addition to the components of the single-stage separation, there is also a two-stage pressure regulating valve VD4, a two-stage pressure reduction separator SD2, and a two-stage pressure reduction separation discharge valve VD2. The pressure reduction separation heat pump ED1 also has a two-stage condenser ED1-2.

[0084] During the first-stage separation, the outlet of the first-stage pressure regulating valve VD3 is connected to the cold-side inlet of the first-stage condenser ED1-1 of the pressure-reducing separation heat pump ED1; the cold-side outlet of the first-stage condenser ED1-1 is connected to the extraction fluid inlet of the first-stage pressure-reducing separator SD1; the extraction fluid outlet of the first-stage pressure-reducing separator SD1 is connected to the hot-side inlet of the intermediate heat exchanger ED2 of the pressure-reducing separation; the extract outlet of the first-stage pressure-reducing separator SD1 is connected to the first-stage pressure-reducing separation discharge valve VD1; the hot-side outlet of the intermediate heat exchanger ED2 of the pressure-reducing separation is connected to the hot-side inlet of the evaporator ED1-3 of the pressure-reducing separation heat pump ED1; the hot side of the first-stage condenser ED1-1 is connected to the cold side of the evaporator ED1-3; the cold side of the evaporator ED1-3 is connected to the compressor ED1-5; the compressor ED1-5 is reconnected to the hot side of the first-stage condenser ED1-1; and an expansion valve ED1-4 is installed between the hot side of the first-stage condenser ED1-1 and the cold side of the evaporator ED1-3.

[0085] During the secondary separation, based on the primary separation, the extractant fluid outlet of the primary pressure-reducing separator SD1 is connected to the inlet of the secondary pressure regulating valve VD4. The outlet of the secondary pressure regulating valve VD4 is connected to the cold-side inlet of the secondary condenser ED1-2 of the pressure-reducing heat pump ED1. The cold-side outlet of the secondary condenser ED1-2 is connected to the extractant fluid inlet of the secondary pressure-reducing separator SD2. The extractant fluid outlet of the secondary pressure-reducing separator SD2 is connected to the hot-side inlet of the intermediate heat exchanger ED2. The extract outlet of the secondary pressure-reducing separator SD2 is connected to the discharge outlet of the secondary pressure-reducing separator. Valve VD2 is connected, and the hot side outlet of the pressure-reducing separation intermediate heat exchanger ED2 is connected to the hot side inlet of the evaporator ED1-3 of the pressure-reducing separation heat pump ED1; the hot side of the first-stage condenser ED1-1 is connected to the cold side of the evaporator ED1-3, the cold side of the evaporator ED1-3 is connected to the compressor ED1-5, the compressor ED1-5 is connected to the hot side of the second-stage condenser ED1-2, the hot side of the second-stage condenser ED1-2 is connected to the hot side of the first-stage condenser ED1-1, and an expansion valve ED1-4 is installed between the hot side of the first-stage condenser ED1-1 and the cold side of the evaporator ED1-3.

[0086] The booster circulation subsystem is a supercritical fluid booster circulation subsystem, consisting of a one-way valve 2V2, a booster pump PD1, and a booster circulation heater ED3. The outlet of the one-way valve 2V2 is connected to the inlet of the booster pump PD1, the outlet of the booster pump PD1 is connected to the cold-side fluid inlet of the pressure-reducing separation intermediate heat exchanger ED2, and the cold-side fluid outlet of the pressure-reducing separation intermediate heat exchanger ED2 is connected to the inlet of the booster circulation heater ED3.

[0087] The extraction fluid storage subsystem consists of an extraction fluid storage tank C1, a pressure pump P1, and a storage condenser E1. The outlet of the extraction fluid storage tank C1 is connected to the inlet of the storage condenser E1, and the outlet of the storage condenser E1 is connected to the inlet of the pressure pump P1.

[0088] The supply pipe 2L3 of the continuous extraction subsystem is connected to the outlet of the booster circulation heater ED3 of the booster circulation subsystem, and the return pipe 2L4 is connected to the inlet of the first-stage pressure regulating valve VD3 of the depressurization separation subsystem; the hot-side outlet of the evaporator ED1-3 of the depressurization separation heat pump ED1 of the depressurization separation subsystem is connected to the inlet of the booster pump PD1 of the booster circulation subsystem, and the outlet of the supplementary pump P1 of the extraction fluid storage subsystem is connected to the inlet of the one-way valve 2V2 of the booster circulation subsystem.

[0089] The specific extraction and separation process of this system is as follows:

[0090] System parameters:

[0091] The system's maximum working pressure P, switching time t, and working temperature T are all adjustable; there are n (n≥3) extractors, with n-2 in working state P, 1 in standby state P, and 1 in 0-pressure standby state.

[0092] Prepare:

[0093] 1. Close all valves of the continuous extraction subsystem, open the upper quick-opening or feed gate of all extractors in the continuous extraction subsystem to fill with the extractant and close the upper quick-opening or feed gate; start the pressure replenishment pump P1 and the pressure boosting pump PD1; open the supply valve 2 of all extractors to pressurize the corresponding extractors to ≤0.1MPa, and close all supply valves 2; open all venting and backpressure valves, and open the main venting valve VG1 to allow the air in all extractors to be discharged from the system through the venting and backpressure pipe L6 and the main venting valve VG1; repeat the above venting operation until the air in the system is completely removed, and close all valves of the continuous extraction subsystem.

[0094] 2. Open the supply valve 2-1V31 to the supply valve 2-(n-1)V3(n-1), pressurize the extractor 1Et1 to the extractor n-1Et(n-1) to pressure P, and close the supply valve 2-2V32 to the supply valve 2-(n-1)V3(n-1); open the return valve 2-1V41, the pressure reduction separation subsystem starts working, and the extractor 1Et1 enters the supercritical fluid extraction state; the pressure replenishment pump P1 automatically starts and stops according to whether the extractor in the continuous extraction subsystem maintains the working pressure P.

[0095] 3. After time t, open the supply valve 2-2V32 and the return valve 2-2V42. Extractor 2Et2 enters the supercritical fluid extraction state. After the next t, open the supply valve and return valve corresponding to the next extractor. Repeat this process until the supply valve 2-(n-2)V3(n-2) and the return valve 2-(n-2)V4(n-2) are opened. All extractors from extractor 1Et1 to extractor (n-2)Et(n-2) have entered the supercritical fluid extraction state.

[0096] run:

[0097] Replace “supply valve 1-k V1k”, “return valve 1-k V2k”, “supply valve 1-i V1i”, and “return valve 1-i V2i” with “supply valve 2-k V3k”, “return valve 2-k V4k”, “supply valve 2-i V3i”, and “return valve 2-i V4i” respectively. The operating steps of this embodiment are the same as those of Embodiment 1.

[0098] Example 3:

[0099] This embodiment discloses a subcritical fluid continuous extraction and depressurization separation system with self-balancing pressure boosting and depressurization and switching between single pressure stage and multiple extractors, such as... Figure 3 As shown, it consists of a continuous extraction subsystem, a subcritical fluid depressurization and separation subsystem, a subcritical fluid pressurization and circulation subsystem, and an extraction fluid storage subsystem.

[0100] The continuous extraction subsystem consists of extractor 1Et1, extractor 2Et2 to extractor nEtn, supply pipe 1L1, supply valve 1-1V11, supply valve 1-2V12 to supply valve 1-nV1n, return pipe 1L2, return valve 1-1V21, return valve 1-2V22 to return valve 1-nV2n, balancing and pressure-collecting pipe L5, balancing and pressure-collecting valve 1V51, balancing and pressure-collecting valve 2V52 to balancing and pressure-collecting valve nV5n, venting and backpressure pipe L6, venting and backpressure valve 1V61, venting and backpressure valve 2V62 to venting and backpressure valve nV6n, main venting valve VG1, pressure-collecting valve V4, return condenser E2, pressure-collecting pump P2, and check valve 3V3. The extraction fluid in supply pipe 1L1 and return pipe 1L2 is in a subcritical state.

[0101] Supply valves 1-1V11 and 1-2V12 are connected in parallel to the inlet of supply valve 1-n V1n and connected to supply pipe 1L1. Balance and pressure relief valves 1V51 and 2V52 are connected in parallel to one end of balance and pressure relief valve n V5n and connected to balance and pressure relief pipe L5. Supply valves 1-1V11 and 1-2V12 are connected in parallel to the outlet of supply valve 1-n V1n and the other end of balance and pressure relief valves 1V51 and 2V52 are connected in parallel to the extraction fluid inlet of extractor 1Et1 and extractor 2Et2 to extractor n Etn, respectively.

[0102] The reflux valves 1-1V21 and 1-2V22 to the inlet of reflux valve 1-n V2n and the vent and backpressure valves 1V61 and 2V62 to one end of the vent and backpressure valve n V6n are connected in parallel to the extraction fluid outlets of extractor 1Et1 and extractor 2Et2 to extractor n Etn, respectively. The reflux valves 1-1V21 and 1-2V21 to the outlet of reflux valve 1-n V2n are connected in parallel to the reflux pipe 1L2. The other end of the vent and backpressure valves 1V61 and 2V62 to the vent and backpressure valve n V6n is connected in parallel to the vent and backpressure pipe L6. The vent and backpressure pipe L6 is connected to the atmosphere through the main vent valve VG1.

[0103] The balancing and pressure-reducing pipe L5 is connected to the inlet of the pressure-reducing valve V4. The outlet of the pressure-reducing valve V4 is connected to the inlet of the return condenser E2. The outlet of the return condenser E2 is connected to the inlet of the pressure pump P2. The outlet of the pressure pump P2 is connected to the inlet of the check valve 3V3. The outlet of the check valve 3V3 is connected to the venting and backpressure pipe L6.

[0104] The pressure reduction separation subsystem is a subcritical fluid pressure reduction separation subsystem, which can be a single-stage or two-stage separation. In the single-stage separation, it consists of a single-stage pressure regulating valve VD3, a pressure reduction separation intermediate heat exchanger ED2, a pressure reduction separation heat pump ED1, a single-stage pressure reduction separator SD1, and a single-stage pressure reduction separation unloading valve VD1. The pressure reduction separation heat pump ED1 has a single-stage condenser ED1-1, an evaporator ED1-3, an expansion valve ED1-4, and a compressor ED1-5. In the two-stage separation, in addition to the components of the single-stage separation, there is also a two-stage pressure regulating valve VD4, a two-stage pressure reduction separator SD2, and a two-stage pressure reduction separation unloading valve VD2. The pressure reduction separation heat pump ED1 also has a two-stage condenser ED1-2.

[0105] During the first-stage separation, the outlet of the first-stage pressure regulating valve VD3 is connected to the cold-side fluid inlet of the intermediate heat exchanger ED2 in the pressure-reducing separation. The cold-side fluid outlet of the intermediate heat exchanger ED2 is connected to the cold-side inlet of the first-stage condenser ED1-1 of the pressure-reducing separation heat pump ED1. The cold-side outlet of the first-stage condenser ED1-1 is connected to the extraction fluid inlet of the first-stage pressure-reducing separator SD1. The extraction fluid outlet of the first-stage pressure-reducing separator SD1 is connected to the hot-side fluid inlet of the intermediate heat exchanger ED2 in the pressure-reducing separation. The material outlet is connected to the first-stage pressure-reducing separation unloading valve VD1. The hot-side fluid outlet of the intermediate heat exchanger ED2 of the pressure-reducing separation is connected to the hot-side inlet of the evaporator ED1-3 of the pressure-reducing separation heat pump ED1. The hot side of the first-stage condenser ED1-1 is connected to the cold side of the evaporator ED1-3. The cold side of the evaporator ED1-3 is connected to the compressor ED1-5. The compressor ED1-5 is reconnected to the hot side of the first-stage condenser ED1-1. An expansion valve ED1-4 is installed between the hot side of the first-stage condenser ED1-1 and the cold side of the evaporator ED1-3.

[0106] During the secondary separation, based on the primary separation, the extractant fluid outlet of the primary pressure-reducing separator SD1 is connected to the inlet of the secondary pressure regulating valve VD4. The outlet of the secondary pressure regulating valve VD4 is connected to the cold-side inlet of the secondary condenser ED1-2 of the pressure-reducing heat pump ED1. The cold-side outlet of the secondary condenser ED1-2 is connected to the extractant fluid inlet of the secondary pressure-reducing separator SD2. The extractant fluid outlet of the secondary pressure-reducing separator SD2 is connected to the hot-side fluid inlet of the intermediate heat exchanger ED2. The extract outlet of the secondary pressure-reducing separator SD2 is connected to the discharge outlet of the secondary pressure-reducing separator. Valve VD2 is connected, and the hot-side fluid outlet of the pressure-reducing separation intermediate heat exchanger ED2 is connected to the hot-side inlet of the evaporator ED1-3 of the pressure-reducing separation heat pump ED1; the hot side of the first-stage condenser ED1-1 is connected to the cold side of the evaporator ED1-3, the cold side of the evaporator ED1-3 is connected to the compressor ED1-5, the compressor ED1-5 is connected to the hot side of the second-stage condenser ED1-2, the hot side of the second-stage condenser ED1-2 is connected to the hot side of the first-stage condenser ED1-1, and an expansion valve ED1-4 is installed between the hot side of the first-stage condenser ED1-1 and the cold side of the evaporator ED1-3.

[0107] The booster circulation subsystem is a subcritical fluid booster circulation subsystem, consisting of a one-way valve 2V2, a booster pump PD1, and a booster circulation heater ED3. The outlet of the one-way valve 2V2 is connected to the inlet of the booster pump PD1, and the outlet of the booster pump PD1 is connected to the inlet of the booster circulation heater ED3.

[0108] The extraction fluid storage subsystem consists of an extraction fluid storage tank C1, a pressure pump P1, and a storage condenser E1. The outlet of the extraction fluid storage tank C1 is connected to the inlet of the storage condenser E1, and the outlet of the storage condenser E1 is connected to the inlet of the pressure pump P1.

[0109] The supply pipe 1L1 of the continuous extraction subsystem is connected to the outlet of the booster circulation heater ED3 of the booster circulation subsystem, and the return pipe 1L2 is connected to the inlet of the first-stage pressure regulating valve VD3 of the depressurization separation subsystem. The hot-side outlet of the evaporator ED1-3 of the depressurization separation heat pump ED1 of the depressurization separation subsystem is connected to the inlet of the booster circulation pressurizing pump PD1 of the booster circulation subsystem. The outlet of the supplementary pressure pump P1 of the extraction fluid storage subsystem is connected to the inlet of the one-way valve 2V2 of the booster circulation subsystem.

[0110] The specific extraction and separation process of this system is as follows:

[0111] System parameters:

[0112] The system's maximum working pressure P, switching time t, and working temperature T are all adjustable; there are n (n≥3) extractors, with n-2 in working state P, 1 in standby state P, and 1 in 0-pressure standby state.

[0113] Prepare:

[0114] 1. Replace “supercritical fluid” and “supply valve 2” with “subcritical fluid” and “supply valve 1”. This step is the same as in Example 2.

[0115] 2. Replace the "isobaric separation subsystem" with the "pressure reduction separation subsystem". This step is the same as in Example 1.

[0116] 3. This step is the same as in Example 1.

[0117] run:

[0118] The operating steps in this embodiment are the same as those in Embodiment 1.

[0119] Example 4:

[0120] This embodiment discloses a combined system of subcritical fluid continuous extraction isobaric separation and subcritical fluid continuous extraction depressurization separation, which operates with a single pressure stage and multiple extractors, featuring pressure boosting and depressurization self-balancing and pump-back switching. Figure 4 As shown, it consists of a continuous extraction subsystem, an isobaric separation subsystem, a constant pressure circulation subsystem, a subcritical fluid depressurization separation subsystem, a subcritical fluid pressurization circulation subsystem, and an extraction fluid storage subsystem.

[0121] The continuous extraction subsystem comprises extractor 1Et1, extractor 2Et2 to extractor nEtn, supply pipe 1L1, supply valve 1-1V11, supply valve 1-2V12 to supply valve 1-nV1n, supply pipe 3L7, supply valve 3-1V71, supply valve 3-2V72 to supply valve 3-nV7n, reflux pipe 1L2, reflux valve 1-1V21, reflux valve 1-2V22 to reflux valve 1-nV2n, reflux pipe 3L8, reflux valve 3-1V81, reflux valve 3-2V82 to reflux valve 3-nV8n, balancing and pressure-relieving pipe L5, balancing and pressure-relieving valve 1V51, balancing and pressure-relieving valve 2V52 to balancing and pressure-relieving valve n The system consists of V5n, vent and backpressure pipe L6, vent and backpressure valve 1V61, vent and backpressure valve 2V62 to vent and backpressure valve n V6n, main vent valve VG1, pressure extraction valve V4, return condenser E2, pressure extraction pump P2, and check valve 3V3; the extractant fluid in supply pipe 1L1 and return pipe 1L2 is in a subcritical state, and the extractant fluid in supply pipe 3L7 and return pipe 3L8 is in a sub-subcritical state.

[0122] Supply valves 1-1V11 and 1-2V12 are connected in parallel to the inlet of supply valve 1-n V1n and then to supply pipe 1L1. Supply valves 3-1V71 and 3-2V72 are connected in parallel to the inlet of supply valve 3-n V7n and then to supply pipe 3L7. Balance and pressure-reducing valves 1V51 and 2V52 are connected in parallel to one end of balance and pressure-reducing valve n V5n and then to balance and pressure-reducing pipe L5. Supply valves 1-1V11 and 1-2V12 are connected in parallel to the outlet of supply valve 1-n V1n, supply valves 3-1V71 and 3-2V72 are connected in parallel to the outlet of supply valve 3-n V7n, and the other end of balance and pressure-reducing valves 1V51 and 2V52 are connected in parallel to the other end of balance and pressure-reducing valve n V5n and then to extractor 1Et1 and extractor 2Et2 and extractor n, respectively. Etn's extraction fluid inlet.

[0123] Reflux valves 1-1V21 and 1-2V22 to the inlet of reflux valve 1-n V2n, reflux valves 3-1V81 and 3-2V82 to the inlet of reflux valve 3-n V8n, and vent / backpressure valves 1V61 and 2V62 to one end of vent / backpressure valve n V6n are connected in parallel to the extraction fluid outlets of extractors 1Et1 and 2Et2 to extractor n Etn, respectively. Reflux valves 1-1V21 and 1-2V22 to the outlet of reflux valve 1-n V2n are connected in parallel to reflux pipe 1L2. Reflux valves 3-1V81 and 3-2V82 to the outlet of reflux valve 3-n V8n are connected in parallel to reflux pipe 3L8. Vent / backpressure valves 1V61 and 2V62 to vent / backpressure valve n are connected in parallel to the extraction fluid outlet of extractor n Etn. The other end of the valve port of V6n is connected in parallel to the vent and backpressure pipe L6, which is connected to the atmosphere through the main vent valve VG1.

[0124] The balancing and pressure-reducing pipe L5 is connected to the inlet of the pressure-reducing valve V4. The outlet of the pressure-reducing valve V4 is connected to the inlet of the return condenser E2. The outlet of the return condenser E2 is connected to the inlet of the pressure pump P2. The outlet of the pressure pump P2 is connected to the inlet of the check valve 3V3. The outlet of the check valve 3V3 is connected to the venting and backpressure pipe L6.

[0125] The isobaric separation subsystem and the constant pressure circulation subsystem are components and their connections are the same as in Example 1.

[0126] The subcritical fluid depressurization and separation subsystem and the subcritical fluid pressurization and circulation subsystem are the same components and their connections as in Example 3.

[0127] The continuous extraction subsystem's supply pipe 1L1 connects to the outlet of the constant pressure circulation heater EI3 of the constant pressure circulation subsystem, and the return pipe 1L2 connects to the cold side inlet of the isopressure separation intermediate heat exchanger EI2 of the isopressure separation subsystem. The hot side outlet of the evaporator EI1-3 of the isopressure separation heat pump EI1 of the isopressure separation subsystem connects to the inlet of the circulation pump PI1 of the constant pressure circulation subsystem. The supply pipe 3L7 connects to the outlet of the pressure boosting circulation heater ED3 of the pressure boosting circulation subsystem, and the return pipe 3L8 connects to the inlet of the first-stage pressure regulating valve VD3 of the pressure reducing separation subsystem. The cold side outlet of the evaporator ED1-3 of the pressure reducing separation heat pump ED1 of the pressure reducing separation subsystem connects to the inlet of the pressure boosting pump PD1 of the pressure boosting circulation subsystem. The outlet of the supplementary pressure pump P1 of the extraction fluid storage subsystem is connected in parallel to the inlets of the one-way valve 1V1 of the constant pressure circulation subsystem and the one-way valve 2V2 of the pressure boosting circulation subsystem.

[0128] The specific extraction and separation process of this system is as follows:

[0129] System parameters:

[0130] The system's maximum working pressure P, switching time t, and working temperature T are all adjustable; there are n (n≥4) extractors, with n-2 in working state, of which m (1≤m≤n-3) are in subcritical fluid extraction state, nm-2 are in sub-subcritical fluid extraction state, 1 is in P-pressure waiting state, and 1 is in 0-pressure waiting state.

[0131] Prepare:

[0132] 1. Close all valves of the continuous extraction subsystem, open the upper quick-opening or feed gate of all extractors in the continuous extraction subsystem, fill with the extractant, and close the upper quick-opening or feed gate; start the pressure replenishment pump P1, the circulation pump PI1 of the constant pressure circulation subsystem, and the pressure boosting pump PD1 of the subcritical fluid boosting circulation subsystem; open the supply valve 1 of all extractors, pressurize the corresponding extractors to ≤0.1MPa, and close all supply valve 1; open all venting and backpressure valves, and open the main venting valve VG1, so that the air in all extractors is discharged from the system through the venting and backpressure pipe L6 and the main venting valve VG1; repeat the above venting operation until the air in the system is completely purged, and close all valves of the continuous extraction subsystem.

[0133] 2. Open the supply valve 1-1V11 to the supply valve 1-(n-1)V1(n-1), pressurize the extractor 1Et1 to the extractor (n-1)Et(n-1) to pressure P, and close the subcritical fluid supply valve 1-2V12 to the supply valve 1-(n-1)V1(n-1); open the reflux valve 1-1V21, the isobaric separation subsystem starts working, and the extractor 1Et1 enters the subcritical fluid extraction state; the pressure pump P1 automatically starts and stops according to whether the extractor maintains the working pressure P according to the working state of the continuous extraction subsystem.

[0134] 3. After time t, open supply valve 1-2V12 and return valve 1-2V22, and extractor 2Et2 enters the subcritical fluid extraction state. After the next t, open the supply valve 1 and return valve 1 corresponding to the next extractor. Repeat this process until supply valve 1-(m+1)V1(m+1) and return valve 1-(m+1)V2(m+1) are opened, and extractor (m+1)Et(m+1) enters the subcritical fluid extraction state. Close supply valve 1-1V11 and return valve 1-1V21, and open supply valve 3-1V71 and return valve 3-1V81. The pressure reduction separation subsystem starts working, and extractor 1Et1 enters the sub-subcritical fluid extraction state. After t... Close the supply valve 1 and return valve 1 corresponding to the next extractor, open the supply valve 3 and return valve 3 corresponding to the extractor, repeat this process until the supply valve 1-(n-2)V1(n-2) and return valve 1-(n-2)V2(n-2) are opened, and the extractor (n-2)Et(n-2) enters the subcritical fluid extraction state. Close the supply valve 1-(nm-2)V1(nm-2) and return valve 1-(nm-2)V2(nm-2), open the supply valve 3-(nm-2)V7(nm-2) and return valve 3-(nm-2)V8(nm-2), and the extractor (nm-2)Et(nm-2) enters the sub-subcritical fluid extraction state.

[0135] run:

[0136] For a system with n (n≥4) extractors, with a switching time of t, extractors i, j, k, and l are switched cyclically according to the following table:

[0137] j n 1 … nm-1 … n-1 k n-1 n … nm-2 … n-2 l nm-1 nm … n … nm-2

[0138] Then, open the supply valve 1-k V1k and the return valve 1-k V2k, and extractor k Etk enters the subcritical fluid extraction state. Close the supply valve 1-l V1l and the return valve 1-l V2l, and open the supply valve 3-l V7l and the return valve 3-l V8l, and extractor l Etl enters the subcritical fluid extraction state. Close the supply valve 3-i V7i and the return valve 3-i V8i, and extractor i Eti completes extraction. Open the balancing and pressure-relieving valve i V5i and the balancing and pressure-relieving valve j V5j, and extractors Eti and Etj are balanced to 1 / 2P pressure through the balancing and pressure-relieving pipe L5. Close the balancing and pressure-relieving valve j V5j. Open the venting and backpressure valve j V6j, open the pressure-relieving valve V4, and start the pressure-relieving pump P2. The remaining 1 / 2P pressure extraction fluid in extractor Eti is backpressured to extractor Etj. Close the balancing and pressure-relieving valve i V6j. V5i and the venting and backpressure valve j V6j, close the suction pump P2 and suction valve 4V4; open the lower quick-opening or discharge gate of extractor i Eti to remove the residue, and close the lower quick-opening or discharge gate; open the upper quick-opening or feed gate of extractor i Eti to load the extractant, and close the upper quick-opening or feed gate.

[0139] Open the supply valve 1-i V1i to pressurize the extractor i Eti to ≤0.1MPa, then close the supply valve 1-i V1i; open the vent and backpressure valve i V6i, open the main vent valve VG1 to release the gas in the extractor i Eti, then close the vent and backpressure valve i V6i and the main vent valve VG1; repeat this step until the air in the extractor i Eti is emptied.

[0140] Example 5:

[0141] This embodiment discloses a combined subcritical fluid continuous extraction isobaric separation and supercritical fluid continuous extraction depressurization separation system with single-pressure-stage multi-extractor operation, featuring pressure boosting and depressurization self-balancing and pump-back switching. Figure 5 As shown, it consists of a continuous extraction subsystem, an isobaric separation subsystem, a constant pressure circulation subsystem, a supercritical fluid depressurization separation subsystem, a supercritical fluid pressurization circulation subsystem, and an extraction fluid storage subsystem.

[0142] The continuous extraction subsystem comprises extractor 1Et1, extractor 2Et2 to extractor nEtn, supply pipe 1L1, supply valve 1-1V11, supply valve 1-2V12 to supply valve 1-nV1n, supply pipe 2L3, supply valve 2-1V31, supply valve 2-2V32 to supply valve 2-nV3n, reflux pipe 1L2, reflux valve 1-1V21, reflux valve 1-2V22 to reflux valve 1-nV2n, reflux pipe 2L4, reflux valve 2-1V41, reflux valve 2-2V42 to reflux valve 2-nV4n, balancing and pressure-reducing pipe L5, balancing and pressure-reducing valve 1V51, balancing and pressure-reducing valve 2V52 to balancing and pressure-reducing valve n The system consists of V5n, vent and backpressure pipe L6, vent and backpressure valve 1V61, vent and backpressure valve 2V62 to vent and backpressure valve n V6n, main vent valve VG1, pressure extraction valve V4, return condenser E2, pressure extraction pump P2, and check valve 3V3; the extractant fluid in supply pipe 1L1 and return pipe 1L2 is in a subcritical state; the extractant fluid in supply pipe 2L3 and return pipe 2L4 is in a supercritical state.

[0143] Supply valves 1-1V11 and 1-2V12 are connected in parallel to the inlet of subcritical fluid supply valve 1-n V1n and connected to supply pipe 1L1. Supply valves 2-1V31 and 2-2V32 are connected in parallel to the inlet of supply valve 2-n V3n and connected to supply pipe 2L3. Balancing and pressure-reducing valves 1V51 and 2V52 are connected in parallel to one end of balancing and pressure-reducing valve n V5n and connected to balancing and pressure-reducing pipe L5. Supply valves 1-1V11 and 1-2V12 are connected to the outlet of supply valve 1-n V1n, supply valves 2-1V31 and 2-2V32 are connected to the outlet of supply valve 2-n V3n, and balancing and pressure-reducing valves 1V51 and 2V52 are connected to balancing and pressure-reducing valve n. The other end of the valve port of V5n is connected in parallel to the extraction fluid inlet of extractor 1Et1, extractor 2Et2 to extractor nEtn respectively.

[0144] Reflux valves 1-1V21 and 1-2V22 to the inlet of reflux valve 1-n V2n, reflux valves 2-1V41 and 2-2V42 to the inlet of reflux valve 2-n V4n, and vent / backpressure valves 1V61 and 2V62 to one end of vent / backpressure valve n V6n are connected in parallel and then connected to the extraction fluid outlets of extractor 1Et1, extractor 2Et2, and extractor nEtn, respectively. Reflux valves 1-1V21 and 1-2V22 to the outlet of reflux valve 1-n V2n are connected in parallel to reflux pipe 1L2. Reflux valves 2-1V41 and 2-2V42 to the outlet of reflux valve 2-n V4n are connected in parallel to reflux pipe 2L4. Vent / backpressure valves 1V61 and 2V62 to vent / backpressure valve n are connected in parallel to the outlet of vent / backpressure valve n. The other end of the valve port of V6n is connected in parallel to the vent and backpressure pipe L6, which is connected to the atmosphere through the main vent valve VG1.

[0145] The balancing and pressure-reducing pipe L5 is connected to the inlet of the pressure-reducing valve V4. The outlet of the pressure-reducing valve V4 is connected to the inlet of the return condenser E2. The outlet of the return condenser E2 is connected to the inlet of the pressure pump P2. The outlet of the pressure pump P2 is connected to the inlet of the check valve 3V3. The outlet of the check valve 3V3 is connected to the venting and backpressure pipe L6.

[0146] The isobaric separation subsystem and the constant pressure circulation subsystem are components and their connections are the same as in Example 1.

[0147] The supercritical fluid depressurization and separation subsystem and the supercritical fluid pressurization and circulation subsystem are the same components and their connections as in Example 2.

[0148] The continuous extraction subsystem's supply pipe 1L1 connects to the outlet of the constant pressure circulation heater EI3 of the constant pressure circulation subsystem, and the return pipe 1L2 connects to the cold side inlet of the isopressure separation intermediate heat exchanger EI2 of the isopressure separation subsystem. The hot side outlet of the evaporator EI1-3 of the isopressure separation heat pump EI1 of the isopressure separation subsystem connects to the inlet of the circulation pump PI1 of the constant pressure circulation subsystem. The supply pipe 2L3 connects to the outlet of the pressure boosting circulation heater ED3 of the pressure boosting circulation subsystem, and the return pipe 2L4 connects to the inlet of the first-stage pressure regulating valve VD3 of the pressure reducing separation subsystem. The hot side outlet of the evaporator ED1-3 of the pressure reducing separation heat pump ED1 of the pressure reducing separation subsystem connects to the inlet of the pressure boosting pump PD1 of the pressure boosting circulation subsystem. The outlet of the supplementary pressure pump P1 of the extraction fluid storage subsystem connects to the inlets of the one-way valve 1V1 of the constant pressure circulation subsystem and the one-way valve 2V2 of the pressure boosting circulation subsystem.

[0149] The specific extraction and separation process of this system is as follows:

[0150] System parameters:

[0151] The system's maximum working pressure P, switching time t, and working temperature T are all adjustable; there are n (n≥4) extractors, of which n-2 are in working state, m (1≤m≤n-3) are in subcritical fluid extraction state, nm-2 are in supercritical fluid extraction state, 1 is in P-pressure waiting state, and 1 is in 0-pressure waiting state.

[0152] Prepare:

[0153] 1. Replace the "subcritical fluid boosting circulation subsystem" in Example 4 with the "supercritical fluid boosting circulation subsystem". This step is the same as in Example 4.

[0154] 2. This step is the same as in Example 4;

[0155] 3. Replace “supply valve 3-1V71 and return valve 3-1V81” with “supply valve 2-1V31 and return valve 2-1V41” in Example 4, “supply valve 3 and return valve 3” with “supply valve 2 and return valve 2”, “supply valve 3-(nm-2)V7(nm-2) and return valve 3-(nm-2)V8(nm-2)” with “supply valve 2-(nm-2)V3(nm-2) and return valve 2-(nm-2)V4(nm-2)”, and “subcritical fluid extraction state” with “supercritical fluid extraction state”. This step is the same as in Example 4.

[0156] run:

[0157] Replace “supply valve 3-l V7l and return valve 3-l V8l” with “supply valve 2-l V3l and return valve 2-l V4l”, “subcritical fluid” with “supercritical fluid”, and “supply valve 3-i V7i and return valve 3-i V8i” with “supply valve 2-i V3i and return valve 2-i V4i”. The operating steps of this embodiment are the same as those of embodiment 4.

[0158] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A continuous extraction and separation system with pressure boosting, depressurization, self-balancing, and evacuation, characterized in that, It includes a continuous extraction subsystem, which is connected to an isobaric separation subsystem and / or a depressurization separation subsystem; the continuous extraction subsystem is connected to a constant pressure circulation subsystem and / or a pressurization circulation subsystem; and the constant pressure circulation subsystem and / or the pressurization circulation subsystem are connected to an extraction fluid storage subsystem, an isobaric separation subsystem and / or a depressurization separation subsystem. The continuous extraction subsystem includes multiple extractors connected in parallel. The extraction fluid inlet of the extractor is connected to the balance and pressure-suction pipe through a balance and pressure-suction valve, and the extraction fluid outlet of the extractor is connected to the vent and back pressure pipe through a vent and back pressure valve. The vent and back pressure pipe is connected to the atmosphere through a main vent valve. The balancing and pressure-extracting pipe is connected to the return condenser via a pressure-extracting valve. The return condenser is connected to the inlet of the pressure-extracting pump, and the outlet of the pressure-extracting pump is connected to the venting and backpressure pipe via a check valve. By opening the balancing and pressure-extracting valves of the finished extractor and the newly installed extractor, the extractant fluid from the finished extractor is balanced to the newly installed extractor. Then, by opening the balancing and pressure-extracting valves of the finished extractor and the venting and backpressure valves of the newly installed extractor, the pressure-extracting pump draws the remaining extractant fluid from the finished extractor into the newly installed extractor, thus switching the process.

2. The continuous extraction and separation system with pressure boosting, depressurization self-balancing, and extraction as described in claim 1, characterized in that, The extraction fluid inlet of the extractor is connected to the supply pipe via a supply valve; the extraction fluid outlet of the extractor is connected to the return pipe via a return valve; the isobaric separation subsystem and / or the depressurization separation subsystem are both connected to the continuous extraction subsystem via corresponding return pipes; the isobaric separation subsystem is connected to the constant pressure circulation subsystem; the depressurization separation subsystem is connected to the pressurization circulation subsystem; and the constant pressure circulation subsystem and / or the pressurization circulation subsystem are both connected to the continuous extraction subsystem via corresponding supply pipes.

3. The continuous extraction and separation system with pressure boosting, depressurization self-balancing, and extraction as described in claim 2, is characterized in that... The isobaric separation subsystem is a single-stage or multi-stage separation system, which includes an isobaric separation intermediate heat exchanger, an isobaric separator, and an isobaric separation heat pump connected in series. The isobaric separation heat pump includes a compressor, an expansion valve, an evaporator, and a condenser. The cold side of the condenser in the same stage is connected to the isobaric separator. The extract outlet of the isobaric separator is equipped with a discharge valve. The isobaric separation heat pump condenser and the number of isobaric separator stages are the same as the number of isobaric separation stages. The cold-side fluid inlet of the intermediate heat exchanger of the isobaric separation is connected to the return pipe. The cold-side fluid outlet of the intermediate heat exchanger of the isobaric separation is connected to the cold-side inlet of the first-stage condenser. The extraction fluid outlet of the last stage isobaric separator is connected to the hot-side fluid inlet of the intermediate heat exchanger of the isobaric separation. The hot-side fluid outlet of the intermediate heat exchanger of the isobaric separation is connected to the hot-side inlet of the heat pump evaporator. In an isobaric separation heat pump, the hot side of the condenser of adjacent stages is connected, the hot side of the first stage condenser is connected to the cold side of the evaporator, and an expansion valve is installed between the two. The cold side of the evaporator is connected to the compressor, and the compressor is connected to the hot side of the last stage condenser. The constant pressure circulation subsystem includes a constant pressure circulation heater, the outlet of which is connected to the supply pipe, the inlet of which is connected to the outlet of the circulation pump, the inlet of which is connected to the outlet of the one-way valve, and the inlet of the circulation pump is connected to the hot side outlet of the evaporator of the isobaric separation heat pump.

4. The continuous extraction and separation system with pressure boosting, depressurization, self-balancing, and extraction as described in claim 2, characterized in that, The pressure reduction separation subsystem is a supercritical fluid pressure reduction separation subsystem; the pressure reduction separation subsystem is a single-stage or multi-stage separation, which includes a pressure reduction separation intermediate heat exchanger, a pressure reduction separator, a pressure regulating valve and a pressure reduction separation heat pump connected in series. The pressure reduction separation heat pump includes a compressor, an expansion valve, an evaporator and a condenser. The pressure regulating valve, the cold side of the condenser and the pressure reduction separator of the same stage are connected in sequence. The extract outlet of the pressure reduction separator is equipped with a discharge valve. The pressure regulating valve, the pressure reducing separation heat pump condenser, and the pressure reducing separator have the same number of stages as the pressure reducing separation stage. The inlet of the first-stage pressure regulating valve is connected to the return pipe. The extraction fluid outlet of the last-stage pressure reducing separator is connected to the hot-side fluid inlet of the intermediate heat exchanger of the pressure reducing separation. The hot-side fluid outlet of the intermediate heat exchanger of the pressure reducing separation is connected to the hot-side inlet of the evaporator of the pressure reducing separation heat pump. In a step-down separation heat pump, the hot side of the adjacent condensers is connected, the hot side of the first-stage condenser is connected to the cold side of the evaporator, and an expansion valve is installed between the two. The cold side of the evaporator is connected to the compressor, and the hot side of the last-stage condenser is connected to the compressor. The pressurization circulation subsystem is a supercritical fluid pressurization circulation subsystem; the pressurization circulation subsystem includes a pressurization circulation heater, the outlet of which is connected to the supply pipe, the inlet of which is connected to the cold-side fluid outlet of the pressure-reducing separation intermediate heat exchanger, the cold-side fluid inlet of the pressure-reducing separation intermediate heat exchanger is connected to the outlet of the pressurization pump, the inlet of which is connected to the outlet of the one-way valve, and the inlet of which is connected to the hot-side outlet of the pressure-reducing separation heat pump evaporator.

5. The continuous extraction and separation system with pressure boosting, depressurization self-balancing, and extraction as described in claim 2, characterized in that, The pressure reduction separation subsystem is a subcritical fluid pressure reduction separation subsystem; the pressure reduction separation subsystem is a single-stage or multi-stage separation, which includes a pressure reduction separation intermediate heat exchanger, a pressure reduction separator, a pressure regulating valve and a pressure reduction separation heat pump connected in series. The pressure reduction separation heat pump includes a compressor, an expansion valve, an evaporator and a condenser. The pressure regulating valve, the cold side of the condenser and the pressure reduction separator of the same stage are connected in sequence. The extract outlet of the pressure reduction separator is equipped with a discharge valve. The pressure regulating valve, the pressure reducing separation heat pump condenser, and the pressure reducing separator have the same number of stages as the pressure reducing separation stage. The inlet of the first-stage pressure regulating valve is connected to the return pipe. The cold side of the pressure reducing separation intermediate heat exchanger is connected between the first-stage pressure regulating valve and the cold side of the first-stage condenser. The extraction fluid outlet of the last-stage pressure reducing separator is connected to the hot-side fluid inlet of the pressure reducing separation intermediate heat exchanger. The hot-side fluid outlet of the pressure reducing separation intermediate heat exchanger is connected to the hot-side inlet of the evaporator. In a step-down separation heat pump, the hot side of the adjacent condensers is connected, the hot side of the first-stage condenser is connected to the cold side of the evaporator, and an expansion valve is installed between the two. The cold side of the evaporator is connected to the compressor, and the hot side of the last-stage condenser is connected to the compressor. The pressurization circulation subsystem is a subcritical fluid pressurization circulation subsystem; the pressurization circulation subsystem includes a pressurization circulation heater, the outlet of which is connected to the supply pipe, the inlet of which is connected to the outlet of the pressurization circulation heater, the inlet of which is connected to the outlet of the pressurization pump, and the inlet of the pressurization pump is connected to the outlet of the one-way valve, and the inlet of the pressurization pump is connected to the hot side outlet of the evaporator of the pressure-reducing separation heat pump.

6. The continuous extraction and separation system with pressure boosting, depressurization, self-balancing, and extraction as described in claim 1, characterized in that, The extraction fluid storage subsystem includes an extraction fluid storage tank, the outlet of which is connected to the inlet of the storage condenser, the outlet of which is connected to the inlet of the pressure boosting pump, and the outlet of the pressure boosting pump is connected to the one-way valve inlet of the constant pressure circulation subsystem and / or the pressure boosting circulation subsystem.

7. The extraction and separation process of the continuous extraction and separation system with pressure boosting, depressurization self-balancing, and extraction as described in claim 3, is characterized in that... Includes the following steps: Subcritical fluid continuous extraction isobaric separation process: the extraction fluid is in a subcritical state; After the extractant fluid from the extraction fluid storage subsystem completes the condensation and pressurization process, it enters the constant pressure circulation subsystem circulation pump and flows through the constant pressure circulation heater. It then flows sequentially through the continuous extraction subsystem, the cold side of the isobaric separation intermediate heat exchanger, the isobaric separation subsystem, the hot side of the isobaric separation intermediate heat exchanger, and the hot side of the isobaric separation heat pump evaporator before returning to the constant pressure circulation subsystem circulation pump to complete the circulation operation. After extraction, the extractor switches the balancing and pressure-reducing valve, allowing the extractant fluid to be balanced through the balancing and pressure-reducing pipe to the newly installed extractor. Then, through the balancing and pressure-reducing valve, the balancing and pressure-reducing pipe, the pressure-reducing valve, the return condenser, the pressure pump, the check valve, the venting and back pressure pipe, and the venting and back pressure valve, all the remaining extractant fluid after balancing in the extractor is returned to the newly installed extractor. Then, the extractor is connected to the atmosphere, and the raffinate is discharged and the extractant is loaded. The extractor filled with extractant is filled with extractant fluid during the subsequent self-balancing switching process of the extractor pressure rise and fall, and the remaining extractant fluid after balancing in the subsequent extractor is drawn in by the pressure pump until the near-extraction pressure is reached. The extraction fluid storage subsystem replenishes the extraction fluid to each extractor via a circulation pump.

8. The extraction and separation process of the continuous extraction and separation system with pressure boosting, depressurization self-balancing, and extraction as described in claim 4, is characterized in that... Includes the following steps: Supercritical fluid continuous extraction and depressurization separation process: The extractant is in a supercritical state; after the extractant from the extractant storage subsystem completes the condensation and pressurization process, it enters the pressurization pump of the pressurization circulation subsystem and flows into the cold side of the depressurization separation intermediate heat exchanger. Then, it flows through the pressurization circulation heater, sequentially through the continuous extraction subsystem and the depressurization separation subsystem, and then into the hot side of the depressurization separation intermediate heat exchanger and the hot side of the depressurization separation heat pump evaporator before returning to the pressurization pump to complete the cycle operation. After extraction, the extractor switches the balancing and pressure-reducing valve, allowing the extractant fluid to be balanced through the balancing and pressure-reducing pipe to the newly installed extractor. Then, through the balancing and pressure-reducing valve, the balancing and pressure-reducing pipe, the pressure-reducing valve, the return condenser, the pressure pump, the check valve, the venting and back pressure pipe, and the venting and back pressure valve, all the remaining extractant fluid after balancing in the extractor is returned to the newly installed extractor. Then, the extractor is connected to the atmosphere, and the raffinate is discharged and the extractant is loaded. The extractor filled with extractant is filled with extractant fluid during the subsequent self-balancing switching process of the extractor pressure rise and fall, and the remaining extractant fluid after balancing in the subsequent extractor is drawn in by the pressure pump until the near-extraction pressure is reached. The extraction fluid storage subsystem replenishes the extraction fluid to each extractor via a circulation pump.

9. The extraction and separation process of the continuous extraction and separation system with pressure boosting, depressurization, self-balancing, and extraction as described in claim 5, is characterized in that... Includes the following steps: Subcritical fluid continuous extraction and depressurization separation process: The extractant fluid is in a subcritical state; after the extractant fluid from the extractant fluid storage subsystem completes the condensation and pressurization process, it enters the pressurization pump of the pressurization circulation subsystem and flows into the pressurization circulation heater. It then flows sequentially through the continuous extraction subsystem, the cold side of the depressurization separation intermediate heat exchanger, and the depressurization separation subsystem before flowing into the hot side of the depressurization separation intermediate heat exchanger and the hot side of the depressurization separation heat pump evaporator, before returning to the pressurization pump of the pressurization subsystem to complete the cycle operation. The extraction extractor switches a balancing and pressure-extraction valve, allowing the extractant fluid to be balanced through the balancing and pressure-extraction pipe to the newly installed extractant. Then, through the balancing and pressure-extraction valve, balancing and pressure-extraction pipe, pressure-extraction valve, condenser, pressure-extraction pump, check valve, venting and backpressure pipe, and venting and backpressure valve, all the remaining extractant fluid after balancing in the extraction extractor is returned to the newly installed extractant. Then, it is connected to the atmosphere and the extraction extractor is connected to complete the discharge of raffinate and loading of extractant. The extractor filled with extractant is filled with extractant fluid during the subsequent pressure rise and fall self-balancing switching process of the extraction extractor, and the remaining extractant fluid after balancing in the subsequent extraction extractor is drawn in by the pressure-extraction pump until the near-extraction pressure is reached. The extraction fluid storage subsystem replenishes the extraction fluid to each extractor via a circulation pump.

10. The extraction separation process of the continuous extraction separation system with self-balancing pressure boosting and depressurization plus extraction as described in any one of claims 7-9, characterized in that, Combining two or more subcritical fluid continuous extraction isobaric separation processes, subcritical fluid continuous extraction depressurization separation processes, or supercritical fluid continuous extraction depressurization separation processes yields parallel subcritical fluid continuous extraction isobaric separation combined processes with different extraction pressures, or parallel subcritical fluid continuous extraction depressurization separation combined processes, or parallel supercritical fluid continuous extraction depressurization separation combined processes; or yielding parallel subcritical fluid continuous extraction isobaric separation and subcritical fluid continuous extraction depressurization separation combined processes with the same or different extraction pressures, or parallel subcritical fluid continuous extraction isobaric separation and supercritical fluid continuous extraction depressurization separation combined processes, or parallel subcritical fluid continuous extraction isobaric separation and subcritical fluid continuous extraction depressurization separation and supercritical fluid continuous extraction depressurization separation combined processes.

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