A continuous processing method for extracting medicinal residues from traditional Chinese medicine

Abstract

This invention belongs to the field of medicinal residue treatment, specifically a continuous treatment method for medicinal residue from traditional Chinese medicine extraction. It employs a twin-screw extruder to pre-desolventize wet medicinal residue, removing a portion of the free solvent to obtain soluble residue. Next, the soluble residue is fed into a vacuum belt dryer, where it undergoes three-zone gradient drying under vacuum and nitrogen protection to obtain dry residue. Subsequently, ethanol is recovered from the desolvent using a heat pump solvent recovery tower and two-stage condensation. The ethanol obtained after dehydration using a TSA molecular sieve is reused in the extraction process. Simultaneously, explosion-proof safety management is achieved through multi-parameter interlocking control, and the wastewater achieves a high COD removal rate after UASB+A / O treatment. The dried residue is then ultra-finely pulverized and used as a dietary fiber additive. This method achieves continuous medicinal residue treatment, closed-loop solvent recovery, and resource utilization, offering advantages in energy saving, safety, and environmental protection, and is suitable for large-scale treatment of medicinal residue in the traditional Chinese medicine industry.

Description

Technical Field

[0001] This invention relates to the field of medicinal residue treatment, specifically a continuous treatment method for medicinal residue extracted from traditional Chinese medicine. Background Technology

[0002] During the extraction and production of traditional Chinese medicine, a large amount of wet residue containing ethanol and water is generated.

[0003] Traditional processing methods have many limitations: on the one hand, the residual ethanol solvent in the medicinal residue is difficult to recover efficiently, resulting in resource waste and posing flammable and explosive safety hazards; on the other hand, the drying process of the medicinal residue is energy-intensive and discontinuous, and the moisture content of the dried residue fluctuates greatly, affecting subsequent resource utilization; in addition, the wastewater and exhaust gas generated during the process, if not effectively treated, can easily cause environmental pollution and fail to meet environmental protection requirements. Furthermore, traditional equipment has low efficiency in desolvating the medicinal residue through extrusion, and its components are prone to wear and blockage, leading to high equipment maintenance costs and limited processing capacity. Therefore, a continuous processing method for medicinal residue from traditional Chinese medicine extraction is proposed to address these problems. Summary of the Invention

[0004] To address the problems of low solvent recovery efficiency, discontinuous processing, poor safety, failure to meet environmental standards, and low resource utilization rate of medicinal residues in existing technologies, this invention proposes a continuous treatment method for medicinal residues extracted from traditional Chinese medicine.

[0005] The technical solution adopted by this invention to solve its technical problem is: a continuous treatment method for medicinal residue extracted from traditional Chinese medicine, comprising the following steps:

[0006] S1. Screw Extrusion Pre-Desolventizing: Wet medicinal residue with a water content of 60%-80% and an ethanol content of 40%-70% is continuously fed into a twin-screw extruder. Through a screw diameter variable structure that gradually decreases from 200mm to 150mm, an extrusion pressure of 0.8-1.0MPa is achieved. Combined with a combination of forward and reverse screw elements and zoned temperature control (feed section at room temperature, compression section at 60℃, melting section at 70℃), more than 60% of the free solvent is removed, yielding medicinal residue with a water content of no more than 35% and a desolventized liquid containing ethanol.

[0007] S2. Vacuum zone drying: The soluble drug residue is fed into a vacuum belt dryer and, under a vacuum of -0.09MPa, passes through a high-temperature zone of 70±2℃, a medium-temperature zone of 55±2℃, and a low-temperature zone of 50±2℃ in sequence.

[0008] The residence time of the medicinal residue is controlled to be 20-40 minutes by adjusting the belt speed to 0.3-1.2 m / min, and then dried to a dry residue with a moisture content of no more than 5%.

[0009] Nitrogen gas is introduced throughout the drying process to maintain the residual oxygen content in the system at no more than 5%.

[0010] S3, Solvent closed-loop recovery: The ethanol-containing deionized liquid is sent to a heat pump solvent recovery tower with a tower temperature of 63±2℃ after being stabilized by a buffer tank.

[0011] The solvent is recovered by first-stage condensation using 60℃ hot water and second-stage condensation using circulating water.

[0012] The condensate is dehydrated by TSA temperature-switching adsorption molecular sieve to obtain ethanol with a purity of not less than 95%, which is then reused in the extraction process of traditional Chinese medicine.

[0013] S4. Safety and Environmental Control: Explosion-proof control is achieved through an ethanol concentration sensor with a trigger value of 0.8% LEL, oxygen content monitoring of no more than 5%, and tower pressure interlock of no more than 0.12 MPa. The generated wastewater is treated by a UASB anaerobic reactor and an A / O aerobic tank, with a chemical oxygen demand removal rate of no less than 85%.

[0014] S5. Resource utilization of dry residue: The dry medicinal residue is ultra-finely pulverized to a particle size distribution D90 of no more than 45μm to obtain a product that can be used as a dietary fiber additive.

[0015] Preferably, the threaded elements of the twin-screw extruder in S1 include a large-lead conveying element, a variable-density compression element, and a diamond-shaped block shearing element.

[0016] Among them, the lead of the large-lead conveying element is 80mm, the lead of the variable-density compression element gradually changes from 60mm to 30mm, and the shearing rate of the rhomboid block shearing element is 1500-2000s. -1 .

[0017] The compression section of the twin-screw extruder is equipped with anti-clogging drainage holes with a diameter of 3-5mm.

[0018] As a preferred embodiment, the surface of the twin screw in S1 is overlaid with a hard alloy wear-resistant layer with a hardness of not less than HRC55, and the bearing assembly adopts a heavy-duty thrust bearing with a pressure resistance greater than 1MPa.

[0019] Preferably, the high-temperature zone of the vacuum belt dryer in S2 is equipped with a steam coil or an electric heater.

[0020] The steam coil pressure is 0.3 MPa, and the electric heater power density is 8 W / cm². 2 The high-temperature zone is also equipped with an infrared moisture meter for real-time monitoring. The infrared moisture meter has a monitoring accuracy of ±0.5%. When the moisture content of the medicinal residue drops to 30%, the system automatically adjusts the belt speed to allow the medicinal residue to enter the medium-temperature zone.

[0021] A hot air auxiliary system with a wind speed of 0.5 m / s is added to the medium temperature zone.

[0022] The low-temperature zone is equipped with a cooling water circuit, and the outlet temperature of the cooling water circuit is no more than 40°C.

[0023] Preferably, the belt surface of the vacuum belt dryer in S2 is a composite structure of "Teflon coating + 304 stainless steel mesh belt", and the air permeability of the belt surface is 30%.

[0024] The thickness of the medicinal residue spread on the belt surface is controlled as follows: no more than 50 mm in the high-temperature zone, and no more than 30 mm in the medium- and low-temperature zones. The coefficient of variation of the moisture content of the dried medicinal residue is less than 5%.

[0025] As a preferred option, the heat pump system of the S3 heat pump solvent recovery tower recovers the latent heat of the 40-50℃ exhaust gas discharged from the vacuum belt dryer. After raising the temperature of the latent heat, it is added to the high-temperature zone of the vacuum belt dryer as a heat source, which can achieve an annual steam energy saving of 30%.

[0026] The 60°C hot water generated by the primary condenser is used to preheat the wet medicinal residue before screw extrusion through heat exchange pipes, preheating the wet medicinal residue to 40±2°C.

[0027] The secondary condenser uses circulating water as the condensing medium.

[0028] As a preferred option, the TSA molecular sieve dehydration in S3 adopts a "dynamic adsorption-regeneration" cycle mode.

[0029] The pressure during the adsorption stage is 0.3 MPa and the temperature is 25 °C.

[0030] The regeneration stage is achieved by purging with 120℃ hot air at a volume of 500m³. 3 / h, the regeneration cycle is 8h.

[0031] This cyclical mode ensures that the purity of ethanol after dehydration remains stable at 95%-98%.

[0032] Preferably, the explosion-proof control in S4 also includes: the solvent recovery tower is equipped with a dual pressure relief device, which includes a rupture disc with a pressure threshold of 0.15 MPa and a spring safety valve with a pressure threshold of 0.12 MPa.

[0033] The solvent recovery tower is also equipped with an emergency cooling system with a response time of less than 2 seconds and a cooling water flow rate of not less than 10 m³ / s. 3 / h.

[0034] The solvent recovery tower body is electrostatically grounded, with a grounding resistance of less than 4Ω.

[0035] Preferably, the inlet pressure of the nitrogen protection system in S2 is not less than 0.4 MPa.

[0036] Oxygen content monitoring points were set at the feed end, the middle section of the medium temperature zone, and the discharge end of the vacuum belt dryer, with a monitoring accuracy of ±0.3% for each point.

[0037] When any monitoring point detects an oxygen content greater than 5%, the system automatically increases the nitrogen injection rate to 25 m³ / h.

[0038] The system for realizing the continuous treatment of the residue from any Chinese herbal medicine extraction includes: a twin-screw extruder with an integrated frequency conversion control module, a zoned temperature control sleeve, and a vacuum dehydration component.

[0039] Vacuum belt dryer: integrates a three-zone heating system, nitrogen pipeline and online moisture meter.

[0040] Solvent recovery unit: includes a heat pump recovery tower, a two-stage condenser, and a TSA dehydration unit.

[0041] Safety control unit: includes ethanol concentration sensor, oxygen content sensor, safety PLC controller and nitrogen inerting system.

[0042] Wastewater treatment unit: includes UASB anaerobic reactor and A / O aerobic tank.

[0043] Resource recovery unit: an ultrafine pulverizing device.

[0044] The advantages of this invention are:

[0045] 1. This invention achieves continuous and efficient removal of more than 60% free solvent from wet medicinal residues through the screw diameter variation structure of the twin-screw extruder, the combination of forward / reverse thread elements, and the zoned temperature control design. It solves the problems of low and discontinuous solvent removal efficiency in traditional methods and improves the efficiency and continuity of solvent pre-removal.

[0046] 2. This invention achieves precise temperature-controlled drying of medicinal residues from a moisture content of ≤35% to ≤5% by using a three-zone temperature gradient and nitrogen protection system in a vacuum belt dryer. This solves the problems of high energy consumption and large fluctuations in moisture content in traditional drying methods, and improves the quality stability of the dried medicinal residues.

[0047] 3. This invention achieves efficient recovery and dehydration of ethanol solvent through a closed-loop design combining a heat pump solvent recovery tower with two-stage condensation and TSA temperature-switching adsorption molecular sieve, solving the problems of low solvent recovery rate and insufficient purity, and improving ethanol reuse rate and resource utilization rate.

[0048] 4. This invention achieves the resource utilization of medicinal residues by ultra-fine pulverizing dry medicinal residues to D90≤45μm, solves the problem of solid waste disposal of medicinal residues, and improves the economic value of medicinal residues.

[0049] 5. This invention achieves explosion-proof safety control of the treatment process through ethanol concentration sensor, oxygen content monitoring, tower pressure interlock and dual pressure relief device, solves the safety hazards in ethanol treatment process, improves production safety, and achieves high-COD wastewater purification function through UASB anaerobic reactor + A / O aerobic tank wastewater treatment system, solves the environmental pollution problem in the treatment process, and improves the environmental compliance rate. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a process flow diagram of the present invention;

[0052] Figure 2 This is a schematic diagram of the structure of the twin-screw extruder of the present invention;

[0053] Figure 3 This is a schematic diagram of the temperature zone of the vacuum belt dryer of the present invention;

[0054] Figure 4 This is a schematic diagram of the explosion-proof control system for the solvent recovery tower of the present invention. Detailed Implementation

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0057] This application discloses a continuous treatment method for the residue from traditional Chinese medicine extraction. (Refer to...) Figures 1 to 4 A continuous treatment method for the residue from traditional Chinese medicine extraction includes the following steps:

[0058] S1. Screw extrusion pre-desolventizing: Wet medicinal residue (containing 60-80% water and 40-70% ethanol) is continuously fed into a twin-screw extruder. Through the screw diameter changing structure (Φ200mm gradually changing to Φ150mm), an extrusion pressure of 0.8-1.0MPa is formed. With the combination of forward / reverse screw elements and zoned temperature control (normal temperature in the feeding section, 60℃ in the compression section, and 70℃ in the melting section), more than 60% of the free solvent is removed to obtain soluble medicinal residue (containing ≤35% water) and ethanol-containing desolventized liquid.

[0059] The twin-screw rotor has a hard alloy wear-resistant layer with an HRC ≥ 55 welded onto its surface, and the bearing assembly uses a heavy-duty thrust bearing (withstanding pressure > 1 MPa).

[0060] S2. Vacuum Zone Drying: The soluble drug residue enters a vacuum belt dryer and passes through a high-temperature zone (70±2℃), a medium-temperature zone (55±2℃), and a low-temperature zone (50±2℃) in sequence under a vacuum of -0.09MPa. The residence time is controlled by an adjustable belt speed of 0.3-1.2m / min for 20-40min, and the residue is dried to a moisture content of ≤5%. Nitrogen gas is introduced throughout the drying process to maintain a residual oxygen content of ≤5%.

[0061] The high-temperature zone of the vacuum belt dryer is equipped with a steam coil (pressure 0.3MPa) or an electric heater (power density 8W / cm³). 2 The system is equipped with an infrared moisture meter for real-time monitoring (accuracy ±0.5%). When the moisture content of the dregs drops to 30%, the belt speed is automatically adjusted to enter the medium-temperature zone. A hot air auxiliary system with a wind speed of 0.5 m / s is added to the medium-temperature zone, and a cooling water circuit is provided in the low-temperature zone (outlet temperature ≤40℃). The belt surface of the vacuum belt dryer is Teflon-coated + 304 stainless steel mesh belt (air permeability 30%). The material thickness is controlled as follows: ≤50mm in the high-temperature zone and ≤30mm in the medium-low temperature zone. The CV value (coefficient of variation) of the moisture content of the dried dregs is <5%. The inlet pressure of the nitrogen protection system is ≥0.4MPa. Oxygen content monitoring points (accuracy ±0.3%) are set at the feed end, the middle section of the medium-temperature zone, and the discharge end of the dryer. When the oxygen content at any monitoring point is >5%, the nitrogen injection rate is automatically increased to 25m³ / h. 3 / h.

[0062] S3. Solvent closed-loop recovery: The ethanol-containing deionized liquid enters the heat pump solvent recovery tower (tower temperature 63±2℃) after being stabilized in a buffer tank. The solvent is recovered by first-stage condensation (60℃ hot water) and second-stage condensation (circulating water). The condensate is dehydrated by TSA temperature-switching adsorption molecular sieve to obtain ethanol with a purity ≥95% for reuse in the extraction process.

[0063] The heat pump system of the heat pump solvent recovery tower recovers the latent heat (40-50℃) of the dryer exhaust gas, and after temperature increase, replenishes the heat source of the high-temperature zone, achieving an annual energy saving of 30% of steam. The 60℃ hot water generated by the primary condenser preheats the wet residue before screw extrusion (preheated to 40±2℃) through heat exchange pipelines. The secondary condenser uses circulating water. The TSA molecular sieve dehydration adopts a dynamic adsorption-regeneration cycle: the adsorption stage pressure is 0.3MPa and the temperature is 25℃, and the regeneration stage is purged with 120℃ hot air (air volume 500m³). 3 The regeneration cycle is 8 hours, ensuring that the ethanol purity remains stable at 95-98%.

[0064] S4. Safety and Environmental Control: Explosion-proof control is achieved through ethanol concentration sensor (0.8% LEL trigger), oxygen content monitoring (≤5%), and tower pressure interlock (≤0.12MPa). The generated wastewater is treated by UASB anaerobic reactor + A / O aerobic tank, with COD removal rate ≥85%.

[0065] Explosion-proof control also includes: the solvent recovery tower is equipped with a dual pressure relief device (0.15MPa rupture disc + 0.12MPa spring safety valve), and the emergency cooling system has a response time of <2s (cooling water flow rate ≥10m³ / h). 3 / h), and the electrostatic grounding resistance of the tower body is <4Ω.

[0066] S5. Resource utilization of dried residue: The dried medicinal residue is ultra-finely pulverized to D90≤45μm and used as a dietary fiber additive.

[0067] Preferably, the screw elements of the twin-screw extruder in S1 include a large-lead conveying element (lead 80mm), a variable-density compression element (lead 60mm→30mm), and a diamond-shaped block shearing element (shearing rate 1500-2000s). -1 The compression section has a 3-5mm anti-clogging drain hole.

[0068] A system for the continuous treatment of extraction residue from any traditional Chinese medicine includes:

[0069] Pre-treatment unit: twin-screw extruder (including variable frequency motor, grading temperature control sleeve, and vacuum dehydration assembly).

[0070] Drying unit: Vacuum belt dryer (including a three-zone heating system, nitrogen protection pipeline, and online moisture meter).

[0071] Solvent recovery unit: heat pump recovery tower, two-stage condenser, TSA molecular sieve dehydration device.

[0072] Safety control unit: ethanol concentration sensor, oxygen content analyzer, safety PLC (SIL2 level), nitrogen inerting system, pressure relief and cooling components.

[0073] Environmental protection units: UASB reactor, A / O aerobic tank.

[0074] Resource recovery unit: Ultrafine pulverization equipment (inert gas protection).

[0075] Taking the residue from the tanshinone ethanol extraction (containing 65% ethanol and 20% water) as an example, the specific steps are as follows:

[0076] Screw extrusion pre-desolventizing: Set the extrusion pressure to 0.8 MPa, the feeding section to room temperature, the compression section to 60°C, the melting section to 70°C, and the discharge hole to a vacuum of -0.06 MPa. Remove 58% ethanol to obtain soluble residue (containing 32% water).

[0077] Vacuum belt drying: vacuum degree -0.09MPa, belt speed 0.8m / min, residence time 35min; high temperature zone 70℃, medium temperature zone 55℃, low temperature zone 50℃, nitrogen residual oxygen content 4%, and the moisture content of the dried residue is 4.7%.

[0078] Solvent recovery: The recovery tower temperature is 63℃. The wet residue is preheated to 40℃ by primary condensing hot water. After secondary condensation, the VOC emission concentration is 18mg / m³. 3 The ethanol purity after dehydration using TSA molecular sieves is 96.5%.

[0079] Safety and environmental protection: The ethanol concentration throughout the process is <0.8% LEL, and the oxygen content is 4.2%; the COD value of the wastewater after UASB+A / O treatment is 95mg / L.

[0080] Resource utilization: The dry residue was pulverized to D90 = 42μm, and the retention rate of salvianolic acid B was 89.3% (HPLC detection), which meets the standards for dietary fiber additives.

[0081] I. Process Flow Diagram (including material flow and energy flow)

[0082] (1) Overall layout: A horizontally flowing continuous processing system, consisting of four main units from left to right: pretreatment, drying, recovery, and resource utilization.

[0083] (2) Material flow (solid arrow): wet medicine residue inlet → twin screw extruder → soluble medicine residue → vacuum belt dryer → dry medicine residue → ultrafine pulverizer → dietary fiber product; extrusion removal liquid → buffer tank → heat pump recovery tower → TSA molecular sieve → 95% ethanol (reuse).

[0084] (3) Energy flow (dashed arrow): Dryer exhaust (40-50℃) → heat pump heating → heat source of recovery tower; primary condensate hot water (60℃) → preheating of wet dregs (40±2℃).

[0085] (4) Safe and environmentally friendly flow: VOCs recovery tower → secondary condensation → emission meeting standards (<20mg / m³) 3Wastewater → UASB + A / O treatment → COD ≤ 100 mg / L.

[0086] II. Structure Layout Diagram of a Twin-Screw Extruder

[0087] (1) The screw has a variable diameter structure from the feed end (left) to the discharge end (right).

[0088] (2) Structural annotation:

[0089] Feeding section: Φ200mm diameter, large lead conveyor element (80mm lead, blue);

[0090] Compression section: Diameter Φ180mm, variable density compression element (lead 60mm→30mm gradually changes, orange), 3-5mm drain hole on the side wall (connected to vacuum pump);

[0091] Melting section: Φ150mm in diameter, diamond-shaped shear elements (red, marked with shear rate 1500-2000s). -1 ).

[0092] (3) Auxiliary annotations:

[0093] Wear-resistant layer: Hard alloy is welded onto the screw surface (partial enlarged view, marked HRC≥55);

[0094] Vacuum interface: Arrow points to drain hole (marked "-0.06MPa");

[0095] Temperature control sleeve: zone markings (feed section: ambient temperature; compression section: 60℃; melting section: 70℃).

[0096] III. Temperature Segmentation Diagram of Vacuum Belt Dryer

[0097] (1) Display the direction of the conveyor belt movement (left → right) and the layout of the three temperature zones.

[0098] (2) Partition labeling:

[0099] High-temperature zone: 40% of the length, steam coil / electric heater icon, material thickness ≤50mm, temperature 70±2℃.

[0100] Medium temperature zone: Length accounts for 30%, hot air circulation icon (wind speed 0.5m / s), material thickness ≤30mm, temperature 55±2℃.

[0101] Low temperature zone: 30% of the length, cooling water pipeline icon, outlet temperature ≤40℃, temperature 50±2℃.

[0102] (3) Common components:

[0103] Mesh belt: Teflon coating + 304 stainless steel (air permeability 30%).

[0104] Nitrogen gas line: runs through three zones and connects to three oxygen analyzers (monitoring points P1-P3).

[0105] IV. Schematic diagram of the explosion-proof control system for the solvent recovery tower

[0106] (1) Layered structure diagram: from top to bottom, it is divided into monitoring layer, tower body layer and emergency layer.

[0107] (2) Core Components:

[0108] Monitoring layer: Ethanol concentration sensor (marked "≥0.8% LEL trigger"), temperature sensor (marked ">70℃ trigger"), pressure sensor (marked ">0.12MPa trigger").

[0109] Tower body layers:

[0110] Heat pump icon (recovers 40-50℃ exhaust gas from dryer), two-stage condenser (stage 1: 60℃ hot water; stage 2: circulating water).

[0111] Emergency layer: Nitrogen inerting valve (response time 0.3s, labeled "residual oxygen ≤5%)", rupture disc (0.15MPa) + safety valve (0.12MPa), emergency cooling water (flow rate ≥10m³ / h). 3 / h, the pipe arrow points to the tower body)

[0112] (3) Interlocking logic: Sensor → SIL2 safety PLC → Actuator (nitrogen valve / cooling water valve), static grounding mark (marked "resistance < 4Ω").

[0113] Working Principle: Through the continuous and coordinated operation of five core units—pretreatment, drying, solvent recovery, safety and environmental protection control, and resource utilization—the system achieves efficient solvent recovery, waste volume reduction, and resource reuse from traditional Chinese medicine extraction residues. Its core principles include:

[0114] Continuous desolventizing and drying: Free solvent is pre-removed by twin-screw extrusion, combined with vacuum partition drying to reduce the moisture gradient of the residue and reduce subsequent energy consumption.

[0115] Closed-loop solvent recovery: Solvents are recovered using heat pump energy-saving technology, combined with temperature-switching adsorption dehydration, to achieve ethanol recycling.

[0116] Safety and environmental protection integration: Explosion-proof control is achieved through multi-parameter monitoring (ethanol concentration, oxygen content, pressure), and the supporting wastewater treatment system ensures that the wastewater is discharged in compliance with standards.

[0117] Energy cascade utilization: recover the latent heat of drying exhaust and waste heat from condensation to reduce overall energy consumption.

[0118] Resource utilization and added value: The dried medicinal residue is ultra-finely pulverized and used as a dietary fiber additive, realizing the resource utilization of solid waste.

[0119] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A continuous treatment method for the residue from traditional Chinese medicine extraction, characterized in that, Includes the following steps: S1. Screw extrusion pre-desolventizing: Wet medicinal residue with a water content of 60%-80% and an ethanol content of 40%-70% is continuously fed into a twin-screw extruder. Through the screw diameter variable structure that gradually changes from 200mm to 150mm, an extrusion pressure of 0.8-1.0MPa is formed. With the combination of forward and reverse screw elements and zoned temperature control, the feeding section is at room temperature, the compression section is at 60℃, and the melting section is at 70℃. More than 60% of the free solvent is removed to obtain medicinal residue with a water content of no more than 35% and ethanol-containing desolventized liquid. S2. Vacuum zone drying: The soluble drug residue is fed into a vacuum belt dryer and passes through a high temperature zone, a medium temperature zone, and a low temperature zone in sequence under a vacuum of -0.09MPa. The temperature in the high-temperature zone is 70±2℃, the temperature in the medium-temperature zone is 55±2℃, and the temperature in the low-temperature zone is 50±2℃. The residence time of the medicinal residue is controlled to be 20-40 minutes by an adjustable belt speed of 0.3-1.2 m / min, and the residue is dried to a moisture content of no more than 5%. Nitrogen gas is introduced throughout the drying process to maintain the residual oxygen level in the system at no more than 5%. S3, Solvent closed-loop recovery: The ethanol-containing descaling liquid is sent to a heat pump solvent recovery tower with a tower temperature of 63±2℃ after being stabilized in a buffer tank. The solvent is recovered by first-stage condensation using 60℃ hot water and second-stage condensation using circulating water. The condensate is dehydrated by TSA temperature-switching adsorption molecular sieve to obtain ethanol with a purity of not less than 95%, which is then reused in the extraction process of traditional Chinese medicine. S4. Safety and Environmental Control: Explosion-proof control is achieved through ethanol concentration sensors, oxygen content monitoring, and tower pressure interlocking. The trigger value for the ethanol concentration sensor is 0.8% LEL, the oxygen content monitoring is set to no more than 5%, and the tower pressure interlock value is set to no more than 0.12 MPa. The generated wastewater is treated by a UASB anaerobic reactor and an A / O aerobic tank, with a chemical oxygen demand removal rate of no less than 85%. S5. Resource utilization of dry residue: The dry medicinal residue is ultra-finely pulverized to a particle size distribution D90 of no more than 45μm to obtain a product that can be used as a dietary fiber additive.

2. The continuous treatment method for medicinal residue from traditional Chinese medicine extraction according to claim 1, characterized in that: The threaded components of the twin-screw extruder in S1 include a large-lead conveying component, a variable-density compression component, and a diamond-shaped block shearing component. Among them, the lead of the large-lead conveying element is 80mm, the lead of the variable-density compression element gradually changes from 60mm to 30mm, and the shearing rate of the rhomboid block shearing element is 1500-2000s. -1 ; The compression section of the twin-screw extruder is equipped with anti-clogging drainage holes with a diameter of 3-5mm.

3. The continuous treatment method for medicinal residue from traditional Chinese medicine extraction according to claim 1, characterized in that: The S1 twin screw has a hard alloy wear-resistant layer with a hardness of not less than HRC55 welded to its surface, and the bearing assembly adopts a heavy-duty thrust bearing with a pressure resistance greater than 1MPa.

4. The continuous treatment method for medicinal residue from traditional Chinese medicine extraction according to claim 1, characterized in that: The high-temperature zone of the vacuum belt dryer in S2 is equipped with a steam coil or an electric heater. The steam coil pressure is 0.3 MPa, and the electric heater power density is 8 W / cm². 2 ; The high-temperature zone is also equipped with an infrared moisture meter for real-time monitoring. The infrared moisture meter has a monitoring accuracy of ±0.5%. When the moisture content of the medicinal residue drops to 30%, the system automatically adjusts the belt speed to allow the medicinal residue to enter the medium-temperature zone. A hot air auxiliary system with a wind speed of 0.5 m / s is added to the medium temperature zone; The low-temperature zone is equipped with a cooling water circuit, and the outlet temperature of the cooling water circuit is no more than 40°C.

5. A continuous treatment method for medicinal residue from traditional Chinese medicine extraction according to claim 1, characterized in that: The belt surface of the vacuum belt dryer in S2 is a composite structure of "Teflon coating + 304 stainless steel mesh belt", and the air permeability of the belt surface is 30%. The thickness of the medicinal residue on the surface of the belt should be controlled as follows: no more than 50 mm in the high temperature zone, and no more than 30 mm in the medium and low temperature zones. The coefficient of variation of the moisture content of the dried medicinal residue is less than 5%.

6. A continuous treatment method for medicinal residue from traditional Chinese medicine extraction according to claim 1, characterized in that: The heat pump system of the S3 heat pump solvent recovery tower recovers the latent heat of the 40-50℃ exhaust gas from the vacuum belt dryer. After raising the temperature of the latent heat, it is added to the high-temperature zone of the vacuum belt dryer as a heat source, which can achieve an annual steam energy saving of 30%. The 60℃ hot water generated by the primary condenser is used to preheat the wet dregs before screw extrusion through the heat exchange pipeline, preheating the wet dregs to 40±2℃. The secondary condenser uses circulating water as the condensing medium.

7. A continuous treatment method for medicinal residue from traditional Chinese medicine extraction according to claim 1, characterized in that: The TSA molecular sieve dehydration in S3 adopts a "dynamic adsorption-regeneration" cycle mode; The pressure during the adsorption stage is 0.3 MPa and the temperature is 25 °C. The regeneration stage is achieved by purging with 120℃ hot air at a volume of 500m³. 3 / h, regeneration cycle 8h; This cyclical mode ensures that the purity of ethanol after dehydration remains stable at 95%-98%.

8. A continuous treatment method for medicinal residue from traditional Chinese medicine extraction according to claim 1, characterized in that: The explosion-proof control in S4 also includes: the solvent recovery tower is equipped with a dual pressure relief device, which includes a rupture disc with a pressure threshold of 0.15 MPa and a spring safety valve with a pressure threshold of 0.12 MPa; The solvent recovery tower is also equipped with an emergency cooling system with a response time of less than 2 seconds and a cooling water flow rate of not less than 10 m³ / s. 3 / h; The solvent recovery tower body is electrostatically grounded, with a grounding resistance of less than 4Ω.

9. A continuous treatment method for medicinal residue from traditional Chinese medicine extraction according to claim 1, characterized in that: The inlet pressure of the nitrogen protection system in S2 shall not be less than 0.4 MPa; Oxygen content monitoring points were set at the feed end, the middle section of the medium temperature zone, and the discharge end of the vacuum belt dryer, with a monitoring accuracy of ±0.3% for each point. When any monitoring point detects an oxygen content greater than 5%, the system automatically increases the nitrogen injection rate to 25m³. 3 / h.

10. A system for implementing a continuous treatment method for the residue from traditional Chinese medicine extraction as described in any one of claims 1-9, characterized in that, include: Twin-screw extruder: integrates frequency conversion control module, zoned temperature control sleeve and vacuum dehydration assembly; Vacuum belt dryer: integrates a three-zone heating system, nitrogen pipeline and online moisture meter; Solvent recovery unit: includes a heat pump recovery tower, a two-stage condenser, and a TSA dehydration unit; Safety control unit: includes ethanol concentration sensor, oxygen content sensor, safety PLC controller and nitrogen inerting system; Wastewater treatment unit: includes UASB anaerobic reactor and A / O aerobic tank; Resource recovery unit: an ultrafine pulverizing device.

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