Micro-negative pressure rotary evaporation and extraction combined continuous separation method

Abstract

The invention belongs to the technical field of chemical separation, and particularly relates to a micro-negative pressure rotary evaporation and extraction combined continuous separation method which comprises the following steps: (1) continuously extracting a material to be separated and an extracting solvent, and separating an extracting phase and a raffinate phase; an air pressure channel for connecting the extraction phase with the external atmosphere is arranged in the micro negative pressure channel; (2) enabling the extraction phase to enter a rotary evaporator through a pressure difference formed by the rotary evaporation bottle and the extraction tower for continuous rotary evaporation, and condensing, outputting and recovering the solvent; a one-way channel for enabling a recovered solvent to enter the rotary evaporation collecting bottle is arranged in the rotary evaporation instrument, a micro negative pressure channel for enabling an extraction phase to enter the rotary evaporation bottle is arranged between the rotary evaporation instrument and the extraction tower, and a loop channel for enabling the recovered solvent in the rotary evaporation collecting bottle to enter the extraction tower is also arranged between the rotary evaporation instrument and the extraction tower; and a supplementing channel for enabling volatile components discharged by the vacuum pump to enter the rotary evaporation collecting bottle is arranged between the rotary evaporation instrument and the vacuum pump. Through continuous micro-negative pressure rotary evaporation-extraction combination, the material separation efficiency is improved, the cost is reduced, and the method is healthy and environmentally friendly.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical separation, and in particular relates to a method for continuous separation by micro-negative pressure rotary evaporation extraction. Background Art

[0002] Material separation is an important chemical process that requires corresponding equipment and more energy investment. The separation technology based on the difference in boiling points of different liquids mainly includes processes such as distillation or rectification, and the separation technology based on the difference in polarity between oil and water phases mainly includes extraction process. The equipment of the distillation process is simple, but it cannot achieve the continuity of material input and output. Distillation can achieve the continuity of material input and output, but it requires higher equipment investment. Generally, material separation requires multiple steps, but the separation methods of different steps often lack synergy and linkage, resulting in low overall efficiency of material separation, which consumes a lot of manpower and energy costs, and causes certain safety and health risks. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for continuous separation by micro-negative pressure rotary evaporation extraction, so as to improve the material separation efficiency in the process of biomass hydrothermal liquefaction reaction, reduce costs and meet the requirements of health and environmental protection.

[0004] To achieve the above object, the technical solution adopted by the present invention is as follows: A method for continuous separation by micro-negative pressure rotary evaporation extraction, comprising the following steps: Step (1), the material to be separated and the extraction solvent enter the extraction tower from the material inlet and the solvent inlet respectively through the liquid level difference or the pressure difference formed by the centrifugal pump for continuous extraction, and the extraction phase (solution to be rotary evaporated) and the raffinate phase (material after extraction) are continuously separated and output, and then discharged from the extraction tower through the extraction phase outlet and the raffinate phase outlet respectively; Step (2), the extraction phase enters the rotary evaporator through the pressure difference formed between the rotary evaporator and the extraction tower, performs continuous rotary evaporation, and continuously condenses and outputs the recovered solvent; The rotary evaporator is provided with a one-way channel for allowing the recovered solvent to enter the rotary evaporation collection bottle, and can be used to maintain a slight negative pressure system in the rotary evaporation bottle, and the condensed recovered solvent is continuously output to the rotary evaporation collection bottle through the pressure difference formed by the liquid level of the recovered solvent above the one-way channel; A micro-negative pressure channel is provided between the rotary evaporator and the extraction tower to allow the extraction phase to enter the rotary evaporation bottle. The micro-negative pressure channel is connected to the outside atmosphere and is used to stabilize the stratification position between the extraction phase and the raffinate phase in the extraction tower, thereby ensuring the stability of the extraction process. The pressure difference between the extraction phase output by the extraction tower and the rotary evaporation bottle is maintained through the micro-negative pressure channel, thereby realizing the delivery of the extraction solvent to the rotary evaporation bottle through the pressure difference, and then recovering the volatile components of the extraction phase into the rotary evaporation bottle; A loop channel is provided between the rotary evaporator and the extraction tower for allowing the recovered solvent in the rotary evaporation collection bottle to enter the solvent inlet of the extraction tower; a supplementary channel is provided between the rotary evaporator and the vacuum pump for allowing the volatile components discharged by the vacuum pump to enter the rotary evaporation collection bottle.

[0005] In a preferred example, in step (2), the water bath heating temperature set in the water bath pot connected to the rotary evaporator is 10°C to 50°C higher than the boiling point of the extraction solvent at a slight negative pressure relative vacuum degree ≤0.1 MPa, and the cooling temperature set in the circulating cooler connected to the rotary evaporator is 10°C to 50°C lower than the boiling point of the extraction solvent at a slight negative pressure relative vacuum degree ≤0.1 MPa.

[0006] In a preferred example, in step (2), the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel is maintained at ≤0.1 MPa.

[0007] In a preferred example, in step (2), the relative vacuum degree of the slight negative pressure in the loop channel is maintained to be ≤ the relative vacuum degree of the slight negative pressure in the slight negative pressure channel.

[0008] In a preferred example, in step (2), a closed space for storing and releasing volatile components is provided in the vacuum pump, and by maintaining the relative vacuum degree of the micro-negative pressure in the replenishing channel ≤ the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel, the pressure difference of the micro-negative pressure allows the volatile components in the closed space to be recovered into the rotary evaporation collection bottle.

[0009] Compared with the prior art, the advantages and positive effects of the present invention are as follows: 1. Improve efficiency: The continuous micro-negative pressure rotary evaporation-extraction combination improves the efficiency of material separation; it is mainly reflected in two aspects: first, all kinds of substances are continuously transported by pipelines, and the efficiency of automated separation operation is greater than that of manual operation; second, the efficiency of rotary evaporation under micro-negative pressure atmosphere is higher than that of atmospheric distillation or rectification; 2. Reduce costs: The continuous micro-negative pressure rotary evaporation-extraction combination reduces the cost of material separation; it is mainly reflected in two aspects: first, the micro-negative pressure design realizes the ingenious combination of the extraction tower and the rotary evaporator, reducing the cost of the rotary evaporator vacuum pump operation and the pumping of various liquids; second, the micro-negative pressure system is used to recover the solvent discharged from the rotary evaporator and the vacuum pump and the volatile components in the extraction tower into the rotary evaporation collection bottle, and the solvent in the rotary evaporation collection bottle is continuously recovered by the liquid level difference or the centrifugal pump to the extraction tower for extraction operation, thereby reducing the overall consumption of solvents.

[0010] 3. Healthy and environmentally friendly: The entire continuous micro-negative pressure system reduces the emission of volatile components, thereby reducing harm to human health and pollution to the environment.

[0011] The present invention adopts a simple channel structure to make the material separation in the biomass hydrothermal liquefaction reaction process more suitable for industrial and industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The overall process flow and related equipment schematic diagram of the present invention; Figure 2 Magnified exploded view of the one-way channel. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in conjunction with specific embodiments, but the present invention is not limited to these embodiments. It should be noted that, under the premise of not conflicting, the embodiments described below or the technical features can be arbitrarily combined to form new embodiments. In the present invention, unless otherwise specified, all parts and percentages are mass units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments, if not otherwise specified, are conventional methods in the art.

[0014] As used herein, the terms "comprises," "including," "contains," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0015] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range limited by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any upper range limit or preferred value with any lower range limit or preferred value, regardless of whether this range is disclosed separately. For example, when a range of "1 to 4" is disclosed, the described range should be interpreted as including a range of "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4", etc. When a numerical range is described in this article, unless otherwise stated, this range is intended to include its end values ​​and all integers and fractions within this range.

[0016] The specific embodiments of the present invention are described in detail below.

[0017] 1. Extraction part: Step (1), the material to be separated and the extraction solvent enter the extraction tower from the material inlet and the solvent inlet respectively through the liquid level difference or the pressure difference formed by the centrifugal pump for continuous extraction, and the extraction phase (solution to be rotary evaporated) and the raffinate phase (material after extraction) are continuously separated and output, and then discharged from the extraction tower through the extraction phase outlet and the raffinate phase outlet respectively; Step (2), the extraction phase enters the rotary evaporator through the pressure difference formed between the rotary evaporator and the extraction tower, performs continuous rotary evaporation, and continuously condenses and outputs the recovered solvent; The rotary evaporator is provided with a one-way channel for allowing the recovered solvent to enter the rotary evaporation collection bottle, and can be used to maintain a slight negative pressure system in the rotary evaporation bottle, and the condensed recovered solvent is continuously output to the rotary evaporation collection bottle through the pressure difference formed by the liquid level of the recovered solvent above the one-way channel; A micro-negative pressure channel is provided between the rotary evaporator and the extraction tower to allow the extraction phase to enter the rotary evaporation bottle. The micro-negative pressure channel is connected to the outside atmosphere and is used to stabilize the stratification position between the extraction phase and the raffinate phase in the extraction tower, thereby ensuring the stability of the extraction process. The pressure difference between the extraction phase output by the extraction tower and the rotary evaporation bottle is maintained through the micro-negative pressure channel, thereby realizing the delivery of the extraction solvent to the rotary evaporation bottle through the pressure difference, and then recovering the volatile components of the extraction phase into the rotary evaporation bottle; A loop channel is provided between the rotary evaporator and the extraction tower for allowing the recovered solvent in the rotary evaporation collection bottle to enter the solvent inlet of the extraction tower; a supplementary channel is provided between the rotary evaporator and the vacuum pump for allowing the volatile components discharged by the vacuum pump to enter the rotary evaporation collection bottle.

[0018] (II) Rotary evaporation part: The water bath heating temperature set in the water bath connected to the rotary evaporator is 10°C to 50°C higher than the boiling point of the extraction solvent under a slight negative pressure relative vacuum degree ≤0.1MPa, and the cooling temperature set in the circulating cooler connected to the rotary evaporator is 10°C to 50°C lower than the boiling point of the extraction solvent under a slight negative pressure relative vacuum degree ≤0.1MPa.

[0019] The extraction phase enters the rotary evaporator through the pressure difference formed by the rotary evaporator and the extraction tower for continuous rotary evaporation, and the solvent is continuously condensed and output for recovery; Among them, a micro-negative pressure channel is provided between the rotary evaporator and the extraction tower to allow the extraction phase to enter the rotary evaporation bottle, and the micro-negative pressure relative vacuum degree in the micro-negative pressure channel is maintained at ≤0.1MPa, thereby ensuring that the rotary evaporation process is always carried out under a micro-negative pressure state, and the extraction phase extracted by the extraction tower is transported into the rotary evaporation bottle through the pressure difference formed by the micro-negative pressure to separate the solute and the solvent, and the volatile components of the extraction phase are recovered into the rotary evaporation collection bottle through the pressure difference formed by the micro-negative pressure; The rotary evaporator is provided with a one-way channel for the condensed recovery solvent to enter the rotary evaporation collection bottle, which can maintain a slight negative pressure system in the rotary evaporation bottle, and continuously output the condensed recovery solvent to the rotary evaporation collection bottle through the pressure difference formed by the liquid level of the recovery solvent above the one-way channel; A loop channel is also provided between the rotary evaporator and the extraction tower for allowing the recovered solvent in the rotary evaporation collection bottle to enter the extraction tower, and the relative vacuum degree of the micro-negative pressure in the loop channel is maintained to be ≤ the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel, thereby ensuring that the micro-negative pressure system in the rotary evaporation collection bottle is maintained, and the solvent in the rotary evaporation bottle is continuously recovered through the pressure difference formed by the liquid level difference or the centrifugal pump and enters the extraction tower for extraction operation; A supplementary channel is provided between the rotary evaporator and the vacuum pump to allow the volatile components discharged by the vacuum pump to enter the rotary evaporation collection bottle, and the relative vacuum degree of the micro-negative pressure in the supplementary channel is maintained to be ≤ the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel, thereby ensuring that the micro-negative pressure system in the rotary evaporation collection bottle is maintained, and the volatile components discharged by the vacuum pump are recovered through the pressure difference formed by the micro-negative pressure; A closed space for storing and releasing volatile components is provided in the vacuum pump. The pressure difference formed by the slight negative pressure allows the volatile components in the closed space to be recovered into the rotary evaporation collection bottle, thus reducing the harm to human health and the pollution to the environment caused by the direct discharge of volatile components.

[0020] Example 1: Extraction of benzoic acid from kerosene with water A method for continuous separation by micro-negative pressure rotary evaporation extraction, comprising the following steps: Step (1), the material to be separated (a mixture of kerosene and benzoic acid) and the extraction solvent (water) enter the extraction tower respectively through the liquid level difference for continuous extraction, and are continuously separated and output as an extraction phase (solution to be rotary evaporated) and a raffinate phase (the material after extraction); A micro-negative pressure channel is provided between the rotary evaporator and the extraction tower to allow the extraction phase to enter the rotary evaporation bottle. The micro-negative pressure channel is connected to the outside atmosphere and is used to stabilize the stratification position between the extraction phase and the raffinate phase in the extraction tower, thereby ensuring the stability of the extraction process. The micro-negative pressure channel is used to maintain the pressure difference between the extraction phase output by the extraction tower and the rotary evaporation bottle, thereby realizing the delivery of the extraction solvent (water) to the rotary evaporation bottle through the pressure difference, and then recovering the volatile components of the extraction phase into the rotary evaporation bottle; Step (2), the extraction phase enters the rotary evaporator through the pressure difference formed by the rotary evaporator and the extraction tower for continuous rotary evaporation, and continuously condenses and outputs the recovered solvent (water); The water bath connected to the rotary evaporator was set to a water bath heating temperature of 80°C, and the circulating cooler was set to a cooling temperature of 20°C; The rotary evaporator is provided with a one-way channel for allowing the recovered solvent (water) to enter the rotary evaporation collection bottle; Among them, a micro-negative pressure channel is provided between the rotary evaporator and the extraction tower to allow the extraction phase to enter the rotary evaporation bottle, and a loop channel is also provided to allow the recovered solvent (water) in the rotary evaporation collection bottle to enter the extraction tower; Keep the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel ≤ 0.1MPa, and keep the relative vacuum degree of the micro-negative pressure in the loop channel ≤ the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel; A supplementary channel is provided between the rotary evaporator and the vacuum pump to allow volatile components discharged by the vacuum pump to enter the rotary evaporation collection bottle. A closed space is provided in the vacuum pump to store and release volatile components. By maintaining the relative vacuum degree of the micro-negative pressure in the supplementary channel ≤ the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel, the pressure difference formed by the micro-negative pressure allows the volatile components in the closed space to be recovered into the rotary evaporation collection bottle.

[0021] Example 2: Extraction of biomass oil in water using dichloromethane A method for continuous separation by micro-negative pressure rotary evaporation extraction, comprising the following steps: Step (1), the material to be separated (a mixture of biomass oil and water) and the extraction solvent (dichloromethane) enter the extraction tower through the pressure difference formed by the centrifugal pump for continuous extraction, and are continuously separated and output as an extraction phase (solution to be rotary evaporated) and a raffinate phase (the material after extraction); A micro-negative pressure channel is provided between the rotary evaporator and the extraction tower to allow the extraction phase to enter the rotary evaporation bottle. The micro-negative pressure channel is connected to the outside atmosphere and is used to stabilize the stratification position between the extraction phase and the raffinate phase in the extraction tower, thereby ensuring the stability of the extraction process. The micro-negative pressure channel is used to maintain the pressure difference between the extraction phase output by the extraction tower and the rotary evaporation bottle, thereby realizing the delivery of the extraction solvent (dichloromethane) to the rotary evaporation bottle through the pressure difference, and then recovering the volatile components of the extraction phase into the rotary evaporation bottle; Step (2), the extraction phase enters the rotary evaporator through the pressure difference formed by the rotary evaporator and the extraction tower for continuous rotary evaporation, and continuously condenses and outputs the recovered solvent (dichloromethane); The water bath connected to the rotary evaporator was set to a water bath heating temperature of 50°C, and the circulating cooler was set to a cooling temperature of 0°C; The rotary evaporator is provided with a one-way channel for allowing the recovered solvent (dichloromethane) to enter the rotary evaporation collection bottle; Among them, a micro-negative pressure channel is provided between the rotary evaporator and the extraction tower for the extraction phase to enter the rotary evaporation bottle, and a loop channel is provided for the recovery solvent (dichloromethane) in the rotary evaporation collection bottle to enter the extraction tower; Keep the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel ≤ 0.1MPa, and keep the relative vacuum degree of the micro-negative pressure in the loop channel ≤ the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel; A supplementary channel is provided between the rotary evaporator and the vacuum pump to allow volatile components discharged by the vacuum pump to enter the rotary evaporation collection bottle. A closed space is provided in the vacuum pump to store and release volatile components. By maintaining the relative vacuum degree of the micro-negative pressure in the supplementary channel ≤ the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel, the pressure difference formed by the micro-negative pressure allows the volatile components in the closed space to be recovered into the rotary evaporation collection bottle.

[0022] In further experiments, the micro-negative pressure rotary evaporation extraction combined method in this embodiment was used to separate 40L of oil-water mixture: continuous feeding and separation of the oil phase; not limited by the equipment volume, one-time continuous separation was achieved, and the use and emission of solvent (dichloromethane) was greatly reduced during the separation process, and the manpower input and liquid transfer time between different equipment were reduced, effectively improving the separation efficiency.

[0023] The traditional separation method is to first use an extractor to extract the organic phase, and then use a rotary evaporator to remove the solvent to obtain the oil phase. Due to the limited capacity of each separation equipment, a large amount of raw materials need to be separated multiple times in an intermittent manner. The separation process requires the use and discharge of a large amount of volatile solvents, and requires a lot of manpower investment, and increases the transfer time of different liquids, such as: the raw materials are transferred to the extractor, the organic phase is transferred to the rotary evaporator, and the solvent is transferred and recovered from the rotary evaporation collection bottle.

[0024] The comparative data of extracting biomass oil in water with dichloromethane using the method of this embodiment and the traditional separation method are shown in Table 1 below.

[0025] Table 1:

[0026] Example 3: Extraction of biomass oil in water with ethyl acetate A method for continuous separation by micro-negative pressure rotary evaporation extraction, comprising the following steps: Step (1), the material to be separated (a mixture of biomass oil and water) and the extraction solvent (ethyl acetate) enter the extraction tower for continuous extraction through the pressure difference formed by the centrifugal pump, and are continuously separated and output as an extraction phase (solution to be rotary evaporated) and a raffinate phase (the material after extraction); A micro-negative pressure channel is provided between the rotary evaporator and the extraction tower to allow the extraction phase to enter the rotary evaporation bottle. The micro-negative pressure channel is connected to the outside atmosphere and is used to stabilize the stratification position between the extraction phase and the raffinate phase in the extraction tower, thereby ensuring the stability of the extraction process. The micro-negative pressure channel is used to maintain the pressure difference between the extraction phase output by the extraction tower and the rotary evaporation bottle, thereby realizing the delivery of the extraction solvent (ethyl acetate) to the rotary evaporation bottle through the pressure difference, and then recovering the volatile components of the extraction phase into the rotary evaporation bottle; Step (2), the extraction phase enters the rotary evaporator through the pressure difference formed by the rotary evaporator and the extraction tower for continuous rotary evaporation, and continuously condenses and outputs the recovered solvent (ethyl acetate); The water bath heating temperature of the water bath connected to the rotary evaporator was set to 70°C, and the cooling temperature of the circulating cooler was set to 10°C; The rotary evaporator is provided with a one-way channel for allowing the recovered solvent (ethyl acetate) to enter the rotary evaporation collection bottle; Among them, a micro-negative pressure channel is provided between the rotary evaporator and the extraction tower for allowing the extraction phase to enter the rotary evaporation bottle, and a loop channel is also provided for allowing the recovery solvent (ethyl acetate) in the rotary evaporation collection bottle to enter the extraction tower; Keep the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel ≤ 0.1MPa, and keep the relative vacuum degree of the micro-negative pressure in the loop channel ≤ the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel; A supplementary channel is provided between the rotary evaporator and the vacuum pump to allow volatile components discharged by the vacuum pump to enter the rotary evaporation collection bottle. A closed space is provided in the vacuum pump to store and release volatile components. By maintaining the relative vacuum degree of the micro-negative pressure in the supplementary channel ≤ the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel, the pressure difference formed by the micro-negative pressure allows the volatile components in the closed space to be recovered into the rotary evaporation collection bottle.

[0027] The above embodiments are merely preferred implementations of the present invention. Any simple modification, amendment and substitution of the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A method for continuous separation by micro-negative pressure rotary evaporation extraction, characterized in that: The following steps are involved: Step (1), the material to be separated and the extraction solvent enter the extraction tower from the material inlet and the solvent inlet respectively through the liquid level difference or the pressure difference formed by the centrifugal pump for continuous extraction, and the extraction phase and the raffinate phase are continuously separated and output, and then discharged from the extraction tower through the extraction phase outlet and the raffinate phase outlet respectively; Step (2), the extraction phase enters the rotary evaporator through the pressure difference formed between the rotary evaporator and the extraction tower, performs continuous rotary evaporation, and continuously condenses and outputs the recovered solvent; The rotary evaporator is provided with a one-way channel for allowing the recovered solvent to enter the rotary evaporation collection bottle, and can be used to maintain a slight negative pressure system in the rotary evaporation bottle, and the condensed recovered solvent is continuously output to the rotary evaporation collection bottle through the pressure difference formed by the liquid level of the recovered solvent above the one-way channel; A micro-negative pressure channel is provided between the rotary evaporator and the extraction tower to allow the extraction phase to enter the rotary evaporation bottle. The micro-negative pressure channel is connected to the outside atmosphere and is used to stabilize the stratification position between the extraction phase and the raffinate phase in the extraction tower to ensure the stability of the extraction process and to maintain the pressure difference between the extraction phase output by the extraction tower and the rotary evaporation bottle, transport the extraction solvent to the rotary evaporation bottle, and recover the volatile components of the extraction phase into the rotary evaporation bottle; A loop channel is provided between the rotary evaporator and the extraction tower for allowing the recovered solvent in the rotary evaporation collection bottle to enter the solvent inlet of the extraction tower; a supplementary channel is provided between the rotary evaporator and the vacuum pump for allowing the volatile components discharged by the vacuum pump to enter the rotary evaporation collection bottle.

2. The method of continuous separation by micro-negative pressure rotary evaporation extraction according to claim 1, characterized in that: In step (2), the water bath heating temperature set in the water bath pot connected to the rotary evaporator is 10°C to 50°C higher than the boiling point of the extraction solvent at a slight negative pressure relative vacuum degree ≤0.1 MPa, and the cooling temperature set in the circulating cooler connected to the rotary evaporator is 10°C to 50°C lower than the boiling point of the extraction solvent at a slight negative pressure relative vacuum degree ≤0.1 MPa.

3. The method of continuous separation by micro-negative pressure rotary evaporation extraction according to claim 1, characterized in that: Step (2), maintaining the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel ≤ 0.1 MPa.

4. The method of continuous separation by micro-negative pressure rotary evaporation extraction according to claim 1, characterized in that: Step (2), maintaining the relative vacuum degree of the micro-negative pressure in the loop channel ≤ the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel.

5. The method of continuous separation by micro-negative pressure rotary evaporation extraction according to claim 1, characterized in that: In step (2), a closed space for storing and releasing volatile components is provided in the vacuum pump, and the volatile components in the closed space are recovered into the rotary evaporation collection bottle by maintaining the relative vacuum degree of the micro-negative pressure in the supplementary channel ≤ the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel.

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