A method for continuous separation of micro-negative pressure rotary evaporation extraction combined with continuous separation

Abstract

The present application belongs to the field of chemical separation technology, and particularly relates to a method for continuous separation of micro-negative pressure rotary evaporation extraction combination, comprising the following steps: (1) continuously extracting a material to be separated and an extraction solvent to separate an extraction phase and a raffinate phase; a gas pressure channel is arranged in the micro-negative pressure channel to connect the extraction phase with the outside atmosphere; (2) the extraction phase enters a rotary evaporator for continuous rotary evaporation through a pressure difference between a rotary evaporation bottle and an extraction tower, and is condensed and output to recover the solvent; a one-way channel is arranged in the rotary evaporator to make the recovered solvent enter a rotary evaporation collection bottle, a micro-negative pressure channel is arranged between the rotary evaporator and the extraction tower to make the extraction phase enter the rotary evaporation bottle, and a loop channel is arranged to make the recovered solvent in the rotary evaporation collection bottle enter the extraction tower; a supplementary channel is arranged between the rotary evaporator and a vacuum pump to make volatile components discharged by the vacuum pump enter the rotary evaporation collection bottle. The present application improves the efficiency of material separation, reduces the cost, and is healthy and environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of chemical separation technology, specifically relating to a continuous separation method using a combination of micro-negative pressure rotary evaporation and extraction. Background Technology

[0002] Material separation is a crucial chemical process, requiring specialized equipment and significant energy input. Separation techniques based on differences in liquid boiling points primarily include distillation or rectification, while techniques based on the polarity differences between oil and water phases mainly include extraction. Distillation equipment is simple, but it cannot achieve continuous material input and output. Rectification can achieve continuous material input and output, but requires more advanced equipment. Generally, material separation requires multiple steps, but the different separation methods often lack synergy, resulting in low overall efficiency, consuming substantial labor and energy costs, and posing certain safety and health hazards. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a continuous separation method using micro-negative pressure rotary evaporation extraction, which improves the material separation efficiency in the hydrothermal liquefaction process of biomass, reduces costs, and meets health and environmental protection requirements.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for continuous separation using micro-negative pressure rotary evaporation extraction combined with micro-negative pressure includes the following steps:

[0006] 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 continuously separate and output the extract phase (solution to be rotary evaporated) and the raffinate phase (material after extraction), and then discharge them from the extraction tower through the extract phase outlet and the raffinate phase outlet respectively.

[0007] In step (2), the extract phase enters the rotary evaporator through the pressure difference formed between the rotary evaporation flask and the extraction tower, and is continuously rotary evaporated and the solvent is continuously condensed and output for recovery.

[0008] The rotary evaporator is equipped with a one-way channel that allows 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. Through the pressure difference formed by the liquid level of the recovered solvent above the one-way channel, the condensed recovered solvent is continuously output to the rotary evaporation collection bottle.

[0009] A micro-negative pressure channel is provided between the rotary evaporator and the extraction column to allow the extract phase to enter the rotary evaporating flask. The micro-negative pressure channel is connected to the outside atmosphere and is used to stabilize the stratification position between the extract phase and the raffinate phase in the extraction column, thereby ensuring the stability of the extraction process. The micro-negative pressure channel also maintains the pressure difference between the extract phase output from the extraction column and the rotary evaporating flask, thereby enabling the extraction solvent to be transported to the rotary evaporating flask through the pressure difference, and thus recovering the volatile components of the extract phase to the rotary evaporating flask.

[0010] A loop channel is provided between the rotary evaporator and the extraction tower to allow 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 to allow the volatile components discharged by the vacuum pump to enter the rotary evaporation collection bottle.

[0011] In a preferred example, in step (2), 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 micro-negative pressure relative vacuum of ≤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 micro-negative pressure relative vacuum of ≤0.1MPa.

[0012] In a preferred example, step (2) maintains the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel ≤0.1MPa.

[0013] In a preferred example, step (2) maintains 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.

[0014] In a preferred example, in step (2), the vacuum pump is provided with a sealed space for storing and releasing volatile components. By maintaining the relative vacuum degree of the micro-negative pressure in the replenishment 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 sealed space to be recovered into the rotary evaporation collection bottle.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0016] 1. Improved efficiency: The continuous micro-negative pressure rotary evaporation-extraction combination improves the efficiency of substance separation; this is mainly reflected in two aspects: First, all kinds of substances are continuously transported through 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 pressure distillation or rectification.

[0017] 2. Cost Reduction: Continuous micro-negative pressure rotary evaporation-extraction coupling reduces the cost of substance separation, mainly in two aspects: First, the micro-negative pressure design enables the ingenious combination of the extraction tower and the rotary evaporator, reducing the cost of operating the rotary evaporation vacuum pump and various liquid pumping; second, the micro-negative pressure system recovers the solvent discharged from the rotary evaporator and vacuum pump, as well as the volatile components transported in the extraction tower, to the rotary evaporation collection bottle, and continuously recovers the solvent in the rotary evaporation collection bottle to the extraction tower for extraction operation through liquid level difference or centrifugal pump, thereby reducing the overall solvent consumption.

[0018] 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.

[0019] This invention employs a simplified channel structure, making the separation of substances during the hydrothermal liquefaction reaction of biomass more suitable for industrial and commercial applications. Attached Figure Description

[0020] Figure 1 The overall process flow and related equipment diagram of this invention;

[0021] Figure 2 Enlarged view of the explosion at the one-way passage. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is further described in conjunction with specific embodiments. However, this invention is not limited to these embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. In this invention, unless otherwise specified, all parts and percentages are units of mass, and the equipment and raw materials used are commercially available or commonly used in the art. Unless otherwise specified, the methods in the following embodiments are conventional methods in the art.

[0023] The terms “comprising,” “including,” “containing,” or any other variations thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0024] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether such range is disclosed individually. For example, when the range “1 to 4” is disclosed, the described range should be interpreted as including ranges “1 to 4”, “1 to 3”, “1 to 2”, “1 to 2 and 4”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0025] The specific embodiments of the present invention will be described in detail below.

[0026] (a) Extraction section:

[0027] 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 continuously separate and output the extract phase (solution to be rotary evaporated) and the raffinate phase (material after extraction), and then discharge them from the extraction tower through the extract phase outlet and the raffinate phase outlet respectively.

[0028] In step (2), the extract phase enters the rotary evaporator through the pressure difference formed between the rotary evaporation flask and the extraction tower, and is continuously rotary evaporated and the solvent is continuously condensed and output for recovery.

[0029] The rotary evaporator is equipped with a one-way channel that allows 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. 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.

[0030] A micro-negative pressure channel is provided between the rotary evaporator and the extraction column to allow the extract phase to enter the rotary evaporating flask. The micro-negative pressure channel is connected to the outside atmosphere and is used to stabilize the stratification position between the extract phase and the raffinate phase in the extraction column, thereby ensuring the stability of the extraction process. The micro-negative pressure channel also maintains the pressure difference between the extract phase output from the extraction column and the rotary evaporating flask, thereby enabling the extraction solvent to be transported to the rotary evaporating flask through the pressure difference, and thus recovering the volatile components of the extract phase to the rotary evaporating flask.

[0031] A loop channel is provided between the rotary evaporator and the extraction tower to allow 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 to allow the volatile components discharged by the vacuum pump to enter the rotary evaporation collection bottle.

[0032] (II) Rotary Evaporation Section:

[0033] The water bath heating temperature set in the water bath connected to the rotary evaporator is 10℃~50℃ higher than the boiling point of the extraction solvent under a slight negative pressure relative vacuum degree ≤0.1MPa. The cooling temperature set in the circulating cooler connected to the rotary evaporator is 10℃~50℃ lower than the boiling point of the extraction solvent under a slight negative pressure relative vacuum degree ≤0.1MPa.

[0034] The extract phase enters the rotary evaporator through the pressure difference formed between the rotary evaporation flask and the extraction column for continuous rotary evaporation, and the solvent is continuously condensed and output for recovery.

[0035] The rotary evaporator is connected to the extraction column by a micro-negative pressure channel that allows the extract phase to enter the rotary evaporation flask. The micro-negative pressure channel maintains a relative vacuum of ≤0.1MPa, thereby ensuring that the rotary evaporation process is always carried out under micro-negative pressure. The pressure difference formed by the micro-negative pressure transports the extract phase extracted by the extraction column into the rotary evaporation flask for separation of solute and solvent, and recovers the volatile components of the extract phase to the rotary evaporation collection flask through the pressure difference formed by the micro-negative pressure.

[0036] The rotary evaporator is equipped with a one-way channel that allows the condensed recovered solvent to enter the rotary evaporation collection bottle. This maintains 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.

[0037] A loop channel is also provided between the rotary evaporator and the extraction tower to allow the recovered solvent in the rotary evaporation collection bottle to enter the extraction tower. The relative vacuum degree of the micro negative pressure in the loop channel is kept ≤ the relative vacuum degree of the micro negative pressure in the micro negative pressure channel, thereby ensuring the maintenance of the micro negative pressure system in the rotary evaporation collection bottle. The solvent in the rotary evaporation bottle is continuously recovered and entered into the extraction tower for extraction operation through the liquid level difference or the pressure difference formed by the centrifugal pump.

[0038] A replenishment channel is provided between the rotary evaporator and the vacuum pump, allowing the volatile components discharged by the vacuum pump to enter the rotary evaporation collection bottle. The relative vacuum degree of the micro-negative pressure in the replenishment channel is kept ≤ the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel, thereby ensuring the maintenance of the micro-negative pressure system in the rotary evaporation collection bottle, and recovering the volatile components discharged by the vacuum pump through the pressure difference formed by the micro-negative pressure.

[0039] The vacuum pump has a sealed space for storing and releasing volatile components. The pressure difference formed by the slight negative pressure allows the volatile components in the sealed space to be recovered into the rotary evaporation collection bottle, reducing the harm to human health and environmental pollution caused by the direct discharge of volatile components.

[0040] Example 1: Extraction of benzoic acid from kerosene with water

[0041] A method for continuous separation using micro-negative pressure rotary evaporation extraction combined with micro-negative pressure includes the following steps:

[0042] In step (1), the material to be separated (a mixture of kerosene and benzoic acid) and the extraction solvent (water) are introduced into the extraction tower through the liquid level difference for continuous extraction, and are continuously separated and output as the extract phase (the solution to be rotary evaporated) and the raffinate phase (the material after extraction).

[0043] A micro-negative pressure channel is provided between the rotary evaporator and the extraction column to allow the extract phase to enter the rotary evaporating flask. The micro-negative pressure channel is connected to the external atmosphere and is used to stabilize the stratification position between the extract phase and the raffinate phase in the extraction column, thereby ensuring the stability of the extraction process. The micro-negative pressure channel also maintains the pressure difference between the extract phase output from the extraction column and the rotary evaporating flask, thereby enabling the extraction solvent (water) to be transported to the rotary evaporating flask through the pressure difference, and thus recovering the volatile components of the extract phase to the rotary evaporating flask.

[0044] In step (2), the extract phase enters the rotary evaporator through the pressure difference formed between the rotary evaporation flask and the extraction tower for continuous rotary evaporation, and the solvent (water) is continuously condensed and output for recovery.

[0045] The water bath of the rotary evaporator is set to a heating temperature of 80°C, and the circulating cooler is set to a cooling temperature of 20°C.

[0046] The rotary evaporator is equipped with a one-way channel that allows the recovered solvent (water) to enter the rotary evaporation collection bottle;

[0047] Among them, there is a micro-negative pressure channel between the rotary evaporator and the extraction column to allow the extract phase to enter the rotary evaporation flask, and there is also a loop channel to allow the recovered solvent (water) in the rotary evaporation collection flask to enter the extraction column.

[0048] Maintain the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel ≤ 0.1MPa, and maintain 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;

[0049] A supplementary channel is provided between the rotary evaporator and the vacuum pump, allowing the volatile components discharged by the vacuum pump to enter the rotary evaporation collection bottle. The vacuum pump has a sealed space for storing the released 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 sealed space to be recovered into the rotary evaporation collection bottle.

[0050] Example 2: Extraction of biomass oil from water using dichloromethane

[0051] A method for continuous separation using micro-negative pressure rotary evaporation extraction combined with micro-negative pressure includes the following steps:

[0052] In step (1), the material to be separated (a mixture of biomass oil and water) and the extraction solvent (dichloromethane) are introduced into the extraction tower through the pressure difference formed by the centrifugal pump for continuous extraction, and are continuously separated and output as the extract phase (the solution to be rotary evaporated) and the raffinate phase (the material after extraction).

[0053] A micro-negative pressure channel is provided between the rotary evaporator and the extraction column to allow the extract phase to enter the rotary evaporating flask. The micro-negative pressure channel is connected to the outside atmosphere and is used to stabilize the stratification position between the extract phase and the raffinate phase in the extraction column, thereby ensuring the stability of the extraction process. The micro-negative pressure channel also maintains the pressure difference between the extract phase output from the extraction column and the rotary evaporating flask, thereby enabling the extraction solvent (dichloromethane) to be transported to the rotary evaporating flask through the pressure difference, and thus recovering the volatile components of the extract phase to the rotary evaporating flask.

[0054] In step (2), the extract phase enters the rotary evaporator through the pressure difference formed between the rotary evaporator flask and the extraction tower for continuous rotary evaporation, and the solvent (dichloromethane) is continuously condensed and output for recovery.

[0055] The water bath of the rotary evaporator is set to a heating temperature of 50°C, and the circulating cooler is set to a cooling temperature of 0°C.

[0056] The rotary evaporator is equipped with a one-way channel that allows the recovered solvent (dichloromethane) to enter the rotary evaporation collection bottle;

[0057] Among them, there is a micro-negative pressure channel between the rotary evaporator and the extraction column to allow the extract phase to enter the rotary evaporation flask, and there is also a loop channel to allow the recovered solvent (dichloromethane) in the rotary evaporation collection flask to enter the extraction column.

[0058] Maintain the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel ≤ 0.1MPa, and maintain 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;

[0059] A supplementary channel is provided between the rotary evaporator and the vacuum pump, allowing the volatile components discharged by the vacuum pump to enter the rotary evaporation collection bottle. The vacuum pump has a sealed space for storing the released 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 sealed space to be recovered into the rotary evaporation collection bottle.

[0060] Further experiments were conducted using the micro-negative pressure rotary evaporation extraction method described in this embodiment to separate a 40L oil-water mixture: continuous feeding and separation of the oil phase; not limited by equipment volume, achieving continuous separation in one go; greatly reducing the use and emission of solvent (dichloromethane) during the separation process, as well as reducing manpower input and liquid transfer time between different devices, effectively improving separation efficiency.

[0061] Traditional separation methods involve first extracting the organic phase using an extractor, then removing the solvent using a rotary evaporator to obtain the oil phase. Due to the limited capacity of each separation unit, large quantities of raw materials require multiple intermittent separations. The separation process uses and discharges large amounts of volatile solvents, requires significant manpower, and increases the transfer time between different liquids; for example, the raw material is transferred to the extractor, the organic phase to the rotary evaporator, and the solvent is transferred and recovered from the rotary evaporation collection bottle.

[0062] The comparative data of extracting biomass oil from water using the method of this embodiment and the traditional separation method using dichloromethane are shown in Table 1 below.

[0063] Table 1:

[0064]

[0065] Example 3: Extraction of biomass oil from water using ethyl acetate

[0066] A method for continuous separation using micro-negative pressure rotary evaporation extraction combined with micro-negative pressure includes the following steps:

[0067] In step (1), the material to be separated (a mixture of biomass oil and water) and the extraction solvent (ethyl acetate) are continuously extracted into the extraction tower through the pressure difference formed by the centrifugal pump, and are continuously separated and output as the extract phase (the solution to be rotary evaporated) and the raffinate phase (the material after extraction).

[0068] A micro-negative pressure channel is provided between the rotary evaporator and the extraction column to allow the extract phase to enter the rotary evaporating flask. The micro-negative pressure channel is connected to the outside atmosphere and is used to stabilize the stratification position between the extract phase and the raffinate phase in the extraction column, thereby ensuring the stability of the extraction process. The micro-negative pressure channel also maintains the pressure difference between the extract phase output from the extraction column and the rotary evaporating flask, thereby enabling the extraction solvent (ethyl acetate) to be transported to the rotary evaporating flask through the pressure difference, and the volatile components of the extract phase to be recovered to the rotary evaporating flask.

[0069] In step (2), the extract phase enters the rotary evaporator through the pressure difference formed between the rotary evaporator flask and the extraction tower for continuous rotary evaporation, and the solvent (ethyl acetate) is continuously condensed and output for recovery.

[0070] The water bath of the rotary evaporator is set to a heating temperature of 70°C, and the circulating cooler is set to a cooling temperature of 10°C.

[0071] The rotary evaporator is equipped with a one-way channel that allows the recovered solvent (ethyl acetate) to enter the rotary evaporation collection bottle;

[0072] Among them, there is a micro-negative pressure channel between the rotary evaporator and the extraction column to allow the extract phase to enter the rotary evaporation flask, and there is also a loop channel to allow the recovered solvent (ethyl acetate) in the rotary evaporation collection flask to enter the extraction column.

[0073] Maintain the relative vacuum degree of the micro-negative pressure in the micro-negative pressure channel ≤ 0.1MPa, and maintain 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;

[0074] A supplementary channel is provided between the rotary evaporator and the vacuum pump, allowing the volatile components discharged by the vacuum pump to enter the rotary evaporation collection bottle. The vacuum pump has a sealed space for storing the released 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 sealed space to be recovered into the rotary evaporation collection bottle.

[0075] The above embodiments are merely preferred embodiments of the present invention. Any simple modifications, alterations, and substitutions made to the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A method for continuous separation using a combination of micro-negative pressure rotary evaporation and extraction, characterized in that, Includes 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 continuously separate and output the extract phase and the raffinate phase, and then discharge them from the extraction tower through the extract phase outlet and the raffinate phase outlet respectively. In step (2), the extract phase enters the rotary evaporator through the pressure difference formed between the rotary evaporation flask and the extraction tower, and is continuously rotary evaporated and the solvent is continuously condensed and output for recovery. The rotary evaporator is equipped with a one-way channel that allows 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. Through the pressure difference formed by the liquid level of the recovered solvent above the one-way channel, the condensed recovered solvent is continuously output to the rotary evaporation collection bottle. A micro-negative pressure channel is provided between the rotary evaporator and the extraction column to allow the extract phase to enter the rotary evaporating flask. The micro-negative pressure channel is connected to the outside atmosphere and is used to stabilize the stratification position between the extract phase and the raffinate phase in the extraction column, ensure the stability of the extraction process, maintain the pressure difference between the extract phase output from the extraction column and the rotary evaporating flask, deliver the extraction solvent to the rotary evaporating flask, and recover the volatile components of the extract phase to the rotary evaporating flask. A loop channel is provided between the rotary evaporator and the extraction column to allow the recovered solvent in the rotary evaporation collection bottle to enter the solvent inlet of the extraction column; a replenishment 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. The water bath temperature set in the rotary evaporator is 10°C to 50°C higher than the boiling point of the extraction solvent under a micro-negative pressure relative vacuum of ≤0.1MPa. 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 micro-negative pressure relative vacuum of ≤0.1MPa. The micro-negative pressure relative vacuum in the micro-negative pressure channel is maintained at ≤0.1MPa. The micro-negative pressure relative vacuum in the loop channel is maintained at ≤0.1MPa. The vacuum pump has a sealed space for storing and releasing volatile components. By maintaining the micro-negative pressure relative vacuum in the replenishment channel at ≤0.1MPa, the pressure difference of the micro-negative pressure allows the volatile components in the sealed space to be recovered into the rotary evaporation collection bottle.

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