WO2023016240A1

WO2023016240A1 - Supercritical carbon dioxide drying apparatus and application thereof, and supercritical carbon dioxide drying method

Info

Publication number: WO2023016240A1
Application number: PCT/CN2022/107779
Authority: WO
Inventors: 王蕴宏; 温广河; 杜泉岭; 李琴; 钱向华; 晁华鑫; 田雷
Original assignee: 爱彼爱和新材料有限公司
Priority date: 2021-08-10
Filing date: 2022-07-26
Publication date: 2023-02-16
Also published as: CN115704647A

Abstract

The present invention relates to the field of supercritical drying, and disclosed are a supercritical carbon dioxide drying apparatus and an application thereof, and a supercritical carbon dioxide drying method. The apparatus comprises a supercritical treatment unit, a drying unit, and a separation unit that are sequentially communicated by means of pipelines; the drying unit comprises 3-12 drying kettles provided in parallel; the supercritical treatment unit is used for performing supercritical treatment on condensed carbon dioxide to obtain treated carbon dioxide; the drying unit is used for enabling the treated carbon dioxide to be in contact with a material to be dried to perform drying treatment to obtain an effluent I; and the separation unit is used for separating the effluent I to obtain recyclable carbon dioxide and an effluent II. The supercritical carbon dioxide drying apparatus and drying method provided by the present invention have high drying efficiency and low power consumption.

Description

A kind of supercritical carbon dioxide drying device and its application and supercritical carbon dioxide drying method

Cross References to Related Applications

This application claims the benefit of Chinese patent application 202110913059.X filed on August 10, 2021, the contents of which are incorporated herein by reference.

technical field

The invention relates to the field of supercritical drying, in particular to a supercritical carbon dioxide drying device and its application in preparing airgel and a supercritical carbon dioxide drying method.

Background technique

At present, the carbon dioxide in the traditional supercritical carbon dioxide drying process usually adopts the feeding method of bottom in and top out. If it is completely taken out of the drying kettle, the aforementioned problems can only be solved by increasing the extraction time, resulting in a decrease in work efficiency and an increase in energy consumption.

As we all know, supercritical carbon dioxide at a certain pressure and temperature has a certain solubility for the solute, and the drying kettles in the prior art are usually connected in series, because the solute cannot be completely taken out by carbon dioxide, which will inevitably lead to the next step. The carbon dioxide in the drying kettle contains certain solutes, so that the amount of solutes dissolved in the carbon dioxide in the next drying kettle is reduced. The more the number of drying tanks is, the amount of solute dissolved in carbon dioxide will gradually decrease, so that the product quality of the latter drying tank will be inferior to that of the previous drying tank. The current solution to this phenomenon is to increase the extraction time to ensure the pass rate of the product, but this undoubtedly results in a decrease in efficiency and an increase in cost.

At the same time, the flow rate of carbon dioxide in the traditional supercritical carbon dioxide drying process is usually kept constant. However, experiments have proved that in the early stage of drying, because the material to be dried contains more liquid substances, the carbon dioxide introduced at the beginning can bring out more Liquid substances; however, the liquid substances have been greatly reduced in the later stage of drying. At this time, it is meaningless to keep the flow rate of carbon dioxide constant. And this will undoubtedly cause waste, resulting in an increase in energy consumption.

Contents of the invention

The purpose of the invention is to overcome the problems of low drying efficiency and high energy consumption in the prior art.

In order to achieve the above object, a first aspect of the present invention provides a supercritical carbon dioxide drying device, the device comprising:

A supercritical treatment unit, a drying unit and a separation unit connected in sequence through pipelines, the drying unit contains 3-12 drying kettles arranged in parallel;

The supercritical treatment unit is used to perform supercritical treatment on the condensed carbon dioxide to obtain treated carbon dioxide;

The drying unit is used to contact the treated carbon dioxide with the material to be dried for drying treatment to obtain effluent I;

The separation unit is used to separate the effluent I to obtain recyclable carbon dioxide and effluent II;

The arrangement of the pipelines in the drying unit enables the treated carbon dioxide to be introduced from the upper part of each of the drying tanks and drawn out from the lower part of each of the drying tanks.

The second aspect of the present invention provides the application of the supercritical carbon dioxide drying device described in the first aspect in the preparation of airgel.

A third aspect of the present invention provides a supercritical carbon dioxide drying method, which is carried out in the supercritical carbon dioxide drying device described in the aforementioned first aspect, comprising:

(1) introducing condensed carbon dioxide into a supercritical treatment unit for supercritical treatment to obtain treated carbon dioxide;

(2) introducing the treated carbon dioxide into each drying tank arranged in parallel in the drying unit to contact with the material to be dried for drying treatment to obtain effluent I;

(3) The effluent I is introduced into a separation unit for separation to obtain carbon dioxide and effluent II which can be recycled.

The supercritical carbon dioxide drying device provided by the invention has the following beneficial effects:

(1) The supercritical carbon dioxide drying device provided by the present invention adopts the feeding mode of top in and bottom out, which can change the gravity of the solute from resistance to power.

(2) The drying stills in the supercritical carbon dioxide drying device provided by the present invention adopt a parallel mode, so that each drying still works independently, which can effectively solve the problem that the content of solute in the carbon dioxide decreases with the increase of the number of drying stills problems, thereby improving drying efficiency.

(3) The supercritical carbon dioxide drying device provided by the present invention can gradually reduce the flow of carbon dioxide by adopting a stepwise flow of carbon dioxide, thereby reducing energy consumption.

(4) The supercritical carbon dioxide drying device provided by the present invention has the advantage of adjustable production scale, which can be adjusted according to actual production conditions.

Description of drawings

Fig. 1 is a diagram of a supercritical carbon dioxide drying device in a preferred embodiment provided by the present invention.

Explanation of reference signs

Y1-storage unit E1-condensing unit I P1-boosting pump E2-heat exchanger I

R1-drying kettle R2-drying kettle R3-drying kettle

E3-Heat Exchanger II S1-Separation Kettle E4-Heat Exchanger II S2-Separation Kettle

Y2-recovery unit I Y3-recovery unit II C1 compressor pump E5-condensing unit II

Detailed ways

Neither the endpoints nor any values of the ranges disclosed herein are limited to such precise ranges or values, and these ranges or values are understood to include values approaching these ranges or values. For numerical ranges, between the endpoints of each range, between the endpoints of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, these values Ranges should be considered as specifically disclosed herein.

As previously mentioned, the first aspect of the present invention provides a supercritical carbon dioxide drying device, the device comprising:

The inventors of the present invention found that, compared with the prior art, the drying device provided by the present invention has higher drying efficiency and lower energy consumption.

Preferably, the number of drying kettles arranged in parallel in the drying unit is 3.

Preferably, the supercritical treatment unit contains a booster pump and a heat exchanger 1 connected in sequence. It should be noted that the present invention has no special limitation on the number of booster pumps and heat exchangers 1, and those skilled in the art can select in combination with known technologies in the art, and the present invention will not be described in detail here. It should not be understood by the skilled person as a limitation of the present invention. The present invention exemplarily provides a preferred implementation mode. In order to achieve higher drying efficiency and lower energy consumption, the number of booster pumps and heat exchangers I in the present invention are respectively one, and a booster pump is used to The pressure pump is in the front, and the heat exchanger I is connected in series in the back.

Preferably, the separation unit contains a heat exchanger II and a separation tank connected in sequence, and the heat exchanger II communicates with the drying tank.

Further preferably, the number of the heat exchanger II is at least 2, and the number of the separation tank is at least 2. In the present invention, the connection mode between the two heat exchangers II and the two separation tanks can be heat exchanger II, and the separation tank, heat exchanger II, and separation tank are connected in series in sequence, wherein the heat exchanger II is connected to the drying tank.

Preferably, the device also includes a recovery unit I and a recovery unit II, the recovery unit I is arranged downstream of the separation unit and communicates with the separation tank, and the recovery unit II is arranged in parallel with the separation unit Downstream of the drying unit, the recovery unit I is used to recover the effluent II, and the recovery unit II is used to recover a part of the recyclable carbon dioxide.

Preferably, the device further comprises a storage unit arranged upstream of the supercritical treatment unit, the storage unit being capable of storing carbon dioxide.

According to a preferred embodiment, the device also includes a condensation unit I arranged between the storage unit and the supercritical processing unit, the condensation unit I is used to condense the carbon dioxide.

According to another preferred embodiment, the device further includes a condensation unit II arranged between the storage unit and the recovery unit II, the condensation unit II is used to condense the remaining part of the recyclable carbon dioxide , the raw material condensed by the condensation unit II is recycled to the storage unit.

It should be noted that the present invention has no special restrictions on the types of drying tanks, separation tanks, and heat exchangers. Those skilled in the art can select them in combination with known technologies in the art. The present invention will not be described in detail here. It should not be understood by the skilled person as a limitation of the present invention.

It should be noted that the present invention has no particular limitation on the types and quantities of equipment used in the storage unit, condensation unit, and recovery unit, and those skilled in the art can select in combination with known technologies in the art, and the present invention herein No more detailed description, those skilled in the art should not understand that the present invention is limited.

It should be noted that various control valves known to those skilled in the art may be provided in the circulation passage of the device of the present invention to control the flow of the carbon dioxide fluid.

It should be noted that all pressure vessels (such as storage unit, drying tank, separating tank, heat exchanger, condensation unit) in the device of the present invention can have independent emptying valves, and can also have pressure gauges, temperature gauge to show the pressure and temperature inside the unit. The carbon dioxide storage unit and the carbon dioxide recovery unit can also have a carbon dioxide volume meter to display the volume of liquid carbon dioxide in the device. Each drying vessel may have a flow meter to indicate the flow of carbon dioxide introduced into each drying vessel. In order to realize the cyclic process, each device in the device of the present invention can be set or set in a matching manner according to specific needs.

It should be noted that in the separation tank of the device of the present invention, materials capable of absorbing solvent (solvent in the material to be dried), including but not limited to molecular sieves, can be placed in the separation tank, and the materials are regularly replaced and activated.

The supercritical carbon dioxide drying device of the present invention is exemplarily described below in conjunction with FIG. 1 .

Lead the carbon dioxide raw material from the storage unit Y1 to the condensation unit I E1 for condensation treatment I, introduce the condensed carbon dioxide into the pressurization pump P1 for pressurization treatment, and introduce the pressurized carbon dioxide into the heat exchanger I E2 In order to obtain supercritical carbon dioxide, supercritical carbon dioxide is introduced into drying kettle R1, drying kettle R2 and drying kettle R3 respectively to carry out drying treatment with the materials to be dried contained therein (it can be introduced simultaneously or individually. ), after the drying treatment, the carbon dioxide carrying the solvent is introduced into the heat exchanger II E3 and/or the heat exchanger II E4 for heat treatment, and after the heat treatment, it is introduced into the separation kettle S1 and/or the separation kettle S2 for separation, and the The separated effluent II is introduced into the recovery unit I Y2 for recovery treatment, a part of the recyclable carbon dioxide is introduced into the recovery unit IIY3, and the remaining part is compressed by the compressor pump C1 and then introduced into the condensation unit II E5 for condensation treatment II, the carbon dioxide after the condensation treatment II is recycled to the storage unit Y1 for recycling. Among them, the carbon dioxide in the recovery unit IIY3 can be introduced into the condensation unit II E5 after being compressed by the compression pump C1 when the device is not in operation for condensation treatment II, and the carbon dioxide after the condensation treatment II can be introduced into the storage unit Y1 for recycling .

As mentioned above, the second aspect of the present invention provides the application of the supercritical carbon dioxide drying device described in the aforementioned first aspect in the preparation of aerogel.

As previously mentioned, the third aspect of the present invention provides a supercritical carbon dioxide drying method, which is carried out in the supercritical carbon dioxide drying device described in the aforementioned first aspect, comprising:

Preferably, the method further includes, before step (1), introducing the carbon dioxide raw material in the storage unit into the condensation unit I for condensation treatment I, so as to obtain the condensed carbon dioxide. The purpose of the condensation treatment I is to prevent the carbon dioxide from vaporizing, so as to ensure that the booster pump can deliver the carbon dioxide to each of the drying tanks.

According to a preferred embodiment, the method also includes, after performing the step (3), introducing the effluent II into the recovery unit I for recovery treatment, introducing a part of the recyclable carbon dioxide into To the recovery unit II and the remaining part of the recyclable carbon dioxide is recycled to the condensation unit II for condensation treatment II, and the material obtained after the condensation treatment II is introduced into the storage unit.

Preferably, the volume ratio of the part of the recyclable carbon dioxide to the remaining part of the recyclable carbon dioxide is 1:0.83-0.95. The inventors of the present invention found that in this preferred situation, the drying method provided by the present invention has lower energy consumption.

According to another preferred embodiment, in step (2), the conditions of the drying treatment in each of the drying tanks are the same or different, each independently satisfying at least: controlling the flow rate of the treated carbon dioxide to be 800 -1500L/h.

In order to achieve higher drying efficiency and lower energy consumption, preferably, the conditions of the drying treatment in each of the drying tanks independently at least meet:

When the drying treatment is carried out for 0-2h, the carbon dioxide flow rate after the treatment is controlled to be 1200-1500L/h;

When the drying treatment is carried out for 2-4 hours, the carbon dioxide flow rate after the treatment is controlled to be 1000-1200L/h;

When the drying treatment is carried out for 4-6 hours, the flow rate of carbon dioxide after the treatment is controlled to be 800-1000 L/h.

It should be noted that, in the device of the present invention, there are no special restrictions on the pressure and temperature of the devices in the storage unit, the drying unit, and the separation unit. Exemplarily, the pressure in the storage unit device can be 4-5MPa, the temperature is 7-15°C, the pressure in the drying unit device can be 13-16MPa, and the temperature is 50-70°C, and the pressure in the separation unit device can be 4-8MPa, the temperature is 40-60°C.

It should be noted that all timing starting points of the present invention are when opening the inlet valve of the drying kettle and beginning to introduce the treated carbon dioxide. The time when the drying treatment is carried out for 0-2 hours refers to when the inlet valve of the drying kettle is opened and the treated carbon dioxide is introduced to the time when the treated carbon dioxide is introduced for 2 hours. Similarly, when the drying treatment is performed for 2-4 hours, it refers to introducing the treated carbon dioxide for 2 hours to introducing the treated carbon dioxide for 4 hours. Those skilled in the art can deduce similarly, and the present invention will not repeat them one by one here.

The drying treatment in the present invention preferably adopts batch drying treatment, that is, after the product is dried, the inlet valve of the drying kettle is temporarily closed to carry out the product loading and unloading treatment.

The present invention will be described in detail below by way of examples.

In the following example, the preparation method of the wet gel to be dried: refer to the method in Example 1 in CN103118979A to prepare the wet gel to be dried.

Carbon dioxide storage tank: volume is 10m ³ .

Carbon dioxide drying kettle: volume is 3m ³ .

Separation kettle: volume is 3m ³ .

Solvent recovery tank: volume is 1m ³ .

Carbon dioxide recovery tank: volume is 3m ³ .

Example 1

Put 750L of wet gel to be dried in each drying kettle, introduce the condensed carbon dioxide into each drying kettle, and carry out drying treatment. Separation treatment is carried out in the kettle. When the solvent liquid level in the solvent recovery tank reaches the set level (4/5 of the equipment volume), the solvent recovery treatment is carried out. After the separation treatment, the drying kettle is first pressured with the carbon dioxide storage tank. Balance, compress and condense a part of the carbon dioxide and circulate it back to the carbon dioxide storage tank, then perform pressure balance with the carbon dioxide recovery tank, and introduce the remaining part of the carbon dioxide into the carbon dioxide recovery tank, wherein the carbon dioxide in the carbon dioxide recovery tank can be used when the equipment is not in operation It is compressed and condensed and introduced into a carbon dioxide storage tank. And calculate the drying efficiency and energy consumption. Among them, the condition parameters in each device and the parameters of the drying process are listed in Table 1, and the results of drying efficiency and energy consumption are listed in Table 2.

Example 2-6

Embodiments 2-6 are carried out in a method similar to that of Examples, except that the condition parameters in the device and the parameters of the drying process are listed in Table 1, and the results are listed in Table 2.

Comparative example 1

This comparative example is carried out in a method similar to that of Example 1, except that the setting of the pipeline is adjusted so that the treated carbon dioxide is introduced from the bottom of the drying kettle and drawn from the top of the drying kettle. The specific drying conditions are shown in Table 1 , the results are shown in Table 2.

Comparative example 2

This comparative example is carried out in a method similar to that of Example 1, except that the connection mode of the drying kettle is adjusted so that the drying kettle is connected in series, and the carbon dioxide entering the next drying kettle is drawn from the previous drying kettle , the specific drying conditions are shown in Table 1, and the results are shown in Table 2.

Comparative example 3

This comparative example is carried out in a method similar to that of Example 1, except that the connection mode of the drying kettle is adjusted so that the drying kettle is connected in series, and the carbon dioxide entering the next drying kettle is drawn from the previous drying kettle , while adjusting the setting of the pipeline so that the treated carbon dioxide is introduced from the lower part of the drying kettle and drawn out from the upper part of the drying kettle. The specific drying conditions are shown in Table 1 and the results are shown in Table 2.

Drying efficiency: the weight of recovered solvent per unit time, unit kg/h.

Table 1

Continued Table 1

Table 2

the	干燥效率(kg/h)Drying efficiency (kg/h)	能耗(kw h)Energy consumption (kw h)
实施例1Example 1	302302	298298
实施例2Example 2	285285	312312
实施例3Example 3	298298	308308
实施例4Example 4	276276	319319
实施例5Example 5	268268	324324

实施例6Example 6	270270	328328
对比例1Comparative example 1	256256	342342
对比例2Comparative example 2	262262	347347
对比例3Comparative example 3	245245	332332

It can be seen from the results in Table 2 that the supercritical carbon dioxide drying device and drying method provided by the present invention have higher drying efficiency and lower energy consumption.

The preferred embodiments of the present invention have been described in detail above, however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the disclosed content of the present invention. All belong to the protection scope of the present invention.

Claims

A supercritical carbon dioxide drying device is characterized in that the device comprises:

A supercritical treatment unit, a drying unit and a separation unit connected in sequence through pipelines, the drying unit contains 3-12 drying kettles arranged in parallel;

The supercritical treatment unit is used to perform supercritical treatment on the condensed carbon dioxide to obtain treated carbon dioxide;

The drying unit is used to contact the treated carbon dioxide with the material to be dried for drying treatment to obtain effluent I;

The separation unit is used to separate the effluent I to obtain recyclable carbon dioxide and effluent II;

The arrangement of the pipelines in the drying unit enables the treated carbon dioxide to be introduced from the upper part of each of the drying tanks and drawn out from the lower part of each of the drying tanks.
The device according to claim 1, wherein the number of drying kettles arranged in parallel in the drying unit is 3;

Preferably, the supercritical treatment unit contains a booster pump and a heat exchanger 1 connected in sequence;

Preferably, the separation unit contains a heat exchanger II and a separation tank connected in sequence, and the heat exchanger II communicates with the drying tank;

Preferably, the number of the heat exchanger II is at least 2, and the number of the separation tank is at least 2.
The device according to claim 2, wherein the device further comprises a recovery unit I and a recovery unit II, the recovery unit I is arranged downstream of the separation unit and communicates with the separation tank, and the recovery unit II It is arranged downstream of the drying unit in parallel with the separation unit, the recovery unit I is used to recover the effluent II, and the recovery unit II is used to recover a part of the recyclable carbon dioxide.
The device according to any one of claims 1-3, wherein the device further comprises a storage unit arranged upstream of the supercritical treatment unit, the storage unit being capable of storing carbon dioxide.
The device according to claim 4, wherein the device further comprises a condensing unit I arranged between the storage unit and the supercritical processing unit, and the condensing unit I is used for condensing the of the carbon dioxide;

Preferably, the device further includes a condensing unit II disposed between the storage unit and the recovery unit II, the condensing unit II is used for condensing the remaining part of the recyclable carbon dioxide.
Application of the supercritical carbon dioxide drying device described in any one of claims 1-5 in preparing airgel.
A supercritical carbon dioxide drying method, characterized in that the method is carried out in the supercritical carbon dioxide drying device described in any one of claims 1-5, comprising:

(1) introducing condensed carbon dioxide into a supercritical treatment unit for supercritical treatment to obtain treated carbon dioxide;

(2) introducing the treated carbon dioxide into each drying tank arranged in parallel in the drying unit to contact with the material to be dried for drying treatment to obtain effluent I;

(3) The effluent I is introduced into a separation unit for separation to obtain carbon dioxide and effluent II which can be recycled.
The method according to claim 7, wherein, the method also includes, before performing the step (1), first introducing the carbon dioxide raw material in the storage unit into the condensation unit I for condensation treatment I, to obtain the condensation After the carbon dioxide;

Preferably, the method further includes, after performing the step (3), introducing the effluent II into the recovery unit I for recovery treatment, introducing a part of the recyclable carbon dioxide into the recovery unit II And the remaining part of the recyclable carbon dioxide is recycled to the condensation unit II for condensation treatment II, and the material obtained after the condensation treatment II is introduced into the storage unit.
The method according to claim 7 or 8, wherein, in step (2), the conditions of the drying treatment in each of the drying tanks are the same or different, each independently at least satisfying: control of the treated carbon dioxide The flow rate is 800-1500L/h.
The method according to claim 9, wherein the conditions of the drying treatment in each of the drying tanks independently at least meet:

When the drying treatment is carried out for 0-2h, the carbon dioxide flow rate after the treatment is controlled to be 1200-1500L/h;

When the drying treatment is carried out for 2-4 hours, the carbon dioxide flow rate after the treatment is controlled to be 1000-1200L/h;

When the drying treatment is carried out for 4-6 hours, the flow rate of carbon dioxide after the treatment is controlled to be 800-1000 L/h.