An apparatus and method for drying aerogels

Abstract

The application discloses an apparatus for aerogel drying, which comprises a carbon dioxide supply tank, a condenser, a carbon dioxide storage tank, a pressurizing pump, a drying kettle, a separation kettle and a recovery tank. The method comprises the following steps: step 1, placing an aerogel roll containing a solvent into the drying kettle; step 2, pumping liquid carbon dioxide into the drying kettle, and converting it into a supercritical fluid by increasing temperature and pressure, so as to dry the aerogel roll; in the initial stage of drying, the supercritical drying fluid is kept circulating in the drying kettle, then the inlet and outlet valves of the drying kettle are closed, static pressure is built up, the pressure building up is stopped when the conductivity of the supercritical drying fluid in the drying kettle is stable, the inlet and outlet valves of the drying kettle are opened, the second supercritical fluid circulation in the drying kettle is started, and the process is continued until no solvent drops out of the separation kettle; and step 3, releasing the pressure in the drying kettle to normal pressure, and taking out the dried aerogel roll from the drying kettle.

Description

Technical Field

[0001] This invention relates to the field of functional aerogel preparation technology, and more specifically to an apparatus and method for drying aerogels. Background Technology

[0002] Aerogels are nanomaterials with porous structures and large specific surface areas, synthesized from various polymeric precursors through sol-gel technology and specialized drying methods. A major challenge in preparing aerogels is removing the liquid solvent from the gel without damaging the existing nanoporous structure, thereby avoiding subsequent shrinkage and cracking of the drying gel.

[0003] Currently, the most common drying method is supercritical drying. This method avoids gas-liquid transition and surface tension in the gel pores, preventing pore collapse (i.e., macroscopic changes) during solvent removal. Thus, it maintains the high porosity and excellent properties of the wet gel in its dried form, without any liquid phase residue.

[0004] Therefore, the most critical aspect of existing supercritical drying processes is the efficient and complete removal of solvent to maintain the integrity of the silica aerogel network. If solvent remains within the pores of the aerogel, it will cause the silica network to shrink and collapse. Currently, existing technologies use excessively long drying times in aerogel production to ensure no residual liquid remains. However, excessively long drying times lead to a waste of resources (working time, energy, facilities, etc.) and severely impact production capacity.

[0005] Furthermore, existing drying processes are insufficient for drying aerogel rolls. Due to the thickness of aerogel rolls, supercritical fluid cannot fully penetrate from the roll ends into the core, resulting in incomplete drying, poor drying effect, and significant differences in performance between the core and roll ends. Current technological solutions involve adding perforated meshes such as Teflon during the drying process to guide the supercritical fluid flow. However, this method still has significant problems. These meshes are prone to shrinkage, damage, and corrosion in acidic or alkaline environments, with a lifespan of only 1-2 months. This necessitates frequent mesh replacements in industrial production, increasing drying costs, significantly increasing the workload of operators, and leading to decreased production efficiency and resource waste. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide an apparatus and method for drying aerogels, so as to solve the problems of long supercritical drying time, frequent screen replacement, increased drying cost, increased workload of workers and decreased production efficiency in the prior art.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] An apparatus for drying aerogels, the apparatus comprising:

[0009] Carbon dioxide supply tank;

[0010] A condenser connected to a carbon dioxide supply tank pipeline;

[0011] A carbon dioxide storage tank that is fluidly connected to a carbon dioxide supply tank via a condenser;

[0012] A booster pump connected to the carbon dioxide storage tank pipeline;

[0013] At least one drying vessel is fluidly connected to a carbon dioxide storage tank via a pressurizing pump;

[0014] At least one separation vessel is fluidly connected to the drying vessel;

[0015] The recovery tank is fluidly connected to the separation vessel;

[0016] The top of the drying vessel is fluidly connected to the carbon dioxide storage tank via an upper feed pipe and a preheater, and its bottom is fluidly connected to the separation vessel via a lower discharge pipe; the bottom of the drying vessel is fluidly connected to the carbon dioxide storage tank via a lower feed pipe and a preheater, and the feed end of the lower feed pipe extends into and is located at the center of the aerogel roll inside the drying vessel.

[0017] The drying vessel is equipped with a conductivity meter to detect the conductivity of the supercritical carbon dioxide fluid inside the drying vessel.

[0018] Preferably, when there are two or more separation vessels, the multiple separation vessels are connected in series between the drying vessel and the recovery tank.

[0019] Preferably, when there are two or more drying vessels, the drying vessels are fluidly connected between the carbon dioxide storage tank and the separation vessel in series and / or parallel.

[0020] Preferably, the temperature inside the carbon dioxide storage tank is 5–18°C and the pressure is 5–6 MPa.

[0021] Preferably, the temperature inside the drying vessel and / or separation vessel is 35°C to 55°C, and the working pressure is 3 to 5 MPa.

[0022] This invention provides a method for drying aerogels, the method employing the above-mentioned apparatus, and specifically includes the following steps:

[0023] Step 1: Place the aerogel roll containing the solvent into a drying oven;

[0024] Step 2: Pump liquid carbon dioxide into the drying kettle, heat and pressurize it to convert it into a supercritical fluid, and then dry the aerogel roll material; in the initial stage of drying, keep the supercritical drying fluid circulating in the drying kettle, then close the inlet and outlet valves of the drying kettle and allow it to stand still and pressurize. After the conductivity of the supercritical drying fluid in the drying kettle stabilizes, stop pressurizing, open the inlet and outlet valves of the drying kettle, and start the second circulation of the supercritical fluid in the drying kettle until no solvent drips out of the separation kettle;

[0025] Step 3: Depressurize the drying autoclave to atmospheric pressure and remove the dried aerogel roll from the autoclave.

[0026] Preferably, in step 1, the bottom of the drying vessel is provided with a lower feed pipe, so that the feed end of the lower feed pipe extends into the center of the aerogel roll.

[0027] Preferably, in step 2, carbon dioxide is liquefied into a carbon dioxide gas-liquid mixture by a condenser under low temperature and pressure conditions, and then pressurized to 8-17 MPa by a pressurizing pump before being sent into a drying kettle.

[0028] Preferably, in step 2, the carbon dioxide gas-liquid mixture is heated to 35–55°C before entering the drying vessel.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The method described in this invention employs a combination of circulation, static pressure holding, and circulation, allowing supercritical carbon dioxide fluid sufficient time to penetrate into the core of the roll material and extract the solvent from the core. Simultaneously, the change in conductivity is used to determine whether the solvent has been completely extracted during the static pressure holding period. Furthermore, the optimal static pressure holding time can be selected based on this method for roll materials of different thicknesses to ensure that the solvent is fully extracted.

[0031] 2. The device described in this invention modifies the existing drying kettle by setting up two pipes for carbon dioxide liquid to enter the drying kettle. One pipe enters from the top of the drying kettle, allowing the carbon dioxide liquid to penetrate from the outside into the interior of the aerogel roll, and the other pipe enters from the bottom of the drying kettle, allowing the carbon dioxide liquid to penetrate from the inside of the aerogel roll outward. The two processes are carried out simultaneously, which can achieve thorough drying of the roll, avoid the use of the flow guide mesh, and significantly reduce production costs. At the same time, it can greatly reduce the extraction time and improve production efficiency and output. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of an apparatus for drying aerogel according to the present invention.

[0033] In the diagram: 1. Carbon dioxide supply tank; 2. Condenser; 3. Carbon dioxide storage tank; 5. Drying kettle; 6. Separation kettle; 4. Preheater; 7. Conductivity meter; 8. Inlet valve; 9. Outlet valve. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the present invention are within the scope of protection of the present invention.

[0035] Unless otherwise specified in the specific context, the numerical ranges listed herein include upper and lower limits, as well as all integers and fractions within that range, but are not limited to the specific values ​​listed when the range is defined. The term "and / or" as used herein is inclusive; for example, "A and / or B" means either only A, or only B, or both A and B.

[0036] I. An apparatus for drying aerogels

[0037] The device described in this invention is as follows Figure 1 As shown, the device includes:

[0038] Carbon dioxide gas supply tank 1;

[0039] Condenser 2 is connected to the carbon dioxide supply tank pipeline;

[0040] Carbon dioxide storage tank 3 is fluidly connected to the carbon dioxide supply tank via a condenser;

[0041] A booster pump connected to the carbon dioxide storage tank pipeline;

[0042] At least one drying vessel 5 is fluidly connected to a carbon dioxide storage tank via a pressurizing pump;

[0043] At least one separation vessel 6 is fluidly connected to the drying vessel;

[0044] The recovery tank is fluidly connected to the separation vessel;

[0045] The top of the drying kettle is fluidly connected to the carbon dioxide storage tank via the preheater 4 through the upper feed pipe, and its bottom is fluidly connected to the separation kettle via the lower discharge pipe; the bottom of the drying kettle is fluidly connected to the carbon dioxide storage tank via the preheater through the lower feed pipe, and the feed end of the lower feed pipe extends into and is located at the center of the aerogel roll inside the drying kettle.

[0046] The drying vessel is equipped with a conductivity meter 7, which is used to detect the conductivity of the supercritical carbon dioxide fluid inside the drying vessel.

[0047] This invention improves upon existing drying reactors by first incorporating two carbon dioxide liquid inlet pipes: an upper inlet pipe and a lower inlet pipe. The upper inlet pipe allows the carbon dioxide liquid to permeate from the outside of the aerogel roll material to the inside, while the lower inlet pipe allows it to permeate from the inside to the outside. These two permeation processes occur simultaneously, shortening the drying time of the roll material, eliminating the need for a flow guide mesh, and also reducing extraction time, thus improving production efficiency. Furthermore, this invention includes a conductivity meter within the drying reactor to detect the conductivity of the supercritical carbon dioxide fluid. Since supercritical carbon dioxide itself is not conductive, it becomes conductive after solvent extraction, and its conductivity increases with the amount of extracted solvent. Therefore, this invention determines whether the solvent has been completely extracted during the static pressure-holding period by observing changes in conductivity. When the conductivity reaches a stable level, the solvent can be considered completely extracted. Thus, the device described in this invention is universally applicable for drying roll materials of different thicknesses.

[0048] In some embodiments, the bottom of the drying reactor is equipped with a lower feed pipe, the feed end of which extends into the center of the aerogel roll. Liquid carbon dioxide can directly enter the core of the aerogel roll through the lower feed pipe, thus expanding outwards from the core to the surface of the roll. Specifically, the feed end of the lower feed pipe extends into the core of the roll from its axial position, ensuring that the lower feed pipe does not damage the aerogel roll during insertion. In this way, within the drying reactor, liquid carbon dioxide can simultaneously penetrate from both the inside and outside of the aerogel roll, ensuring that all solvents contained in the roll are completely extracted.

[0049] In some embodiments, when there are two or more separation vessels, they are connected in series between the drying vessel and the recovery tank. The number of separation vessels does not affect the technical effect of the solution described in this invention, and a reasonable number of separation vessels can be designed according to the size of the aerogel roll.

[0050] In some embodiments, when there are two or more drying kettles, the drying kettles are fluidly connected between the carbon dioxide storage tank and the separation kettle in series and / or parallel. When there is a large quantity of aerogel rolls to be dried, multiple drying kettles can be pre-designed on the same production line for simultaneous drying. These multiple drying kettles can be initially connected in parallel and then fluidly connected to the carbon dioxide storage tank and the separation kettle, or they can be fluidly connected in series. One drying kettle can be connected in series or parallel with multiple separation kettles simultaneously, and multiple drying kettles can also be connected in series or parallel with one separation kettle simultaneously.

[0051] In some embodiments, the temperature inside the carbon dioxide storage tank is 5–18°C, and the pressure is 5–6 MPa. The carbon dioxide supply tank introduces gaseous carbon dioxide into the condenser, where it is liquefied into a carbon dioxide gas-liquid mixture by the condenser and a pressurizing pump, and then transported to the carbon dioxide storage tank. The temperature inside the carbon dioxide storage tank is controlled at 5–18°C, and the pressure is controlled at 5–6 MPa to ensure the stability of the carbon dioxide gas-liquid mixture within the tank.

[0052] In some embodiments, the temperature of the drying vessel and / or separation vessel is 35–55°C, and the working pressure is 3–5 MPa. If the temperature inside the drying vessel is too low, carbon dioxide cannot maintain a supercritical state, thus affecting the extraction effect on the solvent within the roll material; however, if the temperature inside the drying vessel is too high, the solvent will evaporate rapidly, causing damage to the aerogel structure. This results in excessively large performance differences between the core, ends, and surface of the aerogel roll material, ultimately adversely affecting the overall performance of the aerogel roll material.

[0053] II. A method for drying aerogels

[0054] Step 1: Place the aerogel roll containing the solvent into a drying oven;

[0055] Step 2: Pump liquid carbon dioxide into the drying kettle, heat and pressurize it to convert it into a supercritical fluid, and then dry the aerogel roll material; in the initial stage of drying, keep the supercritical drying fluid circulating in the drying kettle, then close the inlet and outlet valves of the drying kettle and allow it to stand still and pressurize. After the conductivity of the supercritical drying fluid in the drying kettle stabilizes, stop pressurizing, open the inlet and outlet valves of the drying kettle, and start the second circulation of the supercritical fluid in the drying kettle until no solvent drips out of the separation kettle;

[0056] Step 3: Depressurize the drying autoclave to atmospheric pressure and remove the dried aerogel roll from the autoclave.

[0057] In existing technologies, traditional drying methods involve continuously circulating carbon dioxide in a supercritical fluid state throughout the drying process (from the start to the end of drying). A problem with this method is that the supercritical fluid only removes solvent from the ends and / or surface of the aerogel roll during circulation, failing to extract solvent from the core, which takes an extremely long time. This not only results in a very long drying time for the aerogel roll, wasting time, but also leads to significant performance differences between the core and the ends. Therefore, the primary consideration of this invention is how to improve the fluid's permeability to extract solvent from the aerogel core in a short time, while simultaneously avoiding significant performance differences between the core and the ends.

[0058] In actual production, this invention reveals that carbon dioxide, after passing through a condenser, preheater, and pressurization pump from the gas supply tank, enters the drying kettle in a gas-liquid mixture state. Within the drying kettle, it undergoes further heating and pressurization, transforming into a supercritical fluid. After drying the aerogel roll material, the supercritical fluid, upon depressurization, returns to a gas-liquid mixture state. Therefore, during the drying process, the carbon dioxide within the drying kettle circulates in a cycle of gas-liquid mixture → supercritical fluid → gas-liquid mixture → supercritical fluid. During this process, the drying kettle is sealed for static pressure buildup. Static pressure buildup refers to closing all material inlets and outlets of the drying kettle. Since the pressure inside the kettle is provided by the pumped carbon dioxide, the pressure and temperature remain constant after closing all material inlets and outlets, extending the residence time of the fluid within the drying kettle. This allows the supercritical fluid sufficient time to permeate the aerogel roll material, resulting in deeper extraction. More importantly, the drying method described in this invention achieves better drying results, maximizing the preservation of the aerogel network structure without damage, and further improving product performance, resulting in a higher specific surface area for both the core and ends of the roll material. Meanwhile, the method described in this invention avoids the use of flow guide mesh in traditional drying methods, because the use of flow guide mesh occupies space inside the drying kettle, resulting in wasted space. The method described in this invention fundamentally solves this technical problem. Not using flow guide mesh can not only save production costs, but also improve production efficiency.

[0059] In specific implementation, in step 1, a lower feed pipe is provided at the bottom of the drying kettle, with the feed end of the lower feed pipe extending into the core of the aerogel roll. Carbon dioxide liquid can directly enter the core of the aerogel roll through the lower feed pipe, thus expanding outwards from the core to the surface of the roll. Specifically, the feed end of the lower feed pipe extends into the core of the roll from the axial position, ensuring that the lower feed pipe does not damage the aerogel roll. In this way, within the drying kettle, carbon dioxide liquid can simultaneously penetrate from both the inside and outside of the aerogel roll, ensuring that all solvents contained in the roll are completely extracted.

[0060] In some embodiments, carbon dioxide is liquefied into a carbon dioxide gas-liquid mixture by a condenser under low temperature and pressure conditions, and then pressurized to 8-17 MPa by a pressurizing pump before being sent into a drying kettle.

[0061] In some embodiments, in step 2, the carbon dioxide gas-liquid mixture is heated to 35–55°C before entering the drying vessel.

[0062] III. Examples and Comparative Examples

[0063] For wet gels prepared with the same ratio, the theoretical density is the same. However, during supercritical drying, the smaller the shrinkage rate and the smaller the bulk density, the more uniform the aerogel structure distribution and the lower the thermal conductivity. In addition, after supercritical drying, a larger specific surface area can indirectly indicate that there are more pore structures and the sample particles are closer to the nanoscale. Therefore, specific surface area, thermal conductivity and density are selected as indicators to evaluate the performance of the samples. The test methods are strictly carried out in accordance with the national standard GB / T34336-2017 for nanoporous aerogel composite thermal insulation products.

[0064] Example 1

[0065] Step 1: Place the aerogel roll containing solvent and without a separator in a drying oven;

[0066] Step 2: Pump liquid carbon dioxide into the drying vessel, heat and pressurize it to convert it into a supercritical fluid, which takes 1 hour. At this time, the temperature inside the drying vessel is 50℃ and the pressure is 14 MPa. During the first 2 hours of drying, keep the supercritical drying fluid circulating in the drying vessel. Then close the inlet and outlet valves of the drying vessel and allow it to stand still for 4 hours. After that, open the inlet and outlet valves of the drying vessel and start the second circulation of the supercritical fluid in the drying vessel for 2 hours until no solvent drips out of the separation vessel.

[0067] Step 3: Depressurize the drying kettle to atmospheric pressure, which takes 1 hour. Remove the dried aerogel roll from the drying kettle. The total time is 10 hours.

[0068] Comparative Example 1: Compared with Example 1, Comparative Example 1 did not undergo static pressure buildup.

[0069] Step 1: Place the aerogel roll containing solvent and without a separator in a drying oven;

[0070] Step 2: Pump liquid carbon dioxide into the drying vessel, heat and pressurize it to convert it into a supercritical fluid, which takes 1 hour. At this time, the temperature inside the drying vessel is 50℃ and the pressure is 14 MPa. Then keep the inlet and outlet valves fully open and continue to circulate for 8 hours.

[0071] Step 3: Depressurize the drying kettle to atmospheric pressure, which takes 1 hour. Remove the dried aerogel roll from the drying kettle. The total time is 10 hours.

[0072] Table 1 shows the test results of dried aerogel rolls with a radius and thickness of 25 cm in Example 1 and Comparative Example 1. All test samples were taken from the core and 1 m from the end of the aerogel roll, and no flow-guiding mesh was added to either sample.

[0073] Table 1. Test results of Example 1 and Comparative Example 1

[0074]

[0075] A comparison of the three test results between Example 1 and Comparative Example 1 shows that, under the same drying parameters, the performance of the aerogel roll core and roll ends obtained using the method and apparatus described in this invention is not significantly different, proving that the core and roll ends are completely dried. However, in Comparative Example 1, because the aerogel roll was not subjected to static pressure during the drying process, only part of the solvent at the roll ends was extracted during fluid circulation, while the solvent at the core was not extracted. This resulted in a very significant difference in the performance of the dried aerogel roll core and roll ends.

[0076] Example 2

[0077] The steps in Example 2 are the same as in Example 1, except that a new, undried aerogel roll with the same specifications as in Example 1 is used for drying.

[0078] Comparative Example 2

[0079] Comparative Example 2, based on Comparative Example 1, adds a flow-guiding mesh inside the aerogel roll to compare the differences between the new drying process and the existing drying process; all other parameters remain unchanged.

[0080] Table 2 shows the test results of the aerogel roll with a radius and thickness of 25 cm after drying in Example 2 and Comparative Example 2. The test samples were all taken from the core and 1 m from the end of the aerogel roll. No flow guide net was added in Example 2, while a flow guide net was added in Comparative Example 2.

[0081] Table 2 Test results of Example 2 and Comparative Example 2

[0082]

[0083] Combining Tables 1 and 2, the performance of the core of Comparative Example 2 was improved compared to Comparative Example 1 after adding the flow-guiding mesh, indicating that the flow-guiding mesh does indeed improve the drying effect. However, this drying effect is still not good; the density of the core and roll ends of Comparative Example 2 is still relatively high, indicating that the roll material of Comparative Example 2 is not completely dry and still contains some solvent. Compared with Example 2, the drying effect of Comparative Example 2 is worse. Example 2 not only has similar density and thermal conductivity between the core and roll ends, but also has a significantly better specific surface area than Comparative Example 2. This shows that even if the existing technology improves the traditional drying process by adding a flow-guiding mesh, the performance of the aerogel roll core obtained is still inferior to that of the embodiments of the present invention.

[0084] Example 3

[0085] Based on Examples 1 and 2, adjustments were made. The difference is that in Example 3, a conductivity meter was added to measure the optimal static pressure time. Ultimately, a static pressure time of 1 hour was adopted, and the total drying time was 7 hours.

[0086] Comparative Example 3

[0087] The steps for Comparative Example 3 are the same as those for Comparative Example 2.

[0088] Table 3 shows the test results of two drying methods on aerogel rolls with a radius and thickness of 25cm after drying. The test samples were all taken from the core and 1m end of the aerogel roll. In Example 3, no flow guide net was added, while in Comparative Example 3, a flow guide net was added.

[0089] Table 3 Test results of Example 3 and Comparative Example 3

[0090]

[0091] A comparison of the three test results in Example 3 and Comparative Example 3 shows that the optimal drying time (7h) was accurately obtained based on the conductivity meter results. Furthermore, the performance of the dried roll material is not significantly different from the products obtained in Examples 1 and 2 using a 10h drying time. This demonstrates that the method and apparatus described in this invention can significantly shorten the drying time while maintaining material properties. Simultaneously, Examples 1-3 also demonstrate the feasibility of using a conductivity meter to measure the optimal static pressure-holding time, which can significantly shorten the drying time, increase production, and improve profits while maintaining material properties.

[0092] Example 4

[0093] Based on Examples 1, 2, and 3, adjustments were made. The difference is that Example 4 used an aerogel roll with a radius and thickness of 30cm without a spacer to compare the drying effect of the drying process described in this invention on rolls of different sizes. A conductivity meter was also added to measure the optimal static pressure time. Finally, a static pressure time of 1.5h was adopted, and the total drying time was 7.5h.

[0094] Comparative Example 3

[0095] Comparative Example 4 was adjusted based on Comparative Example 3. The difference is that Comparative Example 4 used an aerogel roll material with a radius and thickness of 30 cm and an added mesh.

[0096] Table 4 shows the test results of two drying methods on aerogel rolls with a radius and thickness of 30 cm after drying. The test samples were all taken from the core and 1 m from the end of the aerogel roll. In Example 4, no flow guide net was added, while in Comparative Example 4, a flow guide net was added.

[0097] Table 4. Test results of Example 4 and Comparative Example 4

[0098]

[0099] Example 4 and Comparative Example 4 used thicker rolls of material. A comparison of the three test results shows that the drying process in Example 4 accurately determined the optimal drying time (7.5h) based on the conductivity meter results, and the performance of the dried rolls was not significantly different from the products obtained in Examples 1, 2, and 3 using the same drying method. Conversely, Comparative Example 4, which used a conventional drying process, maintained a 10h drying time due to the inability to accurately determine the drying time when the roll size changed. This resulted in solvent residue on both the core and ends of the roll, leading to a significant increase in thermal conductivity and a substantial decrease in product performance.

[0100] In summary, repeated experiments of Comparative Examples 1, 2, 3, and 4 and Examples 1, 2, 3, and 4 have confirmed the reliability of the drying method described in this invention and the accuracy of using a conductivity meter to determine the drying time when dealing with aerogel rolls of different sizes.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. An apparatus for drying aerogels, characterized in that, The device includes: Carbon dioxide gas supply tank (1); Condenser (2) connected to carbon dioxide supply tank pipeline; A carbon dioxide storage tank (3) is fluidly connected to a carbon dioxide supply tank via a condenser. A booster pump connected to the carbon dioxide storage tank pipeline; At least one drying vessel (5) is fluidly connected to a carbon dioxide storage tank via a pressurizing pump; At least one separation vessel (6) is fluidly connected to the drying vessel; The recovery tank is fluidly connected to the separation vessel; The top of the drying kettle is fluidly connected to the carbon dioxide storage tank via the upper feed pipe and the preheater (4), and its bottom is fluidly connected to the separation kettle via the lower discharge pipe; the bottom of the drying kettle is fluidly connected to the carbon dioxide storage tank via the lower feed pipe and the preheater, and the feed end of the lower feed pipe extends into and is located at the center of the aerogel roll inside the drying kettle. The drying vessel is equipped with a conductivity meter (7) to detect the conductivity of the supercritical carbon dioxide fluid inside the drying vessel.

2. The apparatus according to claim 1, characterized in that, When there are two or more separation vessels, multiple separation vessels are connected in series between the drying vessel and the recovery tank.

3. The apparatus according to claim 1, characterized in that, When there are two or more drying vessels, the drying vessels are fluidly connected between the carbon dioxide storage tank and the separation vessel in series and / or parallel.

4. The apparatus for drying aerogels according to claim 1, characterized in that, The temperature inside the carbon dioxide storage tank is 5~18℃, and the pressure is 5~6MPa.

5. The apparatus for drying aerogels according to claim 1, characterized in that, The temperature inside the drying vessel and / or separation vessel is 35℃~55℃, and the working pressure is 3~5MPa.

6. A method for drying aerogels, characterized in that, The method employs the apparatus described in any one of claims 1 to 5, and specifically includes the following steps: Step 1: Place the aerogel roll containing the solvent into a drying oven; Step 2: Pump liquid carbon dioxide into the drying kettle, heat and pressurize it to convert it into a supercritical fluid, and then dry the aerogel roll material; in the initial stage of drying, keep the supercritical drying fluid circulating in the drying kettle, then close the inlet and outlet valves of the drying kettle and allow it to stand still and pressurize. After the conductivity of the supercritical drying fluid in the drying kettle stabilizes, stop pressurizing, open the inlet and outlet valves of the drying kettle, and start the second circulation of the supercritical fluid in the drying kettle until no solvent drips out of the separation kettle; Step 3: Depressurize the drying autoclave to atmospheric pressure and remove the dried aerogel roll from the autoclave.

7. The method according to claim 6, characterized in that, In step 1, a lower feed pipe is provided at the bottom of the drying kettle, so that the feed end of the lower feed pipe extends into the center of the aerogel roll.

8. The method according to claim 6, characterized in that, In step 2, carbon dioxide is liquefied into a carbon dioxide gas-liquid mixture by a condenser under low temperature and pressure conditions, and then pressurized to 8~17MPa by a pressurizing pump before being sent into a drying kettle.

9. The method according to claim 6, characterized in that, In step 2, the carbon dioxide gas-liquid mixture is heated to 35~55°C before entering the drying vessel.

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