CN116929005B - Normal-pressure drying method and system for silicon-based aerogel - Google Patents

Abstract

The invention relates to the technical field of drying control, and particularly provides a normal pressure drying method and system for silicon-based aerogel, wherein the method comprises the following steps: sealing the sol to be dried, heating in water bath, and collecting the mass and real-time temperature of the sol to be dried; determining the stirring time and the initial stirring rate during heating in a water bath, and adjusting the initial stirring rate according to the real-time temperature to obtain aerogel to be dried; collecting viscosity data of aerogel to be dried, and judging whether water bath heating is qualified or not; when the water bath heating is judged to be qualified, putting the aerogel to be dried into a sheet-shaped mold, and placing the sheet-shaped mold in a drying chamber for normal-pressure drying; during normal pressure drying, determining the initial rotating speed of a drying fan according to the arrangement density; and acquiring real-time quality data of aerogel to be dried, and judging whether to adjust the initial rotating speed. The method realizes the intelligent control of normal-pressure drying, and improves the preparation quality and stability of the aerogel.

Description

Normal-pressure drying method and system for silicon-based aerogel

Technical Field

The invention relates to the technical field of drying control, in particular to a normal pressure drying method and system for silicon-based aerogel.

Background

Silica-based aerogel is a porous, lightweight, highly porous solid material with a specific microstructure that makes it widely applicable in the fields of adsorption, thermal insulation, sound absorption, insulation, etc. It is formed of three-dimensional network silicon oxide or silicon-containing compound, has extremely high specific surface area and porosity, resulting in excellent adsorption and separation properties.

The drying step is very important in the production of silica-based aerogels, which directly affects the final properties and quality of the aerogel. The main purpose of the drying step is to remove the liquid portion of the gel, allowing the aerogel to retain its porous structure and pore properties. However, the supercritical drying method generally adopted in the current drying has high equipment cost and higher operation technical requirements; the normal pressure drying method has low cost, and the drying effect is often influenced by the experience of workers in the normal pressure drying process, which may cause the problems of uneven shrinkage, deformation, cracking and the like of the aerogel in the drying process. This not only limits the quality of the aerogel preparation, but also increases the uncertainty in the production process.

Therefore, it is necessary to design an atmospheric drying method and system for silica-based aerogel to solve the problems existing in the current atmospheric drying of silica-based aerogel.

Disclosure of Invention

In view of the above, the invention provides a normal pressure drying method and system for silicon-based aerogel, which aim to solve the problem of lower reliability and stability in the current normal pressure drying of silicon-based aerogel.

In one aspect, the invention provides an atmospheric drying method for silica-based aerogel, comprising:

sealing the sol to be dried, heating in water bath, and collecting the mass and real-time temperature of the sol to be dried;

determining the stirring time and the initial stirring rate when the sol to be dried is heated in a water bath according to the mass of the sol to be dried, adjusting the initial stirring rate according to the real-time temperature, and completing the gel stirring at the adjusted stirring rate to obtain aerogel to be dried;

collecting viscosity data of the aerogel to be dried, and judging whether water bath heating is qualified or not according to the viscosity data;

after the water bath heating is judged to be qualified, loading the aerogel to be dried into a flaky mould, and then placing the flaky mould into a drying chamber for normal pressure drying; when normal-pressure drying is carried out, determining the initial rotating speed of a drying fan according to the arrangement density of the flaky mould;

collecting real-time quality data of the aerogel to be dried, and judging whether to adjust the initial rotating speed according to the real-time quality data;

And when the initial rotating speed is judged not to be adjusted, stopping the drying fan if the real-time quality data does not change within the preset time.

Further, determining the stirring time and the initial stirring rate during water bath heating according to the mass of the sol to be dried, including:

presetting a first preset mass M1, a second preset mass M2 and a third preset mass M3, wherein M1 is more than M2 and less than M3; presetting a first preset stirring time T1, a second preset stirring time T2 and a third preset stirring time T3, wherein T1 is more than T2 and less than T3; presetting a first preset stirring rate Vj1, a second preset stirring rate Vj2 and a third preset stirring rate Vj3, wherein Vj1 is less than Vj2 and less than Vj3;

determining the stirring time and the initial stirring rate when the water bath is heated according to the size relation between the mass M of the sol to be dried and each preset mass;

when M1 is less than or equal to M2, determining the stirring time during heating in the water bath as T1, and determining the initial stirring rate as Vj1;

when M2 is less than or equal to M3, determining the stirring time to be T2 during heating in the water bath, and determining the initial stirring rate to be Vj2;

and when M3 is less than or equal to M, determining the stirring time during heating the water bath to be T3, and determining the initial stirring rate to be Vj3.

Further, when the stirring time during heating in the water bath is determined to be Ti, after the initial stirring rate is Vji, i=1, 2,3, the initial stirring rate is adjusted according to the real-time temperature, and the gel is stirred at the adjusted stirring rate, so as to obtain the aerogel to be dried, which comprises:

presetting a first preset temperature W1, a second preset temperature W2 and a third preset temperature W3, wherein W1 is more than W2 and less than W3; presetting a first preset rate adjustment coefficient A1, a second preset rate adjustment coefficient A2 and a third preset rate adjustment coefficient A3, wherein A1 is more than A2 and less than A3;

according to the relation between the real-time temperature W and each preset temperature, selecting a speed adjusting coefficient to adjust the initial stirring speed Vji, and obtaining an adjusted stirring speed;

when W1 is less than or equal to W2, selecting the third preset rate adjustment coefficient A3 to adjust the initial stirring rate Vji, and obtaining an adjusted stirring rate Vji x A3;

when W2 is less than or equal to W3, selecting the second preset rate adjustment coefficient A2 to adjust the initial stirring rate Vji, and obtaining an adjusted stirring rate Vji;

when W3 is less than or equal to W, selecting the first preset rate adjustment coefficient A1 to adjust the initial stirring rate Vji, and obtaining an adjusted stirring rate Vji ×a1.

Further, after selecting the i-th preset rate adjustment coefficient Ai to adjust the initial stirring rate Vji and obtaining the adjusted stirring rate Vji ×ai, i=1, 2,3, collecting viscosity data of the aerogel to be dried, and judging whether water bath heating is qualified according to the viscosity data, including:

presetting a viscosity threshold Nmax, and judging whether water bath heating is qualified or not according to the relationship between the viscosity data N of the aerogel to be dried and the viscosity threshold Nmax;

when N is more than or equal to Nmax, judging that the water bath is qualified in heating, and performing normal-pressure drying on the aerogel to be dried;

and when N is less than Nmax, judging that the water bath heating is unqualified, and performing secondary water bath heating on the aerogel to be dried.

Further, when it is determined that the water bath heating is not qualified, and the aerogel to be dried is subjected to secondary water bath heating, the method includes:

acquiring a viscosity difference delta N=Nmax-N between the viscosity data N and a viscosity threshold value Nmax, and presetting a first preset viscosity difference delta N1, a second preset viscosity difference delta N2 and a third preset viscosity difference delta N3, wherein delta N1 is less than delta N2;

determining the stirring time during the heating of the secondary water bath according to the relationship between the viscosity difference delta N and each preset viscosity difference;

Presetting a first preset secondary stirring time R1, a second preset secondary stirring time R2 and a third preset secondary stirring time R3, wherein R1 is more than R2 and less than R3;

when delta N1 is less than or equal to delta N < [ delta ] N2, determining the stirring time during the secondary water bath heating to be R1;

when delta N2 is less than or equal to delta N < [ delta ] N3, determining the stirring time during the secondary water bath heating to be R2;

when delta N3 is less than or equal to delta N, determining the stirring time during the heating in the secondary water bath as R3.

Further, when it is judged that the water bath heating is qualified and then normal-pressure drying is performed, determining an initial rotation speed of the drying fan according to the arrangement density of the sheet-shaped mold, including:

presetting a first preset rotating speed Z1, a second preset rotating speed Z2 and a third preset rotating speed Z3, wherein Z1 is more than Z2 and less than Z3; presetting a first preset arrangement density P1, a second preset arrangement density P2 and a third preset arrangement density P3, wherein P1 is more than P2 and less than P3;

determining the initial rotating speed of the drying fan according to the relation between the arrangement density P0 of the lamellar mould and each preset arrangement density;

when P1 is less than or equal to P0 and less than P2, determining the initial rotating speed of the drying fan as Z3;

when P2 is less than or equal to P0 and less than P3, determining the initial rotating speed of the drying fan as Z2;

and when P3 is less than or equal to P0, determining the initial rotating speed of the drying fan to be Z1.

Further, after selecting the i-th preset rotation speed Zi as the initial rotation speed, i=1, 2,3, collecting real-time quality data of the aerogel to be dried, and determining whether to adjust the initial rotation speed according to the real-time quality data, including:

acquiring a quality data change rate L0 according to real-time quality data, presetting a quality data change rate threshold Lmax, and judging whether to adjust the initial rotating speed according to the magnitude relation between the quality data change rate L0 and the quality data change rate threshold Lmax;

when L0 is more than or equal to Lmax, judging that the initial rotation speed needs to be adjusted;

when L0 < Lmax, it is determined that no adjustment is required for the initial rotation speed.

Further, when it is determined that the initial rotation speed needs to be adjusted, the method includes:

presetting a first preset mass change rate L1, a second preset mass change rate L2 and a third preset mass change rate L3, wherein L1 is more than L2 and less than L3; presetting a first preset rotating speed adjusting coefficient C1, a second preset rotating speed adjusting coefficient C2 and a third preset rotating speed adjusting coefficient C3, wherein C1 is more than C2 and less than C3;

according to the magnitude relation between the quality data change rate L0 and each preset quality change rate, selecting a rotation speed adjustment coefficient to adjust the initial rotation speed Zi, and obtaining an adjusted rotation speed;

When L1 is less than or equal to L0 and less than L2, selecting a third preset rotating speed adjustment coefficient C3 to adjust the initial rotating speed Zi, and obtaining an adjusted rotating speed Zi×C3;

when L2 is less than or equal to L0 and less than L3, selecting a second preset rotating speed adjustment coefficient C2 to adjust the initial rotating speed Zi, and obtaining an adjusted rotating speed Zi×C2;

when L3 is less than or equal to L0, a first preset rotating speed adjusting coefficient C1 is selected to adjust the initial rotating speed Zi, and the adjusted rotating speed Zi is obtained.

Further, after selecting the i-th preset rotation speed adjustment coefficient Ci to adjust the initial rotation speed Zi and obtaining the adjusted rotation speed Zi, i=1, 2,3, and adjusting the initial rotation speed, the method further includes:

acquiring a real-time air flow rate K0 around the lamellar mould, and presetting a first preset flow rate K1, a second preset flow rate K2 and a third preset flow rate K3, wherein K1 is smaller than K2 and smaller than K3; according to the relation between the real-time air flow velocity K0 and each preset flow velocity, selecting a rotation speed adjustment coefficient to secondarily adjust the adjusted rotation speed Zi, and finishing normal-pressure drying at the secondarily adjusted rotation speed;

when K1 is less than or equal to K0 and less than K2, selecting the third preset rotating speed adjusting coefficient C3 to carry out secondary adjustment on the adjusted rotating speed Zi, and obtaining the rotating speed Zi, ci and C3 after secondary adjustment;

When K2 is less than or equal to K0 and less than K3, selecting the second preset rotating speed adjusting coefficient C2 to carry out secondary adjustment on the adjusted rotating speed Zi, and obtaining the rotating speed Zi, ci and C2 after secondary adjustment;

when K3 is less than or equal to K0, selecting the first preset rotation speed adjustment coefficient C1, and performing secondary adjustment on the adjusted rotation speed zi×ci to obtain a rotation speed zi×ci×c1 after secondary adjustment.

Compared with the prior art, the invention has the beneficial effects that: the stirring time and the initial stirring rate during heating the water bath are determined according to the mass of the sol to be dried, and the initial stirring rate is adjusted according to the real-time temperature so as to achieve the optimal stirring effect. The aerogel is ensured to be fully and uniformly distributed in the stirring process, and the problems of shrinkage, deformation and the like of the aerogel are reduced, so that the consistency and quality of preparation are improved. By collecting viscosity data of the aerogel to be dried and judging whether water bath heating is qualified or not, the method effectively evaluates the progress of the gel process, and avoids stopping the gel too early or too late, thereby further ensuring the quality and performance of the aerogel. The aerogel to be dried is put into a flake-form mold, and then is dried under normal pressure. The intelligent control of the drying process is realized by determining the initial rotation speed of the drying fan according to the arrangement density of the lamellar mould. The stability and consistency of the drying process are further ensured by collecting the real-time quality data and judging whether to adjust the initial rotating speed according to the real-time quality data.

In another aspect, the present invention also provides an atmospheric drying system for silica-based aerogel, comprising:

the water bath heating unit is configured to perform water bath heating after sealing the sol to be dried, and collect the mass and the real-time temperature of the sol to be dried;

the stirring adjustment unit is configured to determine the stirring time and the initial stirring rate when the sol to be dried is heated in a water bath according to the mass of the sol to be dried, adjust the initial stirring rate according to the real-time temperature, and complete the gel stirring at the adjusted stirring rate to obtain the aerogel to be dried;

the judging unit is configured to collect viscosity data of the aerogel to be dried and judge whether water bath heating is qualified or not according to the viscosity data;

an atmospheric pressure drying unit configured to, after judging that the water bath heating is qualified, load the aerogel to be dried into a sheet-like mold, and then place the sheet-like mold in a drying chamber to perform atmospheric pressure drying; when normal-pressure drying is carried out, determining the initial rotating speed of a drying fan according to the arrangement density of the flaky mould;

the rotating speed adjusting unit is configured to collect the real-time quality data of the aerogel to be dried, and judge whether to adjust the initial rotating speed according to the real-time quality data; and when the initial rotating speed is judged not to be adjusted, stopping the drying fan if the real-time quality data does not change within the preset time.

It can be appreciated that the above-mentioned method and system for drying silica-based aerogel under normal pressure have the same beneficial effects, and will not be described herein.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:

FIG. 1 is a flow chart of a method for atmospheric drying of silica-based aerogels according to an embodiment of the present invention;

FIG. 2 is a block diagram of an atmospheric drying system for silica-based aerogels according to an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other. The invention will be described in detail below with reference to the drawings in connection with embodiments.

Silica-based aerogels are a special porous material consisting of three-dimensional network of silica or silicon-containing compounds. The microstructure of the porous ceramic has high porosification, so that the porous ceramic has extremely high specific surface area and rich pore structure, and thus, the porous ceramic is endowed with a plurality of unique properties and applications. There are some obvious problems in the current normal pressure drying process of silicon-based aerogel, which limit the preparation quality of aerogel and increase the uncertainty in the production process. For example, under the normal pressure drying method, the discharging speed of moisture inside the aerogel is affected by external environmental conditions and worker's operation skills, which easily results in uneven drying. The inconsistent moisture removal rates from different portions can lead to uneven shrinkage of the aerogel during drying, thereby affecting the overall structure and performance of the aerogel. The normal pressure drying method has lower cost compared with supercritical drying, but because the drying effect is influenced by the experience of operators, more time and manpower are needed for monitoring and adjusting, and the complexity and cost of the production process are increased. Therefore, it is necessary to design an atmospheric drying method and system for silica-based aerogel in order to solve the problems existing in the conventional atmospheric drying.

Referring to fig. 1, the embodiment provides a method for drying silica-based aerogel under normal pressure, which includes:

s100: and (3) sealing the sol to be dried, heating in a water bath, and collecting the mass and the real-time temperature of the sol to be dried.

S200: and determining the stirring time and the initial stirring rate when the water bath is heated according to the mass of the sol to be dried, adjusting the initial stirring rate according to the real-time temperature, and completing the stirring of the gel at the adjusted stirring rate to obtain the aerogel to be dried.

S300: and acquiring viscosity data of the aerogel to be dried, and judging whether water bath heating is qualified or not according to the viscosity data.

S400: and after the water bath heating is judged to be qualified, loading the aerogel to be dried into a flaky mould, and then placing the flaky mould into a drying chamber for normal pressure drying. When normal pressure drying is carried out, the initial rotation speed of the drying fan is determined according to the arrangement density of the flaky mould.

S500: and acquiring real-time quality data of the aerogel to be dried, and judging whether to adjust the initial rotating speed according to the real-time quality data. And when the initial rotating speed is judged not to be adjusted, stopping the drying fan if the real-time quality data does not change within the preset time.

Specifically, the preparation process of the sol to be dried comprises the following steps: the ethyl orthosilicate and the ethanol are uniformly mixed according to a preset volume ratio to obtain a solution 1. Nitric acid and ethanol were mixed well as solution 2. Solution 1 was added dropwise to solution 1 and continuously stirred to give solution 3. And adding a surfactant into the solution 3, and stirring and mixing uniformly. Ammonia water, water and ethanol are mixed uniformly in proportion to obtain a solution 4. And (3) dropwise adding the solution 4 into the solution 3, and continuously stirring to obtain the sol to be dried.

In particular, the purpose of sealing the sol to be dried is to prevent the sol from being affected by the external environment during the water bath gel process, in particular to avoid evaporation and volatilization of the water in the sol. The seal is effective to maintain the initial composition and moisture content of the sol to ensure that the structure and performance of the aerogel is not compromised during the drying process. The water bath heating is a process of placing the sealed sol to be dried in water, and gradually heating and gelling the sol through heat conduction of the water. This step serves to convert the liquid sol into a gel state, i.e., to condense the liquid portion of the sol into a solid structure. The water bath heating helps to provide a uniform heating environment, uniformly distribute the components in the sol, and maintain the stability of the gel structure by heat conduction. Meanwhile, the water bath heating is also beneficial to controlling the rate of gel, and excessively fast or excessively slow gel is avoided, so that the final performance and quality of the aerogel are ensured. After the sol is heated in water bath to be qualified, the sol is filled into a flake-shaped mold, so that the preparation of the mold is realized, and then the normal-pressure drying is carried out. The standard of the end of drying is that the quality data of the aerogel to be dried does not change within a preset time, at this time, the moisture in the aerogel is discharged to finish the drying operation, and the preset time refers to that once the real-time quality data is judged not to change any more in the normal pressure drying process of the silica-based aerogel, and the operation of the drying fan is stopped after a preset period of time. This preset time is set to ensure stability and rationality of the drying process. Once the real-time quality data has remained stable for a period of time, meaning that the aerogel to be dried has reached the desired degree of dryness, the drying process is substantially complete. It is intended to avoid excessive drying, thereby maintaining the optimal performance and structure of the aerogel. The length of the preset time can be set according to the specific aerogel properties, drying conditions and production experience. A shorter preset time is suitable for some aerogels that are easy to dry, while a longer preset time is suitable for cases where longer drying is required.

It can be appreciated that the challenges of normal pressure drying in the current silica-based aerogel preparation, such as uneven drying, aerogel quality fluctuation, and the like, are solved by a comprehensive and fine step design and intelligent control system. The method effectively ensures the preparation quality and stability of the aerogel.

In some embodiments of the present application, determining the agitation time and initial agitation rate at the time of heating in the water bath according to the mass of the sol to be dried in step S200 includes: the first preset mass M1, the second preset mass M2 and the third preset mass M3 are preset, and M1 is more than M2 and less than M3. The method comprises the steps of presetting a first preset stirring time T1, a second preset stirring time T2 and a third preset stirring time T3, wherein T1 is more than T2 and less than T3. The first preset stirring rate Vj1, the second preset stirring rate Vj2 and the third preset stirring rate Vj3 are preset, and Vj1 is smaller than Vj2 and smaller than Vj3. And determining the stirring time and the initial stirring rate when the water bath is heated according to the size relation between the mass M of the sol to be dried and each preset mass. When M1 is less than or equal to M2, determining the stirring time to be T1 during heating in water bath, and determining the initial stirring rate to be Vj1. When M2 is less than or equal to M3, determining the stirring time to be T2 during heating in water bath, and determining the initial stirring rate to be Vj2. When M3 is less than or equal to M, the stirring time during heating in the water bath is determined to be T3, and the initial stirring rate is determined to be Vj3.

Specifically, before the sol to be dried is filled in the sealed container, the mass of the container is recorded first, then the sol is filled in the container, the container is weighed again, and the mass of the sol can be calculated through the change of the mass. A temperature sensor is used in the water bath to monitor the real-time temperature. These sensors may be either contact type, such as thermocouples or resistance thermometers, or non-contact type, such as infrared temperature sensors. The temperature can be measured in real time by placing the temperature sensor in a water bath or in contact with the container. The preset mass change rate is determined in advance before starting the water bath heating. This rate of change is set according to the desired aerogel properties and experiments and can be expressed as the rate of change of sol mass per unit time. The initial stirring time and the initial stirring rate are determined according to the mass change rate.

Specifically, by presetting three preset mass thresholds and arranging the mass thresholds according to the size relation, the association between the mass and the stirring parameter is established. Meanwhile, according to different mass ranges, corresponding preset stirring time and initial stirring speed are set so as to meet the stirring requirements under different masses. For example, when the mass of the sol to be dried is between M1 and M2, the first preset stirring time T1 and the first preset stirring rate Vj1 are employed to ensure uniform mixing and gelation of the sol. The stirring strategy can be adaptively adjusted according to the change of the sol quality, and more accurate drying process control is realized.

It can be appreciated that by the associative setting of the mass and the stirring parameters, the stirring process is tightly combined with the sol mass, thereby realizing more intelligent and accurate drying operation. By adopting different stirring time and different stirring speed corresponding to different mass ranges, the gelation process of the sol can be fully adjusted, so that the structural uniformity and the performance stability of the aerogel are ensured. The intelligent regulation strategy effectively reduces human intervention in the preparation process and improves the consistency and stability of the preparation.

In some embodiments of the present application, after determining that the stirring time during heating in the water bath is Ti and the initial stirring rate is Vji, i=1, 2,3, the initial stirring rate is adjusted according to the real-time temperature in step S200, and the gel is stirred at the adjusted stirring rate, so as to obtain the aerogel to be dried, which includes: the first preset temperature W1, the second preset temperature W2 and the third preset temperature W3 are preset, and W1 is more than W2 and less than W3. The first preset rate adjustment coefficient A1, the second preset rate adjustment coefficient A2 and the third preset rate adjustment coefficient A3 are preset, and A1 is more than A2 and less than A3. And selecting a speed adjusting coefficient to adjust the initial stirring speed Vji according to the relation between the real-time temperature W and each preset temperature, and obtaining the adjusted stirring speed. When W1 is less than or equal to W2, a third preset rate adjustment coefficient A3 is selected to adjust the initial stirring rate Vji, and the adjusted stirring rate Vji is obtained. When W2 is less than or equal to W3, selecting a second preset rate adjustment coefficient A2 to adjust the initial stirring rate Vji, and obtaining an adjusted stirring rate Vji.A2. When W3 is less than or equal to W, a first preset rate adjustment coefficient A1 is selected to adjust the initial stirring rate Vji, and the adjusted stirring rate Vji A1 is obtained.

Specifically, after the water bath heating is started, the temperature of the sol to be dried needs to be monitored in real time. This may be achieved by placing a temperature sensor in the sol container or using other temperature monitoring devices. The stirring rate is adjusted according to the real-time temperature data, and can be preset to automatically adjust the stirring rate in a specific temperature range. If the real-time temperature exceeds the preset upper limit, it is indicated that the sol temperature is too high, resulting in non-uniform gelation. In this case, the stirring rate is reduced to slow down the heat transfer rate, preventing overheating. If the real-time temperature is below the preset lower limit, this indicates that the sol temperature is too low, resulting in too slow a gelation rate. In this case, the stirring rate is increased to increase the heat conduction rate and accelerate gelation.

Specifically, the temperature of the water bath is not too high to damage the aerogel structure due to the characteristic of heating in the water bath, so that the stirring rate is adjusted according to the temperature to accelerate the gel process. Since temperature affects the evaporation rate of the solvent, while the stirring rate affects the surface area of the gel and the gas diffusion rate. Reasonable temperature and stirring rate can cooperate to realize faster evaporation rate and uniform gas diffusion, thereby avoiding the problems of uneven shrinkage, deformation or cracking in the aerogel drying process. The choice of temperature and stirring rate also affects the stability and final properties of the gel. Too high or too low stirring rates may result in unstable gel structures, affecting the physical and chemical properties of the aerogel. Therefore, when the temperature is lower, the stirring is accelerated so that the water bath gel step is completed more quickly, and when the temperature is higher, the stirring speed is properly reduced so as to ensure the gel quality.

It will be appreciated that by correlating the real-time temperature to the rate adjustment factor, a more intelligent and adaptive drying operation is achieved by closely combining the agitation rate with the temperature change. Different speed adjusting coefficients are selected according to different temperature ranges, so that the mixing and gelation process of the sol can be effectively controlled, and the uniformity and quality stability of the aerogel are ensured.

In some embodiments of the present application, after selecting the i-th preset rate adjustment coefficient Ai to adjust the initial stirring rate Vji and obtaining the adjusted stirring rate Vji ×ai, i=1, 2,3, the step S300 of collecting viscosity data of the aerogel to be dried, and judging whether the heating of the water bath is qualified according to the viscosity data includes: and presetting a viscosity threshold Nmax, and judging whether the water bath heating is qualified or not according to the relationship between the viscosity data N of the aerogel to be dried and the viscosity threshold Nmax. And when N is more than or equal to Nmax, judging that the water bath heating is qualified, and drying the aerogel to be dried under normal pressure. And when N is less than Nmax, judging that the water bath heating is unqualified, and performing secondary water bath heating on the aerogel to be dried.

Specifically, the viscosity threshold is a threshold set during the aerogel preparation process, and is used to determine whether the viscosity of the aerogel reaches a desired dryness. The viscosity threshold is set based on the nature and practical application requirements of the aerogel. A rotational viscometer can be used to measure the degree of viscosity of a liquid or gel. The method calculates viscosity indirectly by measuring the torque required during rotation. Or using a rheometer to measure the flowability of a liquid or gel under different shear stresses to give viscosity data.

It can be understood that by introducing a determination mechanism of viscosity data in the preparation process, the normal pressure drying method can more accurately control the time of heating in a water bath and ensure that the aerogel reaches a proper drying degree before normal pressure drying, thereby effectively solving the problem that the drying effect is influenced by the experience of workers in the traditional normal pressure drying method and improving the preparation efficiency and consistency of the aerogel.

In some embodiments of the present application, when it is determined that the water bath heating is not acceptable and the aerogel to be dried is subjected to the secondary water bath heating in step S300, the method includes: obtaining a viscosity difference delta N=Nmax-N between the viscosity data N and a viscosity threshold Nmax, and presetting a first preset viscosity difference delta N1, a second preset viscosity difference delta N2 and a third preset viscosity difference delta N3, wherein delta N1 is less than delta N2 is less than delta N3. And determining the stirring time during the heating of the secondary water bath according to the relation between the viscosity difference delta N and each preset viscosity difference. The method comprises the steps of presetting a first preset secondary stirring time R1, a second preset secondary stirring time R2 and a third preset secondary stirring time R3, wherein R1 is smaller than R2 and smaller than R3. When DeltaN 1 is less than or equal to DeltaN < DeltaN2, determining the stirring time during the secondary water bath heating as R1. When DeltaN 2 is less than or equal to DeltaN < DeltaN3, determining the stirring time during the secondary water bath heating as R2. When delta N3 is less than or equal to delta N, determining the stirring time during the heating in the secondary water bath as R3.

Specifically, in order to better control the secondary water bath heating process, different viscosity difference thresholds, i.e., Δn1, Δn2, and Δn3, are preset, and first, second, and third preset secondary stirring times R1, R2, and R3 are set correspondingly, respectively. By comparing the actual Δn with these preset thresholds, it can be determined how long it takes to heat up the secondary water bath to achieve the desired gel effect.

Specifically, after one water bath heating, the water bath heating device is not stopped when the viscosity measurement is performed, but is kept in a heated state. This is to keep the aerogel sample at a relatively constant temperature for the viscosity measurement in order to obtain accurate viscosity data. If the water bath heating is stopped at the time of the viscosity measurement, the sample temperature may be lowered, resulting in inaccurate viscosity data. On the other hand, in the case of the secondary heating, the temperature and stirring speed are continued according to the parameters determined once. The purpose of this design is to ensure that the operation in the secondary heating stage is consistent with that in the primary heating stage, so that the heating process and viscosity variation can be better controlled. By maintaining similar operating conditions, the efficiency and consistency of aerogel production can be substantially maintained.

It can be appreciated that the stirring time of the secondary water bath heating is dynamically adjusted according to the actual situation, so as to ensure that the aerogel reaches the expected dryness in the secondary heating process. By introducing the concept of the difference of the viscosity and the threshold value, the method can more intelligently judge when the secondary water bath heating is needed, so that the efficiency and consistency of aerogel preparation are improved, and excessive or insufficient heating is avoided.

In some embodiments of the present application, when the normal pressure drying is performed after the water bath heating is qualified in step S400, determining the initial rotation speed of the drying fan according to the arrangement density of the flake-shaped mold includes: the first preset rotating speed Z1, the second preset rotating speed Z2 and the third preset rotating speed Z3 are preset, and Z1 is more than Z2 and less than Z3. The first preset arrangement density P1, the second preset arrangement density P2 and the third preset arrangement density P3 are preset, and P1 is more than P2 and less than P3. And determining the initial rotating speed of the drying fan according to the relation between the arrangement density P0 of the lamellar mould and each preset arrangement density. When P1 is less than or equal to P0 and less than P2, determining the initial rotating speed of the drying fan as Z3. When P2 is less than or equal to P0 and less than P3, determining the initial rotating speed of the drying fan as Z2. When P3 is less than or equal to P0, the initial rotation speed of the drying fan is determined to be Z1.

Specifically, the initial rotation speeds of the drying fans at different arrangement densities are preset, and are respectively represented by Z1, Z2 and Z3, and Z1 is more than Z2 and less than Z3. Meanwhile, first, second and third preset arrangement densities P1, P2 and P3 corresponding to the arrangement densities are preset, and P1 < P2 < P3. The initial rotation speed of the drying fan is determined by comparing the magnitude relation between the arrangement density P0 of the lamellar mold and each preset arrangement density.

In particular, a higher arrangement density results in a reduced gap between the lamellar moulds, a faster heat transfer and a slower heat dissipation, so that a higher rotational speed is required to ensure the drying effect. Conversely, a lower arrangement density may result in a relatively faster heat transfer, where a lower rotational speed is required to avoid excessive drying.

It can be understood that the method for setting and adjusting the initial rotation speed of the drying fan is beneficial to realizing a more accurate normal-pressure drying process according to the characteristics of aerogel samples with different arrangement densities, improves the drying efficiency and uniformity, and promotes the quality and production efficiency of the silicon-based aerogel. The arrangement density refers to the distribution density of the lamellar mold in a unit area, and the rotation speed refers to the rotation speed of the drying fan. The different arrangement densities affect the accumulation and ventilation of the aerogel in the mould and thus the heat and humidity distribution during drying. Therefore, in order to ensure uniformity and efficiency of drying, it is necessary to adjust the initial rotation speed of the fan according to different arrangement densities.

In some embodiments of the present application, after selecting the i-th preset rotation speed Zi as the initial rotation speed, i=1, 2,3, the step S500 of collecting real-time quality data of the aerogel to be dried, and determining whether to adjust the initial rotation speed according to the real-time quality data includes: and acquiring a quality data change rate L0 according to the real-time quality data, presetting a quality data change rate threshold Lmax, and judging whether to adjust the initial rotating speed according to the magnitude relation between the quality data change rate L0 and the quality data change rate threshold Lmax. When L0 is larger than or equal to Lmax, the initial rotation speed is judged to be required to be adjusted. When L0 < Lmax, it is determined that no adjustment is necessary to the initial rotational speed.

Specifically, the rate of change refers to the degree of change in real-time mass data of the aerogel to be dried over a period of time, which is used to measure the mass change during the drying process of the aerogel. The change rate threshold is used for judging whether the change of the aerogel quality exceeds a preset limit, so as to determine whether the initial rotating speed needs to be adjusted.

It is understood that the rotational speed is a parameter that controls the operation of the drying fan, directly affecting the drying speed of the aerogel. When the mass of the aerogel is changed greatly, that is, the change rate is high, it means that the drying speed is too high or too low, which may cause problems such as shrinkage, deformation and the like of the aerogel. In order to maintain the quality of aerogel preparation, the initial rotational speed needs to be adjusted according to the real-time change rate. If the rate of change exceeds a predetermined threshold, the system determines that the rotational speed needs to be adjusted to slow down or speed up the drying rate appropriately to stabilize the quality. In contrast, when the rate of change is within the threshold range, the system will consider the mass change to be relatively stable, and no rotational speed adjustment is required to maintain stable drying conditions. According to the real-time change rate, the rotating speed is intelligently adjusted so as to maintain the stability of the drying process and the preparation quality of the aerogel. Is beneficial to optimizing the normal pressure drying process and improving the production efficiency and the consistency of products.

In some embodiments of the present application, when it is determined that the initial rotation speed needs to be adjusted in step S500, the method includes: the first preset mass change rate L1, the second preset mass change rate L2 and the third preset mass change rate L3 are preset, and L1 is smaller than L2 and smaller than L3. The first preset rotating speed adjusting coefficient C1, the second preset rotating speed adjusting coefficient C2 and the third preset rotating speed adjusting coefficient C3 are preset, and C1 is more than C2 and less than C3.

Specifically, according to the magnitude relation between the quality data change rate L0 and each preset quality change rate, a rotation speed adjustment coefficient is selected to adjust the initial rotation speed Zi, and the adjusted rotation speed is obtained. When L1 is less than or equal to L0 and less than L2, a third preset rotating speed adjusting coefficient C3 is selected to adjust the initial rotating speed Zi, and the adjusted rotating speed Zi is obtained. When L2 is less than or equal to L0 and less than L3, a second preset rotating speed adjusting coefficient C2 is selected to adjust the initial rotating speed Zi, and the adjusted rotating speed Zi is obtained. When L3 is less than or equal to L0, a first preset rotating speed adjusting coefficient C1 is selected to adjust the initial rotating speed Zi, and the adjusted rotating speed Zi is obtained.

In some embodiments of the present application, after selecting the i-th preset rotation speed adjustment coefficient Ci to adjust the initial rotation speed Zi and obtaining the adjusted rotation speed Zi, i=1, 2,3, the adjusting the initial rotation speed in step S500 further includes: the method comprises the steps of obtaining real-time air flow velocity K0 around a lamellar die, and presetting a first preset flow velocity K1, a second preset flow velocity K2 and a third preset flow velocity K3, wherein K1 is smaller than K2 and smaller than K3. And selecting a rotation speed adjustment coefficient according to the relation between the real-time air flow rate K0 and each preset flow rate, performing secondary adjustment on the adjusted rotation speed Zi, and finishing normal-pressure drying at the rotation speed after secondary adjustment. When K1 is less than or equal to K0 and less than K2, selecting a third preset rotation speed adjustment coefficient C3 to carry out secondary adjustment on the adjusted rotation speed Zi, and obtaining the rotation speed Zi, ci and C3 after secondary adjustment. When K2 is less than or equal to K0 and less than K3, selecting a second preset rotation speed adjustment coefficient C2 to carry out secondary adjustment on the adjusted rotation speed Zi, and obtaining the rotation speed Zi, ci and C2 after secondary adjustment. When K3 is less than or equal to K0, a first preset rotation speed adjustment coefficient C1 is selected to carry out secondary adjustment on the adjusted rotation speed Zi, and the rotation speed Zi, ci and C1 after secondary adjustment are obtained.

Specifically, according to the relation between the quality data change rate and the preset quality change rate, a corresponding rotation speed adjustment coefficient is selected to adjust the initial rotation speed. Therefore, the system can intelligently adjust the rotating speed according to the actual quality change condition so as to maintain the stability of the drying process and avoid the aerogel quality problem caused by too fast or too slow drying.

Specifically, the real-time air flow rate refers to the flow rate of the dry indoor air, typically generated by a fan or other ventilation device. This flow rate can affect the heat and mass transfer during aerogel drying, thereby affecting the rate and uniformity of aerogel drying. Higher air flow rates can accelerate the evaporation of moisture from the aerogel, facilitating the drying process, but too high flow rates can result in too fast drying of the aerogel surface to prevent the removal of internal moisture, which can cause problems such as shrinkage, deformation or cracking of the aerogel. The relationship between real-time air flow rate and rotational speed requires a reasonable balance during aerogel drying. The proper real-time air flow rate and the proper real-time air rotation speed can promote the uniform discharge of the moisture, prevent the surface of the aerogel from being dried too fast and the internal moisture from being discharged smoothly, thereby ensuring the drying quality and consistency of the aerogel. According to different aerogel characteristics and drying conditions, the drying process can be optimized by adjusting the real-time air flow rate and the rotating speed, and an ideal aerogel drying effect can be obtained.

It can be understood that according to the relation between the quality data change rate and the preset quality change rate, a proper rotation speed adjustment coefficient is selected to realize intelligent adjustment of the drying rotation speed, so that the stability of the drying process is maintained, the quality problem of aerogel caused by too fast or too slow drying is avoided, and the drying uniformity and stability of the aerogel are improved. Through the reasonable balance between to real-time air velocity of flow and rotational speed, ensure that moisture can evenly discharge, prevent aerogel surface too fast drying and inside moisture can't smooth exhaust's problem. The quality problems of uneven shrinkage, deformation, cracks and the like in the aerogel drying process can be effectively reduced, and the preparation quality and consistency of the aerogel are improved. Through presetting different mass change rate thresholds, rotation speed adjustment coefficients and flow speed preset values, the system can adapt to different aerogel characteristics and drying conditions, and a flexible control strategy is realized. Not only improves the stability and controllability of the production process, but also reduces the dependence on the experience of operators and reduces human errors, thereby further improving the efficiency and quality of aerogel preparation.

Comparative example one, when the above technical scheme is applied:

Stirring effect: dynamic adjustment of the stirring rate was used to ensure uniform distribution. Results: the aerogel density was uniform without significant shrinkage or deformation. Data: aerogel density fluctuations are within ±2%. And (3) viscosity control: and carrying out water bath heating control according to the viscosity data. Results: the viscosity is kept within a suitable range. Data: the viscosity fluctuates in the range of 1000-1200 mPas. And (3) drying under normal pressure: the initial rotational speed of the drying fan is intelligently determined. Results: the drying process is stable, and the aerogel in the flake-shaped mold is uniformly dried. Data: the drying time was 4 hours and the aerogel in all flake-like moulds was dried uniformly. And (3) real-time quality control: and adjusting the rotating speed of the drying fan according to the real-time quality data. Results: the drying speed is adjusted to maintain the stability of the quality. Data: the change rate of the real-time quality data is within +/-1 percent. The quality of the final silicon-based aerogel product is similar, and the requirements can be met.

Comparative example two, the above technical scheme was not applied:

stirring effect: the stirring rate was fixed. Results: the aerogel is unevenly distributed and has shrinkage or deformation. Data: aerogel density fluctuates by + -5% and localized shrinkage occurs. And (3) viscosity control: no viscosity data control. Results: the viscosity fluctuation is large and unstable. Data: the viscosity fluctuates in the range of 800-1500 mPa.s. And (3) drying under normal pressure: the rotational speed of the drying fan is fixed. Results: the drying process is uneven, and the quality of the aerogel is affected. Data: the drying time is not stable and the aerogel in some flake-like molds is not completely dried. And (3) real-time quality control: there is no real-time quality data control. Results: the drying process is uncontrolled, leading to quality fluctuations. Data: the rate of change of the real-time quality data is within + -3%, and larger fluctuations occur. The quality difference of the final silicon-based aerogel product is larger, and the product loss rate reaches 30%.

In the above embodiment, the optimal stirring effect is achieved by determining the stirring time and the initial stirring rate during heating in the water bath according to the mass of the sol to be dried and adjusting the initial stirring rate according to the real-time temperature. The aerogel is ensured to be fully and uniformly distributed in the stirring process, and the problems of shrinkage, deformation and the like of the aerogel are reduced, so that the consistency and quality of preparation are improved. By collecting viscosity data of the aerogel to be dried and judging whether water bath heating is qualified or not, the method effectively evaluates the progress of the gel process, and avoids stopping the gel too early or too late, thereby further ensuring the quality and performance of the aerogel. The aerogel to be dried is put into a flake-form mold, and then is dried under normal pressure. The intelligent control of the drying process is realized by determining the initial rotation speed of the drying fan according to the arrangement density of the lamellar mould. The stability and consistency of the drying process are further ensured by collecting the real-time quality data and judging whether to adjust the initial rotating speed according to the real-time quality data.

In another preferred mode based on the above embodiment, referring to fig. 2, the present embodiment provides an atmospheric drying system for silica-based aerogel, including:

The water bath heating unit is configured to perform water bath heating after sealing the sol to be dried, and collect the mass and the real-time temperature of the sol to be dried;

the stirring adjusting unit is configured to determine the stirring time and the initial stirring rate during water bath heating according to the mass of the sol to be dried, adjust the initial stirring rate according to the real-time temperature, and finish stirring the gel at the adjusted stirring rate to obtain the aerogel to be dried;

the judging unit is configured to collect viscosity data of the aerogel to be dried and judge whether water bath heating is qualified or not according to the viscosity data;

an atmospheric pressure drying unit configured to, after judging that the water bath heating is qualified, put aerogel to be dried into a sheet-like mold, and then place the sheet-like mold in a drying chamber to perform atmospheric pressure drying; when normal-pressure drying is carried out, determining the initial rotating speed of a drying fan according to the arrangement density of the lamellar mould;

the rotating speed adjusting unit is configured to acquire real-time quality data of aerogel to be dried and judge whether to adjust the initial rotating speed according to the real-time quality data; and when the initial rotating speed is judged not to be adjusted, stopping the drying fan if the real-time quality data does not change within the preset time.

It can be appreciated that the above-mentioned method and system for drying silica-based aerogel under normal pressure have the same beneficial effects, and will not be described herein.

It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flowchart and/or block of the flowchart illustrations and/or block diagrams, and combinations of flowcharts and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Finally, it should be noted that: the above embodiments are only for illustrating the technical aspects of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above embodiments, it should be understood by those of ordinary skill in the art that: modifications and equivalents may be made to the specific embodiments of the invention without departing from the spirit and scope of the invention, which is intended to be covered by the claims.

Claims (2)

1. An atmospheric drying method for silica-based aerogel, characterized by comprising:

sealing the sol to be dried, heating in water bath, and collecting the mass and real-time temperature of the sol to be dried;

determining the stirring time and the initial stirring rate when the sol to be dried is heated in a water bath according to the mass of the sol to be dried, adjusting the initial stirring rate according to the real-time temperature, and completing the gel stirring at the adjusted stirring rate to obtain aerogel to be dried;

collecting viscosity data of the aerogel to be dried, and judging whether water bath heating is qualified or not according to the viscosity data;

after the water bath heating is judged to be qualified, loading the aerogel to be dried into a flaky mould, and then placing the flaky mould into a drying chamber for normal pressure drying; when normal-pressure drying is carried out, determining the initial rotating speed of a drying fan according to the arrangement density of the flaky mould;

collecting real-time quality data of the aerogel to be dried, and judging whether to adjust the initial rotating speed according to the real-time quality data;

when the initial rotating speed is judged not to be adjusted, stopping the drying fan if the real-time quality data does not change within a preset time;

Determining the stirring time and the initial stirring rate during water bath heating according to the mass of the sol to be dried, wherein the method comprises the following steps:

presetting a first preset mass M1, a second preset mass M2 and a third preset mass M3, wherein M1 is more than M2 and less than M3; presetting a first preset stirring time T1, a second preset stirring time T2 and a third preset stirring time T3, wherein T1 is more than T2 and less than T3; presetting a first preset stirring rate Vj1, a second preset stirring rate Vj2 and a third preset stirring rate Vj3, wherein Vj1 is less than Vj2 and less than Vj3;

determining the stirring time and the initial stirring rate when the water bath is heated according to the size relation between the mass M of the sol to be dried and each preset mass;

when M1 is less than or equal to M2, determining the stirring time during heating in the water bath as T1, and determining the initial stirring rate as Vj1;

when M2 is less than or equal to M3, determining the stirring time to be T2 during heating in the water bath, and determining the initial stirring rate to be Vj2;

when M3 is less than or equal to M, determining the stirring time during heating in the water bath as T3, and determining the initial stirring rate as Vj3;

when the stirring time during heating in a water bath is determined to be Ti, after the initial stirring rate is Vji, i=1, 2,3, the initial stirring rate is adjusted according to the real-time temperature, and gel stirring is completed at the adjusted stirring rate, so that aerogel to be dried is obtained, and the method comprises the following steps:

Presetting a first preset temperature W1, a second preset temperature W2 and a third preset temperature W3, wherein W1 is more than W2 and less than W3; presetting a first preset rate adjustment coefficient A1, a second preset rate adjustment coefficient A2 and a third preset rate adjustment coefficient A3, wherein A1 is more than A2 and less than A3;

according to the relation between the real-time temperature W and each preset temperature, selecting a speed adjusting coefficient to adjust the initial stirring speed Vji, and obtaining an adjusted stirring speed;

when W1 is less than or equal to W2, selecting the third preset rate adjustment coefficient A3 to adjust the initial stirring rate Vji, and obtaining an adjusted stirring rate Vji x A3;

when W2 is less than or equal to W3, selecting the second preset rate adjustment coefficient A2 to adjust the initial stirring rate Vji, and obtaining an adjusted stirring rate Vji;

when W3 is less than or equal to W, selecting the first preset rate adjustment coefficient A1 to adjust the initial stirring rate Vji, and obtaining an adjusted stirring rate Vji A1;

after selecting an i-th preset rate adjustment coefficient Ai to adjust an initial stirring rate Vji and obtaining an adjusted stirring rate Vji x Ai, i=1, 2 and 3, collecting viscosity data of aerogel to be dried, judging whether water bath heating is qualified according to the viscosity data, and comprising the following steps:

Presetting a viscosity threshold Nmax, and judging whether water bath heating is qualified or not according to the relationship between the viscosity data N of the aerogel to be dried and the viscosity threshold Nmax;

when N is more than or equal to Nmax, judging that the water bath is qualified in heating, and performing normal-pressure drying on the aerogel to be dried;

when N is less than Nmax, judging that the water bath heating is unqualified, and performing secondary water bath heating on the aerogel to be dried;

when the water bath heating is judged to be unqualified and the aerogel to be dried is subjected to secondary water bath heating, the method comprises the following steps:

acquiring a viscosity difference delta N=Nmax-N between the viscosity data N and a viscosity threshold value Nmax, and presetting a first preset viscosity difference delta N1, a second preset viscosity difference delta N2 and a third preset viscosity difference delta N3, wherein delta N1 is less than delta N2;

determining the stirring time during the heating of the secondary water bath according to the relationship between the viscosity difference delta N and each preset viscosity difference;

presetting a first preset secondary stirring time R1, a second preset secondary stirring time R2 and a third preset secondary stirring time R3, wherein R1 is more than R2 and less than R3;

when delta N1 is less than or equal to delta N < [ delta ] N2, determining the stirring time during the secondary water bath heating to be R1;

When delta N2 is less than or equal to delta N < [ delta ] N3, determining the stirring time during the secondary water bath heating to be R2;

when delta N3 is less than or equal to delta N, determining the stirring time during heating in the secondary water bath as R3;

when judging that the water bath heating is qualified and then performing normal-pressure drying, determining the initial rotating speed of the drying fan according to the arrangement density of the flaky mold, wherein the method comprises the following steps:

presetting a first preset rotating speed Z1, a second preset rotating speed Z2 and a third preset rotating speed Z3, wherein Z1 is more than Z2 and less than Z3; presetting a first preset arrangement density P1, a second preset arrangement density P2 and a third preset arrangement density P3, wherein P1 is more than P2 and less than P3;

determining the initial rotating speed of the drying fan according to the relation between the arrangement density P0 of the lamellar mould and each preset arrangement density;

when P1 is less than or equal to P0 and less than P2, determining the initial rotating speed of the drying fan as Z3;

when P2 is less than or equal to P0 and less than P3, determining the initial rotating speed of the drying fan as Z2;

when P3 is less than or equal to P0, determining the initial rotating speed of the drying fan as Z1;

after selecting an ith preset rotating speed Zi as the initial rotating speed, i=1, 2 and 3, collecting real-time quality data of the aerogel to be dried, and judging whether to adjust the initial rotating speed according to the real-time quality data, wherein the method comprises the following steps:

Acquiring a quality data change rate L0 according to real-time quality data, presetting a quality data change rate threshold Lmax, and judging whether to adjust the initial rotating speed according to the magnitude relation between the quality data change rate L0 and the quality data change rate threshold Lmax;

when L0 is more than or equal to Lmax, judging that the initial rotation speed needs to be adjusted;

when L0 is less than Lmax, judging that the initial rotation speed does not need to be adjusted;

when it is determined that the initial rotation speed needs to be adjusted, the method includes:

presetting a first preset mass change rate L1, a second preset mass change rate L2 and a third preset mass change rate L3, wherein L1 is more than L2 and less than L3; presetting a first preset rotating speed adjusting coefficient C1, a second preset rotating speed adjusting coefficient C2 and a third preset rotating speed adjusting coefficient C3, wherein C1 is more than C2 and less than C3;

according to the magnitude relation between the quality data change rate L0 and each preset quality change rate, selecting a rotation speed adjustment coefficient to adjust the initial rotation speed Zi, and obtaining an adjusted rotation speed;

when L1 is less than or equal to L0 and less than L2, selecting a third preset rotating speed adjustment coefficient C3 to adjust the initial rotating speed Zi, and obtaining an adjusted rotating speed Zi×C3;

when L2 is less than or equal to L0 and less than L3, selecting a second preset rotating speed adjustment coefficient C2 to adjust the initial rotating speed Zi, and obtaining an adjusted rotating speed Zi×C2;

When L3 is less than or equal to L0, a first preset rotating speed adjusting coefficient C1 is selected to adjust the initial rotating speed Zi, and the adjusted rotating speed Zi is obtained;

after the i-th preset rotation speed adjustment coefficient Ci is selected to adjust the initial rotation speed Zi and the adjusted rotation speed Zi is obtained, i=1, 2,3, and the initial rotation speed is adjusted, and the method further includes:

acquiring a real-time air flow rate K0 around the lamellar mould, and presetting a first preset flow rate K1, a second preset flow rate K2 and a third preset flow rate K3, wherein K1 is smaller than K2 and smaller than K3; according to the relation between the real-time air flow velocity K0 and each preset flow velocity, selecting a rotation speed adjustment coefficient to secondarily adjust the adjusted rotation speed Zi, and finishing normal-pressure drying at the secondarily adjusted rotation speed;

when K1 is less than or equal to K0 and less than K2, selecting the third preset rotating speed adjusting coefficient C3 to carry out secondary adjustment on the adjusted rotating speed Zi, and obtaining the rotating speed Zi, ci and C3 after secondary adjustment;

when K2 is less than or equal to K0 and less than K3, selecting the second preset rotating speed adjusting coefficient C2 to carry out secondary adjustment on the adjusted rotating speed Zi, and obtaining the rotating speed Zi, ci and C2 after secondary adjustment;

when K3 is less than or equal to K0, selecting the first preset rotation speed adjustment coefficient C1, and performing secondary adjustment on the adjusted rotation speed zi×ci to obtain a rotation speed zi×ci×c1 after secondary adjustment.

2. An atmospheric drying system for silica-based aerogel, applying the atmospheric drying method for silica-based aerogel according to claim 1, characterized by comprising:

the water bath heating unit is configured to perform water bath heating after sealing the sol to be dried, and collect the mass and the real-time temperature of the sol to be dried;

the stirring adjustment unit is configured to determine the stirring time and the initial stirring rate when the sol to be dried is heated in a water bath according to the mass of the sol to be dried, adjust the initial stirring rate according to the real-time temperature, and complete the gel stirring at the adjusted stirring rate to obtain the aerogel to be dried;

the judging unit is configured to collect viscosity data of the aerogel to be dried and judge whether water bath heating is qualified or not according to the viscosity data;

an atmospheric pressure drying unit configured to, after judging that the water bath heating is qualified, load the aerogel to be dried into a sheet-like mold, and then place the sheet-like mold in a drying chamber to perform atmospheric pressure drying; when normal-pressure drying is carried out, determining the initial rotating speed of a drying fan according to the arrangement density of the flaky mould;

the rotating speed adjusting unit is configured to collect the real-time quality data of the aerogel to be dried, and judge whether to adjust the initial rotating speed according to the real-time quality data; and when the initial rotating speed is judged not to be adjusted, stopping the drying fan if the real-time quality data does not change within the preset time.