Silica gel dehumidifying bed and preparation method thereof
By laying silica gel powder of different mesh sizes on the dehumidification bed substrate and immersing it in silica gel solution, combined with hygroscopic salt treatment, the problems of easy silica gel particle shedding and low coating density are solved, achieving more efficient dehumidification performance and a longer service life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHUHAI GLICK TECH CO LTD
- Filing Date
- 2023-03-01
- Publication Date
- 2026-06-26
AI Technical Summary
Existing silica gel dehumidification beds suffer from problems such as easy shedding of silica gel particles, low coating density, and poor adsorption performance, leading to loss of dehumidification performance and pore blockage.
By laying silica gel powder of different mesh sizes on the dehumidification bed substrate and immersing it in silica gel solution, combined with the use of hydrolysis solution of hygroscopic salt, the specific surface area is increased and the adhesion of silica gel particles is improved, forming a silicon-oxygen bond and avoiding pore blockage.
It effectively reduces silica gel particle shedding, improves coating density and adsorption performance, and extends the service life and dehumidification capacity of the dehumidification bed.
Smart Images
Figure BDA0004103890610000061
Abstract
Description
Technical Field
[0001] This invention relates to the field of dehumidification and air conditioning technology, specifically to a silica gel dehumidification bed and its preparation method. Background Technology
[0002] Solid adsorption dehumidification technology is commonly used to dry gases in applications requiring low humidity. Its basic forms include fixed-bed and rotating-bed (such as dehumidification beds). Existing solid adsorption dehumidification beds rely on adsorbents for moisture absorption. After saturation, they can be recycled through heating regeneration. Common adsorbents used include silica gel, molecular sieves, alumina, calcium chloride, potassium chloride, and lithium chloride. These adsorbents are typically granular or layered, bonded to a substrate or support material using methods such as bonding or sol-gel. Silica gel is a commonly used dehumidification material in solid dehumidification beds due to its advantages: safety, non-toxicity, low cost, good thermal stability, and good adsorption characteristics for water vapor over a wide relative humidity range. However, existing technologies suffer from low silica gel coating density, easy particle detachment, and poor adsorption performance. Summary of the Invention
[0003] The first objective of this invention is to provide a method for preparing a silica gel dehumidifying bed. The silica gel dehumidifying bed prepared by this method not only effectively reduces the number of silica gel particles falling off and reduces the loss of dehumidification performance, but also increases the silica gel coating density without causing blockage of the dehumidifying bed pores, thereby improving the dehumidification capacity of the dehumidifying bed.
[0004] A second objective of this invention is to provide a silica gel dehumidifying bed prepared by the above-described method.
[0005] To achieve the aforementioned first objective, the present invention provides a method for preparing a silica gel dehumidifying bed, comprising: step one, immersing a dehumidifying bed substrate in a viscous emulsion; step two, distributing a first type of silica gel powder onto the dehumidifying bed substrate impregnated with the viscous emulsion obtained in step one; step three, drying and curing the dehumidifying bed substrate with the silica gel powder layer; step four, immersing the dried and cured dehumidifying bed substrate in a silica gel solution; and step five, drying and curing the dehumidifying bed substrate impregnated with the silica gel solution obtained in step four.
[0006] As can be seen from the above scheme, after laying the silica powder layer and drying and curing, the specific surface area is increased by immersing the dehumidification bed substrate in the silica solution. At the same time, the colloidal particles are firmly attached to the surface of the silica particles on the dried and cured dehumidification bed substrate, and the particles form a silicon-oxygen bond, which firmly binds the silica particles to the dehumidification bed substrate, greatly improving the adhesion of the silica particles, thereby improving the durability of the dehumidification effect of the dehumidification bed and the service life of the dehumidification bed.
[0007] A preferred embodiment is that, between step two and step three, the preparation method further includes a step of laying a second type of silica powder; the step of laying the second type of silica powder is: spreading the second type of silica powder on the dehumidification bed substrate with the first type of silica powder attached obtained in step two.
[0008] Therefore, by applying silica powder again, the gaps between the silica powder can be filled, thereby increasing the coating density of silica on the dehumidification bed substrate.
[0009] A further option is that the mesh size of the second type of silica powder is greater than that of the first type of silica powder; and / or the mesh size of the first type of silica powder is in the range of 20 to 100 mesh; and / or the mesh size of the second type of silica powder is in the range of 120 to 300 mesh.
[0010] It can be seen that by laying two different particle sizes of silica powder, the smaller silica powder can fill the gaps between the larger silica powder, thereby further increasing the coating density of silica on the dehumidification bed substrate.
[0011] A preferred embodiment is that the preparation method of the silica gel dehumidifying bed further includes: step six, immersing the dehumidifying bed substrate with a silica gel layer obtained in step five in a hydrolysis solution of hygroscopic salt; step seven, drying the impregnated dehumidifying bed substrate obtained in step six to obtain the silica gel dehumidifying bed.
[0012] It is evident that current methods to improve dehumidification capacity generally involve increasing the amount of silica gel adhering to the surface. However, this approach can clog the honeycomb pores of the dehumidification bed. In contrast, this invention further enhances the hygroscopic properties of the coating by immersing the dehumidification bed substrate with attached silica gel particles in a hydrolyzed solution of hygroscopic salts. This ensures greater dehumidification capacity with the same thickness of silica gel coating. Therefore, the silica gel dehumidification bed prepared by this method not only effectively reduces the amount of silica gel particles detached, minimizing dehumidification performance loss, but also increases the silica gel coating density without clogging the dehumidification bed pores, thereby improving the dehumidification capacity of the dehumidification bed.
[0013] A further approach is to repeat steps four and five at least once before step six.
[0014] Therefore, it can be seen that by repeatedly impregnating the silicone solution, the coating density of the silicone layer can be further increased.
[0015] A preferred embodiment is that the hygroscopic salt is at least one of lithium chloride and potassium formate; and / or the mass fraction of the hygroscopic salt is 5% to 30%.
[0016] Therefore, lithium chloride and potassium formate can improve the moisture absorption of silica gel dehumidifier beds.
[0017] A preferred embodiment is that, in step one, the dehumidifying bed substrate is immersed in the viscous emulsion for a time ranging from 1 minute to 60 minutes; and / or in step four, the dried and cured dehumidifying bed substrate is immersed in the silica gel solution for a time ranging from 0.5 hours to 3 hours. And / or, in at least one of steps three and five, the drying temperature is in the range of 80°C to 120°C, and the drying time for at least one is in the range of 1 hour to 6 hours.
[0018] A preferred embodiment is that the viscous emulsion is an aqueous acrylic resin emulsion, and / or the silica gel solution concentration is 20% to 40%.
[0019] A preferred option is that the dehumidification bed substrate is a honeycomb panel, a wet curtain, or a heat exchanger.
[0020] Therefore, it can be seen that using existing honeycomb panels as a substrate is inexpensive and readily available. In addition, the dehumidification bed substrate made of metal has high stability, good thermal conductivity, and low thermal resistance, which is beneficial for the regeneration of silica gel and dehumidification.
[0021] A preferred embodiment is that, prior to step one, the preparation method further includes a pretreatment step for the dehumidification bed substrate; in the pretreatment step, the dehumidification bed substrate is first immersed in a sodium hydroxide solution to remove grease and impurities, and then cleaned with water and ethanol.
[0022] Therefore, by pre-treating the dehumidification bed substrate, the cleanliness of the dehumidification bed substrate surface is ensured, thereby increasing the coating density of the silicone layer and the adhesion between the silicone layer and the dehumidification bed substrate, and preventing the silicone particles in the silicone layer from falling off.
[0023] To achieve the second objective mentioned above, the present invention provides a silica gel dehumidifying bed, which is manufactured by the above-described preparation method; the silica gel dehumidifying bed includes a dehumidifying bed substrate and a dehumidifying agent disposed on the surface of the dehumidifying bed substrate. Detailed Implementation
[0024] The silica gel dehumidifying bed in this embodiment includes a dehumidifying bed substrate and a desiccant disposed on the surface of the dehumidifying bed substrate. The silica gel dehumidifying bed is manufactured by the following preparation method.
[0025] The preparation method of the silica gel dehumidification bed includes the following steps:
[0026] Step 1: Pre-treatment of the dehumidification bed substrate: Immerse the dehumidification bed substrate in sodium hydroxide solution to remove grease and impurities, and then clean it with water and ethanol.
[0027] Step two: Immerse the dehumidifying bed substrate in the viscous emulsion for a period ranging from 1 minute to 60 minutes. Preferably, the viscous emulsion is an aqueous acrylic resin emulsion.
[0028] Step 3: Distribute the first type of silica gel powder onto the dehumidifying bed substrate impregnated with the viscous emulsion obtained in Step 2.
[0029] Step four: Distribute the second type of silica gel powder onto the dehumidification bed substrate with the first type of silica gel powder attached in step three. The mesh size of the second type of silica gel powder is greater than that of the first type of silica gel powder, with the first type of silica gel powder having a mesh size in the range of 20 to 100 mesh, and the second type of silica gel powder having a mesh size in the range of 120 to 300 mesh.
[0030] Step 5: Dry and cure the dehumidification bed substrate with the silicone powder layer. The drying temperature is in the range of 80℃ to 120℃ and the drying time is in the range of 1 hour to 6 hours.
[0031] Step 6: Immerse the dried and cured dehumidified bed substrate in a silica gel solution with a concentration of 20% to 40% for 0.5 to 3 hours.
[0032] Step 7: Dry and cure the dehumidified bed substrate impregnated with silica gel solution obtained in Step 6. The drying temperature is in the range of 80℃ to 120℃ and the drying time is in the range of 1 hour to 6 hours.
[0033] Step 8: Immerse the dehumidifying bed substrate with silica gel layer obtained in step 7 in a hydrolysis solution of hygroscopic salt. Preferably, the hygroscopic salt is at least one of lithium chloride and potassium formate. The mass fraction of the hygroscopic salt in the hydrolysis solution is 5% to 30%, and the immersion time is in the range of 1 minute to 60 minutes.
[0034] Step 9: Dry the impregnated dehumidifying bed substrate obtained in Step 8 to obtain a silica gel dehumidifying bed. The drying temperature is in the range of 80℃ to 120℃, and the drying time is in the range of 1 hour to 6 hours.
[0035] Alternatively, steps six and seven can be repeated at least once before step eight. The dehumidifying bed substrate can be a honeycomb panel, a wet curtain, or a heat exchanger. In the following embodiments, the dehumidifying bed substrate uses a metal aluminum-based honeycomb panel. Steps eight and nine can also be omitted, i.e., the impregnation with the hydrolysis solution of the hygroscopic salt can be skipped. The hydrolysis solution of the hygroscopic salt can be prepared temporarily before step eight or prepared in advance. The above modifications can also achieve the purpose of the present invention.
[0036] First embodiment of silica gel dehumidifying bed and its preparation method:
[0037] In this embodiment, the preparation method of the silica gel dehumidification bed includes the following steps:
[0038] Step 1: Take the aluminum-based honeycomb panel and pre-treat its surface: Immerse the aluminum-based honeycomb panel in a 1g / L sodium hydroxide solution to remove grease and impurities, and then clean it with water and ethanol.
[0039] Step 2: Immerse the aluminum-based honeycomb panel in water-based acrylic resin emulsion and remove it after 30 minutes.
[0040] Step 3: Evenly distribute 60-80 mesh silica gel powder onto the aluminum-based honeycomb plate impregnated with water-based acrylic resin emulsion obtained in Step 2, and remove any excess unattached silica gel powder.
[0041] Step four: evenly distribute 150-200 mesh silica gel powder onto the aluminum-based honeycomb plate with 60-80 mesh silica gel powder attached in step three, and remove any excess unattached silica gel powder.
[0042] Step 5: Place the aluminum-based honeycomb panel with the silicone powder layer in an oven at 120°C for 3 hours to dry and cure.
[0043] Step 6: Immerse the dried and cured aluminum-based honeycomb panel in a 30% silica gel solution and remove it after soaking for 2 hours.
[0044] Step 7: Place the aluminum-based honeycomb panel impregnated with silicone solution obtained in Step 6 into an oven at 120°C for 3 hours to dry and cure.
[0045] Step 8: Immerse the dried and cured aluminum-based honeycomb panel in a 30% silica gel solution for 2 hours and then remove it.
[0046] Step 9: Place the aluminum-based honeycomb panel impregnated with silicone solution obtained in Step 8 into a 120°C oven for 3 hours to dry and cure.
[0047] Step 10: Prepare a hydrolysis solution of potassium formate, with water comprising 80% by mass and potassium formate comprising 20% by mass, and mix them thoroughly.
[0048] Step 11: Immerse the aluminum-based honeycomb panel in the hydrolysis solution prepared in Step 10, and remove it after soaking for 30 minutes.
[0049] Step 12: Remove the impregnated aluminum-based honeycomb panel and place it in a 120℃ oven for 3 hours to dry and cure. Weigh the panel to obtain a silicone coating density of 0.22 kg / m² on the surface of the silicone dehumidification bed. 2 .
[0050] Second embodiment of silica gel dehumidifying bed and its preparation method:
[0051] As a description of the second embodiment of the silica gel dehumidifying bed and its preparation method of the present invention, the following description only focuses on the differences from the first embodiment of the silica gel dehumidifying bed and its preparation method described above.
[0052] In this embodiment, the silica gel powder dispersed on the aluminum-based honeycomb plate impregnated with aqueous acrylic resin emulsion in step three is 40 to 80 mesh. The resulting silica gel dehumidification bed has a surface silica gel coating density of 0.24 kg / m³. 2 .
[0053] Third embodiment of silica gel dehumidifying bed and its preparation method:
[0054] As a description of the third embodiment of the silica gel dehumidifying bed and its preparation method of the present invention, the following description only focuses on the differences from the first embodiment of the silica gel dehumidifying bed and its preparation method described above.
[0055] In this embodiment, the silica gel powder dispersed on the aluminum-based honeycomb plate impregnated with aqueous acrylic resin emulsion in step three is 40-60 mesh. The resulting silica gel dehumidification bed has a surface silica gel coating density of 0.29 kg / m³. 2 .
[0056] Fourth embodiment of silica gel dehumidifying bed and its preparation method:
[0057] As an explanation of the fourth embodiment of the silica gel dehumidifying bed and its preparation method of the present invention, the following description only focuses on the differences from the third embodiment of the silica gel dehumidifying bed and its preparation method described above.
[0058] In this embodiment, the hygroscopic salt in step ten is lithium chloride, and the hydrolysis solution contains 80% water and 20% lithium chloride by mass. The resulting silica gel coating density on the silica gel dehumidification bed is 0.29 kg / m³. 2 .
[0059] Performance testing
[0060] Dehumidification tests were conducted on Examples 1 to 4. The only difference between the examples was the method for preparing the dehumidification bed; all other test conditions were the same. Samples from Examples 1 to 4 were cut into 200*70*30mm blocks, and their dehumidification performance was tested under the following conditions: temperature 26℃, relative humidity 40%. The test method is as follows:
[0061] 1. Place the sample in the desorption device and desorb until it no longer loses weight;
[0062] 2. Place the completely desorbed sample into the test chamber and allow it to naturally adsorb under the above environmental conditions until saturation. Test the dehumidification performance of the sample under complete desorption conditions.
[0063] The dehumidification performance of the silica gel dehumidification beds obtained in Examples 1 to 4 under complete desorption conditions is shown in Table 1.
[0064] Table 1
[0065]
[0066] Furthermore, under the same testing conditions as in the embodiments, the dehumidification capacity (g / kg - moisture absorption / weight gain per kilogram) of ordinary silica gel dehumidifying beds was measured to be approximately 80 g / kg to 120 g / kg. The preparation methods of the embodiments in this invention can improve the dehumidification effect of the dehumidifying bed.
[0067] As shown in the table above, compared with Examples 1 and 2, reducing the mesh size of the silica gel particles initially attached significantly improves the dehumidification capacity of the dehumidification bed. Comparing Examples 3 and 4, the dehumidification depth varies depending on the hygroscopic salt used; lithium chloride salt exhibits significantly higher hygroscopicity than potassium formate salt. Furthermore, actual usage verification shows that the dehumidification effect and service life of the dehumidification beds obtained in Examples 1 to 4 are superior to ordinary silica gel dehumidification beds. This is because impregnating the dehumidification bed substrate with silica gel solution increases the specific surface area and allows it to firmly adhere to the surface of the silica gel particles, forming a silicon-oxygen bond between the particles, thus adhering the silica gel particles to the metal-based honeycomb plate and improving the adhesion of the silica gel particles.
[0068] As can be seen from the above, after laying the silica powder layer and drying and curing it, immersing the dehumidifying bed substrate in the silica solution increases the specific surface area. Simultaneously, the colloidal particles firmly adhere to the surface of the silica particles on the dried and cured dehumidifying bed substrate, forming silicon-oxygen bonds between the particles, thus firmly adhering the silica particles to the dehumidifying bed substrate and significantly improving the adhesion of the silica particles. Furthermore, by laying two silica powders of different particle sizes, the smaller silica powder can fill the gaps between the larger silica powder particles, further increasing the coating density of the silica on the dehumidifying bed substrate, thereby improving the moisture absorption performance. In addition, immersing the dehumidifying bed substrate with attached silica particles in a hydrolyzed solution of hygroscopic salts further enhances the moisture absorption performance of the coating. Lithium chloride salts have excellent hygroscopic properties, ensuring greater dehumidification capacity under the same thickness of silica coating. Therefore, the silica dehumidifying bed prepared by this method not only effectively reduces the number of silica particles detaching, minimizing the loss of dehumidification performance, but also increases the silica coating density without causing blockage of the dehumidifying bed pores, thereby improving the dehumidification capacity of the dehumidifying bed.
[0069] Finally, it should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a silica gel dehumidifying bed, characterized in that, include: Step 1: Immerse the dehumidifying bed substrate in the viscous emulsion; Step 2: Distribute the first type of silica gel powder onto the dehumidifying bed substrate impregnated with the viscous emulsion obtained in Step 1; Step 3: Dry and cure the dehumidification bed substrate with the silicone powder layer laid on it; Step 4: Immerse the dried and cured dehumidified bed substrate in the silica gel solution; Step 5: Dry and cure the dehumidifying bed substrate impregnated with silica gel solution obtained in Step 4. Step six: Immerse the dehumidifying bed substrate with a silica gel layer obtained in step five in a hydrolysis solution of hygroscopic salts; Step 7: Dry the impregnated dehumidifying bed substrate obtained in Step 6 to obtain the silica gel dehumidifying bed; Between step two and step three, the preparation method further includes a step of laying a second type of silica powder; The step of laying the second type of silica powder is as follows: the second type of silica powder is spread on the dehumidification bed substrate with the first type of silica powder attached obtained in step two, and the mesh size of the second type of silica powder is greater than that of the first type of silica powder.
2. The preparation method according to claim 1, characterized in that: The first type of silica gel powder has a mesh size in the range of 20 to 100 mesh; and / or The mesh size of the second type of silica powder is in the range of 120 mesh to 300 mesh.
3. The preparation method according to claim 1, characterized in that: Before step six, steps four and five shall be repeated at least once.
4. The preparation method according to any one of claims 1 to 3, characterized in that: The hygroscopic salt is at least one of lithium chloride and potassium formate, and / or The hygroscopic salt has a mass fraction of 5% to 30%.
5. The preparation method according to any one of claims 1 to 3, characterized in that: In step one, the dehumidifying bed substrate is immersed in the viscous emulsion for a period ranging from 1 minute to 60 minutes; and / or In step four, the dried and cured dehumidifying bed substrate is immersed in the silica gel solution for a period ranging from 0.5 hours to 3 hours; and / or In steps three and five, the drying temperature of at least one is in the range of 80°C to 120°C, and the drying time of at least one is in the range of 1 hour to 6 hours.
6. The preparation method according to any one of claims 1 to 3, characterized in that: The viscous emulsion is an aqueous acrylic resin emulsion; and / or The concentration of the silica gel solution is 20% to 40%.
7. The preparation method according to any one of claims 1 to 3, characterized in that: Prior to step one, the preparation method further includes a pretreatment step for the dehumidification bed substrate; In the pretreatment step, the dehumidification bed substrate is first immersed in sodium hydroxide solution to remove grease and impurities, and then cleaned with water and ethanol.
8. A silica gel dehumidifying bed, characterized in that, The silica gel dehumidification bed is manufactured by the preparation method described in any one of claims 1 to 7; The silica gel dehumidification bed includes a dehumidification bed substrate and a dehumidifying agent disposed on the surface of the dehumidification bed substrate.