Molecular sieve with high water absorption capacity for automobile air conditioner radiator and preparation method of molecular sieve
High water absorption molecular sieves were prepared by blending a two-component binder with carbon nanofibers and then subjecting them to plasma bombardment treatment. This solved the contradiction between mechanical strength and porosity, and enabled efficient water adsorption and improved stability of air conditioning systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-13
- Publication Date
- 2026-03-13
AI Technical Summary
Traditional molecular sieve molding processes struggle to balance mechanical strength and porosity, and existing improvement schemes fail to significantly enhance overall performance, resulting in poor moisture adsorption in air conditioning systems and impacting service life.
A high water absorption molecular sieve was prepared by blending a two-component binder with carbon nanofibers and potassium salts, followed by calcination and plasma bombardment to form a multi-level pore structure and a nanoscale molten layer, thereby enhancing mechanical stability and porosity.
A stable and high-strength structure of high water absorption molecular sieve has been achieved, which can effectively adsorb moisture in automotive air conditioning systems, avoid ice blockage and corrosion, and extend the service life of air conditioning systems.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] This application relates to the technical field of air conditioning components, and in particular to a high water absorption molecular sieve for automotive air conditioning radiators and its preparation method. Background Technology
[0002] Moisture is the number one enemy of automotive air conditioning systems. At the expansion valve (or throttling pipe), the liquid refrigerant rapidly evaporates and absorbs heat, reaching extremely low temperatures. If water is present in the system, it will freeze at this point, clogging the pipes and causing the air conditioning to stop cooling altogether. When water mixes with refrigerant (especially R134a), it can produce hydrochloric acid and hydrofluoric acid under the catalysis of metals, severely corroding aluminum components (such as evaporators and condensers) and copper pipes in the air conditioning system, leading to system leaks and failure. Moisture can also cause a "copper plating" phenomenon, where copper ions deposit on the surface of steel components (such as compressor pistons and bearings), damaging their smoothness and clearances, ultimately causing the compressor to seize up or wear out. To solve the problem of residual moisture, technicians have added molecular sieves to the air conditioning components, effectively adsorbing moisture in the automotive air conditioning system, avoiding the aforementioned quality hazards, and significantly extending the lifespan of the automotive air conditioning radiator.
[0003] However, in the traditional industrial molding process of molecular sieves, it is difficult to balance the mechanical strength and porosity of the molecular sieve molded body. Existing attempts usually focus on improving a single binder or optimizing calcination conditions, but these solutions often cannot fundamentally solve the contradiction between mechanical strength and porosity, and have limited protective effect on the molecular sieve structure, resulting in no significant improvement in the overall performance of the molded body. Summary of the Invention
[0004] To address the aforementioned technical problems, this application provides a high water absorption molecular sieve for automotive air conditioning radiators and its preparation method.
[0005] In a first aspect, this application provides a method for preparing a high water absorption molecular sieve for automotive air conditioning radiators, comprising the following steps: S1. Preparation of a two-component adhesive; S2. Granulation: Molecular sieve raw powder, carbon nanofibers and potassium salt are blended in a weight ratio of 65:(0.5-0.7):(4-5), and then the two-component binder is injected into the blend. The weight ratio of molecular sieve raw powder to two-component binder is controlled to be 65:(20-24). Granulation and drying are performed to obtain semi-finished granules. The molecular sieve raw powder is 4A molecular sieve raw powder. S3. Calcination: Calcinate the semi-finished granules at a temperature of 550-600℃ for 100-150 minutes; S4. Strengthening: After cooling the particles obtained in S3 to 220-280℃, place them in a vacuum system and introduce inert gas at a flow rate of 30-50 sccm. Keep them at the temperature, and then bombard the particles with plasma at a radio frequency power of 50-150W for 10-30 minutes. After cooling and depressurization, a high water absorption molecular sieve with a particle size of 1.6-2.5 mm is obtained.
[0006] By adopting the above technical solution, this application first prepared a two-component binder, and then pre-blended molecular sieve powder, carbon nanofibers, and potassium salt to obtain a blend. The carbon nanofibers can form a stable mechanical structure during calcination, thereby enhancing the mechanical stability of the material. The two-component binder was added to the system by injection, granulation, and then calcination, and the molecular sieve particles were basically formed. At this time, the molecular sieve already had a multi-level pore structure, with high compressive strength and porosity. Subsequently, this application subjected it to plasma bombardment treatment to form a nanoscale molten layer on the surface of the molecular sieve, eliminating micro-cracks without clogging the pores, fundamentally solving the contradiction between mechanical strength and porosity. The resulting high water absorption molecular sieve has a potassium exchange rate ≤38%, a crushing force ≥75N, and a static water adsorption capacity between 17% and 22% under RH 75% conditions.
[0007] Preferably, the specific operation of S1 is as follows: S11. Tetraethyl silicate and PVA are mixed in a weight ratio of (2-3):10 and reacted at pH=2-5 and temperature of 50-70℃ for 4-10 hours. After standing and aging, component A is obtained. S12. Diammonium hydrogen phosphate and aluminum nitrate were mixed and reacted at pH 3-4 to obtain aluminum phosphate sol. Then, aluminum phosphate sol was mixed with nanocellulose at a mass ratio of (1-3):1 to obtain component B. S13. Dispense component A and component B in a weight ratio of (6-8):(2-4) to obtain a two-component adhesive.
[0008] Preferably, the weight ratio of component A to component B is 7:3.
[0009] By adopting the above technical solutions, this application utilizes the hydrolysis of tetraethyl silicate under acidic conditions to generate silica sol, which is then blended with PVA to form a nanocomposite network structure. The hydroxyl groups of PVA and the silanol groups of the silica sol form hydrogen bonds, enhancing interfacial bonding, resulting in component A, which provides greater initial adhesion during granulation. This application also utilizes the colloidal stability of aluminum phosphate under acidic conditions, combining it with nanocellulose through electrostatic interaction to form a highly dispersed suspension, which can form a ceramic-phase reinforced structure during calcination. Finally, this application packages components A and B in a weight ratio of (6-8):(2-4) to obtain a two-component binder, resolving the contradiction between high strength and high porosity that a single binder cannot simultaneously achieve in molecular sieve molding. The two-component binder of this application can achieve rapid gelation after injection into the system, achieving basic fixation of the material. Subsequently, during the heating and calcination process, it triggers an aluminum phosphate ceramicization reaction, forming a gradient solidification structure from the outside to the inside. Combined with the addition of carbon nanofibers and the strengthening treatment of the molecular sieve in this application, the overall performance of the molecular sieve can be significantly improved.
[0010] Optionally, in S11, the degree of polymerization of PVA is 500, 1700, 2000 or 2400.
[0011] Preferably, in S11, the degree of polymerization of PVA is 1700.
[0012] By adopting the above technical solution, this application controls the degree of polymerization of PVA to 1700, and the resulting component A can more quickly wet the molecular sieve powder and carbon nanofibers to form a stronger initial bonding structure.
[0013] Optionally, in S12, the diameter of the nanocellulose is 5-10 nm, 10-15 mm, or 15-20 mm. Preferably, in S12, the diameter of the nanocellulose is 5-10 nm.
[0014] By adopting the above technical solution, this application controls the diameter of nanocellulose to be 5-10 nm, which enables it to recombine with aluminum phosphate sol more quickly, forming a highly dispersed suspension with better internal uniformity. During the calcination process, it can form a ceramic phase-reinforced structure with more uniform distribution and more stable structure.
[0015] Preferably, in S2, the potassium salt comprises potassium chloride and potassium silicate in a weight ratio of 3:(1-2).
[0016] Preferably, in step S2, the weight ratio of molecular sieve powder, two-component binder, carbon nanofibers and potassium salt is 65:22:0.6:4.8.
[0017] Preferably, in step S4, an inert gas is introduced at a flow rate of 45 sccm.
[0018] Preferably, in step S4, the radio frequency power is 100W.
[0019] Secondly, this application also provides a method for preparing the above-mentioned high water absorption molecular sieve for automotive air conditioning radiators, wherein the high water absorption molecular sieve has a potassium exchange rate ≤38%, a static water adsorption capacity ≤22% and a crushing resistance ≥75N.
[0020] By adopting the above technical solution, the high water absorption molecular sieve obtained in this application has a stable and high-strength structure, which can achieve a two-way balance between mechanical strength and porosity. It can adsorb moisture in the automotive air conditioning system in a long-term, stable and effective manner, minimize the occurrence of ice blockage in the internal pipes of the air conditioner, prevent the refrigerant from hydrolyzing and corroding the aluminum evaporator, condenser and copper pipes of the air conditioning system when it comes into contact with water, and also prevent the formation of copper film on the surface of steel components inside the air conditioner, effectively extending the service life of the air conditioner.
[0021] In summary, this application has the following beneficial technical effects: 1. This application first prepared a two-component binder, then pre-blended molecular sieve powder, carbon nanofibers, and potassium salt to obtain a blend. The carbon nanofibers can form a stable mechanical structure during calcination, thereby enhancing the mechanical stability of the material. The two-component binder was added to the system by injection, granulation, and then calcination, resulting in the basic formation of molecular sieve particles. At this point, the molecular sieve already has a multi-level pore structure, with high compressive strength and porosity. Subsequently, this application subjected it to plasma bombardment treatment to form a nanoscale molten layer on the surface of the molecular sieve, eliminating micro-cracks without clogging the pores, fundamentally solving the contradiction between mechanical strength and porosity. The resulting high water absorption molecular sieve has a potassium exchange rate ≤38%, a crushing force ≥75N, and a static water adsorption capacity between 17% and 22% under RH 75% conditions. 2. The two-component binder of this application can achieve rapid gelation after injection into the system, which can basically fix the material. Then, during the heating and calcination process, it will trigger the aluminum phosphate ceramicization reaction to form a gradient solidification structure from the outside to the inside. Combined with the addition of carbon nanofibers and the strengthening treatment of molecular sieves in this application, the comprehensive performance of molecular sieves can be greatly improved. 3. The high water absorption molecular sieve obtained in this application has a stable and high-strength structure, which can achieve a two-way balance between mechanical strength and porosity. It can adsorb moisture in the automotive air conditioning system in a long-term, stable and effective manner, minimize the occurrence of ice blockage in the internal pipes of the air conditioning system, prevent the refrigerant from hydrolyzing and corroding the aluminum evaporator, condenser and copper pipes of the air conditioning system when it comes into contact with water, and also prevent the formation of copper film on the surface of steel components inside the air conditioning system, effectively extending the service life of the air conditioning system. Detailed Implementation
[0022] The present application will be further described in detail below with reference to embodiments and comparative examples.
[0023] Example 1.1 A method for preparing a high water absorption molecular sieve for automotive air conditioning radiators includes the following steps: S1. Preparation of a two-component adhesive: S11. Disperse 100g of PVA-1700 in deionized water at 95℃ to obtain a 10wt% PVA solution. Stir magnetically until the system is transparent. Add 20g of tetraethyl silicate to the system and react for 10h at pH=5 and temperature of 50℃ to form a homogeneous and transparent sol-gel system. Then let it stand for 24h to obtain component A. S12. Disperse 100g of cellulose nanoparticles with a diameter of 5-10mm in water to obtain a suspension with a concentration of 5wt%. Sonicate the suspension for 30min at a power of 300W and set aside. Mix 1mol of diammonium hydrogen phosphate and 1mol of aluminum nitrate nonahydrate and stir for 2h at pH=3 and temperature of 60℃ to obtain aluminum phosphate sol and set aside. Mix the cellulose nanoparticle suspension and aluminum phosphate sol at a mass ratio of aluminum sulfate to cellulose nanoparticles of 1:1, add 0.3wt% triammonium citrate as a dispersant, and stir magnetically for 4h to obtain component B. S13. Dispense component A and component B in a weight ratio of 6:4 to obtain a two-component adhesive; S2. Granulation: Mix 650g of molecular sieve raw powder, 5g of carbon nanofiber and 50g of potassium salt (30g of potassium chloride and 20g of potassium silicate), stir evenly and then use a dual-channel micro-injection pump to inject 200g of two-component binder into the powder. When injecting, component A and component B are injected separately. Granulate and then dry at 150℃ for 2 hours to obtain semi-finished granules. S3. Calcination: Place the semi-finished granules in a muffle furnace and calcine at 600℃ for 100 minutes; S4. Enhancement: After cooling the particles obtained in S3 to 280℃, place them in a vacuum system and introduce nitrogen gas at a flow rate of 50 sccm. Keep the temperature, then bombard the particles with Ar plasma at a radio frequency power of 150W for 10 minutes. After cooling and depressurization, a high water absorption molecular sieve with a particle size of 1.6-2.5 mm is obtained.
[0024] Example 1.2 A method for preparing a high water absorption molecular sieve for automotive air conditioning radiators includes the following steps: S1. Preparation of a two-component adhesive: S11. Disperse 100g of PVA-1700 in deionized water at 95℃ to obtain a 10wt% PVA solution. Stir magnetically until the system is transparent. Add 30g of tetraethyl silicate to the system and react for 4h at pH=2 and temperature of 70℃ to form a homogeneous and transparent sol-gel system. Then let it stand for 24h to obtain component A. S12. Disperse 100g of cellulose nanoparticles with a diameter of 5-10mm in water to obtain a suspension with a concentration of 5wt%. Sonicate the suspension for 30min at a power of 300W and set aside. Mix 1mol of diammonium hydrogen phosphate and 1mol of aluminum nitrate nonahydrate and stir for 2h at pH=4 and temperature of 60℃ to obtain aluminum phosphate sol and set aside. Mix the cellulose nanoparticle suspension and aluminum phosphate sol at a mass ratio of aluminum sulfate to cellulose nanoparticles of 3:1, add 0.3wt% triammonium citrate as a dispersant, and stir magnetically for 4h to obtain component B. S13. Dispense component A and component B in a weight ratio of 8:2 to obtain a two-component adhesive; S2. Granulation: 650g of molecular sieve raw powder, 7g of carbon nanofibers and 40g of potassium salt (30g of potassium chloride and 10g of potassium silicate) are mixed and stirred evenly. Then, 240g of two-component binder is injected into the powder using a dual-channel micro-injection pump. Component A and component B are injected separately during injection. Granulation is then carried out, and the powder is dried at 150℃ for 2 hours to obtain semi-finished granules. S3. Calcination: Place the semi-finished granules in a muffle furnace and calcine at 550℃ for 150 minutes; S4. Enhancement: After cooling the particles obtained in S3 to 220℃, place them in a vacuum system and introduce nitrogen gas at a flow rate of 30 sccm. Keep the temperature, then bombard the particles with Ar plasma at a radio frequency power of 50W for 30 minutes. After cooling and depressurization, a high water absorption molecular sieve with a particle size of 1.6-2.5 mm is obtained.
[0025] Example 1.3 A method for preparing a high water absorption molecular sieve for automotive air conditioning radiators includes the following steps: S1. Preparation of a two-component adhesive: S11. Disperse 100g of PVA-1700 in deionized water at 95℃ to obtain a 10wt% PVA solution. Stir magnetically until the system is transparent. Add 25g of tetraethyl silicate to the system and react for 7h at pH=3.5 and temperature of 50℃ to form a homogeneous and transparent sol-gel system. Then let it stand for 24h to obtain component A. S12. Disperse 100g of cellulose nanoparticles with a diameter of 5-10mm in water to obtain a suspension with a concentration of 5wt%. Sonicate the suspension for 30min at a power of 300W and set aside. Mix 1mol of diammonium hydrogen phosphate and 1mol of aluminum nitrate nonahydrate and stir for 2h at pH=3.5 and temperature of 60℃ to obtain aluminum phosphate sol and set aside. Mix the cellulose nanoparticle suspension and aluminum phosphate sol at a mass ratio of aluminum sulfate to cellulose nanoparticles of 2:1, add 0.3wt% triammonium citrate as a dispersant, and stir magnetically for 4h to obtain component B. S13. Dispense component A and component B in a weight ratio of 7:3 to obtain a two-component adhesive; S2. Granulation: 650g of molecular sieve raw powder, 6g of carbon nanofiber and 48g of potassium salt (28.8g of potassium chloride and 19.2g of potassium silicate) are mixed and stirred evenly. Then, 220g of two-component binder is injected into the powder using a dual-channel micro-injection pump. Component A and component B are injected separately during injection. Granulation is then carried out, and the powder is dried at 150℃ for 2 hours to obtain semi-finished granules. S3. Calcination: Place the semi-finished granules in a muffle furnace and calcine at 575℃ for 125 minutes; S4. Enhancement: After cooling the particles obtained in S3 to 250°C, place them in a vacuum system and introduce nitrogen gas at a flow rate of 45 sccm. Keep the temperature, then bombard the particles with Ar plasma at a radio frequency power of 100W for 20 minutes. After cooling and depressurization, a high water absorption molecular sieve with a particle size of 1.6-2.5 mm is obtained.
[0026] Example 2.1 A method for preparing a high water absorption molecular sieve for automotive air conditioning radiators differs from Example 1.3 in that, in S11, PVA-1700 is replaced with PVA-500, while the rest is the same as in Example 1.3.
[0027] Example 2.2 A method for preparing a high water absorption molecular sieve for automotive air conditioning radiators differs from Example 1.3 in that, in S11, PVA-1700 is replaced with PVA-2000, while the rest is the same as in Example 1.3.
[0028] Example 2.3 A method for preparing a high water absorption molecular sieve for automotive air conditioning radiators differs from Example 1.3 in that, in S11, PVA-1700 is replaced with PVA-2400, while the rest is the same as in Example 1.3.
[0029] Example 3.1 A method for preparing a high water absorption molecular sieve for automotive air conditioning radiators differs from Example 1.3 in that, in S12, nanocellulose with a diameter of 5-10 nm is replaced with nanocellulose with a diameter of 10-15 mm, while the rest is the same as in Example 1.3.
[0030] Example 3.2 A method for preparing a high water absorption molecular sieve for automotive air conditioning radiators differs from Example 1.3 in that, in S12, nanocellulose with a diameter of 5-10 nm is replaced with nanocellulose with a diameter of 15-20 mm, while the rest is the same as in Example 1.3.
[0031] Example 4.1 A method for preparing a high water absorption molecular sieve for automotive air conditioning radiators differs from Example 1.3 in that, in S2, the potassium salt includes 28.8g of potassium chloride and 19.2g of potassium carbonate, while the rest are the same as in Example 1.3.
[0032] Example 4.2 A method for preparing a high water absorption molecular sieve for automotive air conditioning radiators differs from Example 1.3 in that, in S2, the potassium salt includes 28.8g of potassium sulfate and 19.2g of potassium silicate, while the rest are the same as in Example 1.3.
[0033] Example 4.3 A method for preparing a high water absorption molecular sieve for automotive air conditioning radiators differs from Example 1.3 in that, in S2, the potassium salt includes 28.8g of potassium carbonate and 19.2g of potassium silicate, while the rest are the same as in Example 1.3.
[0034] Comparative Example 1 Includes the following steps: S1. Granulation: Mix 650g of molecular sieve raw powder, 200g of kaolin clay and 50g of potassium salt (30g of potassium chloride and 20g of potassium silicate), spray water in a water chestnut pot to granulate, and then dry at 150℃ for 2 hours to obtain semi-finished granules. S2. Calcination: The semi-finished particles are placed in a muffle furnace and calcined at 600℃ for 100 minutes to obtain a high water absorption molecular sieve with a particle size of 1.6-2.5mm.
[0035] Comparative Example 2.1 Includes the following steps: S1. Granulation: 650g of molecular sieve raw powder, 5g of carbon nanofiber, 200g of kaolin clay and 50g of potassium salt (30g of potassium chloride and 20g of potassium silicate) are mixed together, water is sprayed in a water chestnut pot to granulate, and then dried at 150℃ for 2 hours to obtain semi-finished granules. S2. Calcination: The semi-finished particles are placed in a muffle furnace and calcined at 600℃ for 100 minutes to obtain a high water absorption molecular sieve with a particle size of 1.6-2.5mm.
[0036] Comparative Example 2.2 The difference from Example 1.1 is that 5g of carbon nanofibers were removed, while the rest were the same as in Example 1.1.
[0037] Comparative Example 3.1 Includes the following steps: S1. Granulation: 650g of molecular sieve raw powder, 5g of carbon nanofiber, 200g of kaolin clay and 50g of potassium salt (30g of potassium chloride and 20g of potassium silicate) are mixed together, water is sprayed in a water chestnut pot to granulate, and then dried at 150℃ for 2 hours to obtain semi-finished granules. S2. Calcination: Place the semi-finished granules in a muffle furnace and calcine at 600℃ for 100 minutes; S3. Enhancement: After cooling the particles obtained in S2 to 280℃, place them in a vacuum system and introduce nitrogen gas at a flow rate of 50 sccm. Keep the temperature, then bombard the particles with Ar plasma at a radio frequency power of 150W for 10 minutes. After cooling and depressurization, a high water absorption molecular sieve with a particle size of 1.6-2.5 mm is obtained.
[0038] Comparative Example 3.2 Includes the following steps: S1. Preparation of adhesive: 100g PVA-1700 was dispersed in deionized water at 95℃ to obtain a 10wt% PVA solution. The solution was magnetically stirred until the system was transparent. 20g tetraethyl silicate was added to the system and reacted at pH=5 and temperature of 50℃ for 10h to form a homogeneous and transparent sol-gel system. The system was then allowed to stand for 24h to mature, and the adhesive was obtained. S2. Granulation: Mix 65g of molecular sieve raw powder, 0.5g of nano carbon fiber and 5g of potassium salt (3g of potassium chloride and 2g of potassium silicate), stir evenly and then use a micro injection pump to inject 20g of binder into the powder to granulate. Then dry at 150℃ for 2 hours to obtain semi-finished granules. S3. Calcination: Place the semi-finished granules in a muffle furnace and calcine at 600℃ for 100 minutes; S4. Enhancement: After cooling the particles obtained in S3 to 280℃, place them in a vacuum system and introduce nitrogen gas at a flow rate of 50 sccm. Keep the temperature, then bombard the particles with Ar plasma at a radio frequency power of 150W for 10 minutes. After cooling and depressurization, a high water absorption molecular sieve with a particle size of 1.6-2.5 mm is obtained.
[0039] Comparative Example 3.3 Includes the following steps: S1. Preparation of binder: 100g of nanocellulose with a diameter of 5-10mm was dispersed in water to obtain a suspension with a concentration of 5wt%. The suspension was ultrasonically treated for 30min at a power of 300W and set aside. 1mol of diammonium hydrogen phosphate and 1mol of aluminum nitrate nonahydrate were mixed and stirred for 2h at pH=3 and temperature of 60℃ to obtain aluminum phosphate sol and set aside. The nanocellulose suspension and aluminum phosphate sol were mixed at a mass ratio of aluminum sulfate to nanocellulose of 1:1. 0.3wt% triammonium citrate was added as a dispersant and the mixture was magnetically stirred for 4h to obtain the binder. S2. Granulation: Mix 65g of molecular sieve raw powder, 0.5g of nano carbon fiber and 5g of potassium salt (3g of potassium chloride and 2g of potassium silicate), stir evenly and then use a micro injection pump to inject 20g of binder into the powder to granulate. Then dry at 150℃ for 2 hours to obtain semi-finished granules. S3. Calcination: Place the semi-finished granules in a muffle furnace and calcine at 600℃ for 100 minutes; S4. Enhancement: After cooling the particles obtained in S3 to 280℃, place them in a vacuum system and introduce nitrogen gas at a flow rate of 50 sccm. Keep the temperature, then bombard the particles with Ar plasma at a radio frequency power of 150W for 10 minutes. After cooling and depressurization, a high water absorption molecular sieve with a particle size of 1.6-2.5 mm is obtained.
[0040] Comparative Example 4.1 Includes the following steps: S1. Granulation: Mix 650g of molecular sieve raw powder, 200g of kaolin clay and 50g of potassium salt (30g of potassium chloride and 20g of potassium silicate), spray water in a water chestnut pot to granulate, and then dry at 150℃ for 2 hours to obtain semi-finished granules. S2. Calcination: Place the semi-finished granules in a muffle furnace and calcine at 600℃ for 100 minutes; S3. Enhancement: After cooling the particles obtained in S2 to 280℃, place them in a vacuum system and introduce nitrogen gas at a flow rate of 50 sccm. Keep the temperature, then bombard the particles with Ar plasma at a radio frequency power of 150W for 10 minutes. After cooling and depressurization, a high water absorption molecular sieve with a particle size of 1.6-2.5 mm is obtained.
[0041] Comparative Example 4.2 Includes the following steps: S1. Granulation: 650g of molecular sieve raw powder, 5g of carbon nanofiber, 200g of kaolin clay and 50g of potassium salt (30g of potassium chloride and 20g of potassium silicate) are mixed together, water is sprayed in a water chestnut pot to granulate, and then dried at 150℃ for 2 hours to obtain semi-finished granules. S2. Calcination: Place the semi-finished granules in a muffle furnace and calcine at 600℃ for 100 minutes; S3. Enhancement: After cooling the particles obtained in S2 to 280℃, place them in a vacuum system and introduce nitrogen gas at a flow rate of 50 sccm. Keep the temperature, then bombard the particles with Ar plasma at a radio frequency power of 150W for 10 minutes. After cooling and depressurization, a high water absorption molecular sieve with a particle size of 1.6-2.5 mm is obtained.
[0042] Comparative Example 4.3 The difference from Example 1.1 is that S4 is removed, and the rest is the same as Example 1.1.
[0043] Performance testing
[0044] The high water absorption capacity molecular sieves with a particle size of 1.6-2.5 mm obtained in the examples and comparative examples were tested for static water adsorption capacity [75%RH, (35±1)℃] / % and crushing force / N.
[0045] Table 1 Data Record Table
[0046] Data Analysis: As can be seen from Table 1, the high water absorption molecular sieve obtained in this application has a potassium exchange rate ≤38%, a static water adsorption capacity ≤22% (17%), and a crushing force ≥75N. In contrast, the molecular sieve of Comparative Example 1 has a static water adsorption capacity of only 16.2% and a crushing force of only 36.5N. It is evident that the preparation method of this application fundamentally solves the contradiction between mechanical strength and porosity. The obtained high water absorption molecular sieve can adsorb moisture in automotive air conditioning systems in a long-term, stable, and effective manner, avoiding phenomena such as ice blockage and pipe corrosion, and can effectively extend the service life of automotive air conditioning systems.
[0047] In Comparative Example 2.1, this application added carbon nanofibers to Comparative Example 1. In Comparative Example 2.2, this application removed carbon nanofibers from Comparative Example 1.1. Adding carbon nanofibers to Comparative Example 1 can increase the crushing resistance by 14.9%, while adding carbon nanofibers to Comparative Example 2.2 can increase the crushing resistance by 24.3%. It can be seen that there is a synergistic effect between the steps of this application. The two-component binder, the addition of carbon nanofibers, and the strengthening treatment of molecular sieve can work together to improve the comprehensive performance of molecular sieve.
[0048] In Comparative Example 3.1, this application replaced the two-component binder with ordinary kaolin clay. The results showed that even with the strengthening step, the crushing resistance of the molecular sieve could only reach 47.4 N. This indicates that the two-component binder of this application can achieve rapid gelation after injection into the system, thus achieving basic fixation of the material. Subsequently, during the heating and calcination process, it will trigger the aluminum phosphate ceramicization reaction, forming a gradient solidification structure from the outside to the inside. Combined with the addition of carbon nanofibers and the strengthening treatment of the molecular sieve in this application, the comprehensive performance of the molecular sieve can be greatly improved.
[0049] In Comparative Examples 3.2-3.3, this application replaced the two-component binder with a single-component binder. The results showed that even with the reinforcement step, the crushing resistance of the molecular sieve could only reach 53.1-54.3 N. This indicates that component A provides greater initial binding force during granulation, while component B can form a ceramic phase reinforcement structure during calcination. Both are indispensable and can only achieve a significant improvement in the performance of the molecular sieve by working together.
[0050] In Comparative Example 4.1, this application adds a strengthening treatment based on Comparative Example 1, resulting in a 20.1% relative increase in crushing resistance. In Comparative Example 4.2, this application adds a strengthening treatment based on Comparative Example 2.1, resulting in a 29.1% relative increase in crushing resistance. Example 1.1 is equivalent to adding a strengthening treatment based on Comparative Example 4.3, resulting in a 40.1% relative increase in crushing resistance. It can be seen that there is a synergistic effect between the various steps of this application. The operation of two-component binder, adding carbon nanofibers and strengthening the molecular sieve can work together to improve the overall performance of the molecular sieve.
[0051] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. A method for preparing a high water absorption molecular sieve for automotive air conditioning radiators, characterized in that, Includes the following steps: S1. Preparation of a two-component adhesive; S2. Granulation: Molecular sieve raw powder, carbon nanofiber and potassium salt are blended in a weight ratio of 65:(0.5-0.7):(4-5), and then the two-component binder is injected into the above blend. The weight ratio of molecular sieve raw powder and two-component binder is controlled to be 65:(20-24). Granulation and drying are performed to obtain semi-finished granules. S3. Calcination: Calcinate the semi-finished granules at a temperature of 550-600℃ for 100-150 minutes; S4. Strengthening: After cooling the particles obtained in S3 to 220-280℃, place them in a vacuum system and introduce inert gas at a flow rate of 30-50 sccm. Keep them at the temperature, and then bombard the particles with plasma at a radio frequency power of 50-150W for 10-30 minutes. After cooling and depressurization, a high water absorption molecular sieve with a particle size of 1.6-2.5 mm is obtained.
2. The method for preparing a high water absorption molecular sieve for automotive air conditioning radiators according to claim 1, characterized in that, The specific operation of S1 is as follows: S11. Tetraethyl silicate and PVA are mixed in a weight ratio of (2-3):10 and reacted at pH=2-5 and temperature of 50-70℃ for 4-10 hours. After standing and aging, component A is obtained. S12. Diammonium hydrogen phosphate and aluminum nitrate were mixed and reacted at pH 3-4 to obtain aluminum phosphate sol. Then, aluminum phosphate sol was mixed with nanocellulose at a mass ratio of (1-3):1 to obtain component B. S13. Dispense component A and component B in a weight ratio of (6-8):(2-4) to obtain a two-component adhesive.
3. The method for preparing a high water absorption molecular sieve for an automotive air conditioning radiator according to claim 2, characterized in that, The weight ratio of component A to component B is 7:
3.
4. The method for preparing a high water absorption molecular sieve for an automotive air conditioning radiator according to claim 2, characterized in that, In S11, the degree of polymerization of PVA is 1700.
5. The method for preparing a high water absorption molecular sieve for an automotive air conditioning radiator according to claim 2, characterized in that, In S12, the diameter of the nanocellulose is 5-10 nm.
6. The method for preparing a high water absorption molecular sieve for an automotive air conditioning radiator according to claim 1, characterized in that, In S2, the potassium salt comprises potassium chloride and potassium silicate in a weight ratio of 3:(1-2).
7. The method for preparing a high water absorption molecular sieve for an automotive air conditioning radiator according to claim 1, characterized in that, In S2, the weight ratio of molecular sieve powder, two-component binder, carbon nanofibers and potassium salt is 65:22:0.6:4.
8.
8. The method for preparing a high water absorption molecular sieve for an automotive air conditioning radiator according to claim 1, characterized in that, In step S4, an inert gas is introduced at a flow rate of 45 sccm.
9. The method for preparing a high water absorption molecular sieve for an automotive air conditioning radiator according to claim 1, characterized in that, In S4, the radio frequency power is 100W.
10. A high water absorption molecular sieve obtained by the preparation method of the high water absorption molecular sieve for automotive air conditioning radiators according to any one of claims 1-9, characterized in that, The high water absorption molecular sieve has a potassium exchange rate of ≤38%, a static water adsorption capacity of 17% ≤22%, and a crushing resistance of ≥75N.