A rare earth water-based environmentally friendly urea crystal remover for vehicles and its preparation method

Abstract

This invention relates to the field of special agents for treating air pollution, specifically to a rare earth water-based environmentally friendly urea crystal remover for vehicles and its preparation method. The raw materials for preparing the rare earth water-based environmentally friendly urea crystal remover for vehicles, by weight, include: 0.005-0.2 parts rare earth-based catalyst, 3-10 parts surfactant, 1-3 parts dispersant, 5-10 parts stabilizer, and 80-100 parts deionized water; wherein the rare earth-based catalyst includes at least a cerium-based catalyst. The urea crystal remover provided by this invention has excellent performance, effectively removing urea crystals, and the cerium emission concentration is far below the requirements of the EURO 7 draft (EURO 7 does not require cerium). NOx conversion rate is significantly improved, making it more suitable for vehicles using high-sulfur fuels, and greatly benefiting the control of air pollution from mobile sources. It is also environmentally safe and environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of special agents for treating air pollution, specifically to a rare earth water-based environmentally friendly urea crystal remover for vehicles and its preparation method. Background Technology

[0002] In the current booming automotive industry, while diesel and gasoline vehicles bring convenience to people's travel and freight transportation, they also cause serious environmental and health problems. During vehicle operation, substances such as nitrogen oxides (NOx) are produced. x Harmful gases such as acetaminophen and acetaminophen are emitted into the atmosphere. These gases, once released, severely damage the atmospheric environment and pose a significant threat to human health, easily inducing respiratory diseases and endangering people's lives and health.

[0003] With increasing global environmental awareness and increasingly stringent environmental regulations, diesel vehicles must meet more stringent emission standards. To comply with these standards, regulations mandate the use of urea, such as the urea solution AUS32. Selective catalytic reduction (SCR) technology plays a crucial role in this exhaust gas treatment process. Within the SCR catalytic system, the urea solution AUS32 is precisely injected into the exhaust aftertreatment device, where it rapidly decomposes into ammonia under high temperature. Subsequently, under the catalytic action of a metal-based catalyst, the ammonia reacts with nitrogen oxides in the exhaust gas in a redox reaction, ultimately converting into harmless nitrogen and water before being discharged, thus significantly reducing NOx levels in the exhaust. x The content of [specific substances] makes vehicle emissions more environmentally friendly and compliant with regulations and standards.

[0004] However, in practical applications, adding urea solution AUS32 has also brought a series of new technical problems. The composition of urea solution AUS32, by mass percentage, includes 32.5% high-purity automotive urea, 57.5% water, and 10% antifreeze. In the high-temperature environment of the exhaust pipe (140-220℃), the water in the urea solution evaporates rapidly, and the condensation reaction of the urea solution easily forms urea crystals (components: urea, biuret, triuret, etc.). These crystals often appear at critical locations such as the end of the urea injection unit, flanges, and the front end of the SCR catalytic converter in the exhaust pipe, thus clogging the SCR carrier and even the exhaust system, severely impacting engine performance, increasing fuel consumption, reducing power, and drastically increasing carbon emissions. In cold environments, the solute in the urea solution crystallizes due to the low temperature, also producing urea crystals (component: urea). Furthermore, in the low-temperature environment of winter, more than 50% of China V and China VI emission standard vehicles have experienced urea crystallization. Factors such as using inferior diesel fuel, improper exhaust pipe design, and poor maintenance of the SCR catalytic converter can all contribute to urea crystal formation. The presence of urea crystals not only interferes with normal engine operation but also significantly reduces urea utilization, increases fuel consumption, and makes it difficult to meet emissions standards.

[0005] Currently, the industry has adopted various measures to avoid the numerous problems caused by urea crystallization. For example, drivers can have their exhaust systems ultrasonically cleaned or subjected to high-temperature ablation at professional repair shops; regularly inspect and maintain the SCR catalytic converter to ensure the urea pump and filter are functioning properly; vehicle owners can also improve their driving habits, avoiding turning off the main power immediately after the vehicle is turned off to ensure the urea pump is thoroughly emptied; and choosing high-quality urea solutions while avoiding products containing high levels of aldehydes, phosphates, or other impurities is also important. However, considering cost factors, using urea crystal removers is undoubtedly the most economical and quickest method. Nevertheless, existing urea crystal removers still suffer from unsatisfactory effects and poor stability in practical use, failing to effectively meet market demands and lagging far behind world-leading levels.

[0006] Therefore, developing a highly efficient, environmentally friendly, stable, and economical urea crystal remover has become a critical issue that the industry urgently needs to address. In response, the applicant previously filed an invention patent CN119608240A, which disclosed a urea crystal remover. The raw materials, by weight, included: 0.2 parts copper acetate, 4 parts AEO-10, 2 parts MOA3-PK (potassium fatty alcohol polyoxyethylene ether phosphate), 4 parts PEG-400, 0.5 parts isopropanol, 0.5 parts CAB-35, 0.1 parts methylene blue, and 88.7 parts deionized water. The product effectively removes urea crystals. However, the applicant further discovered that excessive use of MOA3-PK or contact with inferior urea AUS32 solution may produce new fatty alcohol polyoxyethylene ether phosphate salt impurities and cause urea crystals to precipitate at the bottom of the vehicle urea tank, which are then easily adsorbed by the urea pump onto the urea filter, causing malfunctions.

[0007] There is an urgent need for a new type of urea crystal remover for vehicles that can effectively remove urea crystals while maintaining high stability and not easily generating new precipitates. This is a key research direction for current technological improvements. Summary of the Invention

[0008] As an implementable example, the first aspect of this application provides a rare earth water-based environmentally friendly automotive urea crystal removal agent, the raw materials for which, by mass parts, include: 0.005-0.2 parts of rare earth-based catalyst, 3-10 parts of surfactant, 1-3 parts of dispersant, 5-10 parts of stabilizer, and 80-100 parts of deionized water; the rare earth-based catalyst includes at least a cerium-based catalyst.

[0009] As an example of an implementable method, the cerium-based catalyst includes one or more of cerium sulfate, cerium nitrate, cerium acetate, or cerium citrate.

[0010] Furthermore, the cerium-based catalyst is cerium citrate.

[0011] In this invention, cerium citrate (Ce(C6H5O7)) is selected as the cerium-based catalyst, which can achieve efficient removal of urea crystals through a multi-dimensional synergistic mechanism. Cerium citrate, through Ce... 3+ / Ce 4+ Redox reactions catalyze the hydrolysis of urea to produce NH3 and CO2, reducing local concentration and inhibiting crystallization. Furthermore, at low temperatures (120℃~220℃), the reaction accelerates the generation of hydroxyl radicals through valence state changes, thereby enhancing activity. Simultaneously, citrate acts as a polydentate ligand, selectively complexing Ca2+. 2+ Mg 2+The presence of impurity ions prevents the crystallization of double salts and stabilizes the dispersion of cerium ions through electrostatic repulsion to avoid low-temperature precipitation. Furthermore, its weakly alkaline nature maintains the urea hydrolysis environment, preventing acidic conditions from poisoning the vanadium-tungsten catalyst in the SCR support. It also synergistically reduces solution surface tension and inhibits crystallization aggregation with components such as AEO-10 ​​and PEG-400. By precisely controlling the cerium content, negative impacts on the original SCR catalyst are avoided, significantly extending the lifespan of the SCR system and improving NO reduction. X With a conversion rate exceeding 10%, it significantly reduces harmful vehicle exhaust emissions, meeting future Euro 7 emission standards. Simultaneously, the extremely low concentration ratio greatly reduces usage costs. Compared to similar European products (Würth Group's Wirkstoff MF987 SCR system urea cleaner), the concentration (1:400) is reduced by 25%, placing it at the highest technological level globally and significantly reducing the risk of mobile air pollution sources contaminating the atmosphere.

[0012] As an example of implementation, the rare earth-based catalysts also include lanthanum-based catalysts.

[0013] Furthermore, the lanthanum-based catalyst includes one or more of lanthanum sulfate, lanthanum nitrate, lanthanum acetate, or lanthanum citrate.

[0014] Furthermore, when the catalyst comprises a cerium-based catalyst and a lanthanum-based catalyst, the mass ratio of the cerium-based catalyst to the lanthanum-based catalyst is 1:(0.05-0.1).

[0015] Furthermore, when the catalyst comprises a cerium-based catalyst and a lanthanum-based catalyst, the mass ratio of the cerium-based catalyst to the lanthanum-based catalyst is 1:0.1.

[0016] Furthermore, the lanthanum-based catalyst is lanthanum acetate.

[0017] While cerium citrate, a single component, can effectively dissolve urea crystals, in actual research and development, the applicant found that excessive use of cerium citrate may lead to cerium ions competing for the active electron sites of the original SCR vanadium-titanium-tungsten catalyst or catalyst molecular sieve, resulting in emissions that fail to meet the China VI emission standards for automobiles and a relatively long effective mileage. Therefore, lanthanum acetate and cerium citrate were chosen to be used in combination at a mass ratio of 1:(0.05-0.1). The introduction of lanthanum acetate forms a bimetallic catalytic system, which optimizes reaction kinetics by adjusting the local electron cloud density, significantly improving the efficiency of hydroxyl radical generation at low temperatures, thereby increasing the urea decomposition rate by 10%-20%. The combination of the two also has a certain synergistic effect. Cerium citrate preferentially adsorbs sulfides in the exhaust gas, reducing their poisoning of the vanadium-tungsten catalyst in the SCR system. Lanthanum acetate further reduces the sulfur deposition rate through its strong sulfur affinity, extending the life of the SCR support and sensor by more than 4,000 hours. The cerium content is controlled at ≤0.01%, which is 0.3 times the safety threshold of the vanadium catalyst, avoiding interference with the original SCR catalytic function. It solves the problem of low-temperature precipitation of the traditional solvent isopropanol, while meeting the China VI / Euro VI emission standards, and even the future Euro VII (draft) standard. Ultimately, it achieves cerium emissions of <0.1mg / km, which is particularly effective for vehicles using high-sulfur fuels.

[0018] As an example of an implementable approach, the surfactant includes fatty alcohol polyoxyethylene ether.

[0019] Furthermore, the fatty alcohol polyoxyethylene ether has an HLB (hydrophilic-lipophilic) value of 12-14.

[0020] Furthermore, the fatty alcohol polyoxyethylene ether is AEO-10, with a hydrophilic-lipophilic value of 12-14.

[0021] In the earlier application CN119608240A, the applicant selected a compound of AEO-10 ​​and MOA-3PK (potassium fatty alcohol polyoxyethylene ether phosphate) and chose isopropanol as the solvent, which can improve the long-term stability of the urea crystal remover. However, when using a compound of AEO-10 ​​and MOA-3PK, encountering inferior urea AUS32 solution, new fatty alcohol polyoxyethylene ether phosphate salt impurities may precipitate and cause urea crystals to precipitate at the bottom of the vehicle urea tank, which are easily adsorbed by the urea pump onto the urea filter screen, causing malfunctions. Therefore, this invention uses a single-component AEO-10 ​​as a surfactant. AEO-10 ​​can significantly reduce the surface tension of the urea solution, promote the uniform spreading of the solution on the surface of the SCR catalyst, and inhibit the aggregation of crystal particles through electrostatic repulsion. In addition, AEO-10 ​​has a cloud point of 60-70℃ and maintains liquid fluidity at a low temperature of -10℃, avoiding the low-temperature precipitation problem of traditional solvents. It also synergistically enhances solution permeability with cerium-based catalysts, improves urea hydrolysis efficiency by reducing solution viscosity, and stabilizes the dispersion of cerium citrate. At the same time, its weak alkalinity inhibits the poisoning of vanadium-tungsten catalysts by acidic substances, extending the SCR support life to more than 24,000 hours, while being less likely to generate new impurities that would affect the normal operation of the SCR system.

[0022] As an example of an implementable method, the stabilizer includes ethylene glycol tert-butyl ether.

[0023] The moderately polar and non-polar groups of ethylene glycol tert-butyl ether can dissolve cerium citrate catalyst to form a homogeneous solution, and synergistically with AEO-10 ​​to reduce the surface tension of urea and enhance the wettability of the SCR catalyst surface in the exhaust pipe. The hydrogen bond network of ether oxygen atoms stabilizes the dispersion of cerium ions, avoiding the low-temperature precipitation problem of traditional solvents such as isopropanol used in the prior application CN119608240A. The ethylene glycol tert-butyl ether accelerates the hydrolysis kinetics of urea in a weakly polar microenvironment, increasing the NH3 generation rate by 10%-20%, while inhibiting the excessive occupation of catalytic active sites by water molecules. Moreover, its biodegradability meets ISO22241-1 and China VI / Euro VI emission standards.

[0024] As an implementable example, the dispersant includes one or more of polyethylene glycol, isopropanol, butanol, ethanol, propylene glycol, and butanediol.

[0025] Furthermore, the dispersant is polyethylene glycol (PEG).

[0026] Furthermore, the polyethylene glycol is PEG-400.

[0027] The second aspect of the present invention provides a method for preparing a rare earth water-based environmentally friendly automotive urea crystal remover, comprising: mixing a rare earth-based catalyst, a surfactant, a dispersant, a stabilizer and deionized water to obtain the rare earth water-based environmentally friendly automotive urea crystal remover.

[0028] Furthermore, the preparation method of the rare earth water-based environmentally friendly automotive urea crystallizer includes:

[0029] S1. Mix the dispersant and deionized water, and stir at 20-30℃ for 5-10 minutes;

[0030] S2. Add the surfactant and stir at 20-30℃ for 30-40 minutes.

[0031] S3. Add stabilizer and stir at 20-30℃ for 5-10 minutes.

[0032] S4. Add rare earth-based catalyst and stir at 20-30℃ for 5-10 minutes to obtain rare earth water-based environmentally friendly automotive urea crystal remover.

[0033] The rare-earth water-based environmentally friendly automotive urea crystal remover prepared by this invention can be used simply by mixing the product with automotive urea solution AUS32 at a mass ratio of 1:(500-600). It is quick and convenient to use, and exhibits excellent urea crystal dissolution effect, effectively extending the operating time of the SCR system. Simultaneously, the extremely low concentration ratio significantly reduces usage costs. Compared to similar European products (1:400), the concentration ratio is reduced by 25%, placing it at the highest technical level globally.

[0034] Beneficial effects

[0035] (I) In this invention, cerium citrate, a rare earth-based catalyst, is selected as one of the raw material components. Under low-temperature conditions, it preferentially initiates the catalysis of AUS32 urea aqueous solution compared to the SCR supported catalyst, significantly improving the utilization rate of urea. Furthermore, the cerium-based catalyst is relatively safe, environmentally friendly, and highly stable. Compared with urea without the rare earth catalyst, the measured urea consumption is reduced by up to 24%.

[0036] (ii) In order to further reduce the effective mileage, this application selects citric acid and lanthanum acetate as a rare earth-based catalyst, and the two work synergistically to further improve the removal effect of urea crystals.

[0037] (III) The present invention selects a single fatty alcohol polyoxyethylene ether AEO-10 ​​as a surfactant, which can improve the long-term stability of the urea crystal removal agent; and since there is no MOA-3PK, the possibility of new impurity precipitation is reduced.

[0038] (iv) The present invention selects PEG-400 as a dispersant and ethylene glycol tert-butyl ether as a stabilizer, which can further improve the product's ablation properties for urea crystals.

[0039] (V) The urea crystal remover prepared by this invention is easy to use. Simply mix the product and urea solution at a volume ratio of 1:(500-600). It does not pollute the environment, has high safety, and its effective range is less than 2500km. It takes effect quickly and has high long-term stability. The entire process from production to use is more environmentally friendly, better protects the SCR carrier, and extends the service life of the SCR carrier.

[0040] (vi) All formulation components in this invention are listed in the ISO 22241-1 licensed list and comply with China GB 29518-2013 certification. The product is suitable for the SCR sensitive catalytic system of China VI / Euro VI diesel vehicles and maintains solution fluidity at -30℃. Attached Figure Description

[0041] Figure 1 This is a schematic diagram illustrating the working principle of the urea crystal remover in Example 1 of this invention.

[0042] Figure 2 This is a schematic diagram of urea crystals without the use of the rare earth water-based environmentally friendly automotive urea crystal remover from Example 1.

[0043] Figure 3 This is a schematic diagram of urea crystals after using the rare earth water-based environmentally friendly automotive urea crystal remover from Example 1.

[0044] Figure 4 The odometer is for a vehicle that has just used urea containing the rare earth water-based environmentally friendly automotive urea crystal remover prepared in Example 1.

[0045] Figure 5 The odometer is reset after using up one barrel of urea containing the rare earth water-based environmentally friendly automotive urea crystal remover prepared in Example 1 (after 10,000 km). Detailed Implementation

[0046] In the following implementation examples:

[0047] PEG-400 was purchased from Jinan Anqi Chemical Co., Ltd.

[0048] AEO-10 ​​was purchased from Shanghai Huijun Chemical Co., Ltd.

[0049] Example 1

[0050] The first aspect of this example provides a rare earth water-based environmentally friendly urea crystal remover for vehicles, the raw materials for which, by mass parts, include: 0.01 parts rare earth-based catalyst, 4 parts surfactant, 3 parts dispersant, 6 parts stabilizer, and 86.99 parts deionized water.

[0051] The rare earth-based catalyst is cerium citrate (CAS No.: 512-24-3).

[0052] The surfactant is AEO-10.

[0053] The dispersant is PEG-400.

[0054] The stabilizer is ethylene glycol tert-butyl ether (CAS No.: 7580-85-0).

[0055] The second aspect of this example provides a method for preparing a rare earth water-based environmentally friendly automotive urea crystallizer remover, including:

[0056] S1. Mix the dispersant and deionized water, and stir at 25°C for 5 minutes.

[0057] S2. Add the surfactant and stir at 25°C for 35 minutes.

[0058] S3. Add the stabilizer and stir at 25°C for 5 minutes.

[0059] S4. Add rare earth-based catalyst and stir at 25°C for 10 minutes to obtain rare earth water-based environmentally friendly automotive urea crystal remover.

[0060] Example 2

[0061] The first aspect of this example provides a rare earth water-based environmentally friendly automotive urea crystal removal agent, the raw materials for which, by mass parts, include: 0.011 parts rare earth-based catalyst, 4 parts surfactant, 3 parts dispersant, 6 parts stabilizer, and 86.989 parts deionized water.

[0062] The rare earth-based catalyst is cerium citrate (CAS No.: 512-24-3) and lanthanum acetate (CAS No.: 100587-90-4); the mass ratio of cerium citrate to lanthanum acetate is 10:1.

[0063] The surfactant is AEO-10.

[0064] The dispersant is PEG-400.

[0065] The stabilizer is ethylene glycol tert-butyl ether (CAS No.: 7580-85-0).

[0066] The second aspect of this example provides a method for preparing a rare earth water-based environmentally friendly automotive urea crystallizer remover, including:

[0067] S1. Mix the dispersant and deionized water, and stir at 25°C for 5 minutes.

[0068] S2. Add the surfactant and stir at 25°C for 35 minutes.

[0069] S3. Add the stabilizer and stir at 25°C for 5 minutes.

[0070] S4. Add rare earth-based catalyst and stir at 25°C for 10 minutes to obtain rare earth water-based environmentally friendly automotive urea crystal remover.

[0071] Comparative Example 1

[0072] The first aspect of this example provides a urea crystal remover for vehicles, the raw materials for which, by mass parts, include: 4 parts surfactant, 3 parts dispersant, 6 parts stabilizer, and 87 parts deionized water.

[0073] The surfactant is AEO-10.

[0074] The dispersant is PEG-400.

[0075] The stabilizer is ethylene glycol tert-butyl ether (CAS No.: 7580-85-0).

[0076] The second aspect of this example provides a method for preparing a urea crystal scavenger for vehicles, including:

[0077] S1. Mix the dispersant and deionized water, and stir at 25°C for 5 minutes.

[0078] S2. Add the surfactant and stir at 25°C for 35 minutes.

[0079] S3. Add stabilizer and stir at 25°C for 5 minutes to obtain automotive urea crystal remover.

[0080] Comparative Example 2

[0081] The first aspect of this example provides a urea crystal remover for vehicles, the raw materials for which, by mass, include: 4 parts surfactant and 96 parts deionized water.

[0082] The surfactant is AEO-10.

[0083] The second aspect of this example provides a method for preparing a urea crystal remover for vehicles, comprising: mixing a surfactant and deionized water and stirring until homogeneous to obtain the urea crystal remover for vehicles.

[0084] Comparative Example 3 (Refer to Example 1 in Invention Patent CN119608240A)

[0085] The first aspect of this example provides a copper-based urea crystal remover for vehicles, the raw materials for which, by mass parts, include: 0.2 parts copper acetate, 4 parts AEO-10, 2 parts MOA-3PK, 4 parts PEG-400, 0.5 parts isopropanol, 0.5 parts CAB-35 (cocamidopropyl betaine), 0.1 parts methylene blue, and 88.7 parts deionized water.

[0086] The copper acetate was purchased from Xiamen Haibiao Technology Co., Ltd.

[0087] PEG-400 was purchased from Guangzhou Nanjia Chemical Co., Ltd.

[0088] AEO-10 ​​was purchased from Shanghai Huijun Chemical Co., Ltd.

[0089] MOA-3PK was purchased from Shanghai Huijun Chemical Co., Ltd.

[0090] Isopropyl alcohol was purchased from Shanghai Kelon Chemical Co., Ltd.

[0091] CAB-35 was purchased from Shandong Yousuo Chemical Technology Co., Ltd.

[0092] Methylene blue (CAS: 7220-79-3) was purchased from Zhengzhou Honghai Dyestuff & Chemical Co., Ltd.

[0093] The deionized water was purchased from Shanghai Jingchun Water Treatment Technology Co., Ltd.

[0094] The second aspect of this example provides a method for preparing a copper-based urea crystal scavenger for automotive use, including:

[0095] S1. Dilute PEG-400 with deionized water, then stir at 30°C for 5 minutes;

[0096] S2. Add AEO-10 ​​and stir at 25°C for 5 minutes.

[0097] S3. Add isopropanol and stir at 25°C for 5 minutes.

[0098] S4. Add MOA-3PK and stir at 25°C for 5 minutes.

[0099] S5. Add copper acetate and stir at 25°C for 10 minutes.

[0100] S6. Add CAB-35 and stir at 20°C for 5 minutes.

[0101] S7. Add methylene blue and stir at 25°C for 10 minutes to obtain the automotive copper-based urea crystal remover.

[0102] Performance testing

[0103] I. Average Effective Mileage Test

[0104] After ruling out mechanical and electronic malfunctions in vehicles with urea crystallization problems, the automotive urea crystal remover from Examples 1 and 1-2 was thoroughly mixed with automotive urea solution AUS32 at a mass ratio of 1:600. This mixture was then added to the urea tank of the faulty vehicle and subjected to test transport, as detailed below. Figure 1 As shown, the effective mileage is reached when the fault light is cleared. Each group is tested 4 times, and the average value is taken as the average effective mileage. The test results are detailed in Table 1.

[0105] There are two test routes: one is a Guangzhou-Shanghai round trip, i.e., Guangzhou to Shanghai; the other is a Guangzhou-Chengdu round trip, i.e., Guangzhou to Chengdu. The Guangzhou-Shanghai route has a similar altitude, while the Guangzhou-Chengdu route involves traveling from low to high altitude areas.

[0106] The test vehicle was a Scania G420. All Scania G420 cars have the same engine, which avoids the experimental errors caused by different manufacturers and models of the engine.

[0107] Table 1

[0108]

[0109] As shown in Table 1, the urea crystal remover prepared in Example 1 had the shortest average effective mileage and excellent urea crystal dissolution effect. Furthermore, Table 1 also shows that in the same experimental group, the effective mileage on the Guangzhou-Shanghai route was shorter than that on the Guangzhou-Chengdu route. This is mainly because the altitude gradually increases along the Guangzhou-Chengdu route, the oxygen content in the air gradually decreases, the engine combustion performance declines to some extent, and more pollutants are generated. Therefore, the effective mileage on the Guangzhou-Chengdu route is longer than that on the Guangzhou-Shanghai route.

[0110] II. Schematic diagram of urea crystal ablation

[0111] Test Example 1: Before adding the automotive urea crystal remover, the vehicle worked for 6 days, 8 hours per day, accumulating 48 hours of operation. The exhaust pipe SCR catalytic converter of the vehicle with urea crystallization problems was then disassembled and observed. The test results are as follows: Figure 2-3 As shown.

[0112] from Figure 2-3 As can be seen from the example, using the automotive urea crystal remover of Example 1 can effectively reduce the amount of urea crystals in the SCR catalyst of the exhaust pipe of a vehicle with urea crystallization failure, and the crystals will fall off naturally.

[0113] The odometer reading after using urea, including the rare earth water-based environmentally friendly automotive urea crystal remover prepared in Example 1, is as follows: Figure 4 As shown in Figure 5, after using a barrel of urea containing the rare earth water-based environmentally friendly automotive urea crystal remover prepared in Example 1, the odometer reading is reset at 10,000 km. This shows that the product is usable and supports a urea usage mileage of up to 1,316 km, while urea without the urea crystal remover can only be used for 900-1,000 km.

[0114] III. Effective Mileage Exchange Experiment

[0115] The urea crystallizer prepared in Example 1 and the automotive urea solution AUS32 were thoroughly mixed, and the effective mileage was tested. The test method was the same as that in Test 1. The experimental results are detailed in Table 2.

[0116] Table 2

[0117]

[0118] The experimental results in Table 2 show that the urea crystal cleaner prepared in this invention has an effective range of up to 2091 km, and the product has excellent urea crystal dissolution effect.

[0119] The urea crystallizing cleaner prepared in Examples 1-2 was thoroughly mixed with automotive urea solution AUS32, and the effective mileage was tested. The test method was the same as that in Test 1. The experimental results are detailed in Table 3.

[0120] Table 3

[0121]

[0122] The experimental results in Table 3 show that using a combination of cerium citrate and lanthanum acetate as catalysts, the automotive urea crystal remover has a better urea crystal dissolution effect, resulting in a shorter effective mileage.

[0123] IV. Stability Test

[0124] The stability of the automotive urea crystal remover of Example 1 and the automotive copper-based urea crystal remover of Comparative Example 3 was tested at different temperatures. The experimental results are detailed in Table 4.

[0125] Table 4

[0126]

[0127] As can be seen from the experimental results in Table 4, the urea crystallizer provided in this application exhibits superior low-temperature stability. This is mainly because isopropanol has a lower ability to constrain colloids in the solution compared to ethylene glycol tert-butyl ether. Furthermore, the urea crystallizer provided in this application does not exhibit solid precipitation when compounded with inferior urea, demonstrating a certain degree of SCR carrier catalyst protection. In contrast, the urea crystallizer provided in Comparative Example 3 exhibits solid precipitation when compounded with inferior urea. Additionally, ethylene glycol tert-butyl ether is less toxic than isopropanol, making it more environmentally friendly in the production process.

Claims

1. A rare earth water-based environmentally friendly automotive urea crystal remover, characterized in that, The raw materials for preparation, by mass parts, include: 0.005-0.2 parts rare earth-based catalyst, 3-10 parts surfactant, 1-3 parts dispersant, 5-10 parts stabilizer, and 80-100 parts deionized water; The rare earth-based catalysts include at least cerium-based catalysts; The surfactants mentioned include fatty alcohol polyoxyethylene ethers; The stabilizer includes ethylene glycol tert-butyl ether; The dispersant includes one or more of polyethylene glycol, isopropanol, butanol, ethanol, propylene glycol, or butanediol.

2. The rare earth water-based environmentally friendly automotive urea crystal remover according to claim 1, characterized in that, The cerium-based catalyst includes one or more of cerium sulfate, cerium nitrate, cerium acetate, or cerium citrate.

3. The rare earth water-based environmentally friendly automotive urea crystal remover according to claim 2, characterized in that, The rare earth-based catalysts also include lanthanum-based catalysts.

4. The rare earth water-based environmentally friendly automotive urea crystal remover according to claim 3, characterized in that, The lanthanum-based catalyst includes one or more of lanthanum sulfate, lanthanum nitrate, lanthanum acetate, or lanthanum citrate.

5. The rare earth water-based environmentally friendly automotive urea crystal remover according to claim 4, characterized in that, When the rare earth-based catalyst includes cerium-based catalyst and lanthanum-based catalyst, the mass ratio of cerium-based catalyst to lanthanum-based catalyst is 1:(0.05-0.1).

6. The rare earth water-based environmentally friendly automotive urea crystal remover according to claim 1, characterized in that, The HLB value of the fatty alcohol polyoxyethylene ether is 12-14.

7. A method for preparing a rare earth water-based environmentally friendly automotive urea crystallizer according to any one of claims 1-6, characterized in that, Includes the following steps: By mixing rare earth-based catalysts, surfactants, dispersants, stabilizers, and deionized water, a rare earth water-based environmentally friendly automotive urea crystal remover is obtained.

Images