Urea solution for vehicles and preparation method thereof

Abstract

The invention discloses an automotive urea solution and a preparation method thereof, and relates to the technical field of chemical engineering, the automotive urea solution comprises the following components: urea, itaconic acid, surface modified nano silicon dioxide, tetrasodium iminodisuccinate, glyceryl ketal and deionized water. According to the efficient and stable urea solution for the vehicle, the problems that in the prior art, stability is poor, crystallization is prone to occurring and the like are solved through innovative combined components and the optimized proportion of the innovative combined components, and meanwhile the reduction efficiency of the urea solution in an SCR system is improved.

Description

Technical Field

[0001] The present invention relates to the field of chemical engineering technologies, and particularly relates to a vehicle urea solution and a preparation method thereof. Background Art

[0002] Since environmental protection departments in various countries have proposed to further reduce nitrogen oxide pollutants emitted by diesel engines. Engine manufacturers have started to use SCR technology (Selective Catalytic Reduction Technology) to meet the requirements of environmental protection departments. Diesel engine exhaust treatment fluid (commonly known as: automotive urea, vehicle urea, automotive environmental protection urea, diesel vehicle exhaust purification fluid in China) is a consumable that must be used in SCR technology. Vehicle urea is an aqueous urea solution with a concentration of 32.5% and ultrapure water as the solvent, and the production raw materials are special raw materials for vehicle urea and ultrapure water. However, existing vehicle urea solutions are prone to problems such as crystallization, decomposition, or decreased stability during long-term storage or in extreme environments, affecting their use effects. Therefore, it is of great significance to develop a vehicle urea solution with high efficiency, stability, and strong adaptability. Summary of the Invention

[0003] The purpose of the present invention is to provide a highly efficient and stable vehicle urea solution, which solves the problems of poor stability and easy crystallization in the prior art through an innovative combination of components and their optimized ratios, and simultaneously improves its reduction efficiency in the SCR system.

[0004] The present invention adopts the following technical scheme: A vehicle urea solution, whose components include urea, itaconic acid, surface-modified nano-silica, sodium iminodisuccinate, glycerol ketal, and deionized water.

[0005] Preferably, the components are calculated by weight as follows: 66 parts of water, 32.5 parts of urea, 0.1 - 0.15 parts of itaconic acid, 1 - 1.2 parts of glycerol ketal, 0.05 - 0.1 parts of silica, and 0.1 - 0.15 parts of sodium iminodisuccinate.

[0006] Preferably, the surface-modified nano-silica is hydrophobic silane-coupled modified nano-silica.

[0007] A preparation method of a vehicle urea solution, the production steps are as follows: Heat deionized water to 35°C; Add urea and stir until completely dissolved; Sequentially add itaconic acid, sodium iminodisuccinate, and glycerol ketal, and stir evenly to obtain solution A; Disperse the surface-modified nano-silica in deionized water, and obtain solution B after ultrasonic treatment; Mix solution A and solution B, and continue to stir for several minutes; Cool to room temperature and obtain the vehicle urea solution after filtration.

[0008] Advantages of the present invention: Strong anti-crystallization performance, strong stability, good anti-pollution performance, excellent dispersibility, environmental protection and safety, and strong low-temperature adaptability. Specific embodiments

[0009] The present invention will be further described below in conjunction with embodiments.

[0010] For the components, raw materials, etc. involved in the following embodiments, unless otherwise specified, they are all conventional components, raw materials, etc. existing in the prior art and can be obtained through regular commercial channels.

[0011] Embodiment 1: A vehicle urea solution: Take 66 kg of deionized water and heat it to 35 °C; Add 32.5 kg of urea and stir until completely dissolved; Sequentially add 0.15 kg of itaconic acid, 0.1 kg of tetrasodium iminodisuccinate, and 1.2 kg of glycerol ketal, and stir evenly; Disperse 0.05 kg of surface-modified nano-silica in 1 kg of deionized water, add it to the above solution after ultrasonic treatment, and continue to stir for 30 minutes; Cool to room temperature and obtain the vehicle urea solution after filtration.

[0012] Embodiment 2: A vehicle urea solution: Take 66 kg of deionized water and heat it to 35 °C; Add 32.5 kg of urea and stir until completely dissolved; Sequentially add 0.15 kg of itaconic acid, 0.1 kg of tetrasodium iminodisuccinate, 0.02 kg of p-toluenesulfonic acid, and 1.2 kg of glycerol ketal, and stir evenly; Disperse 0.05 kg of surface-modified nano-silica in 1 kg of deionized water, add it to the above solution after ultrasonic treatment, and continue to stir for 30 minutes; Cool to room temperature and obtain the vehicle urea solution after filtration.

[0013] Embodiment 3: A vehicle urea solution: Take 66 kg of deionized water and heat it to 35 °C; Add 32.5 kg of urea and stir until completely dissolved; Sequentially add 0.15 kg of itaconic acid, 0.1 kg of tetrasodium iminodisuccinate, 0.04 kg of p-toluenesulfonic acid, and 1.3 kg of glycerol ketal, and stir evenly; Disperse 0.05 kg of surface-modified nano-silica in 1 kg of deionized water, add the above solution after ultrasonic treatment, and continue stirring for 30 minutes; Cool to room temperature and filter to obtain the vehicle urea solution.

[0014] Example 4: A vehicle urea solution: Take 66 kg of deionized water and heat it to 35 °C; Add 32.5 kg of urea and stir until completely dissolved; Add 0.15 kg of itaconic acid, 0.1 kg of tetrasodium iminodisuccinate, 0.06 kg of sodium p-toluenesulfonate and 1.2 kg of glycerol ketal in sequence, and stir evenly; Disperse 0.05 kg of surface-modified nano-silica in 1 kg of deionized water, add the above solution after ultrasonic treatment, and continue stirring for 30 minutes; Cool to room temperature and filter to obtain the vehicle urea solution.

[0015] Example 5: A vehicle urea solution: Take 66 kg of deionized water and heat it to 35 °C; Add 32.5 kg of urea and stir until completely dissolved; Add 0.15 kg of itaconic acid, 0.1 kg of tetrasodium iminodisuccinate, 0.08 kg of sodium p-toluenesulfonate and 1.2 kg of glycerol ketal in sequence, and stir evenly; Disperse 0.05 kg of surface-modified nano-silica in 1 kg of deionized water, add the above solution after ultrasonic treatment, and continue stirring for 30 minutes; Cool to room temperature and filter to obtain the vehicle urea solution.

[0016] Example 6: A vehicle urea solution: Take 66 kg of deionized water and heat it to 35 °C; Add 32.5 kg of urea and stir until completely dissolved; Add 0.15 kg of itaconic acid, 0.1 kg of tetrasodium iminodisuccinate, 0.1 kg of sodium p-toluenesulfonate and 1.2 kg of glycerol ketal in sequence, and stir evenly; Disperse 0.05 kg of surface-modified nano-silica in 1 kg of deionized water, add the above solution after ultrasonic treatment, and continue stirring for 30 minutes; Cool to room temperature and filter to obtain the vehicle urea solution.

[0017] Note: The surface-modified nano-silica is hydrophobic, and the nano-silica modified by silane coupling produced by a certain company is used in all examples.

[0018] Test items and experimental methods (1) Low-temperature crystallinity test Experimental method: Divide the samples into transparent glass bottles, seal them, and place them in low-temperature chambers at -20°C, -30°C, and -40°C respectively; observe the crystallization state every 24 hours, and record the time of the first appearance of crystallization and the proportion of the crystallization amount.

[0019] Experimental results: Experimental temperature Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 -20℃ No crystallization No crystallization No crystallization No crystallization No crystallization No crystallization -30℃ No crystallization No crystallization No crystallization No crystallization No crystallization No crystallization -40℃ 15 days, partial crystallization 15 days, partial crystallization 16 days, partial crystallization 16 days, partial crystallization 17 days, partial crystallization 18 days, partial crystallization (2) Biuret formation rate test Experimental method: Accelerate the aging of the samples in a constant-temperature oven at 50°C for 30 days to simulate long-term storage; use high-performance liquid chromatography (HPLC) to detect the biuret content.

[0020] Experimental results: Biuret content Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Initial content ≤0.02% ≤0.02% ≤0.02% ≤0.02% ≤0.02% ≤0.02% Content after 30 days of aging ≤0.05% ≤0.04% ≤0.04% ≤0.04% ≤0.05% ≤0.06% Increase rate of generation rate +0.03% +0.02% +0.02% +0.02% +0.03% +0.04% (3) Metal corrosion rate test Experimental method: Immerse standard test pieces of aluminum, copper, and stainless steel in the samples and test them under the conditions of 50°C for 7 days; Calculate the mass loss per unit area (g / m²·h).

[0021] Experimental results: (g / m²·h) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Aluminum corrosion rate ≤0.0015 ≤0.0014 ≤0.0012 ≤0.0015 ≤0.0016 ≤0.0018 Copper corrosion rate ≤0.0025 ≤0.0022 ≤0.0018 ≤0.0025 ≤0.0025 ≤0.0030 Stainless steel corrosion rate ≤0.0005 ≤0.0004 ≤0.0003 ≤0.0005 ≤0.0005 ≤0.0005 (4) Stability test Experimental method: Centrifugation experiment (3000 rpm, 30 minutes) to observe stratification or precipitation.

[0022] Experimental results: Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Precipitation amount after centrifugation None None None None None None From the above experimental results, it can be seen that the data of each embodiment are significantly better than those of existing products on the market.

Claims

1. A vehicle urea solution, characterized in that, Its components include urea, itaconic acid, surface-modified nano-silica, tetrasodium iminodisuccinate, glycerol ketal, and deionized water.

2. The diesel exhaust fluid according to claim 1, characterized in that, The amounts of the respective components by weight are as follows: 66 parts of water, 32.5 parts of urea, 0.1 - 0.15 parts of itaconic acid, 1 - 1.2 parts of glycerol ketal, 0.05 - 0.1 parts of silica, and 0.1 - 0.15 parts of tetrasodium iminodisuccinate.

3. The diesel exhaust fluid according to claim 2, wherein The surface-modified nano-silica is hydrophobic silane coupling-modified nano-silica.

4. The preparation method of the diesel exhaust fluid according to claim 1, characterized in that The manufacturing steps are as follows: Heat the deionized water to 35 °C; Add urea and stir until completely dissolved; Add itaconic acid, tetrasodium iminodisuccinate, and glycerol ketal in sequence, and stir evenly to obtain Solution A; Disperse the surface-modified nano-silica in deionized water and obtain Solution B after ultrasonic treatment; Mix Solution A and Solution B and continue stirring for several minutes; Cool to room temperature, filter to obtain the vehicle urea solution.