Adblue is a necessary product for heavy-duty diesel vehicles to meet the China IV emission standard. Adblue refers to urea aqueous solution with a urea concentration of 32.5% and a solvent of ultrapure water, and the raw materials are urea crystals and ultrapure water. In order for diesel vehicles such as heavy-duty trucks and buses to meet the National IV emission standards, a suitable SCR system must be selected in exhaust gas treatment, and this system must use urea solution to treat nitrogen oxides in the exhaust gas. Therefore, Adblue solution has become a necessary product for heavy-duty trucks and buses to meet the China IV emission standard.
SCR is the best choice for emission reduction in China. At present, the current domestic diesel national standard GB19147-2009 requires a sulfur content of ≤ 350ppm, while ECR-DOC technology requires that the sulfur content of oil is below 10ppm, so it does not have the conditions for promotion in China for the time being. SCR, on the other hand, can withstand 350ppm of sulfur-containing oils, so it has a technical basis for promotion. Because the China IV engine using SCR technology has better fuel economy than EGR technology, small engine changes, lower fuel and oil requirements, advantages in the continuity of technology upgrades, good durability of SCR catalytic converters and no risk of catalytic converter blockage, SCR technology is the most suitable for China's national conditions of heavy-duty diesel vehicle emission reduction technology route.
Adblue is an aqueous urea solution with a concentration of 32.5% and the solvent is ultrapure water, and the raw materials for production are urea crystals and ultrapure water, and the key point is the purity of the raw materials. From the perspective of production process, although Adblue has higher requirements for raw material purity than general industrial demand, the current domestic process can meet the actual application needs. The production process of Adblue is not sufficient to create high barriers to entry.
Domestic Adblue is mainly purified from industrial urea, and its main principle is:
At a temperature of 70-75 °C, urea is hydrolyzed in an aqueous solution.
At temperatures below 30 °C, urea is recrystallized from the aqueous solution.
Every time hydrolyzed crystallization, its purity will be greatly improved, generally using industrial first-class urea hydrolysis crystallization once, can meet the requirements of Adblue standards, and its output ratio is 1.5:1.
Adblue must use first-class ultrapure water from the electronics industry. Because the SCR catalyst carrier of Adblue is very prone to metal ion poisoning and thus loses the catalytic effect, the Adblue solution must use first-class ultrapure water (resistivity≥ 18MΩ?cm) in the electronics industry. The urea solution will begin to freeze at -11 °C, and in actual use, it will completely freeze at -20 °C. At present, the technology is to reduce the freezing point of the solution by adding modifiers, adding heating devices and other means to prevent the solution from solidifying.
Adblue is a solution prepared with pure water of high-purity urea without any other additives, and the urea content of 32.5% (mass fraction) in the solution is 32.5%. Most domestic and foreign heavy-duty diesel engine manufacturers have adopted SCR (selective catalytic reduction) technology to meet the requirements of Euro IV and Euro V motor vehicle emission standards. Vehicles that choose SCR technology must add urea solution as a catalytic reducing agent to meet vehicle emission standards.
Diesel engine exhaust treatment fluid (commonly known as: automotive urea, automotive urea, automotive environmental protection urea), known as Adblue in China and Europe, DEF in the Americas, and ARLA32 in Brazil. Adblue is a high-purity transparent liquid composed of 32.5% high-purity urea and 67.5% deionized water, with a faint smell of ammonia. If splashed, the water evaporates and crystallizes form. Adblue is a must-use consumable in SCR technology for cars, trucks, buses and heavy-duty off-highway diesel engine vehicles equipped with SCR (Automotive Selective Catalytic Reduction Exhaust Aftertreatment) systems, working with SCR catalysts to convert harmful nitrogen oxides emitted by diesel engines into harmless water vapor and nitrogen. The main components of the SCR system include a catalyst, an Adblue injection device, an Adblue container, and an Adblue dose controller. Almost all heavy-duty car manufacturers in Europe, the United States and Asia, including China, also equip vehicles with selective catalytic reduction systems with Adblue operating fluids to meet new NOx emission standards (such as Euro IV and Euro V) Adblue and SCR technologies can optimize engine performance and fuel consumption, reduce diesel consumption by up to 6%, and significantly reduce costs. The average consumption of Adblue is 5% of the general diesel consumption, which is about 1.5 liters per 100 km of highway driving. Adblue can only be used in engine combinations configured with SCR systems, as it is neither a fuel nor a fuel additive. Adblue implements compliance with standards within ISO22241, DIN70070 and CEFIC regulations to ensure the efficient operation of SCR systems. Adblue is not hazardous to the environment and is classified as a transportable liquid with the lowest risk.
At present, the domestic production of Adblue is dominated by small and medium-sized private enterprises, and the channel sales capacity is lacking. Domestic Adblue is mainly produced by Jiangsu Kelan Plant, Liaoning Rundi, Jingmai Chemical, Beijing Yili and other enterprises. Each company's annual production capacity is between 100,000 and 300,000 tons. Among them, Jiangsu Kelan and Liaoning Rundi have an annual output of 300,000 tons, and there are a series of modifier patents for low-temperature coagulation of automotive urea. Kuroxol has exported its urea solution to Russia, Eastern Europe and South America. However, for small private enterprises at present, the inability to master the core sales channels is the fundamental weakness of their development.
It is suitable for cars, trucks, buses, buses with diesel engines that meet the China IV emission standards
Adblue solution is a colorless, transparent and clear liquid with a concentration of 31.8%-33.2% for the reduction of nitrogen oxides. The currently used urea solution is generally composed of 32.5% high-purity urea and 67.5% deionized water. It has the effect of reducing pollution on the exhaust emissions of the car, and it can also maintain the car. Then we should pay attention to some problems when using automotive urea.
1. How to use urea for vehicles
Filling method: bagged, deflector filling;
Consumption standard: Taking the 32-liter urea tank device equipped with a heavy-duty truck vehicle as an example, the vehicle consumes about 100 liters of urea every 7200 kilometers, that is, it needs to be refilled every 2300 kilometers;
Recommended filling method: In order to avoid the lack of urea during driving, it is recommended to prepare 1-2 barrels of special urea solution packed in 10 liters with the car;
2. Purchase channels for automotive urea
It is understood that the current purchase channels for Adblue are: First, Adblue manufacturers have built their own distribution networks, and users can purchase them through urea manufacturers in various dealers; Second, heavy truck enterprises select spare parts dealers (regional agent libraries) for placement in various places, and users can contact dealers for purchase. You can also purchase in bulk through us
3. Precautions during the use of vehicle urea
◆When cleaning urea-related accessories, it must be rinsed with pure water, and tap water must not be used;
◆Contact urea shall not use: carbon steel, galvanized carbon steel, cast iron materials;
◆Metals or alloys that urea cannot touch: copper, bronze, lead, zinc, aluminum, aluminum alloy, magnesium, magnesium alloy, welding chat (containing lead), tin;
◆ During transportation and storage, light and high temperature should be avoided, transportation temperature and storage temperature in -5 °C ~ 25 °C, lower than -5 °C, heat preservation measures should be taken, higher than 25 °C to cool;
◆Reserve period:
1) Storage temperature≤ 10°C, storage period 36 months;
2) Storage temperature≤ 25°C, storage period 18 months;
3) Storage temperature≤ 30°C, storage period 12 months;
◆Unqualified or seriously contaminated urea must be recycled to the manufacturer and processed centrally. No direct discharge;
◆Once there is a fire, a large amount of water cooling must be used to avoid causing the pressure of the urea tank to rise sharply, and high temperature will cause urea decomposition and explosion;
◆If accidentally in the eyes, wash with plenty of water for at least 15 minutes, keep the eyes open when rinsing;
◆If inhaled accidentally, if there is respiratory tingling or discomfort, please transfer personnel to fresh air, if the symptoms persist, it is recommended to seek medical attention and explain that the ingested product is 32.5% urea solution;
◆If you come into contact with clothing or skin, wash your skin with mild soap and plenty of water, and seek medical attention if symptoms persist.
Basic information
Chemical formula: CO(NH2)2
英文别名：Carbamide；Urea solution； Urea， USP Grade Carbamide， USP Grade； Urea， MB Grade (1.12007)； Urea (Medical)； Urea-12C； 10-Hydroxy-2-trans-Decenoic Acid
CAS number: 57-13-6
EINECS number: 200-315-5
Molecular formula: CH4N2O
Molecular weight: 60.06
Exact mass: 60.03240
PSA：69.11000
LogP：0.42440
Physical and chemical properties
Properties: colorless or white needle-like or rod-like crystal, industrial or agricultural products are white with reddish solid particles, odorless and tasteless. The nitrogen content is about 46.67%.
Boiling point: 196.6 °Cat760mmHg.
Refractive index: n20/D 1.40.
Flash point: 72.7 °c.
Density: 1.335.
Melting point: 132.7 °c.
Water solubility: 1080 g/L (20°C).
Solubility: soluble in water, methanol, formaldehyde, ethanol, liquid ammonia and alcohol [1], slightly soluble in ether, chloroform, benzene. Weakly alkaline.
Chemical properties
It can react with acids to form salts. Has hydrolytic effect. At high temperatures, condensation reactions can be carried out to generate biuret, triuret and cyanuric acid. Heat to 160 °C to decompose, produce ammonia gas and change to isocyanic acid. Because it contains this substance in human urine, so the name urea. Urea contains 46% nitrogen (N), which is the highest nitrogen content in solid nitrogen fertilizer.
Urea can be hydrolyzed to generate ammonia and carbon dioxide under the action of acids, alkalis and enzymes (acids and alkalis need to be heated).
It is unstable to heat, and it will be deamined into biuret when heated to 150~160 °C. The copper sulfate and biuret reactions are purple and can be used to identify urea. If rapidly heated, it will be deamimonized and trimerized into a six-membered ring compound cyaneclic acid. (Mechanism: first deammonia to generate isocyanic acid (HN=C=O), and then trimer. ）
Reaction with acetyl chloride or acetic anhydride can produce acetylurea and diacetylurea.
Under the action of sodium ethoxide, it reacts with diethyl malonate to form malonylurea (also known as barbituric acid, because it has a certain acidity).
Under the action of basic catalysts such as ammonia, it can react with formaldehyde and condense into urea-formaldehyde resin.
It reacts with hydrazine hydrate to form aminourea.
Urea is easily soluble in water, 100 ml of water can be dissolved in 105 grams at 20 °C, and the aqueous solution is neutral. There are two types of urea products. Crystalline urea is white needle-like or prismatic crystal, strong hygroscopicity, agglomeration after moisture absorption, and the moisture absorption speed is 12 times faster than granular urea. Granular urea is a translucent particle with a particle size of 1~2 mm, with a smooth appearance and obvious improvement in hygroscopicity. At 20 °C, the critical hygroscopic point is 80% relative humidity, but at 30 °C, the critical hygroscopic point drops to 72.5%, so urea should be avoided in midsummer humid climate. When hydrophobic substances such as paraffin wax are added to urea production, its hygroscopicity is greatly reduced.
Preparation method
Method one
Ammonium carbamate is synthesized with carbon dioxide and ammonia at high temperature and high pressure, and after decomposition, absorption and transformation, crystallization, separation and drying.
Method two
The preparation method is to mix the purified ammonia with carbon dioxide massage ratio 2.8~4.5 into the synthesis tower, the pressure in the tower is 13.8~24.6 MPa, the temperature is 180~200 °C, the residence time of the reaction material is 25~40min, the urea solution containing excess ammonia and ammonium carbamate is obtained, and the urea solution after the separation of ammonia and ammonium carbamate is evaporated to more than 99.5% by reduced pressure and cooling, and then granulated in the granulation tower to obtain urea finished products.
Method three
The end product of protein metabolism in mammals in urea. In 1922, the industrial production of urea from ammonia and carbon dioxide was realized in Germany. Ammonia reacts with carbon dioxide to form carbamate amine, which is then dehydrated to produce urea.
Industrial production method
Production method: industrial use of liquid ammonia and carbon dioxide as raw materials, direct synthesis of urea under high temperature and high pressure conditions, the chemical reaction is as follows:
2NH3+CO2→NH2COONH4→CO(NH2)2+H2O。
Storage attention
1. If urea is stored improperly, it is easy to absorb moisture and agglomerate, affect the original quality of urea, and bring certain economic losses to farmers, which requires the majority of farmers to store urea correctly. Before use, be sure to keep the urea packaging bag intact, handle it gently during transportation, prevent rain, and store it in a dry, well-ventilated place with a temperature below 20 degrees.
2. If it is stored in large quantities, the bottom should be padded with a wooden square of about 20 cm, and there should be a gap of more than 50 cm between the upper part and the roof to facilitate ventilation and moisture, and an aisle should be left between the stacks and stacks. To facilitate inspection and ventilation. If the urea that has been opened is not used up, the mouth of the bag must be sealed in time for use next year.
3. Avoid contact with skin and eyes.
Application areas
Medical field
Dermatology uses certain agents containing urea to increase the moisture of the skin. Non-surgical nails are used in occlusive dressings that contain 40% urea.
To test for the presence of Helicobacter pylori, a carbon-14-breath test uses urea containing a carbon 14 or carbon 13 label. Because the urease of Helicobacter pylori uses urea to make ammonia to raise the pH of its surrounding stomach. The same principle can be used to test similar bacteria living in the stomachs of animals.
Agricultural sector
Urea is a high-concentration nitrogen fertilizer, which is a neutral fast-acting fertilizer and can also be used to produce a variety of compound fertilizers. No harmful substances remain in the soil, and long-term application has no adverse effects. Animal husbandry can be used as feed for ruminants. However, too high temperature in granulation will produce a small amount of biuret, also known as diurea, which has an inhibitory effect on crops. China stipulates that the content of urea biuret for fertilizer should be less than 0.5%. When the biuret content exceeds 1%, it cannot be used as seed fertilizer, seedling fertilizer and foliar fertilizer, and the urea content in other application periods should not be too much or too concentrated.
Pathways by which urea is produced in plants
Urea is an organic nitrogen fertilizer, which can be absorbed and utilized by crops after being hydrolyzed into ammonium carbonate or ammonium bicarbonate after urease in the soil. Therefore, urea should be applied 4~8 days before the fertilizer period of the crop.
Urea is suitable for base fertilizer and top dressing, and sometimes as seed fertilizer. Urea is in a molecular state before conversion, cannot be adsorbed by soil, and should be prevented from being lost with water; The ammonia formed after conversion is also volatile, so urea should also be deeply covered with soil. (A small part of the soil transformation applied to the soil is dissolved in the soil solution in a molecular state, adsorbed by the soil by hydrogen bonding, and most of the rest is hydrolyzed into ammonium carbonate under the action of urease, and then carbonic acid and ammonium hydroxide are generated.) Then ammonium ions can be absorbed by plants and adsorbed by soil colloids, and bicarbonate ions can also be absorbed by plants, so urea does not leave any harmful components after being applied to the soil. In addition, the biuret contained in urea can also be decomposed into ammonia and carbonic acid under the action of urease, and the conversion of urea in the soil is affected by the soil PH value, temperature and moisture, and the soil is neutral reaction, the higher the soil temperature when the water is appropriate, the faster the conversion; When the soil temperature is 10 °C, it takes 7-10 days for urea to be completely converted to ammonium nitrogen, 4-5 days when 20 °C, and 2-3 days when 30 °C. After urea hydrolysis to generate ammonium nitrogen, surface application will cause ammonia volatilization, especially alkaline or alkaline soil is more serious, so the application of urea should be deeply applied to the soil, paddy fields should be deeply applied to the reducing layer. ）
Urea is suitable for all crops and all soils, can be used as base fertilizer and top dressing, and can be applied in dry paddy fields. Because urea can accumulate a large number of ammonium ions in the soil, it will lead to a rise in PH by 2-3 units, coupled with urea itself contains a certain amount of biuret, its concentration at 500ppm, it will inhibit the young roots and shoots of crops, so urea should not be used as seed fertilizer.
Urea (nitrogen fertilizer) can promote cell division and growth, so that branches and leaves grow luxuriantly.
It can be used in large quantities as melamine, urea-formaldehyde ester, hydrazine hydrate, tetracycline, phenobarbital, caffeine, reduced brown BR, phthalocyanine B, phthalocyanine Bx, monosodium glutamate and other products production raw materials.
Adjust the amount of flowers
In order to overcome the size of the apple field, in the small year, 5-6 weeks after flowering (the critical period of apple flower bud differentiation, the growth of new shoots is slow or stopped, and the nitrogen content of leaves shows a downward trend) foliar spray 0.5% urea aqueous solution, spraying twice in a row, can increase the nitrogen content of leaves, accelerate the growth of new shoots, inhibit flower bud differentiation, and make the flower amount suitable for large years.
Thinning flowers and fruits
The flower apparatus of peach tree is more sensitive to urea but the response to the surface is more slow, therefore, foreign urea for peach and nectarine fruit thinning test, the results show that peach and nectarine flower thinning, need a large concentration (7.4%) to show good results, the most suitable concentration is 8%-12%, within 1-2 weeks after spraying, that is, the purpose of flower thinning and fruit thinning. However, the responses of different varieties at different times and under different land conditions need further experiments.
Rice seeding
In the hybrid rice seed production technology, in order to increase the outcrossing rate of the parent to increase the amount of hybrid rice seed production or sterile line breeding, erythoxin spraying the mother is generally used to reduce the degree of neck wrapping or completely withdraw it. Or spray the parent to regulate the growth of the two and synchronize the flowering period. Due to the high price of gibberellin, the cost of using it for seed preparation is high. People used urea instead of gibberellin for experiments, and 1.5%-2% urea was used in the peak stage of pregnancy and the first spike stage (20% of the panicles), and the breeding effect was similar to that of gibberellin, and did not increase the plant height.
Control pests
With urea, washing powder, water 4:1:400 parts, stirring and mixing, it can prevent aphids, red spiders, cabbage insects and other pests on fruit trees, vegetables, cotton, and the insecticidal effect is more than 90%.
Urea iron fertilizer
Urea forms chelated iron with Fe2+ in the form of complexes. This kind of organic iron fertilizer has low cost and has a good effect on preventing iron deficiency and green loss. In addition, 0.3% urea is added when foliar spraying 0.3% ferrous sulfate, and the effect of preventing green loss is better than that of single spray 0.3% ferrous sulfate.
Because urea has excellent dissolving dye properties, mild reduction/oxidation resistance and excellent hygroscopicity (see attached table), it is an excellent dye solvent/hygroscopic agent/viscose fiber extruder, resin finishing agent, and has a wide range of uses in the textile industry.
Comparison of urea with other hygroscopic agents in the textile industry: compared to its own weight.
Industrial applications
It has a brightening effect on chemical polishing of steel and stainless steel, and is used as a corrosion inhibitor in metal pickling, and is also used in the preparation of palladium activation liquid.
In industry, it is also used as a raw material for the manufacture of urea-formaldehyde resin, polyurethane, melamine-formaldehyde resin, and when urea is heated to 200 °C, solid trichloric acid (i.e. cyanuric acid) is generated. Derivatives of cyanuric acid trichloroisocyanuric acid, sodium dichloroisocyanate, tris(2-hydroxyethyl isocyanurate), tris(allyl) isocyanurate, tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanate, triglycidyl ether isocyanurate, melamine cyanurate complex, etc. have many important applications. The first two are new high-grade disinfection and bleaching agents, and the total production capacity of trichloroisocyanuric acid in the world exceeds 80,000 tons.
Selective reducing agent for combustion exhaust gas denitrification, and automotive urea, which is composed of 32.5% high-purity urea and 67.5% deionized water.
Selective catalytic reduction (SCR) exhaust aftertreatment is a technology that selectively reduces ammonia produced by the pyrolysis reaction of urea in combustion exhaust to carry out selective catalytic reduction reaction with nitrogen oxides (NOx) in automobile exhaust, and is a key and mainstream technology to reduce NOx, harmful substances in combustion exhaust gases such as combustion boilers and diesel engines. The SCR system is a necessary system to meet the strict emission regulations of modern vehicles, such as Euro IV./EURO V/VI (National IV/National V/National VI) regulations. Adblue is called Adblue in Europe and DEF (diesel exhaust treatment fluid) in the United States
