Automotive urea is essential for heavy-duty diesel vehicles to meet the National IV emission standards. Automotive urea refers to a urea-water solution with a urea concentration of 32.5% and a solvent of ultrapure water. Raw materials are dedicated raw materials for automotive urea and ultrapure water.
Domestic Automotive Urea is Mainly Purified from Industrial Urea, the Main Principles of which are:
- Urea undergoes hydrolysis in an aqueous solution at a temperature of 70-75°C.
- Urea crystallizes out of the aqueous solution at temperatures below 30°C.
- Each time hydrolysis and crystallization occur, the purity is significantly improved. Generally, one-time hydrolysis and crystallization of industrial-grade urea can meet the requirements of automotive urea standards, with a production ratio of 1.5:1.
Automotive urea must use first-grade ultrapure water in the electronics industry. The carrier of the SCR catalyst is highly susceptible to metal ion poisoning, which can cause the catalyst to lose its catalytic effect. Therefore, the automotive urea solution must use first-grade ultrapure water (resistance ≥ 18MΩ/cm). The automotive urea solution will begin to freeze at -11°C and will completely freeze at -20°C in actual use. Currently, technology is used to prevent solution freezing by adding modifiers to lower the solution freezing point and using heating devices.
The diesel engine exhaust treatment fluid (commonly known as automotive urea, automotive environmental urea), called AdBlue in China and Europe, DEF in the Americas, and ARLA32 in Brazil, is a high-purity transparent liquid composed of 32.5% high-purity urea and 67.5% deionized water, with a faint ammonia smell. If it spills out, the water evaporates and forms crystals.
AdBlue is used for passenger cars, trucks, buses, and heavy-duty non-road diesel engine vehicles equipped with SCR (Selective Catalytic Reduction) systems. It is a consumable product that must be used in the SCR technology to convert harmful nitrogen oxides emitted by diesel engines into harmless water vapor and nitrogen. The main components of the SCR system include the catalyst, AdBlue injection device, AdBlue container, and AdBlue dosing controller.
In conjunction with SCR technology, AdBlue 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, approximately 1.5 liters per 100 kilometers of highway driving.
AdBlue can only be used in engine combinations equipped with SCR systems because it is neither fuel nor a fuel additive. It complies with ISO22241, DIN70070, and CEFIC standards to ensure the effective operation of SCR systems and is not harmful to the environment, and is classified as a low-risk transportable material.