AUS 32 is an environmental emission-control solution specifically designed for diesel-powered railway locomotives, including diesel and diesel-electric trains.
Like automotive SCR systems, it is used to reduce nitrogen oxide (NOx) emissions generated by diesel engines.
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Why Do Trains Need Urea Solution?
Urea solution is not used as fuel.
Its purpose is to reduce harmful exhaust emissions.
- Reduce Nitrogen Oxides (NOx)： High-temperature combustion in diesel engines produces large amounts of NOx, one of the primary causes of acid rain and photochemical smog.
- Comply with Environmental Regulations： Modern diesel locomotives are equipped with Selective Catalytic Reduction (SCR) systems to convert harmful emissions into environmentally harmless substances.
How the SCR System Works:
The SCR system injects AUS 32 into the exhaust stream.
- Thermal Decomposition：High exhaust temperatures convert urea into ammonia (NH₃).
- Catalytic Reaction：Inside the catalyst, ammonia reacts with nitrogen oxides (NOx).
- Final Products：The reaction converts NOx into harmless:Nitrogen (N₂)Water Vapor (H₂O)
⚠️ Usage and Ingredient Precautions
- Composition Ratio: This solution typically consists of 32.5% high-purity urea and 67.5% deionized water.
- Do Not Mix: This is an industrial-grade high-purity solution. Do not use agricultural fertilizer-grade urea to prepare it yourself, as impurities will cause SCR catalyst blockage and damage.
- Consumption: Urea consumption is generally proportional to fuel consumption (approximately 3% to 6% of diesel consumption).
- What Happens If Not Added? If urea runs out and is not replenished, modern train computer systems may limit engine power or force shutdown to avoid exceeding emission standards and violating regulations.
