IMPROVEMENT OF NOX REDUCTION RATE OF UREA SCR SYSTEM
APPLIED FOR AN NON-ROAD DIESEL ENGINE |
Joonsoo Han1, Taemin Kim2, Haksup Jung3, Sukang Pyo3, Gyubaek Cho1, Youngtaig Oh4, Hongsuk Kim1 |
1Korea Institute of Machinery & Materials 2E&D Corporate Ltd 3Kukje Machinery Company 4Chonbuk National University |
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ABSTRACT |
Urea SCR technology has been widely used to reduce NOx emissions of diesel engines. Despite remarkable
development for decades, more advanced control and optimization of urea SCR systems are still required as global NOx
emissions standards are expected to become more stringent. This study investigated several influential parameters of urea SCR
system to improve NOx reduction efficiency. This study uses a commercialized UWS (Urea Water Solution) supply system
and a SCR catalyst which was installed in the exhaust line of a non-road CRDI (Common Rail Direct Injection) diesel engine.
From this study, it was found that the low space velocity of SCR catalyst is essential for high NOx reduction efficiency,
especially at low temperatures. Early injection of UWS enhances the overall NOx reduction efficiency if UWS injection was
carefully controlled to avoid urea deposits. Rich injection of UWS with AOC is a good strategy for high NOx reduction
efficiency. However, NOx reproduction in the AOC, which has an adverse effect on the overall NOx reduction rate, occurs at
high exhaust gas temperatures. System insulation also can improve the NOx reduction efficiency by a few percentage points. |
Key Words:
Urea SCR (Selective Catalytic Reduction), NOx (Nitrogen Oxides), UWS (Urea Water Solution), Non-road
diesel engine, AOC (Ammonia Oxidation Catalyst) |
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