Impact of Catalyst Geometry on Diffusion and Selective Catalytic Reduction Kinetics under Elevated Pressures

Area of Science:

• Marine engineering
• Environmental catalysis
• Chemical kinetics

Background:

• Marine diesel engines face challenges with high sulfur fuels and low exhaust gas temperatures.
• Selective Catalytic Reduction (SCR) upstream of the turbocharger is a potential solution for nitrogen oxide (NOx) reduction.
• Optimizing SCR performance requires understanding catalyst behavior under specific marine engine conditions.

Purpose of the Study:

• To investigate the impact of catalyst geometry on Selective Catalytic Reduction (SCR) kinetics in marine diesel engine applications.
• To understand how catalyst design influences NOx reduction efficiency, ammonia slip, and gas diffusion rates.
• To elucidate the extent, trends, and sources of these effects under elevated pressures.

Main Methods:

• Systematic testing of SCR catalysts with controlled variations in geometry.
• Evaluation of catalysts with equal geometry but differing intrinsic activity.
• Analysis of SCR kinetics under simulated marine diesel engine exhaust conditions, including high pressure.

Main Results:

• Catalyst geometry demonstrably affects SCR kinetics, NOx reduction, and ammonia slip.
• Specific geometric configurations show trends influencing gas diffusion rates under elevated pressures.
• The interplay between geometry and intrinsic activity is crucial for optimizing SCR performance.

Conclusions:

• Catalyst geometry is a critical design parameter for SCR systems in marine diesel engines, especially with high sulfur fuels.
• Understanding these geometric impacts is essential for achieving target NOx reductions while minimizing ammonia slip.
• Further research into catalyst geometry can lead to more efficient and compliant marine emission control technologies.