An investigation on the catalytic characteristic of NO reduction in SCR systems

Abstract The Selective catalytic reduction (SCR) technology is an effective and economical method for reducing NO x emissions from the heavy duty diesel engine. To ensure a reasonable design of the SCR system, it is critical to understand the effects of space velocity (GHSV), NO 2 /NO x ratio, NH 3 /NO x ratio and structural parameters of the SCR reactor on the NO x conversion efficiency. Using the experimental method to conduct all the investigations though the entire development cycle of SCR system is expensive and would cost a long time. Numerical method as a complementary tool to bench tests can help to optimize the design and shorten the development cycle of SCR system. In this paper, a mathematical model is developed to predict the NO x conversion efficiency over a Cu catalyst. The model is calculated in the MATLAB environment. The simulation results agree well with the experimental data, which indicates that the mathematical model is reliable and can effectively predict the performance of the SCR catalytic system. Then the effects of the parameters, such as space velocity, NO 2 /NO x ratio, NH 3 /NO x ratio, length, diameter and number of channels per square inch (CPSI) of the SCR reactor on the NO x conversion efficiency were studied.