EFEK DYNAMIC TWISTED MIXER TERHADAP DISTRIBUSI AMONIA PADA SISTEM NH3 – SCR CATALYTIC FILTER MENGGUNAKAN FILTER DIA – SCHUMALITH UNTUK APLIKASI MESIN DIESEL AUTOMOTIVE DENGAN SIMULASI NUMERIK

Abstract

Nowadays global warming is increasingly interfere with human life, one of the causes of global warming is air pollution caused by exhaust gas from the vehicle. An effort to reduce air pollution caused by diesel engine needed a tool to convert pollutants into green elements. The tool is Selective Catalytic Reduction (SCR), which is a tool that can converts nitrogen oxides (NOx) with catalyst equipment to become diatomic nitrogen (N2) and water vapor (H2O). The reagents which is used in SCR systems is ammonia (NH3 From the simulation, the result is a contour of ammonia mass fraction, and then calculating the value of mixing index in the SCR system. With the twisted mixer equipment, higher mixing index can be achieved in a relatively short distance. At GHSV 10000 mixing index reached 0.900 in the SCR system with twisted mixer and 0.822 in the SCR system without twisted mixer. The increase of the mixing index in the region where twisted mixer has applied can be reached 137.2% of the SCR system without twisted mixer. ), this reagent is added to the exhaust gas stream. To speed up the process of mixing the reagent as a species injection with the exhaust gas then applied a twisted mixer device in the exhaust gas flow. Simulation of species mixing is to determine the mixing index and flow characteristics that occur due to the twisted mixer device in the SCR system. By applying a straight delta wings mixer the improvement of flow mixing can be achieved. The turbulent flow generated by straight delta wings is proved to be very useful for significant mixing enhancement within a short distance. Beside turbulent flow, swirling flow is another major contributor for higher flow mixing index and useful for mixing enhancement through longer distance. Porous medium used in this project is Dia-Schumalith filter. The element filters of Dia-Schumalith has been tested as a filter particles from the exhaust gas with high temperature. Keywords: CFD Modeling, Selective Catalytic Reduction, Dia-Schumalith filter, aftertreatment system.