Effect of selenium addition on the properties and NOX conversion performance of silver based HC-SCR catalyst

This study aimed to contribute to the limited literature in this field by investigating the effect of hydrocarbon-selective catalytic reduction system (HC-SCR) on the conversion rates of nitrogen oxides (NOX). For this purpose, Ag/TiO2, Ag-Ca/TiO2, Ag-Ca-Se (%0,5) /TiO2, Ag-Ca-Se (%1) /TiO2, Ag-Ca-Se (%1,5) / TiO2 catalyst were prepared by the impregnation method. Cordierite pretreated with oxalic acid was used as the catalyst main carrier body, while ethyl alcohol used as the reductant agent. The NOX conversion performance of the catalysts were analyzed in the SCR system. Experiments were carried out using a two-cylinder V type diesel engine operating at a constant speed of 3000 rpm, under 1 kW, 3kW, 5 kW loads, at a range of 180 °C to 270 °C, at 30000 h-1 constant gas hourly space velocity (GHSV). The chemical and structural properties of the catalysts were investigated with the help of Scannig Electron Microscope (SEM), X-RayDiffractometer (XRD) and Brunauer-Emmet-Teller analyzer. As a result, the highest NOx conversion was observed at 5 kW and 270 °C with Ag-Ca/TiO2 catalyst including %1 selenium while the lowest conversions belongs to Ag-Ca/TiO2 at 1 kW and 180 °C.