Plasma-Assisted Selective Catalytic Reduction for Low-Temperature Removal of NOx and Soot Simulant

Van Toan Nguyen,Duc Ba Nguyen,Young Sun Mok,Iljeong Heo

doi:10.3390/catal9100853

Abstract

The challenge that needs to be overcome regarding the removal of nitrogen oxides (NOx) and soot from exhaust gases is the low activity of the selective catalytic reduction of NOx at temperatures fluctuating from 150 to 350 °C. The primary goal of this work was to enhance the conversion of NOx and soot simulant by employing a Ag/α-Al2O3 catalyst coupled with dielectric barrier discharge plasma. The results demonstrated that the use of a plasma-catalyst process at low operating temperatures increased the removal of both NOx and naphthalene (soot simulant). Moreover, the soot simulant functioned as a reducing agent for NOx removal, but with low NOx conversion. The high efficiency of NOx removal required the addition of hydrocarbon fuel. In summary, the combined use of the catalyst and plasma (specific input energy, SIE ≥ 60 J/L) solved the poor removal of NOx and soot at low operating temperatures or during temperature fluctuations in the range of 150–350 °C. Specifically, highly efficient naphthalene removal was achieved with low-temperature adsorption on the catalyst followed by the complete decomposition by the plasma-catalyst at 350 °C and SIE of 90 J/L.

Highlights

There is considerable attention being paid to the removal of nitrogen oxides (NOx ) and soot produced by diesel engines [1,2,3,4,5,6], because these engines using petroleum products continue to be a crucial energy source [7]
The discharge power increased at high temperatures, which can be explained by an increase in the dielectric barrier discharge (DBD) charge
This research aimed to examine the removal of NOx and the soot simulant from diesel emissions in a fixed-bed DBD reactor in the temperature range from 150 to 350 ◦ C

Summary

Introduction

There is considerable attention being paid to the removal of nitrogen oxides (NOx ) and soot produced by diesel engines [1,2,3,4,5,6], because these engines using petroleum products continue to be a crucial energy source [7]. The emission of CO, hydrocarbons (HCs), NOx , and soot (particulate matter) from diesel engines is an environmental concern, because these gases are a major source of air pollution [8]. The instantaneous substitution of diesel engines with environmentally friendly systems, namely wind power plants, solar power plants, and electric cars would have considerable economic consequences. The removal of harmful gases, such as NOx and soot, from exhaust gases before it is released to the atmosphere would be an effective method in this regard

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