Bench-scale NO removal using in-situ fuel-based reductant under rotating arc plasma conditions

Abstract

Nitrogen oxide (NOx) emissions pose major human health and environmental concerns. Gliding arc plasma is a promising technology for reforming various chemicals. To the best of our knowledge, the application of rotating arc plasma for the reforming of diesel fuel as a reductant coupled to selective catalytic reduction (SCR) on the scale of real-world conditions has not been reported yet. This study aimed to investigate the reduction of NOx using hydrocarbons, as reducing agents, supplied through a rotating arc plasma reformer for SCR. Dodecane (C12H26) was selected as hydrocarbon fuel to represent diesel. The effects of the carbon-to-oxygen ratio and its associated products with ozone addition over different catalyst temperatures from room temperature (22 ± 4 °C) to 300 °C were investigated. After investigating fuel-based reductants, NO was supplied to the bench-scale system as a NOx source. Moreover, NOx removal using plasma-derived hydrocarbon species was investigated using in-situ fourier transform infrared spectroscopy. We found that an optimal carbon-to-oxygen ratio (1.4) was critical for NOx removal. Additionally, up to 95% De-NOx could be achieved as the catalyst temperature increased. Besides, additional ozone injection increased the De-NOx performance at a catalyst temperature <250 °C because of the enhanced oxygenated hydrocarbon species.