Selective Catalytic Reduction of NO_x of Ship Diesel Engine Exhaust Gas with C₃H₆ over Cu/Y Zeolite

Abstract

Various solid Cu-containing catalysts were prepared. Their performance in the selective catalytic reduction of NO x using propene as reducing agent from 150 to 450 °C in an O 2 -rich model exhaust gas in the presence of water vapor was investigated. This research aimed at the development of a catalytic NO x to N 2 (DeNO x ) step to be part of a ship diesel exhaust abatement system in combination with other techniques, such as nonthermal plasma. Among the catalysts tested, Cu on zeolite Y with an optimized load of 16 wt % (denoted as 16Cu/Y) displayed excellent DeNO x activity with highest selectivity toward N 2 at 290 °C. The influence of other variables, such as Cu load, calcination temperature, feed composition, and GHSV on the performance of 16Cu/Y was studied, as well. The highest N 2 yield of 98% was achieved using 2000 ppm of propene in the gas feed. The presence of O 2 proved to be a crucial factor for promoting the selective reduction of NO x with C 3 H 6 over this catalyst. On the other hand, the presence of water in the feed decreased NO x to N 2 conversion. However, the catalyst showed excellent stability over 120 h, even at high water concentration, and also after repeated heating from ambient temperature to 450 °C, and it was reusable after downtimes without remarkable loss in activity. The nature of the Cu species was studied by XPS, XRD, and TPR experiments.

High Zr-loaded SBA-15 cobalt catalyst for efficient NOx reduction in lean-burn exhaust

“…These results confirm the high tolerance of Co2/ZrSBADP2 under severe condition, such as car exhaust [14]. Figure 8c shows the performance of the catalyst in the presence of 7 vol% water vapor, as a typical value for a lean-burn engine exhaust [36]. The activity of the catalyst was remarkably enhanced by the presence of water vapor in the range of 300-350 , where the N2 yield increased from 18 % to 34 % and from 54 % to 70 % at 300 and 350 , respectively.…”

“…This trend demonstrates that the structural modification was more pronounced in the presence of a higher content of the cobalt species. Despite this reduction, the surface area of the catalysts was still higher than those of the zeolites and noble metal-based catalysts [15,35,36]. The large surface area of the prepared catalysts, resulting in more active sites for the chemisorption of the reactants and thus higher reaction rate, can be considered as one of the main advantages of the DP synthesis technique [37].…”

“…At high temperatures, higher concentration of reducing agent increases the formation of oxygenated hydrocarbon intermediate species (CxHyOz) which results in a strong enhancement in the catalytic activity towards N2 formation [36,68,69]. Moreover, at higher reducing agent concentration, the metal sites on the catalyst are reduced more efficiently which results in higher NOx reduction [36].…”

Silicotungstic acid modified Ce‐Fe‐Ox catalyst for selective catalytic reduction of NOx with NH3: Effect of the amount of HSiW

“…Nitrogen oxides (NO x ) from coal‐fired power plants have been broadly confirmed to be an unnegligible air pollutant. For the decline of NO x , an effective technology (selective catalytic reduction of NO with NH 3 ) is widely used to solve these problems . V 2 O 5 ‐WO 3 (MoO 3 )/TiO 2 catalysts have been applied widely in the industrial field as the representative of commercialized catalysts, which usually present a high activity at 300–400 °C.…”

Green shipping: Marine engine pollution abatement using a combined catalyst/seawater scrubber system. 1. Effect of catalyst

“…Notably, the issue of effects of high SO x content on the urea-SCR of diesel exhausts is usually not considered by researchers [21]. On the other hand, placing the SCR reactor after the scrubbing section would require reheating the exhausts which is energetically unacceptable.…”