Modelling the Hydrothermal Ageing of a Fe‐Zeolite Catalyst for Automotive NH₃‐SCR Applications

Abstract

The effects of duration and temperature of hydrothermal ageing treatments were investigated on a commercial Fe‐zeolite catalyst for NH3‐SCR addressing NH3 adsorption, NH3 oxidation, and NH3 reaction with NOx. Hydrothermal ageing affected primarily NH3 oxidation and standard SCR activities, as well as NH3 storage capacity. Deactivation was fast in the first few hours, eventually approaching asymptotic levels. There is potential to predict the effects of hydrothermal ageing on the SCR behavior of Fe‐zeolite catalysts as a function of just one parameter, i.e., the NH3 storage capacity.

An Overview of Lean Exhaust deNOx Aftertreatment Technologies and NOx Emission Regulations in the European Union

“…In this latter work, a model accounting for hydrothermal ageing of the involved catalysts has been included permitting, in the end, the investigation of the optimal design of the system by optimizing line geometry and catalyst location as a function of the foreseen degree of ageing, based on the simulation output. In general, hydrothermal ageing in metal-exchanged zeolites has been extensively studied in the literature and simulated according to relatively simple approaches such as tuning the NH 3 storage capacity, depending on the ageing conditions [126]. Nevertheless, as shown in the literature, it is clear from the investigation of field-aged heavy-duty catalysts that is important to account, among other effects, for the deposition of chemical elements contained in the fuel, the impact of the lube oil, and the engine wear [127,128].…”

Preparation of zeolite type faujasite from glass waste and aluminum scraps for the selective catalytic reduction of NO with NH3

“…Around 2005, NH 3 -SCR technology using V-catalysts was introduced for heavy duty (HD) diesel vehicles in Europe [13] Nevertheless, some disadvantages like the rapid decrease in activity and selectivity at temperatures above 550 °C [14][15][16] as well as the toxicity of vanadium species, which volatilize at temperatures above 650°C [ 17,18], prompted the development of new types of catalysts. Among them, zeolites exchanged with copper and iron [14][15][16] are active over a wider temperature range than catalysts based on vanadium oxide and are less selective for N 2 O. Besides, they have very low NH 3 release and some sulfur tolerance.…”

Selective catalytic reduction of NO by NH3 on cerium modified faujasite zeolite prepared from aluminum scraps and industrial metasilicate

“…Moreover, it shows high oxidation of SO 2 to SO 3 which leads to decrease the activity and selectivity of NO x at 400°C [8][9][10]. For these reasons, copper and iron exchanged zeolites have been developed and are preferred for mobile Diesel sources [11][12][13]. In the last decades, the cerium-catalysts were investigated in the NH 3 -SCR of NO because of its redox property (Ce 3+ to Ce 4+ ) that promotes the activation of reactants on the surface of the catalysts [14,15].…”