Application of PdCe-HMOR Catalyst as NOx CH4-SCR System for Heavy-Duty Vehicles Moved by Natural Gas

Abstract

In this work a cobalt-free zeolite-based catalyst formulation is proposed for NO x CH 4 -SCR towards a commercial application of after-treatment system for heavy-duty vehicles moved by natural gas (lean-gas burn engines). PdCe-HMOR catalyst was characterised by H 2 -TPR, DRS UV-Vis and TEM/EDS. The effect of [CH 4 ]/ [NO] in the gas feed was studied in order to assess the catalytic performance under simulated dynamic engine conditions. The catalyst was also tested with a representative gas feed of real exhaust gases of a heavy-duty vehicle's engine (lean-burn conditions) powered by natural gas.

Optimizing Washcoating Conditions for the Preparation of Zeolite-Based Cordierite Monoliths for NOx CH4-SCR: A Required Step for Real Application

“…For instance, with about 1 g of starting material (NH 4 MOR), it is possible to obtain enough catalyst for all characterization techniques and catalytic tests, these lasts requiring ca. 200 mg. − For preparing a monolith (with dimensions D × L = 1 × 1 in. 2 ), at least ca.…”

“…In this study, a bimetallic Pd–Ce–Zeolite was used for monoliths preparation. This sample was prepared by using as support a NH 4 MOR commercial zeolite (CBV21A, Si/Al = 10, Zeolyst) and following the procedure reported and optimized in previous works. − In summary, a certain mass of the parent zeolite was ion-exchanged with a Pd­(NH 3 ) 4 (NO 3 ) 2 aqueous solution (Aldrich, 99.99%) for 24 h, at room temperature, in order to introduce 0.3 wt % Pd. Afterward, the catalyst was centrifuged and dried overnight.…”

“…This sample was then impregnated with a solution of Ce­(NO 3 ) 3 (Fluka, 99%), in order to introduce 2 wt % Ce. After drying overnight, the catalyst was calcined at 500 °C (5 °C/min), for 8 h. The final sample was named as Pd(0.3)­Ce(2.0)-HMOR and information regarding its main properties and performances can be found in previous works. , …”

“…In a first approach, the effect of the milling time in the zeolite particle size distribution and viscosity as well as the influence of the zeolite slurry concentration in the total catalyst load washcoated on the monolith were assessed. On the basis of these preliminary studies and the data reported in the literature, a washcoating procedure was defined using cordierite monolithic supports with 400 and 600 CPSI and a bimetallic zeolite catalyst optimized in our former works (Pd(0.3)­Ce(2.0)-HMOR − ).…”

Chemical Vapour Deposition (CVD) Technique for Abatement of Volatile Organic Compounds (VOCs)

“…A challenge for the 21st century is the control of technological processes in all industries to develop atom-economical and environmental friendly processes without by-products [8][9][10][11][12][13]. In this context, excellent comparative studies for several catalysts have been performed to improve catalytic performance in catalytic removal of CH4, NOx, COx, VOCs from flue gases [14][15][16][17][18][19][20][21][22]. VOCs are known as organic compounds with a low boiling point (≤ 250°C) at atmospheric pressure, according to the European Union (EU) [23].…”