Combined use of a mass-spectrometer and a UV analyzer in the dynamic study of NH3-SCR for diesel exhaust aftertreatment

Abstract

A mass spectrometer (MS) and a novel UV analyzer were coupled in the experimental study of the transient Selective Catalytic Reduction (SCR) reactivity, aimed at the development of a dynamic numerical model of SCR converters for the selective reduction of NO x in Diesel exhausts. Their parallel use revealed an effective method for the understanding of key elements in the SCR reaction mechanism under real operating conditions.

Kinetic Modeling of Dynamic Aspects of the Standard NH3-SCR Reaction Over V2O5-WO3/TiO2and Fe-Zeolite Commercial Catalysts for the Aftertreatment of Diesel Engines Exhausts

“…The monolith catalysts were crushed and ground to powder (140-200 mesh), a sample of powder (160 mg for vanadium-based and 80 mg for Fe-zeolite catalysts) was diluted with 80 mg of quartz and loaded in a flowmicroreactor consisting of a quartz tube (6 mm i.d.) directly connected both to a UV analyzer (ABB Limas 11-HW) and to a quadrupole mass spectrometer (Balzers QMS 200), which operated in parallel [14].…”

“…The presented models implement kinetic schemes derived from an extensive investigation of reactivity, chemistry and catalytic mechanism of all the main SCR reactions over commercial V 2 O 5 -WO 3 /TiO 2 and Fe-zeolite catalysts performed in our laboratories during the last few years [2][3][4][5][6][7][8][9][10][11][12][13][14].The related rate expressions were fitted to transient data collected over powdered catalysts in the chemical regime, and in their global form allow the kinetic analysis of the full NH 3 -NO/NO 2 SCR reacting system.…”

Dynamic Methods in Catalytic Reaction Engineering: Applications to the Investigation of the NH3 Selective Catalytic Reduction Reactions for Diesel Emission Control

“…Relevant interferences in the mass-to-charge signals were taken into account in determining the products composition. To improve the time resolution for the continuous analysis of reactants and products, a UV analyzer, (ABB Limas11 HW) able to detect simultaneously NH 3 , NO, and NO 2 was coupled with the MS in a parallel arrangement …”

Unifying redox kinetics for standard and fast NH3‐SCR over a V2O5‐WO3/TiO2 catalyst

“…For the purposes of this study new unsteady kinetic NH 3 ‐SCR experiments of different nature were performed over the same commercial extruded V 2 O 5 ‐WO 3 /TiO 2 catalyst with medium‐high V‐content investigated in previous work,19–29 originally supplied by Daimler as an extruded honeycomb monolith. Experimental details have been already reported elsewhere 19, 28.…”

“…Briefly, the catalyst was ground to powder (140–200 mesh), a sample (160 mg) was diluted with 80 mg of quartz and loaded in a flow‐microreactor consisting of a quartz tube (6 mm i.d.) directly connected both to a UV analyzer (ABB Limas 11‐HW) and to a quadrupole mass spectrometer (Balzers QMS 200), which operated in parallel 29…”