Kinetic Parameter Estimation of a Commercial Fe-Zeolite SCR

Abstract

In this work, an in-house computational code capable of simulating highly coupled physicochemical phenomena occurring in ammonia/urea SCR (selective catalytic reduction) was developed. On the basis of this computational code, the kinetic parameters of catalytic reactions were newly calibrated using the experimental results obtained over a commercial ammonia/urea SCR washcoated Fe-ion-exchanged zeolite-based catalyst. Powder-phase NH 3 TPD (temperature-programmed desorption) experiments were performed to calibrate the kinetic parameters of NH 3 adsorption and desorption, and core-out monolith experiments were conducted to estimate the kinetic parameters of various deNO x reactions as well as NH 3 oxidation. The currently established SCR model and kinetic parameters gave a good prediction for both steady-state and transient experimental results for a wide range of operating conditions. The main objectives of this study were to develop numerical tools and their implementation methodologies that can be cost-effectively applied to the design and development of real-world ammonia/urea SCR systems. Details of the procedures and techniques in numerical modeling and kinetic parameter calibration are described step-by-step in this article.

The Effect of Copper Loading on the Selective Catalytic Reduction of Nitric Oxide by Ammonia Over Cu-SSZ-13

“…9). From the slope of the plot, an apparent activation energy of *41.2 kJ/mol can be estimated for the NO reduction by NH 3 (''standard'' SCR) over Cu-SSZ-13, which is in line with the values obtained for various zeolite-based SCR catalysts (e.g., 29-89 kJ/mol) [14][15][16][17].…”

“…11. The apparent activation energy of *57.6 kJ/mol for NO oxidation over Cu-SSZ-13 can be estimated from this plot, and it is somewhat higher than those obtained previously for other zeolite-based SCR catalysts (e.g., 24-48 kJ/mol) [13,[15][16][17].…”

Improved high-temperature hydrothermal stability of Cu-SSZ-13 by an ammonium hexafluorosilicate treatment

“…The scanning rate was 3 per min within a 2q value of 5-50 . The 27 Al chemical shis, given in parts per million (ppm), were reported relative to a 0.1 M aqueous Al(NO 3 ) 3 solution and the 29 Si chemical shis (ppm) were referenced to a Si(CH 3 ) 4 . For the TEM measurements, the samples were dispersed in ethanol and then dried on a holey carbon lm Cu grid.…”

“…Aer hydrothermal aging, the catalytic activity of Cu-S-0.5 was lower than Cu-S-1, but it was still better than the untreated Cu-SSZ-13 catalyst. On the other hand, AHFS treatment of the Cu-SSZ-13 catalyst induces Al from the Si(OSi) 2 (OAl) 2 structure to be replaced by Si to form the more stable Si(OSi) 3 (OAl) and Si(OSi) 4 structures, thus improving the hydrothermal stability of the Cu-SSZ-13 catalyst. 7 shows the N 2 adsorption-desorption isotherms and pore size distributions of the Cu-SSZ-13 and Cu-S-1 catalysts before and aer hydrothermal aging.…”

“…1 However, to meet emission standards, their use depends on the effective reduction of two primary diesel exhaust components: nitrogen oxides (NO x ) and particulate matter (PM). 3,4 A typical NH 3 -SCR aertreatment system includes a diesel particulate lter (DPF). 3,4 A typical NH 3 -SCR aertreatment system includes a diesel particulate lter (DPF).…”