Kinetic and Performance Studies of the Regeneration Phase of Model Pt/Ba/Rh NOx Traps for Design and Optimization

Harold, Michael ; Balakotaiah, Vemuri

University of Houston System

关键词: Nitrogen Oxides;    Platinum;    Exhaust Gases;    Barium;    Regeneration;   

DOI  :  10.2172/1004579
RP-ID  :  FC26-05NT42630
RP-ID  :  1004579

美国|英语

来源: UNT Digital Library

【 摘 要 】

In this project a combined experimental and theoretical approach was taken to advance our understanding of lean NOx trap (LNT) technology. Fundamental kinetics studies were carried out of model LNT catalysts containing variable loadings of precious metals (Pt, Rh), and storage components (BaO, CeO{sub 2}). The Temporal Analysis of Products (TAP) reactor provided transient data under well-characterized conditions for both powder and monolith catalysts, enabling the identification of key reaction pathways and estimation of the corresponding kinetic parameters. The performance of model NOx storage and reduction (NSR) monolith catalysts were evaluated in a bench scale NOx trap using synthetic exhaust, with attention placed on the effect of the pulse timing and composition on the instantaneous and cycle-averaged product distributions. From these experiments we formulated a global model that predicts the main spatio-temporal features of the LNT and a mechanistic-based microkinetic models that incorporates a detailed understanding of the chemistry and predicts more detailed selectivity features of the LNT. The NOx trap models were used to determine its ability to simulate bench-scale data and ultimately to evaluate alternative LNT designs and operating strategies. The four-year project led to the training of several doctoral students and the dissemination of the findings as 47 presentations in conferences, catalysis societies, and academic departments as well 23 manuscripts in peer-reviewed journals. A condensed review of NOx storage and reduction was published in an encyclopedia of technology.