Development of High-Throughput Catalyst Screening For Ammonia Based Selective Catalytic Reduction of Nitric Oxide With Parallel Analysis Using Fourier Transform Infrared Imaging

Publication Year:
2013
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Repository URL:
https://scholarcommons.sc.edu/etd/2448
Author(s):
Salim, Shahriar
Tags:
Chemical Engineering; Engineering
thesis / dissertation description
Lean-burn engines, which operate under excess air to fuel ratio offer significant fuel efficiency as well as contribute to the reductions of greenhouse gas emissions. However, lean burn engines produce three main pollutants carbon monoxide (CO), nitrogen oxides (NOx) and unburned or partially burned hydrocarbons (HC), which have detrimental effect on both environment and human life. The conventional three way catalyst (TWC) which was designed to reduce NOx under stoichiometric conditions is not effective under lean-burn engine exhaust condition. Recent studies have shown that copper (Cu) exchanged chabazite (CHA) type zeolites are very promising catalysts for urea or ammonia (NH3) based selective catalytic reduction (SCR) of NOx and expected to meet with our future needs, due to their low temperature activity and high hydrothermal stability.High-throughput experimentation (HTE) is an active area of interest in the field of catalysis due to its potential in optimization of time and cost. Fourier transform infrared (FTIR) imaging is a powerful spectroscopic tool which combines the chemical sensitivity of infrared spectroscopy with the ability to rapidly analyze multiple samples simultaneously. A large number of heterogeneous catalysts can be tested under realistic condition using a high-throughput parallel reactor (HTR) and the product gases can be analyzed quantitatively in parallel simultaneously using FTIR imaging technique.The objective of this research is to develop high-throughput catalyst screening for NH3 based SCR of NOx. High throughput methodology (HTM) will allow us to perform a significant number of experiments in a short period of time and will be beneficial for comparison of activity and selectivity of a significant number of catalysts. The first chapter of the thesis summarizes the motivation as well as the present NOx reduction methods and limitations of those methods. It also summarizes the progresses of HTM for parallel testing of catalysts under realistic conditions.The second chapter provides the detail of the 16 channel HTRs (Primary and Secondary screening reactor) used to test the 16 powdered catalysts under plug flow condition. It also provides the detail of FTIR imaging system built for the parallel analysis of the reaction product gases. A brief description of chemometrics for quantitative infrared spectral analysis is also included. Lastly, this chapter summarizes the catalyst synthesis and characterization techniques used in this research.The third chapter details the experimental results of CO oxidation reaction. It summarizes the calibration results of CO and carbon dioxide (CO2). It also provides the results of catalyst screening for CO oxidation reaction using the primary screening reactor (PSR) along with the results of characterization of catalysts used to study CO oxidation reaction.The fourth chapter details the experimental results of NH3 based SCR of nitric oxide (NO). It summarizes the univariate and multivariate calibration results used for NH3 based SCR reaction study. It also provides the results of benchmark reaction and catalyst screening using the secondary screening reactor (SSR).The last chapter provides a perspective of this research and recommendations for the direction of future works.