Session: Technical Posters

Paper Number: 110167

110167 - Impact of Engine Oil Derived Species on the Performance of Cu-Sssz-13 Scr Catalysts 

Selective catalytic reduction of NO_X with NH₃ is demonstrated as an efficient process for the abatement of NO_X in diesel exhaust. The US Environmental Protection Agency (EPA) recently proposed a dual SCR system in which an additional small volume SCR catalyst was placed upstream of the other components of the exhaust after-treatment system, closer to the engine outlet, in order to further limit NOx emissions.¹ Cu-exchanged zeolites, especially the small pore zeolite with a Chabazite (CHA) topology, have been widely used as SCR commercial catalysts in diesel engine exhaust systems. However, in real world applications, Cu-CHA SCR catalysts still suffer from deactivation issues via hydrothermal aging and chemical poisoning.

Chemical poisoning is associated with different exhaust gas components, which may contain soot, sulfur, traces of engine oil and decomposed products of engine oil. These will accumulate with time and can cause catalyst deactivation. Significant efforts have been made to understand and reduce the impact of sulfur through thermal and chemical treatments. On the other hand, the poisoning of Cu-CHA due to ash or inorganic depositions derived from engine oil and biofuels is still challenging. Some studies have examined the effects of various metals and alkali metal poisoning on CHA catalysts, and most of these introduce the poisoning elements through an impregnation method.²

In this study, the engine oils were directly deposited on a commercial Cu-SSZ-13 catalyst using a simple dip method. The effect of thermal decomposition of the engine oil on the catalysts for SCR at different temperatures was evaluated. In addition to engine oils, the impact of the base oil and additives used in engine oil formulations was also studied. The obtained results show a reduction in the SCR activity of the catalyst treated with the oil’s additives, likely due to formation of ash/deposits that might block the SCR catalyst's pores and activity. Thermal gravimetric analysis (TGA) was performed to understand the thermal decomposition of the oils and their respective additives. Furthermore, ICP analysis was also conducted to investigate the presence of elements after thermal treatment. Through these complementary techniques, the impacts of the different oil components can be characterized.

References:

1.     Federal Register, Vol. 85, 2020, 3306-3330.

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Presenting Author: Poonam Rani University of Virginia

Presenting Author Biography: Poonam Rani received her bachelor’s and master’s degree from Department of Chemistry, Panjab University, India. She obtained her PhD degree in inorganic and organic-inorganic hybrid porous frameworks from Department of Chemistry, Indian Institute of Technology Ropar in 2019. From February 2020 to March 2022, she worked as a post doc. research fellow in Charles University, Czech Republic. Her research study includes developing of porous materials towards application in heterogeneous catalysis and biomass transformations. To pursue her research interest on zeolites, she moved to Chemical Engineering, University of Virginia. Currently, in May 2022. Presently, Poonam is studying how fuel and oil additive components impact the selective catalytic reduction (SCR) reaction over Cu/SSZ13. So far, she has a total of 16 SCI publications to her credits and 1 Indian patent.