Investigation of NH3 and no adsorption over Cu/SAPO-34 and Cu/AlOo3 catalysts for NH3–SCR system

Author

Basil Rawah, New Jersey Institute of Technology

Document Type

Thesis

Date of Award

Spring 5-31-2017

Degree Name

Master of Science in Chemical Engineering - (M.S.)

Department

Chemical, Biological and Pharmaceutical Engineering

First Advisor

Xianqin Wang

Second Advisor

R. P. T. Tomkins

Third Advisor

Robert Benedict Barat

Abstract

In this study, Copper supported on SAPO-34 molecular sieves or alumina is prepared via an incipient wetness impregnation method for ammonia selective catalytic reduction (NH₃-SCR). These NH₃-SCR catalysts are characterized by pulse chemisorption, temperature-programmed reduction (TPR), and temperature-programmed desorption (TPD) with three different conditions (NH₃, NO, combined NH₃-NO) to evaluate the adsorption of ammonia and nitric oxide. Cu/SAPO-34 catalyst has shown higher ammonia adsorption capacity compared to Cu/Al₂O₃ catalyst. The Cu/SAPO-34 adsorption is enhanced due to the strong acidity and high surface area of SAPO-34 molecular sieves. NO adsorption peaks over both catalysts are small (for NO-TPD) and these peaks become broader when a combined NH₃-NO is introduced to the system.

However, Cu/SAPO-34 & Cu/Al₂O₃ surface area and acidity are decreased dramatically comparing to SAPO-34 and Al₂O₃ supports. These observations are verified by TPR and CO chemisorption. The formation of bulk copper aluminate over (Cu/Al₂O₃) surface and CuO over (Cu/SAPO-34) surface may block the acid sites. Moreover, the metal dispersion over both catalysts is below 10%.

Based on the comparison, various factors could influence the adsorption of NH₃ and NO over the catalyst surface. The high specific surface area could provide abundant adsorption sites, which increase the adsorption capacity. Also, the multiple locations of acid spots along a wide temperature range, which are seen over Cu/SAPO-34, could continuously maintain the adsorption of NH₃ and NO even at elevated temperature.

Recommended Citation

Rawah, Basil, "Investigation of NH3 and no adsorption over Cu/SAPO-34 and Cu/AlOo3 catalysts for NH3–SCR system" (2017). Theses. 27.
https://digitalcommons.njit.edu/theses/27