Fabrication and characterization of ZSM-5 zeolite modified with silver and assessing its performance in petroleum waste cracking process

Abstract

The purpose of this study is to modify the structure of ZSM-5 zeolite with the aim of enhancing its performance in the cracking process for the conversion of petroleum waste into higher-value products. ZSM-5 zeolite was synthesized using a microwave-assisted hydrothermal method subsequently, the structure of the zeolite was modified by incorporating silver using the incipient wetness impregnation method. Then the synthesized sample was evaluated for its performance in a fluid catalytic cracking (FCC) process, conducted under atmospheric pressure and at a temperature of 450 °C. The performance of the silver-doped ZSM-5 zeolite was compared to that of a basic catalyst, which employed USY (ultra-stable Y) zeolite. To characterize the silver-doped ZSM-5 zeolite, various analytical techniques were employed. These included X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR), temperature-programmed desorption of NH3 (NH3-TPD) and N2 adsorption–desorption. The findings of the study revealed that the modification of ZSM-5 zeolite's structure with silver led to an increase in the yield of propylene production from 6.99 % to 9.78 %. Additionally, the results demonstrated that the incorporation of silver into the zeolite structure enhanced the yield reaction, as evidenced by the measurement of American Petroleum Institute (API) index. The presence of smaller pores and the specific types of pores in Ag/ZSM-5 zeolite reduced secondary reactions. Moreover, the interaction between silver species and strong acid sites within the modified zeolite structure limited hydrogen transfer reactions and consequently increased the zeolite's overall activity.