Investigation of Effective Parameters Ce and Zr in the Synthesis of H-ZSM-5 and SAPO-34 on the Production of Light Olefins from Naphtha

Omer Dhia Aldeen Salah Aldeen,Hasan Sh Majdi,Ehsan Kianfar,Dhameer A Mutlak,Mustafa Z Mahmoud,Khusniddin Fakhriddinovich Uktamov,Zhongchang Wang

doi:10.1155/2022/6165180

Abstract

In this paper, Ce and Zr modified commercial SAPO-34 and H-ZSM-5 catalysts were synthesized via a wet impregnation method and used as catalysts for the production of light olefins from naphtha. The synthesized catalysts were characterized using SEM, TGA, XRD, BET, and NH3-TPD. Thermal catalytic cracking of parent catalysts (SAPO-34 and H-ZSM-5) and modified catalysts with Ce and Zr on the production of light olefins from naphtha has been studied. The effects of different loading of Ce (2–8 wt.%), Zr (2–5 wt.%), and different temperatures on the yield of ethylene and propylene were also investigated. The yield of ethylene and propylene improved by 21.78 wt% and 23.8 wt%, respectively, over 2% Ce and 2% Zr on SAPO-34 catalyst. This is due to the higher acid sites on the surface of modified catalysts. It was found that H-ZSM-5 with 2% Zr loading has the highest yield of light olefins (40.4%) at 650°C in comparison with unmodified parent catalysts, while Ce loading has less effect on the olefin yield compared to Zr loading. Finally, simultaneous loading of Ce and Zr showed no effect on the light olefin yield owing to the significant decline of acid sites.

Highlights

Light olefins, such as ethylene and propylene, are important raw materials for synthesizing many organic compounds in the industry in a huge volume including plastics, synthetic fibers, and rubber
We investigate the impact of Ce and Zr modified H-ZSM-5 and SAPO-34 catalysts on the production of light olefins from naphtha. e chemical structure, morphology, surface area, surface acidity, and structure stability for the catalyst are studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 adsorption-desorption isotherms, ammonia probe-temperature programmed desorption (NH3-TPD), and thermogravimetric analysis. e catalyst activities during the cracking of naphtha are tested using a pilot thermal catalytic cracking
According to the NH3-TPD analysis results, the strong acidity of the catalysts increased by 2% Ce-2% Zr/ SAPO-34 > 2% Ce/SAPO-34 > 2% Zr/SAPO-34> SAPO-34, respectively, and the reactor results show the same ranking in ethylene and propylene yields, with SAPO-34 having the lowest yield and 2% Ce-2% Zr/SAPO-34 having the highest yield of light olefins

Summary

Introduction

Light olefins, such as ethylene and propylene, are important raw materials for synthesizing many organic compounds in the industry in a huge volume including plastics, synthetic fibers, and rubber. Aluminum silicate is a good example of catalyst used in catalytic fluidized bed cracking (FCC), and it has a threedimensional crystalline structure with regular cavities of molecular size [27,28,29,30,31,32,33] Zeolite catalysts such as ZSM-5 and SAPO-34 have been widely used in the oil refining, petrochemical, and pollution control industries [29, 34,35,36,37,38,39,40,41,42,43]. We investigate the impact of Ce and Zr modified H-ZSM-5 and SAPO-34 catalysts on the production of light olefins from naphtha. e chemical structure, morphology, surface area, surface acidity, and structure stability for the catalyst are studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 adsorption-desorption isotherms, ammonia probe-temperature programmed desorption (NH3-TPD), and thermogravimetric analysis. e catalyst activities during the cracking of naphtha are tested using a pilot thermal catalytic cracking

Experimental

Results and Discussion

Catalyst Performance

90 HZSM-5

Conclusion