Abstract:

The aromatization and isomerization performance of 1-heptene over Ni/SiO2, Ni/NaZSM-5, Ni/ZSM-5-P and Ni/ZSM-5-P-Fe was investigated at the conditions of catalytic hydrodesulfurization (T = 673 K, P = 1.5 MPa, WHSV = 5 h-1). The catalysts were prepared by loading nickel on the carriers by spraying method and were characterized by XRD, XRF, N2 adsorption-desorption and NH3-TPD, H2-TPR, and pyridine-FTIR techniques. The product distributions show that Ni/ZSM-5-P-Fe and Ni/ZSM-5-P exhibit a remarkable enhancement of aromatization and isomerization of 1-heptene compared with that of Ni/ZSM-5, resulting in increased yields of isomerized product, aromatics, and dry gas. The performance of Ni/ZSM-5-P-Fe is even better because it has more mid-strong acid center and Bronsted acid, indicating that the Bronsted acid promotes the aromatization and isomerization of 1-heptene. It is concluded that the synergetic effect of metallic active sites and appropriate acid sites on the bifunctional catalysts is in favor of the aromatization and isomerization of 1-heptene.

Key words: modified ZSM-5, 1-heptene, isomerization, aromatization, RON, desulfurization technology