Bio-gasoline and bio-naphtha production from catalytic cracking of linseed oil methyl ester over iron- and zinc-modified HZSM-5 and γ-Al2O3 catalysts in a fixed double-beds reactor

This study investigates the catalytic cracking of linseed oil methyl ester in producing bio-naphtha and bio-gasoline fuels. The process was conducted over two beds of catalysts, including HZSM-5 (HZ) and γ-alumina (AL), in a continuous reactor. The support catalysts were modified by zinc and iron metals with various loadings (4 wt% and 8 wt%) through the incipient wetness impregnation method and characterized by XRD, XRF, FESEM-EDS, N₂ adsorption-desorption, and NH₃-TPD analyses. These analyses demonstrated that the existence of metals altered the textural properties and the acid site distribution of support catalysts. The experiments were carried out at the Cat. Ratio (mass ratio of AL catalyst to total mass of AL & HZ catalysts) = 0.75, WHSV = 3 h⁻¹, T = 475 °C, P = 1 bara under N₂ atmosphere. The aim was to discuss the synergistic effect of using two modified catalyst beds in production of bio-naphtha and bio-gasoline. With this respect, the general factorial design approach was employed for the statistical evaluation of the bio-naphtha and bio-gasoline production yields. The results revealed that bio-naphtha could be produced with the yield of 42.3 wt% over the double catalyst beds comprising 4ZnHZ and AL. By using 4FeHZ & AL in series, 39.0 wt% yield of bio-naphtha could be achieved. According to the bio-gasoline yield, Fe and Zn loading value of 4 wt% is the most suitable, i.e. 90.3 wt% yield on 4FeHZ-4FeAL, and 89.5 wt% yield on 4ZnHZ-4ZnAL can be obtained.