(704g) Green Fuel from Hydrotreated Vegetable Oil Using Ni-Fe/Zeolite Y Catalysts

Developing sustainable and alternative energy is crucial to address the depletion of limited fossil resources and mitigate global warming. Hydrotreated vegetable oil, with similar structure to fossil fuels and ability to reduce carbon emissions, is considered as a potential alternative fuel.

In this work, the hydrotreatment of soybean oil for green fuel was conducted by Ni-Fe bimetallic supported on zeolite Y catalysts, denoted as Ni-Fe/Y, that were successfully synthesized with incipient wetness impregnation method. Prior to the process of hydrotreatment, the Ni-Fe/Y catalyst was firstly activated in hydrogen atmosphere at 400°C to a reduced state, denoted as Ni-Fe(R)/Y. Hydrotreatment of soybean oil was performed using decalin as the solvent and various Ni-Fe(R)/Y catalysts in a semi-batch reactor equipped with a magnetic stirrer and a temperature controller. Activated and spent catalysts were characterized by XRD, SEM, XPS, ICP-OES, H₂-TPR, NH₃-TPD, and N₂ physisorption analyzer. The determination of yield and selectivity of the product was accomplished by GC-FID, while qualitative analyses were conducted using GC-MS and FT-IR. Figure 1 illustrates the yield of deoxygenated hydrocarbons from soybean oil hydrotreated at 300°C and 40 bar H₂ with Ni-Fe/Y catalysts on which the total loadings of Ni and Fe on zeolite Y were fixed at 30 wt% based on the mass of zeolite Y. Compared to the Ni monometallic catalysts, the Ni-Fe/Y(R) catalyst with a mass ratio of Ni/Fe at 4 exhibited superior catalysis in deoxygenation and gave the larger overall yield. Additionally, increasing the total metal loadings and the reaction temperature can accelerate the reaction rate of deoxygenation and cracking, respectively. As a result, the hydrotreatment of soybean oil by 28Ni-7Fe(R)/Y catalyst at 350°C and 40 bar H₂ resulted in the best degree of deoxygenation and the highest yield in short-chain hydrocarbons. The reusability of the catalyst was also discussed in this work.