High Acidity and Low Carbon-Coke Formation Affinity of Co-Ni/ZSM-5 Catalyst for Renewable Liquid Fuels Production through Simultaneous Cracking-Deoxygenation of Palm Oil

Abstract

This study investigates the effect of chemically doped Co and Ni metals on ZSM-5 catalyst with respect to the cata-lysts' characteristics and performance for palm oil cracking. Some characterization methods have been conducted to identify the physicochemical properties of the synthesized catalysts, including X-ray diffraction (XRD), Scan-ning Electron Microscopy (SEM), N2-physisorption, NH3- and CO2-probed Temperature Programmed Desorption (NH3-TPD and CO2-TPD) methods. The deposited carbon-coke on the spent catalysts is analysed using simultane-ous thermal gravimetric-differential scanning calorimetry (TG-DTG-DSC) analysis. The performance of catalysts was evaluated on palm oil cracking process in a continuous fixed-bed catalytic reactor at 450 °C. To determine the liquid product composition functional group and components, we used Attenuated Total Reflectance Fourier-transform Infrared Spectroscopy (ATR-FTIR) and batch distillation methods, respectively. We found that the Co metal chemically-doped on Ni/SM-5 catalyst, resulting the increase in the catalysts acidity and the decrease in cat-alysts basicity. The conversion of palm oil increases as the increase of the ratio of catalysts' acidity to basicity. The highest triglyceride conversion (76.5%) was obtained on the 3Co-Ni/ZSM-5 with the yield of gasoline, kerosene, and diesel of 2.61%, 4.38%, and 61.75%, respectively. It was also found that the chemically doping Co metal on Ni/ZSM-5 catalyst decreased carbon-coke formation due to the low catalysts' basicity. Overall, it is proven that the combination of Co and Ni, which chemically doped, on ZSM-5 catalyst has a good activity in palm oil conversion with low carbon-coke formation affinity and high acidity of catalyst.