The stabilization of bio-oil as an alternative energy source through hydrodeoxygenation using Co and Co-Mo supported on active natural zeolite

Abstract

In this study, hydrodeoxygenation (HDO) process of bio-oil from coconut shell waste was catalyzed by active Sarulla natural zeolite (ZAS) supported by Co metal and a combination of Co-Mo metal. The resulting bio-oil HDO product is expected to have good physicochemical stability during the storage period so as to increase its potential as an alternative source of hydrocarbon energy. Preparation and activation of ZAS catalyst with 3M HCl and calcination with N2 gas flow. Impregnation of Co and Co-Mo into ZAS was carried out by wet impregnation method followed by oxidation and reduction with O2 and H2 gas flow. Several important properties of the catalyst were characterized by XRD, SEM, FTIR, and BET methods. Bio-oil HDO process is carried out in fixed bed reactor with H2 gas flow at a certain temperature for two hours. Analysis of physicochemical properties and stability of bio-oil products includes analysis of acid number, viscosity, elementary content, HHV, and component analysis using GC-MS. The data obtained showed that the loading of two metals increased the spesific surface area, volume and pore size, but decreased the crystallinity of the catalyst. Based on the distribution of HDO products, it indicates that monometal catalysts tend to produce more liquid phase, coke, and gas while bimetallic catalysts tend to produce more organic phase. Viscosity and acid number of bio-oil catalyzed by Co-Mo/ZAS is lower than that of Co/ZAS. Co/ZAS catalyst showed high selectivity towards the aqueous phase. The bio-oil catalyzed by Co/ZAS has a higher HHV and a higher viscosity and lower oxygen content as a result of the release of hydrogen bound oxygen into water molecules. Thus, it can be assumed that the deposition of Co and Co-Mo on zeolite has a different effect on the characteristics of zeolite and its activity as a catalyst.