The effect of hydrogen flow rate and temperature on hydrodeoxygenation of oleic acid over Ni/MOR catalysts

Abstract

This work investigated the effect of hydrogen flow rate and temperature on hydrodeoxygenation (HDO) of oleic acid over Ni-supported mordenite catalysts. The Ni/MOR catalysts were prepared using the wet impregnation method and characterized using SAA (surface area analyzer) and NH3-TPD (temperature-programmed desorption). The HDO tests of oleic acid were conducted in a semi-flow reactor within a hydrogen flow rate of 10, 15, and 20 mL/minute and a temperature of 300, 350, and 400 °C. The liquid products were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS) to identify the composition of the products. The results showed that oleic acid was converted into hydrocarbons with high yields. Ni/MOR catalysts can increase the conversion of oleic acid compared to thermal reactions. Nevertheless, the hydrogen flow rate and temperature significantly influence the conversion of oleic acid. 15 mL/min was the preferred hydrogen flow rate for the HDO reaction of oleic acid, which provides the highest conversion of 93 %. On the other hand, the oleic acid conversion was slightly decreased with an increase in temperature. Heptadec-8-ene is the main product obtained by decarboxylation of oleic acid. Furthermore, C4-16 hydrocarbons were also obtained due to the cracking reaction promoted by an increase in temperature.