Green diesel production through simultaneous deoxygenation of palmitic acid and desulfurization of 4,6-Dimethyl-dibenzothiophene over commercial CoMo/Al2O3

Sunya Boonyasuwat,Jirdsak Tscheikuna

doi:10.18331/brj2018.5.2.6

Abstract

This study investigated the deoxygenation of palmitic acid as a model compound of palm fatty acid distillate (PFAD), in the presence of 4,6- di-methyl-di-benzothiophene as a sulfur-containing light gas oil (LGO). Reactions were performed at the pressure of 25 barg, liquid hourly space velocity (LHSV) of 1.7 h-1, and H2/oil of 630 NL/L over CoMo/Al2O3 as catalyst. The effect of temperature was studied in the range of 275-300 oC. Both deoxygenation and desulfurization led to approximately 100% conversions at 300 oC, while at 275 oC, palmitic acid deoxygenation was recorded at a higher conversion rate compared with that of the desulfurization of 4,6- di-methyl-di-benzothiophene. The presence of 4,6- di-methyl-di-benzothiophene during the deoxygenation of palmitic acid resulted in high conversions (>95%). Pressure drop studies showed that the formation of heavy products caused a gradual pressure drop throughout the reactor over time. The catalyst was deactivated during 10 d. Two different sulfur-containing reagents were used for catalyst reactivation including dimethyl-disulfide in n-C18 and LGO containing 484 ppmw of sulfur. Reactivation with 2 wt.% of dimethyl-disulfide in n-C18 at 320 oC for 36 h led to more favrable performance recovery vs. the sulfur-containing LGO.

Highlights

In recent decades, unpredictable crude oil prices and the consequent environmental issues attributed to the widespread utilization of these resources have encouraged large demands for cleaner alternative fuels (Huber et al, 2006)
The catalyst used in this study was a commercial hydrotreating catalyst, CoMo/Al2O3 and was the same as the one used in our previous work (Boonyasuwat and Tscheikuna, 2017)
The catalyst used in this study was a commercial CoMo/Al2O3, which was used in our previous work for pilot-scaled production of green diesel by co-processing palm fatty acid distillate (PFAD) and light gas oil (LGO) (Boonyasuwat and Tscheikuna, 2017)

Summary

Introduction

Unpredictable crude oil prices and the consequent environmental issues attributed to the widespread utilization of these resources have encouraged large demands for cleaner alternative fuels (Huber et al, 2006). The EUs Renewable Energy Directive (RED) launched a policy to further stimulate the increase in production and promotion of energy from renewable sources to 900 million tons accounting for 20 wt.% biofuel in fuel blends by the year 2020. In order to reach the aim of the RED proposal, various kinds of waste materials have been recently investigated for the production of biofuels, i.e., second-generation biofuels. These have been known as advanced biofuels synthesized from biomass, agricultural residues, and wastes, e.g. lingocellulosic ethanol, pyrolysis of biomass to bio-oil, and hydrogenation of fats and oils to diesel-like hydrocarbons

Methods

Results

Conclusion