Removal of sulfur compounds from diesel using ArF laser and oxygen

Abstract

A laser-based technique for deep desulfurization of diesel and other hydrocarbon fuels by removal of dimethyldibenzothiophene (DMDBT), a persistent sulfur contaminant in fuel oils has been developed. We report a selective laser excitation of DMDBT in diesel and model compounds such as n-hexane in a reaction chamber under oxygen environment where oxidative reactions can take place. ArF laser emitting at 193 nm was employed for excitation of oxygen and DMDBT, while for process optimization, the laser energy was varied from 50 to 200 mJ/cm². The laser-irradiated DMDBT solution under continuous oxygen flow was analyzed by UV absorption spectrometer to determine the photochemical oxidative degradation of DMDBT. In just 5 min of laser irradiation time, almost 95% DMDBT was depleted in a diesel containing 200 ppm of DMDBT. This article provides a new method for the removal of sulfur compounds from diesel by laser based photochemical process.

Keywords:

• Sulfur removal
• clean fuels
• DMDBT
• photo-oxidation
• laser applications

Acknowledgments

The financial support provided by King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia through Project No. DRP-4-25 and facility support provided by the King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia for this work are gratefully acknowledged.