A Deep Desulfurization Process for Light Oil by Photosensitized Oxidation Using a Triplet Photosensitizer and Hydrogen Peroxide in an Oil/Water Two-Phase Liquid−Liquid Extraction System

Abstract

A deep desulfurization process for light oil has been investigated, on the basis of photosensitized oxidation using a triplet photosensitizer and hydrogen peroxide in an oil/water two-phase liquidliquid extraction system. Dibenzothiophene (DBT) in tetradecane was effectively desulfurized. This was achieved via the indirect photoexcitation of DBT, using benzophenone (BZP) under photoirradiation conditions of wavelength λ > 280 nm, and the effective oxidation of the excited DBT by H 2 O 2 , suppressing the photodecomposition of H 2 O 2 . The desulfurization of commercial light oil was also achieved in this process by the addition of both BZP and H 2 O 2 , and the sulfur content was reduced from 0.2 to 0.05 wt % by 48 h of photoirradiation, to meet with the new regulation in Japan. Although C5 and C6 alkyl-substituted DBTs were found to be the most difficult components to be desulfurized, they too were desulfurized effectively in the presence of BZP and H 2 O 2 . The photodecomposed sulfur-containing compounds removed into the water phase were separated successfully, using column adsorption with aluminum oxide as the adsorbent. The H 2 O 2 solution recovered is also reusable for the desulfurization process.

Oxidative processes of desulfurization of liquid fuels

“…45 Under these conditions, the desulfurization of commercial light oil was also achieved and the sulfur content was reduced from 0.2 to 0.05 wt % by 48 h photo-irradiation. But this long reaction time makes this process not applicable at an industrial level.…”

“…[44][45][46][47] This compound is excited under light radiation and then activates the sulfur compound, and these excited compounds are then oxidized by the hydrogen peroxide.…”

Heterogeneous Photocatalytic Reactions of Sulfur Aromatic Compounds

“…[76] This work is a continuation of research on photocatalytic oxidation of thiophenes using BZP as a homogeneous photosensitizer in a water/organic liquid extraction system. [115] The sensitization efficiency of the BZP/silica gel is lower than that of BZP in solution. Nevertheless, indirect photoexcitation of DBT by BZP/ silica gel and subsequent oxidation by H 2 O 2 proceeds effectively; unfortunately, molecular products of photooxidation are not reported.…”

Utilisation of factorial experiments for the UV/H2O2 process in a batch reactor

“…Over the last decade several studies have been conducted on the performance of hydrogen peroxide (H 2 O 2 ) and ultraviolet (UV) light in an advanced oxidation process (AOP) which has been successfully utilised for the treatment of various refractory (Doré, 1989;Sundstrom et al, 1990;Legrini et al, 1993;Sapach and Viraghan, 1998;Ho and Bolton, 1998;Von Gunten and Oliveras (1997); Shiraishi et al, 1999;Wenzel et al, 1999;Huston and Pignatello, 1999;Ince, 1999;Wang and Hong, 1999;Andreozzi et al, 2000a;Chiron et al, 2000). These previous studies have given the effect of initial H 2 O 2 concentration, initial concentration of the recalcitrant pollutants, and of time and UV light on the performance of the AOP process.…”