Mixing assisted oxidative desulfurization using a synthesized catalyst of the activated carbon supported phosphotungstic acid: A process optimization study

• Published in: South African journal of chemical engineering 2022-10, Vol.42, p.61-71
• Main Authors: Barilla, Gerje Ronelle H., Chen, Charles Adrian W., Valencia, Martin Zechariah M., Dugos, Nathaniel P., Choi, Angelo Earvin Sy
• Format: Article
• Language: English
• Subjects: Activated carbon; Analysis; Diesel oil; Fuel oil; Impregnation method; Mixing assisted oxidative desulfurization; Optimization analysis; Phosphates; Phosphotungstic acid; Thiophene; Tungsten compounds
• ISSN: 1026-9185
• DOI: 10.1016/j.sajce.2022.06.012

•Actual diesel oil was mixed with benzothiophene and dibenzothiophene.•Activated carbon supported phosphotungstic acid was successfully synthesized.•The most significant variable was the mixing time and mixing temperature.•Optimum sulfur conversion was achieved at 88.5 min, 16,800 rpm and 63.28°C. Desulfurization technology is vital in the removal of sulfur compounds in diesel to attain clean fuels. In this research, the mixing assisted oxidative desulfurization (MAOD) in conjunction with a high shear mixer was used with the catalyst of the activated carbon supported phosphotungstic acid. This study discusses the desulfurization of a simulated diesel, containing 2.3 wt% S of dibenzothiophene and benzothiophene in real fuel oil. The influences of mixing speed (8,000 rpm to 16,800 rpm), mixing time (30 min to 90 min), and mixing temperature (25°C to 65°C) were examined for the sulfur oxidation. A 2k full factorial design and a face-centered cube design were utilized for the screening and optimization studies, respectively, in the experimental runs. The analysis of variance was able to determine and generate a simplified quadratic model to predict the response in the MAOD process. The optimum variables for sulfur conversion were achieved at 88.5 min (mixing time), 16,800 rpm (mixing speed), and 63.28°C (mixing temperature). The confirmatory run resulted in percent oxidation of 62.37 % and validated the generated model. Moreover, the fundamental properties of diesel oil were analyzed for comparison prior to and after the MAOD method. The results revealed the retention of essential properties of the simulated diesel oil even after the MAOD treatment step. Thus, the MAOD process has successfully preserved the properties of diesel oil even after its treatment process. This indicates a promising result of the MAOD process favorable for its future applications.