Desulfurization of oxidized diesel fuel in a spiral micro-channel contactor under ultrasound irradiation

The extractive desulfurization of the oxidized real diesel fuel has been investigated in a spiral micro-channel contactor. The solvent screening has been performed and dimethylformamide has demonstrated the best performance in sulfur removal and fuel recovery. In addition, the influence of channel size, channel length, sonication intensification approach, and multi-stage extraction on the sulfur removal have been studied. It was found that the desulfurization efficiency increased from 42.94% to 70.25% as the channel size decreased from 1.78 mm to 0.79 mm, which is due to the higher interfacial area in the smaller channel diameter. Also, the results showed that increasing the micro-channel length from 160 mm to 640 mm increased the sulfur removal from 52% to 85%, respectively. Moreover, the simultaneous effect of sonication and channel size on the desulfurization efficiency was investigated. It was shown that the sonicated contactor had higher desulfurization efficiency than the silent contactor in all channel diameters, and its performance intensification increased with the channel size. The enhancement ratio of the sonicated contactor rose from 5.81% to 16.82% by increasing the channel diameter from 0.79 mm to 1.78 mm. Furthermore, the multi-stage extraction has been performed and 97.57% sulfur removal was achieved.