مسعود كرم زاده

In this research, the experimental investigation of oxidative-extractive desulfurization process of diesel fuel with an initial sulfur content of 1690 ppm has been carried out by using ultrasound assisted microfluidic systems. The experiments are divided into two sections; the first section explores the influence of operating parameters on the extractive desulfurization process in the microfluidic system in sonicated and silent conditions. The second section eva‎luates the oxidative-extractive desulfurization process in the microfluidic system and the geometrical parameters of the process. The initial investigation focused on the influence of residence time and solvent to fuel ratio in a batch system on the extractive desulfurization process efficiency. The conventional batch process achieved the highest desulfurization value of approximately 41 % with a retention time of 100 min and a solvent to fuel ratio of 1:1. After determining the optimal solvent to fuel ratio, the study examined the impact of different solvents, namely, methanol, acetonitrile, and dimethylformamide. The findings revealed that dimethylformamide had the highest sulfur removal efficiency. Furthermore, the results indicated that raising the volume flow rate from 2.86-10.5 mL/min increased the extractive desulfurization efficiency by 5-18% in sonicated mode compared to silent mode. The eva‎luation of energy consumption demonstrated that the incorporation of the sonication feature resulted in a rise in sulfur removal from 59 % to 70.3 %. However, the total sulfur removal per unit of electrical energy consumed also increased from 0.01 J/mg to 433 J/mg. The conclusion was that, despite the higher sulfur removal achieved with sonication mode, the electrical energy consumption for obtaining clean fuel energy drastically increased. Moreover, the oxidative desulfurization efficiency at optimal ratio (O/S=5) and (A/S=38) reduced the total sulfur content of diesel fuel from 1690ppm to 1274ppm, reaching 503 ppm after one stage of extraction in optimal conditions and 31 ppm after four stages of extraction. The desulfurization efficiency rose from 42.94 % to 70.25% by reducing the channel diameter from 1.78 mm to 0.79 mm. This is because decreasing the channel diameter reduces the slug size, which enhances the interfacial area between phases and shortens the diffusion path, leading to a higher desulfurization rate. The sonicated contactor’s enhancement ratio increased from 5.81% to 16.82% by enlarging the channel diameter from 0.79 mm to 1.78 mm. The findings indicated that while reducing the channel diameter improved the desulfurization efficiency, but this change could have negative effect on the process intensification of ultrasound-assisted microfluidic contactor, and the desulfurization efficiency was more positively influenced by ultrasound waves in the microfluidic system with a larger diameter.

سامانه هاي ريزسيالش , گوگردزدايي , اكسيداسيوني-استخراجي , سوخت ديزل

Microfluidic contactor , Desulfurization , Oxidative- Extractive , Diesel Fuel

Masoud Karamzadeh

Salman Movahedirad