چكيده به لاتين
In the present study, the extractive desulfurization of model diesel fuel has been investigated using different deep eutectic solvents (DESs) in the micro-channels device. This study is categorized in three sections. In the first section, eight different DES were synthesized using polyethylene glycol 200 (PEG200) and propionic acid (Pr) as hydrogen bond donor (HBD) in combination with four different hydrogen bond acceptor (HBA) in a micro-channel. The sulfur removal, slug length, specific interfacial area, and volumetric mass transfer coefficient were investigated for different examined DESs. The remarkable sulfur removal of 62.16% and 75% was achieved using triethylamine/PEG200 with molar ratio of 1:3 (TEA/PEG200 [1:3]) and triethylamine/Pr with molar ratio of 1:3 (TEA/Pr [1:3]) in the residence time of 3 s, respectively. By considering initial sulfur concentration of 100 ppm, the highest sulfur removal in the micro-channel was 78.28% using TEA/Pr [1:3], which was achieved in the residence time of 25 s. In the second section of this study, the extractive desulfurization from the model diesel fuel was investigated in different micro-channels using triethylamine/propionic acid with the molar ratio of 1 to 3 (TEA/Pr [1:3]) as DES. In this regard, the effect of operating parameters (i.e., extraction time, temperature, and fuel to DES volume ratio) and micro-channel geometrical parameters (i.e., the diameter of the micro-channel, and length of the micro-channel) on the sulfur removal and volumetric mass transfer coefficient was investigated. In addition, the slug, droplet and different annular flow regimes were observed in the different micro-channels through two-phase flow visualization. Moreover, the effect of multiple extractive desulfurization cycles, reusability and regeneration of spent TEA/Pr [1:3] has been also investigated. It was found that the best geometry for the micro-channel is 0.6 mm in the diameter and 20 cm in length considering the sulfur removal and mass transfer coefficient. The achieved sulfur removal was 70.8%, 68.7%, and 44.4% from the model fuels containing dibenzothiophene (DBT), benzothiophene (BT), and thiophene (Th) in a very short residence time of 17 s by considering initial sulfur concentration of 300 ppm, respectively. The overall volumetric mass transfer coefficient in the micro-channel was 0.679 s-1 in the model fuel to DES volume ratio of 5. In the last section, design expert was employed for extractive desulfurization in the micro-channels in order to present an empirical model and optimize the process.
