Intensification of extractive desulfurization in micro-channels using triethylamine/propionic acid as deep eutectic solvent

In this study, the extractive desulfurization from the model fuel was investigated in different micro-channels using triethylamine/propionic acid with the molar ratio of 1 to 3 ([TEA:3Pr]) 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. Moreover, the effect multiple extractive desulfurization cycles, regeneration of spent [TEA:3Pr] 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. The slug and throat-annular flow regimes were observed in the different micro-channels through two-phase flow visualization. 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, respectively. The overall volumetric mass transfer coefficient in the micro-channel was 0.679 s-1 in the fuel to DES volume ratio of 5. It was also found that deep sulfur removal can be achieved using multiple-extraction cycles.

Automated summary

The extractive desulfurization from the model fuel was studied in different micro-channels using triethylamine/propionic acid as DES. The effects of various operating parameters and micro-channel geometrical parameters on sulfur removal and mass transfer were investigated. Multiple extractive desulfurization cycles and regeneration of the spent DES were also studied. The results showed that the sulfur removal efficiency was high, and deep sulfur removal could be achieved using multiple-extraction cycles.