Microwave-assisted extraction for refining of petroleum wax distillate feedstock

Abstract

The removal of multiple-ring aromatics from the petroleum fractions in general and lubricating oil feedstocks particularly have been conventionally done either by solvent extraction or hydrotreatment processes. Both techniques however, they could attain reasonable rates in removing aromatic and sulfur compounds, they suffered from certain drawbacks. Specifically, the elevated operating costs of both routes due to the long operational time and its dependent massive energy consumption are a big issue. In an attempt to overcome such restrictions, the current research study introduces a novel approach in the removal of condensed aromatic compounds by using microwave supported solvent-extraction process. The process of microwave-assisted extraction (MAE) was performed in parallel to the conventional extraction process to precisely compare the features of the obtained products out of each of process. Time of exposing the extraction system to the microwave radiation, the intensity of radiation power and solvent to feed ratio are the main investigated parameters during the microwave-assisted extraction. Promising results have been detected at the end of the presented research study. Extreme reduction in the operational time by applying microwave technology, 15 min, compared to the conventional extraction (90 min) was successfully attained. This reduction could be associated with extra-low energy consumption in the case of microwave-assisted extraction (MAE) in comparison to the conventional route. Specifically, the energy consumption was reduced by 99.75% than that in the case of conventional solvent extraction. In addition, an enhancement in the percentage of aromatics removal, 12.5%, was achieved in the microwave-assisted extraction compared to the conventional route. Furthermore, the sulfur removal has come up to nearly 60% in the case of MAE while it was about 50% for the conventional solvent extraction process.