Ar Hansmeier

Desulfurization and denitrogenation of gasoline and diesel fuels by means of ionic liquids

Ionic liquids can extract mono- and poly-aromatic sulfur and nitrogen compounds from gasoline and diesel and they perform better than conventional solvents. The extraction capacity of several ionic liquids for these heterocyclic compounds is determined and compared to the extraction capacity for aromatic hydrocarbons. Furthermore, the experimental results obtained are evaluated in view of the results reported in literature. It is shown that the ionic liquids investigated in this work are able to extract sulfur as well as nitrogen-containing aromatics in preference to aromatic hydrocarbons. Moreover, the ionic liquids [3-mebupy]N(CN)2, [4-mebupy]N(CN)2 and [bmim]C(CN)3 are superior to sulfolane, which has been used as a benchmark and also outperform the ionic liquids reported in literature so far. Finally, it has been shown that nitrogen-containing hetero-aromatics are significantly better extracted than sulfur-containing hetero-aromatics.

Long term pilot plant experience on aromatics extraction with ionic liquids

Since 2004, we have been conducting pilot plant trials with various contactors and different ionic liquids for petrochemical model feeds as well as real refinery feeds. Our pilot plant contains a Rotating Disc Contactor with a height of 6 m and a diameter of 60 mm. Up to 100 kg of ionic liquid and 200 L of feed are applied in experiments. In this paper, the hydrodynamic and mass transfer performance of a rotating disc contactor has been characterized for toluene/n-heptane, a model FCC feed and a real LCCS refinery feed using 3-methyl-N-butyl-pyridinum dicyanamide ([3-mebupy]N(CN)2) as the ionic liquid. Experiments with the real LCCS feed demonstrated comparable extraction performance to the model FCC feed. Over the past 5 years, the same batches of the ionic liquid have been repeatedly regenerated by evaporation and reused. Our studies revealed that, although coloration occurs, the extraction performance of the ionic liquids has not changed even after several years of usage. After the real LCCS refinery feed experiments, validation with the toluene/n-heptane model feed confirmed unchanged extraction performance. Supplemental materials are available for this article. Go to the publishers online edition of Separation Science and Technology to view the free supplemental file.