Molecular mechanism and experimental study of fuel oil extractive desulfurization technology based on ionic liquid

Abstract

In recent years, the sulfur-containing substances produced by fossil fuel combustion have caused overwhelming pollution to the ecological environment, and fuel desulfurization research is imperative. In this paper, 16 ionic liquids (ILs), which are environmentally friendly, easily degradable and have good prospects for industrial application, were selected by combining four cations and four anions for fuel desulfurization research. The desulfurization mechanism of ILs was first investigated by molecular mechanism studies, in which quantum chemical simulations were used for preliminary screening based on the selectivity coefficient of infinite dilution activity coefficient. And the experimental study of extraction desulfurization was carried out with dibenzothiophene (DBT) and n-heptane as model oils. The above mechanism study and experiments examined the effects of temperature, initial fuel oil concentration and ILs to fuel oil feed ratio on the extraction efficiency, and the results showed that both [C2COOCH3ImC6H13][N(CN)2] and [C2COOCH3ImC6H13][NTF2] ILs have more prominent extraction properties. Among them, [C2COOCH3ImC6H13][NTF2] exhibits high desulfurization efficiency for a wide range of sulfur concentration in fuel oils at room temperature due to the advantages of simple preparation method and easier industrialization of the [C2COOCH3ImC6H13][NTF2]. The above experimental results are fully consistent with the molecular simulation predictions, indicating that the theoretical study and experimental method proposed in this paper are simple and feasible.