Fast Electron Migration for Efficient Sodium Desulfurization by Producing Activated Sodium Metal Microspheres with Large Reaction Interfaces

Abstract

Achieving a highly efficient desulfurization of heavy feed oils using sodium metal remains challenging due to its restricted reaction interface. Herein, the membrane emulsification technology was adopted to produce monodisperse active sodium metal (aNa) microspheres with considerably enhanced reaction interfaces for efficient desulfurization without requiring a catalyst. By regulating the parameters, the molten sodium into the model oil using a membrane device, optimized aNa microspheres with a particle size of 27.71 μm and a large specific surface area of 2.17 × 105 m2·m−3, which was 50−100 times larger than that of microspheres prepared via mechanical agition, were obtained. On the basis of the rich reaction interfaces, the efficient sodium desulfurization would proceed via Coulomb-like explosion initiated by aNa to form solvated electrons and cleavage of the C–S bond at one end to generate C+ ions, which trigger the final cleavage of the C–S bond in benzothiophene under the continued attack of the fast C+ ions electron cloud, together with the generation of styrene and sodium sulfide. With the assistance of hydrogenation, a fast and efficient benzothiophene desulfurization was achieved with a desulfurization efficiency of >90% within 15 min under the optimized reaction conditions, i.e., reaction temperature, pressure, and Na/S ratio. This work provides a fast and efficient sulfur removal technology to replace the conventional catalytic hydrodesulfurization.

Keywords: Membrane emulsification, Sodium desulfurization, aNa microspheres, Benzothiophene, C+ ions electron, Enhanced reaction interfaces