Deep desulfurization of diesel oil: kinetic studies and process-improvement by the use of a two-phase reactor with pre-saturator

Abstract

Desulfurization of liquid fuels is usually obtained by heterogeneous catalyzed hydrodesulfurization (HDS). Improvement of this process is needed, particularly with respect to future low residual S-contents of about 10 ppm . Up to now HDS of diesel oil is performed in a trickle bed reactor equipped with an expensive H 2-recycle, although the H 2-supply is far beyond the amount chemically consumed, at least for deep HDS of an already hydrotreated feed. In addition, scale up of trickle bed reactors is in general problematic. In this work kinetic studies and above all a new HDS-concept using a two-phase reactor is presented. Thereby the oil is externally pre-saturated with H 2 and only the liquid phase is passed over the catalytic fixed bed. The H 2-recycle is then redundant, the intrinsic reaction rate can be utilized, and scale-up problems do not occur. In addition, this concept can also be used for HDS of oils with a higher content of sulfur and/or unsaturated hydrocarbons by installing a liquid recycle.