Dynamic catalytic adsorptive desulfurization of real diesel over ultra-stable and low-cost silica gel-supported TiO2

To develop dynamic ultra-deep catalytic adsorptive desulfurization (CADS) of real diesel using ultra-stable and low-cost silica gel-supported TiO2 is the aim of the work. A two-stage dynamic breakthrough model was built to describe the CADS process, varied with H/R ratio and O/S ratio. The desulfurization capacity reached 1.3 mg-S/g-A at the breakthrough concentration of 5 ppm-S. Various types of silica gel were screened as the substrate for TiO2, and the textural/acidic properties and CADS capacity were correlated in high relevancy. The effectiveness of diverse oxidants on CADS and the oxidation path were elucidated via combined experiment/simulation. Adsorption enthalpy derived from fitted isotherm data was calculated as 33.4 kJ/mol. The TiO2/silica gel-based sorbent demonstrated remarkable recyclability/stability in 10 cycles. An effective and economic route to eliminate the trace amount of stubborn sulfur compounds in low-sulfur diesel is provided, which can be potentially implemented as the final polishing step for ultra-clean diesel production. (c) 2018 American Institute of Chemical Engineers AIChE J, 64: 2146-2159, 2018