Removing trace amount of refractory sulfur compounds from diesel under mild conditions has been a great challenge in refinery. Recently, Xiao’s lab from South China University of Technology proposed an effective and economic desulfurization approach (catalytic adsorptive desulfurization, CADS) for ultra-clean fuel production under mild conditions.
A coupling oxidation-adsorption process was developed for selective desulfurization. Plausibly, such CADS approach shows superior desulfurization uptake at low sulfur concentration range, fast adsorption kinetics, excellent regenrability, operation at mild conditions, and facile and low-cost adsorbent synthesis. CADS may provide a promising path for ultra-deep desulfurization to achieve ultra-clean diesel. For more details, read X. Ren et al. / Fuel 174(2016) 118-125.
Xiaoling Ren, Guang Miao, Zhiyong Xiao, Feiyan Ye, Zhong Li, Haihui Wang, Jing Xiao,
School of Chemistry and Chemical Engineering and Key Laboratory of Enhanced Heat Transfer and Energy Conservation, South China University of Technology, Guangzhou 510640, China.
This study investigates catalytic adsorptive desulfurization (CADS) of model diesel fuel using TiO2/SBA-15 under mild conditions. The TiO2/SBA-15 was prepared by a facile incipient wetness impregnation method and characterized by N2 adsorption and X-ray diffraction. The CADS referred to ADS performance were evaluated in a batch reactor.
High desulfurization uptake of 12.7 mg/g was achieved at low sulfur concentration of 15 ppmw-S by TiO2/SBA-15 under CADS, which was two-magnitude higher than that under ADS without the in-situ catalytic oxidation of dibenzothiophene. Kinetic results suggested that the CADS equilibrium over TiO2/SBA-15 was reached fast in 0.5 h. In the CADS–TiO2/SBA-15 system, the TiO2 loading, cumene hydroperoxide/dibenzothiophene ratio and CADS temperature were optimized to be 10 wt%, 2, and 35 °C, respectively.
Furthermore, desulfurization tests in 5 consecutive CADS-regeneration cycles suggested that the bi-functional TiO2/SBA-15 can be regenerated by acetonitrile washing followed with oxidative air treatment. The CADS–TiO2/SBA-15 mechanism went through the oxidation of DBT to oxidized DBTO2 over TiO2/SBA-15 by cumene hydroperoxide, which was followed by the adsorption of the oxidized DBTO2 over TiO2/SBA-15.
The superior desulfurization uptake at low sulfur concentration range, fast adsorption kinetics, excellent regenerability, operation at mild conditions, and facile and low-cost adsorbent synthesis make the CADS–TiO2/SBA-15 system an effective and economic desulfurization approach for ultra-clean fuel production.Go To Fuel