Fixed bed adsorption of benzothiophene over zeolites with faujasite structure

Abstract

This work addresses the adsorption of benzothiophene (BT), as a model heterocyclic and aromatic sulphur compound present in road fuels, over agglomerated zeolites with faujasite structure. Several adsorbents based on zeolites with FAU structure have been prepared with different Si/Al molar ratios and exchange cations and then agglomerated. The influence of the zeolite basicity has been studied, both in equilibrium and dynamic liquid phase adsorption experiments. Basicity of the adsorbent increased as the Si/Al molar ratio and the electronegativity of the exchange cation decreased. In equilibrium experiments, the affinity towards the adsorbent increased as the Si/Al molar ratio decreased, showing the highest affinity for exchanged low silica X zeolites with medium basicity (A-KLSX-02). Dynamic experiments showed that the less zeolite basicity, the higher fractional bed utilization and adsorption capacity at breakthrough time. Besides, zeolites with high basicity did not reach the equilibrium capacity due to the low diffusivity of BT into the micropores. Thermogravimetric analyses of the spent adsorbents showed a stronger BT adsorption onto the more basic zeolites. As main conclusion, adsorbents with medium basicity could present the best performance in fuel desulphurization due to their high affinity with sulphur compounds, although diffusion problems should be taken into account.

Ultra-deep adsorptive removal of thiophenic sulfur compounds from FCC gasoline over the specific active sites of CeHY zeolite

“…The hydroxyls of Si(OH)Al groups are not recovered fully. At this time, most possibility is because the confinement effect of pore channels can hinder the desorption of BTP, which is similar with that of on the NaY and literatures reported [70][71][72] .…”

Review of Adsorptive Desulfurization of Liquid Fuels and Regeneration Attempts

“…The adsorbents (without metal) show a maximum sulfur adsorption capacity in the range of 4.72–23.5 mg/g over an initial concentration range of 250–700 ppm. The metal-doped adsorbents show an adsorption capacity in the range of 0.39–86.4 mg/g sulfur at an initial concentration of 50–2000 ppm. ,− …”

Adsorption of Dibenzothiophene by Vermiculite in Hydrophobic Form, Impregnated with Copper Ions and in Natural Form

“…To meet more stringent regulations and to make ultra-low sulfur fuels for fuel cell applications (Song and Ma 2003), ultra-deep desulfurization of liquid hydrocarbon fuels has become an increasingly important issue in environment and energy studies worldwide. Currently, the major desulfurization technology is hydrodesulfurization (Sotelo et al 2007). However, the presence of organic sulfur compounds in fossil fuels is increasingly restricted.…”