An overview of adsorptive desulfurization of liquid transportation fuels over various adsorbents including zeolites

Abstract

The conventional technique of hydrodesulfurization (HDS) faces challenges while removing refractory sulfur compounds from liquid fuels. Alternative techniques are under exploration. One of the alternative techniques is adsorptive desulfurization (ADS). In ADS, an adsorbent is used to remove sulfur through physical or chemical adsorption. Moreover, it is possible at ambient conditions. Recent developments in the area of ADS is the focus of the present review. Various adsorbents have been assessed for ADS of the model and real feedstocks. These include both activated carbons and zeolites. Their modification through incorporation of metal ions can improve the performance. Present paper reviews recent progress regarding the development of adsorbents. Improvement of selectivity and stability along with regeneration and reuse too, reviewed. Regeneration studies are helpful in knowing the reusability of adsorbents. Various methods of regeneration such as thermal, solvent and their combination have been addressed. Thus, present paper covers modification, testing, regeneration and reuse of adsorbents for ADS of liquid fuels. Equilibrium, kinetic and thermodynamic studies relevant to chosen topic also reviewed. Challenges do exist in testing adsorbents for ADS of commercial fuels. These challenges arise due to the competitive adsorption between sulfur compounds and aromatics. For commercialization of ADS, the development of adsorbent with cheaper metal ions and ideal regeneration methods are essential.