Recent Insights in Transition Metal Sulfide Hydrodesulfurization Catalysts for the Production of Ultra Low Sulfur Diesel: A Short Review

Abstract

The literature from the past few years dealing with hydrodesulfurization catalysts to deeply remove the sulfur-containing compounds in fuels is reviewed in this communication. We focus on the typical transition metal sulfides (TMS) Ni/Co-promoted Mo, W-based bi- and tri-metallic catalysts for selective removal of sulfur from typical refractory compounds. This review is separated into three very specific topics of the catalysts to produce ultra-low sulfur diesel. The first issue is the supported catalysts; the second, the self-supported or unsupported catalysts and finally, a brief discussion about the theoretical studies. We also inspect some details about the effect of support, the use of organic and inorganic additives and aspects related to the preparation of unsupported catalysts. We discuss some hot topics and details of the unsupported catalyst preparation that could influence the sulfur removal capacity of specific systems. Parameters such as surface acidity, dispersion, morphological changes of the active phases, and the promotion effect are the common factors discussed in the vast majority of present-day research. We conclude from this review that hydrodesulfurization performance of TMS catalysts supported or unsupported may be improved by using new methodologies, both experimental and theoretical, to fulfill the societal needs of ultra-low sulfur fuels, which more stringent future regulations will require.

Materials for CO2, SOx, and NOx Emission Reduction

“…But SO x is obtained due to contamination of the fuel itself, and, accordingly, these impurities in some cases can (and should) be removed before burning; for this, hydrodesulfurization (HDS) processes at petroleum refineries are used. The permissible amount of sulfur compounds in diesel, gasoline, and kerosene is subject to stringent international standards [47,48].…”

The Role of Hydrogen in the Ecological Benefits of Ultra Low Sulphur Diesel Production and Use: An LCA Benchmark

“…Heavier oils tend to contain more impurities and thus extra refining resources are needed. Examples are deposits of northern Alberta (S content > 2%) and Mexican Altamira heavy crude oil (S content up to 6%) [13,14].…”

Clean Syn-Fuels via Hydrogenation Processes: Acidity–Activity Relationship in O-Xylene Hydrotreating

“…Due to increased environmental concern, the European Union has introduced the "zero-sulphur" legislation, which limits the sulphur content in gasoline and diesel less than 10 mg/kg [1], thus requiring the development of modern process technologies and the improvement of the actual hydrotreating catalysts for "very real" clean-fuels manufacturing [2,3]. Transition metal sulfide catalysts, usually consisting in molybdenum (Mo) supported on high surface area carriers and promoted by cobalt (Co) or nickel (Ni), are widely used in crude oils hydrotreatment [4][5][6][7][8][9]. The catalytic synergism of these systems relies on the formation of Co(or Ni)MoS phases, where the active sites are placed on both the metal and sulfur edges, and BRIM sites [10][11][12].…”