New Approach for Catalytic Production of Ultralow-Sulfur Diesel Fuels Using Binary Composed Catalysts Consisting of Cobalt Nanoparticles

The global trend is orientated toward the production of diesel fuels composed of as low as 50 ppm (0.05 g/L) or even less sulfur compounds. As a result, the current study is orientated toward the generation of a diesel fuel with reduced sulfur content via the catalytic route. This research work introduces novel approaches in the catalytic desulfurization field through providing new perspectives. A special attention has been paid throughout this research toward the usage of advanced catalytic compositions in the sulfur removal application. Unlike the commonly known catalysts for the desulfurization processes that are basically metal oxides of different structures, catalysts with mixed structures are introduced in this study. Two novel cobalt catalysts based on metallic (zero-valent) and hydroxide structures were utilized to catalytically remove sulfur from the feedstock of the diesel fuel. The two catalysts were synthesized by the electroless deposition technique using two different reducers. The effect of these reducing agents on both the structure of the catalysts and their subsequent performance in the designated process was investigated. The diesel fuel manufactured in this study contains low content of sulfur; in addition to this, ultralow catalytic operational conditions had been other advances that have been concluded at the end of this work. Particularly, a temperature of 100 °C, liquid hour space velocity equals 1, and hydrogen-to-feed ratio of 100:1 were applied during the currently presented sulfur removal process. At these nonsevere conditions, approximately 90% of the sulfur compounds in original feedstock (10 000 ppm equivalent to 10 g/L) were eliminated at the generated diesel fraction in this research study. This sulfur removal rate was then elevated to reach 99.5% through an adsorption step using the spent catalyst, which had been acquired at the optimum conditions of the catalytic sulfur compounds’ removal process. Thus, the ultimate diesel fuel containing 50 ppm sulfur compounds was obtained by the presented treatment processes.