Document Type : Review Article
The production of clean liquid fuels is critical to maintaining a healthy life and environment around the world. To meet the new sulfur standard requirements, sulfur compounds must be effectively and completely removed from fuel oil. Therefore, researchers' attention turned to research into different techniques to remove sulfur from kerosene. This review focused on discussing a variety of catalysis approaches and emerging technologies for ultra-deep desulfurization of refinery streams for ultralow sulfur, such as hydrodesulfurization, catalytic-oxidative desulfurization, and adsorption desulfurization to form clean liquid fuels. This review discusses the most important industrial parameters that influence sulfur removal processes and has focused primarily on the main role of the catalyst and its type in impacting the efficiency of the process. Also, it will discuss the concepts of nano-catalysts, their preparation methods, and the most common forms, were described such as graphene, carbon nano-tubes (CNTs), metal-organic frames (MOVs), and zeolites. A comparison between the nano-catalyst and the conventional catalyst was also discussed to show the great effect of the nano-catalyst in improving the removal processes, which will lead to the development of innovative, efficient desulfurization methods that produce zero-sulfur fuels. In addition, understanding the most important challenges in nano-catalysts.