Ultra-deep desulfurization process of diesel fuel with adsorption treatment

Activated carbon with certain physical properties has capability for removal of sulfur compounds, especially the refractory sulfur species, e.g., 4,6-dimethyldibenzothiophene in diesel fuel. Also, the spent activated carbon of sulfur breakthrough can be regenerated by washing with a warm aromatic solvent. Based on these characteristics of activated carbon, a new flow scheme with high energy and capital efficiency for clean diesel fuel production was proposed. The use of this new process in refineries enables existing diesel HDS units to produce diesel fuel with a lower sulfur content without increasing the severity in HDS reaction or reducing the throughput. This process is applicable to existing diesel HDS units requiring modification to comply with the new, severer regulations on sulfur level. The technical and economic application of this new process to refineries with FCC or coker facilities is discussed.