Denitrogenation of middle distillates using adsorbent materials towards ULSD production: A review

A review of the state of art in the denitrogenation process of middle distillates using adsorbent materials is discussed. More stringent environmental laws enforce refiners to produce cleaner fuels from heavy feeds. Sulfur compounds reduce fuel quality and release pollutants to the atmosphere by which its elimination is mandatory. Typical hydrodesulfurization (HDS) catalytic processes in refineries are limited to meet the required specifications for Ultra Low Sulfur Diesel (ULSD) and new processes and materials need to be developed. Removal of nitrogen compounds (N-compounds) from real feedstocks improves sulfur elimination because irreversible adsorption of N-compounds on acidic sites in HDS catalysts may be avoided. Research and development during the last decade is reviewed in this work, including results obtained with different types of N-compounds, adsorptive systems and adsorbents commercially available.