Hydro-treating of Asphaltenes in Supercritical Toluene with MgO-Supported Fe, Ni, NiMo, and CoMo Catalysts

• Published in: Energy & fuels 2009-07, Vol.23 (7), p.3645-3651
• Main Authors: Xu, Chunbao (Charles), Su, Huasu, Ghosh, Mainak
• Format: Article
• Language: English
• Subjects: Applied sciences; Crude oil, natural gas and petroleum products; Energy; Exact sciences and technology; Fossil Fuels; Fuels; Processing of crude oil and oils from shales and tar sands. Processes. Equipment. Refinery and treatment units
• ISSN: 0887-0624; 1520-5029
• DOI: 10.1021/ef900126v

For the first time, the AVTB-derived asphaltenes (containing very high concentrations of sulfur (7.70 wt % S) and nitrogen (1.08 wt % N)) were hydrotreated over novel MgO-supported Fe, Ni, NiMo, and CoMo catalysts in supercritical toluene at 380 °C under hydrogen of 5 MPa (cold pressure) in a batch reactor. The supercritical toluene alone without any catalyst was found to be effective for conversion of the highly aromatic asphaltenes (AS) to less aromatic maltenes (MA) through a thermal cracking mechanism. All the MgO-supported catalysts proved to be effective for hydro-conversion of AS to MA in supercritical toluene. The activities of these catalysts for AS conversion showed the order of sequence of Fe/MgO < Ni/MgO < CoMo/MgO < NiMo/MgO. Among all the MgO-supported catalysts tested, NiMo/MgO was found to be the most active one for promoting the removal of sulfur and AS. The sulfur/nitrogen/AS removal efficiencies for the NiMo/MgO catalyst increased with the treatment time, and the efficiencies at 120 min of treatment attained as high as 43%, 30%, and 70%, respectively. The MgO-supported catalysts showed excellent performance for preventing and retarding the formation of highly condensed aromatics or coke in the hydro-treatment of AS in supercritical toluene. With the presence of NiMo/MgO catalyst, hydro-treating AS in the supercritical toluene for a reaction time up to 120 min produced a strikingly low yield (