Residue hydrotreating

Feedstocks for this very flexible process are usually vacuum distillates, deasphalted oils, residues (hydrotreated or not), as well as by-products from other processes such as extracts, paraffinic slack waxes, distillates from visbreaking and coking, residues from hydrocracking, converted in mixtures with the main feedstock. 

Feedstock 50/50 Arabian light and heavy crude VD VD hydrotreated Atm. residue hydrotreated... 

Two commercial residue hydrotreating catalysts, NiMo/Al203 and a C0M0/AI2O3, were used in this study. The properties of the catalysts are summarized in Table 1. Gas oil and Kuwait vacuum residue were used as feedstock for performance evaluation. Detailed analyses of these petroleum fractions are presented in Table 2. 

The residual hydrotreated shale oil was mixed with regular refinery cat cracker feed at a rate of 3%, with no detectable shifts in yields or other adverse consequences. Similarly, the gasoline range cut had no detectable effects on hydrocracker operations at 1.5% of feed. 

Residue Hydrotreating. A commercial Ni-Mo/y-AhOa hydrotreating catalyst was used to process a heavy petroleum fraction. The coke left on the catalyst was characterized by C CP/MAS-NMR technique, in order to determine the carbon types present in the coke, after times on stream ranging from 100... 

Residue Hydrotreating. - A Ni-Mo/y-AbOs coked catalyst was studied with XPS, to determine the location of the coke deposits . As coke accumulates on the catalyst surface up to 10%, the Mo concentration only slightly changes, and the Ni/Mo atomic ratio was constant at 0.3 in all the samples. On the other hand, the surface A1 concentration decreased sharply as the coke content increased. These data suggest that the coke was deposited preferentially on the alumina support rather than on the catalytically active components. 

Trickle bed reactors have grown rapidly in importance in recent years because of their application in hydrodesulfurization of naphtha, kerosene, gasoil, and heavier petroleum fractions hydrocracking of heavy gasoil and atmospheric residues hydrotreating of lube oils and hydrogenation processes. In trickle bed operation the flow rates are much lower than those in absorbers. To avoid too low effectiveness factors in the reaction, the catalyst size is much smaller than that of the packing used in absorbers, which also means that the overall void fraction is much smaller. 

The resulted catalyst are used in the front-end of reactors used in petroleum residue hydrotreating processes to remove the foulant metals (V and Ni).The catalyst posses high activity for promoting HDM reactions together with some activity for HDS reactions. 

Verstraete JJ, Le Lannic K, Guibard I. Modeling fixed-bed residue hydrotreating processes. Chem. Eng ScL 2007 62 5402-5408. 

With the first commercial residue hydrotreating plant being built in Japan in the late 70s, several units for direct residue HDS have been planned and constructed (Kuwait, for example). 

Residue hydrotreating in fixed-bed reactors is similar to heavy distillates hydrotreating, used as a feed preparation step for conversion processes (FCC or hydrocracking). The main application of the process is the removal of impurities such as sulfiir, nitrogen and metals. In addition to this, the process provides partial conversion of the residue feedstock of up to 35wt% of the feed. 

Euzen,J.P., (1991), Moving-bed process for residue hydrotreating . Revue de I lnstitut Frangais du P trole. Vol 46, N°4, July-August 1991. 

Callejas, M.A., Martinez, M.T., Blasco, T., Sastre, E. 2001a. Coke characterization in aged residue hydrotreating catalysts by solid-state C-NMR spectroscopy and temperature programmed oxidation. Appl. Catal. A Gen. 218 181-188. 

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