Rejuvenation of Residue Hydroconversion Catalysts by H-donor Solvents

Abstract

The spent hydroprocessing catalyst from conversion of bitumen was extracted with hydrotreated gas oil, tetralin and tetralin-pyrene as solvents at 400°C and 10 MPa hydrogen pressure in order to remove coke and rejuvennate catalyst activity. The reactive extraction of solvents partially removed the coke on catalyst with the order of effectiveness: gas oil \ tetralin \ tetralin-pyrene. Tetralin showed higher ability than the gas oil for the coke removal by donating hydrogen in situ to hydrogenate the coke. Binary tetralin/pyrene solvent mixture gave synergism for removing coke on the catalyst due to the ability of pyrene to shuttle hydrogen to form more active H-donors, hydropyrenes. HDS activity of the spent catalyst was enhanced after the coke removal.

Use of Hydrogen Donors for Partial Upgrading of Heavy Petroleum

“…Alcohols, hydrazine, cyclic olefins, and hydroaromatics have been employed as hydrogen donors for the transfer hydrogenation of various functional groups. Table shows the most common chemical species of different types of hydrogen donors that have been used so far. ,, …”

“…Table 1 shows the most common chemical species of different types of hydrogen donors that have been used so far. 39,58,59 Some hydrogen donors or hydrogen transfer solvents are polycyclic compounds free of carbonyl groups, type naphthenearomatic or naphthenic, which are dehydrogenated. They transfer hydrogen atoms to heavy hydrocarbon oil, reducing its viscosity and increasing its API gravity, and they minimize the polymerization reactions of the heavy molecules via a free radical mechanism (prevent coke formation).…”

Enhancing the selectivity of the hydrogenation of naphthalene to tetralin by high temperature water

“…27 1,2,3,4-Tetrahydronaphthalene (tetralin) is a very useful high boiling point solvent which has been widely used in paint, coatings, inks, pharmaceuticals, paper, hydrogen donors and in other fields. [28][29][30] Tetralin can be synthesized in a complicated Bergman cyclization or simply through the hydrogenation of naphthalene in the presence of noble metals or transition metals. [31][32][33][34][35] The reaction catalyzed by noble metals (e.g.…”