Patent ID: 7449103

Claim:
A method of upgrading a pre-existing ebullated bed hydroprocessing system in order to reduce formation of coke and/or sediment, comprising: (a) operating a pre-existing ebullated bed hydroprocessing system comprising one or more ebullated bed reactors, each of which comprises a liquid hydrocarbon phase, a solid phase comprised of an expanded bed of a porous supported catalyst, a gaseous phase comprised of hydrogen gas, and catalyst free zones above and below the expanded bed of the porous supported catalyst; (b) mixing an oil-soluble catalyst precursor composition with a hydrocarbon oil diluent at a temperature below which a substantial portion of the catalyst precursor composition begins to decompose to form a diluted catalyst precursor mixture; (c) after forming the diluted catalyst precursor mixture and prior to heating the catalyst precursor composition to a temperature at which a substantial portion of the catalyst precursor composition decomposes, mixing the diluted catalyst precursor mixture with a heavy oil feedstock to form a conditioned feedstock comprised of a mixture of the heavy oil feedstock and diluted catalyst precursor mixture, wherein the conditioned feedstock contains from about 10 ppm to about 500 ppm catalyst metal by weight of the heavy oil feedstock prior to substantial decomposition of the catalyst precursor composition in order to dilute the catalyst precursor composition with the heavy oil feedstock prior to substantial decomposition of the catalyst precursor composition and in situ formation of a colloidal or molecular catalyst within the heavy oil feedstock upon further heating and decomposition of the catalyst precursor composition; (d) heating the catalyst precursor composition within the heavy oil feedstock in order to decompose the catalyst precursor composition and form a colloidal or molecular catalyst having a particle size less than 100 nm in situ within the heavy oil feedstock; (e) introducing the heavy oil feedstock from (c), optionally after (d), into at least one ebullated bed reactor of the pre-existing ebullated bed hydroprocessing system to form an upgraded ebullated bed hydroprocessing system comprising the one or more ebullated bed reactors and in which the colloidal or molecular catalyst is dispersed throughout the liquid hydrocarbon phase including what were previously catalyst free zones in the at least one ebullated bed reactor of the pre-existing ebullated bed hydroprocessing system; and (f) operating the upgraded ebullated bed hydroprocessing system to form a hydroprocessed material, the colloidal or molecular catalyst catalyzing beneficial hydroprocessing reactions throughout the liquid hydrocarbon phase, including what were previously catalyst free zones in the pre-existing ebullated bed hydroprocessing system, thereby reducing formation of coke or sediment in the upgraded ebullated bed hydroprocessing system compared to the pre-existing ebullated bed hydroprocessing system.