Heavy aromatic solvents for catalyst reactivation
AssigneeSaudi Arabian Oil Company
InventorsOmer Refa Koseoglu, Robert Peter Hodgkins
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Abstract
Compositions and methods for restoring catalytic activity by dissolving soft coke with a solvent, one method including detecting soft coke deposition on a catalyst composition; preparing an aromatic bottoms composition with a Hildebrand solubility parameter of at least about 20 SI to remove the soft coke from the catalyst composition; and washing the catalyst composition with the aromatic bottoms composition until at least a portion of the soft coke deposition is removed.
Claims21
A method for restoring catalytic activity by dissolving soft coke with a solvent, the method comprising the steps of:
- detecting soft coke deposition on a catalyst composition;
- preparing an aromatic bottoms composition comprising low-quality bottoms product from a xylene rerun column of an aromatics recovery complex with bridged di-aromatic molecules and at least 50 wt. % C9+ aromatic hydrocarbons, wherein C6-8 aromatics have been separated out, and with a Hildebrand solubility parameter of 20 (SI) or greater to remove the soft coke from the catalyst composition;
- and
- washing the catalyst composition with the aromatic bottoms composition until at least a portion of the soft coke deposition is removed in order to recover hydocracking and hydrotreating catalyst activity.
A method for hydrocracking a hydrocarbon feedstock to reduce soft coke deposition, the method comprising the steps of:
- hydrocracking the hydrocarbon feedstock in a reactor at a reaction temperature in a range of from about 300° C. to about 500° C., at a reaction pressure in the range of from about 50 bars to about 200 bars, at a hydrogen feed rate up to about 2500 standard liters per liter of hydrocarbon feed (SLt/Lt), and a hydrocarbon feed rate in the range of from about 0.25 h−1 to about 3.0 h−1 liquid hourly space velocity;
- detecting a pressure drop over a catalyst bed in the reactor;
- reducing the temperature of the reactor;
- reducing flow of the hydrocarbon feedstock;
- providing to the catalyst bed an aromatic bottoms composition comprising low-quality bottoms product from a xylene rerun column of an aromatics recovery complex with bridged di-aromatic molecules and at least 50 wt. % C9+ aromatic hydrocarbons, wherein C6-8 aromatics have been separated out, and with a Hildebrand solubility parameter of 20 (SI) or greater to remove soft coke from a catalyst composition in the catalyst bed;
- and
- re-starting hydrocracking of the hydrocarbon feedstock.
Dependencies are inferred from the claim text.