Sulfur removal from molecular-sieve catalyst
AssigneeUop LLC
InventorsLeonid Galperin, Robert S. Haizmann
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Abstract
A sulfur-sensitive catalyst which has been deactivated by accumulating sulfur on the catalyst is desulfurized by contact with ammonia at high temperature. The technique is particularly effective for reforming catalysts containing a large-pore zeolite which are selective for dehydrocyclization of paraffins. The desulfurization may be combined with regeneration for coke removal from the catalyst.
Claims7
A process for regenerating and removing associated sulfur from a sulfur-contaminated sulfur-sensitive reforming catalyst which contains nonacidic L-zeolite, an alkali-metal component and a platinum component consisting essentially of the steps of:
- (a) treating the contaminated catalyst at treatment conditions including a temperature of between about 250.degree. and 800.degree. C. with a gaseous mixture which comprises one or both of ammonia and a nitrogen compound which decomposes to form ammonia at conditions used to treat the catalyst to provide ammonia in a concentration in the gaseous mixture of between 1 and 100 mol % for a sufficient time to remove at least 50% of the associated sulfur and obtain a desulfurized catalyst;
- (b) contacting the desulfurized catalyst with an oxygen-containing gas at carbon-burn conditions;
- (c) redistributing the platinum on the reduced-coke catalyst at oxychlorination conditions with a chlorine- and oxygen-containing gas;
- (d) cooling the oxychlorinated catalyst with one or more cooling gases in series;
- and,
- (e) reducing the platinum with a hydrogen-containing gas to obtain a regenerated, desulfurized catalyst.
Dependencies are inferred from the claim text.