A process for regenerating, and reactivating, coked noble metal catalysts, especially platinum-containing polymetallic catalysts in a system which includes separate, interconnected primary and secondary regeneration gas circuits in which gas is circulated from one circuit to the other, (i) a primary regeneration gas circuit which contain a preheat gas furnace, a reactor which contains said catalyst from which said coke can be burned by contact with hot gas from said preheat gas furnace, and a steam boiler through which said hot gas can be passed and cooled, and the cool gas injected, or returned to said secondary circuit; and (ii) the secondary circuit is one which contains a regeneration gas scrubber, a gas drier (optional) and fines solids filter. The circuit also includes regeneration gas means, i.e. a compressor, for circulating the gas in said circuits. A gas, constituted in major part of flue gas, is passed through the preheat gas furnace, preheated, then passed into the coked catalyst-containing reactor wherein the coke is combusted by contact of a combustible mixture of the gas with the catalyst, the gas heated thereby, then cooled by passage through the steam boiler, and the cooled gas then injected into the secondary circuit. The hot flue gas, or gas within the secondary circuit, is conditioned for use as a purge gas within the primary circuit. It is countercurrently contacted with cooling water in a regeneration gas scrubber to condense out the combustion water and water desorbed from the catalyst, as well as extract the hydrogen chloride stripped from the catalyst.