In a process for hydrocracking heavy polynuclear carbonaceous feedstocks to produce lighter hydrocarbon fuels by contacting said heavy feedstocks with hydrogen in the presence of molten zinc chloride catalyst in a hydrocracking zone, thereafter separating at least a major portion of said lighter hydrocarbon fuels from the spent molten zinc chloride and thereafter regenerating the spent molten zinc chloride by incinerating the spent molten zinc chloride by combustion of carbon and sulfur compounds in said spent molten zinc chloride in an incineration zone, the improvemnt comprising:
- (a) contacting said heavy feedstocks and said hydrogen in the presence of said molten zinc chloride in said hydrocracking zone at reaction conditions effective to convert a major portion of said heavy feedstocks to lighter hydrocarbon fuels;
- (b) contacting said spent molten zinc chloride with oxygen in a liquid phase gasification zone at a temperature and pressure sufficient to vaporize from about 25 to about 75 weight percent of said spent zinc chloride, said oxygen being introduced in an amount sufficient to remove from about 60 to about 90 weight percent of the carbon contained in said spent molten zinc chloride and produce a fuel gas;
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- (c) incinerating the remaining molten zinc chloride by combustion of the carbon and sulfur compounds in said remaining molten zinc chloride in an incineration zone to vaporize said remaining zinc chloride.