Process for producing low sulfur coke

Claim 1

In an integrated coking and gasification process for the production of a low sulfur coke comprising the steps of: reacting a carbonaceous material containing sulfur contaminants, said carbonaceous material having a Conradson carbon content of at least 5 weight percent in a coking zone containing a bed of fluidized solids maintained at a temperature ranging from about 850° to about 1250° F. to form coke containing sulfur contaminants, said coke depositing on said fluidized solids; introducing a portion of said solids with the coke deposition thereon into a heating zone operated at a temperature greater than said coking zone temperature to heat said portion of solids; recycling a first portion of heated solids from said heating zone to said coking zone and introducing a second portion of said heated solids to a fluid bed gasification zone maintained at a temperature of at least 1600° F., and passing a stream of solids from said gasification zone to said heating zone, the improvement which comprises: controlling the rate of circulation of said solids between each of said zones such as to maintain the thickness of a shell of deposited coke, subjected to treatment within the gasification zone in a single cycle, ranging at the time of exit from the gasification zone to a thickness not greater than 10 microns, while introducing steam into the lower portion of said fluidized bed gasification zone to produce a hydrogen-containing gas and introducing an oxygen-containing gas into the upper portion of said fluid bed gasification zone to convert at least a portion of said hydrogen to steam and thereby produce at least a portion of the heat requirements of said process and recovering a partially desulfurized coke.