Process for removing sulphur from a gas

Claim 1

In a fluid catalyst cracking process including the steps of (a) cracking a sulfur-containing hydrocarbon stream in contact with a fluidized bed of a particulate cracking catalyst in a cracking zone at cracking conditions including a temperature in the range from 800° F to 1300° F, whereby sulfur-containing coke is deposited on said catalyst, and removing the hydrocarbon stream from said cracking zone; (b) passing coke-containing catalyst from said cracking zone and an oxygen-containing gas into a cracking catalyst regeneration zone, burning off said sulfur-containing coke therein at a temperature in the range from 1000° F to 1500° F to form a flue gas containing sulfur oxides, and removing said flue gas from said catalyst regeneration zone; and (c) returning the resulting coke-depleted catalyst from said catalyst regeneration zone to contact with said hydrocarbon stream in said cracking zone; the method for decreasing the amount of sulfur oxides in said flue gas which comprises the steps of: 1. reacting sulfur oxides in said flue gas with reactive alumina contained in a particulate solid other than said catalyst, the particulate solid being physically admixed with said particulate catalyst, in said regeneration zone to form at least one solid compound including sulfur atoms and aluminum atoms in said particulate solid, and removing said flue gas from said regeneration zone; and 2. forming hydrogen sulfide from said solid compound and said hydrocarbon stream by contacting said particulate solid with said hydrocarbon stream in said cracking zone in physical admixture with said particulate cracking catalyst, and removing hydrogen sulfide from said cracking zone in said hydrocarbon stream.