Abstract: A device for treating gaseous effluents from a catalytic cracking unit comprises at least one first stage for regenerating a catalyst used in a catalytic cracking process wherein the gaseous effluents issuing from a cracking catalyst regenerator are treated in a heat recovery unit (CR) including a treating chamber having an entrained bed. The absorbent introduced in this chamber has a "fine" grain size ranging between 0.1 and 100 .mu.m and can be regenerated in the device downstream from heat recovery unit (CR).

Abstract: For generating heat, with reduced emission of sulphur and nitrogen oxides, a fuel containing sulphur oxides and nitrogen is effected, the combustion burned and particles of a fresh absorbent are fed into a turbulent zone (9) upstream of an adiabatic desulphurisation zone (8); and the mixture produced is passed into a heat recovery zone (16). Part of the absorbent is recycled to the desulphurisation zone, and the flow rate of fresh absorbent and recycled absorbent is adjusted so that the temperature of that zone is from 750.degree. to 1000.degree. C.