Patent ID: 6893622

Claim:
In an improved process for the continuous preparation of oleum of a concentration of 10 to 45% by weight of SO 3 and/or sulphuric acid of a concentration of 94 to 100% by weight of H 2 SO 4 by combusting sulphur with atmospheric oxygen according to the principle of superstoichiometric combustion in a combustion chamber, cooling the resultant sulphur-dioxide-containing gases to 350° C. to 500° C., catalytically converting the resulting cooled gases to give sulphur-trioxide-containing gases in the presence of a vanadium-containing catalyst using single or double contact catalysis, absorbing the sulphur-trioxide-containing gases after cooling, optionally removing liquids from the gases after absorption and energy recovery, the improvement comprising injecting the sulphur as liquid sulphur into the hot combustion gas stream perpendicular to the main direction of flow in the form of a fan using one or more bimodal fan-type nozzles operating in pulsed operation, wherein injecting alternates between pressure injection and two-component injection.