VERFAHREN ZUM REGENERIEREN VON SCHWEFELSÄURE AUS SCHWEFELHALTIGEN STOFFEN

A conventional method for the regeneration of sulphuric acid from sulphur-containing residual materials comprises the following method steps: thermal cleavage of the residual material in a cleavage reactor by combustion of one or several energy sources with an oxidising agent in the form of oxygen to form process gas with a given sulphur dioxide content, generation of contact gas by mixing of the process gas with oxygen-containing gas, introduction of the contact gas into a contact kettle in a sulphuric acid contact plant and catalytic reaction of the sulphur dioxide contained in the contact gas to give sulphuric acid and/or oleum. According to the invention, an economical method, starting from the above, can be provided, permitting an increase in the turnover of sulphur dioxide of a contact plant, in particular permitting the design capacity of the contact system for an existing contact system for the production of sulphuric acid and/or oleum to be exceeded without any disadvantages, whereby at least a first partial stream of the contact gas is introduced in to a pre-contact vessel before introduction into the contact vessel, in which sulphur dioxide is oxidised to give an SO3-containing reaction gas and the SO3-containing reaction gas is introduced into an intermediate absorber, in which SO3 is absorbed and finally introduced into the contact vessel in the form of an SO2-depleted gas.