Semi-dry flue gas desulphurisation process, preferably for fossil fuel power stations

摘要

To desulphurise flue gases, for example downstream of fossil fuel power stations, the flue gas, after passage through an electrostatic precipitator, is brought into contact with pulverulent lime in a reaction section, which lime is then separated from the flue gas again by a filter. Prior to the lime, a liquid is sprayed into the reaction section, which liquid contains mono- and/or polybasic carboxylic acids or salts thereof and/or inorganic acids or salts thereof and which is made up in a preparation vessel. The reaction products separated from the gas stream by the filter, essentially CaSO4 and CaSO3, are passed into an oxidation vessel in which the reaction to form gypsum is carried out, which is separated off from the suspension leaving the oxidation vessel. The remaining liquid is returned to the preparation vessel.