METHOD AND DEVICE FOR ELECTROCHEMICAL CATALYST OXIDATION OF SULPHUR DIOXIDE

The electrochemical, catalytic oxidation of sulphur dioxide to sulphuric acid is carried out by bringing a gas mixture having a sulphur dioxide content of 0.01 to 50% by volume simultaneously into contact with oxygen and an electrolyte - water or a solution of sulphuric acid - over a catalyst which is activated carbon or activated carbon provided with metal complexes of organic compounds (porphyrins, anulenes, phthalocyanines, and the like) or products of their thermal decomposition, or activated carbon provided with platinum, palladium or rhodium in amounts of 0.1 to 1% by weight and has been made hydrophobic by means of hydrophobic polymer compounds (polytetrafluoroethylene, polyisobutylene, polyethylene, and the like) or by means of a mixture of a few of these compounds at a ratio of catalyst : hydrophobisizing agent of 25:1 to 1:4 at a reaction temperature of 10 to 80 DEG C. In the apparatus according to the invention, the hydrophobisized catalyst is applied as a porous catalytic layer to sheets made of a hydrophilic fibre base or a porous base, which leads to formation of a three dimensional matrix for holding back and draining the acid. These catalytic sheets are arranged such that gas ducts are formed between them whose constant volume is secured by means of spacing elements. The upper ends of the catalytic sheets are mounted in the distributing tank for the acid feed. The electrochemical, catalytic oxidation of sulphur dioxide to sulphuric acid with simultaneous participation of oxygen and water takes place in the porous layers of the hydrophobisized catalyst which forms a spacing layer between liquid phase and gas phase.