FIELD: chemical engineering. SUBSTANCE: invention relates to mineral acid concentration technology, especially to concentration of sulfuric acid. Process is effected by bringing initial sulfuric acid stream into countercurrent contact with hot medium in packed evaporator receiving sulfuric acid in its upper part to form emission gas and concentrated sulfuric acid. Initial sulfuric acid stream is fed at 150 to 270 C and emission gas is condensed either in vertical glass pipes of air-cooled drop-down thin-layer condenser or in packed tower-type concentrator, wherein gas comes into countercurrent contact with sulfuric acid recycle stream and then is returned into condensate cycle proceeding in the upper part of packed evaporator. Concentration of produced acid reaches 98.8%. EFFECT: increased concentration of sulfuric acid product. 8 cl, 2 dwg
