Process for the preparation of sulfuric acid

Abstract

The invention relates to a process for preparing concentrated sulfuric acid by conducting a gas stream containing SO.sub.3 and H.sub.2 SO.sub.4 -vapor in a sulfuric acid tower in countercurrent to liquid sulfuric acid formed through a concentrating zone containing filler bodies trickled with sulfuric acid and an absorption zone where sulfuric acid vapor is absorbed in recycled sulfuric acid on filler bodies trickled therewith. A very substantial reduction in the amount of acid mist formed in conventional processes of this type is obtained by maintaining such temperature conditions in the tower that the recycle acid is withdrawn from the tower at a temperature T.sub.4 determined by the formula T.sub.4 >140+6.alpha.+.beta.+0.2(T.sub.1 -T.sub.d) where .alpha. is the concentration of SO.sub.3 +H.sub.2 SO.sub.4 vapor in the inlet gas to the tower, .beta. the concentration of water vapor in the same inlet gas, T.sub.1 the temperature in .degree. C. of the same inlet gas and T.sub.d the dew point of the sulfuric acid vapor in the same inlet gas. The filters to catch acid mist may be smaller and they will only cause a very small pressure drop. The dimensions of the tower may be diminished to produce the same amount of concentrated sulfuric acid.

Dependencies are inferred from the claim text.