| 摘要 |
The invention relates to a process for preparing concentrated sulfuric acid by conducting a gas stream containing SO3 and H2SO4-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processes of this type is obtained by maintaining such temperature conditions in the tower that the recycle acid is withdrawn from the tower at a temperature T4 determined by the formula T4>140+6 alpha + beta +0.2(T1-Td) where alpha is the concentration of SO3+H2SO4 vapor in the inlet gas to the tower, beta the concentration of water vapor in the same inlet gas, T1 the temperature in DEG C. of the same inlet gas and Td 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.
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