| 摘要 |
The present invention provides a process for concentrating sulphuric acids with concentrations of 90% to 98% H2SO4 and temperatures of 160<o>C to 270<o>C into sulphuric acid with concentrations of 96% to 98.8% H2SO4 by contacting the acid countercurrently in a packed tower with hot air or with hot process gas containing up to 6% SO3 and up to 30% H2O and with inlet temperatures to the tower of 350<o>C to 600<o>C. The H2O and H2SO4 evaporated in the tower is contained in a stream of offgas from which the H2SO4 thereafter is removed by controlled condensation. The invention relates, in particular, to concentrating the product acid from wet gas sulphuric acid plants in which condensation of H2SO4 takes place in the presence of excess H2O in the process gas in air cooled, vertical glass tubes.
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