Process and device for carrying off free and combined ammonia from aqueous solutions containing both components

摘要

1. Process for stripping free and combined ammonia from aqueous solutions containing these two components, in which the combined ammonia is liberated by treatment with caustic soda and the free ammonia is stripped from the solution with steam and/or exhaust vapours and in which the process is carried out in columns fitted with suitable internals, characterized by the use of the following process features : a) The treatment of the ammoniacal feed solution is carried out in a single column consisting of three sections, of which the first (top) section and the second section below it are connected by a plate which is permeable to gas and liquid while the second and third sections are separated from each other by an impermeable plate : b) the ammoniacal feed solution is introduced at the head of the column into the first section of the same and after passing through the first section is divided into two component streams of which one component steam flows directly into the second section below while the other component stream is fed directly into the third section of the column via a by-pass line, in which the stripping vapour is introduced into the third and second sections of the column and the caustic soda is also fed into the second section, and c) the vapours rising in the third section of the column are introduced via a by-pass line into the second or the first sections of the same, while the regenerated solution leaving the third section of the column is transferred for re-use and the solution leaving the second section is rejected from the process after appropriate waste water treatment.