ABSTRACT
To obtain satisfactory performance of ammonia stripping, proper design and operation of stripping facilities is required. To achieve an advanced performance, in addition to the requirements, an improved process control is needed. The differences in the performance of the stills, specifically in the one still operation mode, indicate that further improvement of the treatment is possible through some optimization of operational strategy. A scattergram analysis of the 1982 effluent data has showed that during that year only two serious upsets occurred in the treatment system, which otherwise consistently produced an effluent of well below 100 mg/L of residual ammonia. The DOFASCO coke-plant in Hamilton, Ontario, used the previously described conventional liming ammonia stripping system until 1978 when a modified pre-liming system was introduced. The coke-plant effluent is introduced to the upper part of ammonia still and flows down through several bubble-cap trays where it is brought into contact with the counter current flow of steam.
