A study has been made of entrainment generation in a submerged coil evaporator and a vertical-tube natural circulation evaporator. Both evaporators generated about the same amount of entrainment at comparable boil-up rates. The decontamination efficiency of a submerged coil evaporator is correlated to the boil-up rate. The efficiency of a bubble-cap column, a Raschig ring packed tower, and a glass wool packed tower as de-entrainment devices was studied, the glass wool packed tower proving to be the most effective.