Evaporation deals with the concentration of a non-volatile solute from a solution by the removal of required amount of volatile solvent. Usually, the solvent is water. By vaporizing a part of the solvent, useful product i.e., the concentrated solution or thick liquor is produced and the vapours are discarded. Long tube evaporators are usually used for the concentration of foamy liquids. The set-up consists of stainless-steel tubes surrounded by a stainless-steel jacket and fitted with accumulator. Dilute solution is feed to tubes. Steam from a steam generator is supplied to shell to concentrate the dilute feed solution to a desired level. The jacket is fitted with a steam trap and the condensate is collected at the end of trap. The vapours of volatile solvent are condensed in a shell & tube type condenser and the balance non-volatile solute is collected in the accumulator.