Multiple Effect Evaporators
We offer both forced circulation Evaporators and Falling film Evaporators for the high TDS Effluent concentration and recovery of Valuable inorganic salts like Sodium Sulphate, Sodium Hydroxide and Sodium Chloride.
Forced Circulation Evaporators
Forced Circulation Evaporators are short tube evaporators and are ideally used when the boiling of feed liquid on the heating surface is to be avoided due to the salting and fouling characteristics of the liquid. Hence in these evaporators the flow velocity in the tubes is kept very high. In these evaporators the liquid is circulated at high velocities in the tubes of the heat exchanger while steam is provided in the chest. This liquid is partially evaporated when the pressure is reduced in the vapour-liquid separator to the corresponding boiling temperature. High volume, low head axial flow circulation pumps are used for recirculation of the crystal laden slurry in the evaporator and hence the operation of this evaporator is independent of the temperature difference.
Falling Film Evaporators
Falling Film Evaporators are designed to flow liquid and vapour parallel downwards. Liquid feed is preheated to boiling temperature. Preheated feed is distributed by specially designed distributor positioned above the top tube plate. An even thin film is formed in the heating tubes and flows downwards at boiling temperature while evaporation. The falling film is going with gravity. This results in a thinner, faster moving film and improved heat transfer coefficient.
Rising Film Evaporators is designed by using a vertical tube with steam condensing on its outside surface. Liquid on the inside of the tube is brought to a boil, the vapours generated forming a core in the centre of the tube. As the fluid moves up the tube, more vapour is formed resulting in a higher central core velocity that forces the remaining liquid to the tube wall. Higher vapour velocities in turn result in thinner and more rapidly moving liquid film.