Forced Circulation Evaporators
Forced circulation evaporators are used for concentration of liquids containing high suspended solids and which have high scaling or crystal forming tendency at increased concentration. In forced circulation evaporator the feed enters the calandria from bottom and is pumped upwards through the tubes with the help of axial or centrifugal pump. The velocity of the feed in the tube is maintained such that there is no scale formation on the tubes. As the liquid rises in the tubes it boils and this liquid when passed to the vapour liquid separator flashes off the vapours. The concentrated liquid flows down to the recirculation pump and the vapours are either passed to the next effect calandria or to the condenser.