Forced Circulation Evaporator
Forced Circulation Evaporator is used for concentration of high viscosity material and products with higher solids. Liquid to be concentrated is circulated through the tube at high pressure using a pump. This elevates the boiling point of the fluid, and boiling does not occur. Forced circulation also creates a degree of agitation. When the liquid passes through the tubes into vapor head, pressure suddenly drops, leading to the flashing of super-heated liquor. This is what brings about the evaporation effect.
An external mechanical action is used to pump certain portion of concentrate back into the feed where it enters the evaporator. High concentrate to feed ratio is achieved as re-circulation increases the heat transfer coefficient of the feed. Also, the high velocities generated with the mechanical force ensure high heat transfer due to turbulence. The high velocities and low residence time achieved in a small space (due to high heat transfer) help to eliminate probability of feed reacting with the vessel and causing scaling.
- Relative freedom from salting, scaling, and fouling.
- High rate of heat transfer.
- Heat exchange is optimized through flow velocity in tubes by the circulation pump
- Positive circulation
- Food Processing – Tomato paste manufacturing, fruits pulp concentration etc
- Effluent treatments
- Chemicals – Sodium sulphate crystallization etc