Principle of Forced Circulation Evaporator:
Forced Circulation Evaporator Uses mechanical pumps to circulate the liquid through the evaporator, enhancing the heat transfer rate and preventing fouling and scaling.
Construction:
Heat Exchanger: Typically, a shell and tube design where the liquid is heated.
Circulation Pump: Forces the liquid through the heat exchanger.
Evaporator Body: Where the liquid is flashed into vapor and liquid phases.
Separator: Separates the vapor from the concentrated liquid.
Condenser: Condenses the vapor back into liquid.
Working:
The liquid to be evaporated is pumped through the heat exchanger where it is heated.
The heated liquid enters the evaporator body where it flashes into vapor and liquid.
The vapor is separated and condensed, while the concentrated liquid is recirculated through the system.
This cycle continues until the desired concentration is achieved.
Uses:
Concentrating heat-sensitive and viscous solutions.
Used in the dairy, pharmaceutical, and chemical industries.
Merits:
High heat transfer coefficients due to forced circulation.
Reduces fouling and scaling in the heat exchanger.
Effective for viscous and heat-sensitive liquids.
Demerits:
High energy consumption due to the use of pumps.
Complex construction and operation.
High initial and maintenance costs.