FALLING FILM
EVAPORATOR

A Falling Film Evaporator comprises a vertical shell-and-tube heat exchanger (Calendria) with a liquid distributor unit and a vapour-liquid separator. Its ease of operation and time-efficiency makes it one of the most widely used evaporators.

The product is fed into the top distributor unit. The liquid from the distributor unit uniformly falls through the tubes forming a consistent layer across its walls.For distribution, stationery distributor and spray nozzles also can be used. The steam is injected through the inlet which heats the falling liquid and evaporates the liquid partially. The vapour and the liquid flows downward into the bottom of the calendria. The residual liquid accumulates at the bottom on the tube side, and the vapour travels through a duct into the attached vapour-liquid separator. The vapour is let out from the top of the separator, and the residual liquid, at the bottom, is fed back into the distributor unit with help of a pump, until the desired concentrationis arrived at.

For better results, normally, these evaporators are used in a series that createmultiple effect evaporation.

ADVANTAGE PLEIAD FALLING FILM EVAPORATORS

UNIQUE LIQUID DISTRIBUTOR DESIGN –

The efficiency of falling film evaporator entirely depends on designing an effective distributor unit that dispenses the liquid uniformly across the tubes, so that there is a continuous flow forming a consistent film along the tubes.Uneven distribution leads to fouling and greatly reduces the efficiency of the evaporator.

PLEIAD designs liquid distributors that dispense the liquid in an unvarying flow ensuring greater vapour efficiency and preventing fouling. Pleiad supplies geometrically structured stationary, as well as spray nozzle type distributor, based on the product to be handled.

COST & ENERGY EFFICIENT –

The vapour that is generated from the single effect evaporator (as in the figure above) has the same enthalpy (heat content) as that of the heat provided through the steam input due to less temperature difference in heating & boiling. Hence, multistage evaporation, with more no. of effects, is more energy efficient and effective.

Thus, in long-term the investment of a multiple effect evaporator system is amortized over the period by the energy saved in the process.

With an in-depth understanding of the thermodynamics, engineering and chemical behavior, PLEIAD designs customized evaporator solution that is best suited to your process and commercial needs.

KEY FEATURES

1. Efficient liquid distributor design
2. Consideration of wetting parameter
3. High heat transfer coefficients
4. Vapour liquid separator geometry and sizing (with limiting terminal velocity)
5. Pump sizing and selection as per the wetting requirement
6. Critical installation check
7. Automation as per process requirement
8. Additional glass window for manual checking
9. Clean, Robust & Easy to Operate

APPLICATIONS

These evaporators are ideal for non-viscous liquids that are temperature sensitive, which require lower residence time and when it is required to hold lower volumes of liquid.

  • Gelatin
  • Milk, juices
  • Herbal extracts, tea, coffee etc.
  • Lean salt solutions
  • Pulp and Paper industry