Falling film evaporator

Gentle evaporation for temperature-sensitive products

The cost-effective falling film evaporator is the most commonly used type of film evaporator due to its wide operating range.

Detail view of tubes inside a tube sheet falling film evaporator
Main benefits
  • High heat transfer coefficients
  • Short residence time on the heated tube surface
  • Low pressure drop
  • Suitable for operation under deep vacuum
  • High evaporation ratios
  • Low susceptibility for fouling
  • Suitable for GMP applications
  • Sizes from 0.3 to 4800 m2
  • Single pass or with recirculation
  • Process vapors and liquid flow co-currently or counter-currently
  • Multi-stage systems, sometimes in combination with wiped film evaporators
Main applications
  • Especially for low viscous products
  • Suited for products with low fouling tendency
  • Chemical industry
  • Petrochemical industry
  • Polymer industry

 

Process
Skid-mounted unit with a falling film evaporator as column reboiler
Skid-mounted unit with a falling film evaporator as column reboiler

Process

Our film evaporators treat your temperature-sensitive products in a gentle way: The use of vacuum and the short residence time along the heated surface are two essential parameters in preventing secondary reactions and preserving organoleptic properties.

Our falling film evaporator is specifically suited to process your products with a low viscosity and a low tendency for fouling. It consists of a tube bundle crowned by a proprietary liquid distribution device that ensures an efficient and uniform distribution of the liquid to all the tubes. Your product flows as a continuous film along the tube length, driven by gravity.

Usually the liquid and the vapors formed flow co-currently from the top to the bottom and are separated in a gas-liquid separator installed at the end of the tube bundle. This separator is not required in counter-current applications (for example, stripping) or when the falling film evaporator is used as the reboiler of a distillation column.

Distribution system

Distribution system

Our distribution is a two-stage system, featuring high accuracy and a wide operating range. The optimum sizing is achieved with our proprietary design tool.

In the first stage, process liquid enters the falling film evaporator through the inlet feed pipe and is directed to the top liquid distributor. The distributor then delivers the liquid to the tube sheet. It is itself equipped with many drip points to ensure the generation of an even and calm static liquid height outside the tubes.

Special features
Tube inserts of a falling film evaporator
Tube inserts of a falling film evaporator

Special features

  • Removable type for easy installation 
  • Guides plates in slits to generate a tangential liquid entry 
  • Slits at tube sheet level thus providing a self-draining possibility 
  • Well suited for processes with polymerization problems 
  • Flexible range of operation
  • Precision laser-cut manufacturing
       
Experience

Experience

  • Sulzer has over 60 years of experience in sizing and manufacturing falling film evaporators 
  • Over 600 evaporators installed worldwide
  • To ensure reliable equipment design, and to verify that the desired process performance meets your product specifications, we test your individual process in our pilot plant facilities. If you prefer, we can provide you with mobile test equipment on a rental basis to apply in tests at your own facilities.
Documents
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