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What is Wiped Film Distillation?

Updated: Mar 11, 2019


Wiped film distillation is a thermal separation process for products that are sensitive to heat. The equipment used to achieve this process is known as a wiped film evaporator, and in the case of certain wiping systems, it can also be referred to as a thin film evaporator. The low evaporation temperature and short residence time causes little thermal stress on the distilled product and this results to a gentle distillation. The thin film distillation equipment is designed with the capabilities of handling challenging evaporating requirements when the materials in question are of low thermal conductivity, sensitive to heat, and highly viscous.


The technology of wiped film distillation introduces a mechanical agitated thin film of materials to a hot surface, which yields the separation of volatile compounds. The entire process is ideal for separating, concentrating, decolorizing, refining, and deodorizing, as well as offering wider product development opportunities in the pharmaceutical, polymers, chemical, and food industries. Some of the typical products that can be handled under this process include fatty amines, fatty acids, esters, tall oil, plasticizers, urea, fruit juices, and rocket fuel.


How Does the Process Work?


Generally, different wiped film vacuum distillation procedures are used for a partial separation of mixtures. What matters for all distillation processes is the difference in the boiling point of the two fractions that are being separated. For wiped film distillation, a decrease in the boiling temperature is achieved by lowering the operating pressure. The process is continuous, and it requires a short residence time.


This makes thermal separation a success, which could not be the case in other continuous or non-continuous conventional distillations methods that apply high temperatures with long residence times. Ideally, the wiped film distillation process takes place in the following order:

  • The feed product is introduced into the inlet via the distributor plate, passing through evenly spread out weirs all the way to the internal heated wall.

  • Rotating wipers spread the material into an even thin film. It also continues moving highly sticky materials towards the hot wall.

  • The vaporized material will then pass via an entrainment separator before condensing on the inner U bundle condenser.

  • The non-condensable escape through the vapor outlet and the distillate go through the distillate outlet.

  • Some liquid droplets that the entrainment separator will trap will flow out of the separator into a residue collector.

  • Finally, there are extruder blades attached to the rotor assembly that mechanically push the residue towards the outlet.

The wiping system is important in the best wiped film distillation, as it must generate a high turbulent film and a short residence time as mentioned earlier.



Benefits of Wiped Film Distillation Equipment


  • The short retention times eliminate product dilapidation

  • It has floating wipers that maintain the thin film

  • The best thin film distillation equipment improves unit efficiency

  • They offer reduced downtime, optimal running costs, low maintenance costs

  • They also come with energy saving features

Ideally, as seen above, the process of wiped film distillation is done through equipment that will enable the molecules to escape from the warm liquid into a surface in the condenser without degrading their value. At Hydrion Scientific Instrument LLC, we offer wiped distillation equipment among other products such as vacuum filtration units. We also offer professional advice on equipment selection. Contact us today for lab equipment orders.