Vacuum evaporation
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Vacuum evaporation is the process of causing the pressure in a liquid-filled container to be reduced below the vapor pressure of the liquid, causing the liquid to evaporate at a lower temperature than normal. Although the process can be applied to any type of liquid at any vapor pressure, it is generally used to describe the boiling of water by lowering the container's internal pressure below standard atmospheric pressure and causing the water to boil at room temperature.
The vacuum evaporation treatment process consists of reducing the interior pressure of the evaporation chamber below atmospheric pressure. This reduces the boiling point of the liquid to be evaporated, thereby reducing or eliminating the need for heat in both the boiling and condensation processes. There are other advantages, such as the ability to distill liquids with high boiling points and avoiding decomposition of substances that are heat sensitive.[1]
Application
Food
When the process is applied to
This process was invented by Henri Nestlé in 1866, of Nestlé Chocolate fame,[citation needed] although the Shakers were already using a vacuum pan before that (see condensed milk).
This process is used industrially to make such food products as evaporated milk for milk chocolate and tomato paste for ketchup.
In the sugar industry vacuum evaporation is used in the crystallization of sucrose solutions. Traditionally this process was performed in batch mode, but nowadays continuous vacuum pans are available.[2]
Wastewater treatment
Vacuum evaporators are used in a wide range of industrial sectors to treat industrial wastewater.[3] It represents a clean, safe and very versatile technology with low management costs, which in most cases serves as a zero-discharge treatment system.
Thin film deposition
Vacuum evaporation is also a form of
See also
- Freeze drying
- List of waste-water treatment technologies
- Vacuum deposition
References
- PMID 17321675.
- ^ BMA Gruppe. Article on continuous vacuum pans. Retrieved 21 September 2011.
- ^ Condorchem Envitech. "Vacuum evaporators" as a technology for industrial water-based liquid waste minimization and treatment. Retrieved 27 January 2009.