Evaporator

The overall performance of evaporators depends on factors such as the heat transfer coefficient, tube/plate material properties, flow regime, and achieved vapor quality.

Advanced control techniques, such as online fouling detection, help maintain evaporator thermal performance over time.

Additionally, computational fluid dynamics (CFD) modeling and advancements in surface coating technologies continue to enhance heat and mass transfer capabilities, leading to more energy-efficient vapor generation.

Some air conditioners and refrigerators use compressed liquids with a low boiling point that vaporizes within the system to cool it, whilst emitting the thermal energy into its surroundings.

In the case of desalination of seawater or in Zero Liquid Discharge plants, the reverse purpose applies; evaporation removes the desirable drinking water from the undesired solute/product, salt.

Large ships usually carry evaporating plants to produce fresh water, reducing their reliance on shore-based supplies.

Diesel engine ships often utilize waste heat as an energy source for producing fresh water.

A brine-air ejector venturi pump is then used to create a vacuum inside the vessel, achieving partial evaporation.

For this reason, the evaporator is adjusted as seawater temperature changes and shuts down altogether when the ship is maneuvering.

The vapor is removed entirely (like in cooking), or it is stored for reuse (like in a refrigerator) or a product for isolation (essential oil).

Rotary evaporators use a vacuum pump to create a low pressure over a solvent while simultaneously rotating the liquid flask to increase surface area and decrease bubble size.

The rotary evaporator is best used for removing solvent from solutions containing the desired product that will not vaporize at the operating pressure to separate the volatile components of a mixture from non-volatile materials.

This evaporator is usually applied to highly viscous solutions, so it is frequently used in the chemical, sugar, food, and fermentation industries.

In many cases, the tubes of a rising film evaporator are usually between 3–10 metres (9.8–32.8 ft) in height with a diameter of between 25–50 millimetres (0.98–1.97 in).

Sizing this type of evaporator requires a precise evaluation of the actual level of the liquid inside the tubes and the flow rates of the vapor and film.

This type of plate evaporator is frequently applied in the dairy and fermentation industries since they have spatial flexibility.

A negative point of this type of evaporator is its limited ability to treat viscous or solid-containing products.

Fouling also occurs when hard deposits form on the surfaces of the heating mediums in the evaporators.