Difference Between Evaporation and Distillation

What are Evaporation and Distillation?

Evaporation

Evaporation is described as a type of vaporization method that occurs on the liquid's surface as it changes into the gas phase. The gas that is surrounded must not be saturated with the evaporating substance. The liquid molecules transfer energy to each other when they collide, depending on how they collide with. When a molecule available near the surface absorbs enough energy to overcome the vapor pressure, it will escape and enter into the surrounding air in the form of gas. When evaporation occurred, the energy which has removed from the vaporized liquid will reduce the liquid temperature, resulting in evaporative cooling.

On average, only a fraction of the liquid molecules has enough heat energy to escape from the vaporized liquid. This evaporation will continue until an equilibrium is reached when the liquid evaporation becomes equal to its condensation. Throughout the enclosed environment, a liquid will be evaporated until the surrounding air is saturated.

Evaporation is a necessary component of the water cycle. Solar energy (sun) drives evaporation of water from water resources such as lakes, oceans, soil moisture, and other sources of water. In hydrology, it is said that evaporation and transpiration (which involves evaporation within the plant stomata) are collectively termed as evapotranspiration. Water evaporation takes place when the surface of the liquid gets exposed by allowing the molecules to escape and form water vapor. Then, this vapor can rise and then form clouds. The liquid will turn into vapor having sufficient energy.


Applications of Evaporation

  • Industrial applications include most coating and printing processes. These include drying a variety of materials such as paper, lumber, cloth, and other chemicals, and recovering salts from solutions.

  • The evaporation used to concentrate or dry samples is a common preparatory step for most of the laboratory analyses like chromatography and spectroscopy. These systems include centrifugal evaporators and rotary evaporators.

  • If clothes are hanging on the laundry line, even though the ambient temperature falls below the water boiling point, water evaporates. This is accelerated by factors including heat from the sun, low humidity, and wind. Hot air is blown through the clothes in a clothes dryer, allowing water to evaporate rapidly.

  • A traditional Indian porous clay container called Matki/Matka is used to cool and store water and other liquids.

  • A traditional Spanish porous clay container called Botijo, designed to cool the contained water by the evaporation process.

  • Evaporative coolers can cool a building significantly by merely blowing dry air over a filter saturated with water.


Distillation

The process of separating the substances or components from a liquid mixture by using selective condensation and boiling refers to distillation. Essentially, distillation can result in a partial separation or a complete separation (approximately pure components), that increases the concentration of the selected component present in the mixture. In the other case, the method exploits differences in the relative volatility of the mixture's components. Considering the industrial chemistry, distillation is a unit operation practically of universal importance. Still, it is a process of physical separation, not a chemical reaction.


Applications of Distillation

  • The distillation of fermented products forms distilled beverages with a strong alcohol content or separates certain other fermentation products having commercial value.

  • Distillation is a traditional and effective method of desalination.

  • Oil stabilization is a kind of partial distillation in the petroleum industry, that lowers the vapor pressure of crude oil, making it safe, thereby for transport and storage, and reducing the atmospheric emissions of volatile hydrocarbons. In oil refineries midstream operations, fractional distillation is a primary operational class for converting crude oil into fuels and also chemical feedstocks.

  • Cryogenic distillation tends to separate air into its components, notably oxygen, argon, and nitrogen for industrial use.

  • Huge amounts of crude liquid products of chemical synthesis n the chemical industry are processed to separate them from the impurities, unreacted starting materials, or other products.

To discuss briefly, there is much difference between evaporation and distillation. A few of them are tabulated below.

Difference Between Evaporation and Distillation

Evaporation

Distillation

Evaporation is a method of changing a liquid into a gas by applying heat to the liquid for the molecules at the surface to change easily into a gas

Distillation is a process of acquiring gas or vapour from liquids. This is accomplished by boiling the liquid to obtain gas and condensing the obtained gas then to relevant liquid form for different purposes.

Evaporation is a gradual and slow process

Distillation is rapid and quick

It occurs at the surface

It doesn’t occur at the surface

It is not a separation technique

This is entirely a separation technique

There is no formation of liquid bubbles at the boiling point

It forms liquid bubbles at the boiling point

Liquid vapourisation occurs below the boiling point

Liquid vapourisation occurs at the boiling point


From the above-tabulated difference between evaporation and distillation, it can conclude that the primary difference between them lies at the boiling point. Evaporation occurs below the liquid boiling point, whereas distillation occurs right at the boiling point. Both processes depend on certain factors that may be the same, but considering all the cases, they are vastly different.

FAQ (Frequently Asked Questions)

1. Explain Distillation vs. Evaporation?

To brief on Distillation vs. Evaporation considering some special factors, we can say as below.

Features Differences

The evaporation process happens only at the liquid surface, whereas the distillation process doesn’t only happen at the surface of liquids.

Boiling Point Differences

In the evaporation process, the liquid vaporizes below its boiling point. But, on the contrary of the distillation process, the liquid vaporizes at its boiling point.

Duration of the Process Differences

The evaporation process is gradual and slow; besides, the distillation process is rapid or quick.

2. What is the Key Difference Between Distillation and Evaporation?

Some of the key differences between Distillation and Evaporation are given below.

  • In the distillation process, when the liquid reaches the boiling point, it forms bubbles. However, in the evaporation process, the bubbles do not form any bubbles because the liquid doesn’t reach the boiling point.

  • The distillation process is used for purification and separation of a liquid. However, evaporation isn’t so necessary.

  • In the distillation process, heat energy is required to be supplied to the liquid molecules. So that the liquid molecules will go into the vapor state. However, considering the evaporation, there is no need to supply external heat energy. The molecules instead get energized when they collide with each other during the process. The same energy is then used to release the molecules into the vapor state.