Both Evaporation and Distillation are processes, which involve the transformation of matter from the liquid stage to the gaseous state. Evaporation is a process of vaporization, whereas Distillation is the process, which is used to separate a liquid mixture from particular components and/or substances by using various boiling and condensation method.
Evaporation vs Distillation
The main difference between Evaporation and Distillation is that the temperature required to initiate both processes is different. For Distillation, the liquid is required to reach the boiling point, whereas the process of Evaporation starts before the liquid reaches the boiling temperature. However, there are indeed certain factors, which may be the same for both of these processes, but by considering all the cases, they are different, enormously.
Evaporation is a type of vaporization. This process takes place when heat is applied to a matter in its liquid state, which leads to the transformation of the latter into the gaseous state. One thing to note over here is that the gas, which is surrounding the matter while this process is going on, must not be saturated.
Distillation is a process that is an ancient, traditional, and effective one for desalination. The process starts when the liquid reaches its boiling point. Fundamentally speaking, Distillation can help in partial or complete separation, which increases the saturation or concentration percentage of the component, which is present in the mixture.
Comparison Table Between Evaporation and Distillation
| Parameters of Comparison | Evaporation | Distillation |
| Initiation of the Process | Evaporation starts even before the liquid reaches its boiling point. | Distillation starts when the liquid reaches the boiling point. |
| Place of Occurrence | Evaporation occurs at the surface area. | Distillation does not occur at the surface area. |
| Nature of Technique | Evaporation is not a technique for separation. | Distillation is completely a separation technique. |
| Time for the Process | Evaporation is a slow and gradual process. | Distillation is a swift and rapid process. |
| Formation of Bubbles | In Evaporation, no liquid bubbles are formed at the boiling point. | In Distillation, liquid bubbles are formed at the boiling point. |
What is Evaporation?
Evaporation is a process, which involves the transfer of energy from one liquid molecule to another one and, while doing the latter to have transmission of heat energy. When a liquid molecule, which is near to the surface, absorbs enough heat energy and is successful in overcoming the vapor pressure, the latter escapes and enters into the surrounding air in its gaseous state.
Practically, only a small fraction of liquid molecules have heat energy, which is enough to escape from the vaporized state. The process of evaporation continues until the time an equilibrium is met, where the amount of liquid evaporation is equal to the amount of condensed liquid. Evaporation is comparatively a very slow and gradual process. The process starts even before the liquid reaches its boiling point. Moreover, evaporation takes place at the surface itself.
Evaporation is a very essential and crucial part of the water cycle and is one of the best examples of the latter process. Water evaporation takes place when the surface of the liquid is exposed, which allows the molecules to be released and form water vapor, which later on forms clouds. This complete natural evaporation process starts with the heat, which is emitted from the sun.
What is Distillation?
Distillation is a process, which is used as a separation technique. Distillation can also have few types, like classical distillation and dry distillation. Classical distillation is the process, which is used to separate components or particles from the liquid base or mixture by using methods like boiling and condensation.
However, dry distillation is the process where the solid components or materials are heated to produce their gaseous state, which afterward can be condensed into liquid or solids. Distillation is not a chemical process or reaction but a physical separation process. Distillation is an ancient, traditional, yet very effective technique of desalination.
The process of distillation initiates when the liquid mixture or base reaches its boiling point. It is a very quick and rapid method as compared to the other processes, which are used for separation. Liquid bubbles are formed in this method.
Distillation has many applications, both commercially as well as industrially. The distillation of fermented products is used to produce distilled beverages, which have a high content of alcohol or separates other fermented products, which have high commercial value. Moreover, for industrial use, cryogenic distillation is used. The latter is used to break the air into its components, specifically oxygen, nitrogen, argon.
Main Differences Between Evaporation and Distillation
- Evaporation is a slow process, whereas Distillation is a quick process.
- Evaporation occurs at the surface only, whereas Distillation happens inside as well.
- Evaporation starts even before the liquid reaches the boiling point, whereas Distillation starts only when the liquid reaches the boiling point.
- Evaporation is not a technique for separation, whereas Distillation is completely a process for separation.
- In Evaporation, no liquid bubbles are formed at the boiling point, whereas in the process of distillation, liquid bubbles are formed when the liquid reaches the boiling point.
Conclusion
Though both the processes of evaporation and distillation have a lot of similarities and have many common factors, still, by analyzing all the cases, both of them have a lot of differences. Amongst the many parameters of differences between the two methods, the few most notable ones are the temperature at which each of the processes initiates or the time each of the processes takes.
In the process of distillation, external heat energy is required to be transmitted to the liquid molecule to start the whole process. This helps the molecules get converted into the gaseous state. However, in the case of evaporation, external heat energy is not required. In the process of evaporation, the molecules get energized when they collide with each other, during the process. That same energy is used to release the liquid molecules, convert and get released into the vapor or the gaseous state.
References
- https://www.degruyter.com/document/doi/10.1515/9783110654806-002/html
- https://www.sciencedirect.com/science/article/pii/S0022169408001789