Do you want to know how to separate oil and water? Would you like to know how the separation process is carried out at an industrial level? In the following publication we are going to see the different machinery used in the industry and also how you can separate oil from water and salt at home in a simple way using some utensils and techniques .
Methods for separating water and oil
Among the methods that we can use to separate oil and water, we have centrifugation, decantation, evaporation and distillation. On the other hand, when the oil is in an emulsified state in the water, the application of additives and the heating and cooling processes help to separate the water from the oil.
Settling by gravity
Decanting by gravity is the easiest method of all to replicate at home, it simply requires patience and a suitable container. It is really easy to separate the oil from the water at home using a narrow container such as a measuring cylinder or a glass and a syringe to extract the oil present on the surface.
The decantation consists of allowing the mixture of water and oil to separate by the action that the force of gravity exerts on two bodies of different densities that makes the lighter fluid float above the heavier one. The density of olive oil at room temperature is 916 grams per liter, compared to 1,000 grams per liter of water, for which, being lighter, oil tends to stay above water over time.
In the case of olive oil, the decantation tanks allow the olive oil to be separated from the vegetation water that has managed to pass after the centrifugation process. These tanks, conical in shape at the bottom, have a tap at the bottom that allows the water to be extracted first and then to continue with the extraction of the oil.
Decantation by centrifugation
The decantation by centrifugation is one of the separation methods faster and more efficient. Centrifugal decanters allow the oil to be quickly separated from the water. In addition to water, they allow the oil to be separated from other solid remains and impurities. This kind of machinery is widely used at an industrial level in the production of vegetable oils such as olive oil. The centrifugal machines allow extracting the oil and the water from the vegetation from the oily must in the first place, separating a large part of the liquids from the solid vegetable residues and later they allow the water to be separated from the oil with a high degree of purity.
Evaporation or Distillation
Water evaporates at a lower temperature than oil. Due to this, when heating the mixture we can separate the water from the oil by distillation. However, this method is not very adequate because it is necessary to mobilize a significant amount of energy. In addition, the water vapor needs to break the film of oil on top of it to escape the mixture and causes explosions that can cause splashes and burns. This is due to the significant increase in volume that water undergoes when passing from a liquid to a gaseous state, multiplying the volume occupied by more than 1,600 times at a pressure of 1 atmosphere.
For its part, if in addition to the oil we want to preserve the water after separation, distillation is the most appropriate process.
Although it is a difficult process to replicate at home, since you will probably need to buy typical laboratory utensils ( distilling flask, condenser and receiving flask).
Separation of oil, water and salt
When in addition to oil and water we have salt, we must take into account that salt does not dissolve in oil. Therefore, in the first place we separated the oil from the water and the salt by means of decantation. For its part, to separate the water from the salt, we will proceed to use the Evaporation or Distillation method to later go on to separate the oil from the water and the salt to extract the olive oil, we can use the previous methods. In case the oil and salt are mixed, filtration would be the process to use to separate the salt from the oil.
What happens if water and oil are emulsified?
When water and oil are emulsified, they form a homogeneous mixture and the separation is somewhat more complex. During the emulsion, the oil particles are located dispersed in the water, making it necessary to break this dispersion in order to separate the mixture.
To break the emulsion, the following methods or techniques are used:
Addition of additives to the mix: Certain additives help to break the emulsion, for example, talc is used in certain cases to help improve extraction and increase the fat yield obtained during the extraction process after crushing the olives.
Another common additive is salt, the higher the concentration of salt in the water, the weaker the emulsion. Although chemical factors influence, on a physical level, this is due to the fact that salt water has a higher density than fresh water.
Centrifugation: The centrifugation process allows replicating the effect of gravity on a larger scale, the industrial machines used in the olive oil production are capable of applying relative centrifugal forces of the order of 3,000 to 4,000 times the force of gravity.
Temperature variation: In the case of stable emulsions, cooling and heating processes help the emulsion to break and the oil and water to separate.
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Warning
We have translated the information on our website from Spanish to English. Please note that some words may have had their meaning altered during translation.