A separation process is any process that can take a combination or mixture of different components and extract at least one component in a higher purity than in the original mixture. Distillation, evaporation, and crystallization are common separation processes in chemical engineering. Experts use chemical engineering to design a new separation process for each project they propose.
There are many ways to design a separation process. The distillation of alcohol for the production of liquor is done by boiling the original mixture of fermented fruit. Once vapors start to rise, engineers start to cool and condense those vapors which have a higher purity of alcohol. This distillation process is done under precise conditions because other contaminates are also separated during the distillation process.
Evaporation is used as a separation process usually when a solid product is covered with a fluid, like water. Clouds are created by evaporation when warm dry air collects water as it passes over bodies of water. This same process is used and creatively designed to act as a separation process. Chemical engineers calculate which warm gases will collect cooler fluids to invent new evaporation separation process. Often vacuums and pumps are used to control the flow of gases.
Crystallization is used in the pharmaceutical industry. In chemical engineering, separating the active ingredient from the other components in a batch requires adding hydrochloric acid for a limited time. The medicine gets absorbed in the acid, and by drying it under the right conditions, it causes crystallization. This forms small crystals with the active ingredient as a powdered medicine, which is then pressed into a pill shape for use.
Other common types of separation processes can be seen in waste removal. Most are used in water waste plants, like flotation. Chemical engineering is used to determine what will simply float to the top and how to skim it off, like trash in a river.
A liquid-liquid separation process has a purpose in water waste plants that is similar to oil floating on water. If fluids do not mix well they will form bubbles and layers. This can be increased for easy extraction with the use of selective heating. Heating a pool of waste water to boil with cause all of the organic components to rise to the surface. Chemical engineering uses heat and additives to create a distinct separation between water and wastes.