In this scenario the survivalist is stranded on a remote island and clean drinking water is hard to come by. With minimal supplies including: some cotton cloth, a plywood board, a bed pan, a snorkel, a neck tie, 4 nails, and a knife the survivalist creates a simple distillation system to access clean drinking water.
Distillation is a process of separating the component substances from a liquid mixture by selective evaporation and condensation. In this example, the survivalist uses the bedpan to heat the water creating steam. He used the plywood board, the snorkel, and the neck tie capture the steam and cool it into clean drinking water.
The survivalist obviously needed to separate the clean water from the salt present in the seawater. By boiling the water, and condensing the steam created in the boiling process he separates clean water from the seawater mixture. Most types of industrial distillation systems operate in a very similar manner.
Take crude oil for instance:
- Raw crude is brought to a near boil by a preheater (bed pan).
- It is then introduced into a distillation column (Snorkel) under vacuum. The lower pressure in the column allows the crude to boil at a lower temperature. When it is introduced in the column, the lighter elements in the crude flash into vapor (steam) and rise to the top of the column, while the heaver elements fall to the bottom (Salt).
- The vapor (steam) that rises to the top is cooled back into a liquid form (water) in a condenser (wet neck tie).
- Once back in its liquid form it is drawn off as product (clean drinking water).
Industrial process systems and they unit ops that they utilize can be found all around us. You just need to take the time to make the connection between simplistic everyday processes and really understand what is going on. A good example is detailed in the article “How making coffee is like Industrial absorption”