Unit operations are basic steps in chemical engineering. It is a process that involves the chemical or physical transformation of a substance. Such processes include crystallization, separation, filtration, and evaporation, to name a few. The final goal is to come up with a product from raw material. The process may involve multiple unit operations before achieving the final product.
Examples of Unit Processing In Chemical Engineering
Take, for example, the manufacture of sugar. It starts with the crushing of the sugarcane, after which the manufacturer extracts the sugar. It then goes through a process of thickening the sugar with syrup. Other processes include water evaporation, sugar crystallization, filtering, and drying, screening then packing.
You will find the same processes in the pharmaceutical industry. The manufacturing of drugs goes through a series of processes. Such include granulation, milling, tablet pressing, and coating.
Unit operations use different equipment, such as compressors, pumps, and centrifuges.
Other examples of unit processing include:-
Distillation is the process of purifying liquids. You may also separate the different components if you achieve the right boiling temperature. There are many types of distillation, including: simple distillation, steam distillation, fractional distillation, and vacuum distillation.
Absorption involves transforming gas into a liquid, using physical or chemical processes.
Evaporation where liquids transform into a gaseous state. It requires the availability of water in order to occur.
Drying is the elimination of water or moisture. You will find its use in Pharmaceuticals, food, timber, and plastic Industries, to name a few. The most basic process involves the use of direct heat or dryers to evaporate the solvents. Some processes use vacuum dryers resulting in a reduction in atmospheric pressure around the product.
Understanding the Difference between Unit Processing and Unit Operations
You may find the words unit processing, and unit operations used interchangeably. Yet there is a difference between the two. Unit processing involves chemical changes before coming up with the final product. In some instances, there may be some physical changes as well. Such processes include oxidation, hydrogenation, and nitration. Unit operations involve physical changes that may result from the physical separation of different components during that process.