Stripping columns are used to remove unwanted materials from process streams. The air stripping column shown below is used to remove ammonia from water and wastewater feedstreams. This section describes various types of air stripping columns as well as steam strippers.
A membrane is a thin barrier that permits the transport of certain species across it from one fluid to another. Membranes can be classified by the operating driving force for transport.
Ion exchange is based on sorption, the transfer of solutes from fluid to solid particles. Undesired anions or cations from a liquid are exchanged for ions of the same charge within a resin.
Humidifiers are used to increase the relative humidity of air. The most common humidification methods use either steam or fog.
Liquid-liquid extraction has only become popular as a separations technique in the past thirty years. In this time, liquid-liquid extractors have become the separation equipment of choice for selected processes.
Evaporators are used to separate materials based on differences in their boiling temperatures.
Drying is an operation in which moisture is removed thermally from a liquid/solid mixture. Dryers vary in application and function.
Distillation columns are one of the most often used types of separation equipment in industry.
Commercially, dehumidifiers are used to condition air for comfort and to protect areas from damage due to high humidity.
Crystallizers are used in industry to achieve liquid-solid separation. They are an important piece of chemical processing equipment because they are capable of generating high purity products with a relatively low energy input.