HETS
also known as height equivalent to a theoretical stage · HETP
HETS is the height equivalent to a theoretical stage: the vertical distance over which a column achieves the mass transfer that one perfectly mixed, perfectly settled stage would achieve. Column height for a target separation equals the theoretical stage count multiplied by HETS. For packed columns the equivalent term is HETP.
Why it matters in practice
HETS is empirical and system-specific — it changes with the chemistry, the flow rates and the column's internals. That is the core scale-up risk of columns: unlike a mixer-settler, whose stage efficiency can be measured directly, a column's performance per metre is only known with confidence after it has been tested at scale.
Where this appears on this site
Equipment referenced in this entry
Turbine Extraction Column
6 Specifications · extraction column
Packed Extraction Column
5 Specifications · extraction column
Related terms
Reference entry GL-HETS. Definitions on this page describe engineering practice in hydrometallurgical process design; they are not a substitute for test work on your own material.