To design a distillation unit or a similar chemical process, the number of theoretical trays or plates ( that is, hypothetical equilibrium stages ),, required in the process should be determined, taking into account a likely range of feedstock composition and the desired degree of separation of the components in the output fractions.
22.
The Harbor Hill Moraine, named for its prominence at Harbor Hill, Roslyn, New York, the highest point in Nassau County, resulted from a lingering equilibrium stage in the glacier's episodic retreat, creating a stationary melting front; the Long Island area became permanently free of glacial ice in the range of 13, 000 to 12, 000 YBP ( Years Before Present ).
23.
Distillation and absorption separation processes using packed beds for vapor and liquid contacting have an equivalent concept referred to as the "'plate height "'or the "'height equivalent to a theoretical plate ( HETP ) . " " " HETP "'arises from the same concept of equilibrium stages as does the theoretical plate and is numerically equal to the absorption bed length divided by the number of theoretical plates in the absorption bed ( and in practice is measured in this way ).
