Height equivalent per theoretical plate HETP

The properties of a fractionating column which are important for isotope separation are (1) the throughput or boil-up rate which determines production (2) HETP (height equivalent per theoretical plate) which determines column length (3) the hold-up per plate which determines plant inventory and time to production (4) the pressure drop per plate which should be as small as possible. The choice of a particular column is invariably a compromise between these factors. The separation in a production column is of course less than it would be at total reflux (no product withdrawal). The concentration at any point in the enriching section can be calculated from the transport equation (see, e.g., London 1961)... 

HETP (Height equivalent per theoretical plate) Random Packings ... 

Height equivalent to a theoretical plate (HETP) A measure of the efficiency of a column usually expressed in millimeters. HETP — LIN, where L is the length of a column and N is the number of theoretical plates. The reciprocal of HETP is also used to describe efficiency and is often expressed by the terms plates per meter. 

Band broadening within the chromatographic column is described as a function of mobile phase linear velocity ( ) by the well known van Deemter equation [5] that relates the height equivalent to the theoretical plate (HETP) to u the lower the HETP, the higher the plate number per unit length of a column. It follows that the highest efficiency is obtained for the shortest HETP. The van Deemter equation is ... 

Since coluriins are constructed in various lengths, it is convenient to have a measure of the efficiency per unit length. This is commonly known as the height equivalent to a theoretical plate (HETP) and is obtained by dividing the number of theoretical plates into the length. 

The efficiency of a system may be expressed as the height-equivalent theoretical plate (HETP) in centimeters (or inches) per plate. The HETP is related to the number of theoretical plates n by... 

With effects causing asymmetrical spreading assumed negligible, the plate height h (or HETP, height equivalent to a theoretical plate) for a gaussian distribution may be defined as variance per unit length of column ... 

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