Factors Affecting HETP

Packing size and type (Secs. 8.1.2,8.1.4, and 8L1.10). Generally, packing efficiency increases (HETP decreases) dien 

Liquid and vapor loads have little effect on random packings HETP. 

Distribution (Sec. 9.2). Both liquid and vapor maldistribution have a major detrimental effect on packing efficiency. 

Some tests fay Koshy and Rukovena (110,111) with aqueous, bi -relative-volatility systems (a 2) gave much lower random packing efficiencies at high and low L(V than close to total reflux. They interpreted the results as an LfV ratio effect however, underwetting (below) can also explain these data. 

Pressure. Generally pressure has little effect on HETP of both random (117,118) and structured (3,32) packing, at least above 1 to 2 psia. 

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A prerequisite to any interpolation of packing data is thorough familiarity with the factors that affect HETP. These factors are listed in Sec. 9.1.3, and elaborated on in various other sections (which are re-... 

Other oxides of nitrogen are present in these systems, and they affect the single stage enrichment factor a = ( N/ N)iiquid/( N/ N)gas as well as the interphase transfer rate as measured by the height of the column equivalent to a theoretical plate (HETP). 

While A is a useful concept to compare the efficiency of separation among columns, or between laboratories, it is difficult to use to assess the factors that affect that efficiency. This is due to the fact that it refers to the behavior of a single component during the separation process, and is unsuited to describing the separation of two components or the resolving power of a capillary. A more useful parameter is the height equivalent of a theoretical plate (HETP). ... 

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