Performance of a reciprocating-plate extraction column

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Abstract

An open type of reciprocating-plate extraction column was developed, and it is proposed that the scaling up of such a column should be straightforward; that is, the height of an equivalent theoretical stage (H.E.T.S.) and the throughput per unit area should be independent of the diameter of the column.

Plates having 5/8-in.–diameter holes and 62.8% free space were selected to minimize the resistance to countercurrent flow in the column. With this design low H.E.T.S. values were achieved at throughputs much higher than those reported for other columns. Thus for two systems the present column was shown to require the lowest volume of column to accomplish a given extraction job. Data were obtained in a 3-in.–diameter column on two systems, methyl isobutyl ketone-acetic acid-water and o-xylene-acetic acid-water. Throughputs studied on the first system ranged from 547 to 1,837 gal./hr./sq. ft., and the corresponding minimum H.E.T.S. values achieved were 4.3 and 7.5 in. respectively. For the second system minimum H.E.T.S. values of 7.7 and 9.1 in. were attained at throughputs of 424 and 804 gal./hr./sq. ft. respectively.

Extraction column design procedures are discussed. The fabrication of the reciprocating-plate column is relatively simple, and this should encourage its use first in pilot-scale sizes and ultimately in large-scale columns.

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