The effect of plate wetting characteristics on pulse column extraction efficiency

Liquid‐liquid extraction of acetic acid from the methyl isobutyl ketone‐water system was studied as a function of plate wetting characteristics and other variables in a pulsed perforated‐plate extraction column. Various combinations of stainless steel plates and polyethylene plates were used with different directions of solute transfer at a constant throughput of 82.6 lb. total flow/(min.) (sq. ft. column area) and with other operating variables in the following range: Frequency — 16 to 117.1 c./min. Amplitude — 0.492 and 0.973 in. W/K flow ratio — 0.46 to 2.8 lb. water/lb. ketone The plate wetting characteristics were found to affect the column extraction efficiency when the solute transfer was from the continuous ketone phase to water. An all polyethylene plate arrangement provided the best efficiency (H. T. U.oc = 4.1 in.) while an all stainless steel plate arrangement was less efficient (H. T. U.oc = 6.1 in.) under the most favorable operating conditions. A combination of these two arrangements in the column produced efficiencies midway between the all‐plastic plate arrangement and the all‐stainless steel plate arrangement. Within the column flooding limits the extraction efficiency did not seem to be affected by the plate wetting characteristics when the solute transfer was from water to the continuous ketone phase.