Control of dispersed-phase volume fraction in multistage extraction columns

C. Tsouris, L. L. Tavlarides

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

An ultrasonic technique is employed for the control of the dispersed-phase volume fraction (holdup) in liquid-liquid column extractors. The technique is tested for a multistage extractor of pilot-plant scale where the holdup is continuously monitored in all stages. The average holdup in the column, calculated from the profile, is considered as the control variable, while the agitation speed is used as the manipulated variable. The volumetric flow rates are the other operating conditions and are considered as disturbance variables. Adaptive and nonadaptive control are demonstrated by applying the Dahlin algorithm. By inspection of the holdup profile, information about the operation of the column with respect to flooding or phase inversion is provided. This information is processed for driving the holdup set point in the proximity of flooding where optimum operation usually occurs. For the first time, holdup is controlled over a wide range of values from as low as 10% to as high as 90% of the holdup value at flooding. The importance of the ultrasonic technique for the control of extraction columns is that it can be readily applied for safe operation at optimum conditions for any type of existing or new extractors.

Original languageEnglish
Pages (from-to)2857-2865
Number of pages9
JournalChemical Engineering Science
Volume46
Issue number11
DOIs
StatePublished - 1991
Externally publishedYes

Funding

Arknowledgements-The authors would like to acknowledge the assistance of Mr. Richard Gunther during the execution of the experiments. Partial financial support by the Department of Chemical Engineering and Materials Science (assistantship for CT.), Phaedron Technologies, Inc., industrial grant, and the National Science Foundation Grant CTS-9017138 are gratefully acknowledged.

FundersFunder number
Department of Chemical Engineering and Materials Science
Phaedron Technologies, Inc.
National Science FoundationCTS-9017138

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