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Identification of constant and stable main transition velocity in bubble column reactors

Nedeltchev Stoyan

Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk

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2020

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nr 24

9--27

EN

This work presents new results about the reliable identification of the main transition velocity Utrans-1 in different bubble columns (0.1 – 0.46 m in inner diameter) equipped with several perforated plate gas distributors. Two different gas-liquid systems (air-water and air-therminol LT) have been used. The most important finding in this work is that Utrans-1 (end of the homogeneous regime) occurs at 0.04 m·s-1 irrespective of the operating conditions studied. For the Utrans-1 identification, the following parameters have been used: Kolmogorov and reconstruction entropies, degree of randomness and information entropy.

PL

W pracy przedstawiono nowe wyniki dotyczące wiarygodnej identyfikacji głównej prędkości przejścia Utrans-1 w różnych kolumnach barbotażowych (o średnicy wewnętrznej 0,1 - 0,46 m) wyposażonych w kilka dystrybutorów gazu typu płyta perforowana. Zastosowano dwa różne układy gaz-ciecz (powietrzewoda i powietrze-therminol LT). Najważniejszym odkryciem w tej pracy jest to, że Utrans-1 (koniec reżimu przepływu homogenicznego) występuje dla prędkości 0,04 m·s-1 niezależnie od badanych warunków pracy. Do identyfikacji Utrans-1 wykorzystano następujące parametry: entropię Kołmogorowa, entropię rekonstrukcyjną, stopień losowości oraz entropię informacji.

2

Effect of gas holdup on the efficiency of cyclonic-static microbubble flotation column for oily wastewater treatment

Ning K., Huang G., Xu H., Wu L., Li X., Wang Y.

Environment Protection Engineering

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2018

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Vol. 44, nr 2

5--17

EN

A cyclonic-static microbubble flotation column of a novel construction was used in oil-water separation fields and has high efficiency for oil-water separation. The gas holdup is a key parameter for the evaluation of the performance of a flotation column. The gas holdup, closely related to the bubble size, bubble velocity and superficial gas velocity, is one of the most important parameters characterizing the hydrodynamics of a bubble column. The effect of gas holdup in a cyclonic-static microbubble flotation column was investigated. In addition, several operating parameters such as the circulating pressure, superficial gas velocity, and frother consumption were also investigated. The gas holdup was positively correlated to the superficial gas velocity. The gas holdup of clean water and oil wastewater increased along with the increase of the frother consumption. The separation mechanism of cyclonic-static microbubble flotation column was analyzed.

3

Axial mixing in the prochem multi-stage mechanically - agitated gas/liquid contactor

Al Taweel A. M., Cheng Y. H., Ghaly A. E.

Applied Mechanics and Engineering

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1999

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Vol. 4, no 4

673-698

EN

The axial mixing characteristics of a pilot-scale multi-stage mechanically-agitated gas/liquid contactor (the PROCHEM column) was investigated over a wide range of design and operating conditions. The experimental results, obtained using the dynamic response method, were analyzed using three models. The tanks in series model were identified as the one most suitable for describing the axial mixing in this type of column and a general correlation describing the effect of various design and operating conditions on the axial mixing characteristics was developed. A comparison with other multi-phase column contactors indicates that the axial mixing characteristics of this column are superior to those of unagitated bubble columns operating under similar conditions. Means for further improvement in column performance were also identified.