REMOVAL OF EMULSIFIED OIL PARTICLES BY DISPERSED AIR FLOTATION

• Published in: JOURNAL OF CHEMICAL ENGINEERING OF JAPAN Vol. 13; no. 5; pp. 385 - 389
• Main Authors: SATO, YUJI, MURAKAMI, YASUHIRO, HIROSE, TSUTOMU, URYU, YOSHIFUMI, HIRATA, Kon
• Format: Journal Article
• Language: English
• Published: Tokyo The Society of Chemical Engineers, Japan 01.01.1980; Taylor & Francis Group
• ISSN: 0021-9592; 1881-1299
• DOI: 10.1252/jcej.13.385

Dilute emulsified particles (C≈300g⋅m-3, DP≈8μm) of heavy oil A were removed in a 65 mm-diameter, 0.32 m-deep column with a solution of pH 4 which minimized double-layer repulsion. Firstly, flotation by bubbling through glass frits of three different pore sizes shows that the removal rate is proportional to the oil concentration to the first order at low gas velocity (0.01≤ Ug≤0.05cm⋅s-1) and to the second order at high gas velocity (0.1≤Ug≤3cm⋅s-1). This fact implies that the predominant rate step is oil particle-bubble collision in the former region and particle-particle collision in the latter. Mechanical agitation by a paddle gives the same removal rate as bubbling in the high gas velocity region when the power consumption per unit volume is the same. This fact implies that the role of bubbling there is to give adequate turbulence to the liquid. Secondly, the bubble diameter was changed from 40 pm to 2 mm under the mechanism of bubbleparticle collision by electrolysis, dissolved and bubbling air flotation. With increasing bubble diameter, the collection efficiency decreases rapidly (≈to the -2 power) for small bubbles and much more gradually for large bubbles. This trend coincides with the existing and proposed trajectory theories.