Packed Bed flooding.pdf - Youngstown State University's Personal ...
Packed Bed flooding.pdf - Youngstown State University's Personal ...
Packed Bed flooding.pdf - Youngstown State University's Personal ...
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14-104 EQUIPMENT FOR DISTILLATION, GAS ABSORPTION, PHASE DISPERSION, AND PHASE SEPARATION<br />
require careful technique. Satisfactory photographic methods have<br />
been developed by Vermenlen, Williams, and Langlois [Chem. Eng.<br />
Progr., 51, 85 (1955)] and by Calderbank [Trans. Instn. Chem. Engrs.,<br />
36, 443 (1958)] and are described by these authors. Calderbank’s<br />
technique resulted in particularly precise measurements that permitted<br />
a good estimation of the surface area of the dispersed bubbles.<br />
Methods of Gas Dispersion The problem of dispersing a gas in<br />
a liquid may be attacked in several ways: (1) The gas bubbles of the<br />
desired size or which grow to the desired size may be introduced<br />
directly into the liquid; (2) a volatile liquid may be vaporized by either<br />
decreasing the system pressure or increasing its temperature; (3) a<br />
chemical reaction may produce a gas; or (4) a massive bubble or stream<br />
of gas is disintegrated by fluid shear and/or turbulence in the liquid.<br />
Spargers: Simple Bubblers The simplest method of dispersing<br />
gas in a liquid contained in a tank is to introduce the gas through an<br />
open-end standpipe, a horizontal perforated pipe, or a perforated<br />
plate at the bottom of the tank. At ordinary gassing rates (corresponding<br />
to the jet regime), relatively large bubbles will be produced<br />
regardless of the size of the orifices.<br />
Perforated-pipe or -plate spargers usually have orifices 3 to 12 mm<br />
in diameter. Effective design methods to minimize maldistribution<br />
are presented in the fifth edition of this handbook, p. 5–47, 1973, and<br />
by Knaebel [Chem. Eng., 116 (Mar. 9, 1981)]. For turbulent flow conditions<br />
into the sparger, the following relationship will allow design of<br />
a perforated-pipe sparger for a given degree of maldistribution provided<br />
N h > 5 and length/diameter