ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
One of the important factors affecting the efficiency of vapor-liquid contacting operations is the relationship between available interfacial area and contact time.Because of the difficulties in measuring these quantities, little information has heretofore been made available on them. Previous studies have been confined to extreme over-simplifications of the turbulent type of contacting taking place in fractionation devices. The present investigation consisted of the determination of interfacial area and contact time for the formation of air bubbles submerged in water and aqueous solutions. The bubbles were produced at single vertical slots and rose through a flowing liquid. In order to complete the study on physical contacting, a companion study is concerned with vapor-liquid behavior in the forth and entrainment zones. The experimental technique in this study involved taking high-speed motion pictures of the bubbling action. Measurements of the area and volume of bubbles were made at intervals during the course of their growth, and values of total contact time and average interfacial area per unit volume of vapor are presented.It was found that both the average interfacial area per unit volume of vapor a and the total contact time tm were primarily affected by the head of flowing liquid on the slot. Below slot submergence of approximately 2.5 in. of liquid, interfacial area was shown to decrease with increasing slot submergence and increasing slot area. Above 2.5 in. of liquid, interfacial area was a function of skirt clearance, liquid viscosity, and surface tension.Total contact time was found to increase with increasing slot submergence and to decrease with increasing vapor rate and skirt clearance.Through the use of an integrated mass transfer-rate equation, the terms a and tm can be used in conjunction with the appropriate mass transfer coefficient for predicting the point efficiencies on bubble-cap plates.
Additional Material:
13 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690030105
