The specific interfacial area in external-circulation-loop airlifts and a bubble column-II. Carboxymethyl cellulose/sulphite solution

• Published in: Chemical engineering science Vol. 42; no. 12; pp. 2825 - 2832
• Main Authors: Popović, Milan, Robinson, Campbell W.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1987; Elsevier
• Subjects: Biological and medical sciences; Biotechnology; Fundamental and applied biological sciences. Psychology; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Design; Gas liquid interface; Measurement; Hydrodynamic properties; Gas holdup; Sulfites; Bioreactor; Cellulose(carboxymethyl); Non newtonian liquid; Bubble column; Air lift; Interfacial area
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/0009-2509(87)87049-5

Specific gas-liquid interfacial areas and gas hold-ups in the riser and downcomer sections as well as the liquid circulating velocity were studied using highly viscous pseudo-plastic solutions of carboxymethyl cellulose (CMC). The specific interfacial area was measured by the chemical reaction method (sulphite oxidation). The measurements were carried out in two sizes of external-circulation-loop airlift (ECL-AL) having downcomer-to-riser cross-sectional area ratios ( A d/ A r) of 0.111 and 0.444. Parallel studies in a bubble-column-type fermentor ( A d/ A r = 0) were performed for comparison. All the parameters studied are greatly affected by A d/ A r and the gas superficial velocity, u GR, while the influence of the effective viscosity, η eff, varies from parameter to parameter. A correlation for the specific interfacial area considering the effect of u GR, A d/ A r and η eff is proposed.