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Mass transfer characteristics of multiple-impeller fermenters for their design and scale-up

Paper ID Volume ID Publish Year Pages File Format Full-Text
3535 174 2012 11 PDF Available
Title
Mass transfer characteristics of multiple-impeller fermenters for their design and scale-up
Abstract

Mechanically agitated gas–liquid contactors are frequently used in the chemical, food and biochemical industries as fermenters and as hydrogenation or chlorination reactors. However wide the usage of such vessels is, their design is not based on chemical engineering data, but is still rather empirical. Thus, it is highly desirable to have a tool for the rational design of agitated gas–liquid contactors that is based on fundamental chemical engineering parameters that are transferable to other systems and operating conditions. Focusing on liquid film-controlled processes and using the data from fermenters of different scales, we develop kLa correlations that are suitable for scale-up.First, we discuss the way how to determine the proper experimental kLa values, which are not distorted by other equipment parameters as the gas residence time is. We demonstrate the possible kLa distortion on the pilot-plant experimental data by the comparison of the results obtained by two different experimental techniques. Further, we present physically correct kLa data for coalescent (pure water) and fully non-coalescent (sodium sulphate solution) batches. The data are presented both for laboratory and for pilot-plant fermenters. We identify the process parameters, the values of which are dependent on the vessel scale when operated under the same power input per unit volume, and, using these parameters, we develop common kLa correlations suitable to describe the data for various scales of the vessel.The correlations developed reduce the uncertainty in predicting the volume of industrial scale fermenters from almost 1/2 to 1/4 of their total volume, thereby enabling significant reductions in both the initial costs and operating costs.

► Fermenters scale-up based on volumetric mass transfer coefficient, kLa, is presented. ► Experimental kLa data for pilot-plant fermenter are presented. ► Process parameters are identified, the value of which depends on the fermenter size. ► The kLa correlations suitable for scaling-up are developed. ► The uncertainty is significantly reduced in the volume of the designed industrial fermenter.

Keywords
DM, Classical Dynamic Method; DPM, Dynamic Pressure Method; OTR, oxygen transfer rateFermenter; Mass transfer; Mass transfer correlations; Mixing; Multiple-impeller; Scale-up; Volumetric mass transfer coefficient
First Page Preview
Mass transfer characteristics of multiple-impeller fermenters for their design and scale-up
Publisher
Database: Elsevier - ScienceDirect
Journal: Biochemical Engineering Journal - Volume 69, 15 December 2012, Pages 17–27
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering