J. Mayrhoferová

Bio: J. Mayrhoferová is an academic researcher. The author has contributed to research in topics: Order of reaction & Aqueous solution. The author has an hindex of 1, co-authored 1 publications receiving 69 citations.

Mass-Transfer Rates in Gas-Liquid Absorbers and Reactors

Abstract: Publisher Summary At the heart of the liquid-phase processes, gas scrubbing process, manufacturing of pure products, and biological systems, there exists the absorber or the reactor of a particular configuration best suited to the chemical absorption or reaction being carried out. Its selection, design, sizing, and performance depend on the hydrodynamics and axial dispersion, mass and heat transfer, and reaction kinetics. This chapter focuses on the subject of mass transfer with chemical reaction. It presents the techniques, results, and opinions on mass-transfer coefficients and interfacial areas in most types of absorbers and reactors. To study gas–liquid mass-transfer phenomena, it is convenient to consider steady-state situations in which the composition of the gas and the liquid are statistically constant when averaged over time in a specified region, such as a short, vertical slice of a tubular column or the entire volume of a single-compartment agitated vessel. Useful predictions have been developed for describing the behavior of complicated systems, using highly simplified models that simulate the situation for practical purposes without introducing a large number of parameters. The procedure differs depending on whether physical or chemical absorption is involved.

Bubble column bioreactors

Abstract: The photographic and electrical conductivity methods to measure the structure of two phase flow, especially bubble size, bubble frequency, local gas hold-up and, for the latter, the bubble velocity are described.

Mechanism of mass transfer from bubbles in dispersions: Part II: Mass transfer coefficients in stirred gas–liquid reactor and bubble column

Abstract: Experimental data on the average mass transfer liquid film coefficient ( k L ) in an aerated tank stirred by Rushton turbine and in bubble column are presented. Liquid media were used as 0.8 M sodium sulphite solution, pure or with the addition of Sokrat 44 (copolymer of acrylonitrile and acrylic acid) or short-fiber carboxymethylcellulose (CMC) for the Newtonian and long-fiber CMC for the non-Newtonian viscosity enhancement and ocenol ( cis -9-octadecen-1-ol) or polyethylenglycol (PEG) 1000 for surface tension change. Volumetric mass transfer coefficient ( k L a ) and specific interfacial area ( a ) were measured by the Danckwerts’ plot method. Coefficients k L measured by pure oxygen absorption in pure sulphite solution and Newtonian viscous liquids are well fitted by the “eddy” model in the form of k L = 0.448 ( e v / ρ ) 0.25 ( D / v ) 0.5 with a mean deviation of 20%. Surface-active agents (ocenol and PEG) and non-Newtonian additive (long-fiber CMC) reduced k L value significantly but their effect was not described satisfactorily neither by surface tension nor by surface pressure. It is shown that the decisive quantity to correlate k L in the stirred tank and bubble column is power dissipated in the liquid phase rather than the bubble diameter and the slip velocity. Absorption of air did not yield correct k L data, which did not depend on or slightly decreased with increasing power. This is due to the application of an improper gas phase mixing model for absorption data evaluation.

Review of Methods for the Measurement of Oxygen Transfer in Microbial Systems

Abstract: A review of the methods for the measurement of oxygen transfer rates and coefficients in the absence and presence of microorganisms is presented here with their basic assumptions and corresponding procedures. Considerable space is devoted to unsteady-state methods which include many modifications. The importance of steady-state methods in microbial systems is stressed. Recent developments show ways of avoiding some inherent mistakes involved in both steady-state and dynamic methods. Advantages and disadvantages of the methods are critically discussed and suggestions are made for their application and further development.