scholarly journals Jet aeration as alternative to overcome mass transfer limitation of stirred bioreactors

2018 ◽  
Vol 18 (4) ◽  
pp. 244-253 ◽  
Author(s):  
Sebastian Weber ◽  
Sebastian Schaepe ◽  
Stephan Freyer ◽  
Michael-Helmut Kopf ◽  
Christian Dietzsch
Keyword(s):  
Mass Transfer ◽  
Mass Transfer Limitation ◽  
Stirred Bioreactors

scholarly journals Jet aeration as alternative to overcome mass transfer limitation of stirred bioreactors

2018 ◽  
Vol 90 (9) ◽  
pp. 1250-1250
Author(s):  
S. Weber ◽  
S. Schaepe ◽  
M.-H. Kopf ◽  
S. Freyer ◽  
C. Dietzsch
Keyword(s):  
Mass Transfer ◽  
Mass Transfer Limitation ◽  
Stirred Bioreactors

scholarly journals The Impact of Iron Oxide Concentration on the Performance of Molten Oxide Electrolytes for the Production of Liquid Iron Metal

2019 ◽  
Vol 51 (1) ◽  
pp. 365-376
Author(s):  
Jan Wiencke ◽  
Hervé Lavelaine ◽  
Pierre-Jean Panteix ◽  
Carine Petitjean ◽  
Christophe Rapin
Keyword(s):  
Mass Transfer ◽  
Iron Oxide ◽  
Liquid Iron ◽  
Mass Transfer Limitation ◽  
Oxide Concentration ◽  
Ohmic Drop ◽  
Geometrical Form ◽  
Flow Through ◽  
Molten Oxide ◽  
The Impact

AbstractThe effect of iron oxide concentration on the conductive behavior of a molten oxide electrolyte has been investigated at 1823 K using stepped linear scan voltammetry. To maximize the current flow through the electrolyte the ohmic drop in the cell was minimized by shortening the electrode distance. The acquired current was then interpreted by means of an ohmic drop correction, taking into account the conductivity of the alumina-silicate electrolyte and the geometrical form factor of the cell. Via this methodology, a mass transfer limitation in dependence of the iron oxide concentration was identified. This mass transfer limitation vanishes above 7 wt pct of iron oxide where charge transfer starts to be limited solely by electrochemical reaction kinetics. In the analyzed range of concentration, an impact of iron oxide on electronic conduction was not measurable. In addition to these findings, the faradaic yield of the anode half-reaction was determined by the life-measure of O2-production. Hereby, a domain of an anodic yield close to 100 pct for various iron oxide concentrations was identified. Based on these findings, suitable conditions for the electrochemical production of liquid iron were determined.

Mass transfer limitation as a tool to enhance the enantiomeric excess in the enzymatic synthesis of chiral cyanohydrins

2001 ◽  
Vol 15 (4-6) ◽  
pp. 111-121 ◽  
Author(s):  
Pieter Jan Gerrits ◽  
Wouter F Willeman ◽  
Adrie J.J Straathof ◽  
Joseph J Heijnen ◽  
Johannes Brussee ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Enzymatic Synthesis ◽  
Enantiomeric Excess ◽  
Mass Transfer Limitation

Mass transfer limitation of photosynthesis of coral reef algal turfs

2006 ◽  
Vol 151 (2) ◽  
pp. 435-450 ◽  
Author(s):  
Robert C. Carpenter ◽  
Susan L. Williams
Keyword(s):  
Mass Transfer ◽  
Coral Reef ◽  
Mass Transfer Limitation ◽  
Algal Turfs

A Three-Dimensional Transient Model of Two-Phase Mass Transfer in Anode Side of Passive Direct Methanol Fuel Cells

2011 ◽  
Vol 233-235 ◽  
pp. 2615-2618 ◽  
Author(s):  
Yue Ping Chen ◽  
Hang Guo ◽  
Fang Ye ◽  
Chong Fang Ma
Keyword(s):  
Mass Transfer ◽  
Fuel Cells ◽  
Direct Methanol Fuel Cells ◽  
Three Dimensional ◽  
Anode Side ◽  
Two Phase ◽  
Mass Transfer Limitation ◽  
Drift Flux Model ◽  
Direct Methanol ◽  
Methanol Fuel Cells

A three-dimensional, two-phase, multiple-component, unsteady model for the anode side of passive direct methanol fuel cells is presented in this work. The model is formed by a drift-flux model and can capture in-plane distributions of species along different directions in the cell. After grid independency test, this model is used to investigate numerically transport behaviors in the anode of liquid feed direct methanol fuel cells. The results illustrate the feasibility of the passively delivering methanol to the electrochemical reaction site, and characterize the relevant transport phenomena. Moreover, the evolution of species concentration, velocities along different directions in the cell and the mass transfer limitation were also presented. The three-dimensional model is valuable for understanding and predicting mass transfer in passive direct methanol fuel cells.

Taking mass transfer limitation into account during ozonation of pollutants reacting fairly quickly

2004 ◽  
Vol 49 (4) ◽  
pp. 25-30 ◽  
Author(s):  
H. Benbelkacem ◽  
S. Mathé ◽  
H. Debellefontaine
Keyword(s):  
Mass Transfer ◽  
Batch Reactor ◽  
Kinetic Regime ◽  
Mass Balances ◽  
Fast Reaction ◽  
Mass Transfer Limitation ◽  
Intermediate Regime ◽  
Gas Concentration ◽  
By Products ◽  
Slow Kinetic

Various situations observed when oxidizing organic compounds via ozone in a semi-batch reactor are illustrated. The resistance to the transfer of ozone from gas to liquid is accounted for using the film model. The mass balances are numerically solved simultaneously within the reactor and within the film to produce time dependent profiles of concentrations, Hatta, enhancement and depletion factors. Firstly, theoretical profiles are exemplified for various kinetic regimes from slow to fast; reaction occurs either in the bulk, in the film or in both. This shows the drastic importance of the shapes of the gas concentration profiles - both at the exit of the reactor and in the liquid phase - in determining the regime. Then, a typical example dealing with fumaric acid ozonation is shown. Firstly, the acid itself oxidizes rapidly producing an intermediate regime: part of the reaction occurs within the film, part within the bulk and the rate constant can be determined. Then, the by-products oxidize more slowly producing a typical regime: reaction occurs within the bulk, the concentration of dissolved ozone is almost 0 and the mass transfer coefficient can be determined. Finally, when all organics have oxidized, the self-decomposition of ozone governs a slow kinetic regime: the concentration of dissolved ozone is close to equilibrium.

Conversion rate and mass transfer limitation in trickle bed reactors in the presence of a fast reaction

2004 ◽  
Vol 59 (22-23) ◽  
pp. 5411-5416 ◽  
Author(s):  
M. Banchero ◽  
L. Manna ◽  
S. Sicardi ◽  
J.G. Boelhouwer ◽  
M.I. Urseanu ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Conversion Rate ◽  
Fast Reaction ◽  
Mass Transfer Limitation ◽  
Trickle Bed Reactors ◽  
Trickle Bed
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