Volumetric mass transfer coefficient in the fermenter agitated by Rushton turbines of various diameters in viscous batch

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22340%2F17%3A43914111" target="_blank" >RIV/60461373:22340/17:43914111 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0017931017324067" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0017931017324067</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.ijheatmasstransfer.2017.07.112" target="_blank" >10.1016/j.ijheatmasstransfer.2017.07.112</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Volumetric mass transfer coefficient in the fermenter agitated by Rushton turbines of various diameters in viscous batch

Popis výsledku v původním jazyce

In cases of aerobic fermentations, the apparatuses for their industrial performance are designed also from the viewpoint of sufficient oxygen supply to avoid oxygen limitation of biomass, i.e. to provide sufficient oxygen gas-liquid transfer rate. For biochemical processes with high respiration rate, the oxygen demand of which is also high, mechanically agitated vessels are usually used. In comparison with airlift reactors and bubble columns, these equipments enable to reach higher oxygen gas-liquid transfer rates, i.e., they reach higher values of volumetric mass transfer coefficient, k(L)a. Due to the hydrodynamic complexity of mechanically agitated gas-liquid systems, the k(L)a predictions from first principles are not reliable yet, and, therefore, experimental data are needed for rational design of fermenters. Most fermentation broths are of increased viscosity, for which the lack of reliable k(L)a data exists due to the limitations of most measurement methods. We recently suggested and verified the methodology to obtain reliable experimental k(L)a data in viscous batch even for high dissipated energies. We used the dynamic pressure method (DPM), the experimental set-up of which was modified for the measurement in viscous batch. In our previous work, we provided fairly large k(L)a database to establish suitable correlation shapes to describe kLa dependencies on process conditions in viscous liquids. Now, we focused on the effect of impeller diameter on transport characteristics because in cases of shear stress sensitive biomass this parameter strongly affects the fermentation efficiency. The measurements were conducted in multiple-impeller fermenters, both of laboratory and of pilot-plant scale, using viscous Newtonian batch under a wide range of experimental conditions (impeller frequencies, gas flow-rates, impeller diameters). Rushton turbines of various diameters were used. Based on the experimental data, the correlations were developed to predict kLa in industrial fermenters. Standard correlation k(L)a = 0.0024 (P-TOT)(0.86)v(s)(4.49) with SD 23%, based on gassed power input P-TOT and superficial gas velocity v(s), has low standard deviation. On the other hand, when the term of impeller tip speed (ND) is used instead of P-TOT, predicted data have a higher standard deviation k(L)a = 0.29 (ND)(2.15)v(s)(4.27) with SD 37%, but when this correlation is modified taking into account the D/T ratio, the standard deviation decreases significantly. The correlation k(L)a = 1.14 (ND)(2.23)v(s)(0.27)(D/T)(1.3) with SD 25% suggested in this work can be used for the fairly accurate design of industrial fermenters. Both the experimental technique and the correlation shape are ready to be used to obtain the design tool for other batches with various viscosities.

Název v anglickém jazyce

Volumetric mass transfer coefficient in the fermenter agitated by Rushton turbines of various diameters in viscous batch

Popis výsledku anglicky

In cases of aerobic fermentations, the apparatuses for their industrial performance are designed also from the viewpoint of sufficient oxygen supply to avoid oxygen limitation of biomass, i.e. to provide sufficient oxygen gas-liquid transfer rate. For biochemical processes with high respiration rate, the oxygen demand of which is also high, mechanically agitated vessels are usually used. In comparison with airlift reactors and bubble columns, these equipments enable to reach higher oxygen gas-liquid transfer rates, i.e., they reach higher values of volumetric mass transfer coefficient, k(L)a. Due to the hydrodynamic complexity of mechanically agitated gas-liquid systems, the k(L)a predictions from first principles are not reliable yet, and, therefore, experimental data are needed for rational design of fermenters. Most fermentation broths are of increased viscosity, for which the lack of reliable k(L)a data exists due to the limitations of most measurement methods. We recently suggested and verified the methodology to obtain reliable experimental k(L)a data in viscous batch even for high dissipated energies. We used the dynamic pressure method (DPM), the experimental set-up of which was modified for the measurement in viscous batch. In our previous work, we provided fairly large k(L)a database to establish suitable correlation shapes to describe kLa dependencies on process conditions in viscous liquids. Now, we focused on the effect of impeller diameter on transport characteristics because in cases of shear stress sensitive biomass this parameter strongly affects the fermentation efficiency. The measurements were conducted in multiple-impeller fermenters, both of laboratory and of pilot-plant scale, using viscous Newtonian batch under a wide range of experimental conditions (impeller frequencies, gas flow-rates, impeller diameters). Rushton turbines of various diameters were used. Based on the experimental data, the correlations were developed to predict kLa in industrial fermenters. Standard correlation k(L)a = 0.0024 (P-TOT)(0.86)v(s)(4.49) with SD 23%, based on gassed power input P-TOT and superficial gas velocity v(s), has low standard deviation. On the other hand, when the term of impeller tip speed (ND) is used instead of P-TOT, predicted data have a higher standard deviation k(L)a = 0.29 (ND)(2.15)v(s)(4.27) with SD 37%, but when this correlation is modified taking into account the D/T ratio, the standard deviation decreases significantly. The correlation k(L)a = 1.14 (ND)(2.23)v(s)(0.27)(D/T)(1.3) with SD 25% suggested in this work can be used for the fairly accurate design of industrial fermenters. Both the experimental technique and the correlation shape are ready to be used to obtain the design tool for other batches with various viscosities.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20401 - Chemical engineering (plants, products)

Projekt

<a href="/cs/project/GA15-21715S" target="_blank" >GA15-21715S: Experimentální studie přenosu hmoty kapalina-plyn za přítomnosti pevných částis a ve viskózní vsádce</a><br>

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

International Journal Heat Mass Transfer

ISSN

0017-9310

e-ISSN

—

Svazek periodika

115

Číslo periodika v rámci svazku

December 2017

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

11

Strana od-do

856-866

Kód UT WoS článku

000413131200083

EID výsledku v databázi Scopus

2-s2.0-85026532259