Volumetric mass transfer coefficient in viscous liquid in mechanically agitated fermenters. Measurement and correlation

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22340%2F17%3A43914093" target="_blank" >RIV/60461373:22340/17:43914093 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0009250917302488" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0009250917302488</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.ces.2017.04.006" target="_blank" >10.1016/j.ces.2017.04.006</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Volumetric mass transfer coefficient in viscous liquid in mechanically agitated fermenters. Measurement and correlation

Popis výsledku v původním jazyce

In the industrial fermentation processes, most liquids are non-coalescent and often exhibit increased viscosity. However, due to the limitations of most measurement methods, there is a lack of reliable data for predicting volumetric mass transfer coefficients (k(L)a) for viscous batches, especially under high dissipated energies, as the accurate determination of oxygen concentration profile in viscous liquids is not as easy as in low viscosity ones. Our goal is to develop reliable technique for k(L)a determination in viscous liquids and to establish suitable correlation shapes to describe k(L)a data. We used the dynamic pressure method (DPM), the experimental set-up of which has been modified for the measurement in viscous liquids. Dissolved oxygen (DO) probes were placed in bypass measuring cells. This set up brings well defined transient characteristics of DO probes, which is crucial for correct k(L)a evaluation. Measurements were conducted in two phase multiple-impeller fermenters with a non-coalescent viscous Newtonian batch under a wide range of experimental conditions and in the apparatuses of two scales. Using pure oxygen as gas phase, it was confirmed that DPM yields k(L)a&apos;s independent of the driving force of absorption even in viscous batch. The improved set up of DPM enabled to use also optical DO probes as well as polarographic ones. It was confirmed that optical DO probe can be used for k(L)a values up to 0.4 s(-1). Based on the experimental data, correlations were developed to predict k(L)a in industrial fermenters. Standard correlation k(L)a = 2.99 . 10(-3).(P-g /V-L)(0.891)vs(0.556) with standard deviation, SD, 30%, based on gassed power input P-g and superficial gas velocity v(s), has low standard deviation but it is scale specific. On the other hand, when the term of impeller tip speed (ND) is used instead of P-g, predicted data exhibit neither over nor under-estimation of kip for particular apparatus scale; so the effect of the vessel scale is properly described using this term. In addition, the impeller power number P-o was found to be a reliable predictor of k(L)a in a common correlation for various impeller types, when used together with the impeller tip speed term. The correlation k(L)a = 0.295.(ND)(2.083)vs(0.461) p(o)(0.737) with SD 28% suggested in this work can&apos;be used fOr 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 viscous liquid in mechanically agitated fermenters. Measurement and correlation

Popis výsledku anglicky

In the industrial fermentation processes, most liquids are non-coalescent and often exhibit increased viscosity. However, due to the limitations of most measurement methods, there is a lack of reliable data for predicting volumetric mass transfer coefficients (k(L)a) for viscous batches, especially under high dissipated energies, as the accurate determination of oxygen concentration profile in viscous liquids is not as easy as in low viscosity ones. Our goal is to develop reliable technique for k(L)a determination in viscous liquids and to establish suitable correlation shapes to describe k(L)a data. We used the dynamic pressure method (DPM), the experimental set-up of which has been modified for the measurement in viscous liquids. Dissolved oxygen (DO) probes were placed in bypass measuring cells. This set up brings well defined transient characteristics of DO probes, which is crucial for correct k(L)a evaluation. Measurements were conducted in two phase multiple-impeller fermenters with a non-coalescent viscous Newtonian batch under a wide range of experimental conditions and in the apparatuses of two scales. Using pure oxygen as gas phase, it was confirmed that DPM yields k(L)a&apos;s independent of the driving force of absorption even in viscous batch. The improved set up of DPM enabled to use also optical DO probes as well as polarographic ones. It was confirmed that optical DO probe can be used for k(L)a values up to 0.4 s(-1). Based on the experimental data, correlations were developed to predict k(L)a in industrial fermenters. Standard correlation k(L)a = 2.99 . 10(-3).(P-g /V-L)(0.891)vs(0.556) with standard deviation, SD, 30%, based on gassed power input P-g and superficial gas velocity v(s), has low standard deviation but it is scale specific. On the other hand, when the term of impeller tip speed (ND) is used instead of P-g, predicted data exhibit neither over nor under-estimation of kip for particular apparatus scale; so the effect of the vessel scale is properly described using this term. In addition, the impeller power number P-o was found to be a reliable predictor of k(L)a in a common correlation for various impeller types, when used together with the impeller tip speed term. The correlation k(L)a = 0.295.(ND)(2.083)vs(0.461) p(o)(0.737) with SD 28% suggested in this work can&apos;be used fOr 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

Chemical Engineering Science

ISSN

0009-2509

e-ISSN

—

Svazek periodika

170

Číslo periodika v rámci svazku

October 12 2017

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

13

Strana od-do

451-463

Kód UT WoS článku

000407655100041

EID výsledku v databázi Scopus

2-s2.0-85018644124