Determination Of Oxygen Transfer Coefficient Research Articles

Gas pressure intensifying oxygen transfer to significantly improving the bio‐oxidation productivity of whole‐cell catalysis

AbstractOxygen, as a terminal electron acceptor, is an essential substrate in the aerobic bio‐oxidation process, affecting bacterial vitality and bio‐oxidation performance. In this study, a newfangled platform biotechnology of sealed‐oxygen supply bioreactor (SOS‐BR) was developed by improving gas pressure to significantly intensify oxygen transfer rate to resolve the formidable barriers of aerobic catalysis. In virtue of SOS‐BR, the bio‐productivity was greatly improved for three representative substrates (xylose, furfural, and glycerol) bio‐oxidation with the whole‐cell catalysis of Gluconobacter oxydans. The determination of oxygen transfer coefficient (KLα) established an upgraded theoretical dynamic model for gas pressure intensification biosystem. Additionally, viscosity measurement and combined pressure control strategy explained the inflection point phenomenon of productivity and confirmed the intensify mechanism. The smart strategy of significantly intensifying oxygen transfer provided insightful ideas for overcoming the stubborn obstacle of obligate aerobic catalysis, and further promoted the development and industrial practicability of bio‐oxidation.

Determination of oxygen transfer coefficients in HRAP for the two aeration systems: airlift and paddle wheel

Determination of oxygen transfer coefficients in HRAP for the two aeration systems: airlift and paddle wheel

Continuous Determination of Oxygen Transfer Coefficient with an On-Line Respiration Meter

An on-line respiration meter was applied to measure the oxygen transfer coefficient (KLa) continuously in a completely mixed aeration tank. The uniqueness of this respiration meter lies in its ability to measure the actual respiration rate of activated sludge. The calculation of KLa can be carried out continuously with steady-state and discrete non-steady state equations using actual respiration rate and DO in the aeration tank. In an activated sludge pilot plant, the oxygen transfer coefficients were determined under constant and variable loading conditions using the above procedures. The relationship between KLa and air flow was found to be linear but dependent on the wastewater loading characteristic. Under variable loading conditions, the calculated DOs in the aeration tank using the obtained KLa's were more accurate than that using the KLa's estimated from the air flow rate function. The accuracy of separately assumed saturation DO in the activated sludge was confirmed from a linear relationship between DOs in the aeration tank and corresponding actual respiration rates at a constant KLa.

ON THE METHODS FOR THE DETERMINATION OF THE OXYGEN TRANSFER COEFFICIENT IN MECHANICALLY AGITATED VESSELS

Abstract This paper reports on the determination of the overall oxygen transfer coefficient in mechanically agitated vessels. Many variants of the sulfite oxidation method are compared with the dynamic method. A new variant of the sulfite oxidation method, called the reaction time method, is proposed. Overall oxygen mass transfer coefficients were obtained with two probes having significantly different time constants and for various agitation levels. The advantages and disadvantages of the main methods used for the determination of the oxygen transfer coefficient are reviewed and discussed.

Practical guidelines for the determination of oxygen transfer coefficients ( KLa) with the sulfite oxidation method

The sulfite oxidation method was reinvestigated in this work to establish a procedure for the measurement of oxygen transfer coefficients, K L a. Cobalt ion catalysed oxidations, using buffered Na 2SO 3 solutions, were conducted in an aerated baffled tank which was fitted with a turbine impeller, and in a multistage countercurrent bubble column. An empirical procedure to change the cobalt ion catalyst concentration was employed to determine the suitable reaction regime conditions for K L a measurement. In the correct {Co 2+} range, the oxidation rate becomes independent of {Co 2+}, thus permitting the individual experimentor to establish empirically the proper operating conditions. Speed and accuracy in determining the oxidation rate was improved by the use of oxygen gas analysis and mass balance procedures. Investigation of the catalyst induction time demonstrated that the oxygen uptake rate will vary with time during the first 20 to 40 min of the oxidation, requiring that care be taken to establish steady state conditions. Experiments with 1% and 2% carboxymethyl-cellulose solutions showed that the method was also applicable to these viscous systems. The dynamic electrode method was applied in the stirred tank to sulfate solutions of the same ionic strength, yielding comparable results when K L a was less than the inverse electrode time constant. The sulfite method gave a relative error of less than 10% at high K L a. At low extents of absorption in the bubble column, the specific interfacial area a could be measured in addition to K L a, which permitted evaluation of the mass transfer coefficient K L. Guidelines for the experimental determination of K L a are presented.

Stanovení objemového koeficientu přenosu kyslíku zahrnující korekci na skutečné kultivační podmínky.

Stanovení objemového koeficientu přenosu kyslíku zahrnující korekci na skutečné kultivační podmínky.

Method for the determination of oxygen transfer coefficients (KLa) with the correction for the actual cultivation conditions

A method for determination of the volumetric oxygen transfer coefficient KLa from dynamic measurement data under conditions of both excess oxygen and oxygen-limited growth of microorganisms is described. The KLa determination follows from the integrated form of the oxygen balance equation and involves a correction for the actual cultivation conditions during measurement.

Method for the determination of oxygen transfer coefficients (KLa) with the correction for the actual cultivation conditions

AbstractA method for determination of the volumetric oxygen transfer coefficient KLa from dynamic measurement data under conditions of both excess oxygen and oxygen‐limited growth of microorganisms is described. The KLa determination follows from the integrated form of the oxygen balance equation and involves a correction for the actual cultivation conditions during measurement.