Oxygen Transfer Rate OTR

Dynamic methods during the process using Po electrodes 

Combined methods using biological test systems 

The Cu - or especially the Co-catalyzed oxidation of sulphite (Cooper, Fernstrom, and Miller, 1944 Reith, 1968) is thought to be suitable for estimating the OTR in comparing and designing gas-liquid (G L) reactors only under similar physical conditions as bioprocessing. Mass transport occurring simultaneously with a chemical reaction is a theoretical problem that results it is dealt with in Sect. 4.4. 

According to the theory of mass transport, the OTR depends on the following quantities. 

Beyond this physical method using photography or light scattering for measuring a, the chemical method based on sulfite oxidation is often successfully used despite disadvantages due to different fluid properties. According to the theory of mass transfer with simultaneous chemical reaction, A can be calculated from 

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Aerator type Materials of constmction Oxygen transfer efficiency, OTE, % Oxygen transfer rate, OTR, g/(W-h)... 

Oxygen transfer rate (OTR) is estimated by the foUowiag standard procedure (12), where the rate of mass transfer per unit volume of Hquid is taken to be directly proportional to the driving force of the system... 

The SORT value when divided by the standard conditions oxygen transfer rate (OTR) given for a mechanical aerator yields the oxygen concentration required for treatment. 

The oxygen transfer rate (OTR), or the rate at which oxygen is transferred from the gas to the liquid phase, must be a least equal to the peak oxygen load (OUR) at steady state, and can be determined from Equation 11-40 ... 

Oxygen transfer rate (OTR) The product of volumetric oxygen transfer rate kj a and the oxygen concentration driving force (C - Cl), (ML T ), where Tl is the mass transfer coefficient based on liquid phase resistance to mass transfer (LT ), a is the air bubble surface area per unit volume (L ), and C and Cl are oxygen solubility and dissolved oxygen concentration, respectively. All the terms of OTR refer to the time average values of a dynamic situation. 

Foam in the bioreactor is troublesome it can reduce the oxygen transfer rate (OTR). Antifoam is use to prevent foam formation. However, excess antifoam may cause growth inhibition in the course of fermentation. The simplest device is known as a foam breaker, which is mounted on the stirrer shaft located on the surface of liquid. It is a flat blade. 

If you aerate a bioreactor, power consumption is much less than a non-aerated bioreactor. Oxygen transfer rate, OTR 6 X 10 3 kgm-3 Oxygen uptake rate, OUR 0.65 mmol 02 kg 1 cell Specific growth rate, umax 0.5 h 1... 

Calculate mass transfer coefficient in a 60 m3 fermenter with a gas and liquid interfacial area of a = 0.3 m2-m 3, given pbroth = 1200kg m-3. The small reactor has working volume of 0.18m3, 1 vvm aeration rate. Oxygen transfer rate (OTR) is 0.25kmol in 3 h 3. There are two sets of impellers, and flat-blade turbine types of impeller were used, HL= 1.2/),. Find the exact specifications of a large fermenter. 

The key components for process monitoring were selected according to these data and some additional information. The in situ monitoring of the DO as well as the oxygen and carbon dioxide concentrations in the off gas allowed the evaluation of the oxygen transfer rate (OTR), the C02 production rate (CPR) and the respiratory quotient (RQ). The control of the pH-value and the DO was the prerequisite for the maintenance of the optimal growth and product formation conditions. 

This property allows us to monitor some parameters such as metabolizable sugars. Obviously, the parameter closely correlates with the oxygen transfer rate (OTR Fig. 6). Sugars are metabolized with consumption of oxygen. Thus, the OTR increases with decreasing sugar concentrations. 

The field oxygen transfer rate (OTR) in wastewater can be estimated from the SOTR by applying the... 

Gas-liquid mass transfer is commonly modeled in terms of a gas film (between the bulk gas and interface) and a liquid film (between the interface and bulk liquid). Hindrance to mass transfer causes soluble gas (e.g., O2) concentrations to decrease across these films. The highest mass transfer resistance usually exists in the liquid film therefore, it controls the overall oxygen transfer rate (OTR). In aerobic fermentation, an effective fermenter design achieves an efficient OTR through intimate gas-liquid contact. OTR is described in terms of oxygen concentration and characteristics of the gas-liquid interface, as follows ... 

The DO concentration in the liquid is monitored with a DO probe and recorded after it reaches a steady-state (i.e., constant) value. The oxygen generation rate (OGR) in the liquid equals the oxygen transfer rate (OTR), and is related to the hydrogen peroxide mass feed rate (QhjOj) as shown in Eq. (4)... 

Oxygen transfer rate (OTR) was determined using the sodium sulfite oxidation method [12]. OTRs were measured for standard Erlenmeyer flasks of 500-mL flask, 200-mL flask, 100-mL flask, 100-mL serum flask, and 100-mL serum flask filled with nitrogen, containing 100 mL of medium, respectively, shaken at 150 rpm at 37 °C. The OTRs of different oxygen-limited conditions were 12.6, 8.4, 5.1, 3.3, and 0 mmol/L h, respectively. 

Figure 3. Strategies for optimization of continuous culture for production of single-cell protein. Top, under continuous culture isotherm with a fixed value for carbon source feed concentration. D is the dilution rate of maximum productivity. Bottom, comparison of isotherm for fixed substrate feed concentration. So, with that for fixed oxygen transfer rate, OTR (curves show the maximum cell concentration for a given OTR and cell yield).

Fig. 2 c, d c specific gas/liquid interfacial area, and d oxygen transfer rate (OTR) and volumetric mass transfer coefficient ki a of oxygen... 

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