Oxygen Transfer Characteristics of an Ejector Aeration System

Yang, Hee‐Man; Park, Sang-Kyoo

doi:10.5293/ijfms.2012.5.1.010

Cited by 4 publications

(2 citation statements)

References 20 publications

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“…The limitations on oxygen mass transfer rate in the cathode space and the low oxygen concentration in marine water impose big problems on the fuel cell performance. It is well known that the Venturi tube ejectors enable high mass transfer rates and good water saturation with gases at very low energy demand [17]. It can be used for feeding the cathode space saturated by oxygen solution.…”

Section: Introductionmentioning

confidence: 99%

Performance of Sulfide-Driven Fuel Cell Aerated by Venturi Tube Ejector

et al. 2021

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Hydrogen sulfide is frequently met in natural waters, like mineral springs, but mostly it is found in marine water with low renewal rate. The Black Sea has extremely high hydrogen sulfide content. It can be utilized in different ways, but the most promising one is direct conversion into electricity. This result can be attained by a sulfide-driven fuel cell (SDFC), converting sulfide to sulfate thus releasing electric energy up to 24 GJ/t. One of the most important problems is the mass transfer limitation on oxygen transfer in the cathode space of the fuel cell. This problem can be solved using a gas diffusion electrode or highly efficient saturation by oxygen in an ejector of the Venturi tube type. This work presents experimental data in laboratory-scale SDFC for sulfide conversion into sulfate, sulfite and polysulfide releasing different amounts of electric energy. Two types of aeration are tested: direct air blow and Venturi-tube ejector. Besides pure graphite, two catalysts, i.e., cobalt spinel and zirconia-doped graphite were tested as anodes. Experiments were carried out at initial sulfide concentrations from 50 to 300 mg/L. Sulfate, sulfite and thiosulfate ions were detected in the outlet solutions from the fuel cell. The electrochemical results show good agreement with the chemical analyses. Most of the results show attained high efficiencies of the fuel cell, i.e. up to 80%. The practical applications of this method can be extended for other purposes, like treatment of polluted water together with utilization as energy.

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Section: Introductionmentioning

confidence: 99%

Performance of Sulfide-Driven Fuel Cell Aerated by Venturi Tube Ejector

et al. 2021

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“…By overcoming mass transfer limitations, significantly higher space time yields can be achieved . Beside the application in the chemical industry, JLRs are frequently used for the biocatalytic treatment in wastewater applications and due to their high mass transfer performance, JLRs can be operated at high biomass concentrations .…”

Section: Introductionmentioning

confidence: 99%

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

Weber

Schaepe

Freyer

et al. 2018

Engineering in Life Sciences

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In industrial biotechnology increasing reactor volumes have the potential to reduce production costs. Whenever the achievable space time yield is determined by the mass transfer performance of the reactor, energy efficiency plays an important role to meet the requirements regarding low investment and operating costs. Based on theoretical calculations, compared to bubble column, airlift reactor, and aerated stirred tank, the jet loop reactor shows the potential for an enhanced energetic efficiency at high mass transfer rates. Interestingly, its technical application in standard biotechnological production processes has not yet been realized. Compared to a stirred tank reactor powered by Rushton turbines, maximum oxygen transfer rates about 200% higher were achieved in a jet loop reactor at identical power input in a fed batch fermentation process. Moreover, a model‐based analysis of yield coefficients and growth kinetics showed that E. coli can be cultivated in jet loop reactors without significant differences in biomass growth. Based on an aerobic fermentation process, the assessment of energetic oxygen transfer efficiency [kgO2 kW−1 h−1] for a jet loop reactor yielded an improvement of almost 100%. The jet loop reactor could be operated at mass transfer rates 67% higher compared to a stirred tank. Thus, an increase of 40% in maximum space time yield [kg m−3 h−1] could be observed.

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An artificial neural network model for predicting volumetric mass transfer coefficient in the biological aeration unit

Muloiwa,

Dinka,

Nyende‐Byakika

2024

Water & Environment J

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The solubility of oxygen in a liquid is limited/restricted by the gas–liquid film that prevents gas from dissolving in wastewater. Oxygen in the biological aeration unit (BAU) is required by microorganisms to survive and eliminate organic and inorganic matter. This study developed a volumetric mass transfer coefficient (KLa) model using Artificial Neural Network (ANN) algorithm. The performance of the KLa model was evaluated using coefficient of determination (R2), mean squared error (MSE), and root mean squared error (RMSE). KLa model produced R2 (0.852), MSE (0.0006), and RMSE (0.0245) during the testing phase. Biomass concentration (22.29%), aeration period (20.55%), and temperature (19.63%) contributed the highest towards the KLa model. KLa model showed that the BAU should be operated at high temperatures (35°C), low biomass concentration (1.65 g/L), and low aeration period (1 h) instead of high airflow (30 L/min). Temperature should be included in the modelling of the BAU, to achieve optimum KLa.

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Oxygen Transfer Characteristics of an Ejector Aeration System

Cited by 4 publications

References 20 publications

Performance of Sulfide-Driven Fuel Cell Aerated by Venturi Tube Ejector

Performance of Sulfide-Driven Fuel Cell Aerated by Venturi Tube Ejector

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

An artificial neural network model for predicting volumetric mass transfer coefficient in the biological aeration unit

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