Study of the hydrodynamics and mass transfer in a rectangular air-lift bioreactor

Drandev, Stanimir; Penev, Kalin; Karamanev, Dimitre

doi:10.1016/j.ces.2016.02.041

Cited by 22 publications

(14 citation statements)

References 44 publications

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“…All these represent fundamental aspects Some observations can be made. First of all, it is interesting to note that in the diagrams in Figures 7 and 8, no plateau was observed [3,18,24,25]. This would likely suggest that the hydraulic behavior does not influence the aeration performance in a simple way.…”

Section: Discussionmentioning

confidence: 90%

“…In order to perform oxygenation tests, it was first necessary to remove all the DO present in the tap water in the tank. This was obtained by flushing such water for an appropriate time with a nitrogen stream [18]. Once the oxygen absence was confirmed, the experiments were started.…”

Section: Sampling Analysis and Data Elaborationmentioning

confidence: 99%

“…The K La was determined by considering the well-known expression dC/dt = K La (C s − C) where C is the DO at time t and C s is the DO saturation concentration at the temperature at which that oxygenation test was performed. For each air flow, the K La was determined by regression from the corresponding "oxygenation test" diagram, taking into account the temperature at which that specific test was performed [18,20] in the following way: seeing as some of the experiments were done on different days, the room temperature varied, therefore the variation of K La with the temperature was estimated to be 1.8% per 1 • C, in full agreement with that reported in the literature [22]. The K La data were then normalized at 20 • C. OC was calculated from K La using the formula [3]: OC = K La × C s × V, where V is the volume of the tank occupied by the tap water.…”

Section: Sampling Analysis and Data Elaborationmentioning

confidence: 99%

“…The purpose of the present paper was to determine the best working conditions and the corresponding best working parameters of the mini-MODUS in order to efficiently aerate anoxic water in a reasonable lapse of time without perturbing the bottom sediment at all. Three parameters were deemed to be the most important for our study [16][17][18]: the oxygen global transfer coefficient, K La ; the oxygenation capacity, OC; and the oxygenation efficiency, OE%.…”

Section: Introductionmentioning

confidence: 99%

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Preliminary Study on Mini-Modus Device Designed to Oxygenate Bottom Anoxic Waters without Perturbing Polluted Sediments

Perin

Romagnoli

Perin³

et al. 2020

Environments

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The Tangential Guanabara Bay Aeration and Recovery (TAGUBAR) project derives its origins from a Brazilian government decision to tackle the planning and management challenges related to the restoration of some degraded aquatic ecosystems such as Guanabara Bay (state of Rio de Janeiro), Vitória Bay, and Espírito Santo Bay (state of Espírito Santo). This was performed by using the successful outcomes of a previous Ministry of Foreign Affairs and Directorate General for Cooperation and Development (i.e., Direttore Generale alla Cooperazione allo Sviluppo, MFA–DGCS) cooperation program. The general objective of the program was to contribute to the economic and social development of the population living around Guanabara, Vitória, and Espírito Santo Bays, while promoting the conservation of their natural resources. This objective was supposed to be achieved by investing money to consolidate the local authorities’ ability to plan and implement a reconditioning program within a systemic management framework in severely polluted ecosystems such as Guanabara Bay, where sediments are highly contaminated. Sediments normally represent the final fate for most contaminants. Therefore, it would be highly undesirable to perturb them, if one wishes to avoid contaminant recycling. In this context, we explored a bench-scale novel technology, called the module for the decontamination of units of sediment (MODUS), which produces an oxygenated water flow directed parallel to the sediment floor that is aimed to create “tangential aeration” of the bottom water column. The purpose of this is to avoid perturbing the top sediment layer, as a flow directed toward the bottom sediment would most probably resuspend this layer. Three kinds of tests were performed to characterize a bench-scale version of MODUS (referred to as “mini-MODUS”) behavior: turbulence–sediment resuspension tests, hydrodynamic tests, and oxygenation–aeration tests. In order to understand the functioning of the mini-MODUS, we needed to eliminate as many variables as possible. Therefore, we chose a static version of the module (i.e., no speed for the mini-MODUS as well as no water current with respect to the bottom sediment and no flume setting), leaving dynamic studies for a future paper. The turbulence tests showed that the water enters and exits the mini-MODUS mouths without resuspending the sediment surface at all, even if the sediment is very soft. Water flow was only localized very close to both mouth openings. Hydrodynamic tests showed an interesting behavior. An increase of low air flows produced a sharp linear increase of the water flow. However, a plateau was quickly reached and then no further increase of water flow was observed, implying that for a certain specific geometry of the equipment and for the given experimental conditions, an increase in the air flow does not produce any reduction of the residence time within the aeration reactor. Oxygenation–aeration tests explored three parameters that were deemed to be most important for our study: the oxygen global transfer coefficient, KLa; the oxygenation capacity, OC; and the oxygenation efficiency, OE%. An air flow increase causes an increase of both KLa and OC, while OE% decreases (no plateau was observed for KLa and OC). The better air flow would be a compromise between high KLa and OC, with no disadvantageous OE%, a compromise that will be the topic of the next paper.

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Section: Discussionmentioning

confidence: 90%

Section: Sampling Analysis and Data Elaborationmentioning

confidence: 99%

Section: Sampling Analysis and Data Elaborationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Preliminary Study on Mini-Modus Device Designed to Oxygenate Bottom Anoxic Waters without Perturbing Polluted Sediments

Perin

Romagnoli

Perin³

et al. 2020

Environments

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show abstract

“…Gas–liquid multiphase reactors, which are used to improve mass transfer, are commonly used in the form of stirred reactors, bubble columns, falling film reactors, jet flow, and airlift reactors . Taylor–Couette vortex bioreactors are prime examples of reactors that use inner wall rotation to generating the pairs of toroidal vortices.…”

Section: Introductionmentioning

confidence: 99%

Gas–liquid mass transfer and bubble size distribution in a multi‐Cyclone separator

Qian

et al. 2018

AIChE Journal

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This article discusses the use of a multi-cyclone separator, which is a simplified form of a degassing hydrocyclone, in the separation of sweeping nitrogen bubbles and dissolved oxygen from water. The motion of the nitrogen bubbles and mass transfer of dissolved oxygen is discussed. It was observed that the Sauter mean diameter and gas volume in the swirling flow region as well as the total gas holdup increased as the volumetric ratio of gas to liquid flow increased. Almost all bubbles were found to exit through the gas outlet, indicating optimum performance of the bubble-separation process. The multi-cyclone separator was found to achieve good performance for the mass transfer of oxygen from water to nitrogen. This work is important in predicting the destination of bubbles and dissolved gas in swirling flow.

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Gas solid contact efficiency of pyridine synthesis reactors

et al. 2021

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The gas phase pyridine synthesis process is usually carried out in a fluidized bed reactor. The contact efficiency between the reactants and the catalysts has great influence on the reactor performance. In this paper, three fluidized bed reactors with different flow patterns were used to investigate the contact efficiency. The superficial contact efficiency index (SCEI) was defined and used in this paper to quantify the contact efficiency inside these reactors. To obtain the values of the SCEI, the ideal reactor model was constructed. The results showed that the SCEI average value decreased as the flow pattern shifted from fast fluidization to bubbling fluidization; these values were 0.86, 0.55, and 0.19 for the fast fluidized bed reactor, turbulent fluidized bed reactor, and bubbling fluidized bed reactor, respectively. An empirical correlation was proposed in this paper to predict the SCEI under different operating conditions. The model prediction results agreed well with experimental results with an average prediction error of 8%.

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Study of the hydrodynamics and mass transfer in a rectangular air-lift bioreactor

Cited by 22 publications

References 44 publications

Preliminary Study on Mini-Modus Device Designed to Oxygenate Bottom Anoxic Waters without Perturbing Polluted Sediments

Preliminary Study on Mini-Modus Device Designed to Oxygenate Bottom Anoxic Waters without Perturbing Polluted Sediments

Gas–liquid mass transfer and bubble size distribution in a multi‐Cyclone separator

Gas solid contact efficiency of pyridine synthesis reactors

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