Scale-up of photo-bioreactors for microalgae cultivation by π-theorem

Paladino, Ombretta; Neviani, Matteo

doi:10.1016/j.bej.2019.107398

Cited by 24 publications

(7 citation statements)

References 42 publications

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“…Four external loop airlift reactors (EL-ALRs) were designed and assembled to conduct an experimental campaign principally apt to gauge the main dynamic parameters [8] and to conduct a rigorous scale-up procedure [13] of the cultivation process. A sketch of one of the EL-ALRs, annotated with the main dimensions, is illustrated in Figure 1.…”

Section: Experimental Reactor and Measurementsmentioning

confidence: 99%

“…The corresponding 𝑘 𝐿 is comprised between 0.01 and 0.04. The values of 𝑘 𝐿 related to the bubble regime and the fully developed churn regime also tested during this campaign, can be found in [13]. The optimal Sh number, calculated for the conditions reported in Table 5, and chosen for the outdoor cultivation tests, is in the range 1400 -1800.…”

Section: Evaluation Of Gas-liquid Mass Transport Coefficientsmentioning

confidence: 99%

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Gas bubble dynamics in airlift photo-bioreactors for microalgae cultivation by level set methods

Neviani

Bagnerini

Paladino

2021

Fuel

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Section: Experimental Reactor and Measurementsmentioning

confidence: 99%

Section: Evaluation Of Gas-liquid Mass Transport Coefficientsmentioning

confidence: 99%

Gas bubble dynamics in airlift photo-bioreactors for microalgae cultivation by level set methods

Neviani

Bagnerini

Paladino

2021

Fuel

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“…A similar conclusion was developed by [30] in the scaling of photobioreactors for the cultivation of microalgae, in which, using Buckingham's π theorem, the authors managed to develop a mathematical model of similarity between the laboratory and pilot scales. In this study, the dimensionless parameters were related directly to the agitation speed and the aeration flow through Equation ( 5), previously presented.…”

Section: Bioprocess Scale-upmentioning

confidence: 74%

“…In this way, a physical law can be reformulated that interconnects some physical quantities as a function of dimensionless numbers. The objective of the Pi theorem is to define significant non-dimensional parameters, which can be representative of the problem considered and can be used to scale the variables involved on specific physical assumptions [30,31].…”

Section: Dimensional Analysis Using the Buckingham Pi Theoremmentioning

confidence: 99%

Mathematical Model for Scaling up Bioprocesses Using Experiment Design Combined with Buckingham Pi Theorem

et al. 2021

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Scaling up bioprocesses from the experimental to the pilot or industrial scale involves heuristics and scale relationships that are far from the specific phenomena and are usually not connected to the experimental data. In complex systems, the scaling-up methodology must connect the experimental data with the tools of engineering design. In this work, a two-stage gold bioleaching process was used as a case study to develop a mathematical model of bioprocess scaling that combines the design of experiments with dimensional analysis using the Buckingham Pi theorem to formulate a predictive model that allows scaling up bioprocesses. It was found that the C/N, C/K, and T/C ratios are dimensionless factors that can explain the behavior of a system. Using the Pearson Product–Moment bivariate analysis, it was found that the dimensionless factors C/N and C/K were correlated with the leaching potential of the fermented broth at 1060 cm−1. With these results, a non-linear logarithmic model based on dimensionless parameters was proposed to explain the behavior of the system with a correlation coefficient of R2 = 0.9889, showing that the optimal conditions to produce fermented broth comprised a C/N ratio close to 50 and a C/K ratio close to 800, which allows predicting the scaling of the bioprocess.

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“…The microalgae concentration was offline daily acquired by measuring the absorbance of samples at different wavelengths (430, 480, 650, and 680 nm). Details about calibration curves can be found in [35]. A Hach DR-6000 UV-VIS spectrophotometer was used, while the wastewater composition was measured by both GC and UV-VIS spectrophotometers.…”

Section: Wastewater Recycling In Microalgae Cultivationmentioning

confidence: 99%

Sustainable Biodiesel Production by Transesterification of Waste Cooking Oil and Recycling of Wastewater Rich in Glycerol as a Feed to Microalgae

Paladino

Neviani

2021

Sustainability

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The amount of solid and liquid organic waste and wastewater is continuously increasing all over the world. The necessity of their reuse and recycling is, therefore, becoming more and more pressing. Furthermore, the limited fossil fuel resources, in conjunction with the need to reduce greenhouse gas emissions, advocate the production of renewable fuels. In this work, we analyze a sustainable second-generation process to produce biodiesel by transesterification of waste cooking oil, coupled with a third-generation process in cascade for recycling the incoming wastewater. Since this latter is rich in glycerol, it is used as a feed for microalgae, from which oil can be extracted and added to the waste cooking oil to further produce biodiesel and close the cycle. We studied the influence of different factors like temperature, catalyst load, and reactants ratio on the kinetics of transesterification of the waste oil and estimated the kinetic parameters by different kinetic schemes. The obtained values of activation energies and pre-exponential factors at chosen conditions of T = 60 °C and catalyst load of 0.6% w/w in methanol are: Ea,direct = 35,661 J mol−1, Ea,reverse = 72,989 J mol−1, k0,direct = 9.7708 [dm3 mol−1]3 min−1, and k0,reverse = 24,810 [dm3 mol−1]3 min−1 for the global fourth-order reversible reaction scheme and Ea = 67,348 J mol−1 and k0 = 2.157 × 109 min−1 for the simplified pseudo-first-order irreversible reaction scheme; both in strong agreement with literature data. Furthermore, we designed very efficient conditions for discontinuous and continuous operating mode, both at lab-scale and pilot-scale. The quality of the biodiesel produced from waste cooking sunflower oil is compared with that of biodiesel produced by different kinds of virgin vegetable oils, showing that the former possesses acceptable quality standards (Cetane number = 48 and LHV = 36,600 kJ kg−1). Finally, the recycling of wastewater rich in glycerol as a nutrient for mixotrophic microalgae nurturing is discussed, and microalgae growing kinetics are evaluated (k1 about 0.5 day−1), endorsing the possibility of algae extraction each 4–5 days in a semi-continuous operating mode. The experimental results at the pilot scale finally confirm the quality of biodiesel, and the obtained yields for a two-stage process prove the competitiveness of this sustainable process on the global market.

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Scale-up of photo-bioreactors for microalgae cultivation by π-theorem

Cited by 24 publications

References 42 publications

Gas bubble dynamics in airlift photo-bioreactors for microalgae cultivation by level set methods

Gas bubble dynamics in airlift photo-bioreactors for microalgae cultivation by level set methods

Mathematical Model for Scaling up Bioprocesses Using Experiment Design Combined with Buckingham Pi Theorem

Sustainable Biodiesel Production by Transesterification of Waste Cooking Oil and Recycling of Wastewater Rich in Glycerol as a Feed to Microalgae

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