scholarly journals Mass Transfer Features of Wavy-Bottomed Cascade Photobioreactors

2021 ◽  
Vol 5 (4) ◽  
pp. 86
Author(s):  
Monica Moroni ◽  
Giorgia Sed ◽  
Agnese Cicci ◽  
Barbara Mazzarotta ◽  
Nicola Verdone ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Energy Efficient ◽  
Scale Up ◽  
Biomass Concentration ◽  
Efficient Production ◽  
Light Path ◽  
High Biomass ◽  
Growth Limitation ◽  
Microalgae Biomass ◽  
High Biomass Concentration

It has been suggested that the energy-efficient production of microalgae biomass can be more easily obtained in short light path photobioreactors that can be operated at high biomass concentration. On the downside, however, high biomass concentrations also require an efficient gas exchange rate to avoid metabolic growth limitation or inhibition. A cascade photobioreactor featuring a thin liquid layer flowing down a sloping, wavy-bottomed surface can be operated at a biomass concentration that is much higher compared to most usual open-type equipment. Liquid flow, upon investigation, proved to exhibit peculiar “local recirculation” hydrodynamics, potentially conducive to the mixing of superficial and deep zones of the photobioreactor. Mass transfer coefficient represents a useful parameter to optimize the performance of a microalgal photobioreactor and its scale-up. The aim of the present article is to discuss the experimental mass transfer features of this novel type of photobioreactor and highlight expected opportunities and issues entailed by different ways of installing and operating such novel types of photobioreactors.

Multi-inhibition kinetic model for the growth ofAlcaligenes eutrophus

1995 ◽  
Vol 41 (13) ◽  
pp. 249-256 ◽  
Author(s):  
Lamia Belfares ◽  
Michel Perrier ◽  
Bruce A. Ramsay ◽  
Juliana A. Ramsay ◽  
Mario Jolicoeur ◽  
...  
Keyword(s):  
Specific Growth ◽  
Biomass Concentration ◽  
Optimization Method ◽  
Model Parameters ◽  
High Biomass ◽  
Ammonium Ions ◽  
Model Predictions ◽  
Inhibition Kinetic ◽  
High Biomass Concentration ◽  
Classical Optimization

During the growth phase of Alcaligenes eutrophus, it was observed that the concentrations of glucose and ammonium ions are inhibitory at a certain level, which affects the specific growth rate. Moreover, it has been established from previous work that (an) unidentified substance(s) inhibit(s) the growth at biomass concentrations above 10 g∙L−1. A model taking into account these multiple inhibitory factors is proposed to predict the growth of A. eutrophus. The model parameters were determined by batch experiments except for the parameter associated with inhibition at high biomass concentration. This parameter was estimated by a classical optimization method. The validity of the model was tested by comparing the model predictions with experimental data obtained in batch and transient continuous fermentations and with literature data.Key words: A. eutrophus, inhibitory product, high biomass concentration.

Investigation of the Effect of Growth From Low to High Biomass Concentration Inside a Photobioreactor on Hydrodynamic Properties of Scenedesmus obliquus

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Evan Le ◽  
Chanwoo Park ◽  
Sage Hiibel
Keyword(s):  
Production Efficiency ◽  
Scenedesmus Obliquus ◽  
Biomass Concentration ◽  
High Energy ◽  
Biodiesel Production ◽  
Algal Culture ◽  
High Biomass ◽  
Algae Biodiesel ◽  
The Impact ◽  
High Biomass Concentration

Most of the current production cost in algae biodiesel plants utilizing photobioreactors comes from the high energy required for pumping, CO2 transfer, mixing, and harvesting. Since pumping affects the mixing and CO2 transfer, which are the main factors in algae productivities, solutions to reduce the required energy for pumps can significantly make algae biodiesel production more economically feasible. An investigation on the effect of Scenedesmus obliquus’s growth from low to high biomass concentration inside a horizontal tubular photobioreactor to determine the impact that it has on hydrodynamic performances, which will affect cost and production efficiency, was performed. As the biomass concentration increased, the algal culture was found to remain Newtonian. Additionally, the biomass concentration (expressed in cell density) was found to have lower viscosity even at the highest concentrations evaluated at 2.48 × 108 cell/ml (1.372 × 10−3 ± 1.32 × 10−4 Pa s) compared to the Modified Bold’s 3N medium (1.408 × 10−3 ± 9.41 × 10−5 Pa s). Furthermore, the total energy consumption does not appear to depend on the S. obliquus biomass concentrations, but rather on the medium the algae grows in. The rheological properties of autotrophic algae will not have significant impact on energy requirements until technology improves so that the concentrations reach those of heterotrophic algae.

The optimum medium of the suspended bio-medium aeration contactor process

1994 ◽  
Vol 29 (10-11) ◽  
pp. 183-188 ◽  
Author(s):  
C. F. Ouyang ◽  
C. M. Liaw
Keyword(s):  
Particle Size ◽  
Activated Carbon ◽  
Fluidized Bed ◽  
Shear Force ◽  
Biomass Concentration ◽  
Aeration Tank ◽  
High Biomass ◽  
The Media ◽  
Fluidized Bed Process ◽  
High Biomass Concentration

The purpose of this study is to modify the Fluidized Bed Process. Placing various particle diameters of granular activated carbon, (#20∼#30, #30∼#40, #40∼#50) as a medium in an aeration tank, in which microorganisms can attach and grow, improves the biomass concentration, volumetric loadings and removal efficiency. The continuous supply of substrates allows the thickness of bio-film on the medium to be shifted to a proper state. This is due to a friction force effect between the media and the shear force of the agitated flow. After studying the comparisons, it is concluded that the middle particle size (#30∼#40) is the best of the three particle diameters as a medium, in that it achieves a high biomass concentration, stable treatment and higher efficiency.

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