Data/hora: 13/06/2024 18:22:49

Provedor de dados: | 5
País: | France
Título: | Conception et étude d'un photobioréacteur pour la production en continu de microalgues en écloseries aquacoles
Autores: | Olivo, Erell.
Data: | 2007-09-21
Ano: | 2007
Palavras-chave: | Hatchery; Isochrysis affinis galbana microalgae swirl flow airlift continuous culture photobioreactor aquaculture écloserie; Isochrysis affinis galbana microalgues tourbillonnaire airlift culture continue photobioréacteur aquaculture.
Resumo: | This thesis describes the conception and the study of a photobioreactor dedicated to aquaculture. The state of the art and the technico-economic constraints proper to this activity led to the choices to a simple reactor, volume variable, cheap to produce and reliable for continuous cultures. The elementary module is made of two vertical columns, connected by flanges. An airlift injection located at the base of the column (airlift reactor) generates a swirling flow circulation in order to minimize the biofilm development on the inner side of the column. A pilot of 6.1 liters has been conceived to study the radiative transfers, the hydrodynamics and the biological cultures in continuous mode. Coupling a radiative transfer model (two flux model) with the light-growth curve (response) of the aquacultural microalgae Isochrysis affinis galbana, allowed the prediction of the photobioreactor productivity for different experimental conditions (incident flux, dilution rate, column diameter). A compromise between productivity and costs has been obtained with a 60 mm diameter column.  Hydrodynamics studies realized via conductimetric method and particle imagery velocimetry technique (PIV) have given access to radial profiles of the axial and tangential velocity components, flow velocity and swirl intensity. Different air flow rates, air injection types and flange's velocity factors (FV) have been tested. The swirl attenuation of the swirl motion (after one meter from the injection) has been displayed prominently. To complete, aeration performance of the reactor has been determined experimentally (volumetric gaz-liquid mass transfer coefficient) and confirmed the capacity of the photobioreactor to evacuate the oxygen produced by photosynthesis. Finally, the biologic studies ran under continuous cultures revealed that the productivity reached inside the photobioreactor was similar whatever the flow type, swirl flow (FV4) or axial flow (FV1). Productivity of 1.5.1010 ± 0.2.1010 cell.l-1.d-1 (for a surface irradiation of 260 ± 20 µmol.m-2.s-1 and a dilution rate of 0.36 ± 0.01 d-1) shows that it can cover quantitatively the larval nutritive needs in commercial hatcheries estimated at 1.15.1012 cell.d-1. The swirl motion benefit lies into limitating the biofouling on the reactor wall and thus can ensure the production of the pilot on the long term. This study has allowed the principal features of the prototype design to be chosen (18 elementary modules, 120 liters). This novel study project, specifically dedicated to mollusk hatcheries gave them opportunity to run microalgae continuous cultures.
Tipo: | Text
Idioma: | Francês
Identificador: | http://archimer.ifremer.fr/doc/2008/these-3847.pdf
Editor: | Université de Nantes
Relação: | http://archimer.ifremer.fr/doc/00000/3847/
Formato: | application/pdf