Impact of shear stress and impeller design on the production of biogas in anaerobic digesters.

Fiche publication

Date publication

décembre 2017

Journal

Bioresource technology

Auteurs

Membres identifiés du Cancéropôle Est :
Pr OLMOS Eric

Tous les auteurs :
Lebranchu A, Delaunay S, Marchal P, Blanchard F, Pacaud S, Fick M, Olmos E

Lien Pubmed

https://www.ncbi.nlm.nih.gov/pubmed/28863993

Résumé

Today, intensification of anaerobic digestion is still a scientific and technical challenge. The present study proposed combined experimental and computational fluid dynamics simulations to characterize the impact of shear stress and impeller design on the biogas production after sequential additions of substrate. Liquid phase (cattle manure digestate) rheological law was experimentally determined and input in numerical simulations. The results showed that the original use of a double helical ribbon in digester allowed a significantly faster dispersion of fresh substrate than the use of a classical Rushton turbine, leading to a 50% higher methane production rate. However, with both impellers, too high agitation rates entailed a clear slow-down of production rate and a decrease in CH content. To avoid this loss of productivity, it was shown that the maximal value of shear stress, determined by numerical simulations, was a consistent parameter to set the upper agitation conditions in digesters.