초록
<P><B>Abstract</B></P> <P>A bioreactor for the production of hydrogen from the dark fermentation of organics is studied by a comprehensive modelling strategy. The bioreactor is a dual impeller vortex ingesting stirred tank working under batch and attached-growth conditions. Two geometrical configurations of the reactor are investigated: one devised to ensure an effective fluid dynamics behaviour and the other proposed to increase the hydrogen productivity. The turbulent gas–liquid fluid dynamics, the production and the recovery of <I>H</I> <SUB>2</SUB> from the liquid phase are predicted by the numerical solution of the two-phase Reynolds averaged Navier–Stokes equations and the species mass transport equations, including a simplified kinetic model for the fermentative hydrogen production found in literature and a local interphase mass transfer model for the hydrogen stripping from the aqueous to the gas phase. A simplified model for the description of the interfacial area in the context of the two-fluid model is also proposed. This work suggests a method for the predictive simulations of a complex biological process via numerical modelling based on Computational Fluid Dynamics. The main outcome of the proposed investigation method is a detailed estimation of the different relevant variables and their interaction on a local basis, providing a viable tool for the optimization and the scale-up of bioreactors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A comprehensive model for the dark fermentation in a bioreactor is proposed. </LI> <LI> Fluid dynamics, bioreaction and interphase mass transfer rates are modelled locally. </LI> <LI> A newly proposed interfacial area formulation for the two-fluid model is adopted. </LI> <LI> CFD allows local and instantaneous analysis of the phenomena inside the reactor. </LI> <LI> Two different bioreactor configurations were study and evaluated by means of CFD. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>