Aerobic bioreactors: A Bayesian point of view applied to hydrodynamic characterization and experimental evaluation of tracers

Abstract

This work describes the hydrodynamic diagnosis of an aerobic fixed-bed reactor, obtained by estimating parameters via the Markov chain Monte Carlo (MCMC) method. Five hydrodynamic models are evaluated. Of these models, four were classical (large dispersion, small dispersion, N-CSTR in series and plug flow with mass exchange), while the fifth is a proposal for the characterization of the short-circuit anomaly, the N-CSTR in parallel model. Due to the three-phase peculiarities of the reactor involving adsorption and dispersion phenomena, three tracers were evaluated through the stimulus–response test: eosin Y, bromophenol blue and bromocresol green. Green bromocresol is the most appropriate tracer for this type of analysis, with the hydrodynamic characterization showing that the reactor is mainly influenced by short-circuit anomaly. Parameter estimation obtained via MCMC, together with the model selection carried out by Bayesian criteria, pointed at the proposed model, n-CSTR in Parallel, as the best fit to the experimental data.