Adaptive control of anaerobic digestion processes—a pilot‐scale application

Abstract

A simple adaptive control algorithm, for which theoretical stability and convergence properties had been previously demonstrated, has been successfully implemented on a biomethanation pilot reactor. The methane digester, operated in the CSTR mode was submitted to a shock load, and successfully computer controlled during the subsequent transitory state.

On‐line estimation of microbial specific growth‐rates: An illustrative case study

“…It is worth noting that similar ideas can be developed in other estimation cases or for control purposes (see e.g. Dochain & Bastin, 1984Renard et al, 1988). = design parameter (L/mmol-h) = design parameter (L2/mrno12*h2) = dilution rate (h-I) = discrete-time value of D(t) (h-') = yield coefficients (mmol/g) = Michaelis-Menten parameter (mmol/L) = product concentration (mmol/L) = discrete-time value of P(r) (mmol/L) = substrate concentration (mrnol/L) = substrate concentration in the influent (mmol/L) = sampling period (h) = biomass concentration (g/L) = discrete-time value of X(t) (g/L) = estimate of X(t) (in continuous-time) (g/L) = estimate of X(t) (in discrete-time) (g/L) = auxiliary variable (mmol/L)…”

Critical analysis of engineering aspects of shaken flask bioreactors

“…The CH 4 and CO 2 percentage can be measured using gas chromatographic methods or infrared measurements. The use of methane production as a process output for control is commonly employed (Renard et al, 1988(Renard et al, , 1991Ryhiner et al, 1992;Boscolo et al, 1993;Polihronakis, Petrou, and Deligiannis, 1993;Ryhiner, Heinzle, and Dunn, 1993;Chynoweth et al, 1994;Ehlinger et al, 1994;Moletta et al, 1994;Pullammanappallil et al, 1991Pullammanappallil et al, , 1992Pullammanappallil et al, , 1998. Pressure sensing is a reliable and straightforward technique for the on-line quantification of gas consumption or production in bioprocesses when only a single gas is involved (Anderlei et al, 2004).…”

“…Gas production (CH 4 and CO 2 ) is the earliest and most commonly used parameter for monitoring and control of the anaerobic process, and the use of gas flow as an online measured parameter in control systems is widespread (Renard et al, 1988(Renard et al, , 1991Boscolo et al, 1993;Ehlinger et al, 1994;Moletta et al, 1994;. Fluctuation noise in the gas flow measurements is common, and data filtering is often necessary if smooth gas measurements are needed for control purposes.…”

Feedback control design for an anaerobic digestion process

“…Despite a large research effort on nonlinear and adaptive control techniques, 5,7,8,10 the linear proportional-integral (PI) and proportional-integral-derivative (PID) controllers are dominant in the process industry and will remain so for a long time. There are many reasons for this, including their long history of proven operation, and the fact that they are well understood by many industrial operational, technical, and maintenance individuals.…”