Positioning a Measurement System for Determining the Mixing Quality in Biogas Digesters

Abstract

AbstractMixing quality in agricultural biogas plants is crucial for nutrition supply to the microorganisms and needs to be ensured by an energy‐efficient mixing strategy. Various approaches have been proposed to determine the mixing quality in biogas digesters. Among them are magnetic‐inductive or force sensors brought into vertical digesters through the concrete wall. This article presents an approach to locating these sensors effectively around the circumference of the digester to avoid positioning in dead zones and maximize information quality regarding flow and mixing behavior. Particle image velocimetry is used to measure flow fields in a transparent model digester. Finally, optimum measurement locations considering three widely used agitator geometries are suggested.