Adaptive multivariable pH regulation of a biogas tower reactor (Q1267255)

An adaptive multivariable controller for an anaerobic treatment of waste water in a new type of tower reactors is introduced. The control objective is to keep the conversion rates of organic compounds into methane and carbon dioxide constant by regulating the pH values. A nonlinear high-order model of the conversion process is reduced to an interconnected system of four one-dimensional models. The pH value in the coupled module is kept within a pre-specified region by a proposed nonlinear state-feedback law and a gain adaptation strategy. The controllers are tested on an industrial pilot reactor. It is shown by experiments that the control system tolerates large disturbances and is robust against changing parameters.