Biogas system fault detection and control

Critical aspects that are lacking in present digester operation are that of fault detection and control. Too high or too low a biogas pressure, methane gas leak, oxygen ingress into the digester and varying slurry levels are all potential contributors of catastrophe, to the installation and to the user. In this paper an integrated fault detection and control strategy based both on fuzzy logic algorithm of internal digesters' operating conditions and external leak detection is developed. The fuzzy logic algorithm being fed by pressure and slurry level inputs seeks to establish the internal danger level of the digester at any particular instant with the view of taking corrective action, whilst any methane and oxygen leaks are to be immediately halted. The fault detection and control strategy is implemented in the PIC18F4550-I/P microcontroller.