Vertical biogas reactor V=8287 m3 (D23,05mxH19,87m) is a tank made of enameled steel panels (sheets) and assemled on bolts. The central agitator is attached to the ceiling. The upper rings of panels at the level of liquid-gas and the ceiling are made of stainless steel. The reactor is installed on a concrete foundation with a sealant. The substrate is heated in an external heat exchanger. The vertical orientation of the fermenter provides a better heat and mass transfer than a low and wide fermenter. Such reactors are used in large biogas plants for the food industries (sugar mills, ethanol distilleries, vegetable processing).