Kinetic and thermal aspects of biogas production

An original analytical model of the biochemical behaviour of an anaerobic digester and its thermal balance under steady-state conditions is presented and described. It is based on the fundamental equations for hydrolysis, acidogenesis and methanogenesis and determined by several kinetic parameters. The thermal balance is investigated to define the optimum working temperature in relation to several operating parameters (outdoor temperature, geometry, insulation, etc.), from the maximum net energy content and the energy used to heat the fermenting system, bearing in mind the strongly temperature-dependent biogas productivity of the mesophilic bacteria.