Predicting molar composition of biogas by reaction kinetics and temperature dependence on anaerobic digestion

Abstract

Mathematical model was developed and simulated to predict the molar composition of biogas produced by anaero-bic digestion. Several models have been developed for anaerobic processes with reduced number of parameters, but requiring data resolution, thus posing problem of data precision. The prediction model was based on reaction kinetics of anaerobic digestion, while Ratkowsky's formulation was used to examine the dependence of temperatu-re on methanogenic process. The reaction kinetics model was simulated using SciLab coding of fourth order Ru-nge Kutta numerical algorithm. Comparison of numerical experimentation results with published experimental data gave satisfactory agreement. The cumulative volume of methane was predicted in the temperature range of 20 - 40 °C, and the maximum volume of methane generated was 26.39 L at 35 °C for mesophilic bacteria.

Keywords: Anaerobic Digestion, Hydrolysis, Acidogenesis, Acetogenesis, Methanogenesis, Mesophilic Bacteria