Exergy analysis and optimization of bio-methane production from corn stalk pretreated by compound bacteria based on...

An exergy equilibrium model was established to obtain the exergy efficiency under different conditions of compound bacteria pretreatment and anaerobic digestion (AD) of corn stalk. The Genetic Algorithm (GA) was applied to optimize the exergy efficiency of the combination process of the pretreatment and AD. The maximum exergy efficiency with the GA was 19.04%, corresponding to the optimal pretreatment parameters: pretreatment temperature 33.34℃, stalk particle size 0.50 mm, ventilation rate 0.88 L/min, pretreatment time 169.03 h. The optimal AD parameters were: digestion temperature 38.08℃ and stirring rate 48.04 r/min. The validation experiment exergy efficiency reached to 19.25%, which was 24.37% higher as compared to that of the non-pretreatment process. Under these optimal conditions, the energy consumption of the compound bacteria pretreatment and the time of the bio-methane production process were effectively reduced.