Multi-objective optimization of methane production system from biomass through anaerobic digestion

This work addressed the multi-objective optimization of a biogas production system considering both environmental and economic criteria. A mixed integer non-linear programming (MINLP) model was established and solved with non-dominated sorting genetic algorithm II, from which the Pareto fronts, the optimal technology combinations and operation conditions were obtained and analyzed.

It's found that the system is feasible in both environmental and economic considerations after optimization. The most expensive processing section is decarbonization; the most expensive equipment is anaerobic digester; the most power-consuming processing section is digestion, followed by decarbonization and waste management.

The positive green degree value on the process is attributed to processing section of digestion and waste management. 3:1 chicken feces and corn straw, solar energy, pressure swing adsorption and 3:1 chicken feces and rice straw, solar energy, pressure swing adsorption are turned out to be two robust technology combinations under different prices of methane and electricity by sensitivity analysis.

The optimization results provide support for optimal design and operation of biogas production system considering environmental and economic objectives.