Analysis of carbon footprint and energy performance of biohydrogen production through gasification of different waste agricultural biomass from the Philippines

Agricultural crop residues are available in abundance in Asian countries such as the Philippines. These residues have high potential as feedstock to produce clean and high-value energy products, to mitigate global warming and reduce dependence on fossil fuels. This study investigated the carbon footprint and energy performance of biohydrogen production system through gasification of different waste agricultural biomass. The proposed system includes biomass transport and pre-processing, gasification process, and biohydrogen enrichment and purification technologies. Calculation of the syngas composition was performed using a stoichiometric-thermodynamic equilibrium model using python script. Generation of energy from fossil fuel to support the system operations produced the highest greenhouse gas emission. The production system using sugarcane leaves as feedstocks exhibited the lowest carbon footprint, highest gasification efficiency, and best energy performance based on the computed energy ratio. Biophysical allocation was used to determine the burden associated with the biomass during its growth phase. Incorporation of the carbon uptake during biomass growth phase reduced the carbon footprint of the system. Sensitivity analysis showed that increasing C/O and H/O ratio improves the quality of the syngas produced, while increasing C/H ratio results to lower biohydrogen yield. In selection of feedstock mix, it is preferred to maximize C/O and H/O ratio while reducing C/H ratio of the feedstock composition.