title: Material and energy balances of an integrated biological hydrogen production and purification system and their implications for its potential to reduce greenhouse gas emissions.
abstract: The materials and energy in an integrated biological hydrogen production and purification system involving hydrolysis, dark fermentation, photo fermentation, CO2 fixation and anaerobic digestion are balanced by integrating the results from multiple experiments, simulations and the literature. The findings are two fold. First, using 1000 kg rice straw as a substrate, 19.8 kg H2 and 138.0 kg CH4 are obtained. The net energy balance (NEB) and net energy ratio (NER) are -738.4 kWh and 77.8%, respectively, both of which imply an unfavorable energy production system. Opportunities to improve the performance particularly lie in the photo fermentation process. Second, greenhouse gas emissions are evaluated for various options. The results were comparable with the emission inventory of electricity generated from fossil fuels. NEB and NER under a zero-carbon-emission constraint were discussed in detail to clarify completely the implications of the energy and material balances on greenhouse gas emissions.
authors.affiliation: Department of Environmental Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan. fuku@mail.ncku.edu.tw
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Fukushima
authors.forename: Yu-Jung
authors.initials: YJ
authors.lastname: Huang
authors.forename: Jhen-Wei
authors.initials: JW
authors.lastname: Chen
authors.forename: Hung-Chun
authors.initials: HC
authors.lastname: Lin
authors.forename: Liang-Ming
authors.initials: LM
authors.lastname: Whang
authors.forename: Hsin
authors.initials: H
authors.lastname: Chu
authors.forename: Young-Chong
authors.initials: YC
authors.lastname: Lo
authors.forename: Jo-Shu
authors.initials: JS
authors.lastname: Chang
mesh_terms: D056804:Biofuels / Q000032:analysis*; D001709:Biotechnology / Q000379:methods*; D005740:Gases / Q000032:analysis*; D017752:Greenhouse Effect / Q000517:prevention & control*; D006859:Hydrogen / Q000302:isolation & purification* / Q000378:metabolism*; D012275:Oryza / Q000378:metabolism; D013816:Thermodynamics; D014866:Waste Products / Q000032:analysis
chemical_list: D056804:Biofuels; D005740:Gases; D014866:Waste Products; D006859:Hydrogen