Hydrogen production from biomass is one of eco-friendly system design that can reduce carbon dioxide emissions at the production, due to a character of carbon neutral. In the hydrogen recovery process of the Blue Tower process, PSA (Pressure Swing Adsorption) is adopted, but its auxiliary power occupies about 60% for the whole energy consumption. That is, even if non-fossil fuel is used as a raw material, there is concern that the environmental contribution would be reduced. Thus, the 2-step PSA which achieves both carbon dioxide adsorption and hydrogen purification efficiently was developed. In this paper, using the experimental data, the performance simulation model was built to analyze the specification of Bio-H<sub>2</sub> production system. Also, the exergy efficiency and carbon dioxide emissions were estimated. As a result, the Bio-H<sub>2</sub> production system with 2-step PSA improved the exergy efficiency by about 1% compared with the conventional PSA model, and it was found that the negative emission effect might be achieved.
