Hydrogen production from biomass via gasification process: The results of the eu UnifHY project

This paper quotes an overview of the UNIfHY project results regarding pure hydrogen production from biomass gasification. Tests with different gasification agents (steam/air/oxygen) and at different temperatures showed syngas yield from 1.1 to 1.7 Nm3dry/kg of dry biomass, hydrogen content from 20 to 40%-v dry, tars, particulate in the range of 10-20 g/Nm3dry, sulphur and chlorine compounds in the range of 50-90 ppmv, ammonia up to 1600 ppmv. Candle filters showed particulate removal efficiency higher than 99%-wt. A portable purification system (PPS) consisting in a ZnO guard bed reactor, a water gas shift reactor (WGS), compressor and gas upgrading unit (PSA) was designed and realized. The system was proven to be operable stably and continuously in experimental runs lasting more than 12 h. Hydrogen production at concentration of 99.99%-v was achieved with an H2 yield from PSA of 66.4%. Based on the data collected, UNIfHY can reach an economic production cost of 3-10 €/kg H2 (in the range 4.00-0.04 t H2/day, respectively) with low environmental impact (0.5-2.4 kg CO2/kg H2) but targets have to be different for decentralised (40% efficiency, 10 years lifetime, <10 €/kg cost, production of electricity and heat) and centralised (70%, 20 years, <5 €/kg no electricity neither heat) production and higher performance and reliability can be achieved by means of the implementation of better configurations.