If biomass is gasified at temperatures above 700°C, a mixture of gases and charcoal is produced. The gas produced contains mainly hydrogen, carbon monoxide, meth­ane, carbon dioxide and nitrogen. More hydrogen can be produced by a water-shift reaction where carbon monoxide is reacted with water to form carbon dioxide and hydrogen:

Biomass + heat + steam ^ H2 + CO + CO2 + CH4 (5.5)

+ hydrocarbons + charcoal

Water-shift reaction

CO + H2O = CO2 + H2 (5.6)

Using a fluidized bed gasifier with a catalyst it has been possible to obtain 60% hydrogen production. The main problem with gasification is the formation of tar, which can be minimized by gasifier design, control and additives (Ni et al., 2006). The hydrogen can be separated from the other gases by pressure swing adsorption.