A
typical gas composition from biomass gasification in a downdraft
reactor with air used as an oxidizing agent is as follows: 15e20% of
H2, 15e20% of CO, 0.5e2% of CH4, 10e15% of CO2 and the remaining
part is made of N2, O2 and CxHy. On the other hand, if oxygen or
water steam or a mixture of both these is used, then the concentration
of combustible components is significantly increased and
the calorific value rises to 18 MJ/Nm3