We present results of an experimental study on two-stage wood gasification
and attempts to reduce the tar content of the gas. Increasing the wood-chip
moisture content resulted in an increase of CO2 and H-2, bur a decrease of
the CO concentration without significantly affecting the tar content in th
e producer gas. For a particular primary air flow rate, an increase in the
secondary air flow of the two-stage gasifier resulted in decrease of the ta
r content and the CO2 and H-2 concentrations while that of CO increased. A
charcoal gasifier and a floating-drum gas storage system were coupled to a
two-stage wood gasifier. The tar content of the product gas was in the rang
e 19-34 mg/Nm(3) for a charcoal gasifier coupled to a two-stage wood gasifi
er. With a floating-drum gas-storage system and a 3.5 h retention time, the
tar content was reduced to 9.24 mg/Nm(3), which is 85% less than that obta
ined by using the a two-stage wood gasifier alone. (C) 1999 Published by El
sevier Science Ltd. All rights reserved.