This work present a novel primary method, for tar reduction in downdraft gasification. The principle of
this new technology is to change the fluid dynamic behaviour of the mixture, formed by pyrolysis
product and gasification agent in combustion zone; allowing a homogeneous temperature distribution in
radial direction in this reaction zone. To achieve the change in the fluid dynamic behaviour of the
mixture; the entry of gasification agent to combustion zone is oriented by means of wall nozzles in order
to form a swirl flow. This modification in combination with the extension of the reduction zone, will
allow, to increases the efficiency of the tar thermal cracking inside the gasifier and the extension of the
Boudouard reactions. Consequently, the quantity of tar passing through the combustion zone without
cracking and the concentration of tar in the final gas, decrease significantly in relation with the common
value obtained for this type of reactor, without affecting significantly the heating value of the producer
gas. In this work is presented a new design for 15 kW downdraft gasification reactor, with this technology
implemented, the tar content obtained in the experiments never overcome 10 mg/Nm3
, with a
lower heating value of 3.97 MJ/Nm3
.