Low-Tar-Formation using High- Temperature Flash-Gasification of Intelligent Biomass Fuel Mixtures

Tar and other products of incomplete gasification (PIG) are known to cause great problems and losses in bio-fuel synthesis processes. Severe fouling and clogging in catalysts have been reported as well as reduced conversion efficiencies due to inert energetic gases. There are two ways of reducing PIG; primary and secondary methods. Primary measures concerns optimization of the gasifier and gasifier parameters or use of in-bed-catalysts or other additives. Secondary methods use syngas after treatment, i.e. process external methods like tar destruction, tar cracking and gas cleaning. The latter measures are often more expensive than the primary methods and often include several processing and cleaning steps. Primary methods should therefore be used to a maximum, potentially reducing the costs of secondary methods and thus of the total process concept. If the gasification temperature can be increased sufficiently over “normal ” gasification temperature (850°C) this together with process optimization can potentially be used to avoid the formation of tar components or for thermal cracking/oxidation to reduce the amount of already produced tars. However, previous studies have shown that many biomass fuels result in critica