Chars produced from the pyrolysis of different waste materials have been investigated in terms of their
use as a catalyst for the catalytic cracking of biomass pyrolysis gases during the two-stage pyrolysisgasification
of biomass. The chars were produced from the pyrolysis of waste tyres, refused derived fuel
and biomass in the form of date stones. The results showed that the hydrocarbon tar yields decreased
significantly with all the char materials used in comparison to the non-char catalytic experiments. For
example, at a cracking temperature of 800 C, the total product hydrocarbon tar yield decreased by
70% with tyre char, 50% with RDF char and 9% with biomass date stones char compared to that without
char. There was a consequent increase in total gas yield. Analysis of the tar composition showed that the
content of phenolic compounds decreased and polycyclic aromatic hydrocarbons increased in the product
tar at higher char temperatures.