We have investigated the improvement in the quality of bio-oils by catalytic co-pyrolysis of sawdust and tyre mixture in an integrated reactor. The vapours from co-pyrolysis are allowed to pass through a desulfurising layer composed of zinc oxide and then through the catalytic layer consisting of silver (Ag), palladium (Pd), molybdenum (Mo), or vanadium (V) supported over SBA-15 or HZSM-5. The bio-oils produced by the condensation of vapours are systematically analysed using an elemental analyser, calorimeter, gel permeation chromatograph, densimeter, viscometer, and thermal analyser. Results indicate that the quality of bio-oils can be effectively improved by using Ag/SBA-15 and Pd/SBA-15. The typical bio-oil (SSS40) produced by co-pyrolysis of the mixture containing 40 wt.% sawdust and 60 wt.% tyre with Ag/SBA-15 catalyst have properties similar to that of the diesel fuel no. 0 #. On the other hand, the molecular weight distribution of the upgraded bio-oils obtained from the mixture of 40 wt.% saw dust and 60 wt.% waste tyre with Ag/HZSM-5 as catalyst is close to that of commercial diesel fuel no. 0#. Based on the results, we have also proposed the kinetics associated with the combustion of typical upgraded bio-oil.
Keywords: sawdust, catalysis, co-pyrolysis, tyre, bio-oil, upgrade