Influence of temperature on pyrolysis of recycled organic matter from municipal solid waste using an activated olivine fluidized bed

Pyrolysis of an organic concentrate from municipal solid waste was carried out using a bench-scale fluidized bed reactor at 350–540 °C comparing Al2O3 with activated olivine sand as bed materials. A maximum oil yield of 50 wt.% was obtained using the activated olivine sand at 400 °C while only 45 wt.% was obtained at 500 °C using Al2O3. The bio-oils using activated olivine sand at 400 °C had an H/C ratio of 1.50 and O/C ratio of 0.37 and were less aromatic and less nitrogenous compare to the oils obtained using Al2O3 at 400 °C where the H/C ratio was 1.32 and the O/C ratio was 0.44. The aromatic compounds were found to be reduced while the aliphatic compounds increased in the oils generated using activated olivine sand. The calorific value of the bio-oil at 500 °C was 29 MJ/kg using activated olivine sand while the bio-oil using Al2O3 was 23 MJ/kg. The presence of iron, magnesium and other oxides probably promotes the removal of oxygen, which indicates that the activation energy of C―O bond breakage is reduced compared to the C―C bonds, thus promoting dehydration, decarboxylation and alkalation reactions to produce aliphatic fatty acid at lower temperatures.