Comparative study of catalytic and non-catalytic steam reforming of bio-oil: Importance of pyrolysis temperature and its parent biomass particle size during bio-oil production process

•Bio-oil from biomass with a small particle size can generate more gases.•Bio-oil produced with maximum is not suitable for syngas production.•Bio-oil with high oligomers produces more tar and aromatic molecular structures.•Organic fraction of bio-oil determines the gas yield to a great extent.•Bio-oil with low oligomers and high organics is suitable for syngas production.