Comparative study of the thermo‐catalytic reforming of agricultural and forest residue and advanced characterization of final products in a cold climate

Abstract

AbstractGlobal agricultural and forest residues hold promise for renewable fuel production through thermo‐catalytic reforming (TCR). Limited data exists on TCR outcomes for regions known for cold conditions like Canada. This study used a 2 kg h−1 TCR unit for the intermediate pyrolysis/reforming of agricultural (wheat straw pellet, WSP) and forest (softwood pellet, SWP) residues. Maximum bio‐oil yields were 8.43% for wheat straw pellets and 7.99% for softwood pellets at 400 and 500°C reactor and reformer temperatures. Feedstock, bio‐oil, and biochar properties were analyzed through proximate and ultimate analysis. At 550°C reactor and 700°C reforming temperatures, 70.73% of the wheat straw pellet‐based gas yield contained 36.11 vol.% H2 and 11.08 vol.% CH4, giving a higher heating value (HHV) of 12.54 MJ kg−1. A high concentration of CH4 (22.02 vol.%) in the softwood pellet‐based gas gave an HHV of 17.94 MJ kg−1. The low viscosity (3.9 mPa · s−1) and total acid number (7.3 mg KOH g−1) wheat straw pellet‐based bio‐oil had an O/C molar ratio of 0.09 and an HHV of 35.80 MJ kg−1. The 400/600°C reactor/reformer temperatures gave the lowest area percentage of mono‐aromatic (16 vol.%) and polycyclic aromatic (11.20 vol.%) compounds in the softwood pellet bio‐oil. The O/C molar ratio (0.5–0.6) in softwood pellet biochar elevated the higher heating value from 32.37 to 34.57 MJ kg−1. The study results guide optimal TCR unit operation in cold climates like Canada with local feedstocks, emphasizing its notable hydrogen production over bio‐oil and biochar.