Hydrothermal liquefaction of corn straw under CO atmosphere: Effect of catalysts

Abstract-the effects of different catalysts (homogeneous catalysts: NaOH, Na₂CO₃, KOH and K₂CO₃; heterogeneous catalysts: JB-1, JT-201 and JT-203) on the hydrothermal liquefaction of biomass under CO atmosphere were investigated mainly using a high-pressure autoclave reactor at 380°C. The results indicated that the conversion of biomass and the yield of liquid products increased obviously with the adding of the catalysts. Compared with the raw material, the conversion of corn stalk increased from 82.3% to 93.3-99.9%, the H/C molar ratio and the higher heating value (HHV) increased, the contents of both hydrogen and carbon increased significantly, and the contents of oxygen, nitrogen and sulfur reduced in liquid products. The activity order of the catalysts was as follows: CO₃²>;OH^-; Na⁺>; K⁺. JT-203 was the most effective of the three commercial catalysts. For the biomass deoxidization, heterogeneous catalysts were more effective than homogeneous catalysts.