Co-treatment of swine manure and lignocellulosic biomass by liquefaction: Parameter optimization, product characterization, reaction mechanism

Abstract

In this study, co-treatment of swine manure (SM) and rice stalk (RS) or camphor tree woodchip (CTW) by liquefaction was explored for the synthesis of bio-oil and biochar products. Isochoric ethanol-water mixed solvent showed the best synergistic effect during the co-treatment of SM-RS/CTW. The effects of temperature, time, and feedstock/solvent mass ratio on the co-treatment of SM-RS/CTW obeyed a vulcano-type behavior, with recommended values of 230 ℃, 30 min, and 0.1 g/mL, respectively. The use of NaOH/Na2CO3 (5 wt% of feedstock) as the catalyst improved the production of bio-oil and the devolatilization performance of biochar. Compared with that of pure SM liquefaction, co-treatment of SM-RS/CTW enhanced the production of bio-oil and the energy recovery rate. Further, co-liquefaction bio-oil contained more ketone and phenolic compounds, while co-liquefaction biochar possessed a higher content of organic matter and more macropores. Overall, the co-treatment of SM-RS/CTW by liquefaction has considerable application prospects.