Catalytic pyrolysis of biomass using fly ash leachate to increase carbon monoxide production and improve biochar properties to accelerate anaerobic digestion

• Published in: Bioresource technology 2023-11, Vol.387, p.129583-129583, Article 129583
• Main Authors: Kobayashi, Takuro, Kuramochi, Hidetoshi
• Format: Article
• Language: English
• Subjects: Anaerobic digestion; Biochar; CO2-assisted pyrolysis; Fly-ash
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2023.129583

[Display omitted] •Fly-ash leachate doubled CO production via catalyzed CO2 gasification at 800 °C.•CO2 increased specific surface area and porosity of the pyrolysis biochar.•Fly-ash leachate enhanced wettability and electroactive surface area of biochar.•CO2 and ash-amended biochar significantly shortened the digestion time of waste oil. Biomass-derived biochar is attracting growing interest as an effective additive for anaerobic digestion (AD). To improve energy yield and digestion performance through an integrated process of biochar production and AD, biochar upgrading using biomass fly ash leachate as a sustainable metal catalyst was investigated. The results indicate that the bark soaked in the leachate improved the pyrolysis reactivity of biomass with CO2 and reduced the temperature at which the reaction rate reached its maximum from 943 °C to 801 °C. This resulted in a doubling of CO production during CO2-assisted pyrolysis at 800 °C. In addition, the combined use of fly ash leachate and CO2 in bark pyrolysis improved not only the porosity of the resulting biochar but also its wettability and liming potential. Moreover, biochar amended with fly ash leachate and CO2 significantly reduced the lag time in the anaerobic digestion of grease trap waste.