Production of biochar from waste biomass using slow pyrolysis: Studies of the effect of pyrolysis temperature and holding time on biochar yield and properties

Abstract

The present study deals with developing biochar from the waste biomass using slow pyrolysis at dynamic temperatures (400, 600, and 800 °C) and holding times (30, 45, and 60 min). The produced biochars were characterized by their thermal, physical, and chemical properties. The biomass characterization confirmed its candidacy for being used as a biochar feedstock. An XRF study of ash content confirmed that biomass has a lower possibility of slagging and fouling issues. A kinetic study of biomass confirmed that activation energy increased substantially (34.37–90.34 and 22.74–63.92 kJ mol−1 for MWS and CNW, respectively) by varying the reaction order. The outcomes of the pyrolysis process revealed that elevating the pyrolysis temperature from 400 to 800 °C resulted in a decrease in the yield of biochar, accompanied by an increase in its carbon content. XRD study of biochar established that rising pyrolysis temperature caused a change in the mineral content of biochar. HHV and bulk density of biochar were found to be increased by increasing pyrolysis temperature from 400–800 °C. Moreover, it was observed that BET surface area and Zeta potential increased as the pyrolysis temperature rose from 400–800 °C. FE-SEM study of biochar, established by increasing temperature from 400–800 °C, accelerated the volatilization activity and caused a considerable surface modification in the resulting biochar. Overall, biochar displayed various mineralogical compositions, surface alteration, high thermal stability, carbon content, and pH, making them appropriate for strengthening the procedures of different industrial applications.

Keywords

• Waste biomass
• Kinetics
• Slow pyrolysis
• Biochar
• Thermal stability
• Morphology