| Study | Production method | Main findings | Reference |
| MW and slow pyrolysis biochar | slow pyrolysis and MW pyrolysis | ・ MW assisted pyrolysis starts at 200˚C, while in case of conventional heating a higher temperature and residence time was required to obtain similar results | [62] |
| Production of solid biochar fuel from waste biomass | HTC | ・ energy density of biochar increased with increasing hydrothermal temperature ・ most hemicellulose and cellulose were decomposed below 250˚C while the degradation of lignin only occurs at higher temperatures ・ biochar yield decreased rapidly with increasing temperature | [61] |
| Effects of feedstock type, production method, and pyrolysis temperature on biochar and hydrochar properties | slow pyrolysis | ・ the production method showed strong effect on biochar properties. ・ higher pyrolysis temperatures produced higher thermal stability biochars ・ biochar yields decreased with increasing temperature and when peak temperature rose from 200˚C to 600˚C, carbon contents increased and oxygen and hydrogen contents decreased | [65] |
| Comparison of kiln-derived and gasifier-derived biochars as soil amendments in the humid tropics | kiln-produced biochar | ・ highest estimated temperature reached inside the kiln was 400˚C and 600˚C at the top and between 600˚C and 800˚C at the bottom ・ biochar yields were 140 - 290 g∙kg−1 of the initial biomass weight for eucalyptus, 240 - 250 g∙kg−1 for maize cobs, 450 - 490 g∙kg−1 for rice husks, 360 - 430 g∙kg−1 for coffee husks, and 290 - 320 g∙kg−1 for groundnut shells | [66] |
| Production and characterization of bio-oil and biochar from rapeseed cake | fixed bed pyrolysis | ・ H/C: 0.47, O/C: 0.27, AC: 17.6%, VM: 18.7%, FC: 63.7% ・ biochar obtained are carbon rich, with high heating value and relatively pollution-free potential solid biofuel | [67] |