Effect of hydrothermal carbon on biogas production from agricultural waste by anaerobic fermentation

In this study, biogas residue was used as raw material to prepare biogas residue by hydrothermal carbonization at 190℃ with different treatment time. The effects of hydrothermal carbon addition on gas production characteristics during medium temperature anaerobic fermentation (straw, straw + chicken manure, chicken manure) were studied, and the differences of surface formation of biogas residue hydrothermal carbon were observed by SEM. The results showed that the duration of gas generation peak was prolonged in the straw + chicken manure fermentation group and the chicken manure fermentation group after adding biogas residue hydrothermal charcoal, and the total gas production in the 8h, 12h and 24h hydrothermal charcoal groups increased more (P < 0.05), and the total gas production increased 39.2% at most. There was no significant difference in cumulative gas production among groups in straw fermentation group. According to the actual production, the optimal HTC process for anaerobic fermentation is 8 h at 190℃.