Influence of NH concentration on biomass nitrogen-enriched pyrolysis.

In this study, nitrogen was used to replace oxygen through biomass N-enriched pyrolysis in a fixed-bed reactor to obtain N-containing chemicals and N-doped biochar. Influence of NH concentration on the formation mechanism of N-species and electrochemical performance of N-doped biochar was investigated in depth. Results showed that increasing NH concentration promoted bio-oil and gas generation, and increased H, CH and CO yield at the diminishing of CO. Simultaneously, bio-oil showed lower oxygen content with non-methoxy phenols and N-heterocyclics as the main components, and the maximums were 57.73% and 16.21% at 80 vol% NH concentration, respectively. With regard to solid N-doped biochar, nitrogen content (4.85 wt%), N-containing groups and specific surface area (369.59 m/g) increased greatly, and excellent electrochemical property (120 F/g) was shown with NH concentration increasing. However, NH conversion efficiency decreased gradually with NH increasing, and 40 vol% may be the optimum NH concentration for biomass N-enriched pyrolysis.