NOx and N2O precursors from biomass pyrolysis: role of cellulose, hemicellulose and lignin.

Cellulose, hemicellulose, and lignin play important roles in biomass. Nitrogen in biomass is mainly in forms of proteins (amino acids). Two amino acids, proline and glutamic acid, with different structures were selected as the nitrogen-containing model compound in biomass. Interaction between the two amino acids with cellulose, hemicelluloses, or lignin at different weight ratios was investigated to understand nitrogen chemistry. Considering the composition of wood and agricultural straw, proline and the mixture of cellulose, hemicellulose, and lignin were pyrolyzed under the same condition. Nitrogen transformation during copyrolysis of amino acid with the component at different ratios was identified to determine the role of cellulose, hemicellulose, and lignin. The emissions of HCN and NH3 were detected with a Fourier transform infrared (FTIR) spectrometer. The results indicate that although the structure of the amino acid has a significant effect on the nitrogen transformation during pyrolysis, it is interesting to find some characteristics in common for the aliphatic amino acid and heterocyclic amino acid. The effects of hemicellulose on NH3 formation from the two amino acids are similar, hemicellulose inhibits N-NH3 conversion and lignin promotes NH3 formation for the two amino acids.