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To better understand biomass pyrolysis, the different roles of the three components (hemicellulose, cellulose, and lignin) in pyrolysis are investigated in depth using a thermogravimetric analyzer (TGA). The pyrolysis characteristics of the three components are first analyzed, and the process of biomass pyrolysis is divided into four ranges according to the temperatures specified by individual components. Second, synthesized biomass samples containing two or three of the biomass components are developed on the basis of a simplex-lattice approach. The pyrolysis of the synthesized samples indicates negligible interaction among the three components and a linear relationship occurring between the weight loss and proportion of hemicellulose (or cellulose) and residues at the specified temperature ranges. Finally, two sets of multiple linear-regression equations are established for predicting the component proportions in a biomass and the weight loss of a biomass during pyrolysis in TGA, respectively. The results of the calculations for the synthesized samples are consistent with the experimental measurements. Furthermore, to validate the computation approach, TGA experimental analysis of the three components of palm oil wastes, a local representative biomass sample, is conducted.

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Transformation and evolution mechanisms of nitrogen during algae pyrolysis were investigated in depth with exploration of N-containing products under variant temperature. Results indicated nitrogen in algae is mainly in the form of protein-N (∼90%) with some inorganic-N. At 400-600 °C, protein-N in algae cracked first with algae pyrolysis and formed pyridinic-N, pyrrolic-N, and quaternary-N in char. The content of protein-N decreased significantly, while that of pyrrolic-N and quaternary-N increased gradually with temperature increasing. Pyridinic-N and pyrrolic-N formation was due to deamination or dehydrogenation of amino acids; subsequently, some pyridinic-N converted to quaternary-N. Increasing temperature decreased amides content greatly while increased that of nitriles and N-heterocyclic compounds (pyridines, pyrroles, and indoles) in bio-oil. Amides were formed through NH reacting with fatty acids, that underwent dehydration to form nitriles. Besides, NH and HCN yields increased gradually. NH resulted from ammonia-N, labile amino acids and amides decomposition, while HCN came from nitrile decomposition. At 700-800 °C, evolution trend of N-containing products was similar to that at 400-600 °C. While N-heterocyclic compounds in bio-oil mainly came from pyrifinic-N, pyrrolic-N, and quaternary-N decomposition. Moreover, cracking of pyridinic-N and pyrrolic-N produced HCN and NH. A mechanism of nitrogen transformation during algae pyrolysis is proposed based on amino acids decomposition.