Investigation of pathways for transformation of N‑heterocycle compounds during sewage sludge pyrolysis process
| Autor: | Zhixia He, Xun Hu, Zhi-Xiang Xu, Qian Wang, Lin Xu, Jin-Hong Cheng |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
chemistry.chemical_classification
Nitrile Chemistry 020209 energy General Chemical Engineering Energy Engineering and Power Technology Salt (chemistry) 02 engineering and technology 010501 environmental sciences 01 natural sciences Decomposition Amino acid chemistry.chemical_compound Fuel Technology Polymerization 0202 electrical engineering electronic engineering information engineering Organic chemistry Pyrolysis Sludge 0105 earth and related environmental sciences Macromolecule |
| Zdroj: | Fuel Processing Technology. 182:37-44 |
| ISSN: | 0378-3820 |
| DOI: | 10.1016/j.fuproc.2018.10.020 |
| Popis: | This study investigated the transformation of N‑heterocycle compounds during sewage sludge pyrolysis process. The reaction pathways for evolution of the products especially the N-containing organics such as amino acids‑N were analyzed in detail. NH3 is the main N-containing gaseous product during the pyrolysis and its concentration was increased with the increasing temperature. Phenolic compounds, hydrocarbons and heterocyclic compounds were the main component in liquid products. The in situ FT-IR study showed that the labile inorganic ammonium salt decomposition proceeded to completion below 500 °C. Above 500 °C N‑heterocycle compound was formed and then it was decomposed, while above 600 °C nitrile started to decompose. NH3 formation main originates from the decomposition of N‑heterocyclic compounds and nitrile. Proteins during the pyrolysis, as verified by XPS, were mainly converted into inorganic nitrogen. In addition, the Py-GC–MS results showed that large amount of N‑heterocyclic compounds were found in amino acid‑N pyrolysis products. The transformation paths for the amino acids with different chemical structures were distinct. Except N‑heterocyclic amino acids, long chain aliphatic amino acid also can form N‑heterocyclic compounds through cyclization. In addition, the decomposition of the intermediates of N‑heterocyclic compounds form small molecular compounds or while the polymerization of the intermediates forms macromolecule compounds. The amino acids with heterocycle structure were disrupted to form heterocycle and aliphatic intermediate. The plausible mechanism of sewage sludge pyrolysis was proposed. |
| Databáze: | OpenAIRE |
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