Interaction Characteristics of Mineral Matter and Nitrogen during Sewage Sludge Pyrolysis

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• 作者：Li-Hong Wei ; Li-Na Wen ; Mei-Jia Liu ; Tian-Hua Yang
• 刊名：Energy & Fuels
• 出版年：2016
• 出版时间：December 15, 2016
• 年：2016
• 卷：30
• 期：12
• 页码：10505-10510
• 全文大小：315K
• ISSN：1520-5029

文摘

The conversion of nitrogen-containing species in sludge is influenced by mineral matter. Raw sludge and demineralized sludge were pyrolyzed in a fixed-bed reactor in the temperature range of 500–800 °C to investigate the roles of the temperature and mineral matter on the nitrogen conversion in sewage sludge. To gain an in-depth knowledge and understanding of the nitrogen transformation mechanisms, we characterized the nitrogen-containing functional groups in raw sludge and chars via X-ray photoelectron spectroscopy, and the NO_x precursors (HCN and NH₃) were identified using a spectrophotometric method. According to the results, mineral matter has been proven to be able to affect the yields of char N, gas N, and other N (nitrogen in tar, N₂, NO, and others). The interaction between mineral matter and N-containing species in sewage sludge is strongly limited by the temperature. Mineral matter inhibits char N conversion at 500–600 °C and promotes char N conversion within the range of 600–800 °C. Meanwhile, mineral matter suppresses the yield of HCN but promotes the production of NH₃.