1 Zhengzhou Sewage Purifying Co., Ltd., Zhengzhou 450000, China
2 Zhengzhou Zhongyuan Wanyu New Energy Technology Co., Ltd., Zhengzhou 450000, China
3 State Key Laboratory of Clean and Efficient Coal Utilization, College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, China
4 Key Laboratory of Coal Science and Technology, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
Pyrolysis technology can achieve high-value utilization of sludge.However,the nitrogen (N) and sulfur (S) in sludge are easily converted into pollutants,such as NH3 and H2S.The migration pathways of N and S and the release mechanisms of N/S-containing pollutants during sludge pyrolysis were systematically elucidated.N in the sludge is primarily present as pyridinic and protein (>80%).During the low-temperature pyrolysis stage (<500℃),nitrogen in proteins,pyridine,and quaternary rapidly decompose into NH3,while HCN is released less.At high pyrolysis temperatures (>500℃),pyridine and protein deep cleavage increase the release of NH3 and HCN,and HCN can react with active hydrogen to generate NH3.Additionally,S in the sludge primarily exists as inorganic sulfur (over 70%).Thiophene and sulfoxide are converted to H2S and COS at 300℃,while ammonium sulfate decomposes to SO2 at 300-700℃.
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