On-Line Analysis and Kinetic Behavior of Arsenic Release during Coal Combustion and Pyrolysis
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- 作者：Fenghua Shen ; Jing Liu ; Zhen Zhang ; Jinxin Dai
- 刊名：Environmental Science & Technology
- 出版年：2015
- 出版时间：November 17, 2015
- 年：2015
- 卷：49
- 期：22
- 页码：13716-13723
- 全文大小：548K
- ISSN：1520-5851
文摘
The kinetic behavior of arsenic (As) release during coal combustion and pyrolysis in a fluidized bed was investigated by applying an on-line analysis system of trace elements in flue gas. This system, based on inductively coupled plasma optical emission spectroscopy (ICP-OES), was developed to measure trace elements concentrations in flue gas quantitatively and continuously. Obvious variations of arsenic concentration in flue gas were observed during coal combustion and pyrolysis, indicating strong influences of atmosphere and temperature on arsenic release behavior. Kinetic laws governing the arsenic release during coal combustion and pyrolysis were determined based on the results of instantaneous arsenic concentration in flue gas. A second-order kinetic law was determined for arsenic release during coal combustion, and the arsenic release during coal pyrolysis followed a fourth-order kinetic law. The results showed that the arsenic release rate during coal pyrolysis was faster than that during coal combustion. Thermodynamic calculations were carried out to identify the forms of arsenic in vapor and solid phases during coal combustion and pyrolysis, respectively. Ca3(AsO4)2 and Ca(AsO2)2 are the possible species resulting from As鈥揅a interaction during coal combustion. Ca(AsO2)2 is the most probable species during coal pyrolysis.