硫铁化合物低温氧化过程及动力学研究

发布时间：2018-04-25 08:53

  本文选题：硫铁化合物 + 低温氧化　； 参考：《郑州大学》2015年硕士论文

【摘要】：本文对设备腐蚀样品氧化固态中间产物的物相及表面特性和气态产物释放规律展开研究;结合均相沉淀样品,对硫铁化合物的氧化诱导期以及氧化动力学过程进行研究。通过低温预氧化实验,对设备腐蚀样品的固态中间产物运用拉曼光谱分析和X射线衍射分析表明,预氧化前设备腐蚀样品多以非晶态硫化亚铁的形式存在,预氧化后样品呈现为一个多相体系;采用BET法对其表面特性分析得出,随着预氧化时间的延长,产物比表面积减小,孔隙率随之减小。运用热重-傅里叶转换红外光谱联用手段研究设备腐蚀样品氧化热解过程及气体释放规律进行研究。结果表明,氧化热解气态产物包括SO2、SO3和少量的水,当温度达到715℃时SO2析出量达到最大值;热解残余产物分析表明,S8不适于在硫铁化合物氧化反应中作为定量分析的指标性产物。通过氧化诱导期实验对设备腐蚀样品和均相沉淀样品的热稳定性及影响因素的研究表明,两种样品在125~200℃内处于活跃的自热阶段,热稳定性较差;对于超微粒径和大颗粒的样品均不利于硫铁化合物的氧化反应,粒径范围44~74μm的样品氧化诱导时间最短,自燃倾向性越高;升温速率导致样品的比表面积降低同时增强了样品的气体脱附能;空气流速对诱导期的影响较小。采用热重-差示热扫描联用分析了设备腐蚀样品和均相沉淀样品在多重升温速率下的氧化热解过程,运用Friedman,Starink和Kissinger三种非模型动力学方法计算得出了两种样品在各氧化阶段的表观活化能。分析表明,硫铁化合物在151.4~417℃内逐步进行物相转化,450.5~533.5℃内开始Fe S2的氧化热解,668.8~840.7℃内硫酸盐(或亚硫酸盐)分步分解,热解失重达到最大值;热解失重阶段均有SO2的析出,在低温阶段,SO2主要由物相转化时析出的单质硫氧化生成,而高温段硫酸盐的分步热解是SO2生成的主要原因。
[Abstract]:In this paper, the phase and surface characteristics of solid intermediate products and the release law of gaseous products were studied, and the oxidation induction period and oxidation kinetics of ferric sulfide compounds were studied in combination with homogeneous precipitated samples. By means of low temperature preoxidation experiments, Raman spectroscopy and X-ray diffraction analysis of the solid intermediate products of the equipment corrosion samples show that the corrosion samples are mostly in the form of amorphous ferrous sulfide before preoxidation. The surface properties of the samples were analyzed by BET method. The results show that the specific surface area decreases and the porosity decreases with the increase of preoxidation time. The oxidation pyrolysis process and gas release of corrosion samples were studied by thermogravimetric Fourier transform infrared spectroscopy (TFTIR). The results show that the oxidation pyrolysis gaseous products include so _ 2 so _ 3 and a little water, and the SO2 precipitation reaches the maximum value when the temperature reaches 715 鈩，

本文编号：1800638