基于热重分析的硫化亚铁氧化倾向性研究

含硫油品储罐内壁腐蚀产物硫化亚铁在空气中有很高的氧化性,很容易引起储罐火灾爆炸事故.用美国TA公司生产的SDT-Q600同步热分析仪在30～1 000 ℃范围内对硫化亚铁进行热重分析,从物理吸附、化学吸附和化学反应的角度分析了硫化亚铁氧化过程,讨论了粒径和升温速率对硫化亚铁TG曲线的影响.结果表明,硫化亚铁经物理吸附和化学吸附,发生了剧烈的化学反应,并放出大量热;粒径和升温速率对TG曲线有明显的影响,粒径减小,TG曲线向低温方向移动,氧化起始温度和氧化终止温度降低;升温速率增大,TG曲线向高温方向移动,氧化速度减小.

Study on the oxidation tendency of ferrous sulfide based on thermo-gravimetric analysis

The present article is to present our study of the oxidation tendency and likeliness of ferrous sulfide to cause explosive accidents in the oil tank with sulfur. As is known, the oxidation of ferrous sulfide, i.e. the corrosion products in an oil tank, may have a strong tendency to get oxidized. Therefore, this study focus has been put on the thermo-gravimetric analysis of the oxidation of ferrous sulfide samples, known as SDT-Q600 made by TA company in the USA within the range from 30 ℃ to 1 000 ℃. In our work, the oxidation process has been analyzed from different points of view, such as from that of physical adsorption, chemical adsorption and chemical reaction. The investigation on the effects of different particle sizes and heating rates on TG curve has also been done. The results show that the process of ferrous sulfide reacts with the oxygen can be described as that from constant weight to the weight increment, then turn to the rapid weight loss. In this process, the reaction can be said the one which goes violently after the physical and chemical adsorption with much heat released. The fire or explosive accident that may result in the oil tank with sulfur is by nature heat-cumulative. The particle size of ferrous sulfide and heating rate are likely to have significant influence on TG curve, which may turn noticeably to the lower temperature as the particle size decreases. And so are the initial oxidizing temperature and the final temperature. Thus, it shows that the danger of spontaneous combustion of ferrous sulfide may have thus increased with the decrease of particle size. And in turn the fire or explosive accidents in the oil tank are likely to take place promptly, too. Therefore, it can be found that the TG curve shifts to higher temperature and the oxidation speed decreases with the increase of heating rate actually imply that we should choose a suitable heating rate for our experimentation in order to keep its results in conformity with the actual situation. And so the conclusions here made can provide reference to fire prevention of or oil explosion in the oil tank.