纳米金属氧化物对六氟丙烷热分解性能的影响研究

【作者】 高飞；

【导师】 潘仁明；

【作者基本信息】 南京理工大学 ， 安全技术及工程， 2010， 硕士

【摘要】 为了提高氢氟烃灭火剂的灭火性能,为氢氟烃灭火剂与添加剂的协同灭火作用研究提供参考,在系统分析和总结前人研究的基础上,本文设计并搭建了一套具有原料定量输送、程序控制升温及在线色谱分析等功能的热分解实验系统,采用气相色谱(GC)、气相色谱质谱联用(GC/MS)、傅里叶变换红外光谱(FTIR)、氟离子选择电极法、离子色谱法等分析和测试技术研究了六氟丙烷(HFC-236fa)在不同反应温度、不同驻留时间下的热分解产物及特点,尤其探讨了相同条件下加入纳米氧化镁(MgO)和纳米氧化铈(CeO2)后HFC-236fa热分解反应过程及产物发生的变化,采用X射线衍射仪(XRD)、FTIR等方法分析了纳米MgO和纳米CeO2加入前后表面成分变化,分析其对热分解反应产生影响及原因,主要研究结果如下：(1)HFC-236fa性能稳定,在500℃时不发生分解,600℃开始发生微弱分解,700℃、800℃发生强烈分解。HFC-236fa在热分解过程中主要发生脱氟化氢的反应,HFC-236fa的分解率随反应温度升高及驻留时间增长而增加。此外,700℃以上HFC-236fa分解时在反应器壁上观察到焦炭的生成。(2)在反应器中加入纳米MgO后HFC-236fa的分解率提高,说明纳米MgO能促进HFC-236fa热分解。反应后部分纳米MgO转化成MgF2,随温度升高,MgF2生成量增加,使热分解气体中HF的含量减少的同时,对热分解起到进一步促进作用。(3)加入纳米CeO2后,HFC-236fa分解率加大,但比相同条件下加入纳米MgO后分解率低,热分解产物种类比加入纳米MgO后多,检测到F3—CF(CF3)—CF2—CF3等新物质,同时纳米CeO2表面生成CeF3,随温度升高,CeF3的粒径而不断变大,晶格逐渐趋向完善。更多还原

【Abstract】 To improve fire extinguishing performance of HFCs extinguishing and give reference to the research on its extinguishing fire in cooperation, an experiment research system with functions that supplying raw material according to requirements, programmed temperature and gas chromatography was designed on the basis of former research. The products of thermal decomposition of HFC-236fa at different temperatures and residence times were analyzed through using gas chromatography (GC), gas chromatography/mass spectrometry (GC/MS), Fourier transform infrared spectrum (FTIR), fluoride ion-selective electrode (FISE) and ion chromatography. The changes of products and process in the thermal decomposition after adding to Nano-MgO and Nano-CeO2 were specially investigated. The changes of the composition of Nano-MgO were studied by using X-ray diffraction and FTIR for further research. The reasons of the changes in the thermal decomposition were studied seriously. The conclusions were summarized as following:(1)HFC-236fa was steady at 500 degree. It started to decompose at 600 degree and has the intense decomposition at 700 or 800 degree. Fluoride elimination was the most feasible reaction in thermal decomposition of HFC-236fa.The decomposition of HFC-236fa became stronger with the increase of the temperatures and the enhancement of residence times.(2)The decomposition of HFC-236fa became stronger after adding to Nano-MgO. This illustrated that Nano-MgO make the thermal decomposition stronger. MgF2 was found on the Nano-MgO after reaction and the concentration of the MgF2 increased with the increase of the temperatures, it made that the concentration of the HF produced from the decomposition was obviously decreased.(3)The decomposition of HFC-236fa became stronger after adding to Nano-CeO2, the decomposition rate was lower than that adding to Nano-MgO, but the products were more. F3C—CF(CF3)—CF2—CF3 was first found. CeF3 was found on the Nano-CeO2, its size was larger and more perfect as the increase of the temperature.更多还原