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摘要为了研究三氟甲烷灭火剂在B类火焰作用下的热分解规律，实验以杯式燃烧器为基础设计并搭建了一套具有原料控制输送、尾气采集、温度采集等功能的试验系统，分别采用气相色谱/质谱（GC/MS）、离子色谱（IEC）、热电偶树测温系统等仪器进行尾气组成、HF含量和燃烧区温度的测量。实验研究时，以无水乙醇为B类火焰燃料，空气流量为150L/h，三氟甲烷体积分数分别为3.7%，7.1%，10.3%，13.3%。实验结果表明：在火焰熄灭前随着三氟甲烷体积分数的增大，火焰的高度变大、宽度变小，当达到灭火浓度时，火焰瞬间熄灭；燃烧区域温度随三氟甲烷体积分数的增大而小幅度增大，火焰熄灭时温度瞬间下降；三氟甲烷在四个体积分数下均热解生成HF，并且随着体积分数的增大， HF的浓度先增加后减少；三氟甲烷在无水乙醇火焰作用下发生热解脱HF生成卡宾自由基的反应，卡宾自由基与三氟甲烷反应生成五氟乙烷。由此可见，用三氟甲烷抑制乙醇火焰时，随着向燃烧区输送的三氟甲烷灭火剂浓度的增大，乙醇的燃烧非但没有减弱反而逐渐增强了，产生的HF毒气也有增加的过程。尾气中除三氟甲烷和空气外，主要为二氧化碳和五氟乙烷。63638
毕业论文关键词 三氟甲烷 Ｂ类火焰 相互作用 热分解
毕业设计说明书（论文）外文摘要
Title The Study on Thermal Decomposition Mechanism of Trifluoromethane when it Interacts with the Class B Flame
Abstract
To study the pyrolysis properties of trifluoromethane fire extinguishing agent when it interacts with the class B flame, an experimental research system based on cup burner with functions that supplying raw material according to requirements, tail gas gathering and temperature acquisition was designed and built. The composition of tail gas, the HF contents and the temperatures of the burning zone were detected by gas chromatography/mass spectrometry (GC/MS), gas chromatography (GC) and the temperature measurement system of thermocopule tree respectively. In the experimental study, the anhydrous ethanol was selected as the fuel of class B flame , the air flow rate was 150L/h and the concentration of trifluoromethane were 3.7%，7.1%，10.3% and 13.3% respectively. The results show that: (1) Before the flame is extinguished, the flame height became bigger and the flame width became smaller as the concentration of trifluoromethane increased, when fire extinguishing concentration is reached, the flame will be instantly extinguished.(2)The temperatures of the burning zone slowly increased as the concentration of trifluoromethane increased and instantaneously dropped when the flame was extinguished.(3) The pyrolysis of trifluoromethane produced HF at four concentrations, and the concentration of HF increased firstly and reduced later as the concentration of trifluoromethane increased.(4) Fluoride elimination was the most feasible reaction in the pyrolysis of trifluoromethane with anhydrous ethanol fire, and the carbene radicals were generated at the same time. Then the carbene radicals reacted with trifluoromethane to form the pentafluoroethane. Therefore, when trifluoromethane was used to inhibit the ethanol flame, the combustion of ethanol was not decreased but enhanced as the concentration of trifluoromethane into the burning zone increased and the content of HF also had a growth. The tail gas mainly contained carbon dioxide and pentafluoroethane except trifluoromethane and air.
Keywords trifluoromethane class B flame interact thermal decomposition
1 引言 1
1.1 研究背景 1
1.2 三氟甲烷简介 2
1.2.1 物理性质