Research on pyrolysis kinetics and products analysis of waste circuit boards
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摘要: 在氮气氛围下,利用热重分析(TGA)对废旧电路板(WPCB)非金属粉末进行热解动力学试验,并利用Py-GC∕MS(pyrolysis-gas chromatoraph∕mass spectrum)和TG(thermo gravimetric)∕MS测试手段对热解产物进行分析。结果表明,WPCB粉末热解过程经历水分蒸发、分解和稳定3个阶段,其中分解阶段包含有机质挥发分解和残渣分解2个过程,其表观活化能分别为250.74和23.58 kJ∕mol,指前因子分别为1.35×10 31和3 428.92 min -1。热解产物主要包括苯环取代的芳香族化合物和含溴化合物,此外还包括少量低分子量的碳氢化合物、苯并呋喃等。苯环取代的芳香族化合物主要包括苯、甲苯、乙苯、二甲苯、苯酚、异丙基苯酚;含溴化合物主要包括溴甲烷、溴乙烷、溴苯酚、二溴苯酚、溴化氢。Abstract: Under nitrogen condition, thermo gravimetric analysis(TGA) was used to test the pyrolysis characteristics and reaction kinetics of waste printed circuit boards (WPCB) powder. Py-GC∕MS and TG∕MS were used to analyze and discuss the pyrolysis products of WPCB. The results showed that the pyrolysis process of WPCB powder was divided into three stages, including evaporation of water, decomposition of organic matter and stabilization. The decomposition stage included volatilization and decomposition of organic matter and decomposition of residue, whose apparent activation energy was 250.74 and 23.58 kJ∕mol, respectively, and the pre-exponential factors were 1.35×10 31 and 3 428.92 min -1, respectively. The main products of the pyrolysis of the WPCB powder included aromatic compounds which mainly substituted by benzene ring-substituted aromatic compounds and bromine-containing compounds, and a small amount of low molecular weight hydrocarbons, benzofurans, etc. The benzene ring-substituted aromatic compounds mainly included benzene, toluene, ethylbenzene, xylene, phenol, isopropyl phenol, while the bromine-containing compounds mainly included methyl bromide, ethyl bromide, bromophenol, dibromophenol and hydrogen bromide.
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Key words:
- waste printed circuit board /
- pyrolysis kinetics /
- pyrolysis product
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