废弃印刷线路板热解油的分析

Analysis of Pyrolysis Oil from Waste Printed Circuit Boards

在固定床实验装置上进行 FR4型印刷线路板的热解,利用气相色谱-质谱、傅里叶变换红外光谱分析了热解油的组成,用氧弹式量热仪测定了热解油各馏分的热值,并初步探讨了溴化环氧树脂的热解机理。实验结果表明,FR4型印刷线路板热解产物中热解油的质量分数为18.23%。热解油由轻质馏分、重质馏分和石油蜡组成。轻质馏分中包括少量水和轻质油。轻质油的主要组分为苯酚、4-乙基苯酚、3-(1-甲基乙基)-苯酚、5-甲基-乙基苯,其他组分主要为烷基取代的苯和苯酚,还含有丙酮及少量其他含氧有机物(苯甲醚和苯并呋喃等),轻质油中溴含量较低。重质馏分和石油蜡所含官能团与轻质油基本相同。轻质油和重质馏分的低位热值分别为27 183 kJ/kg 和29 240 kJ/kg。溴化环氧树脂的热解反应存在 CH_2-O,C-C,CH-OH,C-Br 键的断裂。

FR4-type waste printed circuit boards were pyrolysed in a fixed bed reactor and the obtained pyrolysis oil was analysed by GC-MS and FFIR. Caloric values of fractions in pyrolysis oil were measured by oxygen bomb calorimeter. Pyrolysis mechanism of brominated epoxy resin was discussed together with analysis of pyrolysis products. 18.23% （ mass fraction） of pyrolysis oil was obtained from the pyrolysis of FR4-type waste printed circuit boards. It mainly consists of light fraction, heavy fraction and petroleum wax. Light fraction contains a small amount of water and balanced amount of light oil. Light oil mainly contains phenol, 4-ethyl-phenol, 3-（ 1-methylethyl）- phenol, ethylpentamethyl-benzene, other substituted benzenes and substituted phenols. Acetone, methoxybenzene and benzopyrans were detected in the light oil, as well as a small amount of bromide- contained compound. Functional groups of heavy fraction and petroleum wax are identical with those of light oil, i. e. , the main components are phenols and other aromatics. Low caloric values of light oil and heavy fraction are up to 27 183 kJ/kg and 29 240 kJ/kg, respectively. Cleavage of molecule bonds of CH2-O, C-C, CH-OH, and C-Br occurs in the pyrolysis of brominated epoxy resin.