制浆黑液固形物与工业木质素热解液化产物分析

Analysis on Pyrolysis Products from Black-liquor Solid and Technical Lignin

采用管式炉研究了纯化后的工业碱木质素和制浆黑液固形物在不同温度下的热解产物分布规律。借助热解-色谱-质谱(Py-GC-MS)联用、元素分析仪、ICP等离子发射光谱等分析了热解液相产物(热解油)和固体残余物的主要组成。研究表明,在600℃下热解,纯化后的工业碱木质素和黑液固形物热解油产率最高,且工业木质素热解油产率明显高于黑液固形物。热解油的产物非常复杂,纯化后的工业碱木质素和黑液固形物的热解油化学组成有较大的差异。纯化后的工业碱木质素热解油主要由各种低相对分子质量(Mr)的酚类、酮类、有机酸等物质组成,这些物质的相对含量明显高于黑液固形物热解产物中的含量,其中不含有黑液固形物的热解产物中相对含量较高的左旋葡萄糖,却出现了可能因热解缩合而形成的联苯结构。说明在黑液固形物热解液化前,对试样进行适当前处理,可在很大程度上调控其热解产物的组成。

The pattern of pyrolysis products distribution from purified technical alkali lignin and black-liquor solid under different temperatures were studied. The composition of liquid product （pyrolysis oil ） and solid residue from pyrolysis process were analyzed by pyrolysis-gas chromatography-mass spectrometry （Py-GC-MS）, elementary analysis and ICP plasma emission spectrum. Results showed the maximum yield of pyrolysis oil was obtained at 600 ℃, and the pyrolysis oil from alkali lignin was higher than that from black-liquor solid. The chemical composition of pyrolysis oil was very complicated, and components of pyrolysis oil from purified technical alkali lignin had lots of difference from that of black-liquor solid. The pyrolysis oil from purified technical alkali lignin was mainly consisted of low molecular phenolics, ketones, organic acids, etc. The relative contents of phenolics and organic acids in pyrolysis oil from technical lignin were obviously higher than those from black liquor solid. The relative content of laevoglucose was found to be higher in pyrolysis oil from black liquor solid than that from technical lignin, but biphenyl structure compound was detected in pyrolysis oil from technical lignin, which might be generated from condensation of intermediate products. The results give us the hint that it may be possible to control the composition of pyrolysis oil by suitable pretreatment of the black liquor.