快速热解生物油柱层析分离与分析

COLUMN CHROMATOGRAPHIC SEPARATION OF BIO-OIL FROM FAST PYROLYSIS OF BIOMASS

利用柱层析分离与分析了自由落下床反应器中杏核和玉米芯快速热解油。生物油经脱水、抽提分离出 沥青烯后,柱层析分离成3个馏分:环己烷洗脱馏分(B1馏分),主要是四环以下无杂原子、无取代基或简单取 代基的芳香化合物;苯洗脱馏分(B2馏分),主要是单环的酚类化合物;甲醇洗脱馏分(B3馏分),主要是极性 化合物。实验结果表明,热解温度对生物油的产率和性质影响很大:生物油及沥青烯的产率在600-700℃范围 内达到最大值;随温度的升高,大分子化合物裂解成小分子化合物,含复杂取代基的化合物裂解生成含简单取 代基或者无取代基的化合物。实验结果也表明生物油中萘、甲基萘等主要来自于纤维素和半纤维素的热解,酚 类化合物主要源自于木质素的热解。

The properties and compositions of the corncob in a free-fall reactor were studied through bio-oil from fast pyrolysis of two typical biomasses： apricot stone and column chromatogaphic separation. The liquid product from the fast pyrolysis of the biomass was first separated into water, asphalt and bio-oil. The bio-oil was then injected into the silica gel colmnn and washed down by cyclohexane, benzene and methanol, respectively. GC-MS analysis showed that B1 contains mainly aromatics with up to four rings, B2 mainly aromatic with one ring and B3 mainly polar compounds. The pyrolysis temperature has a great effect on the yield and the property of the bio-oil. Both the maximum yields of bio-oil and that of asphalt were obtained under a certain temperature between 600-700℃. With temperature increasing from 500℃ to 800℃, greater molecules in the bio-oil are cracked into smaller ones, while the molecules with complex substitutions into those with simple substitutions or without. The result also showed that the chemicals such as naphthalene and methylnaphthalene are produced mainly from cellulose, and phenols from lignin.