原油空气氧化前后多环芳烃组分的气相色谱-质谱分析

采用柱层析法对空气氧化前后的原油进行族组分分离,利用气相色谱-质谱(GC-MS)分离测定其芳香烃组分,分析多环芳烃组分的变化.结果表明,随着氧化过程的进行,烷基化多环芳烃占多环芳烃的含量从氧化前的71.5%增加到92.0%(175℃)和90.2%(225℃).轻质组分萘和菲的优势逐渐被重质组分艹屈取代.侧链少的多环芳烃比侧链多的更易氧化.氧化后,其他稠环化合物蒽、萤蒽、芘、苯并蒽含量降低,苯并萤蒽含量增加;苯并芘在175℃氧化后含量降低,而在225℃氧化后含量增加.与此同时,175℃氧化后生成了原油所不含有的三芳甾烃、联苯和苯并呋喃.

Analysis of Polycyclic Aromatic Hydrocarbons in Crude Oil before and after Air Injection by Gas Chromatography-Mass Spectrometry

Crude oils before and after air-injection-induced oxidation at relatively low temperature were separated by means of column chromatography.The polycyclic aromatic hydrocarbons（PAHs） in the crude oils were analyzed by using gas chromatography combined with mass spectrometry（GC-MS） so as to reveal the variation of PAHs in air injection technique.It was found that the content of alkylated PAHs increased from 71.5%（before oxidation） to 92.0%（being oxidized at 175 ℃） and 90.2%（being oxidized at 225 ℃）.The predominance of light component naphthalene and phenanthrene shifted to heavy component chrysene,with components of less side-chain more susceptible to oxidation.At the same time,oxidation led to decrease of the content of anthracene,fluoranthene,pyrene and benzanthracene,and increase of the content of benzofluoranthene.Moreover,the content of benzopyrene decreased after oxidation at 175 ℃ and increased after oxidation at 225 ℃.Particularly,tri-aromatic steroid,diphenyl and benzofuran,absent in crude oil,were generated after oxidation at 175 ℃.