渤海稠油界面活性组分的多级分离与分子组成

Multistage separation and molecular composition of interfacial active materials in Bohai heavy oil

串联不同含水率φ硅胶柱将渤海原油分离成φ1-Ⅱ、φ2-Ⅱ、φ2-Ⅰ三个组分,界面活性顺序为φ1-Ⅱ>φ2-Ⅱ>φ2-Ⅰ,其中改性硅胶含水率越高,分离得到的活性组分界面活性越强,采用负离子电喷雾技术(ESI)结合高分辨傅里叶变换离子回旋共振质谱仪(FT-ICR MS)研究原油组分的分子组成。结果表明:原油组分中含有多种不同杂原子类型化合物,包括N_(1)、N_(1)O_(1)、N_(1)O_(2)、N_(1)O_(3)、N_(1)O_(4)、N_(2)、O_(1)、O_(1)S_(1)、O_(2)、O_(2)S_(1)、O_(3)、O_(3)S_(1)、O_(4)、O_(4)S_(1)、O_(4)、O_(5)S_(1)等,其中含杂原子S的氧化物(O_(1)~5 S_(1))、含杂原子N的氧化程度高的化合物(N_(1)O_(3~4))及O_(5)类化合物界面活性最强,主要存在于φ1-Ⅱ中,其次是O_(2~4)类化合物及杂原子N氧化程度低的(N_(1)O_(1~2))氧化物,界面活性最弱的是N_(1~2)、O_(1)类化合物,主要存在于φ2-Ⅰ中;O_(2~4)、N_(1)O_(1~2)类化合物存在于3个组分中,其分子组成存在明显差异,活性最强的组分φ1-Ⅱ中O_(2~4)、N_(1)O_(1)类化合物的平均碳数最小且等效双键数(DBE)较小;而活性组分φ2-Ⅱ中O_(2~4)、N_(1)O_(1)类化合物芳香化程度较高,结构类似沥青质组分;对于原油组分中N_(1)O_(2)类化合物,其平均碳数和DBE随着组分界面活性增强而减小。

Bohai heavy oil was separated into three fractions ofφ1-Ⅱ,φ2-Ⅰandφ2-Ⅱby hydrated silica gel column with different water content.The interfacial activity of these fractions decreased in the following order:φ1-Ⅱ,φ2-Ⅱ,φ2-Ⅰ.The interfacial activity of isolated interfacial material is in accordance with the amount of water loaded onto the silica gel.Molecular composition of oil components were characterized by negative ion electrospray ionization(ESI)Fourier transform ion cyclotron resonance(FT-ICR)mass spectrometry(MS).It is found that the composition of heteroatoms in oil components is relatively complex.Class species such as N_(1),N_(1)O_(1),N_(1)O_(2),N_(1)O_(3),N_(1)O_(4),N_(2),O_(1),O_(1)S_(1),O_(2),O_(2)S_(1),O_(3),O_(3)S_(1),O_(4),O_(4)S_(1),O_(4),O_(5)S_(1) are identified with high resolution FT-ICR MS.The most interface-active species within Bohai heavy oil are the O_(1~5)S_(1),N_(1)O_(3)~4 and O_(5) species,mainly inφ1-Ⅱ;the next are the lower order O_(2~4) and N_(1)O_(1~2)species,and the weakest are N_(1)~2 and O_(1) species,mainly inφ2-Ⅰ.The O_(2~4) and N_(1)O_(1~2) species exist three oil fractions and show significant differences.The O_(2~4) and N_(1)O_(1) species with owest carbon number/lower DBE in most interface-active compoundsφ1-Ⅱ.While inφ2-Ⅱ,the O_(2~4) and N_(1)O_(1) species have lower carbon number ranges but highest DBE,which present similiar characteristic of asphaltenic species.However for N_(1)O_(2) species in three oil fractions,the carbon number and DBE decrease as the interfacial activity increases.