塔河常压渣油沥青质含硫官能团形态与其性质的关系研究

以塔河常压渣油为原料,分离正庚烷沥青质,并将正庚烷沥青质分成三个极性不同的亚组分。测定沥青质亚组分的平均偶极矩,利用¹H-NMR谱关联得到沥青质平均结构参数以分析沥青质亚组分缔合性质,采用X射线吸收近边结构谱(XANES)表征沥青质亚组分中含硫官能团形态,分析硫原子存在形态对沥青质性质的影响。结果表明,随着沥青质亚组分极性降低,H/C原子比增大;沥青质极性增加,缔合性增强;沥青质中还原态硫主要以噻吩硫形式存在,其次为硫醚;亚砜、砜和磺酸盐是主要的含氧硫化物。噻吩、砜和磺酸盐等官能团的存在对沥青质性质具有影响,但对沥青质极性及缔合性的影响不明显,杂原子硫不是影响沥青质极性和缔合性的主导因素。

Study on the relationship between sulfur functionalities and the characteristics of THAR asphaltene

The asphaltenes contain a lot of hetero-atoms, such as sulfur, nitrogen and oxygen, which play an important role on the polarity and association characteristics of asphaltenes. The n-heptane asphaltene was derived from the Tahe atmospheric residue (THAR). In addition, THAR n-heptane asphaltene was divided into three sub-fractions by difference of the polarities. The mean dipole moments of asphaltene sub-fractions were investigated. All of these asphaltene sub-fractions were measured by ¹H-NMR spectrometry. From the spectra, the average structural parameters could be obtained in order to analyze the association characteristics. The structures of sulfur functional groups were analyzed by X-ray absorption near edge structure (XANES) to study the influence of sulfur atoms upon the characterization of asphaltene. The results showed that as the polarity increased, the ratio of H/C atom decreased and association increased. For all sub-fractions samples, thiophene was the most dominant functional group of the reduced sulfur and followed by sulfide. The oxidized form of sulfur was present predominantly as sulphoxide, sulfone and sulfonate. Thiophene, sulfone and sulfonate influenced the characteristics of asphaltenes, but did not determine the polarity and association of asphaltenes. Thus, the sulphur atoms were not the decisive factors to determine the polarity and association of asphaltenes.