固态13C-NMR法表征渣油沥青质的结构组成

以长庆常压渣油、胜利减压渣油和加拿大减压渣油为原料，研究了正庚烷沥青质的结构及组成，根据固态13C NMR分析结果，计算了沥青质分子的平均结构单元参数，并模拟出了沥青质的结构单元模型。结果表明，沥青质分子由4个左右的结构单元组成，每个结构单元包括5～7个缩合芳香环。沥青质中的饱和碳以环烷碳为主，并包含少量的短烷基侧链，沥青质的n(HS)/n(CS)在16左右。对于平均相对分子质量较大、具有较短烷基侧链和较少取代基的沥青质分子，由核磁共振氢谱计算其结构参数时，采用重油计算过程的假设--芳香环烷基侧链上α位及β位和β位以远的氢/碳比为2(x=y=2)是不合理的，可能会导致计算结果与沥青质的真实结构存在较大的误差。

Structure and composition characterization of asphaltene by soli-sate 13C-NMR

The structure and composition of n heptane asphaltenes from Changqing atmospheric residue, Shengli vacuum residue and Canadian vacuum residue were studied with using solid state 13C NMR. Based on solid state 13C NMR characterization results, the average structure unit parameters of asphaltenes were calculated, and asphaltene structure unit model was simulated. Experimental and calculation results indicate that asphaltene molecules consist of about 4 structure units, each containing 5 to 7 ploy aromatic rings. For saturated carbons in asphaltenes, there are mainly naphthenic carbons with a few short alkyl side chains. For asphaltenes with large average relative molecular mass, short alkyl side chains and less substituents, n(HS)/n(CS) of asphaltene is about 16. This indicates that there is a large error in the calculation of asphaltene structure parameters by following heavy oil calculation procedures, which assumes that n(H)/n(C) of α, β and other alkyl side chains in aromatic rings is 2.