快速蒸馏法及其在原油酸值分布规律研究中的应用

原油和馏分的酸值(TAN)是反映其加工过程中腐蚀性的重要指标。传统的实沸点蒸馏(TBP)方法未考虑石油酸在原油蒸馏过程中的分解，得到的馏分酸值严重偏低，影响了对馏分腐蚀性的判断以及相应防腐措施的制订。为此开发了一种原油快速蒸馏(RD)仪，采用短分馏柱、高真空度、高蒸馏速率对原油进行分段蒸馏切割，有效避免了原油中石油酸的分解，使各馏分酸值的加权值达到了原油酸值的90%以上。在此基础上，研究了几种典型高酸原油酸值的分布规律，发现原油可馏出部分的酸值基本上都是随着沸点的升高而增高。另外，通过傅里叶变换离子回旋共振质谱(FT-ICR MS)分析表明，实沸点蒸馏过程中酸值降低的主要原因是大分子石油酸的分解，而与石油酸的类型相关性较小。

Rapid Distillation Method and Its Application in the Study of the Distribution Law of the Total Acid Number of Crude Oil

The total acid number (TAN) of crude oil and distillates is deemed as an important indicator to reflect their corrosivity during processing. The traditional true boiling point distillation (TBP) method does not take into account the decomposition of petroleum acid in the process of crude oil distillation, as a result of which the acid number of the distillates is extremely low, affecting the determination of the corrosivity of distillates and the formulation of corresponding anti-corrosion measures. Therefore, a rapid distillation (RD) apparatus for crude oil was developed for segmented distillation cuts using short fractional column, high vacuum degree and high distilling rate, which can effectively avoid the decomposition of the petroleum acid in crude oil, and make the weighted total acid number of each distillate reach above 90% of the total acid number of crude oil. On this basis, a study is performed on the distribution law for the total acid number of some typical high-acid crude oils, and it is found that the total acid number of the distillable parts in crude oils basically increases as boiling point rises. In addition, the analysis of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) shows that the main reason for the decrease of total acid number in the process of TBP distillation lies in the decomposition of macromolecular petroleum acid, which is less correlated with the type of petroleum acid.