中国炼油与石油化工 ›› 2014, Vol. 16 ›› Issue (01): 8-12.

• Scientific Research • 上一篇    下一篇

实沸点蒸馏前后高酸重质原油的石油酸分布表征

刘颖荣,章群丹,王威,刘泽龙,祝馨怡,田松柏   

  1. 中国石化石油化工科学研究院
  • 收稿日期:2013-12-12 修回日期:2013-12-27 出版日期:2014-03-30 发布日期:2014-03-30
  • 通讯作者: 刘颖荣 E-mail:liuyr.ripp@sinopec.com
  • 基金资助:
    973 国家重点基础研究发展规划973项目:石油资源的分子鉴别和转化规律认识

Changes of Petroleum Acid Distribution Characterized by FT-ICR MS in Heavy Acidic Crude Oil after True Boiling Point Distillation

Liu Yingrong,Zhang Qundan,Wang Wei,Liu Zelong,Zhu Xinyi,Tian Songbai   

  1. Research Institute of Petroleum Processing, SINOPEC
  • Received:2013-12-12 Revised:2013-12-27 Online:2014-03-30 Published:2014-03-30
  • Contact: Liu Yingrong E-mail:liuyr.ripp@sinopec.com

摘要: 实沸点蒸馏是原油评价的重要手段,但实验发现高酸重质原油经实沸点蒸馏后酸值明显降低,表明原油中的石油酸发生了热分解。本文采用FTICR MS 对实沸点蒸馏前后高酸原油的羧酸分布进行了表征。结果表明经过实沸点蒸馏后,尽管石油酸的总体响应峰强明显降低,但其羧酸类型分布与原油接近,这说明各类型的石油酸反应行为接近;但蒸馏前后两者的石油酸碳数分布相差很大,在蒸馏之后样品中,所有类型>C35的大分子的石油酸峰强均明显降低;尤其是碳数>60的石油酸峰强几乎检测不到;这说明存在于重馏分中的大分子石油酸由于受热时间长,分解发生的更多。实验表明酸值降低主要来源于石油酸尤其是大分子石油酸的热分解。建议采用更低压力蒸馏或快速蒸馏来避免该现象。

关键词: 实沸点蒸馏, ESI, FT-ICR MS, 石油酸, 高酸原油

Abstract: The carboxylic acid molecular transformations of heavy acid SL crude before and after true boiling point distillation are examined by ultrahigh-resolution negative-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The acid class (heteroatom number), type (z numbers) and carbon number distributions were positively characterized. It was found the total acid number (TAN) of SL crude decreased after true boiling point distillation, and the abundance of O2 class in mass spectrum was also found to be reduced from 67.6% to 34.5% in SL TBP mixed crude in MS spectrum, suggesting the potential carboxylic acid decomposition. However, it was interesting that both oils’ carboxylic acid type distributions were almost the same although their relative abundance of SL TBP mixed crude turned to be much lower, indicative of that various petroleum carboxylic acid types have the similar thermal decomposition reaction behavior. Furthermore, for each O2 type in SL TBP mixed crude, the abundance of carboxylic acid with carbon number higher than 35 was reduced greatly, especially for those with carbon number higher than 60, which mass peaks were nearly totally removed, indicating the large carboxylic acid molecules in heavy fractions decomposed much more because of longer heating time in the true boiling point distillation process. As a result, the reducing of TAN may be due to the thermal decomposition of carboxylic acids especially those with high carbon number, suggesting quick distillation or much lower pressure is suggested to avoid the thermal decomposition.

Key words: true boiling point distillation, ESI, FT-ICR MS, carboxylic acid, acidic crude, Total Acid Number