Continuous extraction of naphthenic acid from low-grade oil using 1,6-hexanediol in an ammonia solution

Sung Shin Kang, Tae Hyun Kim, Dong Woo Cho, Jong Nam Kim, Jeong Won Kang

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


The efficient use of low-quality crude oil is one short-term solution to overcoming the imminent energy crisis due to the depletion of fossil resources. Several methods have been developed to upgrade low-quality oil, the most important part of which is the removal of acidic components. High-acid crudes can be converted to lower-acid crudes using various methods based on physical and chemical principles. In this contribution, we suggest an efficient and economical method based on liquid–liquid extraction. The candidate solvent was screened from a thermodynamic analysis in a previous study, and the additives and process conditions were adjusted according to experimental results. As the final solvent choice, 1,6-hexanediol in an aqueous ammonia solution showed the best performance with the minimal amount of solvent (weight fraction of 0.6). Experiments showed that the proposed solvent can be used to treat real crude oil used in the industry. A continuous operation scheme was suggested with solvent regeneration and recycling combined with separation of the acidic residue. The results showed that the proposed extraction process can reduce 85% of the acidic component in high-acid crudes and that repeated use of the solvent is possible.

Original languageEnglish
Article number126008
Publication statusPublished - 2023 Jan 15

Bibliographical note

Funding Information:
This work was supported by National Research Foundation of Korea (NRF) grants funded by the Korean government (MSIT) [grant numbers NRF-2021R1A5A6002853 and 2019M3E6A10648762.

Publisher Copyright:
© 2022 Elsevier Ltd


  • 1,6-hexanediol
  • Acidity reduction
  • Ammonia solution
  • High-acid crude
  • Naphthenic acid
  • Oil upgrading

ASJC Scopus subject areas

  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Organic Chemistry


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