Study of propylene glycol thermal degradation by batch distillation process and analysis using ion chromatography

Abstract

Application of regenerated thermodynamic inhibitor (THI) is a cost-effective way of hydrate inhibition in oil industries. There have been literature reports for application of regenerated THI monoethylene glycol (MEG) in order to keep the process economical and also to avoid releasing the used MEG to the environment in order to reduce its impact. In our previous studies, thermodynamic gas hydrate equilibrium curves were established for pure propylene glycol. So, in continuation to previous work, thermal degradation of propylene glycol is studied in this research to be applicable for gas hydrate inhibition as regenerated product. A laboratory batch distillation setup is utilized for conducting thermal degradation of propylene glycol (40 and 80 wt%). Degraded products were collected at different time intervals to identify generated organic acids. Major degradation product observed was lactic acid and other generated acids include formic, acetic and pyruvic acid. Results showed increase of degradation product concentration with increasing retention time and higher propylene glycol concentration. The degradation characteristics studied in the research work will be helpful to identify the parameters affecting the degraded propylene glycol efficiency to be tested as gas hydrate inhibitor in our future research work.

Keywords:

• Batch distillation
• organic acid
• propylene glycol
• retention time
• thermal degradation

Acknowledgment

The authors would like to acknowledge Curtin University Corrosion Centre for providing the laboratory facilities and the contribution of Curtin International Postgraduate Research Scholarship (CIPRS) in supporting this research.

Disclosure statement

The authors declare that there is no conflict of interest.