Perpustakaan Digital ITB

Mono ethylene glycol (MEG) has been used as a thermodynamic hydrate inhibitor in the gas industry. Due to its high usage, recoverability and environmental impact, MEG is regenerated instead of releasing to the environment. During the regeneration (distillation) process, MEG is exposed to higher temperatures in the reboiler to remove surplus water. When exposed to high temperatures, MEG thermal degradation process can occur due to dissociation to organic acids including glycolic, acetic and formic acids. A batch distillation system was utilised in total reflux mode at different reboiler temperatures retention times for up to 18 h in a span of 3 h and MEG concentrations of 80.8, 70.3, 63.1, 51.0 and 40.2 vol percentage (vol %) with corresponding reboiler testing temperatures of 118.0, 113.2, 108.8, 104.2 and 102.5 °C, respectively. The objective of this experimental work focuses on determining the MEG degradation products i.e. organic acids, accumulation in the MEG regeneration system. The degradation products were analysed using Ion Chromatography (IC) technique at the Curtin Corrosion Centre (CCC) laboratory, Perth, Western Australia. The experimental results indicate that there is an increasing trend of the MEG degradation products at higher boiling point temperatures for higher MEG concentrations in comparison to the lower MEG concentrations. Moreover, organic acids accumulation in the reboiler was evident at longer reboiler retention time durations of 18 h. The findings of this study conclude that it is preferable to operate the reboiler at lower MEG concentrations levels of 40.2 vol % and at reboiler retention time of 3 h to decrease the likelihood of the MEG degradation products. The percentage increase of the total organic acids at 40.2 vol % was found to be 27.7% as compared to 32.6% at 80.8 vol %. This study is beneficial to the oil and gas industry as it proposes the percentage amount of MEG to be used for hydrate inhibition in order to minimize the production of organic acids. High levels of organic acids accumulation in the regenerated lean lowers the efficiency of MEG thermodynamic inhibition performance.