Study on thermochemical regeneration of exhausted activated carbon (EAC) and reusing it to regenerate exhausted triethylene glycol (ETEG)

Abstract

The regeneration of spent activated carbon (EAC), used in the adsorption of volatile organic compounds (VOCs) within triethylene glycol (TEG) dehydration units, is considered a more sustainable and economical alternative to disposal. This study aims to evaluate the thermo- chemical regeneration method by determining the optimal key parameters, such as the mass ratio (mKOH/mEAC), temperature, and regeneration time. The regenerated activated carbon (RAC) was also tested for its effectiveness in purifying spent glycol, using low- concentration alkaline chemical washing followed by thermal treatment. The best factors, including the mass ratio (mETEG/mRAC) and regeneration time, were identified. Experimental results showed that this combined approach significantly enhances the iodine number of the regenerated carbon and restores the physicochemical properties of TEG, making it a practical and economical option for reuse in the gas and petrochemical industries.