Journal:  Energy Conversion and Management

Author: Dong-Wan Cho, Jechan Lee, Kwangsuk Yoon, Yong Sik Ok, Eilhann E. Kwon, Hocheol Song 

Abstract: 

Pyrolysis of spent coffee grounds (SCG) was performed to achieve the multiple purposes of waste disposal and energy recovery. This study placed great emphasis on pretreatment of SCG with FeCl₃ (Fe-SCG) and utilizing carbon dioxide (CO₂) as a reaction medium to enhance the generation of syngas while reducing condensable hydrocarbons (e.g., tar). For example, the principal effect of CO₂ was the enhanced generation of syngas via the CO₂-induced thermal cracking of volatile organic compounds (VOCs) and the reaction between CO₂ and VOCs, which resulted in subsequent reduction of tar. These identified effects on pyrolysis of SCG were more pronounced in pyrolysis of Fe-SCG, which could be attributable to the catalytic effect of the Fe mineral formed from phase transition of FeCl₃ during pyrolysis. The generation of CO in pyrolysis of Fe-SCG in the presence of CO₂ increased up to 8000% as compared to pyrolysis of SCG in N₂.

Keywords: Ferric chloride, Carbon dioxide, Gaseous products, Caffeine, Decomposition

DOI: https://doi.org/10.1016/j.enconman.2016.09.036