Carbon dioxide utilization based on exergoenvironmental sustainability assessment: A case study of CO2 hydrogenation to methanol

• Published in: Energy (Oxford) 2023-06, Vol.273, p.127219, Article 127219
• Main Authors: Huang, Yue, Zhu, Lin, He, Yangdong, Wang, Yuan, Hao, Qiang, Zhu, Yifei
• Format: Article
• Language: English
• Subjects: Carbon utilization; Exergoenvironmental analysis; Exergy analysis; Methanol
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2023.127219

Recently, adopting H2 to convert CO2 into value-added products to reduce greenhouse gas emissions or dependence on fossil fuels has been widely investigated. For this purpose, two production processes of methanol are investigated: direct hydrogenation of CO2 to methanol (DHCM) and reverse water gas conversion of CO2 and H2 to methanol (GS-HCM). In this study, comprehensive thermodynamic and exergoenvironmental assessments are carried out to identify which CO2 utilization technologies are appropriate for future sustainable development. The results indicated that the exergy efficiency of the DHCM method is 2.49% higher than that of the GS-HCM process, showing obvious advantages in terms of energy utilization. However, from an exergoenvironmental perspective, the GS-HCM system is regarded to be more promising than the DHCM system because the environmental impact of generated methanol is 38.49 mPt/kg, lower than the DHCM method. Besides, the environmental impact caused by exergy destruction constituted the major environmental impact of both systems. In addition, the exergy and exergoenvironmental performance were introduced to disclose the formation of environmental impact from the component level in detail, and optimization measures were proposed to improve the efficiency and environmental benefits of the main components. •Two different carbon utilization processes to produce methanol are proposed.•A comprehensive evaluation of thermodynamic and exergoenvironmental are implemented.•Exergy efficiency of the DHCM method is 2.49% higher than that of the GS-HCM system.•Environmental benefit of GS-HCM system is more superior compared with DHCM system.