Techno-economic analysis of carbon dioxide separation for an innovative energy concept towards low-emission glass melting
The currently still high fossil energy demand is forcing the glass industry to search for innovative approaches for the reduction in CO₂ emissions and the integration of renewable energy sources. In this paper, a novel power-to-methane concept is presented and discussed for this purpose. A special focus is on methods for the required CO₂ capture from typical flue gases in the glass industry, which have hardly been explored to date. To close this research gap, process simulation models are developed to investigate post-combustion CO₂ capture by absorption processes, followed by a techno-economic evaluation. Due to reduced flue gas volume, the designed CO₂ capture plant is found to be much smaller (40 m³ absorber column volume) than absorption-based CO₂ separation processes for power plants (12,560 m³ absorber column volume). As there are many options for waste heat utilization in the glass industry, the waste heat required for CO₂ desorption can be generated in a particularly efficient and cost-effective way. The resulting CO² separation costs range between 41 and 42 EUR/t CO₂, depending on waste heat utilization for desorption. These costs are below the values of 50–65 EUR/t CO₂ for comparable industrial applications. Despite these promising economic results, there are still some technical restrictions in terms of solvent degradation due to the high oxygen content in flue gas compositions. The results of this study point towards parametric studies for approaching these issues, such as the use of secondary and tertiary amines as solvents, or the optimization of operating conditions such as stripper pressure for further cost reductions potential.