Techno-economic assessment of carbon capture and utilization concepts for a CO2 emission-free glass production

Kurzfassung

The container glassEuropean industry is challenged by the goal to be “fit for 55”, and even more by complete climate neutrality until 2045/50 and requires individual solutions for each sector. For example, CO2 emissions of the glass industry (around 22 Mio t per year in Europe) originate primarily from two sources, i.e., fuel-related emissions, and process-related emissions caused by carbonatic batch ingredients. Although, fuel-related emissions can be avoided by, e.g., the implementation of hydrogen combustion or all-electric melting (AEM), these approaches do not address process-related emissions. Moreover, the knowledge on hydrogen-based glass production is still limited, with open questions regarding refractive materials and redox behavior of the melt. AEM, on the other hand, is limited to comparably small tonnages (less than 250 t saleable glass per day) and cullet contents in the batch below 60 %. Additionally, since the redox state of AEM glass is difficult to control, this process is unsuitable for redox-sensitive amber coloring. The process-related CO2 emissions could theoretically be avoided by replacing carbonatic batch ingredient with, e.g., hydroxides. However, the production of hydroxides requires often geological carbonates as raw materials (lime, dolomite), or is very cost- and energy-intensive (NaOH, via chlor-alkali process). In contrast, implementation of Carbon Capture and Utilization (CCU) with e-fuel synthesis via electrolytic produced zed hydrogen addresses both emissions sources without constraining the glass production. Here, we convert the CO2-rich flue gas stream (above 95% dry gas composition for oxy-fuel combustion) with on-site generated hydrogen into a storable fuel. Finally, we close the CCU cycle, as we use the synthesized e-fuel to feed the combustion for glass melting heat. With this, we generate a saleable product from the process-related CO2 surplus and at the same time avoid all CO2 emissions. To assess the viability of CCU cycles in the glass production, we perform a techno-economic analysis on a simulated glass production process with integrated CO2 recovery and subsequent fuel synthesis was performed. We evaluate the technological and economic advantages of CCU cycles for several state-of-the-art technology chains and analyze the influence of different electricity price scenarios on the production cost. The most suitable technologies, including gas cleaning, fuel synthesis and hydrogen production, are converted into a Python model and simulated in Aspen Plus®. Subsequently, the techno-economic performance is estimated with the DLR in-house tool TEPET. As regenerative grid electricity prices significantly fluctuate over time, we additionally develop an algorithm was developed to optimize the plant’s purchased electricity pricepurchasing, using trading at the German day-ahead market. With a combination of over-dimensioning the electrolyzer and variation of ying the hydrogen storage capacity, we lower the effective overall electricity costs can be minimized by avoiding periods of high electricity prices. With these results, we enable aAn objective and transparent comparison of multiple plant layouts, and thus, can help to select the most suitable solution for the each glass industry production site in different scenarios.