Closed CO2 cycles in the glass production: A techno- economic evaluation

Abstract

In this work, we examine the feasibility and costs of implementing CCU processes into a generic glass production, an industry responsible for the emission of about 95 million tonnes of CO2 per year. For this, we propose and analyze a process-chain to capture CO2 from the flue gas of oxy-fuel glass furnaces and further convert it into synthetic methane for its reinjection into the furnace. The process-chain is simulated using Aspen Plus® and assessed techno-economically to estimate the net production- and investment costs. We assumed the conditions of the German electricity day-ahead-market for the year 2020 to include the volatility of green energy production. Since the electricity price is crucial component of the production costs, the average purchased price was heuristically optimized based on the hydrogen production- (full load hours of the electrolyzer) and storage capacity of the plant. The influence of the hydrogen production- and storage capacity on the net production costs is exposed and the ideal result for the year 2020 is identified. Finally, the opportunities and challenges to decarbonize the glass production via CCU are presented, together with the associated costs for the process-chain.