Optimization of High-Temperature CO[sub.2] Capture by Lithium Orthosilicate-Based Sorbents Using Response Surface Methodology

• Published in: Atmosphere 2024-08, Vol.15 (8)
• Main Authors: Stefanelli, Eleonora, Francalanci, Flavio, Vitolo, Sandra, Puccini, Monica
• Format: Article
• Language: English
• Subjects: Carbon sequestration; Comparative analysis; Environmental aspects; Lithium compounds; Silicates; Sorbents
• ISSN: 2073-4433; 2073-4433
• DOI: 10.3390/atmos15080908

The major challenge in the current context of the rising world energy demand is to limit the global temperature increase for mitigating climate change. This goal requires a large reduction of CO[sub.2] emissions, mainly produced by power generation and industrial processes using fossil fuels. In this study, a novel methodology for K[sub.2] CO[sub.3] -doped Li[sub.4] SiO[sub.4] sorbents production for CO[sub.2] capture at high temperatures was adopted based on the Design of Experiments (DoE). This innovative approach systematically tested different synthesis (temperature and K[sub.2] CO[sub.3] content) and adsorption conditions (sorption temperature and CO[sub.2] concentration), allowing for the assessment of individual and interactive effects of process parameters. The Response Surface Methodology (RSM) was employed to obtain non-linear predictive models of CO[sub.2] uptake and Li[sub.4] SiO[sub.4] conversion. The results of RSM analysis evidenced a maximum adsorption capacity of 196.4 mg/g for a sorbent produced at 600 °C and with 36.9 wt% of K[sub.2] CO[sub.3] , tested at 500 °C and 4 vol% of CO[sub.2] . Whereas at 50 vol% of CO[sub.2] , the best uptake of 295.6 mg/g was obtained with a sorbent synthesized at 600 °C, containing less K[sub.2] CO[sub.3] (17.1 wt%) and tested at a higher temperature (662 °C). These findings demonstrate that K[sub.2] CO[sub.3] -doped Li[sub.4] SiO[sub.4] sorbents can be tailored to maximize CO[sub.2] capture under various operating conditions, making them suitable for use in industrial processes.