Study of the NaOH(s)–CO2(g) reaction creating value for industry: green natrite production, energy, and its potential in different sustainable scenarios

Abstract

In this work, we present a comprehensive analysis of a solid-based NaOH technology for CO₂ capture. After CO₂ capture, high purity γ-Na₂CO₃ synthetic natrite is formed as demonstrated through exhaustive characterization using several chemical techniques (XRD, XPS, ¹³C and ²³Na MAS-NMR, ATR-FTIR, and TGA), and additionally a DFTB computational analysis was performed. The use of solid NaOH could offer some technical advantages such as high exothermicity (3445 MJ per tCO₂) and the production of high value carbonates (natrite). Furthermore, we consider either carbonate commercialization or regeneration of NaOH in our model. This novel technology has important advantages over currently available technologies regarding efficiency in capture and potential for heat exploitation. Additionally, environmental analysis reveals a negative LCA index (life cycle assessment index) for flue gas capture and the lowest operative costs for CO₂ capture. Two sustainable models are proposed that not only focus on CO₂ capture, but also on the sustainability of time. One model is based on sale of natrite, because the projections in the global market for carbonates will continue to increase, due to their non-traditional applications, e.g., in molten carbonate fuel cells, batteries and other technologies for generation and storage of energy. The second model considered NaOH-raw material regeneration, and pure CO₂ released can be used in obtaining of synthetic fuel, food packaging, and other industrial chemical procedures, and in this respect the current global demand for CO₂ is around 140 Mt per year.