Introduction of Li4SiO4 for carbon capture

“Li₄SiO₄, with a variety of applications [12,13], has better application potential, owing to its higher CO₂ sorption capacity, cyclic stability than LiFeO₂, Li₂CuO₂, and Li₈SiO₆, and lower cost than that of Li₂ZrO₃ [9]. Additionally, the regeneration temperature of Li₄SiO₄ material is much lower compared with the calcium-based CO₂ sorbents, indicating that lower energy consumption is required for the regeneration. Li₄SiO₄ material is usually obtained by the solid-state reaction method with Li₂CO₃ and SiO₂ at high temperature, which is shown in Equation (1) [14]:

The basic reversible reaction for CO₂ sorption by Li₄SiO₄ material follows Equation (2), and the process is shown in Figure 1. In the absorption reactor, CO₂ in flue gas from fossil fuel-fired power plants or syngas from hydrogen plants based on sorption-enhanced reforming is absorbed by Li₄SiO₄ at 500 to 600 °C, thus the gas, almost free of CO₂, is exhausted from the reactor. The generated Li₂SiO₃ and Li₂CO₃ are transported to the regeneration reactor, where Li₄SiO₄ is regenerated at temperatures higher than 700 °C and sent to the absorption reactor for the next CO₂ absorption cycle, and CO₂-rich gas can be obtained in the regeneration reactor.

Li4SiO4+CO2↔Li2SiO3+Li2CO3   (2)”

“Figure 1. Application of Li₄SiO₄ material for CO₂ absorption for fossil fuel-fired power plants or hydrogen plants based on sorption-enhanced reforming.”