Lithium orthosilicate for CO2 capture with high regeneration capacity: Kinetic study and modeling of carbonation and decarbonation reactions

Abstract

One of the most promising techniques for CO2 capture at high temperatures consists in its separation by the carbonation reaction with an inorganic solid. Lithium orthosilicate (Li4SiO4) is considered one potential material due to its high capture capacity and thermal stability. In this study, the kinetics of carbonation and decarbonation of Li4SiO4 was evaluated at atmospheric pressure, isothermal and non-isothermal conditions and in cycling experiments. According to the non-isothermal test, carbonation occurs within 500–715°C and decarbonation above it. Isothermal tests showed that the reaction rates increased with increasing temperature and at high temperatures it was possible to capture up to 35wt% CO2. Kinetics of both carbonation and decarbonation was adequately described by the shrinking core model. The Li4SiO4 presented an excellent durability comparing to other materials for CO2 capture, with an activity decay of 20% after 48 cycles.