Li4SiO4-Based Novel Solid Fluidizable Sorbent for CO2 Capture:

This study investigates the cyclic use of several sorbents for CO2 capture and comparative study of thermodynamic analysis to predict sorbent regeneration conditions and thermal levels where sorbent kinetics change from CO2 absorption to CO2 desorption. It is expected cycling processes with CO2 capture and sorbent regeneration and alternative sorbents (e.g. lithium ortho-silicate based novel sorbent) could lead to significant energy savings with limited sorbent sintering. On this basis CO2 absorption and desorption were quantified at various temperatures and CO2 partial pressures. Temperature Programmed Carbonation (TPC) and Temperature Programmed Decarbonation (TPDC) were developed using temperature programmed equipment at CREC-UWO laboratories employing several sorbents subjected to a 5°C/min temperature ramp and with a gas stream containing a 10% CO2 mole fraction. Calcium carbonate , lithium orthosilicate and a novel lithium orthosilicate modified sorbent are considered for these runs. TPC-TPDC runs confirm thermodynamic predictions for thermal inversion points. Furthermore , TPD-TPDC runs show that the novel lithium orthosilicate based sorbent provides a very stable and increased CO2 sorption capacity over 10 absorption-regeneration cycles , while calcium carbonate displays a reduced CO2 sorption capacity with cyclic operation. This fluidizable novel sorbent can significantly contribute towards CO2 removal from flue gases emitted by power plants. The thermodynamic and TPC-TPDC analysis of the present study also provides a conceptual design from developing CO2 capturing processes with alternative sorbents such as lithium ortho-silicate based sorbent.