CO2 capture with a novel solid fluidizable sorbent: Thermodynamics and Temperature Programmed Carbonation–Decarbonation

• We prepared a new and stable CO2 sorbent based on lithium orthosilicate.
• We develop a CO2 capture thermodynamic analysis for various fluidizable sorbents.
• We develop TPC and TPDC using a temperature programmed fixed bed unit.
• We develop TPC–TPDC runs using calcium carbonate and lithium orthosilicate.
• We are able to predict sorbent regeneration and temperature inversion points.

This study investigates several sorbents for CO2 capture with emphasis on the development of a novel lithium orthosilicate based sorbent. Thermodynamic analysis is considered to predict sorbent regeneration conditions and thermal levels where sorbent kinetics change from CO2 absorption to CO2 desorption. Temperature Programmed Carbonation (TPC) and Temperature Programmed Decarbonation (TPDC) are developed using a temperature programmed fixed bed unit. Sorbents are kept in contact with a gas stream containing a 10% CO2 mole fraction, and are subjected to a 5 °C/min temperature ramp. 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.

Consecutive CO2 absorption–desorption with the new fluidizable Li4SiO4. Temperature ramp: 5 °C/min; Input Gas composition: 10 vol% CO2 in helium; flow rate: 50 mL/min.Figure optionsDownload as PowerPoint slide