CO2 utilization through high temperature CO2 enhanced sorption processes is a promising pathway to achieve widespread decarbonisation and to be successful, highly performing CO2 acceptors have to be developed. In this work, a fly ash derived lithium silicate material (Li-FA) was evaluated as CO2 sorbent under simulated biomass gasification conditions. The CO2 uptake tests were carried out using a high-pressure wire mesh apparatus between 380 °C and 700 °C, 15 bar and in presence of steam, H2, CO and CO2. The Li-FA sorbent was able to selectively adsorb CO2 with a maximum uptake of 4.2 mmol CO2/g at 700 °C under 4.5 bar CO2 (15 bar P total). The stability of the Li-FA CO2 sorbent was tested under more realistic exposition time in a 10-cycles experiment at 700 °C. Adsorption was very fast (138 mg CO2/g in average) requiring less than 20 s to achieve about 95 % of the total CO2 uptake of 3.2 mmol/g after 10 cycles and only 2 min to desorb the CO2 at 710 ° C and 15 bar. SEM/elemental mapping revealed that the good elemental dispersion was retained unchanged after 10 cycles. The kinetic analysis demonstrated that the sorption constants k1 and k2 were larger than those of similar high-temperature sorbents, which combined to their stability and CO2 uptake capacity offer promising application in CO2 sorption enhanced processes.
- CO capture
- Li-based sorbents
- Sorption-enhanced gasification
ASJC Scopus subject areas
- Chemical Engineering (miscellaneous)
- Waste Management and Disposal
- Process Chemistry and Technology