Particle design and evaluation of dry CO2CO2 recovery sorbent with a liquid holding capability

For CO2CO2 capture at high-temperature/high CO2CO2 partial pressure conditions a new dry CO2CO2 removal sorbent was developed based on lithium silicate with additives to accelerate CO2CO2 sorption. To avoid adhesion and defluidization associated with the formation of the liquid carbonate phase in the temperature range of 500–600∘C, the sorbent particles were designed whereby the granulated lithium silicate core was coated with a layer of coarse alumina particles. This prevents the liquid lithium carbonate from wetting the sorbent surface. Several different types of sorbents were manufactured by granulation and coating with different ceramic sol binders and different prescriptions in a tumbling fluidized bed. Minimum fluidization velocity, fluidizing behavior and adsorption/desorption properties of the sorbent particles were determined in a laboratory scale fluidized bed reactor (i.d., 0.03 m) in the temperature range up to 1073 K. During a repeated cyclic adsorption/desorption, a gradual decrease in both the overall conversion and maximum adsorption capacity took place. Nevertheless, the performance obtained for the sorbent manufactured with alumina sol was found to be the most successful one characterized by no defluidization and a high adsorption capacity of 50% in conversion (10 wt% including the coat layer) over 60 cycles.