For CO2 sorbents, a fast sorption rate is as important as the sorption capacity in order to enable efficient CO2 capture in the treatment of large amounts of emission gas, where the contact time between the sorbent and gas is limited. A facile and environmentally benign method of fabricating advanced sorbents with fast CO2 sorption for pre-combustion capture was developed by incorporating CaCO3 into triple salt-promoted MgO sorbents (LiNO3, NaNO3, and Na2CO3) using salt-controllable coprecipitation. The incorporation of Ca into the salt-promoted MgO (MgCa) was effective for controlling the lattice parameter, textural properties, and basicity. The salt-promoted MgCa sorbents had a bi-disperse pore distribution with different range, which contributed to the fast sorption. When 5 mol.% of Ca was doped into the triple salt-promoted MgO, the CO2 sorption capacity within 10 min was significantly improved (from 6 wt% (MgO) to 43 wt% (MgCa-5%)) at 325 °C. For CO2 sorption for 10 min at 325 °C and N2 regeneration for 5 min at 400 °C, the working capacity of MgCa-5% was approximately 30 wt% at the 30 th cycle. Under the same rapid cycling conditions, the sorption capacity was 12 wt% when a wet CO2 mixture (29 vol% CO2, 3 vol% H2O, and balance N2) and pure CO2 was used for sorption and regeneration, respectively. When the regeneration gas contained water vapour, the cyclic sorption capacity decreased to 1–2 wt%. The MgCa sorbents prepared via salt-controllable coprecipitation exhibited high working capacities during the rapid cyclic temperature swing operation at intermediate temperature.
All Science Journal Classification (ASJC) codes
- Environmental Chemistry
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering