Long Term Durability of Dolomite-Derived MgO-Based Sorbent for CO2 Capture in IGCC

New generation of coal power plants such as Integrated Gasification Combined Cycle (IGCC)

reduces the emissions of CO2

efficiency losses, it is desirable to remove CO2 in the temperature range of 300° to 450°C,

which makes regenerable MgO-based sorbents ideal for such operations. The sorbents have

high reactivity and good capacity toward CO2 absorption in the temperature range of 300–450 C

at 20 atm. and can be easily regenerated at the temperature range of 500–550 C. The effect of

cycling on CO2 capture capacity of MgO-based sorbent prepared from natural dolomite was

experimentally investigated in this work. The rates of carbonation and regeneration reactions

were studied. Series of carbonation/regeneration cycles (up to 24) have been carried out in a

dispersed bed reactor to determine the effect of various variables on long term durability of the

sorbent. The gradual loss of CO2 sorption capacity appears to be mainly due to loss potassium

(a carbonation reaction promoter) in the cyclic process. Durability of the sorbents improves in

the presence of steam, which is likely due to the favorable changes in the pore structure of the

sorbents. A variable diffusivity shrinking core model has been used to fit the experimental data

of the sorbent carbonation and regeneration in the cyclic process with excellent accuracy.

per unit of power generated. In IGCC processes, to avoid