Evaluation of post combustion CO2 capture by a solid sorbent with process modeling using experimental CO2 and H2O adsorption characteristics
article
System modeling was used to evaluate post combustion CO2 capture in a simulated pulverized coal (PC) and natural gas combined cycle (NGCC) power plant using a solid sorbent. Both CO2 and H2O adsorption play a role in the energy assessment. No adsorption characteristics of a polyethyleneimine on silica sorbent were available from literature, necessitating for experimental determination. The measured CO2 and water sorption enthalpies, ?hCO2 = 91 ± 5 kJ/mol and ?hH2O = 60 ± 8 kJ/mol, were implemented in the flow sheeting model. The experimental determination of CO2 and H2O adsorption revealed that co-adsorption of water cannot be neglected in process evaluations. The break-down of the contributions to the regeneration heat was calculated for the PC, NGCC and conventional mono-ethanolamine (MEA) cases. The PC case capture penalty is lower than that the NGCC case, primarily as a result of a higher CO2 cyclic capacity. The total regeneration heat for a non-optimized sorbent was calculated to be similar to the MEA case, about 3.9 GJ/ton CO2 captured. Solid sorption systems hold the promise to be energetically superior to MEA: a 2-fold increased CO2 adsorption capacity only (to 4.4 mmol/g) compared to the non-optimized sorbent used in this study yields a regeneration heat demand of 3.3 GJ/ton, even when accompanied by a similar increase in H2O adsorption capacity.
TNO Identifier
849976
Publisher
ECN
Collation
60 p.
Place of publication
Petten
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