Integrating post-combustion CO2 capture (PCC) into thermal power plants can reduce CO2 emissions but results in a significant decrease in net thermal efficiency. Optimizing PCC operating conditions, such as the ratio of the liquid flow rate to the gas flow rate (L/G) and stripper bottom temperature, reduces the net efficiency penalty. However, previous studies partially neglected the propagation effects of altered operating conditions on process performance, such as the effect of altered L/G and resultant change in fluid velocity on the heat transfer and pressure drop in the rich and lean solution heat exchanger. This study simulated amine-based PCC integrated into a natural gas combined cycle and explored optimal operating conditions comprehensively considering the propagation effects. The net efficiency penalty was minimized to 6.02%-pts. at a stripper bottom temperature of 130 °C and L/G of 0.82 for PCC operation with CO2 compression. Meanwhile, neglecting propagation effects of altered L/G led to underestimation of the efficiency penalty and erroneous determination of optimal operating conditions. The system evaluation methods suggested in this paper contribute to correctly optimizing PCC operating conditions and can be broadly applied to amine-based PCC studies employing novel amine solutions or process modifications.
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