Post-combustion CO2 capture from a natural gas combined cycle power plant using activated carbon adsorption

As fossil fuel power plants have emitted significant quantity of carbon dioxide (CO 2 ) into the atmosphere which aggravates climate change, capturing and storing such emissions is key to mitigate the issue. An adsorption system based on a physical adsorbent i.e. activated carbon is first assessed to capture CO 2 emissions from a natural gas combined cycle. Then a subcritical sequential supplementary firing combined cycle with CO 2 capture is used to analyse the effect of CO 2 concentration. Analyses are carried out in terms of power loss and thermal efficiency. To evaluate the advantages of post-combustion CO 2 capture using activated carbon, results are compared with systems using a commercial absorbent, i.e. monoethanolamine and a chemical adsorbent i.e. polyethyleneimine/silica. The net efficiency of natural gas combined cycle using activated carbon increases slightly from 50.8% to 51.1% due to the lower regeneration temperature at 358 K. The performance of the system using PEI/silica is almost the same as that using activated carbon at 368 K. Although the thermal energy required to regenerate the activated carbon is relatively high, a significant improvement of net efficiency is observed with increased partial pressure. Economic analysis indicates that the systems using activated carbon is a competitive alternative for CO 2 capture. It is concluded activated carbon is relatively more advantageous than monoethanolamine in terms of efficiency and cost, which could be further improved with enhanced heat and mass recovery.