A novel post-combustion CO2 capture process for natural gas combined cycle power plant based on waste energy utilization and absorption heat transformer

In this paper, a novel post-combustion carbon capture (PCC) process is proposed for reducing the efficiency penalty of a decarbonized natural gas combined cycle (NGCC) power plant based on waste energy utilization and absorption heat transformer (AHT). The process incorporates a letdown steam turbine recovering the throttling loss of extracted steam integrated with lean vapor compression along with intensified CO2 compression utilizing liquefied natural gas cold energy. In addition, the cooling heat of flue gas, stripper top stream, reboiler condensate, and compressed CO2 are recovered to heat driving heat source which drives AHT, and the superheat of extracted steam is further utilized. The results show that the regeneration energy consumption is decreased by 18.03 % compared with conventional PCC, and the amount of extracted steam decreases from 68.21 kg/s to 46.55 kg/s, net power output efficiency increases from 48.88 % to 51.40 %, decreasing the efficiency penalty from 13.72 % to 9.27 %. Furthermore, the energy consumption of carbon capture is reduced by 137.3 kWh/t, and the levelized fuel consumption and levelized carbon emission are decreased by 7.6 g/kWh and 2.05 g/kWh, respectively. Exergy analysis indicates that the exergy destruction is reduced by 24.23 MW and the exergy efficiency is increased by 3.29 %.