14. Energy Minimization in CO₂ Capture in a Natural Gas Power Plant

In the liquefied natural gas (LNG) power plant, amine scrubbing and CO₂(g) liquefaction are often used for CO₂(g) capture and storage (CCS) as it is suitable for large-scale installations. A large amount of LNG hot and cold energy is required for CO₂(g) absorption, regeneration, and liquefaction. Waste LNG cold energy discharged into seawater from the LNG regasification process and waste LNG hot energy from the natural gas combined cycle (NGCC) can be recovered and reused. In this study, the model for CCS for waste hot and cold energy recovery of LNG power plants and regasification of LNG includes NGCC, CO₂(g) capture and regeneration, and CO₂(g) liquefaction. Exergy and economic analyses are discussed to evaluate the economic feasibility of process energy conversion. Finally, the net power generation and exergy efficiency of the proposed process increased by 20% and 11%, respectively. Economic feasibility net profit increased by 78%. The overall energy efficiency and economic feasibility of using waste cold and hot energy were observed to increase, which resulted in decreased fuel usage.