Investigation of Alternative Strategies for Integrating Post-combustion CO₂ Capture to a Natural Gas Combined Cycle Power Plant

With increasing urgency for global action toward climate change mitigation, this study is undertaken to evaluate integration options for post-combustion CO₂ capture (PCC) on gas-fired power plants. High-fidelity models of a natural gas combined cycle power plant, a PCC plant, and a CO₂ compression train are integrated for a 90% CO₂ capture level. Three options to provide steam for solvent regeneration are explored: extracting steam from the intermediate-pressure (IP)/low-pressure (LP) crossover, using a gas-fired package boiler, and extracting steam from the LP drum. The effect of pressure losses because of steam extraction, a factor ignored in previous analyses, is also considered. The integrated plant net efficiency is 47.8, 40.4, and 44.9%, respectively, for the aforementioned scenarios. Next, supplementary firing of gas turbine exhaust is employed to generate an ample amount of steam to preserve plant net output under a sliding pressure scenario and meet solvent regeneration requirements. It is observed that the net plant efficiency converges to a value of 43.5% for the options considered.