Evaluation and comparison of the part load behaviour of the CO₂ capture technologies oxyfuel and post-combustion

Abstract

The rising share of fluctuating renewable energies increasingly demand flexible and part load operation of fossil-fuelled power plants with and without CCS. In this work the part load behaviour of the Oxyfuel and the post-combustion CO₂capture processes are evaluated and compared. The net efficiency of the conventional hard-coal-fired power plant decreases from 45.2% at full load to 41.6% at 40% load. The net efficiency with post-combustion CO₂capture using 7 m MEA as solvent decreases to 34.7% at full load and 30.2% at 40% load. The Oxyfuel process reaches in turn a net efficiency of 36.6% at full load and 32.3% at 40% load and shows therefore a benefit of 1.9%-points at full load compared to the postcombustion CO₂capture with MEA. The efficiency advantage of the Oxyfuel process compared to the post-combustion CO₂capture process remains constant at part load.