Part Load Behaviour of Power Plants with a Retrofitted Post-combustion CO2 Capture Process

The flexible and part load operation of fossil-fuelled power plants will increase due to the higher share of fluctuating renewable energies, like wind and solar power. In this work the part load behaviour of the post-combustion CO2 capture (PCC) process is evaluated. The net efficiency of the conventional hard-coal-fired power plant decreases from 45.6% at full load to 41.5% at 40% load. The net efficiency with PCC using 7 m MEA (monoethanolamine) as solvent decreases to 34.8% at full load and to 30.1% at 40% load. The pressure of the intermediate pressure/low pressure crossover section has major influence on the efficiency. In part load higher pressures are in advantage due to lower throttling losses. The shutdown of the PCC is a possibility to generate balancing power. A reduced capture rate of 75% leads to a generation of 5% additional power.