23 – Power plant integration methods for liquid absorbent-based post-combustion CO2 capture

Abstract When integrating a liquid absorbent-based post-combustion CO 2 capture (PCC) plant into a coal-fired steam power plant, basic integration and heat integration have to be distinguished. Whereas the basic integration leads to a significant reduction of the net output of the power plant and thus a lower net efficiency, the heat integration leads to a reduction of the losses caused by the basic integration. Around two-thirds of the losses due to basic integration occur due to the heat duty for the reboiler of the desorber. The remaining third of the losses is due to auxiliary power for CO 2 compression, for electrical consumers in the PCC plant and for additional cooling water pumps. To determine the loss due to the heat duty for the reboiler without using a complex steam power plant model, the Power Loss Factor (PLF) can be used. Its dependence on the specific heat duty of the reboiler, the original design intermediate pressure/low pressure (IP/LP) crossover pressure of the turbine, the original design condenser pressure of the turbine, and the reboiler temperature is shown in detail. The determination of the mentioned auxiliary powers is described accordingly. For heat integration, the power gain factor is defined. Its dependence on process values is shown exemplarily for the specific heat duty of the reboiler and the maximum temperature of the waste heat while the other influencing factors are kept constant. All studies are carried out for the integration of the capture plant into a new built power plant (greenfield) as well as a retrofit of an existing one. In the final section, the use of the power loss factor is demonstrated for capture plants using monoethanolamine (MEA) and piperazine based solutions.