(189l) Simulation of Post-Combustion CO2 Capture by Reactive Sorbents

The state of the art post-combustion CO2 capture processes for coal-based power plants include absorption processes based on amines and chilled ammonia. Because of the high heats of reaction, the amine-based processes need up to 30% of power plant's output for CO2 capture and compression and can lead to an 80-100% increase in the power cost. The overall energy required for the chilled ammonia process is not substantially lower than the amine process after including the energy required for feed chilling. Both physical and chemical sorbents have been proposed as alternatives to the solvent-based processes. The heats of reaction for chemical sorption, using supported carbonates and amines as sorbents, are similar to the heats of reaction for amine-based absorption though the overall energy requirement may be lower as the latent heat of vaporization for water in the amine solution does not have to be provided for the sorbent-based processes. This paper will present an analysis of CO2 capture by reactive sorbents using an adsorption process simulator (ADSIM). The overall energy and capital requirements for the processes based on chemical sorption will also be presented for a 500 MW coal-based power plant. These results will be compared with the amine-based absorption processes to help answer the question whether a chemical sorption process has a potential for lowering the cost of CO2 capture compared to amine-based absorption process. The areas for potential improvements will be pointed out.