Abstract
In order to be able to compare and possibly rank different technologies for CO2 capture, and different means of integrating novel process units into power cycles with CO2 capture, it is vital to apply a consistent benchmarking methodology. A benchmarking will then provide a snapshot of the performance of different novel processes, related to a well-defined reference process. Many earlier efforts on benchmarking of cycles with CO2 capture have compared different capture processes based on process simulations that determine efficiency and CO2 emissions. Recently, the sensitivity of the efficiency with respect to technological developments has been studied, but without relating the results to the maximum possible efficiency. The maximum possible efficiency has been dealt with to some extent in literature for post-combustion capture, where work requirements for amine-based CO2 capture using existing and projected technologies were compared to the theoretical minimum work requirement. The present work presents the elaboration of a consistent benchmarking methodology for evaluation of different CO2 capture processes. The first step in the methodology is carried out prior to process simulations and consists in determining the thermodynamic maximum efficiency. This is done by establishing minimum work targets for the process under consideration without defining the specifics of the unit operations involved. To ensure no bias when evaluating the targets only the inputs and outputs of a process are specified. Particular attention is given to the CO2 capture ratio specification. The three major process routes for CO2 capture (post-, oxy-fuel and pre-combustion) are evaluated and the results analyzed. Though the thermodynamic maximum efficiency will never be achieved in practise, it provides a common and definite basis for comparison of different processes. Subsequently including technology limitations and performing the process simulations, enables the identification o