Technoeconomic Assessment of an Advanced Aqueous Ammonia-Based Postcombustion Capture Process Integrated with a 650-MW Coal-Fired Power Station.

Using a rigorous, rate-based model and a validated economic model, we investigated the technoeconomic performance of an aqueous NH-based CO capture process integrated with a 650-MW coal-fired power station. First, the baseline NH process was explored with the process design of simultaneous capture of CO and SO to replace the conventional FGD unit. This reduced capital investment of the power station by US$425/kW (a 13.1% reduction). Integration of this NH baseline process with the power station takes the CO-avoided cost advantage over the MEA process (US$67.3/tonne vs US$86.4/tonne). We then investigated process modifications of a two-stage absorption, rich-split configuration and interheating stripping to further advance the NH process. The modified process reduced energy consumption by 31.7 MW/h (20.2% reduction) and capital costs by US$55.4 million (6.7% reduction). As a result, the CO-avoided cost fell to $53.2/tonne: a savings of $14.1 and $21.9/tonne CO compared with the NH baseline and advanced MEA process, respectively. The analysis of energy breakdown and cost distribution indicates that the technoeconomic performance of the NH process still has great potential to be improved.