Pressurized oxy-combustion has been identified by DOE as a transformational technology for coal power with carbon capture due to the advantages that are realized when the combustion process is pressurized. The staged pressurized oxy-combustion (SPOC) process is particularly attractive as the efficiency of the process is almost 6 percentage points greater than that of first generation oxy-combustion. A critical component of the SPOC process, and potentially other pressurized combustion processes, is the Direct Contact Cooler (DCC) where the latent heat of the flue gas moisture is recovery to improve plant efficiency while simultaneously removing SOx and NOx from the flue gas, so that the FGD and de-NOx processes can be eliminated, and the cost of electricity minimized. The objective of this R&D effort was to advance the TRL of the DCC technology, which included performance testing at a 100 kW scale to validate the process and obtain key engineering data for scale-up. A collateral objective was to study the gas- and liquid-phase kinetics, and the development of a systematic chemical mechanism validated by experimental data. Experiments in a bench-scale stirred reactor provided an updated understanding of the liquid chemistry and the effects of temperature and pH. This information was used to develop a reduced reaction mechanism, which was subsequently incorporated in an ASPENbased process model, to allow for evaluation of the DCC at full scale. A small-pilot DCC column was designed, constructed and tested using simulated flue gas at the pressurized oxy-combustion test facility at Washington University in St. Louis. In the majority of tests, the SO2 capture approached 100%, making the NOx capture the primary metric of capture efficiency. An NOx capture efficiency of 90% was achieved when the gas residence time was 95 seconds, demonstrating that high capture rates can be attained with reasonable reactor size. At higher temperatures (up to 200�C inlet gas temperature) the total NOx scrubbing efficiency was reduced by approximately 10% (compared to room temp.) and this was attributed to a reduced NO oxidation rate. A significant amount of SO2 was present in the gas outlet (10%) only when the temperature was high and the N:S ratio was low (N/S <
1), which highlights the necessity of controlling the NOx concentration in the flue gas for complete sulfur scrubbing. After incorporated our optimized chemical mechanism into an ASPEN process model, various full-scale configurations of the DCC were evaluate, and the results indicate that the proposed DCC can accomplish its intended goals at full scale and at a modest size. Thus, the results of this project indicate that the DCC is a promising technology for recovery of the latent heat of the moisture in the flue gas while simultaneously scrubbing the nitrogen and sulfur oxides, thus enabling pressurized oxy-combustion, in general, and the SPOC process, in particular.