This research program is focused on CO₂ capture from flue gas by alkanolamine absorption/ stripping.  Our objective is to develop an evolutionary improvement to monoethanolamine (MEA) absorption/stripping for CO₂ capture from coal-fired flue gas.

There are currently eight graduate students working on CO₂ rate measurements, amine degradation, systems modeling, and pilot plant testing. The solvents piperazine/K₂CO₃, MEA/PZ, and DGA are being studied with these methods.

We are using a wetted wall column to obtain CO₂ kinetics and solubility at absorber and stripper conditions with DGA and potassium carbonate promoted by piperazine and morpholine.  Future work will include measurements of PZ/K₂CO₃ at stripper conditions and measurements with loaded MEA containing piperazine and sulfate.  We are also determining speciation of these solutions with NMR at 25 to 60°C.

We are measuring rates of oxidative degradation of MEA by the evolution of ammonia from a stirred cell reactor.  Both dissolved iron and dissolved copper are catalysts for this process.  We will add the capability to determine oxygen uptake/mass transfer and the concentrations of degradation products.  We have initiated studies of piperazine degradation.  After completing comprehensive studies of MEA degradation, we will look at oxidative degradation of piperazine, MDEA, and other potentially useful amines.

A rigorous modeling activity is providing the basis for interpolating and extrapolating bench and pilot-scale experimental results.  We have developed and are continuously improving rigorous submodels of reactive mass transfer and thermodynamics for MEA, DGA, and promoted potassium carbonate.  We have completed the process of integrating these submodels with RateFrac™ in AspenPlus to predict absorption/stripping performance in MEA systems and are developing a similar model for promoted potassium carbonate.  This integrated model will permit optimization of the specific solvent systems and virtual testing of process improvements such as alternative packing, split feed to the absorber, and reduced pressure in the stripper.  The integrated model will be validated with data from our pilot testing.

A carefully controlled pilot plant study will provide quantitative screening of contactor alternatives and will demonstrate important process concepts.  Equipment modifications have been completed in the existing facility at the Pickle Research Center to permit testing with air/CO₂ in a 16.8-inch absorber/stripper.  The stripper will be tested at 0.2 to 4 atm.  Promoted potassium carbonate will be tested with one structured packing and one dumped packing.  The pilot plant work also includes testing of CO₂ absorption in 0.1 M NaOH in a 16.8-inch air-water column to screen alternative types of dumped and structured packing.

Luminant Carbon Management Program

Click here to see the prospectus for the program.