Background/Objectives

We present the chronology of a multidisciplinary and multiinstitutional 15-year effort that spans computational materials design, synthesis and scale-up, property testing, parametric testing and process modeling of a leading single-component water-lean post-combustion CO₂ capture solvent, N-(2-ethoxyethyl)-3-morpholinopropan-1-amine (EEMPA). 

Approach/Activities

We detail the in silico design of candidate solvents, identifying critical design criteria including the placement of internal hydrogen bonding to control rheological properties such as viscosity.  We then describe synthetic approaches, taking consideration into reagent cost, toxicity and availability of reagents at tonnage quantities (assuming commerical application).  Following synthesis and characterization, we then describe comprehensive solvent testing with an emphasis on measuring vapor-liquid equilibria, CO₂ sorption kinetics, viscosity and thermal conductivity using custom-laboratory instrumentation. Parametric testing of solvent was performed on a continuous flow 5-L laboratory testing unit fed with simulated coal-derived flue gas, where EEMPA was regenerated using a simple stripper regeneration column. Subsequent testing on a 50-L unit was performed using a two-stage flash regeneration. Data from these tests and measurements were fed into ASPENplus, where a thorough techno-economic study and sensitivity analysis of EEMPA was performed and compared against NETL’s REV4 Case B12B amine baseline, which is 650 MW coal-fired powerplant.  The model assessed the performance and costs of EEMPA regenerated by simple stripper (SS) or a cheaper Two-Stage Flash (TSF) configuration.

Results/Lessons Learned

Reboiler duties for the solvent were confirmed to be 2.0 GJ/tonne CO₂, and capture efficiencies as high as 96% were achieved. Capture rates were modeled between 80 to >95%, suggesting that EEMPA is capable of high rates of capture (>90%) at costs < $40/ tonne CO₂, besting the B12B baseline ($46/tonne CO₂) by 17% in efficiency at 15% lower carbon capture costs. We close with a discussion of current preparations for testing at the National Carbon Capture Center at 0.5 MW scale and future plans for larger-scale testing at 5MW.