Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6588565 | Chemical Engineering Science | 2018 | 11 Pages |
Abstract
Post-combustion CO2 capture using amine scrubbing is the most promising technology to reduce CO2 emissions from coal- or gas-fired power plants. Increasing CO2 absorption rate (kgâ²) reduces the absorber capital cost, which is the cost center of the capture plant. By partially replacing water with N-methyl-2-pyrrolidone (NMP) in 7â¯m (30â¯wt%) aqueous monoethanolamine (MEA), the CO2 absorption rate (kgâ²) is significantly enhanced because of lower CO2 loading/higher free MEA at the same CO2 partial pressure (PâCO2), greater CO2 physical solubility, and greater MEA activity. At 40â¯Â°C, in the operating range of 100-5000â¯Paâ¯PâCO2, the average kgâ² of 7â¯m MEA in 3 water/1 NMP, 1 water/3 NMP, and 1 water/19 NMP is 1.1 times, 2 times, and 5 times that of 7â¯m aqueous MEA, respectively. CO2 physical solubility, solvent viscosity, and MEA activity were measured. A kinetic model was built in MATLAB® to better understand the mass transfer of CO2 into semi-aqueous MEA (MEA-NMP-water). The model suggests that the diffusion and reaction of CO2 into aqueous MEA can be approximated by pseudo-first-order (PFO) behavior and adding NMP causes deviation from PFO by the depletion of MEA at the surface. The semi-aqueous solvent provides an excellent rate of CO2 absorption, but the increased viscosity reduces normalized capacity and the volatility of the physical solvent must be addressed.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Chemical Engineering (General)
Authors
Ye Yuan, Gary T. Rochelle,