Innovative Absorber/Stripper Configurations for CO₂ Capture by Aqueous Monoethanolamine

Abstract

The state-of-the-art technology to capture CO2 from coal-fired power plants is absorption/stripping with aqueous monoethanolamine (MEA). The energy consumption in stripping can be 15−30% of the power-plant output. A rigorous rate-based model for CO2−MEA−H2O was used to simulate several flowsheet alternatives that reduce the energy requirement using Aspen Plus with RateFrac. Results were calculated for vapor recompression, multipressure, and simple strippers at 5 and 10 °C approach temperatures and 70, 90, and 95% CO2 removal. The “equivalent work of steam/mole of CO2 removed” and the reboiler duty were used to compare the proposed schemes and to show the shift of energy use from work to heat. The total equivalent work for multipressure was less than that for the simple stripper by 0.03−0.12 GJ/(ton of CO2), and the reboiler duty was less by 0.15−0.41 GJ/(ton of CO2). The multipressure with vapor recompression is an attractive option because it utilizes the overhead water vapor latent heat to reduce reboiler duty load, recovers the work of compression to strip more CO2, and shows more reversible behavior.

An FTIR Spectroscopic Study on the Effect of Molecular Structural Variations on the CO2 Absorption Characteristics of Heterocyclic Amines

“…[1] The major challenge leading up to the deployment of aqueous, amine-based PCC on a large scale is adapting the existing technology to suit typical flue-gas conditions from a coal-fired power plant (low CO 2 partial pressures, typically AE 1 bar, and a high volume of gas to be treated). The economics and feasibility of the process is largely dependent on the absorbent system, in particular, the capacity to absorb CO 2 , how fast it can absorb CO 2 (rate) and the energy required (heat supplied) to re-release the CO 2 and regenerate the absorbent. [2] Lower capital and operational costs are associated with higher absorption capacities and absorption rates (i.e., smaller absorption columns are required) and smaller energy requirements.…”

A Microvascular System for Chemical Reactions Using Surface Waste Heat

“…The lean MEA solution was then re-saturated with CO 2 to quantify the amount of CO 2 released. This was calculated to be 0.10 mol CO 2 /mol MEA (0.14 mol CO 2 /mol MEA is released in conventional systems), [33] corresponding to a release rate of 1.9 mg CO 2 /min. Other stripping systems, such as packed columns and membrane contactors, achieve higher fluxes of CO 2 .…”

Carbon dioxide capture using solid sorbents in a fluidized bed with reduced pressure regeneration in a downer

“…[5][6][7] The minimum energy for separation of CO 2 from flue gases, 7.3 kJ/g mol-CO 2 , is already about one-third of the energy required for separation using aqueous amines. [7][8][9] There is little room for improvement using conventional solvent technology. The size of the amine scrubber unit is fairly large.…”