Simulation Of The Low-Energy Carbon Dioxide Capture Process Based On Aspen

This paper aimed to optimize the amine-based CO₂ scrubbing and CO₂ adsorption method witch are most promising for industrial application at the present stage.The novel low-energy schemes were obtained through the general simulation software Aspen and the experiments of thermodynamics and kinetics.For developing the regeneration in chemical scrubbing,an efficient regeneration method utilizing pentane to strip CO₂ directly was proposed in this work.A H₂O/Pentane-CO₂/Amine quaternary thermodynamics system rarely reported was established under the framework of ENRTLRK.The effects of three typical solvents monoethanolamine?MEA?,2-amino-2-methyl-1-propanol?AMP?,and methyldiethanolamine?MDEA?were investigated,the simulations showed pentane stripping process revealed a better performance for the energy consumption,which was15²5%and 38⁶0%lower than the direct steam stripping and the traditional regeneration with reboiler,respectively.And the lean solvent after pentane stripping had the lower temperature and CO₂ loading.The profiles of the concentration,temperature and pressure fields along the stripper demonstrated a significantly intense flash phenomenon in the direct pentane stripping,which is caused by the strong driving force of the thermally expanded gas.Substantial water evaporated by pentane stripping can break the vapor-liquid boundary layer and promoted the diffusion of CO₂ from liquid to gas for enhanced kinetics.Some categories of amines,like MDEA with the lower desorption heat and the higher CO₂ equilibrium partial pressure at the top of the stripper,could achieve better regeneration performance in the new regeneration process.Sensitivity analysis was conducted to find the factors playing an important role in the system.The results showed the temperature and the loading of rich solvents could bring great effects on the regeneration.And the condensation temperature and the compression pressure could affect the recovery of pentane observably.For enhancing the absorbing in chemical scrubbing,a liquid-liquid phase change absorption process was designed and simulated,which made up the missing of physical properties of the new absorbent.This paper summarized the parameters required for embedding DEEA based on gas-liquid equilibrium calculations in Aspen Plus and selected the experimental data under the reasonable temperatures and pressures to fit the parameters.The accuracy of the thermodynamic model had been verified through the property experiments.On the basis of DEEA/MEA physical package,an innovative DMH phase-change process was built for 150,000-ton CO₂ capturing.The simulations revealed the new process had the lowest energy and water consumption at the lean solvent loading of 0.30 and 0.25 mol CO₂/mol MEA,which is 2.69 GJ/t CO₂ and 80.6t H₂O/t CO₂ respectively,31%and 11%lower than that of the optimized conventional process with 30wt%MEA.For improving the CO₂ adsorption process,a two-bed temperature swing adsorption process with steam purging for regeneration was established.The model combination suitable for describing activated carbon adsorption was studied.The comparison between simulative and experimental breakthrough curves showed simulation without dead volume could lead to deformation,and the ideal adsorption solution-lumped resistance model had the higher consistence with experimental data.The process used the steam and the adsorbed flue gas to regenerate CO₂ and cool the bed respectively.The results showed increasing purging steam temperature could raise the CO₂ capture rate greatly and influence the energy consumption slightly,but have few effects on the CO₂ product purity.The increase of adsorption/desorption time interval could enhance the product purity significantly,but have a negative impact on capture rate and promote the energy consumption obviously.The simulation optimization of the CO₂ capture process was systematically discussed for reducing the energy consumption.The work could provide suggestions for new process design,physical package development and process engineering realization.