Process Modeling of CO₂ Absorption with Monoethanolamine Aqueous Solutions Using Rotating Packed Beds

Abstract

A first-principle process simulation model is presented for the chemical absorption of carbon dioxide (CO 2 ) with monoethanolamine (MEA) aqueous solutions using rotating packed beds (RPB). Built on a proven rate-based packed bed absorber model, the RPB model rigorously simulates the phase and chemical equilibria at the vapor−liquid interface, the heat and mass transfer across the gas and liquid films, the fast reactions between MEA and CO 2 in the liquid film, and the RPB hydraulics. Estimation of the rate of transfer of mass across the liquid film is central to accurate simulation of the CO 2 absorption process with MEA aqueous solutions. We show that the literature lab-scale RPB data for CO 2 removal efficiency can be satisfactorily correlated by introducing a correction factor for the effective packing surface area predicted by the Onda correlation. Given the validated RPB model, we further show that, among the gas-phase mass transfer coefficient, the liquid-phase mass transfer coefficient, and the reaction rate constant for the reaction between amine and CO 2 , the reaction rate constant is the controlling step with the greatest potential to enhance the CO 2 absorption performance in RPB.

New Formula for Direct Prediction of the Effective Thermal Conductivity of the Ellipsoidal Granular Bed at High Temperatures

“…Therefore, k λ + k c in our simulation is larger than that of the ZBS model, and the corresponding relative error is about 30%, as shown in Figure 14a. For the high-temperature bed, radiation heat transfer between particles is introduced in the BB model, and the heat flux is proportional to 4σd p T bed 3 . The calculated k r in our model is consistent with that predicted by the BB model, and the relative error is within 13% (Figure 14b).…”

“…Packed beds are frequently encountered in the mineral, chemical, , and environmental industries, and the thermal properties, especially the effective thermal conductivity (ETC), of packed beds are of great significance for their optimal design and operation. , Considering the mineral industry as an example, 160 million tons of steel slag (corresponding to the output of 1.065 billion tons of crude steel, 56.7% of global output) were generated in China’s iron and steel industry in 2020, which had a heat equivalent of 41,000 tons of standard coal . The temperature of the discharged steel slag is over 1000 °C, and the waste heat is of a high quality.…”

Electrolyte Thermodynamic Models in Aspen Process Simulators and Their Applications

“…The eNRTL model in Aspen Properties has been used to model many industrial electrolyte systems and processes to support calculations of thermodynamic properties, calorimetric properties, fluid phase equilibria including salt solubilities, and heat and mass balances. Some prominent industrial applications includes acid gas removal, sour water stripping, sulfuric acid production, caustic brine evaporation, nitric acid dehydration, − trona processing, hybrid sulfur cycle process for hydrogen production, high salinity brines treatment and desalination, , CO 2 capture with aqueous amine solutions − and with aqueous potassium carbonates, and, most recently, CO 2 solubility in brine solutions for sequestration in deep saline aquifers, , etc. As an illustration, Figure shows the experimental data and the eNRTL model results for CO 2 solubility in pure water, 10 wt % single salt solutions, and 10 wt % mixed salt solutions of NaCl + KCl (1:1 weight ratio), NaCl + CaCl 2 (1:1 weight ratio), KCl + CaCl 2 (1:1 weight ratio), and NaCl + KCl + CaCl 2 (1:1:1 weight ratio) at 318.15 K. The applications on CO 2 capture with aqueous amine solutions and high salinity brine treatments are briefly summarized below.…”

“…Figure shows the experimental data and the model results for CO 2 partial pressure as a function of CO 2 to MEA molar ratio at 313, 353, and 393 K . Of particular interest is the calculation of true species compositions and activities used in the reaction kinetics rate expressions within the rate-based absorption/desorption simulation models for accurate simulation of amine units . The technical details for the modeling and simulation of amine units have been elaborated in our previous works. ,− …”

Modeling of Nitrogen Removal from Natural Gas in Rotating Packed Bed Using Artificial Neural Networks

“…Over the last few years, numerous experiments [ 31 , 32 , 33 , 34 ], simulations and modelling [ 35 , 36 , 37 , 38 ], and computational fluid dynamics (CFD)-based hydrodynamic studies [ 39 , 40 , 41 , 42 ] were conducted to procure a better understanding of the mass transfer within the RPB in high gravity environments and to improve the technology. Nonetheless, a majority of the reports were based on the absorption process and were operated under five bars and above zero temperatures.…”