scholarly journals Selection of Mixed Amines in the CO2 Capture Process

2021 ◽  
Vol 7 (1) ◽  
pp. 25
Author(s):  
Pao-Chi Chen ◽  
Hsun-Huang Cho ◽  
Jyun-Hong Jhuang ◽  
Cheng-Hao Ku
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Co2 Capture ◽  
Absorption Rate ◽  
Absorption Efficiency ◽  
Optimum Conditions ◽  
Capture Process ◽  
Overall Mass Transfer Coefficient ◽  
Selection Of

In order to select the best mixed amines in the CO2 capture process, the absorption of CO2 in mixed amines was explored at the required concentrations by using monoethanolamine (MEA) as a basic solvent, mixed with diisopropanolamine (DIPA), triethanolamine (TEA), 2-amino-2-methyl-1-propanol (AMP), and piperazine (PZ). Here, a bubble column was used as the scrubber, and a continuous operation was adopted. The Taguchi method was used for the experimental design. The conditional factors included the type of mixed amine (A), the ratio of the mixed amines (B), the liquid feed flow (C), the gas-flow rate (D), and the concentration of mixed amines (E). There were four levels, respectively, and a total of 16 experiments. The absorption efficiency (EF), absorption rate (RA), overall mass transfer coefficient (KGa), and scrubbing factor (ϕ) were used as indicators and were determined in a steady-state by the mass balance and two-film models. According to the Taguchi analysis, the importance of the parameters and the optimum conditions were obtained. In terms of the absorption efficiency (EF), the absorption rate (absorption factor) (RA/ϕ), and the overall mass transfer coefficient (KGa), the order of importance is D > E > A > B > C, D > E > C > B > A, and D > E > C > A > B, respectively, and the optimum conditions are A1B4C4D3E3, A1B3C4D4E2, A4B2C3D4E4, and A1B1C1D4E1. The optimum condition validation results showed that the optimal values of EF, RA, and KGa are 100%, 30.69 × 10−4 mol/s·L, 1.540 l/s, and 0.269, respectively. With regard to the selection of mixed amine, it was found that the mixed amine (MEA + AMP) performed the best in the CO2 capture process.

scholarly journals Mass Transfer Correlation and Optimization of Carbon Dioxide Capture in a Microchannel Contactor: A Case of CO2-Rich Gas

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5465
Author(s):  
Nattee Akkarawatkhoosith ◽  
Wannarak Nopcharoenkul ◽  
Amaraporn Kaewchada ◽  
Attasak Jaree
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Co2 Capture ◽  
Volumetric Flow Rate ◽  
Absorption Efficiency ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Volumetric Mass Transfer Coefficient

This work focused on the application of a microchannel contactor for CO2 capture using water as absorbent, especially for the application of CO2-rich gas. The influence of operating conditions (temperature, volumetric flow rate of gas and liquid, and CO2 concentration) on the absorption efficiency and the overall liquid-side volumetric mass transfer coefficient was presented in terms of the main effects and interactions based on the factorial design of experiments. It was found that 70.9% of CO2 capture was achieved under the operating conditions as follows; temperature of 50 °C, CO2 inlet fraction of 53.7%, total gas volumetric flow rate of 150 mL min−1, and adsorbent volumetric flow rate of 1 mL min−1. Outstanding performance of CO2 capture was demonstrated with the overall liquid-side volumetric mass transfer coefficient of 0.26 s−1. Further enhancing the system by using 2.2 M of monoethanolamine in water (1:1 molar ratio of MEA-to-CO2) boosted the absorption efficiency up to 88%.

Modeling Vapor Transport in a Hollow Fiber Membrane Humidifier Using ε-NTU Approach

2020 ◽  
Author(s):  
Hoang Nghia Vu ◽  
Xuan Linh Nguyen ◽  
Sangseok Yu
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Fuel Cell ◽  
Relative Humidity ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Water Content ◽  
Vapor Transport ◽  
Overall Mass Transfer Coefficient ◽  
Mass Exchanger

Abstract In a fuel cell vehicle, the water content of the gas supply within certain ranges plays a key role in improving the performance of a proton exchange membrane. The lower limit of water content in the air supply is to avoid the problem of drying-out, while the upper prevents flooding. Water management can be accomplished by a membrane humidifier which allows water vapor to permeate the mixture from the side having the higher water concentration, moving to the other side of the membrane. In this study, the variation in water content collected at the outlet of a membrane humidifier is investigated with a one-dimensional mass exchanger model and various operating variables. The vapor concentration of outlet flows is affected by operating temperature and relative humidity of the membrane humidifier. Relative humidity of the dry side at the point of outlet flow, to be supplied to the fuel cell module, is the key characteristic. The analogy of the effectiveness-NTU approach for heat transfer is used to analyze the characteristics of the mass exchanger. Mass flux through the membranes is estimated with an overall mass transfer coefficient which represents vapor transport characteristics moving through the membrane module. This coefficient has a similar role to the overall heat transfer coefficient in heat exchanger analysis. This parametric study is conducted to understand the effects of different variables. The Effectiveness-NTU methodology of mass transfer uses the overall mass transfer coefficient and the mass transfer rate, as evaluated experimentally. Simulink software is then employed to deliver outcomes of the model for different operating conditions.

scholarly journals Overall Mass Transfer Coefficient of CO2 Absorption in a Diameter-varying Spray Tower

2017 ◽  
Vol 114 ◽  
pp. 1665-1670 ◽  
Author(s):  
Xiaomei Wu ◽  
Min He ◽  
Yunsong Yu ◽  
Zhen Qin ◽  
Zaoxiao Zhang
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Co2 Absorption ◽  
Spray Tower ◽  
Overall Mass Transfer Coefficient

scholarly journals Dynamics simulation of ammonia nitrogen absorption in a rural–urban canal on the Northeast China Plain

2018 ◽  
Vol 78 (3) ◽  
pp. 622-633 ◽  
Author(s):  
Yujia Song ◽  
Xiaodong Wang ◽  
Haiying Zhang
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Absorption Rate ◽  
Ammonia Nitrogen ◽  
Dynamics Simulation ◽  
Background Concentration ◽  
Absorption Length ◽  
Average Value ◽  
Variation Range

Abstract To study dynamic laws of ammonia nitrogen retention in a typical rural–urban fringe canal, NaBr was selected as a conservative tracer agent, and NH4Cl as an additive nutritive salt to conduct an instantaneously added tracer experiment outdoors. On this basis, tracer additions for spiralling curve characterisation (TASCC) method and nutritive spiral indexes were used for the quantitative depiction of retention dynamics of NH4+-N. The Michaelis–Menten (M-M) model was used to simulate absorption dynamic characteristics of NH4+-N. Results showed that the variation range of absorption length of NH4+-N under background concentration was 93.94–295.54 m with an average value of 177.41 m, the variation range of mass transfer coefficient was 0.16–0.38 mm/s with an average value of 0.26 mm/s, and the variation range of absorption rate was 0.16–0.38 mg/(m2⋅s) with an average value of 0.26 mg/(m2⋅s). The maximum absorption rate of NH4+-N obtained via M-M equation simulation was 0.59–1.38 mg/(m2⋅s), and the subsaturation constant was 1.10–5.03 mg/L. The variability of the dynamic absorption length, overall dynamic absorption rate, and overall dynamic mass transfer coefficient shown by NH4+-N within the range from background concentration to saturation concentration certified that TASCC could analyse the dynamic process of NH4+-N retention and absorption by the canal.

A Mathematical Model of Evaporation and Dissolution From Oil Spills on Ice, Land, Water and Under Ice

1975 ◽  
Vol 10 (1) ◽  
pp. 132-141 ◽  
Author(s):  
P.J. Leinonen ◽  
D. Mackay
Keyword(s):  
Mass Transfer ◽  
Crude Oil ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Oil Spills ◽  
Aquatic Toxicity ◽  
Eddy Diffusivity ◽  
Model Parameters ◽  
Evaporation Flux ◽  
Selection Of

Abstract Mathematical models are presented which quantify the processes of evaporation and dissolution of components of crude oil in three situations: a spill on water, a spill on ice, and a spill under ice cover in which the oil lies between the water and ice phases. Constant spill area is assumed. The evaporation flux is calculated using a mass transfer coefficient based on windspeed and spill dimensions. The dissolution flux can be calculated from two models, a mass transfer coefficient approach and an eddy diffusivity approach involving the integration of a set of partial differential equations in depth and time. The selection of model parameters is discussed. For the three physical situations, using a synthetic crude oil, results are presented giving the relative rates of evaporation and dissolution and the aqueous phase concentration of selected hydrocarbons. The implications of the results for clean-up technology and aquatic toxicity are discussed, particularly with regard to spills under ice.

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