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.

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.

Capture of Carbon Dioxide Using Aqueous Ammonia in a Lab-Scale Stirred-Tank Scrubber

2014 ◽  
Vol 955-959 ◽  
pp. 1927-1934 ◽  
Author(s):  
Pao Chi Chen ◽  
L.C. Lin
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Absorption Rate ◽  
Aqueous Ammonia ◽  
Ph Value ◽  
Stirred Tank ◽  
Process Variables

A pH-stat stirred-tank scrubber for capturing carbon dioxide using aqueous ammonia was used to explore the effects of process variables on the absorption of carbon dioxide. In order to maintain the pH value of the solution, aqueous ammonia was automatically introduced into the tank through the action of a pH-controller. The process variables were the pH of the solution, gas-flow rate, gas concentration and stirring speed. The absorption rate and mass-transfer coefficient could be determined by means of mass balance at a steady-state. It was found that the liquid-flow rate was 0.50-58.33 ml/min; the removal efficiency was in the range of 30.1-100% and the loading of CO2 was in the range of 0.02425-0.5661 mol-CO2/mol-NH3. The results also showed that the absorption rate was in the range of 5.14x10-5 to 6.27x10-4 mol/s-L, while the mass-transfer coefficient was in the range of 0.015 to 0.14 1/s. The effects of mixing on the absorption rate, mass-transfer coefficient and loading of CO2 were also discussed in this work.

scholarly journals The Effect of Various Nanofluids on Absorption Intensification of CO2/SO2 in a Single-Bubble Column

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 393 ◽  
Author(s):  
Karamian ◽  
Mowla ◽  
Esmaeilzadeh
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Absorption Rate ◽  
Bubble Column ◽  
Pure Water ◽  
Experimental Studies ◽  
Bubble Liquid ◽  
Acidic Gases ◽  
The Impact

Application of nanoparticles in aqueous base-fluids for intensification of absorption rate is an efficient method for absorption progress within the system incorporating bubble-liquid process. In this research, SO2 and CO2 were separately injected as single raising bubbles containing nanofluids to study the impact of nanoparticle effects on acidic gases absorption. In order to do this, comprehensive experimental studies were done. These works also tried to investigate the effect of different nanofluids such as water/Al2O3 or water/Fe2O3 or water/SiO2 on the absorption rate. The results showed that the absorption of CO2 and SO2 in nanofluids significantly increases up to 77 percent in comparison with base fluid. It was also observed that the type of gas molecules and nanoparticles determine the mechanism of mass transfer enhancement by nanofluids. Additionally, our findings indicated that the values of mass transfer coefficient of SO2 in water/Al2O3, water/Fe2O3 and water/SiO2 nanofluids are, respectively, 50%, 42% and 71% more than those of SO2 in pure water (kLSO2-water=1.45×10-4 m/s). Moreover, the values for CO2 in above nanofluids were, respectively, 117%, 103% and 88% more than those of CO2 in water alone (kLCO2-water=1.03×10-4 m/s). Finally, this study tries to offer a new comprehensive correlation for mass transfer coefficient and absorption rate prediction.

scholarly journals The effects of ejector adiabatic absorber on heat and mass transfer of binary nanofluid with heat transfer additives

2021 ◽  
Author(s):  
Umar Aliyu Muhammad ◽  
Debabratta Bhattacharyya ◽  
Jose Louis Endrino ◽  
Sonia Fereres
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Heat And Mass Transfer ◽  
Transfer Rate ◽  
Absorption Rate ◽  
Alumina Nanoparticles ◽  
Alumina Nanofluid

AbstractThis paper presents experimental results on the study of the effects of ejector adiabatic absorber on heat and mass transfer of binary nanofluid with heat transfer additives (2-ethyl-1-hexanol and gum Arabic). In this case, H2O/lithium bromide-alumina nanofluid was suggested due to a growing interest in absorption heat transfer working fluid for solar energy application. An experimental setup — ejector test rig — was designed to study the absorption, heat, and mass transfer rate as a result of refrigerant vapour mass flow entrained by the ejector adiabatic absorber. The study was carried out at different solution mass flowrate (0.051 to 0.17 kg/s) with three prepared sample solutions, which include pure LiBr solution, LiBr-Alumina nanofluid without heat transfer additives, and LiBr-Alumina nanofluid with heat transfer additives. The absorption rate, mass transfer coefficient, heat transfer rate, and heat transfer coefficient for the three samples were reported. On the other hand, the percentage enhancements for all the parameters — at a suitable flow rate of 0.085 kg/s — due to the addition of alumina without and with heat transfer additives were recorded. The absorption rate enhancements were 25% and 96%, the enhancement rates of mass transfer coefficient recorded were 20% and 82%, the heat transfer rate enhancements were 85% and 183%, and the heat transfer coefficient enhancements obtained were 72% and 156% with addition of alumina nanoparticles only and alumina nanoparticles with heat transfer additives respectively. Material mass balance analysis suggests that mass inflow in the ejector equals to the mass outflow from the ejector, indicating a complete absorption of the entrained refrigerant vapour beyond which falling film absorption can occur due to concentration. This article also presents experimental evidence of the capability of ejector as strong adiabatic absorber, heat, and mass transfer component, which were earlier reported using numerical models.

Absorption of oxygen into solutions of polymers

1986 ◽  
Vol 51 (10) ◽  
pp. 2127-2134 ◽  
Author(s):  
František Potůček ◽  
Jiří Stejskal
Keyword(s):  
Mass Transfer ◽  
Aqueous Solutions ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Liquid Flow ◽  
Flow Curve ◽  
Liquid Flow Rate ◽  
Polymer Concentration ◽  
Newtonian Liquids

Absorption of oxygen into water and aqueous solutions of poly(acrylamides) was studied in an absorber with a wetted sphere. The effects of changes in the liquid flow rate and the polymer concentration on the liquid side mass transfer coefficient were examined. The results are expressed by correlations between dimensionless criteria modified for non-Newtonian liquids whose flow curve can be described by the Ostwald-de Waele model.

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