Entropy Generation Analysis of a Chemical Absorption Process Where Carbon Dioxide is Absorbed by Falling Monoethanolamine Solution Film

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Imen Chermiti ◽  
Nejib Hidouri ◽  
Ammar Ben Brahim
Keyword(s):  
Mass Transfer ◽  
Chemical Reaction ◽  
Entropy Generation ◽  
Co2 Absorption ◽  
Falling Film ◽  
Total Entropy ◽  
Absorption Process ◽  
Viscous Effects ◽  
Chemical Absorption ◽  
Falling Liquid Film

The present paper reports a study about entropy generation analysis for the case of chemical absorption of a gas into laminar falling liquid film. The CO2 absorption into monoethanolamine (MEA) aqueous solutions has been considered. Temperature and concentration expressions are determined by using Laplace transform and used for the entropy generation calculation. The effects of irreversibilities due to heat transfer, mass transfer, viscous effects, coupling effects between heat and mass transfer, and chemical reaction on the total entropy generation of the considered system are derived. The obtained results show that entropy generation is mainly due to chemical reaction irreversibility at the gas–liquid interface. Between this interface and the reaction film thickness (where the reaction take place), entropy generation is due to both chemical reaction and mass transfer irreversibilities. More details concerning the contribution of each kind of irreversibility to entropy generation through the falling film are graphically presented and discussed.

Research Trends of Carbon Dioxide Capture using Ionic Liquids and Aqueous Amine-Ionic Liquids Mixtures

2016 ◽  
Vol 13 (1) ◽  
pp. 53
Author(s):  
Siti Nabihah Jamaludin ◽  
Ruzitah Mohd Salleh
Keyword(s):  
Ionic Liquids ◽  
Co2 Capture ◽  
Membrane Separation ◽  
Carbon Dioxide Capture ◽  
Global Climate ◽  
Research Trends ◽  
Co2 Absorption ◽  
Absorption Process ◽  
Chemical Absorption ◽  
Factors Influencing

Anthropogenic CO2 emissions has led to global climate change and widely contributed to global warming since its concentration has been increasing over time. It has attracted vast attention worldwide. Currently, the different CO2 capture technologies available include absorption, solid adsorption and membrane separation. Chemical absorption technology is regarded as the most mature technology and is commercially used in the industry. However, the key challenge is to find the most efficient solvent in capturing CO2. This paper reviews several types of CO2 capture technologies and the various factors influencing the CO2 absorption process, resulting in the development of a novel solvent for CO2 capture.

Effect of Nanoparticles on H2O/LiBr Falling Film Absorption Process

2016 ◽  
Author(s):  
L. Y. Zhang ◽  
Y. Li ◽  
Y. Wang ◽  
L. X. Cao ◽  
X. Z. Meng
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Fe3o4 Nanoparticles ◽  
Falling Film ◽  
Absorption Process ◽  
Nanoparticle Concentration ◽  
Water Vapor Absorption ◽  
Libr Solution ◽  
Falling Film Absorption ◽  
Film Absorption

Absorber is an important component in absorption refrigerating system. Its performance plays a significant role on the overall efficiency of absorption refrigerating system. The nanofluids which can enhance the heat and mass transfer will be utilized to absorber for enhancing the water vapor absorption process and improving the absorber efficiency. The software CFD-FLUENT is used to analyze the falling film absorption process of the nanofluids, which consists of H2O/LiBr solution with Fe3O4 nanoparticles in this paper. The results indicate that the enhancing heat and mass transfer of nanofluids is related to the nanoparticle concentration and size. The stronger the nanoparticle concentration, the greater enhancement of heat and mass transfer of falling film; while the smaller the nanoparticle size, the greater enhancement of heat and mass transfer of falling film. It is also found that the enhancement ratio of heat and mass transfer flux reach 1.48 and 1.37, respectively, as the Fe3O4 nanoparticles mass concentration of 0.01wt% and the size of 50nm.

scholarly journals Modeling of conjugated heat and mass transfer in the entrance region of falling liquid film at various values of the Froude number

2018 ◽  
Vol 194 ◽  
pp. 01007
Author(s):  
Maria V. Bartashevich
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Liquid Film ◽  
Froude Number ◽  
Heat And Mass Transfer ◽  
Water Solution ◽  
Lithium Bromide ◽  
Entrance Region ◽  
Falling Film ◽  
Falling Liquid Film

Mathematical model of conjugated heat and mass transfer in absorption on the entrance region of the semi-infinite liquid film of lithium bromide water solution is investigated for different values of Froude number. The calculations shown that larger values of Froude number corresponds to a smaller thickness of the falling film. It was demonstrated that for large values of the Froude number the heat transfer from the surface is greater than for smaller values.

Second Law Based Optimization of Falling Film Single Tube Absorption Generator

2002 ◽  
Author(s):  
Saeid Jani ◽  
Mohamad H. Saidi ◽  
Ali Heydari ◽  
Ali A. Mozaffari
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Entropy Generation ◽  
Horizontal Tube ◽  
Heat Transfer Fluid ◽  
Falling Film ◽  
Efficient Design ◽  
Single Tube ◽  
Evaporation Heat ◽  
Dimensionless Correlations

The objective of this paper is to provide optimization of falling film Li/Br solution on a horizontal single tube based on minimization of entropy generation. Flow regime is considered to be laminar, the effect of boiling has been ignored and wall temperature is constant. Velocity, temperature and concentration distributions are numerically determined and dimensionless correlations are obtained for predicting the average heat transfer coefficient and average evaporation factor on the horizontal tube. Thermodynamic imperfection due to passing lithium bromide solution is attributed to non-isothermal heat transfer; fluid flow friction and mass transfer irreversibility. Scale analysis shows that the momentum and mass transfer irreversibilities can be ignored at the expense of heat transfer irreversibility. In the process of optimization, for a specified evaporation heat flux, the entropy generation along with the developed heat and mass transfer dimensionless correlations is minimized and the optimal geometry and the optimum thermal hydraulic parameters are revealed. The investigation cited here indicates the promise of entropy generation minimization as an efficient design and optimized tool.

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