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Modeling and Simulation of Gas Absorption in Hollow Fiber Membrane Contactors Using Nanofluids

Karimi, Rezvan | 2019

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 51744 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Molaei Dehkordi, Asghar
  7. Abstract:
  8. Today, the usage of hollow membrane contactors is considered by the researchers as a novel solution in the separation and purification industry, including the sweetening of gas. Improving the performance of these devices requires a more detailed study of the process factors and changes in its chemistry. Hence, providing a suitable mathematical model by examining the details of the flow pattern within the contactor is based on the computational fluid dynamics technique in the agenda. Also, improving the absorption of components such as carbon dioxide and hydrogen sulfide from the gas mixture using chemical absorbents such as monoethanolamine will be investigated. The change in the mass transfer coefficients and the physical properties of the fluid in the presence of effective nanoparticles, such as silica, carbon nanotubes, are modeled by considering the existing of theories for Brownian motion and Grazing effect. In the end, the numerical solution of the governing equations and the simulation of the system affect the effective parameters and operational variables. In this Simulation, a complete mathematical model taking into account the entrance regions of hydrodynamics, thermal energy, and mass transport was developed. Comsol software were used to solve the governing equations numerically and the model predictions were satisfactorily validated against experimental data reported in the literature concerning the absorption of carbon dioxide by means of various nanofluids such as silica/water and CNT/water and conventional reactive absorption by means of MEA and good agreement was found. In addition, effects of various operating parameters such as the concentration of nanofluids, solvent and gas-phase flow rates, carbon dioxide inlet concentration, and the solvent and gas-phase inlet temperatures on the contactor performance were carefully examined. It was found that at identical mass fraction of SiO2 and CNT nanoparticles (i.e., 0.001) in MEA solution (reactive absorption) the enhancement factor is 2.37% and 8.45%, respectively, whereas the corresponding values are 4.44% and 18.51% for the physical absorption of CO2 in water-based nanofluids
  9. Keywords:
  10. Gas Absorption ; Membrane Contactor ; Nanofluid ; Gas Sweetening ; Computational Fluid Dynamics (CFD) ; Adsorption Simulation

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