Numerical simulation of mass transfer in a liquid–liquid membrane contactor for laminar flow conditions

Computational simulation of CO2removal from gas mixtures by chemical absorbents in porous membranes

In this study chemical absorption of CO₂from a N₂/CO₂gas mixture in tetramethylammonium glycinate ([N₁₁₁₁][Gly]) solution using hollow-fiber membrane contactors by employing the CFD (computational fluid dynamics) method was investigated.

HIGH DISPERSION BARIUM SULFATE NANOPARTICLES PREPARED WITH DODECYL BENZENE SULFONIC ACID

Production of nanoparticles by precipitation is a relatively simple process but the control of product particle size distribution is difficult. In this paper, nanosize barium sulfate ( BaSO 4) particles are prepared with dodecyl benzene sulfonic acid (DBSA) in ethanol–water reaction system at room temperature. The BaSO4 nanoparticles are characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), powder X-ray diffraction (XRD), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR) and thermo gravimetric analysis (TGA), respectively. The results indicated that the average diameter of spherical BaSO4 is about 46 nm modified with 5 wt.% DBSA, which have good dispersion in the presence of a certain concentration NH3 ⋅ H2O . It suggests that the high dispersion is attributed to presence of a thin layer of barium alkyl sulfate, which is formed and coated onto the surface of BaSO4 particles during the reaction process. The thin films on the surface of the BaSO4 effectively modified the surface and properties, which also control the particle size and morphology.

Simulation studies of ammonia removal from water in a membrane contactor under liquid-liquid extraction mode

Simulation studies were carried out, in an unsteady state, for the removal of ammonia from water via a membrane contactor. The contactor had an aqueous solution of NH(3) in the lumen and sulphuric acid in the shell side. The model equations were developed considering radial and axial diffusion and convection in the lumen. The partial differential equations were converted by the finite difference technique into a series of stiff ordinary differential equations w.r.t. time and solved using MATLAB. Excellent agreement was observed between the simulation results and experimental data (from the literature) for a contactor of 75 fibres. Excellent agreement was also observed between the simulation results and laboratory-generated data from a contactor containing 10,200 fibres. Our model is more suitable than the plug-flow model for designing the operation of the membrane contactor. The plug-flow model over-predicts the fractional removal of ammonia and was observed to be limited when designing longer contactors.