Computational fluid dynamics simulation of an Inert Particles Spouted Bed Reactor (IPSBR) system

Abstract

<jats:title>Abstract</jats:title><jats:p>A novel system for contacting gases and liquids, suitable for many applications involving gas–liquid contact such as CO<jats:sub>2</jats:sub> capture and brine desalination, has been simulated and experimentally validated. The system comprises a vertical vessel with gas and liquid ports and inert particles that enhance mixing and provide a high gas–liquid interfacial area. A low gas flow rate was statistically demonstrated and experimentally verified to be the optimum condition for CO<jats:sub>2</jats:sub> capture and brine desalination; however, the gas velocity can have a considerable effect on the motion of inert particles inside the reactor. Uniform particles motion ensures good mixing within the reactor and hence efficient absorption and stripping process. A computational fluid dynamics (CFD) model, namely Eulerian model, presented in this paper, will help demonstrate the effect of mixing particles at specific conditions on the gas and liquid velocities inside the reactor, gas and liquid volume distribution through reactor, and eddy viscosities stresses of the mixing particles. A mesh-independent study was conducted to demonstrate the independency of mesh structure and size on the output responses. A quasi-steady state was attained to ensure the stability and feasibility of the selected model. The assembled model exhibits remarkable applicability in determining the optimum mixing particles densities, volume ratios, and sizes to ensure best velocity distribution and gas spreading inside the reactor and accordingly enhance the associated chemical reactions.</jats:p>

CFD and statistical approach to optimize the average air velocity and air volume fraction in an inert-particles spouted-bed reactor (IPSBR) system

“…The IPSBR [ 5 ] has an internal diameter of 78 mm and an overall height of 700 mm. It was operated in a semi-batch mode, where the liquid was exposed to a continuous flow of gas through an orifice with a specific diameter.…”

“…The details of the governing equations used to describe the flow in the contact system are shown as follows [ 5 , 20 , 21 ]:…”

“…The inert particles used in the contact system previously [ 1 ] were made of polymethyl methacrylate with an average particle diameter of 0.013 m, density of 1020 kg/m 3 , surface area of 4.92 cm 2 /particle, and sphericity of 1.0; these particles were also used in the present study. In the discrete phase model, the trajectory of the particles was tracked using the Newtonian equation of motion [ 5 , 22 ]: where is the resistance impacting on a unit-mass particle and represents the air resistance impacting on the particle where is the fluid velocity, is the particle velocity, is the fluid molecular viscosity, is the fluid density, is the particle density, and is the particle diameter. Re is the relative Reynolds number, which is defined as …”

“…They reported significant impact of the inert particle mixing on carbon dioxide uptake, achieving an optimum update of 0.2 g CO 2 /g BHD at 24°C temperature and 1 atm pressure. A previous study simulated the hydrodynamics of this reactor (IPSBR) using a transient two-dimensional (2-D) axisymmetric model via computational fluid dynamics (CFD) with coupled Eulerian and discrete phase model (CFD-DPM) [ 5 ]. Turbulence was simulated by the standard k-ϵ mixture model, and DPM was applied to consider the effect of mixing particles.…”

“…RSM has also been reported to be more effective in revealing the factors that most strongly contribute to the regression coefficient and in identifying insignificant quadratic terms. The main objective of the present work is to optimize the hydrodynamic parameters of the IPSBR [ 1 , 2 , 5 ]. CFD simulation has been combined with RSM to study the effect of the feed-gas velocity, orifice diameter, gas head, diameter of mixing particles, and the mixing particles loading on the average air velocity distribution and gas volume fraction in the IPSBR.…”