Numerical Study of the Erosion of an Immersed Tube in a Bubbling Fluidized Bed

The erosion of internals in fluidized beds is a problem that still holds the attention of researchers. The main reasons are the complexity of the process itself and the difficulties in defining the variables involved in the process. The multiple possible situations depending on the geometry, particle characteristics and fluidization parameters embiggens the problem.

Several experimental and numerical studies have analysed the erosion on immersed tubes in fluidized beds. Most of the published papers during the 70’s, 80’s and 90’s were focused in fluidized bed combustors and there is no studies on new fluidized bed applications, such as Concentrating Solar Power (CSP) applications, with novel particles as SiC, which are very hard and sharp. Regarding numerical simulations, it is highlighted the use of Multiphase Particle in Cell Method (MP-PIC), which considers group of particles with the same properties instead of individual particles.

The aim of this paper is to perform a numerical simulation of a 2-D single tube in a fluidized bed in Barracuda Virtual Reactor (v. 22.1) to predict the erosion in the perimeter of the tube. The numerical results are compared with previous studies (Xu et al. in 2022). Different grid size and time steps are analysed.

The numerical results clearly shows that the erosion of the tube is not homogeneous along the circumference of round tubes, being higher on the lower lateral areas of the tube and minimum on the top, where the particles are at rest. The plot of the erosion versus the circumferential position typically shows an inverted W-shape, with a relative minimum at the tube bottom (although the erosion remains high).