Numerical simulation of growing Cu particles in a Kenics static mixer reactor in which Cu²⁺ is reduced by carbohydrates

Numerical simulations of the mixing of copper ions (Cu(II)) and growing particles have been performed in the range of Re 10-1000 in a vertical (down-flow) Kenics static mixer reactor. The growth of the particles is based on the local Cu(II) concentration and determines the reduction rate of the Cu(II) concentration, which is solved with a finite volume code. The particles are tracked using a code that solves the BBO equation and the flow is solved using a Lattice Boltzmann code. It was found that the Kenics static mixer enhances the mixing of Cu(II). However, at low Reynolds numbers (Re < 500) the particles are not well mixed, which has a negative influence on the particle size distribution (PSD). Furthermore, in a pipe (without a mixer) the PSD is more narrow than in a Kenics static mixer reactor, but the Cu(II) concentration is not well mixed in a pipe, which slows down the reduction process. Results indicate that a high Reynolds number is necessary to mix both the particles and Cu(II) concentration in the Kenics static mixer.