Modeling and simulation of juice clarifier using computational fluid dynamics for enhanced sugar quality

Abstract

Over the past few decades modern technologies have been developed and adopted to improve sugarcane processing. These improvements have not only reduced operating and production costs but have also helped increase productivity and profitability. Separation in a flotation clarifier is performed by generating adequate bubbles and sustaining a suitable environment for these bubbles to adhere to the impurities to be removed. Due to the presence of air, the density of flocs formed by mixing bubbles and impurities is lower than that of liquids. Buoyancy causes the flocs to surge to the surface, forming a layer of scum that is relatively easy to remove. A clarifier used in a sugar factory has a unilateral discharge. There is a ring inside, with 24 2-inch-diameter holes. Because the outlet is one-sided, the control is not ideal. This study presents the outcomes attained from a numerical analysis of the full-scale flow in a clarifier. The results were validated by comparing the numerical results with experimental results. The average flow rate from the four outlets of the proposed geometry was 2399 kg/h, with an error of less than 1% compared with base case geometry. The main governing equations used during simulations of the juice clarifier were the continuity equation and the momentum equation commonly known as Navier–Stokes equations. The turbulent modeling approach standard k–ε was adopted. The values of k and ε are calculated using turbulence kinetic energy (k) equation and dissipation rate (ε) equations, respectively.