2D dynamic mesh model for deposit shape prediction in boiler bank of recovery boiler with different tube spacing arrangements

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.CFD tools are essential in the design and operation of boilers. One particular aspect that can be modelled by CFD is the deposition and plugging in heat transfer surfaces of boilers. Fouling and slagging are the most typical causes of unscheduled boiler shutdowns. This is why appropriate predictions of deposition geometries and rates are of high interest. Among other applications, CFD Multiphase approaches are capable of modelling particle-laden streams. However, the relatively large number of models to select, each one with its own properties, typical applications, benefits and drawbacks- creates difficulties when trying to determine which model to use at first approach. The problem that we are going to tackle is of a really complicated and multidisciplinary nature (thermo-fluid mechanics, sticking/rebounding of particles, sintering, among others). Dynamic mesh capabilities in commercial CFD software packages are able to modify the interphase fluiddeposit according to the growth rate, assuming it has been accurately calculated by a convenient multiphase model for particle-laden flows. In this work, such a CFD model for prediction of deposition shapes in a classical boiler bank of a Kraft Recovery Boiler will be developed and presented. The effect of tube transversal spacing will also be analyzed