Deposition Model of Fouling on Coal-fired Utility Boiler Heating Surfaces

According to the real flow field condition, a new particle-granules collision deposition model for fly ash particles in boilers flue was proposed, which considered the granular material mechanical properties and surface morphology of pre-deposited medium. Through the analysis of deposition characteristics for the oblique collision of particle with pre-deposited medium, both the tangential and the normal sub-models were established, and the criteria of critical sticking angle and critical rebound velocity were also produced. A case study of the impact for copper particle with granular medium was given, whose results were basically consistent with experiment data. A computation fluid dynamics(CFD) simulation of fouling deposition on some economizer tubes was implemented to demonstrate the validity of proposed deposition model. In this simulation, the distribution of deposition and fouling morphology were also reconstructed.