Effect of metal anti-wear device on the water wall erosion in CFB boiler

Abstract

The erosion of water wall tube induced by the flushing of ash is one of the safest factors in the operation of the circulating fluidized bed (CFB) boiler. The reasonable installation of a metal anti-wear device on the water wall provides an effective protection method for reducing particle erosion on the wall surface. Seven metal anti-wear devices were designed and evaluated by comparing the erosion distribution of the local water wall surface in this work. The results show the type with an angle between the windward side and the water wall greater than 90° and the leeward side perpendicular to the water wall can obtain a good anti-wear effect. The erosion rate of water wall increases correspondingly with the increasing inlet velocity and particle size, but decreases to some extent by adding cohesive particles. The height of the ash deposition zone decreases correspondingly with the decreasing particle diameter and proportion of cohesive particles. The type G metal anti-wear device was preferably applied and tested in a CFD boiler for half a year according to its simple structure and its behavior of reducing erosion rates. The Type G anti-wear device can well protect the water wall of CFB boilers at the power plants.