Effect of anti-wear beams on waterwall heat transfer in a CFB boiler

To install multi-stage anti-wear beams on waterwall is an effective method to protect against the erosion in a CFB boiler. However, it changes the gas-solid flow and heat transfer on the waterwall. For a clear understanding, this paper used a numerical method to analyze the effect of anti-wear beams on the wall heat transfer in a 330 MW CFB boiler. The gas-solid hydrodynamics in furnace was simulated based on the TFM and EMMS drag model, and the heat transfer characteristic was obtained by cluster renewal model. The results showed that the anti-wear beams would make the descending solid flow to be multi-staged with lower speed on waterwall. Not only the heat transfer area but also the heat transfer coefficient was decreased. Thus, the furnace heat absorption was reduced by about 5.5%, and the average temperature would rise by up to 30 °C after installing the beams. Moreover, the operation parameters have an effect on the wall heat transfer at the upper furnace, while minor effect on the middle and lower part. It can be explained by the protection of two adjacent anti-wear beams, which provide a relatively stable circumstance for solid descending flow and heat transfer.