Experimental study on ash deposition characteristic of convection heating surface in waste heat boiler

The major factors effecting on the ash deposition, concentration of ash, gas velocity, ash feature and arrangement of tubes, have been investigated through the model experiment of ash deposition. It is discovered that the concentration of ash particles in gas only affects the relaxation time of reaching stable state, Under the condition of low gas velocity, the deposition quantity increases with gas velocity increasing, contrast to the condition that the gas velocity is higher than 5 m/s. The effect of ash diameters distribution on ash deposition is obvious, and small particles are easy to deposit in the eddy zone of tube bundle. In contrast, large particles are difficult to deposit. The arrangement style of tubes is important for ash deposition, and deposition of in-line arrangement is severer than that of staggered-arrangement. The deposition quantity increases with tube diameters increasing. Under the condition of low gas velocity the ash deposition increases with the tubes step, but gradually decreases after velocity reaching 5.7 m/s.