Research and diagnosis of local slagging in boilers based on impact signal

In view of widespread slagging on heating surfaces of boilers in power plants， the paper introduces a piezoelectric acceleration sensor for slag impact signal measurement to determine the size and position of the impact of slag on the water wall of the cold ash hopper. In order to verify the accuracy of the method， the slag on boiler water wall was simulated in a laboratory. By the symmetric arrangement of the acceleration sensors in four positions of the cold ash hopper， the four vibration starting times and the maximum amplitudes were measured to judge the fallen slag's approximate area. Moreover， the impact coefficient between the slag block and the cold ash hopper was obtained by calculation fitting. Finally， a sensor was installed in a boiler for on-site test in a power plant. The results show that the method can well locate and measure the slag mass.