The microwave attenuation method is one of the common methods for online measurement of carbon content in fly ash in recent years. However

due to the differences in sampling locations and sampling devices of the fly ash

there is a large uncertainty in particle size of the fly ash

which results in a large error in the measurement of carbon content in fly ash. The existing carbon content fitting models are all based on the relationship between the attenuation of the characteristic frequency signal by fly ash and the carbon content of fly ash

which has problems such as large error and poor adaptability. In order to solve these problems

this paper proposes to use the time-domain main peak attenuation of the signal instead of the attenuation of the signal at the eigenfrequency as a method for online fitting of the carbon content in fly ash. To correct the error caused by the uncertainty of fly ash particle size

the effects of fly ash with different particle size ranges on the measurement of ash level and fly ash carbon content are compared on the basis of the study on ash level and carbon content measurement. The results show that

the peak attenuation of the signal in the time domain is used to calculate the carbon content

and the results are in good agreement with the actual values. For the same mass of ash samples in the waveguide

the particle size of the fly ash does not have any significant effect on the measurement accuracy of the ash level. When the microwave method is applied to measure the carbon content in the fly ash in the waveguide

for the same mass of ash samples

the attenuation of the fly ash on the microwave signal inside the waveguide decreases gradually with the particle size of the fly ash. Thus

the measured value of carbon content increases as the particle size of the fly ash decreases.