Abstract:

Coal ash deposit is important to the heat transfer of ultra-supercritical boilers. Its radiation characteristics are very important for accurately describing the heat transfer in the boiler. Based on the Fourier transform infrared spectroscopy (FTIR), a high-temperature normal spectral emissivity measurement platform was established. The platform can measure radiation of 3-14μm wavelengths and 373-873K temperatures. The measurement results for the platform were calibrated with standard samples. The emissivity of artificial ash samples was measured. The artificial ash emissivity has a remarkable spectral distribution characteristic, which is lower in the short wavelength and higher in the long wavelength. As the temperature rises, the artificial ash spectral emissivity increases. As the Fe₂O₃ content increases, the spectral emissivity of the overall artificial ash sample rises in the full spectrum.

Key words: coal ash deposit, ultra-supercritical boilers, spectral emissivity, FTIR