Spectroscopic research on infrared emittance of coal ash deposits
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2009
Authors
Saljnikov, AleksandarVučićević, Biljana
Komatina, Mirko
Gojak, Milan
Goričanec, Darko
Stevanović, Zoran
Article (Published version)
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This paper deals with thermal radiation characteristics of ash deposits on a pulverized coal combustion boiler of an electric power plant. Normal emittance spectra in the near to medium infrared (2.5-25 mu m) region and total normal emittances were measured on four kinds of ground ash deposits. Measurements were conducted in the 570-1460 K temperature range which is common for boiler furnaces, by both heating and cooling the ash samples, with the aim to study the effect of their thermal history. Dependence of emittance on wavelength, temperature and chemical composition was studied, too. Samples were tested for transparency (opacity) to verify the accuracy of results. It was determined that the thicknesses used for the ash powders are opaque for infrared radiation for thicknesses in the order of a millimeter. Tests have shown that spectral emittance increases with an increase of wavelength with a characteristic pattern common for all samples. Spectral normal emittance increases strongl...y with temperature at shorter wavelengths and remains high and unchanged at longer ones. Emittance spectra are not very sensitive to chemical composition of ashes especially beyond lambda approximate to 5 mu m. With an increase of temperature, total emittance of the powdered sample decreases to a minimum value around 1200 K. Further temperature rise induces an increase of total emittance due to sintering in the ash. On cooling, the emittance increases monotonically following the hysteresis. Quantitative directions for evaluating thermal radiation characteristics of ash deposits for the merits of the safety design of boiler furnaces were proposed. That comprises correlating the experimentally obtained emittance spectra with curves of simple analytical form, i.e., a continuous function of minimum emittance vs. wavelength. The proposed method can be extended to other specimens from the same furnace and used to determine correlations for thermal calculation of old and design of new furnaces - with similar geometry and combusting similar coal. The method is potentially applicable to completely different boiler furnaces combusting different coal, and the authors recommend running the tests with new deposit samples. The data will then be applicable to the thermal design of a whole new class of furnaces, having similar geometry and combusting similar coal. This is expected to greatly enhance the accuracy and precision of thermal calculation as well as the efficiency of thermal design of steam boilers.
Keywords:
Spectroscopy / Heat radiation / Emittance / Boiler furnace / Ash depositSource:
Experimental Thermal and Fluid Science, 2009, 33, 8, 1133-1141Publisher:
- Elsevier Science Inc, New York
Funding / projects:
- Ministry of Education, Science and Technology of Japan [01200058]
DOI: 10.1016/j.expthermflusci.2009.07.002
ISSN: 0894-1777
WoS: 000270920100001
Scopus: 2-s2.0-69849106398
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Mašinski fakultetTY - JOUR AU - Saljnikov, Aleksandar AU - Vučićević, Biljana AU - Komatina, Mirko AU - Gojak, Milan AU - Goričanec, Darko AU - Stevanović, Zoran PY - 2009 UR - https://machinery.mas.bg.ac.rs/handle/123456789/939 AB - This paper deals with thermal radiation characteristics of ash deposits on a pulverized coal combustion boiler of an electric power plant. Normal emittance spectra in the near to medium infrared (2.5-25 mu m) region and total normal emittances were measured on four kinds of ground ash deposits. Measurements were conducted in the 570-1460 K temperature range which is common for boiler furnaces, by both heating and cooling the ash samples, with the aim to study the effect of their thermal history. Dependence of emittance on wavelength, temperature and chemical composition was studied, too. Samples were tested for transparency (opacity) to verify the accuracy of results. It was determined that the thicknesses used for the ash powders are opaque for infrared radiation for thicknesses in the order of a millimeter. Tests have shown that spectral emittance increases with an increase of wavelength with a characteristic pattern common for all samples. Spectral normal emittance increases strongly with temperature at shorter wavelengths and remains high and unchanged at longer ones. Emittance spectra are not very sensitive to chemical composition of ashes especially beyond lambda approximate to 5 mu m. With an increase of temperature, total emittance of the powdered sample decreases to a minimum value around 1200 K. Further temperature rise induces an increase of total emittance due to sintering in the ash. On cooling, the emittance increases monotonically following the hysteresis. Quantitative directions for evaluating thermal radiation characteristics of ash deposits for the merits of the safety design of boiler furnaces were proposed. That comprises correlating the experimentally obtained emittance spectra with curves of simple analytical form, i.e., a continuous function of minimum emittance vs. wavelength. The proposed method can be extended to other specimens from the same furnace and used to determine correlations for thermal calculation of old and design of new furnaces - with similar geometry and combusting similar coal. The method is potentially applicable to completely different boiler furnaces combusting different coal, and the authors recommend running the tests with new deposit samples. The data will then be applicable to the thermal design of a whole new class of furnaces, having similar geometry and combusting similar coal. This is expected to greatly enhance the accuracy and precision of thermal calculation as well as the efficiency of thermal design of steam boilers. PB - Elsevier Science Inc, New York T2 - Experimental Thermal and Fluid Science T1 - Spectroscopic research on infrared emittance of coal ash deposits EP - 1141 IS - 8 SP - 1133 VL - 33 DO - 10.1016/j.expthermflusci.2009.07.002 ER -
@article{ author = "Saljnikov, Aleksandar and Vučićević, Biljana and Komatina, Mirko and Gojak, Milan and Goričanec, Darko and Stevanović, Zoran", year = "2009", abstract = "This paper deals with thermal radiation characteristics of ash deposits on a pulverized coal combustion boiler of an electric power plant. Normal emittance spectra in the near to medium infrared (2.5-25 mu m) region and total normal emittances were measured on four kinds of ground ash deposits. Measurements were conducted in the 570-1460 K temperature range which is common for boiler furnaces, by both heating and cooling the ash samples, with the aim to study the effect of their thermal history. Dependence of emittance on wavelength, temperature and chemical composition was studied, too. Samples were tested for transparency (opacity) to verify the accuracy of results. It was determined that the thicknesses used for the ash powders are opaque for infrared radiation for thicknesses in the order of a millimeter. Tests have shown that spectral emittance increases with an increase of wavelength with a characteristic pattern common for all samples. Spectral normal emittance increases strongly with temperature at shorter wavelengths and remains high and unchanged at longer ones. Emittance spectra are not very sensitive to chemical composition of ashes especially beyond lambda approximate to 5 mu m. With an increase of temperature, total emittance of the powdered sample decreases to a minimum value around 1200 K. Further temperature rise induces an increase of total emittance due to sintering in the ash. On cooling, the emittance increases monotonically following the hysteresis. Quantitative directions for evaluating thermal radiation characteristics of ash deposits for the merits of the safety design of boiler furnaces were proposed. That comprises correlating the experimentally obtained emittance spectra with curves of simple analytical form, i.e., a continuous function of minimum emittance vs. wavelength. The proposed method can be extended to other specimens from the same furnace and used to determine correlations for thermal calculation of old and design of new furnaces - with similar geometry and combusting similar coal. The method is potentially applicable to completely different boiler furnaces combusting different coal, and the authors recommend running the tests with new deposit samples. The data will then be applicable to the thermal design of a whole new class of furnaces, having similar geometry and combusting similar coal. This is expected to greatly enhance the accuracy and precision of thermal calculation as well as the efficiency of thermal design of steam boilers.", publisher = "Elsevier Science Inc, New York", journal = "Experimental Thermal and Fluid Science", title = "Spectroscopic research on infrared emittance of coal ash deposits", pages = "1141-1133", number = "8", volume = "33", doi = "10.1016/j.expthermflusci.2009.07.002" }
Saljnikov, A., Vučićević, B., Komatina, M., Gojak, M., Goričanec, D.,& Stevanović, Z.. (2009). Spectroscopic research on infrared emittance of coal ash deposits. in Experimental Thermal and Fluid Science Elsevier Science Inc, New York., 33(8), 1133-1141. https://doi.org/10.1016/j.expthermflusci.2009.07.002
Saljnikov A, Vučićević B, Komatina M, Gojak M, Goričanec D, Stevanović Z. Spectroscopic research on infrared emittance of coal ash deposits. in Experimental Thermal and Fluid Science. 2009;33(8):1133-1141. doi:10.1016/j.expthermflusci.2009.07.002 .
Saljnikov, Aleksandar, Vučićević, Biljana, Komatina, Mirko, Gojak, Milan, Goričanec, Darko, Stevanović, Zoran, "Spectroscopic research on infrared emittance of coal ash deposits" in Experimental Thermal and Fluid Science, 33, no. 8 (2009):1133-1141, https://doi.org/10.1016/j.expthermflusci.2009.07.002 . .