Unburned carbon in the circulating fluidised bed boiler fly ash

• Authors: Rafał Kobyłecki
• Languages of publication: EN

Abstracts

EN

The paper describes the results of various actions and industrial tests conducted in order to decrease the content of unburned carbon in the fly ash of a circulating fluidised bed combustor (CFBC). Several attempts to improve the situation were made and the effects of several parameters on the unburned carbon content in the fly ash were investigated (e.g. bed temperature, cyclone separation efficiency, fuel particle size distribution, boiler hydrodynamics, grid design, and fuel data). Unfortunately, no satisfactory solution to these problems was found. Probably, apart from attrition and char fragmentation, additional factors also contributed to the formation of unburned carbon in the CFBC fly ash.

Keywords

EN

CFB boiler; fly ash; unburned carbon; coal combustion

• Publisher: De Gruyter Open
• Journal: Chemical and Process Engineering
• Year: 2011
• Volume: 32
• Issue: 4
• Pages: 255-266

Dates

published

1 - 12 - 2011

online

9 - 11 - 2011

Contributors

author

Rafał Kobyłecki

• Department of Energy Engineering, Częstochowa University of Technology, ul. Brzeźnicka 60a, 42-200 Częstochowa, Poland

References

• Anthony E.J., Bulewicz E.M., Jia, L., 2007. Reactivation of limestone sorbents in FBC for SO2 capture. Prog. Energy Combust. Sci., 33, 171-210. DOI: 10.1016/j.pecs.2006.10.001.[Crossref]
• Batra V.S., Urbonaite S., Svensson G., 2008. Characterization of unburned carbon in bagasse fly ash. Fuel, 87, 2972-2976. DOI: 10.1016/j.fuel.2008.04.010.[Crossref][WoS]
• Bis Z., Kobyłecki R., Olas M., 2004. Methodology to determine the concentration of unburnables and unburned carbon in fluidized bed boiler fly ashes. Report No. DPZU-04-592-669, Czestochowa University of Technology (in Polish).
• Brown R.C., Dykstra J., 1995. Systematic errors in the use of loss-on-ignition to measure unburned carbon in fly ash. Fuel, 74, 570-574. DOI: 10.1016/0016-2361(95)98360-Q.[Crossref]
• Dong N., 2011. Utilisation of low rank coals. IEA Report, CCC/182.
• Fan M., Brown R.C., 2001. Comparison of the loss-on-ignition and thermogravimetric analysis techniques in measuring unburned carbon in coal fly ash. Energy Fuels, 15, 1414-1417. DOI: 10.1021/ef0100496.[Crossref]
• Hower J.C., Senior C.L., Suuberg E.M., Hurt R.H., Wilcox J.L., Olson E.S., 2010. Mercury capture by native fly ash carbons in coal-fired power plants. Prog. Energy Combust. Sci., 36, 510-529. DOI: 10.1016/j.pecs.2009.12.003.[WoS][Crossref]
• Kobyłecki R., Andrzejczyk M., Bis Z. 2005. Large-scale CFB boiler with different cyclone separation efficiencies - Operational experiences and analysis. Proc. of the 8th International Conference on Circulating Fluidized Beds, CFB 8. Hangzhou, China, 10-13 May 2005, 978-985.
• Kobyłecki R., Czabowski D., Bis Z., 2008. Unburnts in large-scale CFBC fly ashes - effect of fuel type and bed hydrodynamics. Proc. of the 9th International Conference on Circulating Fluidized Beds, CFB-9. Hamburg, Germany, 13-16 May 2008, 523-528.
• Kobyłecki R., Nowak W., Bis Z., Rogóż J., 2010. 460MWe supercritical once-through two-phase CFB boiler - First operational experiences. The Fifth International Topical Team Workshop on Two-Phase Systems for Ground and Space Applications. Kyoto, Japan, 26-29 September 2010, 85.
• Kulaots I., Hurt R.H., Suuberg E.M., 2004. Size distribution of unburned carbon in coal fly ash and its implications. Fuel, 83, 223-230. DOI: 10.1016/S0016-2361(03)00255-2.[Crossref]
• Lee J.-M., Kim J.-S., Kim J.-J., 2003. Evaluation of the 200MWe Tonghae CFB boiler performance with cyclone modification. Energy, 28, 575-589. DOI: 10.1016/S0360-5442(02)00155-X.[Crossref]
• Li H., Shen X.-Z., Sisk B., Orndorff W., Li D., Pan W.-P., Riley J.T., 1997. Studies of fly ash using thermal analysis techniques. J. Therm. Anal., 49, 943-951. DOI: 10.1007/BF01996780.[Crossref]
• Liu H., Tan H., Gao Q., Wang X., Xu T., 2010. Microwave attenuation characteristics of unburned carbon in fly ash. Fuel, 89, 3352-3357. DOI: 10.1016/j.fuel.2010.02.029.[WoS][Crossref]
• Paya J., Monzo J., Borrachero M.V., Perris E., Amahjour F., 1998. Thermogravimetric methods for determinimg carbon content in fly ashes. Cement Concr. Res., 28, 675-686. DOI: 10.1016/S0008-8846(98)00030-1.[Crossref]
• Scott D., Nilsson P.-A., 1999. Competitiveness of future coal fired unites in different countries. IEA Report, CCC/14.
• Smith I., Nalbandian H., 2000. Industrial coal use - prospects for emissions reduction. IEA Report, CCC/38.
• Styszko-Grochowiak K., Gołas J., Jankowski H., Kozinski S., 2004. Characterization of the coal fly ash for the purpose of improvement of industrial on-line measurement of unburned carbon content. Fuel, 83, 1847-1853. DOI: 10.1016/j.fuel.2004.03.005.[Crossref]
• Tang M.-S., X. Li, D.-C. Liu, 1999. Operating experience of 75t/h two stage circulating fluidized bed boiler. 15th International Conference on Fluidized Bed Combustion. Savannah, USA, 9-13 May 1999, 35.
• Wang Z., Yu W., Bo S., 2010. Startup, commissioning and operation of Fenyi 100MW CFB boiler. 20th International Conference on Fluidized Bed Combustion. Xi'an, China, 18-20 May 2009, 137-142. DOI: 10.1007/978-3-642-02682-9_15.[Crossref]
• Waller D.J., Brown R.C., 1996. Photoacoustic response of unburned carbon in fly ash to infrared radiation. Fuel, 75, 1568-1574. DOI: 10.1016/0016-2361(96)00125-1.[Crossref]

Identifiers

DOI

10.2478/v10176-011-0020-8