THERMAL SCIENCE

International Scientific Journal

AIR STAGING APPLICATION EFFECTS ON OVERALL STEAM BOILER OPERATION

ABSTRACT
This paper presents the results of calculation system of main processes in power steam boiler, before and after application of air staging. Modified air injection scheme was implemented during 2015 on the power steam boiler within unit 1 of TPP Kostolac B. Measurements performed on site showed that applied reconstruction led to a permanent loss of the steam boiler power. This study was performed in order to define the cause of such an occurrence and to consider the possibility for regaining the designed steam parameters along with keeping NOx concentration in prescribed limits. This paper discusses the influence of repositioning the air injection location on processes within the furnace. Furthermore, the influence of the redistribution of injected airflow along the furnace height on important boiler operation parameters has been analyzed. Analysis showed that, with appropriate dosing of air along the height of the existing furnace, it is possible to achieve the optimum of the boiler’s operation parameters. Results of research showed that air staging throughout the furnace height in best test case additionally reduces NOx concentration (195/225 mg/Nm3) and increases the power of considered boiler (828.8/751.1 MW) with an insignificant decrease of the boiler’s efficiency (86.27/86.77 %). Furthermore, the designed temperatures of superheated (540/498 °C) and reheated (540/518 °C) steam have been reached again, whereby the safety of the boiler’s operation has been significantly increased. Results of this study improve the present explanation of the processes occurred in the furnace with applied primary measures. They also give directions on defining the most influential parameters on considered processes with the final purpose to increase the efficiency and availability of the entire plant. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR-33018: Increase in energy and ecology efficiency of processes in pulverized coal-fired furnace and optimization of utility steam boiler air preheater by using in-house developed software tools]
KEYWORDS
PAPER SUBMITTED: 2018-04-13
PAPER REVISED: 2019-04-24
PAPER ACCEPTED: 2019-05-08
PUBLISHED ONLINE: 2019-07-06
DOI REFERENCE: https://doi.org/10.2298/TSCI180413286S
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2019, VOLUME 23, ISSUE Supplement 5, PAGES [S1559 - S1574]
REFERENCES
  1. Government of the Republic of Serbia, The Energy Development Strategy of the Republic of Serbia until 2025 with projections to 2030 (in Serbian).
  2. EIA, International Energy Outlook 2013, 2013.
  3. U.S. Energy Information Administration, Annual Energy Outlook 2015 with projection to 2040, 2015.
  4. Directive 2010/75/EU of the European Parliament and of the Council of 24 November 2010 on industrial emissions (integrated pollution prevention and control)
  5. Hill, S.C., Smoot, L.D., Modeling of nitrogen oxides formation and destruction in combustion systems, Progress in Energy and Combustion Science, 26 (2000) 417-458.
  6. Heinsohn, R.G., Kabel, R.L., Sources and Control of Air Pollution, Prentice - Hall, New Jersey, 1999.
  7. Tobin, D., et. al., Application of Layered Control Technologies to Significantly Reduce NOx Emissions from Coal-Fired Boilers, GE Energy, 2nd U.S.-China NOx Workshop Dalian, China, 2005.
  8. Zhuikov, A.V., Reduction of nitrogen oxides in boiler furnaces, Journal of Siberian Federal University Engineering & Technologies, 6 (2011) 620-628 (in Russian).
  9. Stupar, G., Modeling of processes in utility steam boiler with air staging, Ph. D. thesis, University of Belgrade, Belgrade, Serbia, 2016 (in Serbian).
  10. Yang, J. H., et. al., Effects of detailed operating parameters on combustion in two 500-MWe coal-fired boilers of an identical design, Fuel, 144 (2015) 145-156.
  11. Asotani, T., et. al., Prediction of ignition behavior in a tangentially fired pulverized coal boiler using CFD, Fuel, 87 (2008) 482-490.
  12. Li, Z., et. al., Combustion and NOx emission characteristics of a retrofitted down-fired 660 MWe utility boiler at different loads, Applied Energy, 88 (2011) 2400-2406.
  13. Liu, G., et. al., Effect of the anthracite ratio of blended coals on the combustion and NOx emission characteristics of a retrofitted down-fired 660-MWe utility boiler, Applied Energy, 95 (2012) 196-201.
  14. Wang, J., et. al., The effect of air staged combustion on NOx emissions in dried lignite combustion, Energy, 37 (2012) 725-736.
  15. Liu, G., et. al., Numerical simulations of flow, combustion characteristics, and NOx emission for down-fired boiler with different arch-supplied over-fire air ratios, Applied Thermal Engineering, 75 (2015) 1034-1045.
  16. Tian, F., et. al., Numerical modeling of Victorian brown coal combustion in a tangentially fired furnace, Energy Fuels, 24 (2010) 4971- 4979.
  17. Zeng, L., et. al., Numerical simulation of combustion characteristics and NOx emissions in a 300 MWe utility boiler with different outer secondary-air vane angles, Energy Fuels, 24 (2010) 5349-5358.
  18. Stupar, G., et. al., Assessing the impact of primary measures for NOx reduction on the thermal power plant steam boiler, Applied Thermal Engineering, 78 (2015) 397-409.

© 2024 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence