Task 3.15 -- Impacts of low-NOx combustion on fly ash and slagging. Semi-annual report, July 1--December 31, 1996
With the advent of the Clean Air Act Amendments of 1990, the coal-fired power industry began a more accelerated move toward using low-NOx burner (LNB) technologies to reduce NOx emissions. Most LNBs incorporate less oxygen with the coal initially, creating a cooler and somewhat substoichiometric initial combustion zone, with additional oxygen added further on in the combustion process to complete char combustion. Another method used to achieve lower NOx emissions is to fire the coal substoichiometrically and add additional air through overfire air ports. Both of these methods create certain impacts on fireside performance that are different from conventional high-excess-air firing arrangements. Some of the impacts that have been noticed by the utility industry are higher levels of unburned carbon in the fly ash and bottom ash, increased boiler tube corrosion, higher particulate loadings on control devices, and changes in slagging in the main furnace. Work on the fundamental mechanisms of entrained ash and ash deposit formation during low-NOx combustion has been sparse. This project by the Energy and Environmental Research Center (EERC) focuses on the issues of entrained ash formation and slagging for low-NOx combustion systems in general. Time-resolved combustion tests under conventional and low-NOx conditions have been conducted to note particle-size formation and slagging deposition. The results from this work are yielding an increased understanding of the mechanisms of ash formation during low-NOx combustion along with methods for enhancing heat transfer and fly ash collectability. Specific objectives of this research project include (1) determining whether initial char and ash generated under low-NOx conditions have greater tendencies for slagging than conventionally generated ash and (2) determining the differences, if any, between particle size and composition for entrained ash generated under low-NOx and conventional combustion conditions.
- Research Organization:
- North Dakota Univ., Energy and Environmental Research Center, Grand Forks, ND (United States)
- Sponsoring Organization:
- USDOE Assistant Secretary for Fossil Energy, Washington, DC (United States)
- DOE Contract Number:
- FC21-93MC30097
- OSTI ID:
- 634174
- Report Number(s):
- DOE/MC/30097-5587; ON: DE97002234; TRN: AHC2DT01%%185
- Resource Relation:
- Other Information: PBD: Aug 1997
- Country of Publication:
- United States
- Language:
- English
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