Evolutionary Changes in Furnace Combustion Conditions Which Affect Ash Deposition in Modern Boilers
Extensive literature and research results are availible which are directed at analyzing or predicting the tendency of coal ash to deposit in radiant furnaces and onto convective surfaces. However, these results are generally based upon conventional pulverized coal (PC) furnace designs,combustion systems, and fuels utilized over the last 40 years. Such conventional systems are being supplanted on some new units by combustion systems designed to respond to recent changes in the market place.
Some recent changes in the market which ultimately affect the furnace combustion processes can be cited. Environmental laws have placed greater importance on reducing emissions of NOx, CO, SO2 and air toxics. Similarly, there is some political support to reduce global emissions of CO2 and N2O, and one response has been the introductory commercial usage of PC-based combined cycles. And finally, there is an increase in the practice of world sourcing for coal supplies for a single power station, leading to the need to design a single furnace to reliably combust as many as 20 disparate fuels. This trend may accelerate in Pacific Rim nations due to the reduction in imported fuel tariffs associated with recent open trade agreements.
Deep staging, substochiometric combustion
Rotating dynamic classsifiers
Individual coal burner flame analyzers
World sourcing of coal supplies
Fully fired (hot windbox) combined cycles, with and without pyrolysis
Preheating of coal-air mixture upstream of burner nozzle
Miscellaneous effects (waterwall tube orientation, indirect bin fired system, water deslaggers)
KeywordsBurner Zone Unburned Carbon Coal Supply Stage Combustion Waterwall Tube
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- 1).Fiveland, W., et al, “ An Efficient Method for Predicting Unburned Carbon in Boilers”, Comb.Sci.andTech.,V81 no4–6, 1992, p147–167Google Scholar
- 2).Marcus,H., “Grosse Dampferzeuger mit Steinkohlen-Staubfeuerung und Trockenentaschung”, Energie und Technik, Heft 7 /8, 1974, p179–186Google Scholar
- 3).Singh, B.,“Pulverized Fuel Size Distribution Influence in a Power Generating Utility Boiler”, proc. 1994 ACTC Workshop on the Impact of Coal Quality on Power Plant Performance,Brisbane, Australia, 15May94.Google Scholar
- 4).Miyamae,S., et al, “Nox and unburned Carbon Simulation Technologies on Pulverized Coal firing Boiler”, IHI Eng. Rev.,V20no2 Apr87,p56–60Google Scholar
- 5).Hashimoto,H., et al, “Developement of a Flame Diagnostic System for a coal-firing Boiler”, ASME paper 92-JPGC-EC-2, presented at the IJPGC conference, Atlanta, 18Oct92.Google Scholar
- 6).Kehr, M. et al, “800MW Brown coal fired Steam Generator Schwarze Pumpe”,17May94 PowerGen conference, Cologne, Germany, Penwell Pub, Houston, Tx.Google Scholar
- 7).Bennert,J.,“Auslegungskriterion fur grosse Steinkohleblocke”,VDI-Berichte, Nr454,1982,p95101Google Scholar
- 8).Joyce, J. S. “How Gas Turbines can Improve the Efficiency and Environmental Compatability of new and old Steam Power Plants”, Proc. ASME-JSME Int Conf on Pow Eng(ICOPE-93),Sept 1993(Tokyo)p469–474.Google Scholar
- 9).Termuehlen, H.,et al, “Repowering Existing Power Stations with Heavy Duty Gas Turbines-An Economical Approach”, Proc. PowerGen, 5th int’l Conf, Orlando, 1992,v11p235–244.Google Scholar