Electric Power Research Institute Incorporated

Epri

Wate T Bakker

Anthony Facchiano

Yoshiatsu Sawaragi

Roger N Johnson

Robert R Hardman

Edward L Courtright

Shigemitsu Kihara

Richard A Brown

Yozo Hayase

The invention provides a method which includes the step of locating a burner of a low NOx boiler that produces a disproportionately high quantity of unburned carbon. The air-to-fuel ratio at the burner is then increased to decrease the percentage of unburned carbon attributable to the burner. The air-to-fuel ratio at a second burner of the low NOx boiler is reduced to maintain a substantially constant total air-to-fuel ratio in the low NOx boiler.

Method for reducing unburned carbon in low NOx boilers

A method to reduce waterwall corrosion in a low NO.sub.x boiler includes the steps of locating a waterwall area of a low NO.sub.x boiler where oxidizing conditions exist and deposition of FeS is likely. The combustion air input at the waterwall area is biased to reduce FeS deposition on the waterwall. The biased combustion air input increases the oxidation rate of FeS.sub.2 so as to reduce FeS deposition on the waterwall. The biased combustion air input may be achieved by increasing the air-to-fuel ratio of one burner while reducing the air-to-fuel ratio of another burner, such that the overall air-to-fuel ratio in the low NO.sub.x boiler is substantially constant.

Method for reducing waterwall corrosion in low NO.sub.x boilers

A thermal barrier coating has several different layers, the first of which is an oxidation barrier. A phonon scattering zone is positioned on top of the oxidation barrier. The phonon scattering zone includes a plurality of phonon scattering interface layers, each of which is formed between a first ceramic material and a second ceramic material. The first and second ceramic materials are each between 1 and 1000 nanometers thick. An optical reflectance zone is positioned on the phonon scattering zone. The optical reflectance zone includes a second stack of ceramic materials with a plurality of optically reflecting interface layers, each of which is formed between a first ceramic material and a second ceramic material. The first and second ceramic materials are each between 0.1 and 1.0 microns thick.

Multilayer nanostructured ceramic thermal barrier coatings

High-vanadium austenitic alloys, which are structurally stable and have improved corrosion resistance in wet corrosive environments and high-temperature corrosion resistance in reducing atmosphere, contain Ni by 33.0 to 60.0 weight %, Cr by 23.0 to 28.0 weight %, V by 2.4 to 5.0 weight %, C by 0.10 weight % or less, N by 0.05 weight % or less, Si by 0.35% weight % or less, Al by 0.5 weight % or less, Mn by 1.5% weight % or less, P by 0.020 weight % or less, S by 0.005 weight % or less, and one or more selected from the group consisting of B by 0.0010 to 0.010 weight %, Zr by 0.010 to 0.06 weight %, Ti by 0.03 to 0.50% weight %, and Nb by 0.05 to 1.0 weight %, the balance being Fe and impurities.

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Saratoga, CA, United States of America

Wate T Bakker