Abstract: A method of predicting a nitrogen oxide (NOx) emission rate of a non-continuous, natural gas-fired boiler is presented. The method includes: calculating a correlation of the NOx emission rate to a measured fuel flow rate and a sampled oxygen (O2) concentration based on a plurality of sampled NOx emission concentrations, measured fuel flow rates, and sampled (O2) concentrations during operation of the non-continuous, natural gas-fired boiler using a computing device; calculating a predicted NOx emission rate based on the correlation with the measured fuel flow rate and the sampled O2 concentration using the computing device; and providing the predicted NOx emission rate for use by a user.

Abstract: A method of predicting a nitrogen oxide (NOx) emission rate of a non-continuous, natural gas-fired boiler is presented. The method includes: calculating a correlation of the NOx emission rate to a measured fuel flow rate and a sampled oxygen (O2) concentration based on a plurality of sampled NOx emission concentrations, measured fuel flow rates, and sampled (O2) concentrations during operation of the non-continuous, natural gas-fired boiler using a computing device; calculating a predicted NOx emission rate based on the correlation with the measured fuel flow rate and the sampled O2 concentration using the computing device; and providing the predicted NOx emission rate for use by a user.

Abstract: A slurry coating composition is described, which is very useful for enriching the surface region of a metal-based substrate with aluminum. The composition includes colloidal silica and particles of an aluminum-based powder, and is substantially free of hexavalent chromium. The slurry may include colloidal silica and an alloy of aluminum and silicon. Alternatively, the slurry includes colloidal silica, aluminum or aluminum-silicon, and an organic stabilizer such as glycerol. The slurry exhibits good thermal and chemical stability for extended periods of time, making it very useful for industrial applications. Related methods and articles are also described.

Abstract: An organic coating composition is described, which can be used to enrich the surface region of a metal-based substrate with aluminum. The composition comprises an aluminum-based powder and at least one organic resin, e.g., alkyds, epoxies, or silicone materials. At least some of the aluminum-based powder is in the form of substantially spherical powder particles. The coating composition is substantially free of hexavalent chromium. It can be applied to the substrate by a variety of techniques, such as spraying. It is then heat-treated, to cause diffusion of aluminum into the surface region of the substrate, e.g., a turbine engine component. The composition exhibits good thermal and chemical stability for extended periods of time. Related articles are also described.

Abstract: An organic coating composition is described, which can be used to enrich the surface region of a metal-based substrate with aluminum. The composition comprises an aluminum-based powder and at least one organic resin, e.g., alkyds, epoxies, or silicone materials. At least some of the aluminum-based powder is in the form of substantially spherical powder particles. The coating composition is substantially free of hexavalent chromium. It can be applied to the substrate by a variety of techniques, such as spraying. It is then heat-treated, to cause diffusion of aluminum into the surface region of the substrate, e.g., a turbine engine component. The composition exhibits good thermal and chemical stability for extended periods of time. Related articles are also described.

Abstract: A slurry coating composition is described, which is very useful for enriching the surface region of a metal-based substrate with aluminum. The composition includes colloidal silica and particles of an aluminum-based powder, and is substantially free of hexavalent chromium. The slurry may include colloidal silica and an alloy of aluminum and silicon. Alternatively, the slurry includes colloidal silica, aluminum or aluminum-silicon, and an organic stabilizer such as glycerol. The slurry exhibits good thermal and chemical stability for extended periods of time, making it very useful for industrial applications. Related methods and articles are also described.