Abstract: A system for fluidizing ash in a duct of a selective catalytic reduction system. The system includes a duct, a source for generating compressed air, and an air injection header joined with the source and joined with the duct via one or more holes in the duct. The air injection header is adapted to inject compressed air from the source to the areas of the duct prone to dust build-up. The air injection header includes a sub-header joined with a plurality of injection lances. Each of the plurality of injection lances has an end nozzle. The end nozzle may have a mushroom cap or an angled end configuration to direct air in a particular direction.

Abstract: Systems and processes for treating a flue gas for removing sulfur oxides (SOx) entrained in the flue gas generally includes contacting the gas stream with an aqueous alkali and/or alkaline earth metal hydroxide solution such as sodium hydroxide and reacting SOx entrained in the gas stream to form an aqueous alkali and/or alkaline earth metal sulfur-containing salt solution such as sodium sulfate. The aqueous alkali and/or alkaline earth metal sulfur-containing salt solution can be introduced into an electrodialysis apparatus configured to electrolyze water to form hydrogen and hydroxyl ions that selectively combine with alkali and/or alkaline earth metal ions and sulfur containing ions from the aqueous alkali and/or alkaline earth metal sulfur containing salt feedstream to form a regenerated alkali and/or alkaline earth metal hydroxide feedstream and an acid containing feedstream.

Abstract: One embodiment described herein relates to a system for removing pollutants from a flue gas. The system includes a selective catalytic reduction (SCR) system having a SCR reactor containing a NOx reducing catalyst and one or more SCR protective devices. At least one of the SCR protective devices is connected to a rapping hammer system that actively remove fly ash collected on the SCR protective devices.

Abstract: One embodiment described herein relates to a system for removing pollutants from a flue gas. The system includes a selective catalytic reduction (SCR) system having a SCR reactor containing a NOx reducing catalyst and one or more SCR protective devices. At least one of the SCR protective devices is connected to a rapping hammer system that actively remove fly ash collected on the SCR protective devices.

Abstract: One aspect of the invention relates to a method for removing contaminants from a flue gas stream (22). The method includes: removing fly ash from a flue gas stream (22) utilizing a particle collector (24); contacting the flue gas stream with an alkaline reagent in a wet scrubber (26); discharging a purge liquid (30) from the wet scrubber (26); and, combining at least a portion of the purge liquid with at least a portion of fly ash circulating within a dry circulating fluid bed scrubber (48) to form moistened fly ash (60).

Abstract: A system for separating sulfur dioxide from a gas using an aqueous absorption liquid. The system includes a housing, an apertured plate, an outlet box, a distribution mechanism, a container, and a pump. The housing has an inlet and an outlet. The apertured plate is positioned between the inlet and the outlet and includes a lower side, an upper side, and apertures fluidly connecting the lower and upper sides. The outlet box includes a distribution mechanism that is arranged so that the absorption liquid draining from the outlet box contacts the gas from the inlet before the gas passes through the apertures in the apertured plate. The container contains the absorption liquid and is fluidly connected with the housing. The pump draws the absorption liquid from the container through the pump and through a conduit to the upper side of the apertured plate.

Abstract: One aspect of the invention relates to a method for removing contaminants from a flue gas stream (22). The method includes: removing fly ash from a flue gas stream (22) utilizing a particle collector (24); contacting the flue gas stream with an alkaline reagent in a wet scrubber (26); discharging a purge liquid (30) from the wet scrubber (26); and, combining at least a portion of the purge liquid with at least a portion of fly ash circulating within a dry circulating fluid bed scrubber (48) to form moistened fly ash (60).

Abstract: One aspect of the invention relates to a method for removing contaminants from a flue gas stream (22). The method includes: removing fly ash from a flue gas stream (22) utilizing a particle collector (24); contacting the flue gas stream with an alkaline reagent in a wet scrubber (26); discharging a purge liquid (30) from the wet scrubber (26); combining at least a portion of the purge liquid (30) with at least a portion of the fly ash (48) to form moistened fly ash (60); and injecting at least a portion of the moistened fly ash (60) into the flue gas stream (22) upstream of the particle collector (24), whereby the moistened fly ash (60) removes at least a portion of contaminants present in the flue gas stream (22).

Abstract: A system for separating sulfur dioxide from a gas using an aqueous absorption liquid. The system includes a housing, an apertured plate, an outlet box, a distribution mechanism, a container, and a pump. The housing has an inlet and an outlet. The apertured plate is positioned between the inlet and the outlet and includes a lower side, an upper side, and apertures fluidly connecting the lower and upper sides. The outlet box includes a distribution mechanism that is arranged so that the absorption liquid draining from the outlet box contacts the gas from the inlet before the gas passes through the apertures in the apertured plate. The container contains the absorption liquid and is fluidly connected with the housing. The pump draws the absorption liquid from the container through the pump and through a conduit to the upper side of the apertured plate.

Abstract: One embodiment described herein relates to a system for removing pollutants from a flue gas. The system includes a selective catalytic reduction (SCR) system having a SCR reactor containing a NOx reducing catalyst and one or more SCR protective devices. At least one of the SCR protective devices is connected to a rapping hammer system that actively remove fly ash collected on the SCR protective devices.

Abstract: A process for cleaning a flue gas stream (10) in a flue gas cleaning system (2) to remove contaminants such as particulates and acidic components therefrom. The process includes admitting the flue gas stream to a particle collection device (18) to deposit the contaminants onto collector surfaces (19) therein, contacting the collector surfaces (19) with a wash water (20) to remove the contaminants therefrom, and discharging the wash water from the particle collection device (18) to a position downstream of the particle collection device (18). The discharged wash water is neutralized and circulated within the flue gas cleaning system (2).

Abstract: A system for fluidizing ash in a duct of a selective catalytic reduction system. The system includes a duct, a source for generating compressed air, and an air injection header joined with the source and joined with the duct via one or more holes in the duct. The air injection header is adapted to inject compressed air from the source to the areas of the duct prone to dust build-up. The air injection header includes a sub-header joined with a plurality of injection lances. Each of the plurality of injection lances has an end nozzle. The end nozzle may have a mushroom cap or an angled end configuration to direct air in a particular direction.

Abstract: One aspect of the invention relates to a method for removing contaminants from a flue gas stream (22). The method includes: removing fly ash from a flue gas stream (22) utilizing a particle collector (24); contacting the flue gas stream with an alkaline reagent in a wet scrubber (26); discharging a purge liquid (30) from the wet scrubber (26); combining at least a portion of the purge liquid (30) with at least a portion of the fly ash (48) to form moistened fly ash (60); and injecting at least a portion of the moistened fly ash (60) into the flue gas stream (22) upstream of the particle collector (24), whereby the moistened fly ash (60) removes at least a portion of contaminants present in the flue gas stream (22).

Abstract: A device for channeling boiler flue gas flow and injecting controlled amounts of ammonia upstream of a selective catalytic reduction (SCR) NOx removal system. A perforated plate and/or damper can be located within one or more channels to provide volumetric control through a channel. Flow conditioning devices such as static mixing tabs and/or flow straightening tube bundles can optionally be included in each channel to improve mixing and velocity profiles. Gas flow rate measurements made, for example via pressure taps, within one or more channels can be used to measure flow and provide feedback for improved ammonia-to-NOx mole ratio control.

Abstract: A device for channeling boiler flue gas flow and injecting controlled amounts of ammonia upstream of a selective catalytic reduction (SCR) NOx removal system. A perforated plate and/or damper can be located within one or more channels to provide volumetric control through a channel. Flow conditioning devices such as static mixing tabs and/or flow straightening tube bundles can optionally be included in each channel to improve mixing and velocity profiles. Gas flow rate measurements made, for example via pressure taps, within one or more channels can be used to measure flow and provide feedback for improved ammonia-to-NOx mole ratio control.

Abstract: An outage protection system for a SCR (selective catalytic reduction) reactor utilizes a pair of dampers to isolate the catalyst bed and the ammonia injection grid of the SCR reactor and to provide a blower driven closed loop flow of externally heated air from the injector grid across the catalyst bed to an external heater and back to the injection grid.

Abstract: A system is disclosed for minimizing equipment and flue fouling for any boiler, turbine, or combustion process in which heat recovery is advantageous and pollutant removal is necessary. The process uses an SCR located upstream of a condensing heat exchanger and maintains the temperatures in the flue gas duct such that ammonia slip and ammonium salt products are collected only on the heat exchanger surfaces which are periodically washed with water and this wash water being collected.