The Babcock & Wilcox Company

Babcock & Wilcox Power Generation Group, Inc.

Kevin J Rogers

Wadie F Gohara

Fred C Owens, Ii

Dennis W Johnson

Dennis K McDonald

Steven Feeney

Robert B Myers

Melvin John Albrecht

William Downs

Ralph T Bailey

Ted V Mull, Jr

Michael G Varner

Mark S Bock

Seyed B Ghorishi

Kenneth F Hoover

An in-situ forced oxidation wet flue gas desulfurization apparatus, method and arrangement for utilization with oxy-fuel combustion power plants. The apparatus is a tower-like structure having a flue gas scrubbing zone and a reaction zone located subjacent to the gas scrubbing zone. A sulfur oxide absorbing liquid slurry is supplied to the gas scrubbing zone to react with and scrub the sulfur oxides from the flue gas. The partially reacted liquid slurry reagent and the scrubbed products drain into the reaction zone, rising to a set level. Oxidation air is introduced into the liquid slurry in the reaction zone to force the in-situ oxidation of sulfur compounds collected in the reaction zone. A wall separates and communicates the gas scrubbing zone and the reaction zone, the wall prevents the oxidation air from entering the gas scrubbing zone and extends into the liquid slurry below a nominal depth required to establish and maintain a liquid slurry seal thereby substantially precluding the leakage of flue gas into the reaction zone while allowing the partially reacted liquid slurry reagent and scrubbed products to drain into the reaction zone.

Segregated in-situ forced oxidation wet flue gas desulfurization for oxygen-fired fossil fuel combustion

An apparatus for low-temperature NO-reduction is disclosed, which is useful in boiler installations used at electric-generating plants. The apparatus employs one or a plurality of moving-bed reactors wherein a moving bed of common base-metal catalyst is used for selective catalytic reduction of NOpresent in flue gas. The moving bed permits continuous introduction of fresh or regenerated catalyst, thus obviating the conventional problems of sulfur-poisoning and consequent reduction in catalytic activity with such catalysts. Due to the lower activation energies of such catalysts, an SCR utilizing the moving-bed reactors disclosed herein can be located downstream of the air heater, further improving electric-generating efficiency. Methods for low-temperature NOreduction are also disclosed.

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A device for channeling boiler flue gas flow and injecting controlled amounts of ammonia upstream of a selective catalytic reduction (SCR) NOremoval 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-NOmole ratio control.

Channelized SCR inlet for improved ammonia injection and efficient NOx control

An integrated air foil and ammonia injection grid provides a plurality of air foils across a flue conveying flue gas. Each air foil has a leading curved edge and a tapered, pointed, trailing end. At least one injection pipe is positioned inside each air foil, and has at least one nozzle for injecting ammonia into the flue gas flowing across the air foils. Preferably, plural injection tubes are provided and positioned one behind the other in each air foil, and each injection tube in a given air foil has a length different than a length of the other injection tubes in the same air foil. A longest injection tube in a given air foil is located furthest downstream and proximate the tapered trailing edge and a shortest injection tube in the same air foil is located furthest upstream, remaining injection tubes in the same air foil being progressively shorter the further upstream any injection tube is located. Apertures may be provided on opposed lateral sides of the air foils for introducing a gas flow into the flue gas passing across the air foils. Ammonia flow to each injection pipe may be individually controlled.

Integrated air foil and ammonia injection grid for SCR systems

An apparatus to mix a slurry mixture with an oxidization air within a reaction tank of a wet scrubber spray tower of a flue gas desulfurization system for a furnace. The apparatus improves the contact between forced oxidization air and slurry mixture within the reaction tank.

Apparatus for mixing a tank and improving air/liquid contact in an

A system and method for distributing, injecting, and dispersing a sorbent mixture of sorbent and compressed filtered flue gas into the combustion furnace portion of a boiler furnace. Prior to injection into the combustion furnace, the sorbent mixture is heated with steam and distributed within the combustion furnace through a plurality of injection tubes having their ends arranged in a grid and oriented substantially toward the combustion furnace flue gas flow.

Apparatus for the injection distribution and dispersion of sorbent in a

An integrated spray header tray assembly (18) for a wet flue gas desulfurization spray tower (10) wherein a series of spray headers (22) having opposed nozzles (26) for desulfurizing spray are located along a perforated plate (24) acting as one set of baffles (30) while a second set of baffles (32) positioned perpendicularly thereto forms a baffled tray with the perforated plate (24) and headers (22) while allowing the introduction of desulfurizing spray from the header nozzles (22) parallel to the perforated tray (24).

Spray header integrated tray

A method of forced oxidation flue gas desulfurization uses an oxidation air system air stream to not only provide oxidation air into an absorber vessel, but also to pneumatically convey and inject dry reagent into the absorber vessel to satisfy reagent addition requirements. If necessary, other dry additives can be added to the dry reagent so that the oxidation air stream injects both the dry reagent and the dry additives into the absorber vessel. The dry additives can be added in this method even if the reagent is introduced by other known methods.

Method of reagent and oxidation air delivery

A method of forced oxidation flue gas desulfurization uses an oxidation air system air stream to not only provide oxidation air into an absorber vessel, but also to pneumatically convey and inject dry reagent into the absorber vessel to satisfy reagent addition requirements. If necessary, other dry additives can be added to the dry reagent so that the oxidation air stream injects both the dry reagent and the dry additives into the absorber vessel.

A method and apparatus for recycling the bottoms product from an absorber tower back to the absorber tower. However, before the bottoms product is returned to the tower, the solid particles entrained therein are removed via one or more centrifuges closely coupled to the absorber tower. These centrifuges are located adjacent the tower and are elevated with respect to the tower such that their centrate can be directly returned or delivered back to the absorber tower via gravity.

Direct centrate/filtrate return

A process of beneficiation of a dry flue gas desulfurization end product into separate dry particle streams dependant upon particle size, density, or shape. Further refinement of the dry end product is accomplished by initially comminuting the end product prior to classification by size, density, or shape.

Beneficiation of dry scrubber product

A process of purifying the gypsum slurry end product produced by a flue gas desulfurization process which incorporates fine solids separation/classifying, dewatering, mixing, and filtering to both achieve a useful gypsum product and to recycle as much process water as possible to the flue gas desulfurization process. This purification process separates the incoming gypsum slurry into a fine solids stream containing a disproportionate amount of impurities therein that are concentrated and subsequently disposed of and a coarse solids stream containing a large amount of gypsum therein from which a usable gypsum product is recovered.

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Wadsworth, OH, United States of America

Kevin J Rogers