Patent Application
20080022907
For the purpose of illustrating the invention, the drawings show a form of the invention that is presently preferred. However, it should be understood that the present invention is not limited to the precise arrangements and instrumentalities shown in the drawings, wherein:
Referring now to the drawings in which like reference numerals indicate like parts, and in particular, to
System 120 is typically located in an area of an SCR that is prone to build-up of dust 123, e.g., see
Referring now to FIGS. 4 and 5A-5C, end nozzle 136 may have a mushroom cap 137, an angled end 138, a perforated end 139, or an open end 140 to direct compressed air 141 in a particular direction. Mushroom cap 137 is configured to direct compressed air 141 flowing upwardly through lance 134 downwardly to a surface of duct 124 (see arrows). Angled end 138 is configured to direct compressed air 141 flowing upwardly through lance 134 in a particular direction, e.g., laterally (see arrows). Perforated end 139 is configured to direct compressed air 141 flowing upwardly through lance 134 in a particular direction, e.g., laterally. Open end 140 is configured to direct compressed air 141 flowing upwardly through lance 134 in a particular direction, e.g., upwardly. Mushroom cap 137, angled end 138, perforated end 139, and open end 140 may be configured, e.g., include screens or appropriately sized opening, to help prevent dust 123 from entering lance 134. It is contemplated that each type of end nozzle 136 may be adjustable or movable in myriad directions, e.g., telescopically, rotationally, vertically, horizontally, laterally, axially, etc. Plurality of lances 134 within a single sub-header 132 may include any combination of different types of end nozzles 136. Alternatively, as illustrated in
Referring now to
In use, air from compressor 126 is sent to an air injection header 128. Air injection header 128 feeds sub-headers 132 that in turn, feed air into injection lances 134. Lances 134 extend into duct 124 through holes 130. The number of lances 134 may vary depending on the size of the SCR system. Each sub-header 128 typically feeds multiple injection lances 134. At the end of each injection lance 134 is typically a nozzle 136. Air exiting each nozzle 136 causes dust 123 in the area of nozzle 136 to fluidize and become re-entrained in the flue gas flowing through duct 124.
The use of a compressed air system to eliminate ash deposition in an SCR system offers advantages over prior art designs in that it eliminates dust avalanches from falling onto the catalyst and plugging it. The present invention has the advantage of compressed air being an inexpensive medium and readily available. Maintenance needs for air compressors are well known, easy to perform, and inexpensive. Additionally, because the nozzle design and header arrangement can be customized for plant specific requirements, aspects of the present invention may be easily modified.
Although the invention has been described and illustrated with respect to exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto, without parting from the spirit and scope of the present invention. Accordingly, other embodiments are within the scope of the following claims.
