Patent Application
20080308128
1. Field of the Invention
The invention disclosed herein relates to combustion systems and, in particular, to preparation and inspection of waterwall systems.
2. Description of the Related Art
Combustion systems make use of a variety of devices for generation of steam and moving that steam. One such combustion system is a boiler. In a furnace of some boilers, is a “waterwall.” The waterwall typically lines the walls of the furnace and includes a plurality of tubes that are welded together. During operation, the tubes carry water (i.e., coolant) into the furnace where combustion takes place. The heat of combustion is transferred to the waterwall and steam is generated within the tubes. As one might imagine, in such a harsh environment, the tubes are subject to degradation. Accordingly, system operators conduct periodic inspections of the tubes to ensure efficient operation.
Referring now to
In operation, crushed fuel (e.g., coal) and sorbent (e.g., limestone) are fed to a lower portion of the combustor 2 as bed material. Primary air is supplied to a bottom portion of the combustor 2 through an air distributor, with secondary air fed through one or more elevations of air ports in a lower portion of the combustor 2.
Combustion takes place throughout the combustor 2, which is filled with the bed material. Flue gas and entrained solids leave the combustor 2 as combustor exhaust through a gas outlet 7.
In typical embodiments, the combustor 2 generally includes two regions. A lower portion and an upper portion. The lower portion of the combustor 2 includes the fuel, a primary air distributor, secondary air ports, fuel feed ports and solids recycle ports. The density of the bed in this region it relatively high on average and typically highest at the elevation of the air distributor. The density then drops off with increasing height of the combustor 2. Physically, the lower portion is usually rectangular, tapered and formed from finned or fusion welded water-wall tubing 15. The lower portion is typically lined with refractory to protect the water-wall tubing 15.
In this simplified illustration, the water-wall tubing 15 is supplied boilerwater (e.g., water, water with certain chemicals, etc, . . . ) by an inlet header 17. The inlet header 17 provides the boilerwater for steam generation in the water-wall tubing 15 of the combustor 2.
The upper portion of the combustor 2 is usually rectangular with vertical walls, where the walls are formed with finned or fusion welded water-wall tubing 15. The upper portion is typically unlined to maximize heat transfer to the water-wall tubing 15. The walls of the combustor 2 are cooled by circulation in the water-wall tubing 15.
Still referring to
As one might surmise, having an efficient combustion system calls for including as great a surface area as possible with the water-wall tubing 15. In some embodiments, the surface area of the water-wall tubing 15 is up to about 7,000 square meters (m2).
Typically, inspection of the water-wall tubing 15 is performed about once a year. In order to do so, extensive cleaning is required. Cleaning and inspection requires erection of scaffolding and often at least ten (10) days for completion.
Therefore, what are needed are improved cleaning and inspection techniques for evaluation of water-wall tubing. Preferably, the techniques provide for reduced labor and time savings.
Disclosed is an automated cleaning and inspection system including: movement components for moving the system along water-wall tubing disposed in a combustor, cleaning components for cleaning the water-wall and inspecting components for inspecting the water-wall; wherein the moving, cleaning and inspecting are coordinated for automated performance.
Also disclosed is a computer program product stored on machine readable media, the product including instructions for performing automated cleaning and inspection of water-wall tubing disposed within a combustor, the instructions including instructions for: coordinating movement of the system in relation to the water-wall tubing; cleaning of the water-wall tubing; and inspecting the water-wall tubing.
In addition, a method for cleaning and inspecting water-wall tubing disposed on an interior surface of a combustor is disclosed and includes: selecting an automated system for cleaning and inspecting water-wall tubing; disposing the automated system into a relationship with the water-wall tubing; and initiating operation of the automated system.
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
Disclosed are methods and apparatus providing for automated cleaning and inspection of water-wall tubing 15 of a Steam Generation System (SGS) 10. One skilled in the art will recognize that a variety of systems and designs may make use of the water-wall tubing 15. Accordingly, these systems and designs fall within the scope of a SGS 10 as described herein.
As discussed herein, the term “automated” makes reference to performance of a task, such as cleaning or inspection, without continuous supervision or intervention by an operator. Accordingly, the term “manual” generally makes reference to tasks that are performed step by step or directly by an operator or laborer. It is considered that semi-automated performance, such as performance of a task with periodic supervision or intervention, falls within the realm and meaning of the term “automated.”
As used herein, it is considered that the automated system 100 is useful for at least one of cleaning and inspection of water-wall technology implemented in most any embodiment of a combustor 2 or combustion chamber.
In general, the water-wall tubing 15 includes a plurality of tubes for carrying water (i.e., coolant, which may include water and other chemicals, such as corrosion and erosion inhibitors). The water-wall tubing 15 is disposed along interior portions of a combustion chamber.
Refer now to
In
The processing resources 150 may include components such as a processor, memory, storage, an interface, a power supply, a bus, an input, an output, a connection, an interface and other such components. In this embodiment, the processing resources 150 provides a user with the user interface 160. The user interface 160 is useful for various tasks including at least one of programming, monitoring, directing, calibrating, positioning, starting and shutting down of the automated system 100. In some embodiments, these tasks are performed, at least in part, by computer implemented instructions.
In some embodiments, the automated performance of moving, cleaning and inspecting is performed according to computer implemented instructions executed in the processing resources 150. In other embodiments, the processing resources 150 do not exist as such. Stated another way, in some embodiments, the automated system 100 is a “dumb” system that follows a prescribed routine once the automated system 100 is started. For example, once the automated system is turned on, it progresses in one direction performing cleaning or inspecting until redirected (such as by actuation of a sensor).
Of course, the various components of each module may appear in another module or serve multiple uses. Accordingly, the embodiment of
In typical embodiments, external apparatus provide for assistance in movement or operation of the automated system 100. Reference may be had to the exemplary embodiment of
The automated system 100 is typically adapted for use in a variety of systems implementing water-wall technology. That is, the automated system 100 is not limited to flat water-walls, horizontal implementations nor vertical implementations of water walls.
Typically, at least for the embodiment of
The location information may be derived by mechanical apparatus (such as by tracking revolutions of wheels along the rails) or by various electronic apparatus (such as by triangulation with wireless systems, or optical range finders). These and other types of distance measuring equipment as are known in the art may be used.
Various other techniques for deployment may be used. For example, deployment may be by a “scissors lift” deployed on a floor of the combustor, by a crane above, any by other techniques as known to one skilled in the art.
In some embodiments, the automated system 100 is programmed for one of determining and following a cleaning or inspection protocol. For example, the automated system 100 may be programmed for 100 percent coverage of the water-wall tubing 15. In other embodiments, the automated system 100 performs at least one of cleaning and inspection according to statistical tests. In further embodiments, the automated system 100 is loaded with maintenance information and historical data. The automated system 100 may determine likely failure points and perform inspection, or additional inspections, at the failure points. The automated system 100 is typically equipped to be responsive to hold points or other predetermined conditions. For example, the automated system 100 may at least temporarily terminate operation under certain conditions, issue an alarm, communicate, such as by sending an SMS message (e.g., issuing a test result code) or perform some other such task.
Of course, more than one automated system 100 may be used at a time. That is multiple units may be used to reduce cleaning and inspection time. In some embodiments, one unit performs cleaning while a secondary unit follows and performs inspection. In typical embodiments, use of the automated system 100 provides for a substantial reduction in outage time (for example, about ninety percent).
Typically, the automated system 100 is equipped for high temperature operation. That is, the automated system is adapted for use during a cool-down cycle in the combustor 2, prior to such temperatures as where manual inspection could normally occur.
One skilled in the art will recognize that a great number of mechanical, electromechanical, electrical, optical and other such devices may be used advantageously with the automated system 100 and in support of at least one of cleaning and inspection of water-wall tubing 15.
In support of the teachings herein, various analysis components may be used, including digital and/or an analog components, such as for providing system control. The components may have sub-components such as a processor, storage media, memory, input, output, communications links, user interfaces, software programs, signal processors (digital or analog) and other such components (such as resistors, capacitors, inductors and others) to provide for operation and analyses of the apparatus and methods disclosed herein in any of several manners well-appreciated in the art. It is considered that these teachings may be, but need not be, implemented in conjunction with a set of computer executable instructions stored on a computer readable medium, including memory (ROMs, RAMs), optical (CD-ROMs), or magnetic (disks, hard drives), or any other type that when executed causes a computer to implement the method of the present invention. These instructions may provide for equipment operation, control, data collection and analysis and other functions deemed relevant by a system designer, owner, user or other such personnel, in addition to the functions described in this disclosure.
While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications will be appreciated by those skilled in the art to adapt a particular instrument, situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
