EP0213380B1 - Soot blower - Google Patents

Soot blower Download PDF

Info

Publication number
EP0213380B1
EP0213380B1 EP86110284A EP86110284A EP0213380B1 EP 0213380 B1 EP0213380 B1 EP 0213380B1 EP 86110284 A EP86110284 A EP 86110284A EP 86110284 A EP86110284 A EP 86110284A EP 0213380 B1 EP0213380 B1 EP 0213380B1
Authority
EP
European Patent Office
Prior art keywords
soot
tube
blowing
wall
heat
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP86110284A
Other languages
German (de)
French (fr)
Other versions
EP0213380A2 (en
EP0213380A3 (en
Inventor
Georg Ziegler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ABB Management AG
Original Assignee
Gebrueder Sulzer AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Gebrueder Sulzer AG filed Critical Gebrueder Sulzer AG
Publication of EP0213380A2 publication Critical patent/EP0213380A2/en
Publication of EP0213380A3 publication Critical patent/EP0213380A3/en
Application granted granted Critical
Publication of EP0213380B1 publication Critical patent/EP0213380B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J3/00—Removing solid residues from passages or chambers beyond the fire, e.g. from flues by soot blowers
    • F23J3/02—Cleaning furnace tubes; Cleaning flues or chimneys
    • F23J3/023—Cleaning furnace tubes; Cleaning flues or chimneys cleaning the fireside of watertubes in boilers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
    • F22B1/18—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines
    • F22B1/1838—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines the hot gas being under a high pressure, e.g. in chemical installations
    • F22B1/1846—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines the hot gas being under a high pressure, e.g. in chemical installations the hot gas being loaded with particles, e.g. waste heat boilers after a coal gasification plant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28G—CLEANING OF INTERNAL OR EXTERNAL SURFACES OF HEAT-EXCHANGE OR HEAT-TRANSFER CONDUITS, e.g. WATER TUBES OR BOILERS
    • F28G1/00—Non-rotary, e.g. reciprocated, appliances
    • F28G1/16—Non-rotary, e.g. reciprocated, appliances using jets of fluid for removing debris
    • F28G1/166—Non-rotary, e.g. reciprocated, appliances using jets of fluid for removing debris from external surfaces of heat exchange conduits

Definitions

  • the invention relates to a soot blower for a heat exchanger surface, which consists of parallel tubes which carry a cooling medium and are welded together to form a wall.
  • Such a sootblower is known from CH-PS 648 397.
  • the sootblower tube is coaxially surrounded by a tube of the heat exchanger surface so that cooling medium flows in the space between the two tubes and protects the sootblower tube against excessive temperatures.
  • this solution which is good in itself, has the disadvantage that the outlet temperature of the cooling medium from the double tube is influenced by the temperature of the soot blowing medium and therefore deviates from the outlet temperature of the cooling medium emerging from the other tubes of the heat exchanger surface.
  • this object is achieved in that at least one protective tube connected to the heat exchanger surface is arranged on the side of the wall exposed to the heat and in front of the sootblower tube, through which the same cooling medium flows as the heat exchanger surface, and that the nozzle is located between the Protective tube and the wall extends.
  • the protective tube arranged in front of the sootblast tube is exposed to practically the same thermodynamic conditions as the other tubes of the heat exchanger surface, so that the outlet temperature of the cooling medium from the protective tube and that from the other tubes of the heat exchanger surface are essentially the same.
  • the sootblower has good accessibility to the sootblower tube during assembly and for any repairs, and - depending on the need - the nozzles or their number can be changed in a simple manner.
  • a second heat exchanger surface 2 which also has the shape of an eight-sided regular prism 2, consists of a plurality of vertical wall tubes 3 ′ and webs 7 ′ welded to one another. It surrounds the prism of the heat transfer surface I coaxially and is rotated by 22.5 ° with respect to the inner prism. At their lower ends in FIG.
  • the wall pipes 3 open into an octagonal horizontal distributor 31 and at their upper ends into a collector 31 'which is the same as the distributor 31 and is arranged parallel to the latter.
  • the wall pipes 3 ' open at the bottom in a distributor 32 and at the top in a collector 32', the distributor 32 and the collector 32 'likewise being octagonal and identical to one another and arranged parallel to one another.
  • the collectors 31 ', 32' are at the same height, whereas the outer distributor 32 is arranged lower than the inner distributor 31.
  • the heat exchanger surfaces 2 and 2 are tightly welded to the associated distributor 31 or 32 and the associated collector 31 'or 32'.
  • the distributors 31, 32 are connected to at least one water source, not shown, and the collectors 31 ', 32' to at least one steam consumer, not shown.
  • Hot synthesis gas which flows in the direction of arrow 20 from top to bottom through the inner prism, then flows around its distributor 31 (arrows 20 ') and then rises between the inner prism and the outer prism.
  • the synthesis gas gives off heat to the water in the wall pipes 3 and 3 ', steam being generated.
  • the heat exchanger surfaces I and 2 are accommodated with their distributors 31 and 32 and collectors 31 'and 32' in a common pressure vessel 10, in which the pressure is largely the same.
  • a sootblower tube 4 is provided, which can be fed with the aid of a control valve 8 with a compressed gas acting as a sootblowing medium from at least one compressed gas source, not shown.
  • a protective tube 6 is arranged in front of each sootblower tube 4 and parallel to it, which ends at the bottom in the distributor 31 and at the top in the collector 31 '.
  • the protective tubes have the same diameter as the wall tubes 3 and are made of the same material as this. They protect the sootblast pipes 4 from excessive temperatures and are subject to similar thermodynamic conditions as the wall pipes 3, so that the steam content of the water-steam mixture emerging from them is approximately equal to that of the mixture emerging from the wall pipes 3.
  • a plurality of sheet metal pieces 16 connect each protective tube 6 to the two nearest wall tubes 3.
  • nozzles 5 are provided which extend between the protective tube 6 and the wall tubes 3, namely through the gaps between two sheet metal pieces 16.
  • the nozzles one Blower tube 4 are directed alternately against the next but one side of the inner prism, so that the inner surface of each side of this prism is swept from two sides by compressed gas (FIG. 2).
  • all pipes are accessible from at least one wall side, which is favorable both for assembly and for repairs.
  • sootblast tubes 14 are provided in each octagon side of the outer heat exchanger surface 2, each taking the place of a web 7 '.
  • Two of the blowpipes 14 are provided in the central region of the side, and the nozzles 15 of the blowpipe 14 located on the left of the center are directed towards the outside of the inner prism provided on the right of the center; Accordingly, the nozzles 15 of the blowpipes 14 located on the right of the center are directed towards the outside of the inner prism, which extends to the left of the center.
  • the two remaining sootblast tubes 14 on each outer prism side are attached near the edges of this prism. Their nozzles 15 are each directed towards the side of the outer prism adjacent to the associated edge.
  • the function of the soot blower according to Fig. And 2 is dependent on the degree and distribution of the pollution of the heat exchanger surface and 2 by the synthesis gas.
  • compressed gas is blown onto the surfaces of the two prisms via the sootblast pipes 4 and 14 and the nozzles 5 and 15, and these are cleaned in the process.
  • the control valves 8 can be operated both manually and automatically. It has been shown that in most cases it is sufficient to alternately blow compressed gas onto the surfaces for short time intervals; In the period between the blowing intervals, only a small amount of compressed gas is led into the blowpipes in order to achieve a certain cooling effect and to avoid a possible blockage of the nozzles.
  • sootblower tube 4 Due to the smooth surface of the sootblower tube 4 'on one side, it is possible to use the same nozzles 5 over the entire length of the tube. It is also possible to have the diameter of the blowpipes continuously reduced so that the whole pipe forms an oblique cone.
  • the nozzle 5 according to FIG. 6 has the advantage that a large number of them are undrilled on the soot blowing tube 4 or 4 'during assembly, i.e. can still be attached without outlet bore 50 and only after commissioning - when the actual cleaning needs have been determined - only the really necessary nozzles 5 can be made ready for operation by simply producing the bore 50.
  • a nozzle 5 'with a larger diameter is provided, which forms a more acute angle with the plane in which the webs 7 extend than the nozzle 5 in FIGS. 3 and 4 .
  • the nozzle 5 ' is connected to the soot blowing tube 4' via a curved connecting tube 13.
  • control valve 8 For the sake of simplicity, only one control valve 8 is shown in each of FIGS. I and 2, although such a valve is provided for each soot blowing tube 4, 14. However, it may be more appropriate to use the compressed gas to control ge for all soot pipes 4 and all soot pipes 14 simultaneously by means of a single valve. Operational reliability can be increased if several control valves are connected redundantly in series and / or in parallel. It is also possible to use very simple shut-off valves instead of the control valves if the contamination is very high, so that the largest possible amount of soot blowing medium is constantly blown against the heat exchanger surfaces during normal operation.
  • the nozzles 5 and 15 can be directed onto walls other than those shown in FIGS. I and 2. In contrast to FIG. 2, if necessary, several nozzles can act simultaneously on the same area of a wall from different directions.
  • the sootblast tubes and the protective tubes can also have a cross-section other than circular, e.g. elliptical cross section.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Incineration Of Waste (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Description

Die Erfindung betrifft einen Russbläser für eine Wärmeübertragerfläche, die aus parallelen, miteinander zu einer Wand verschweissten, ein Kühlmedium führenden Rohren besteht, wobei in der Wand mindestens ein mit einem Russblasemedium beschickbares Russblaserohr vorgesehen ist, das mindestens eine Düse für den Austritt des Russblasemedium aufweist.The invention relates to a soot blower for a heat exchanger surface, which consists of parallel tubes which carry a cooling medium and are welded together to form a wall.

Ein solcher Russbläser ist aus der CH-PS 648 397 bekannt. Bei diesem Russbläser ist das Russblaserohr mit Abstand von einem Rohr der Wärmeübertragerfläche koaxial umgeben, so dass Kühlmedium im Raum zwischen den beiden Rohren strömt und das Russblaserohr gegen zu hohe Temperaturen schützt. Diese an sich gute Lösung weist jedoch den Nachteil auf, dass die Austrittstemperatur des Kühlmediums aus dem Doppelrohr von der Temperatur des Russblasemediums beeinflusst wird und daher von der Austrittstemperatur des aus den übrigen Rohren der Wärmeübertragerfläche austretenden Kühlmediums abweicht.Such a sootblower is known from CH-PS 648 397. In this sootblower, the sootblower tube is coaxially surrounded by a tube of the heat exchanger surface so that cooling medium flows in the space between the two tubes and protects the sootblower tube against excessive temperatures. However, this solution, which is good in itself, has the disadvantage that the outlet temperature of the cooling medium from the double tube is influenced by the temperature of the soot blowing medium and therefore deviates from the outlet temperature of the cooling medium emerging from the other tubes of the heat exchanger surface.

Unter Umständen ist ein relativ grosser Aufwand nötig, um einen Temperaturausgleich herbeizuführen.Under certain circumstances, a relatively large amount of effort is required to bring about temperature compensation.

Es ist Aufgabe der Erfindung, den Russbläser der eingangs beschriebenen Gattung so zu verbessern, dass er bei gleich gutem Schutz des Russblaserohres gegen hohe Temperaturen einen geringeren oder überhaupt keinen Einfluss auf die Austrittstemperatur des Kühlmediums der Wärmeübertragerfläche ausübt.It is an object of the invention to improve the soot blower of the type described in the introduction in such a way that, with the same protection of the sootblower tube against high temperatures, it exerts little or no influence on the outlet temperature of the cooling medium of the heat transfer surface.

Diese Aufgabe wird erfindungsgemäss dadurch gelöst, dass auf der dem Wärmeeinfall ausgesetzten Seite der Wand vor dem Russblaserohr und parallel zu diesem mindestens ein mit der Wärmeübertragerfläche verbundenes Schutzrohr angeordnet ist, das von gleichem Kühlmedium wie die Wärmeübertragerfläche durchströmt ist, und dass die Düse sich zwischen dem Schutzrohr und der Wand erstreckt. Das vor dem Russblaserohr angeordnete Schutzrohr ist praktisch den gleichen thermodynamischen Bedingungen wie die übrigen Rohre der Wärmeübertragerfläche ausgesetzt, so dass die Austrittstemperatur des Kühlmediums aus dem Schutzrohr und die aus den übrigen Rohren der Wärmeübertragerfläche im wesentlichen gleich sind. Darüberhinaus weist der Russbläser eine gute Zugänglichkeit des Russblaserohres bei der Montage und bei etwaigen Reparaturen auf, wobei - je nach Bedarf - eine Aenderung der Düsen oder ihrer Anzahl auf einfache Weise möglich ist.According to the invention, this object is achieved in that at least one protective tube connected to the heat exchanger surface is arranged on the side of the wall exposed to the heat and in front of the sootblower tube, through which the same cooling medium flows as the heat exchanger surface, and that the nozzle is located between the Protective tube and the wall extends. The protective tube arranged in front of the sootblast tube is exposed to practically the same thermodynamic conditions as the other tubes of the heat exchanger surface, so that the outlet temperature of the cooling medium from the protective tube and that from the other tubes of the heat exchanger surface are essentially the same. In addition, the sootblower has good accessibility to the sootblower tube during assembly and for any repairs, and - depending on the need - the nozzles or their number can be changed in a simple manner.

Einige Ausführungsbeispiele der Erfindung werden in der folgenden Beschreibung anhand der Zeichnung näher erläutert. Es zeigen:

  • Fig. I einen Querschnitt durch einen Synthesegaskühler, der einen Russbläser nach der Erfindung aufweist,
  • Fig. 2 einen Schnitt gemäss der Linie 11-11 in Fig. I,
  • Fig. 3 einen Ausschnitt einer Wärmeübertragerfläche nach Fig. I, jedoch mit einer anderen Ausführungsform des Russblaserohres,
  • Fig. 4 einen gleichen Ausschnitt wie in Fig. 3, jedoch an einer tiefer gelegenen Stelle der Wärmeübertragerfläche,
  • Fig. 5 einen Längsschnitt durch einen Teil des Russblaserohres in Fig. 3 und 4,
  • Fig. 6 einen Längsschnitt durch eine Düse eines Russblaserohres und
  • Fig. 7 einen Ausschnitt einer Wärmeübertragerfläche mit einer abgewandelten Düsenanordnung.
Some embodiments of the invention are explained in more detail in the following description with reference to the drawing. Show it:
  • I shows a cross section through a synthesis gas cooler having a soot blower according to the invention,
  • 2 shows a section along the line 11-11 in Fig. I,
  • 3 shows a section of a heat exchanger surface according to FIG. I, but with another embodiment of the sootblower tube,
  • 4 shows a section of the same as in FIG. 3, but at a lower point of the heat exchanger surface,
  • 5 shows a longitudinal section through part of the sootblower tube in FIGS. 3 and 4,
  • Fig. 6 shows a longitudinal section through a nozzle of a sootblower tube and
  • Fig. 7 shows a detail of a heat exchanger surface with a modified nozzle arrangement.

Gemäss Fig. und 2 bilden in einem Synthesegaskühler mehrere vertikale gerade, miteinander über Stege 7 gasdicht verschweisste, wasserführende Wandrohre 3 eine erste vertikale Wärmeübertragerfläche I, die die Form eines achtseitigen, regulären Prismas aufweist. Eine zweite Wärmeübertragerfläche 2, die ebenfalls die Form eines achtseitigen regulären Prismas 2 aufweist, besteht aus mehreren vertikalen, miteinander verschweissten Wandrohren 3' und Stegen 7'. Sie umgibt das Prisma der Wärmeübertragungsfläche I koaxial und ist um 22,5° gegegenüber dem inneren Prisma verdreht angeordnet. An ihren in Fig. 2 unteren Enden münden die Wandrohre 3 in einen achteckigen horizontalen Verteiler 31 und an ihren oberen Enden in einen dem Verteiler 31 gleichen und zu diesem parallel angeordneten Sammler 31'. Entsprechend münden die Wandrohre 3' unten in einem Verteiler 32 und oben in einem Sammler 32', wobei der Verteiler 32 und der Sammler 32' ebenfalls achteckig und einander gleich ausgebildet und zueinander parallel angeordnet sind. Die Sammler 31', 32' liegen auf gleicher Höhe, wogegen der äussere Verteiler 32 tiefer als der innere Verteiler 31 angeordnet ist. Die Wärmeübertragerflächen und 2 sind mit dem zugehörigen Verteiler 31 bzw. 32 und dem zugehörigen Sammler 31' bzw. 32' dicht verschweisst. Die Verteiler 31, 32 sind an mindestens einer nicht gezeigten Wasserquelle und die Sammler 31', 32' an mindestens einem nicht gezeigten Dampfverbraucher angeschlossen. Heisses Synthesegas, das in Richtung des Pfeiles 20 von oben nach unten durch das innere Prisma strömt, umströmt danach dessen Verteiler 31 (Pfeile 20') und steigt dann zwischen dem inneren Prisma und dem äusseren Prisma. Dabei gibt das Synthesegas Wärme an das Wasser in den Wandrohren 3 und 3' ab, wobei Dampf erzeugt wird. Die Wärmeübertragerflächen I und 2 sind mit ihren Verteilern 31 bzw. 32 und Sammler 31' bzw. 32' in einem gemeinsamen Druckbehälter 10 untergebracht, in dem weitgehend gleicher Druck herrscht.2 and 2 form in a synthesis gas cooler a plurality of straight vertical water-conducting wall tubes 3 welded to one another in a gas-tight manner via webs 7, a first vertical heat exchanger surface I which has the shape of an octagonal regular prism. A second heat exchanger surface 2, which also has the shape of an eight-sided regular prism 2, consists of a plurality of vertical wall tubes 3 ′ and webs 7 ′ welded to one another. It surrounds the prism of the heat transfer surface I coaxially and is rotated by 22.5 ° with respect to the inner prism. At their lower ends in FIG. 2, the wall pipes 3 open into an octagonal horizontal distributor 31 and at their upper ends into a collector 31 'which is the same as the distributor 31 and is arranged parallel to the latter. Correspondingly, the wall pipes 3 'open at the bottom in a distributor 32 and at the top in a collector 32', the distributor 32 and the collector 32 'likewise being octagonal and identical to one another and arranged parallel to one another. The collectors 31 ', 32' are at the same height, whereas the outer distributor 32 is arranged lower than the inner distributor 31. The heat exchanger surfaces 2 and 2 are tightly welded to the associated distributor 31 or 32 and the associated collector 31 'or 32'. The distributors 31, 32 are connected to at least one water source, not shown, and the collectors 31 ', 32' to at least one steam consumer, not shown. Hot synthesis gas, which flows in the direction of arrow 20 from top to bottom through the inner prism, then flows around its distributor 31 (arrows 20 ') and then rises between the inner prism and the outer prism. The synthesis gas gives off heat to the water in the wall pipes 3 and 3 ', steam being generated. The heat exchanger surfaces I and 2 are accommodated with their distributors 31 and 32 and collectors 31 'and 32' in a common pressure vessel 10, in which the pressure is largely the same.

In der Mitte jeder Seite des inneren Prismas ist ein Russblaserohr 4 vorgesehen, das mit Hilfe eines Steuerventils 8 mit einem als Russblasemedium wirkenden Druckgas aus mindestens einer nicht gezeigten Druckgasquelle beschickbar ist. Innerhalb des inneren Prismas ist vor jedem Russblaserohr 4 und parallel zu diesem ein Schutzrohr 6 angeordnet, das unten in den Verteiler 31 und oben in den Sammler 31' mündet. Die Schutzrohre haben den gleichen Durchmesser wie die Wandrohre 3 und bestehen aus dem gleichen Werkstoff wie diese. Sie schützen die Russblaserohre 4 vor zu hohen Temperaturen und sind ähnlichen thermodynamischen Bedingungen wie die Wandrohre 3 unterworfen, so dass der Dampfgehalt des aus ihnen austretenden Wasser-Dampf-Gemisches etwa gleich demjenigen des aus den Wandrohren 3 austretenden Gemisches ist. Mehrere Blechstücke 16 verbinden jedes Schutzrohr 6 mit den beiden nächstliegenden Wandrohren 3. Entlang den Russblaserohren 4 verteilt, sind Düsen 5 vorgesehen, die sich zwischen dem Schutzrohr 6 und den Wandrohren 3 erstrecken, und zwar durch die Lücken zwischen zwei Blechstücken 16. Die Düsen eines Blaserohres 4 sind abwechselnd gegen die jeweils übernächste Seite des inneren Prismas gerichtet, so dass die Innenfläche einer jeden Seite dieses Prismas von zwei Seiten her von Druckgas bestrichen wird (Fig. 2).In the middle of each side of the inner prism, a sootblower tube 4 is provided, which can be fed with the aid of a control valve 8 with a compressed gas acting as a sootblowing medium from at least one compressed gas source, not shown. Within the inner prism, a protective tube 6 is arranged in front of each sootblower tube 4 and parallel to it, which ends at the bottom in the distributor 31 and at the top in the collector 31 '. The protective tubes have the same diameter as the wall tubes 3 and are made of the same material as this. They protect the sootblast pipes 4 from excessive temperatures and are subject to similar thermodynamic conditions as the wall pipes 3, so that the steam content of the water-steam mixture emerging from them is approximately equal to that of the mixture emerging from the wall pipes 3. A plurality of sheet metal pieces 16 connect each protective tube 6 to the two nearest wall tubes 3. Distributed along the sootblower tubes 4, nozzles 5 are provided which extend between the protective tube 6 and the wall tubes 3, namely through the gaps between two sheet metal pieces 16. The nozzles one Blower tube 4 are directed alternately against the next but one side of the inner prism, so that the inner surface of each side of this prism is swept from two sides by compressed gas (FIG. 2).

Bei dieser Ausführungsform sind samtliche Rohre von jeweils mindestens einer Wandseite her zugänglich, was sowohl für die Montage wie auch für Reparaturen günstig ist.In this embodiment, all pipes are accessible from at least one wall side, which is favorable both for assembly and for repairs.

In jeder Achteck-Seite der äusseren Wärmeübertragerfläche 2 sind vier Russblaserohre 14 vorgesehen, die jeweils die Stelle eines Steges 7' einnehmen. Zwei der Blasrohre 14 sind im mittleren Bereich der Seite vorgesehen, und die Düsen 15 des jeweils links der Mitte liegenden Blaserohres 14 sind gegen die rechts von der Mitte vorgesehene Aussenseite des inneren Prismas gerichtet; entsprechend sind die Düsen 15 der jeweils rechts der Mitte befindlichen Blaserohre 14 gegen die links von der Mitte sich erstreckende Aussenseite des inneren Prismas gerichtet. Die beiden übrigen Russblaserohre 14 jeder äusseren Prismenseite sind nahe den Kanten dieses Prismas angebracht. Ihre Düsen 15 sind jeweils auf die der zugehörigen Kante benachbarte Seite des äusseren Prismas gerichtet. Auf diese Weise wird die äussere Oberfläche jeder Seite des inneren Prismas und die innere Oberfläche jeder Seite des äusseren Prismas aus zwei Richtungen mit Druckgas bestrichen. Das zwischen den beiden Prismen aufwärtsströmende Synthesegas wurde beim Abwärtsströmen im inneren Prisma bereits soweit abgekühlt, dass die Russblaserohre 14 des äusseren Prismas nicht gegen zu hohe Temperaturen geschützt werden müssen und sich ein Anordnen von Schutzrohren vor ihnen erübrigt.Four sootblast tubes 14 are provided in each octagon side of the outer heat exchanger surface 2, each taking the place of a web 7 '. Two of the blowpipes 14 are provided in the central region of the side, and the nozzles 15 of the blowpipe 14 located on the left of the center are directed towards the outside of the inner prism provided on the right of the center; Accordingly, the nozzles 15 of the blowpipes 14 located on the right of the center are directed towards the outside of the inner prism, which extends to the left of the center. The two remaining sootblast tubes 14 on each outer prism side are attached near the edges of this prism. Their nozzles 15 are each directed towards the side of the outer prism adjacent to the associated edge. In this way, the outer surface of each side of the inner prism and the inner surface of each side of the outer prism are coated with pressurized gas from two directions. The synthesis gas flowing upwards between the two prisms was already cooled down so far in the downward flow in the inner prism that the sootblast tubes 14 of the outer prism do not have to be protected against excessive temperatures and there is no need to arrange protective tubes in front of them.

Die Funktion des Russbläsers nach Fig. und 2 ist vom Grad und von der Verteilung der Verschmutzung der Wärmeübertragerfläche und 2 durch das Synthesegas abhängig. Durch Oeffnen der Steuerventile 8 wird Druckgas über die Russblaserohre 4 und 14 sowie die Düsen 5 und 15 auf die Oberflächen der beiden Prismen geblasen und diese dabei gereinigt. Die Steuerventile 8 können sowohl von Hand wie auch automatisch betätigt werden. Es hat sich gezeigt, dass es in den meisten Fällen genügt, Druckgas abwechselnd für jeweils kurze Zeitintervalle auf die Oberflächen zu blasen; in der Zeit zwischen den Blasintervallen wird eine nur kleine Menge Druckgas in die Blaserohre geleitet, um eine gewisse Kühlwirkung zu erreichen und eine eventuelle Verstopfung der Düsen zu vermeiden. Es ist in der Praxis schwierig, im voraus die Verteilung der Schmutzablagerung auf den Wärmeübertragerflächen zu bestimmen, da diese Verteilung von verschiedenen Parametern abhängt, wie beispielsweise Temperaturverteilung und Strömungsbild des Synthesegases. Wegen der erfindungsgemäss erreichten Zugänglichkeit ist es nun auf einfache und kostengünstige Weise möglich, nach Inbetriebnahme des Russbläsers die Anzahl, die Verteilung, die Richtung und die Art der Düsen 5 und 15 zu ändern, um eventuell nachträglich festgestellten Reinigungsbedürfnissen zu entsprechen. Es ist sogar möglich, erst nach dem an Ort und Stelle beobachteten Grad und der Verteilung der Verschmutzung die Düsen 5 und 15 einzubauen.The function of the soot blower according to Fig. And 2 is dependent on the degree and distribution of the pollution of the heat exchanger surface and 2 by the synthesis gas. By opening the control valves 8, compressed gas is blown onto the surfaces of the two prisms via the sootblast pipes 4 and 14 and the nozzles 5 and 15, and these are cleaned in the process. The control valves 8 can be operated both manually and automatically. It has been shown that in most cases it is sufficient to alternately blow compressed gas onto the surfaces for short time intervals; In the period between the blowing intervals, only a small amount of compressed gas is led into the blowpipes in order to achieve a certain cooling effect and to avoid a possible blockage of the nozzles. In practice, it is difficult to determine in advance the distribution of dirt deposits on the heat exchanger surfaces, since this distribution depends on various parameters, such as temperature distribution and flow pattern of the synthesis gas. Because of the accessibility achieved according to the invention, it is now possible in a simple and cost-effective manner to change the number, distribution, direction and type of nozzles 5 and 15 after the soot blower has been started up, in order to meet any cleaning needs which may have been determined subsequently. It is even possible to install the nozzles 5 and 15 only after the degree observed on the spot and the distribution of the contamination.

Gemäss Fig. 3, 4 und 5 weist ein Russblaserohr 4' in Strömungsrichtung des Druckgases abnehmenden Durchmesser auf, wobei zylindrische mit schiefkegeligen Abschnitten abwechseln, so dass sich auf der dem Schutzrohr zugewendeten Seite des Blaserohres 4' eine von oben bis unten glatt durchlaufende Mantelfläche ergibt. Das Russblaserohr 4' wird anstelle eines Steges zwischen zwei Wandrohre 3 dicht eingeschweisst. Die Durchmesserabnahme hat folgende Gründe:

  • - Jede Düse 5 bedingt eine Abnahme der Druckgasmenge innerhalb des Russblaserohres 4' und damit einen bestimmten Druckabfall. Mit zunehmender Anzahl von Düsen 5 summieren sich die Druckabfälle relativ rasch. Durch das Verringern des Querschnittes des Russblaserohres 4' wird der Druckverlust kompensiert, wobei die Abstufung so optimiert wird, dass die Kosten und der Druckverlauf innerhalb vernünftiger Grenzen bleiben.
  • - Beim Abkühlen des Synthesegases werden die Kondensations- und Solidifikationstemperaturen der in ihm enthaltenden Verschmutzungsprodukte unterschritten, so dass von diesem Punkt an die Verschmutzung der Wärmeübertragerfläche merklich grösser wird. Es ist daher zweckmässig, im unteren Bereich des inneren Prismas eine grössere Anzahl Düsen 5 vorzusehen als im oberen Bereich, so dass der Druckgasbedarf von oben nach unten zunimmt.
3, 4 and 5, a sootblower tube 4 'has a decreasing diameter in the flow direction of the compressed gas, cylindrical alternating with obliquely tapered sections, so that on the side of the blower tube 4' facing the protective tube there is a circumferential surface which runs smoothly from top to bottom . The sootblower pipe 4 'is welded tightly instead of a web between two wall pipes 3. The decrease in diameter has the following reasons:
  • - Each nozzle 5 causes a decrease in the amount of compressed gas within the sootblower tube 4 'and thus a certain pressure drop. With an increasing number of nozzles 5, the pressure drops add up relatively quickly. By reducing the cross section of the sootblower tube 4 ', the pressure loss is compensated, the gradation being optimized in such a way that the costs and the pressure curve remain within reasonable limits.
  • - When the synthesis gas cools down, the condensation and solidification temperatures of the pollution products contained in it fall below, so that from this point the pollution of the heat exchanger surface becomes noticeably greater. It is therefore expedient to provide a larger number of nozzles 5 in the lower area of the inner prism than in the upper area, so that the pressure gas requirement increases from top to bottom.

Durch die auf einer Seite glatte Mantelfläche des Russblaserohres 4' ist es möglich, über die ganze Länge des Rohres gleiche Düsen 5 zu verwenden. Es ist auch möglich, die Blaserohre im Durchmesser kontinuierlich abnehmen zu lassen, so dass das ganze Rohr einen schiefen Kegel bildet.Due to the smooth surface of the sootblower tube 4 'on one side, it is possible to use the same nozzles 5 over the entire length of the tube. It is also possible to have the diameter of the blowpipes continuously reduced so that the whole pipe forms an oblique cone.

Die Düse 5 nach Fig. 6 hat den Vorteil, dass bei der Montage eine grosse Anzahl von ihnen am Russblaserohr 4 bzw. 4' ungebohrt, d.h. noch ohne Austrittsbohrung 50, befestigt werden kann und erst nach der Inbetriebnahme - wenn die tatsächlichen Reinigungsbedürfnisse festgestellt worden sind - nur die wirklich notwendigen Düsen 5 durch einfaches Herstellen der Bohrung 50 betriebsbereit gemacht werden.The nozzle 5 according to FIG. 6 has the advantage that a large number of them are undrilled on the soot blowing tube 4 or 4 'during assembly, i.e. can still be attached without outlet bore 50 and only after commissioning - when the actual cleaning needs have been determined - only the really necessary nozzles 5 can be made ready for operation by simply producing the bore 50.

Gemäss Fig. 7 ist - abweichend von den bisher beschriebenen Düsen 5 - eine Düse 5' mit grösserem Durchmesser vorgesehen, die mit der Ebene, in der sich die Stege 7 erstrecken, einen spitzeren Winkel als die Düse 5 in Fig. 3 und 4 bildet. Die Düse 5' ist über ein gekrümmtes Verbindungsrohr 13 am Russblaserohr 4' angeschlossen.7, in contrast to the previously described nozzles 5, a nozzle 5 'with a larger diameter is provided, which forms a more acute angle with the plane in which the webs 7 extend than the nozzle 5 in FIGS. 3 and 4 . The nozzle 5 'is connected to the soot blowing tube 4' via a curved connecting tube 13.

Einfachheitshalber sind in Fig. I und 2 nur je ein Steuerventil 8 gezeigt, obwohl für jedes Russblaserohr 4, 14 ein solches Ventil vorgesehen ist. Es kann jedoch zweckmässiger sein, die Druckgasmenge für alle Russblaserohre 4 und alle Russblaserohre 14 gleichzeitig mittels eines einzigen Ventils zu steuern. Die Betriebssicherheit kann gesteigert werden, wenn mehrere Steuerventile in Serie und/oder parallel geschaltet redundant vorgesehen werden. Es ist auch möglich, bei sehr hoher Verschmutzung anstelle der Steuerventile ganz einfache Absperrventile zu verwenden, so dass im Normalbetrieb die grösstmögliche Menge an Russblasemedium ständig gegen die Wärmeübertragerflächen geblasen wird.For the sake of simplicity, only one control valve 8 is shown in each of FIGS. I and 2, although such a valve is provided for each soot blowing tube 4, 14. However, it may be more appropriate to use the compressed gas to control ge for all soot pipes 4 and all soot pipes 14 simultaneously by means of a single valve. Operational reliability can be increased if several control valves are connected redundantly in series and / or in parallel. It is also possible to use very simple shut-off valves instead of the control valves if the contamination is very high, so that the largest possible amount of soot blowing medium is constantly blown against the heat exchanger surfaces during normal operation.

Je nach Anwendungsfall können die Düsen 5 und 15 auf andere Wände gerichtet werden, als in Fig. I und 2 gezeigt. Im Gegensatz zur Fig. 2 können bei Bedarf mehrere Düsen auf den gleichen Bereich einer Wand, aus verschiedenen Richtungen simultan einwirken.Depending on the application, the nozzles 5 and 15 can be directed onto walls other than those shown in FIGS. I and 2. In contrast to FIG. 2, if necessary, several nozzles can act simultaneously on the same area of a wall from different directions.

Die Russblaserohre und die Schutzrohre können auch einen anderen als kreisrunden Querschnitt aufweisen, z.B. elliptischen Querschnitt.The sootblast tubes and the protective tubes can also have a cross-section other than circular, e.g. elliptical cross section.

Claims (6)

1. A soot-blower for a heat-exchanger surface consisting of parallel tubes carrying a coolant and welded together to form a wall, at least one soot-blowing tube to which a soot-blowing medium can be fed being provided in the wall, said tube comprising at least one nozzle for the discharge of the soot-blowing medium, characterised in that at least one protective tube is disposed upstream of and parallel to the soot-blowing tube on that side of the wall which is exposed to the heat, said protective tube being connected to the heat-exchanger surface and carrying the same coolant as the latter, and in that the nozzle extends between the protective tube and the wall.
2. A soot-blower according to claim 1, characterised in that the wall of the heat-exchanger surface forms a vertical polygonal and preferably regular prism having a soot-blowing tube in the middle of each side, and in that the nozzles of each soot-blowing tube are so directed towards the interior of the prism that the jets of soot-blowing medium each sweep one side of the prism adjacent the associated side.
3. A soot-blower according to claim 1 or 2, characterised in that the protective tube and the heat-exchanger surface tubes are connected to common headers.
4. A soot-blower according to any one of claims 1 to 3, characterised in that the soot-blowing tube has a diameter which decreases continuously or stepwise in the direction of flown of the soot-blowing medium.
5. A soot-blower according to claim 4, in which the diameter decreases stepwise, characterised in that the diameter decrease is such that a rectilinear outer surface forms on that side of the soot-blowing tube which faces the heat.
6. A soot-blower according to any one of claims 1 to 5, characterised in that throttling means are provided to control the flow of soot-blowing medium through the soot-blowing tube.
EP86110284A 1985-09-03 1986-07-25 Soot blower Expired - Lifetime EP0213380B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH3779/85 1985-09-03
CH3779/85A CH667521A5 (en) 1985-09-03 1985-09-03 SUSSBLAESER.

Publications (3)

Publication Number Publication Date
EP0213380A2 EP0213380A2 (en) 1987-03-11
EP0213380A3 EP0213380A3 (en) 1988-09-21
EP0213380B1 true EP0213380B1 (en) 1990-03-21

Family

ID=4263305

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86110284A Expired - Lifetime EP0213380B1 (en) 1985-09-03 1986-07-25 Soot blower

Country Status (7)

Country Link
US (1) US4765394A (en)
EP (1) EP0213380B1 (en)
JP (1) JPH0776603B2 (en)
CN (1) CN1008660B (en)
CH (1) CH667521A5 (en)
DE (1) DE3669772D1 (en)
ZA (1) ZA864669B (en)

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19533908C2 (en) * 1995-09-13 1998-07-23 Gutehoffnungshuette Man Waste heat boiler
DE19649532A1 (en) * 1996-11-29 1998-06-04 Gutehoffnungshuette Man Synthesis gas heat exchanger system
JP2005172417A (en) * 2003-11-20 2005-06-30 United Technol Corp <Utc> Gas guiding device and operation method of internal face cleaning apparatus
US20050125932A1 (en) * 2003-12-11 2005-06-16 Kendrick Donald W. Detonative cleaning apparatus nozzle
US20050126595A1 (en) * 2003-12-11 2005-06-16 Flatness Scott A. Detonative cleaning apparatus
US7047908B2 (en) * 2003-12-11 2006-05-23 United Technologies Corporation Cooling flange
US8684070B2 (en) * 2006-08-15 2014-04-01 Babcock & Wilcox Power Generation Group, Inc. Compact radial platen arrangement for radiant syngas cooler
US8381690B2 (en) * 2007-12-17 2013-02-26 International Paper Company Controlling cooling flow in a sootblower based on lance tube temperature
MX2010012794A (en) * 2008-05-27 2010-12-14 Georgia Pacific Consumer Prod Ultra premium bath tissue.
EP2321388B1 (en) * 2008-09-01 2015-09-30 Shell Internationale Research Maatschappij B.V. Self cleaning arrangement
DE102011110926A1 (en) * 2011-07-20 2013-01-24 Clyde Bergemann Gmbh Maschinen- Und Apparatebau Cleaning device for a convection section of a thermal power plant
US9494371B2 (en) 2011-12-28 2016-11-15 Liebert Corporation Pumped refrigerant cooling system with 1+1 to N+1 and built-in redundancy
US9706685B2 (en) 2011-12-28 2017-07-11 Liebert Corporation Cooling system for high density heat loads
WO2014117357A1 (en) * 2013-01-31 2014-08-07 Tenneco Automotive Operating Company Inc. Multi-lobed soot blower
CN105865228B (en) * 2016-04-06 2018-01-16 西安交通大学 It is a kind of for flue gas waste heat recovery from cleaning heat exchanger and using the heat exchanger from ash removal method

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1939387A (en) * 1933-12-12 Cooling means for soot blower
US1517440A (en) * 1921-10-18 1924-12-02 Frederick W Linaker Air-cooled soot cleaner
GB208485A (en) * 1922-07-12 1923-12-12 Diamond Power Speciality Improvements in boiler cleaners
US1664865A (en) * 1923-01-15 1928-04-03 Diamond Power Speciality Boiler cleaner
US1840544A (en) * 1923-07-02 1932-01-12 Diamond Power Speciality Boiler cleaner
DE444435C (en) * 1925-05-31 1927-05-17 Jacques Piedboeuf G M B H Soot blow-off device for water tube boiler
GB288830A (en) * 1927-04-30 1928-04-19 Wilfred Rothery Wood Improvements relating to water tubes for use in boilers or furnaces
DE744500C (en) * 1941-04-04 1944-01-18 Herpen Co Kg La Mont Kessel Russblaeser
ES357569A1 (en) * 1967-09-06 1970-03-16 Rheinstahl Henschel Ag Improvements in or relating to steam generators having soot blower devices.
CH648397A5 (en) * 1980-09-19 1985-03-15 Sulzer Ag SUSSBLAESER.
DE3312599A1 (en) * 1983-04-08 1984-10-11 Krupp-Koppers Gmbh, 4300 Essen SUSSBLASER FOR ELIMINATING DEPOSITS IN GAS-FLOWED ROOMS, LIKE HEAT EXCHANGERS, REACTION ROOMS AND THE LIKE
DE3406893C3 (en) * 1984-02-25 1996-02-08 Babcock Energie Umwelt Convection cooler

Also Published As

Publication number Publication date
JPH0776603B2 (en) 1995-08-16
CH667521A5 (en) 1988-10-14
DE3669772D1 (en) 1990-04-26
JPS6256794A (en) 1987-03-12
ZA864669B (en) 1987-02-25
US4765394A (en) 1988-08-23
CN86105365A (en) 1987-03-04
CN1008660B (en) 1990-07-04
EP0213380A2 (en) 1987-03-11
EP0213380A3 (en) 1988-09-21

Similar Documents

Publication Publication Date Title
EP0213380B1 (en) Soot blower
EP0716268A2 (en) Cooled wall part
CH653360A5 (en) HEISSGASKUEHLER AT A coal gasification plant.
DE2323986A1 (en) FLAME TUBE BOILERS FOR GAS AND LIQUID FUELS
DE1426648C3 (en) Rapid steam generator
DE3206625C2 (en) Retractable sootblower
CH670501A5 (en)
EP0377089B1 (en) Heat exchanger, especially for cooling a cracking gas
DE2459472C2 (en) GAS HEATED STEAM GENERATOR, IN PARTICULAR FOR NUCLEAR REACTOR PLANTS
DE4232880A1 (en) Fossil-fuelled steam-generator - has tubes forming flue walls joined together gas-tight at bottom and leaving intervening gaps further up
EP1923652B1 (en) Tube bundle heat exchanger with a pipe support with integrated cleaning device
DE3538515C2 (en)
EP0171558B1 (en) Heat-exchange apparatus
EP3134676B1 (en) Heat exchanger
DE4244303A1 (en) Impact cooling system for cooling surface e.g. of combustion chamber wall
CH648397A5 (en) SUSSBLAESER.
CH662638A5 (en) HEAT TRANSFER SYSTEM, PREFERRED FOR A PROCESS GAS.
DE3317490C2 (en) Heat exchanger
EP0473946B1 (en) Sectional boiler
DE3908277C2 (en) Protection against erosion for heat exchangers
AT228446B (en) Induction apparatus, in particular for high pressure ventilation systems
DE19515291C2 (en) Device for cleaning heat exchangers
EP0394758A2 (en) Heat exchanger
EP0085131B1 (en) Heat-transfer apparatus for cooling gases contaminated with particles
DE351385C (en) Boiler body made up of two or more adjacent chambers

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): BE DE FR GB IT NL

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): BE DE FR GB IT NL

17P Request for examination filed

Effective date: 19890308

17Q First examination report despatched

Effective date: 19890712

ITF It: translation for a ep patent filed

Owner name: ING. ZINI MARANESI & C. S.R.L.

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): BE DE FR GB IT NL

REF Corresponds to:

Ref document number: 3669772

Country of ref document: DE

Date of ref document: 19900426

ET Fr: translation filed
GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
ITTA It: last paid annual fee
ITPR It: changes in ownership of a european patent

Owner name: TRASFORMAZIONE SOCIETARIA;SULZER AKTIENGESELLSCHAF

NLT1 Nl: modifications of names registered in virtue of documents presented to the patent office pursuant to art. 16 a, paragraph 1

Owner name: SULZER AG TE WINTERTHUR, ZWITSERLAND.

NLS Nl: assignments of ep-patents

Owner name: ABB MANAGEMENT AG TE BADEN, ZWITSERLAND.

REG Reference to a national code

Ref country code: FR

Ref legal event code: TP

Ref country code: FR

Ref legal event code: CD

BECH Be: change of holder

Free format text: 940420 *ABB MANAGEMENT LTD

REG Reference to a national code

Ref country code: GB

Ref legal event code: 732E

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19960613

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19960617

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 19960620

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19960621

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19960627

Year of fee payment: 11

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19970725

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19970731

BERE Be: lapsed

Owner name: ABB MANAGEMENT LTD

Effective date: 19970731

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19980201

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19970725

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19980331

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

Effective date: 19980201

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19980401

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20050725