BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to an erosion resistant wall assembly according to claim l. The present invention thereby relates to a wall assembly in which a wall has been provided with a surface that is resistant to erosion caused by particulate material and high temperature of the surroundings. Such wall assembly typically comprises a substantially gas-tight wall support, a wall lining, and an anchor means including an anchor, for connecting said wall lining to said wall support. The present invention also relates to a circulating fluidized bed reactor system including a metal roof structure with a refractory lining for the roof structure, as defined in independent claim 20.

Most erosion in industrial processes occurs where large volumes of abrasive particles such as coal, catalyst, sand, shale, limestone etc. change direction of flow via elbows, separators, swirl vanes and the like. Erosion often occurs e.g. as a result of low angle impingement by large volumes of the abrasive particles which move at varying velocities. Specifically in hot conditions, e.g. at temperatures of 800 ^β C and above, the abrasive affect of the particles is even more exhaustive. Also simple exposure to high temperature (even without the effect of impinging particles) may cause damage to the wall in a long run. Particularly fluidized bed reactor systems - and, due to their nature, especially circulating fluidized bed reactor systems - have very severe and demanding conditions inside the hot loop. Arch and/or roof constructions have been found to be particularly difficult to line reliably and cost effectively. These areas are also subject to vibration/movement due to the large volumes of bed material circulating through the hot loop system.

Several systems have been established to resist this type

of erosion. For example, monolithic, cement or phosphate bonded castable (and plastic) refractories held by steel anchors have been utilized to resist this type of erosion. Also, the above-mentioned refractories have been installed on V-anchors or S-bar anchors.

However, known systems have drawbacks, which affect their reliability, which adversely affect their reliability, for example their resistance to possible movements of the refractory lining has been found to be poor. Temperature excursions above the average operating temperature can reduce the strength of the steel anchors in the hotface lining, reducing the ability of the anchor to support the lining. Where existing ceramic anchors are utilized they do not have sufficient flexibility when movement occurs. This causes failures in the ceramic anchors by shearing of the anchor or failure of the support attachment.

It is the primary object of the present invention to provide a simple yet effective, erosion resistant wall assembly and circulating fluidized bed system including a wall with a refractory lining, which essentially avoids the drawbacks of the prior art.

It is more particularly an object of the present invention to provide an erosion resistant wall assembly with an anchor arrangement which reliably withholds the forces caused by refractory lining attached thereto.

It is still further an object of the present invention to provide an erosion resistant wall assembly with an anchor arrangement which provides a movable connection between the wall and the refractory lining.

The objects of the present invention are in accordance with the present invention solved by an erosion resistant wall assembly comprising the features of claim 1 and by a circulating fluidized bed system comprising the features of

independent claim 20.

According to one aspect of the present invention, an erosion resistant wall assembly is provided comprising the following elements: A substantially gas-tight wall support (typically of metal, such as fins of a water cooled roof of a cyclone separator associated with a fluidized bed reactor) . A wall lining (preferably having at least two layers, a first working lining most remote from the wall support and of a refractory material, and a second backup lining of heat insulating material between the wall support and the working lining) . An anchor means including a solid anchor (preferably a ceramic polygonal parallelepiped having grooved surfaces) substantially rigidly connected to the wall lining (typically rigidly connected to the working lining, not the backup lining) ; and connecting means for connecting the solid anchor to the wall support.

The connecting means typically comprise a bar having first and second ends and connected at the first end thereof to the wall support, the second end extending away from the wall support; a rod extending substantially perpendicularly to the bar and on both sides of the bar (preferably passing through an opening in the bar and/or reciprocal with respect to the bar) and a hanger means for connecting the solid anchor to the rod on both sides of the bar. The solid anchor may include a hanger support groove and the hanger means may comprise a pair of metal wire hangers that are welded to the rod. The rod typically has a length substantially equal to the width of the solid anchor, and the rod length and solid anchor are parallel. The metal wires may have turns around the rod at both ends thereof and a section between the turns engaging the hanger support groove, and the wire turns may be welded to the rod which(along with the bar) is preferably of metal. The connecting means may further include a clip welded to the wall support and in turn welded to the bar, the bar extending perpendicular to the wall support.

The wall assembly is typically part of a circulating fluidized bed reactor system and is disposed at a portion of the reactor system having an operating temperature of at least about 700 ^β C.

According to another aspect of the present invention, an anchoring assembly is provided comprising the following components: A ceramic solid anchor substantially in the form of a grooved surface polygonal parallelepiped, and including a hanger support groove. A bar for connecting the solid anchor to a wall. A rod extending substantially perpendicular to the bar and extending on opposite sides of the bar, having opposite ends on the opposite sides of the bar. And a hanger engaging the hanger support groove and both ends of the rod for supporting the solid anchor on the rod.

Typically the rod extends through an opening in the bar and is rotatable and reciprocal with respect to the bar. The hanger typically comprises at least one metal wire including turns wrapped around both ends of the rod and welded to the rod. A tack weld is preferably provided between the rod and bar, the tack weld being sufficiently weak to break upon movement of the anchor with respect to the bar, in the typical operating environment in which the anchoring assembly is utilized.

According to another aspect of the present invention, a circulating fluidized bed reactor system is provided. The reactor system comprises the following components: A combustion chamber including an upper section past which hot exhaust gases flow. A cyclone separator connected to the upper section of the combustion chamber and for receiving hot exhaust gases from the combustion chamber, the separator including a metal roof structure. A refractory lining for the roof structure. A ceramic solid anchor substantially rigidly connected to the refractory

lining. And, connecting means for connecting the solid anchor to the metal roof structure for relative movement therebetween without significant harm to the refractory lining.

The solid anchor may comprise a polygonal parallelepiped having a hanger support groove, and the connecting means may include a bar, rod and hanger support, such as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, exemplary embodiments of the invention are now described in more detail with reference to the enclosed drawings.

Fig. 1 is a schematic side view of a circulating fluidized bed reactor utilizing the present invention, Fig. 2 is a front view of the detail A in the Fig. 1, and

Fig. 3 is a side view of the detail A in the Fig. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to Fig. 1 of the drawings the reference numeral 10 refers in general to a conventional Circulating Fluidized Bed (CFB) reactor with steam generation tube walls 16. The CFB reactor 10 includes a solid separator cyclone 14 which receives gas/solid suspension resulting from the reactions taken place in the reaction chamber 12 of the CFB reactor 10. The CFB reactor 10 may be operated for combustion of fuel material as well known by the art, or used in any other manner and including any other configuration known in connection with CFB reactors.

In a CFB combustor, the temperature is high, typically between about 700 - 900°C, and a considerable volume of solids carried by the gases out of the reactor chamber 12,

resulting in the necessity of protecting the water walls in contact with gases of the CFB reactor 10. Fig. 1 shows a sectional detail A of the roof of the cyclone 14. The detail A is shown more specifically in Figs. 2 and 3.

In Fig. 2 there is shown an enlargement of the detail A of Fig. 1. FIG. 2 shows a wall support section 20, typically of metal (e.g. steel) , which forms a substantially gas- tight construction. Since typically, when the wall 21 of which support 20 is a part comprises a plurality of fluid circulating tubes connected to each other by fins or bars, the wall support 20 may be such a fin connecting two adjacent tubes of the cooled wall of the cyclone 14. The wall 21 also includes a wall lining 22 supported by the support 20. An anchoring means, generally referred to by numeral 24, sustains the lining 22 of the wall 21. The anchoring means 24 preferably has a solid anchor section 241, e.g. of ceramic material, substantially rigidly connected to the outer section 221 of the lining 22.

The outer section 221 is a wear resistant material, such as castable refractory, and is known as the "working lining". A predefined opening 25 is formed into the outer section 221 in which the solid anchor 241 fits. The opening 25 may be tightened by casting or gunning conventional hot face lining material or grout or cement around the anchor 241 after installation. The fit of the anchor 241 in working lining 221 is so tight that it will withstand vibration, dislocating and thermal forces or the like, without movement. The surface of the anchor 241 is grooved or deformed, as illustrated at 26 in FIG. 2, to increase the surface area and the anchoring ability.

The inner section 222 of the lining 22 is of insulating material, and is known as the "back-up lining". Each solid ceramic anchor 241 preferably is a ceramic power-press formed for maximum strength. The anchors 241 must be capable of carrying the load under suspension and provide

adequate refractoriness. The solid anchor 241 is substantially in a form of a polygonal (preferably rectangular) parallelepiped, having at least one groove 26 preferably in each face thereof. For example, as seen in FIG. 3, spiral grooves 26 may be provided.

The anchor 241 is connected to the wall supporting section 20 by a connecting means 242, mounted to the wall support section 20 and connecting the solid anchor section 241 to the support section 20. The connecting means 242 according to the invention preferably includes a clip 244 preferably welded to the wall 20, as indicated at 27, and a bar 246, the bar being connected to the wall support 20 and substantially perpendicular thereto. During installation the clip 244 is preferably temporarily attached to the bar 246 by a bolt 248, but preferably the clip 244 is eventually welded (249) to the bar 246 to ensure a reliable and rigid joint. A rod 250 is provided at lower section of the bar 246, passing through an opening 28 (see FIG. 3) in the bar. The rod 250 is preferably installed to extend substantially equal distance on both sides of the bar 246, and perpendicular to the bar 246.

The solid anchor section 241 is coupled to the rod 250 by a hanger means 252. The hanger means 252 preferably includes two or more pieces of wire-like hangers 30 adapted to connect the solid anchor 241 at the base support groove

31 to the rod 250 on opposite sides of the bar 246. The rod

250 is, according to the invention, assembled to the bar 246 so that at least rotating and/or transverse movement is allowed. According to a preferred manner of installation a light tack 254 is provided for installation of refractory lining 22. The tack 254 is sufficiently weak so that it breaks if movement of the lining 22 occurs. This way, both the installation and the operation of the lining is taken into account.

The rod 250 has a length substantially equal to the width

of the solid anchor 241, and they are parallel. The hanger preferably is formed of two pieces 30 of substantially similar metal wire including end sections 252' (see FIG.2) turning around the rod 250 at both ends of the rod 250, and a section 252' ' therebetween passing along a groove 31 in the solid anchor section 241. The end sections 252' of the wire hanger wires 30 turn around the rod 250 at both ends of the rod 250 and are rigidly connected to the rod 250, preferably, by welding (see welds 32) .

Preferably the elements 30, 250, 244 and 246 are of metal (such as steel) , and are compatible for welding to each other, or are attachable together by suitable adhesives. The back-up lining 222 may be deformed or cut away to accommodate the elements 246, 244, 250, 252, or an opening may be pre-formed in lining 222 to receive these elements.

Fig. 3 shows a side view of the anchoring system of Fig. 2. The clip 244 is illustrated as narrower than the bar 246, which is only to save material; it may be possible to provide both the clip 244 and the bar 246 of substantially equally-sized plates.

Significant modifications may be made without departing from the basic idea of the present invention. For example, the hanger 252 is shown to form a hook-like arrangement around the rod 250, the hanger wires 30 may be as illustrated at 252' ^• in FIG. 3, i.e. they may be wrapped around the rod 250 also from below the rod 250. Also the hanger means may include bars or other shapes besides wires, may be made of a wide variety of material, and even made integral with one of the rod 250 or anchor 241.

FIG. 3 shows that the bolt 248 (FIG.2) may be removed after the joint is secured by the weldment 249, only the hole 33 which received the bolt 248 remaining. Instead of conventional bolt 248, there may be a specifically constructed installation tool to support the anchor 241

prior to the welding.

While the present invention is disclosed in connection with a CFB reactor (e.g. of a fluid-cooled steam generating facility) , it may well be utilized also in other devices requiring robust, erosion resistant wall assemblies, such as waste heat boilers in e.g. metallurgical applications or municipal waste incineration plants. Also various pressurized combustion/gasification systems may utilize the invention.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.