Patent Application
20150233574
The present invention relates to a boiler wall protection block, an assembly of such block and a ferrule, and a boiler wall provided with such assembly.
Boilers are used in petrochemical applications, for instance in those for regaining sulphur from crude petroleum. Herein, gasses and fluids are burned to eliminate harmful substances, or to enable separation thereof. During this process, burning heat is regained by blowing the burning gasses through a boiler.
Since these gasses are usually corrosive and the temperatures are too high to submit the boiler walls thereto, and in particular the tube-panels covering those walls, a protection is required. For this purpose, multiple solutions are known in the art.
One solution is to apply a coating of downpoured or pulvered concrete against the tube panels, with through-holes for the tubes made by so-called ferrules.
Another solution is to apply ferrules with integrated blocks, that form part of a protection wall. The blocks may be designed in such way that they can be mounted in a wall-covering pattern. In the art, four and six-sided blocks are applied.
Yet another solution is to apply ferules provided with a flange at one outer edge, that cooperate with separate blocks, having a through hole in the middle, wherein the blocks may or may not be designed to cover an entire wall when applied in a pattern. This latter solution, with six-sided blocks, is for instance known from the U.S. Pat. No. 5,775,269 or the international patent application WO 2000/70265.
The existing solutions have certain disadvantages however. In particular, the blocks tend to get loose and as a result can cause the ferrule they surround to break, allowing hot corrosive gasses to attack the wall behind the adjacent blocks
The purpose of the present invention is to take away the disadvantages of the prior art, or at least to provide a useful alternative.
The present invention thereto proposes a boiler wall protection block, comprising an essentially parallellogram shaped body with an annular cut-out at all four corners, with the cutting point of two adjacent sides as a centre.
The configuration according to the invention has multiple advantages. The lozenge shaped body allows to cover walls with various surface forms, and thanks to its shape, it is held in place by more than one ferrule, which contributes to the overall robustness. In particular, the annular cut outs at the four corners enable one block to be held in place by multiple ferrules.
In an alternative embodiment, four of the above described blocks can be seen as one element, which means that the boiler tube protection block further comprises a central annular through hole for a ferrule and an annular cut-out at the middle of all four sides, with the centre coincident with the side; wherein the central annular through hole and the annular cut-outs at the middle of the four sides have the same radius as the annular cut-out at all four corners.
In a preferred embodiment, the boiler wall protection bloc comprises a first pair of adjacent flanges at an angle of 60 degrees, and a second pair of adjacent flanges at 120 degrees. This shape enables to cover a surface when laid in a pattern with identical blocks, without leaving intermediate holes or recesses.
In a further embodiment, the annular through hole and the annular cut outs have a rounded or tapered edge, for accepting a flange of a ferrule. The ferrule can thus be embedded in the block, which leads to a smoother and thus less fragile surface.
In yet a further embodiment, two adjacent sides have a protrusion, and the two other adjacent sides have a corresponding recess. When a boiler wall is furnished with blocks according to the present invention, adjacent blocks lock each other, more or less in a roofing-tile wise, while the assembly of blocks is kept in place by the ferrules, arranged in the annular holes of each separate blocks, and the annular holes formed by the annular cut outs of four adjacent blocks. Another advantage of this construction is that no direct radiation of heat can reach the boiler wall.
In a practical realisation, the protrusions and recesses may for instance extend over about half the thickness of the block. Such block can thus be imagined as a two-layer lozenge-shaped block, wherein the two layers are shifted over a distance in their length and width directions.
When arranging the boiler wall protection blocks according to the invention, a heat-resistant paper gasket may be applied between the ferrule and the annular through-hole, as well as between adjacent protection blocks, to assure a heat- and radiation tight connection. The ferrules to be used have a radius essentially corresponding to the central annular hole of the block, and for instance a six-sided or annular flange. This block may be manufactured from one or more compounds selected from the group consisting of Al2O3, ZrO2, SiO2, TiO2, Y2O3, Na2O, Nb2O5, La2O3, Fe2O3, CaO, SrO, CeO2, MgO, Cr2O3, CuO, the mixed oxides thereof, SiC, TiC, Si3N4 and AlN.
In order to further prevent heat radiation to the boiler wall, a double layer of blocks may be applied, wherein blocks of the two layers are mutually rotated 120 degrees. In this case, rounded or tapered edges may only be considered necessary for the blocks that receive the flanges of the ferrules, which may form an inner layer. The outer layer, i.e. the layer between the inner layer and the boiler wall, may be manufactured without.
The blocks according to the invention may be massive or at least partially hollow, and cavities may be provided to be filled with concrete, for mounting the blocks to the boiler wall with pre-mounted anchors
The invention will now be explained into more detail with reference to the following figures. Herein:
a, b show a combination of a block according to the invention and a ferrule;
a shows a composition of multiple blocks and ferrules according to the invention;
a and b show different perspectives of a combination of a block 11 according to the invention and a ferrule 21. As can be seen in
a shows a composition 30 of multiple blocks 31 and ferrules 32 according to the invention. In this example, the ferrules 32 have annular flanges instead of the six-sided ones as shown in
b shows the use of paper gaskets 36 between the blocks 31, for obtaining a gas-tight connection. The paper may for instance be 2 or 3 mm thick in an uncompressed state, and 1 mm in a compressed state.
Besides the examples shown, multiple variations are possible, all falling within the scope of the present application, as determined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009451 | Sep 2012 | NL | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/NL2013/050656 | 9/12/2013 | WO | 00 |
