Cassette integrated catalyst for flue gas cleaning

Abstract

Cassette integrated catalyst for flue gas cleaning comprises one or more depressions in the cassette wall or several of the walls to provide increased structural strength of the cassette and an improved fix of the catalyst monolith or monoliths comprised within the cassette.

Claims

1. A cassette integrated catalyst for flue gas cleaning, the catalyst comprises at least one monolith and said cassette comprises: a first open end, a second open end, and at least one wall adapted to fit around said at least one monolith, wherein the cassette further comprises at least one depression in the at least one wall to fix said at least one monolith in the cassette, the at least one wall has a bent side edge and a plurality of notches in the side opposite thereto, whereby the bent side edge and the side opposite thereto are capable of being welded together to form a corner via a lap joint and spot welds in the plurality of notches.

2. The cassette integrated catalyst according to claim 1, wherein said at least one depression projects inwards in the cassette.

3. The cassette integrated catalyst according to claim 1, wherein the at least one depression and the cross sectional area of the cassette is dimensioned relative to the cross sectional area of said at least one monolith to press-fit the at least one monolith in the cassette, thereby fixing the at least one monolith in the cassette.

4. The cassette integrated catalyst according to claim 1, wherein the at least one wall comprises a bent plate or plates which are compressed around said at least one monolith and fixed in a compressed position.

5. The cassette integrated catalyst according to claim 4, wherein the bent plate or plates comprise 90 bends.

6. The cassette integrated catalyst according to claim 1, wherein the at least one wall comprises one bent plate which is compressed around said at least one monolith and fixed in a compressed position.

7. The cassette integrated catalyst according to claim 4, wherein the bent plate or plates are fixed in the compressed position by means of welding or geometrical interlock of at least two edges of said plate or plates.

8. The cassette integrated catalyst according to claim 1, wherein said cassette has a rectangular, triangular, hexagonal, or circular cross section.

9. The cassette integrated catalyst according to claim 1, wherein said cassette comprises a plurality of depressions on at least one of said walls.

10. The cassette integrated catalyst according to claim 1, wherein said at least one depression is longitudinal, thereby providing additional stiffness to the at least one wall comprising said at least one depression.

11. The cassette integrated catalyst according to claim 1, wherein said cassette further comprises at least one collar or one or more inward projecting edges adjacent to at least one of the open ends of said cassette, thereby preventing axial movement of said at least one monolith in said cassette.

12. The cassette integrated catalyst according to claim 1, wherein said cassette is made from steel plate with a thickness of 0.2 mm-4 mm.

13. The cassette integrated catalyst according to claim 1, wherein said at least one depression has a projection height relative to an inner surface of the at least one wall comprising said at least one depression of 0.5 mm-15.0 mm.

14. The cassette integrated catalyst according to claim 1, wherein the catalyst comprises a plurality of monoliths arranged one after the other is serial connection between the first open end and the second open end of the cassette.

15. The cassette integrated catalyst according to claim 1, wherein the catalyst comprises a plurality of monoliths arranged side by side across an internal cross sectional area of the cassette.

16. The cassette integrated catalyst according to claim 1, further comprising a friction enhancing cassette monolith interface.

17. The cassette integrated catalyst according to claim 16, wherein the friction enhancing cassette monolith interface comprises glue.

18. The cassette integrated catalyst according to claim 16, wherein the friction enhancing cassette monolith interface comprises a vibration damping mat material.

19. The cassette integrated catalyst according to claim 1, wherein the catalyst is a NH.sub.3 slip catalyst.

20. A ship engine exhaust system comprising at least one cassette integrated catalyst according to claim 1.

Description

(1) A more detailed description of the invention will be apparent from the following description of a specific embodiment with reference to the drawings in which

(2) FIG. 1 shows an isometric view of the cassette with depressions but without the monolith(s),

(3) FIG. 2 shows an isometric view of a part of the cassette,

(4) FIG. 3 shows a side view of the cassette,

(5) FIG. 4 shows an end view of a part of the cassette,

(6) FIG. 5 shows a detail view of a part of the cassette shown in FIG. 3,

(7) FIG. 6 shows a cut view of a detail of the cassette shown in FIG. 3, and

(8) FIG. 7 shows a detail view of a part of the cassette shown in FIG. 3.

POSITION NUMBERS

(9) 01. Cassette. 02. First open end of cassette. 03. Second open end of cassette. 04. Cassette wall. 05. Cassette depression. 06. Cassette collar.

(10) Referring to FIG. 1, a cassette 01 according to an embodiment of the invention is shown without the monolith(s) inside it. The cassette of this embodiment has a four cassette walls 04 adapted to enclose the sides of the monolith(s) to be mounted inside it and to fix the monolith(s) against movement relative to the cassette. When the monolith(s) are mounted within the cassette, it is adapted to receive a flue gas to be cleaned in the monolith(s) from the first open end of the cassette 02, through the monolith(s) within the cassette and further out through the second open end of the cassette 03.

(11) On each of all four cassette walls are five cassette depressions 05, which can be seen in cut view and in more detail in FIG. 6. In this embodiment, the depressions are arranged perpendicular to the flue gas flow direction from the first to the second open end of the cassette. This provides increased structural strength to the thin-plate cassette walls, which have less tendency to bending and vibrations accordingly. Furthermore, the depressions which in this embodiment are projecting inwards in the cassette towards the monolith(s), provide a well-defined and optimized fix of the monolith(s) which are to be arranged within the cassette. As discussed in the foregoing, in an embodiment where the cassette is enclosing the monolith(s) in a press fit, the depressions may induce a slight deformation of the monolith(s) where the face of the monolith(s) are in contact with the depressions, which causes a strong fix of the monolith(s) in the cassette due to a high friction force and possibly also a mechanical dent/indent lock of the monolith(s).

(12) The cassette showed on FIG. 1 also comprises a cassette collar 06 in both its open ends. In this embodiment the collar is two bends of the cassette wall in a slightly inwards facing S-shape as seen in more detail in FIGS. 5 and 7. This provides additional strength of the cassette wall at the open ends and also provides an end stop for the monolith(s) further securing the monolith(s) against movement in or exiting the cassette.

(13) FIG. 2 shows an isometric view of a half part of the same cassette as shown in FIG. 1, to illustrate the mounting of the cassette around the monolith(s). As seen, the half part is a plate with two 90 bends, enabling the half part to be placed around the monolith(s), which then receives the other half part of the cassette. The two half parts are then pressed together to fit around the monolith(s) and welded along the half part wall edges. In FIG. 3, the half part is shown in side-view, revealing the edges of the half part wall which is suited for welding. The same half part is shown in an end-view in FIG. 4, revealing the two 90 bends and the wall edges.