WO1984004471A1

WO1984004471A1 - Pipe for use in systems with hot gases

Info

Publication number: WO1984004471A1
Application number: PCT/DK1984/000029
Authority: WO
Inventors: Hans Aage Christiansen
Original assignee: Hasle Klinker- & Chamottestensfabrik AS; Hasle Klinker & Chamott
Current assignee: Hasle Klinker- & Chamottestensfabrik AS; Hasle Klinker & Chamott
Priority date: 1983-05-09
Filing date: 1984-04-12
Publication date: 1984-11-22
Anticipated expiration: 1986-10-12
Also published as: DE3490239C2; DK205583A; DK205583D0; EP0143803A1; DE3490239T; US4651783A; GB2149876B; ES532285A0; ES8505074A1; GR79967B; GB8500168D0; GB2149876A

Abstract

In a cyclone for the cleaning of hot gases, the centre-pipe (1) is produced of curved outer and inner elements (7, 8) which are made of fireproof material. The outer and inner elements (7, 8) are suspended in a self-supporting construction in upper end elements (2), and the lower edge of the centre-pipe (1) is provided with lower end elements (14), in that the individual elements are suspended within each other by means of projections (9, 9'), and the upper end elements (2) are suspended in a supporting structure (16) by means of anchoring devices (13) which cooperate with grooves in the upper end elements (2). There is hereby achieved a centre-pipe (1) which is capable of withstanding high temperatures, and which can therefore be used in cyclones for the cleaning of hot gases. Since the centre-pipe is built up of a large number of elements (7, 8, 2, 14), it can be expedient for it to be assembled during the building of the actual cyclone, and thus it becomes much easier and cheaper both to produce and to transport the individual elements.

Description

PIPE FOR USE IN SYSTEMS WITH HOT GASES

This invention relates to a pipe for use in systems which wor with hot gases, i.e., for example, as the centre-pipe in a cyclone for the cleaning of hot gas¬ es or the reaction chamber in a fluid-bed installa¬ tion.

For the separation of particles from currents of air, the use is known, for example, of one or more cyclo¬ nes. A cyclone consists of an upper, cylindrical part and a lower conical part. The air flow is introduced tangentially at the head of the cylindrical part, and continues in a downwardly-directed spiral movement. This is the so-called primary vortex, which continues down towards the nose of the conical part. From here, an upwardly-directed spiral movement emanates, namely the so-called secondary vortex. This leaves the cy¬ clone through an axial outlet, the so-called centre -pipe, at the head of the cyclone.

For reasons of the vortical motion, the particles in the air current are influenced by strong centrifugal forces, whereby they are forced outwards towards the wall of the cyclone. From here they fall downwards towards the nose and are collected in a large con¬ tainer, said container either being changed at suit¬ able intervals or continuously emptied through a sluice.

During the process of lime burning or in the manufac¬ ture of cement, it is desirable to clean the disch¬ arge air from the rotary kiln. A cyclone would be suitable for such cleaning, but commonly-known cy- clones of metal have the disadvantage that the hot discharge gases will ruin the centre-pipe, in that said centre-pipe lies precisely in the path of the flow of hot gases and can be cooled only with great 5 difficulty. The weldings in the centre-pipe will rupture, and the outlet from the cyclone gets blocked by falling material. Furthermore, the cyclone will, of course, be ruined. It has been shown that even metal alloys with high melting points have diffic- Q ulty in withstanding the hot gases.

Moreover, to produce a centre-pipe of such alloy is very costly, in that a centre-pipe for a cyclone for the cleaning of discharge gases from a rotary kiln 5 can, for example, have a diameter of 2-3 metres and a length of 1-2 metres.

Fluid-bed systems are installations in which the par¬ ticle-formed material is held floating in an upwardly 0 -directed flow of air. Such installations are used, for example, in the burning of lime and for other applications where it is desired to expose such mater¬ ials to high temperatures, the reason being that when the material is held in a floating state, it has a 5 very great effective surface.

With such systems, one meets the same problems as those encountered with centre-pipes for cyclones. The material must be held floating in a reaction chamber, ^Q and this must be capable of withstanding very high temperatures.

The object of the invention is to present a pipe which can tolerate even very much higher temperatures, and

O H which can be used for the purposes discussed, and this object is achieved by building the pipe (1) as a self-supporting construction of a ceramic, fire¬ proof material.

Fireproof materials can withstand the high tempera¬ tures without difficulty, and thus by producing the pipe of fireproof material, the resulting pipe can be used for the cleaning of very hot gases. The fact that the pipe is self-supporting means that it can be used in many places, the reason being that the use of foundations and the like is not necessary. More¬ over, what is involved is not a lining but an inde¬ pendent pipe.

If, as presented in claim 2, the pipe is comprised of a large number of elements, the result achieved is that it is not only simple to produce and transport, but also to erect. To produce a pipe of the dimensions mentioned earlier of ceramic material and in one piece is extremely difficult. By constructing the centre- pipe of individual elements of a suitable size, there is thus achieved a considerable reduction in the cost of a ceramic, fireproof pipe.

It is expedient, as presented in claim 3, for the up¬ per end of the pipe to have end elements which are arranged to support the whole of the pipe as a down¬ wardly hanging part. The possibility is thus achieved of a good and safe securing of the pipe. Moreover, this becomes simple to assemble, in that the individ¬ ual parts of the pipe, after the location and secur¬ ing of the end elements, are merely hooked onto said end elements or on the elements already suspended. If the pipe, as presented in claim 4, is composed of outer and inner elements with the same height and with radius curvatures which correspond respectively to the outer and inner circumferences of the pipe, the pipe thus achieved has smooth, even surfaces and, moreover, great mechanical strength.

If, as presented in claim 5, the pipe is made up of outer and inner elements which lie in bonded connec- tion, a very strong pipe is achieved where even the individual elements can break or be removed without the construction collapsing.

It becomes simple to produce the elements if the out- er elements are identical and the inner elements are identical, as presented in claim 6.

If, - as presented in claim 7, the elements have a C-shaped cross-section, said elements are easily as- sembled to produce a pipe in accordance with the in¬ vention.

If, as presented in claim 8, the elements are provid¬ ed with an inclined surface, the result is that the individual elements can be locked together to form a solid construction.

If the projections, as presented in claim 9, are of a height which is substantially equal to 1/4 of the height of the elements, a further solid construction can be achieved in which there will be a minimum of clearance between the individual elements , so that the pipe is also given smooth surfaces. As presented in claim 10, a pipe according to the invention can

OMPI also be characterized by providing both ends of each projection with a raised edge part, the length of which is substantially 1/4 of the length of the ele¬ ment.

There is thus achieved a safe securing in the longi¬ tudinal direction between the individual elements.

As presented in claim 11, a pipe according to the in- vention can be characterized by providing the lower edge of the upper end elements with a projection which corresponds to the projections on the inner and outer elements. A simple assembly of the pipe is thus achieved, in that the outer elements can be hooked directly on the upper end elements.

If, as presented in claim 12, lower end elements are used, the pipe is provided with an advantageous form from the point of view of flow, which is of particul- ar significance when the pipe is used as the centre -pipe in a cyclone.

A simple assembly of the lower end elements is ach¬ ieved if these are as presented and characterized in claim 13.

By providing the lower end elements with a shape as presented in claim 14, simple manufacture is achiev¬ ed.

As presented in claim 15, when assembling the pipe a layer of mortar can be used between the individual elements. Achieved hereby is a strong centre-pipe which also has very even and smooth surf ces. The

O PI

^ATiO≤ mortar also ensures that the elements are held sec¬ urely in engagement with one another.

Finally, it is expedient for a layer of ceramic felt to be provided on the outside of theupper end elem¬ ents, in that this layer will serve to absorb possi¬ ble deformations of the pipe due to thermal expan¬ sion.

The invention will now be described in closer detail with reference to the accompanying drawing, where

fig. 1 shows a vertical section through a cyclone which uses a pipe according to the inven- tion as the centre-pipe,

fig. 2 shows the centre-pipe from the cyclone in fig. 1, seen on a larger scale,

fig. 3 shows a vertical section through an outer element according to the invention,

fig. 4 shows a vertical section through an end element according to the invention,

fig. 5 shows a vertical section through a lower end element,

fig. 6 shows an outer element according to the invention, seen from the inner side, and

fig. 7 shows a pipe according to the invention under construction.

OMPI In fig. 1 is shown a cyclone having a cylindrical part 3 and a conical part 4, where it is expedient for both of these parts to be made of metal. The air or gas to be cleaned is introduced radially through an injection opening 6, and thus a primary and a sec¬ ondary vortex will arise in the cyclone chamber 15. Particles in the gas will accumulate at the outlet 5 which can be provided with a sluice, and from where they can be removed in a known manner. The cleaned gas will leave the cyclone through the centre-pipe 1, which according to the invention is made of a ceram¬ ic and fireproof material which is capable of with¬ standing the very high temperatures which arise in the production of, for example, burned lime or cem- ent.

The centre-pipe is shown in more detail in fig. 2. The centre-pipe 1 consists of upper end elements 2, outer elements 7, inner elements 8 and lower end el- e ents 14. All of these elements are hooked together in a self-supporting construction. The fireproof el¬ ements have, in fact, such a great mechanical stren¬ gth that it is possible to suspend the whole of the centre-pipe from the upper end elements 2. These are provided with grooves in which the anchoring devices 13 can be engaged. The anchoring devices 13 are moun¬ ted on a steel construction 16 which supports the whole cyclone, but it is equally possible to secure the end elements 2 to the cyclone itself.

The outer elements 7 and the inner elements 8 are arcuate in shape, thus when placed together they form a cylindrical pipe. Both the inner as well as the outer elements 7, 8 have a C-shaped cross-section

_ OMPI with two horizontal projections 9, 9'. These projec¬ tions 9, 9' are of a height which is 1/4 of the height of the elements. The elements are assembled to. form a centre-pipe 1, in that the individual elements are hooked together and in that the end elements 2 sup¬ port all the remaining elements. The individual ele¬ ments are of a size which makes both their manuafct- ure and transport expedient. It will be obvious that the elements are capable of being transported separ- ately, and then assembled to form the centre-pipe in the construction of the cyclone itself. This assembly is made very simple by virtue of the projections 9, 9' , in that subsequent elements are merely hooked onto those already suspended.

Since the height of the projections 9, 9' is 1/4 of the height of the elements, the elements 7, 8 can be hooked together in bonded connection to form a sur¬ face with a minimum of joint space. It can be exped- lent for the elements to be displaced in relation to each other in their longitudinal direction. Each el¬ ement will thus be suspended in two elements hanging above it, and will itself support two elements hang¬ ing below it, the result being that each element will be in connection with four surrounding elements. The construction thus achieved is very solid, even though the centre-pipe is built up of elements. Should some of the individual elements break or lose their sup¬ porting ability, the centre-pipe will nevertheless remain hanging together.

In order to produce a smooth edge at the centre -pipe's lower edge, lower end elements 14 are mount¬ ed. It is important that the lower edge of the centre

OMPI ΛPO -pipe 1 has an even surface, the reason being that it is desirable to have as much control as possible over the flow in the cyclone. The shape of the lower end elements 14 is the same as that of the upper half of the inner elements 8, but many other shapes are pos¬ sible.

In order to produce smooth surfaces on the centre -pipe 1, so that the course of flow is as uniform as possible, the space between the individual elements can be filled with mortar, said mortar being of a suitably alkali-resistant type. This will naturally also increase the strength of the centre-pipe 1. Sim¬ ilarly, it is envisioned that the mortar used will be of a kind which is capable of withstanding the high temperatures which will arise.

As can be seen particularly in figs. 3, 4, 5 and 6, ^' the projections are provided with an inclined surf- ace 10, 10'. The effect of this surface is that the elements are held securely together, the reason being that the elements lock together when being assembled. As shown in fig. 6, the projections 9, 9' are also provided with a raised edge portion 18, 18', the length of which is 1/4 of the total length of the element 7. By means of these raised edge portions 18, 18 ' , a similar locking effect is achieved in the ele¬ ments' longitudinal direction. When the centre-pipe 1 is correctly assembled, it will therefore be very strong.

Except for its curvature, the outer element 7 shown in- fig. 3 is identical to the inner elements 8. The upper end element 2, which is seen in fig. 4, is pro- vided with a groove 12 which engages with an anchor¬ ing device. The elements 2 are also provided with a projection 11 which, in shape and size, corresponds to the projections on the remaining elements.

The lower end element 14 shown in fig. 5 has a pro¬ jection 17 which similarly corresponds to the pro¬ jections on the remaining elements. The shape of this element is the same as that of a half-part of one of the remaining elements.

In fig. 6 is seen an outer element 7 seen from the inner side. Although the above-mentioned raised edge portions 18, 18* are shown only in connection with an outer element 7, it is obvious that such raised edge portions are to be found on all projections. An att¬ empt to illustrate this has been made by means of the stippled lines in figs. 3, 4 and 5.

In fig. 6 is shown a pipe according to the invention under construction. The individual elements are dis¬ posed in bonded connection in both the vertical and the horizontal plane.

As it will also appear from figs. 1 and 2, it will be seen in fig. 6 that the end elements 2 are consider¬ ably stronger than the remaining elements. The reason is that the upper end elements 2 must be able to bear the whole of the centre-pipe 1. In the drawing is shown only that part of the centre-pipe 1 which ex¬ tends into the cyclone chamber 15. Of course, it will be clear that in practical application the centre-pipe 1 must be led either to a discharge opening or to a further cyclone. If required, there is nothing to prevent the centre-pipe also outside the cyclone from being made of fireproof material.

The individual elements are capable of being provid- ed with many different forms. The embodiment shown in the drawing is merely an example which, in many cas¬ es, it will be expedient to follow. In the event of special cyclone constructions being necessary to ach¬ ieve a sufficiently good cleaning of the gas, the centre-pipe according to the invention can, of course, be formed in the most expedient manner.

It is similarly obvious that the centre-pipe accord¬ ing to the invention can be used in all places where it is desired to remove particles from hot gases, and not only with rotary ovens for the manufacture of cement.

The centre-pipe can, for example, be made of the moulding material D 52 A, which is manufactured by Hasle Klinker- og Chamottestensfabrik A/S, but it is naturally also possible to use any other material which can be moulded and is capable of withstanding the thermal loads.

Finally, it must be emphasized that the pipe accord¬ ing to the invention can also be used in many other places. We have already mentioned fluid-bed instal¬ lations. However, the pipe can be used in all places where, for one reason or another, there is use for a pipe which can tolerate the very high temperatures. The essential factor is merely that the pipe is self -supporting and made of ceramic material. According to the invention, such a pipe can, in fact, be pro- duced in practically all dimensions

Claims

C L A I M S

1. Pipe for use in systems which work with hot gases, i.e., for example, as the centre-pipe in a cy¬ clone for the cleaning of hot gases, or as reaction chamber in a fluid-bed installation, c h a r a c t - e r i z e d in that the pipe (1) is built up as a self-supporting construction of a ceramic, fireproof material.

2. Pipe according to claim 1, c h a r a c t e r - i z e d in that it is composed of a large number of elements.

3. Pipe according to claim 3, c h a r a c t e r ¬ i z e d in that the upper elements in the pipe are end elements arranged to support the whole of the pipe as a downwardly-hanging part.

4. Pipe according to claims 2 or 3, c h a r a c t ¬ e r i z e d in that the pipe 1 is comprised of out- er and inner elements (7, 8) of the same height and with curvature radii which correspond respectively to the outer and inner periphery of the pipe (1) .

5. Pipe according to claim 4, c h a r a c t e r - i z e d in that the outer and inner elements (7, 8) lie in bonded connection.

6. Pipe according to claims 4 or 5, c h a r a c t ¬ e r i z e d in that the outer elements (7) of the pipe (1) are identical, and in that the inner elem¬ ents (8) of the pipe (1) are identical.

7. Pipe according to claim 6, c h a r a c t e r ¬ i z d in that both the outer as well as the inner elements (7, 8) have a C-shaped or hook-like cross -section with two horizontal, outwardly-extending

5 projections (9, 9') .

8. Pipe according to claim 7, c h a r a c t e r ¬ i z e d in that each projection (9, 9^T) , on that side which faces towards the centre of the element, 0 is undercut to form an inclined surface (10, 10') .

9. Pipe according to claims 7 or 8, c h a r a c t ¬ e r i z e d in that the height of the projections (9, 9') is substantially equal to 1/4 of the height 5 of the elements (7, 8) .

1Q. Pipe according to claims 7, 8 or 9, c h a r a c¬ t e r i z e d in that at both ends of each projec¬ tion (9, 9') there is provided a raised edge portion 0 (18, 18'), the length of which is substantially equal to 1/4 of the length of the element.

11. Pipe according to claims 3 - 10, c h a r a c t ¬ e r i z d in that at the lower edge of the upper 5 end elements (2) there is provided a projection (11) which corresponds to the projections (9, 9') on the inner and outer elements (7, 8) .

12. Pipe according to claims 2 - 11, c h a r a c t - Q e r i z e d in that the pipe (1) has lower end ele¬ ments (14) for the formation of an evenly-progressing and smooth undersurface.

13. Pipe according to claim 12, c h a r a c t e r - i z e d in that at the upper edge of the lower ele¬ ments (14) there is provided a projection (17) which corresponds to the projections (9, 9') on the inner and outer elements (7, 8) .

14. Pipe according to claim 13, c h a r a c t e r ¬ i z e d in that the lower end elements (14) are of the same shape as the upper half-part of an inner or outer element.

15. Pipe according to claims 2 - 14, c h a r a c t ¬ e r i z e d in that a layer of mortar is laid be¬ tween the individual elements.

16. Pipe according to claims 2 - 15, c h a r a c t ¬ e r i z e d in that the outside of the upper end elements (2) is provided with a layer of ceramic felt or mineral wool or the like.