FR2611257A1 - STRUCTURAL BRICKS, INCLINED AND GRIDS MANUFACTURED THEREFROM FOR HEAT RECUPERATORS ADAPTED TO INDUSTRIAL FURNACES, ESPECIALLY IN STEELWORK - Google Patents

Abstract

A) INCLINED STRUCTURAL BRICKS AND GRILLS MANUFACTURED FROM THESE FOR HEAT RECOVERERS SUITABLE FOR INDUSTRIAL OVENS, ESPECIALLY IN STEEL INDUSTRY. B) CHARACTERIZED IN THAT THE ROOF SURFACE 5 IS OFFSET IN AT LEAST ONE LATERAL DIRECTION ADVANTAGEALLY PARALLEL TO THE BASE SURFACE 4 SO THAT THE STRUCTURAL BRICK IS SHAPED AT AN INCLINE AND THAT THE OFFSET OF THE SURFACE OF THIS ROOF IN RELATION TO THE BASE SURFACE IS SHOWN IN A WAY THAT PROJECTION 8 OF THE CENTER OF GRAVITY 7 OF THE STRUCTURAL BRICK IS LOCATED ON THE BASE SURFACE 4.

Description

-1 Structural bricks, inclined and grilles manufactured at

  from them for suitable heat recovery

  industrial furnaces, especially in the iron and steel industry ".

The invention relates to a brick of

  refractory material structure for recovery grates

  heat exchanger with a cruciform or

  as well as a base surface and a roof surface where each recuperator is connected for heat recovery by a connecting channel for an agent stream to an industrial furnace, and a stack which has been manufactured

  by use of the structural bricks of the invention.

  Industrial ovens means the installations

  in the iron and steel industry, for example

  Siemens or glass melting furnaces heated by flame.

  To obtain a mass capable of

  accumulate heat at high specific volume as well as to obtain a significant heat exchange between the

  structural bricks of the recuperator and the working

  pouring these recuperators, we know a number

  of structural bricks and the like for installations

  recovery heat recovery

  high temperature processes. In addition, conditions

  important additional features such as stability, breaking strength and other mechanical

  and fluidics must be maintained.

We know a structural brick

  of rectangular shape which is used for

  waste collectors in different structural techniques, such as closed chimney, basket net or wire mesh assemblies. Its disadvantage

  is that it is very rough for the materials.

  In recent times, we have realized for this reason bricks of structure more and more different in practice, which for a expenditure in lower material realize specific heating surfaces

  more important and despite their wall thickness

  pick, exhibit a high stability, as described, for example a right cruciform brick, in the publication GLASTECHNISCHE BERICHTE 51, 1978, pages

203 to 211.

  In the publication SPRECHSAAL 119, 1986, delivery 2, page 142 and following, it has been described

  a diamond brick that represents a crucifix brick

  shape whose wings are decreasing towards the outside.

  It is also known from the patent

  vet DE-AS-29 34 208 a brick hollow or pot-shaped structure that allows thanks to a tubular structure

  which surrounds the flow well, in the same way

  a stable stump that saves materials through a straight flow path. The hollow structure brick has been modified several times. So for

  improving heat transmission through

  and to allow transverse flow, lateral break points were placed. We know

  also hollow structural bricks with over-

faces having grooves.

  Structural bricks and bricks

  However, on the basis of a smooth chimney structure, the hollow structure patterns have a relatively unsatisfactory convective heat transfer behavior. Indeed, resistance to heat transfer by convection represents 60 to 70% of the main fraction with respect to the resistance to the total heat transfer for such heat transmitters and is not influenced decisively by the modifications mentioned above (conicity of

  wings, break points, grooves), the conicity of the

  the bricks in the lamination, which must be sought for the edges of blanks and the effects of turbulence, is inefficient because of the longer introduction time, because of additions, agglomerates

and deposits.

  The object of the invention is to create structural bricks for the stacks in recuperators, so that the heat transfer

  convection is improved and that we can achieve

  save money on materials and energy. In addition, new construction structures must be created

  less cumbersome collectors and stacks.

  To this end, the invention proposes to create a structural brick for stacks of

  recuperators which guarantee that on types of structure

  re, flow wells can be formed, making it possible repeatedly to invert flue gas

  or current of air with a strong turbulence, a

  adjacent and high heat exchange. By using

  structural bricks, a guide must be obtained.

  the flow medium in the same way as homogenous exploitation and solicitation of all

the wells of a recuperator.

  This problem is solved according to the

  provided by a structural flange characterized in that the roof surface is shifted in at least one lateral direction advantageously parallel to the base surface so that the structural brick is formed in an inclined manner and the offset of the surface this roof relative to the base surface is such that the projection of the center of gravity of the structural brick is on the base surface, and is not fundamentally related to a particular sectional shape. In addition, a brick of

  structure that can be used for stacking wells

  which in the stack reverse the current of the

  take place in a desired direction or provide a stable change of direction, so that the current of the medium is well turbulence. The turbulence of the flowing medium entails a heat exchange

  high between the stack and the middle current. We ob-

  holds an advantageous form of the structural brick which before all things allows a smooth or flat filling of the wells of stacks or serves during the return

  U-shaped channels to fill the pores in the stack

  if the roof surface and the base area are

  inclined relative to one another in a manner

  the angle of inclination can be up to 90.

  By using structural bricks according to the invention

  tion, it is possible to create stacks of

  stable, thin-walled and cost-saving

  and space. Such a stack of recuperator is obtained

  holds if we use the sloping structure bricks

  with slopes of the same orientation or

  changing with each other. If we start from the direction of the main flow of the media when executing directional changes, we obtain an appropriate disposition in the direction of the turbulence and the adjacent current, if the changes of direction of the wells of stacks are by report to the

  main direction of the alternating current

liers and zizag.

Satisfactory stacking is achieved

  from the point of view of heat exchange and

  turbulence if the sloping structural bricks are used

  born successively or in combination with bricks of

  straight structure. Because between the structural bricks

  In the inclined position, straight bricks are inserted in the appropriate position, so that between the zig-gas sections of one or more stacking wells at least one

  rectilinear section, there are also zones of

  blimation for specific constituents of flowing media. These sublimation zones are in the straight section of straight structural bricks

  in which there is less turbulence, in the-

  however, the partial constituents mentioned go from the gaseous state to the solid state without having the opportunity

  to precipitate. The particles thus obtained are

  arising from a relatively laminar and ex-

  pulsed. The invention also includes the

  particular case of a single-channel recuperator.

  For use and solicitation

  uniformity of all stacks wells for

  unmodified recovery dimensions, it is advan-

  tageux 3i the structural bricks inclined advantageous-

  placed in the recuperator on straight structural bricks, that they protrude into the

  linkage with the industrial oven and be inclined

  born in relation to it. In this way, the openings

  Wells in the connecting channel are oriented more than heretofore to the middle stream and are better adapted to the direction of the main stream of the medium in the connecting channel. This concerns both the flue gas stream from the industrial furnace to the recuperator and the combustion air stream from the recuperator to the industrial furnace. An advantageous form of the invention is characterized in that at least a part of the stacking wells with a growing gap for

  Industrial furnaces has a great length. By use

  of inclined bricks with roof and base surfaces parallel to each other, we obtain a

  stepped staggering of the ends of

  each step detecting a portion of the gases from

  smoke and the wall facing the step of

  following pings representing the rebounding surface

  for the partial flow of gas that is directed at a step in or immediately before the stacking well (s). The lowest stacking step is the closest to the oven and the highest step is located furthest from the oven. Another improvement of the invention is that

  stacking wells unevenly inclined, but

  placed regularly, are extended so that the input and output faces of the currents in the middle of the stack, the roof surfaces of the inclined structural bricks disposed at the ends of the well are placed in a plane substantially at right angles to relative to the direction of the main flow in the connecting channel. The average inclination or inclination

  the influx surface of the stack cooperates with the

  the construction of the connecting channel, so that the influx of media and thereby the distribution of pressure over the entire inflow surface is practically regular. This state of affairs represents a

  important condition for the crossing of

  relatively regular in the whole of the world.

stacking.

The invention will now be ex-

  in more detail with the help of the schematic figures representing eight exemplary embodiments. These show: - Figure 1, the front view of a sloping cruciform structure brick; - Figure 2: the side view of Figure 1 - Figure 3, the plan view of Figure 1; Figure 4, the front view of a sloping hollow structure brick; Figure 5, the side view of Figure 4; - Figure 6, the plan view of Figure 4;

  FIG. 7, in longitudinal section, part of a first

  first stacking well obtained by using a

  that of structure according to the invention; - Figure 8, in longitudinal section, a portion of a second stacking well obtained by using a structural brick according to the invention; - Figure 9, a portion of a stack in a longitudinal section; - Figure 10, a longitudinal section through the upper part of a recovery stack; - Figure 11, a longitudinal section through the upper part of a stack having a stepped influx surface; Figure 12, a longitudinal section through the upper part of a stack having a vertical influx surface. In Figures 1, 2 and 3, we can see a structural brick 1 whose wings 2 and 3 are

  cross at right angles and commonly include

  base face 4 and a roof surface 5. The structural brick 1 has in the crossing zone of the wings 2 and 3 a geometric axis 6 which is shown in FIGS. 1 to 3 by its extensions and lies in the

  between the roof surfaces 5 and 4 at the center

  7 of the brick 1. The roof surface 5 is inclined on the base surface 4 in two lateral directions, so that is constituted a brick of cruciform structure inclined in two directions of which

  the projection 8 of the center of gravity 7 is at the in-

  4 of the base surface 4. The structural brick 1 is provided on its base surface 4 with grooves 9 and on

  its roof surface 5 springs 10 which promote the

  appearance and stability of a stack thus obtained.

  FIGS. 4, 5 and 6 show an annular octagonal hollow structure brick 11 comprising an envelope 12 which comprises a surface

  1 "and a roof surface 14 respectively provided with

  grooves 15 and springs 16, which facilitate the construction of a stack and must increase its stability. The structural brick 11 has an axis of symmetry 17 between the base surface 13 and the surface of

  roof 14, in the middle of which is the center of

  18. The roof surface 14 is inclined in a di-

  on the base surface 13, so that the

  Jection 19 of the center of gravity 18 lies within the

  of the base surface 13, and that a structural brick

  inclined ture originates in one direction.

  The dimensions of structural bricks

  2 ture inclined 1 and 11 may correspond to those of known straight structure bricks. The base surfaces 4 and 13 intervening for the position of the projections 8 and 19 also determine the surfaces between the wings 2 and 3 and the surfaces surrounded by the envelope

  12 in the projection plane of Figures 3 and 6.

  Fig. 7 shows hollow inclined structural bricks 21 to 24 which are placed relative to each other in opposite directions

  different, and form a stacking well.

  place 26 passes through the well 25 corresponding to the wave-shaped directional changes, o from the ridges 27 protruding into the well 25, energetic turbulences and an adjacent stream are produced.

  so that the heat transfer effect is improved

  at least 30%. The orientation changes has from well 25 relative to a main direction 29 of

  middle 26 vary regularly and reach 30.

In Figure 8, a stacking well

  30 has zigzag portions 31, 32 with hollow structure bricks and a straight portion 33 with straight structural bricks. While in the zigzag portions 31, 32, inclined structural bricks are created with a regular variation a = + 45 of the orientation of the stacking wells 30 with respect to a main flow direction 34. a flowing gaseous medium, the change of orientation of the straight portion 33 relative to the last section of the zigzag portion 31 or the first section of the zigzag portion 32 relative to the straight portion 33 reaches 45, so that the straight portion 33 is parallel to the direction of the main flow 34. In the

  sections zigzag 31, 32, occurs a strong turbulence

  flow medium 35 on the edges 36 which

  is caused by successive orientation changes.

  On the other hand, the current of the medium 35 is relatively laminar in the right part 33. At the passage between the zigzag part 31 and the right part 33, the medium 35

  which is introduced into well 30 correspondingly

  te at a high temperature and who for example is disembarking

  The passage of the right part 33 to the zigzag part 32, the temperature of the flowing medium is still 800 C. In this temperature range, the sulphate fraction passes from the right part 33 to the zigzag part 32. the gaseous state in the solid state to form particles which through the relatively homogeneous medium stream in the straight portion 33 do not precipitate or agglutinate. On the other hand, large sulphate precipitates could be formed due to the heterogeneous behavior of the

  middle 35 on the section in a zigzag area rem-

  placing a straight zone, which could lead to

the traffic jam.

  In FIG. 9 are arranged in a recuperator casing 39, three channels 41, 42, 43 formed from straight structural bricks and

  clinches 39, 40, 37, through which flows the

  gaseous sites 44, 45, 46. The roof surfaces of the sloping structural bricks 37 form with their base surface an angle of 90, so that a section is formed.

  triangular. In the area of structural bricks

  40, 37 occurs several changes of di-

  rection of the media 44, 45, 46 in the channels 41, 42, 43 and thereby turbulence and an adjacent current which causes a greater heat transfer of

  environments (flue gas) 44, 45, 46 on the walls of

  41, 42, 43, or a heat input to the media (combustion air) 44, 45, 46 from the walls of these same channels 41, 32, 43. Supply and heat transfer have

  place alternately and successively.

  According to Figure 10, a recuperator 48 equipped with a stack 47 is connected by a connecting channel 49 having an oblique surface 50 to a melting furnace 51 shown only in part. The stack 47 has at its portion facing the connecting channel 49 sloping structure bricks 52 which define the inclined ends 53 of the well of the stack 54

  and a planar inflow surface 55 for a listening medium.

  56. The connecting channel 49 is provided with a

burner pitch 57.

  Because the well ends 53 are inclined relative to the stream of media (flue gas) 56, it already enters the well 54 closest to the melting furnace 51, so that they are also distributed for the heat exchange in a manner similar to those of wells

  the farthest from the melting furnace. A structure corresponding to

  of the connecting channel 49, in particular a

  oblique position and appropriate dimensions of the sur-

  inclined face 50 increase this effect.

  In FIG. 11, a recuperator 58 connected by a connecting channel 59 to a not shown melting furnace is described, similarly to FIG. 10, the flue gases (exhaust gas) flowing in the recuperator 58. The latter comprises a stack 61 in vertical straight structure bricks which at its part

  superior in part 62 protruding from

  The link is transformed into a stack from the structural bricks inclined on the exhaust gas stream 60. The sloping structure bricks of the

  part 62 are cruciform, arranged in tiers and

  the stacking well 63 having a growing gap from the melting furnace placed as on the

  Figure 10 with increasing length.

  By the stepped arrangement and the conformation of the upper portion 62 of the stack 61, all the openings 64 of the stacking wells 63 are regularly in the reverse flow of the exhaust gases 60, the partial reversals of which occur. first on the oriented surfaces of the cruciform bricks 65 and then on an oblique surface 66 of the

link channel 59.

  In FIG. 12, an extractor 68 equipped with a vertical stack 67 connected by a connecting channel 69 is analogously described in FIG.

  to a melting furnace not shown. Wells 70 of the

  67 are placed obliquely at their upper

  in part 71 protruding into the canal of

  link 69 below an inclined surface 72 and

  on an end plane 74 in which their openings are located at least approximately at right angles to the direction of the main flow 73.

  the implementation of part 71 of stack 67 com

  With the oblique wells 70, hollow structural bricks inclined at 45 have been used, the roof surfaces 75 and the base surfaces 76 being parallel to one another. In order for the openings of the wells 70 to be in a plane 74, inclined structural bricks 77 are put in place as a stop, whose roof surfaces 78 form an angle of 90 with the base surfaces. A flow of media 80 coming out of the melting furnace

  penetrates through the connecting channel 69 into the openings

  tures of the oblique wells 70 and impact, whereby it is distributed on the individual wells 71, 70 substantially homogeneously on each of them. The exchange

  between the medium stream 80 and the stack 67 is

  once by the release of heat or the heating

  desired and also by precipitates and

unwanted corrosions.

  The invention is not limited to the dimensions and the proportions of the inclined structure Drives of FIGS. 1 to 6. It is also possible to provide cavities with structural bricks inclined in their wings and their envelope surface and / or change the shape of their section. The inclination of structural bricks is related to no specific angle only when it is sufficiently ensured that stability and strength are not adversely affected,

  nor their complicated manufacture and their assembly

  unfavorably influenced, as well as resistance to

  erosion. Stacking wells can be made obliquely in two planes instead of one. In place of the representation of FIG. 11, in which there are mainly two stacking wells 63 on a step, the staggering may also be predetermined from stacking wells with a stacking well. It is also

  It is possible to stagger only the part of the

  pilling which is not in the vicinity of the oblique surface 66, in an individual plane. In FIG. 12, the stack 67 can also be introduced on the influx plane 74 in addition to the horizontal domain of the connecting channel 69. In addition, the influx planes 74 of the stream of the medium 80 are rejected at the same time. 'opposite. Finally, it is possible to place the oblique structural bricks so that their slopes extend in different directions so that also the slopes of the bricks do not determine a single plane as described on the drawings.

Figures 7 to 12.

Claims (8)

R E V E N D I C A T I 0 N S   1) Refractory structural slab bricks for heat recovery grates with cross-section or annular section as well as a base surface and a roof surface where each recuperator is connected for heat recovery through a connecting channel for a agent stream to an industrial furnace, characterized in that the roof surface (5)   is shifted in at least one lateral direction   gently parallel to the base surface (4) so   that the structural brick is formed in a   and that the offset of the surface of this roof relative to the base surface is such that   the projection (8) of the center of gravity (7) of the   that of structure is located on the base surface (4).   2) Structural brick according to the   1, characterized in that the base surface (4) and the roof surface (5) are inclined one by report to the other. 3) Stacking for the implementation   sloping structural bricks according to the   cation 1, characterized in that the structural bricks   slants are arranged alternately with inclinations   sounds directed down the well.   4) Stacking that was obtained at   from the sloping structural bricks of the   cation 1, characterized in that the sloping structural bricks are arranged with the same inclination towards well.   5) Stacking according to any one   claims 3 and 4, characterized in that the   inclined structures are combined with straight structure.   6) Stack according to the claim   5, characterized in that the sloping structure bricks   are arranged on the structural bricks in the recuperator, protrude into the connecting channel (69)   and are inclined towards the industrial furnace.   7) Stack according to claim 6, characterized in that the roof surfaces of the sloping structural bricks are arranged in the connecting channel (69) at the ends of the well in stages from which the lowest stage is placed most near the industrial furnace and the highest floor, as far away from this last.   8) Stacking according to any one   claims 6 and 7, characterized in that the sur-   Roof faces of sloping structural bricks are   at the ends of the well in the connecting channel in   a plane practically perpendicular to the direction of the main environment.