BE858730A

BE858730A - METHOD AND DEVICE FOR INCREASING THE CALORIFIC EXCHANGES BETWEEN SOLID MATERIAL AND GAS, IN A ROTARY CEMENT OVEN

Info

Publication number: BE858730A
Application number: BE180935A
Authority: BE
Original assignee: Obourg Sa Ciments
Priority date: 1977-09-15
Filing date: 1977-09-15
Publication date: 1978-01-02

Description

       

  Procédé et dispositif pour augmenter les échanges calorifiques

  
 <EMI ID=1.1>   <EMI ID=2.1> 

  
d'utiliser^ pour accroître les échanges calorifiques entre la.. matière solide en fines particules et les gaz, divers dispositifs

  
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à la partie inférieure du four. De tels dispositifs sont par ;

  
exemple constitués de palettes ou de godets releveurs en acier, 

  
ou encore de croisillons en briques rêfractaires . Ces dispositifs entraînent la matière solide sur un parcours relativement réduit 

  
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En effet, il est important en vue d'obtenir un bon rendement ' d'accroître au maximum les échanges calorifiques entre matière 

  
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four, se limitent principalement à la surface du talus en contact avec les gaz. 

  
Les dispositifs utilisés à ce jour et mentionnés cidessus présentent cependant le grave inconvénient de mettre en suspension dans les gaz une grande quantité de fines particules solides, de sorte qu'à la sortie du four les gaz présentent une teneur en poussière très élevée. On est'alors obligé de prévoir un dépoussiérage important des gaz avant de les libérer dans  l'atmosphère. 

  
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inconvénients en prévoyant un procédé et un dispositif qui, d'une part, permettent d'utiliser au maximum les échanges calorifiques par rayonnement et par conduction et, d'autre part, évitent la mise en suspension de particules de poussière dans une région  proche du centre du fours c'est-à-dire à l'endroit où les gaz

  
ont leur vitesse la plus élevée'. 

  
Le procédé suivant l'invention, utilisable dans les fours rotatifs à ciment qui pivotent autour d'un axe central et dont la paroi interne, en contact avec la matière, effectue donc symétriquement par rapport au plan vertical passant par l'axe du  four, un parcours ascendant et un parcours descendant, se carac- ; 

  
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de la paroi,  " prélever clans ce&#65533; premier talus uns certains quantité de 

  
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sur la partie du parcours ascendant au-delà du talus et  sur une partie du parcours descendant, 
- libérer cette quantité de matière à proximité de la paroi <EMI ID=15.1> 

  
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constituer par la chute de la matière libérée au moins un

  
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dant de la paroi du four. 

  
L'invention a également pour objet le dispositif

  
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L'invention sera mieux comprise en se reportant à

  
la description en même temps qu'au dessin annexe qui représente, . uniquement à titre d'exemple, un mode de réalisation de l'invention et dans lequel 
- la Figure 1 est une coupe transversale dans un four ; rotatif à ciment comportant le dispositif de l'invention, <EMI ID=20.1> 

  
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; de l'invention. 

  
Suivant le mode de réalisation représenté au dessin, la virole 1 d'un four rotatif à ciment comporte sur sa paroi interne une série de godets 2 répartis à intervalles angulaires égaux. Ces godets comportent chacun une ouverture 3 située vers ;

  
l'avant considéré dans le sens de rotation 4 de la virole. 

  
L'ouverture 3, adjacente à la paroi interne 5 de la  virole, est suivie d'une paroi avant 6, tandis qu'à l'arrière est prévue une palette brasseuse 7, l'extrémité supérieure de la paroi avant 6 et de la palette brasseuse 7 étant jointes par une 

  
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dans le talus, et est rempli progressivement de matière au fur et

  
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en sens Inversa du sens de rotation, et constituant la paroi

  
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four, -la, matière .est . autorisée à s'écouler en contact direct avec

  
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sur une partie importante du -parcours de la paroi, en étant sou- 

  
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tout en étant, maintenue à l'abri d'un contact direct avec ces  derniers . 

  
Des résultats satisfaisants sont obtenus lorsque le

  
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paroi avant de ce dernier a atteint une position angulaire située '

  
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godet et la forme de celui-ci ont été -étudiés pour permettre un remplissage* -convenable par la ratière prélevée dans le talus [deg.]et

  
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minée du godet-. 

  
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 <EMI ID=47.1>  .mine du parcours descendant la paroi du four, ou encore des  godets articulés agencés pour prélever dans une_ certaine { <EMI ID=48.1>   <EMI ID=49.1> 



  Method and device for increasing heat exchange

  
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to use ^ to increase the heat exchange between the solid matter in fine particles and the gases, various devices

  
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at the bottom of the oven. Such devices are by;

  
example made of steel pallets or lifting buckets,

  
or even bricks in refractory bricks. These devices entrain the solid material over a relatively short path

  
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In fact, in order to obtain a good yield, it is important to increase the heat exchange between matter as much as possible

  
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furnace, are limited mainly to the surface of the slope in contact with the gases.

  
The devices used to date and mentioned above however have the serious drawback of suspending a large quantity of fine solid particles in the gases, so that at the outlet of the furnace the gases have a very high dust content. We are then obliged to provide for a significant dust removal of the gases before releasing them into the atmosphere.

  
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disadvantages in providing a method and a device which, on the one hand, allow maximum use of heat exchange by radiation and by conduction and, on the other hand, prevent the suspension of dust particles in a region close to the center of the furnace, i.e. where the gases

  
have their highest speed '.

  
The method according to the invention, which can be used in rotary cement kilns which pivot about a central axis and whose internal wall, in contact with the material, therefore performs symmetrically with respect to the vertical plane passing through the axis of the kiln, an ascending course and a descending course, is charac-;

  
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of the wall, "take from this first embankment a certain quantity of

  
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on the part of the ascending course beyond the embankment and on part of the descending course,
- release this quantity of material near the wall <EMI ID = 15.1>

  
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constitute by the fall of the material released at least one

  
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from the oven wall.

  
The invention also relates to the device

  
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The invention will be better understood by referring to

  
the description together with the accompanying drawing which represents,. purely by way of example, one embodiment of the invention and in which
- Figure 1 is a cross section through an oven; cement rotary comprising the device of the invention, <EMI ID = 20.1>

  
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; of the invention.

  
According to the embodiment shown in the drawing, the shell 1 of a rotary cement kiln comprises on its internal wall a series of cups 2 distributed at equal angular intervals. These buckets each have an opening 3 located towards;

  
the front considered in the direction of rotation 4 of the shell.

  
The opening 3, adjacent to the internal wall 5 of the shell, is followed by a front wall 6, while at the rear is a stirring pallet 7, the upper end of the front wall 6 and of the stirring pallet 7 being joined by a

  
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in the slope, and is gradually filled with material as it

  
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in reverse direction of the direction of rotation, and constituting the wall

  
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oven, -the, matter .is. allowed to flow in direct contact with

  
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over an important part of the course of the wall, while being

  
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while being, kept away from direct contact with them.

  
Satisfactory results are obtained when the

  
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front wall of the latter has reached an angular position situated '

  
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bucket and the shape of it have been -studied to allow a suitable filling * -by the dobby taken from the slope [deg.] and

  
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mined bucket-.

  
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 <EMI ID = 47.1> .mine of the path descending the wall of the furnace, or even articulated buckets arranged to take from a certain {<EMI ID = 48.1> <EMI ID = 49.1>

Claims

keep this quantity of material prisoner at least:

on the part of the ascending course beyond the embankment and

on a part of the descending route ^

- release this quantity of material near the wall of the furnace in the descending path from the moment when

_ second slope of solid material, in the downhill course

te to:

- form a first slope of solid material, offset in the direction of rotation of the furnace following the ascending path, <EMI ID = 57.1>

- .. - take a certain quantity of <EMI ID = 59.1> <EMI ID = 60.1> from this ramier slope

descending course of the furnace wall, the surface of which is

in direct contact with gas.

release of solid matter, entrained on a path close to; and substantially parallel to that of the furnace wall, begins when said solid material has passed through an arc

oven, descending route.

tion of solid matter begins when said solid matter has traversed an arc of a circle of 60 [deg.], with respect to the plane

of which is mounted at least one bucket provided with an opening

lower part of the furnace, a certain amount of solid dobby, the bucket being arranged to retain this amount of solid matter in the part of the upward path beyond the slope and in a part of the downward path, and release it into the

the center of the oven is far enough apart.

6. Device according to 5, characterized in that the go-: det is integral with the rotating wall of the furnace and comprises, the front being considered in the direction of rotation of said wall,

cente to the wall of the furnace, a rear wall ending in the

rear, and side walls closing the sides of the bucket for

rear, upper and front of the bucket following a pivoting of the latter in connection with the rotation of the oven, and an overflow of the. material taken through the opening as soon as the bucket has reached an inclination corresponding to an angular position of the bucket at least 45 [deg.] beyond the vertical midplane of the furnace in the descent path.

7. Device according to 6, characterized in that the interior space of the bucket and the opening are arranged so that the overflow of material begins when the bucket has reached an inclination corresponding to an angular position at 60 [deg.] Beyond of the vertical median plane of the furnace, in the descent path.

8. Device according to any one of claims 5 to 7, characterized in that the oven comprises a series of cups distributed at equal angular intervals on its internal wall.

9. Device according to any one of claims 6 to 8, characterized in that the front wall of the -odet is inclined in the direction of rotation to form a funnel vis-à-vis the opening when passing through the slope, while the rear wall is inclined in the opposite direction to the direction of rotation to first constitute a stirring pallet when the bucket passes through the embankment, and then a member for retaining the falling material when the material overflows through the opening of the next bucket immediately.

10. Device according to any one of claims 6 to 9, characterized in that the front wall is lined;

inside the bucket of a wall disposed substantially radially with respect to the furnace to allow complete emptying of the bucket before it enters the slope.

11. Device according to any one of the claims

- cations 6 to 10, characterized in that the side walls are located beyond the. rear wall to constitute reinforcements,. as well as lateral retention of the falling material received on the, <EMI ID = 88.1> <EMI ID = 89.1>