DE2340062A1 - Process for the agglomeration of dust-like starting materials in a fluidized bed, in particular for the production of cement clinkers - Google Patents

Description

YEB cement plant construction. Dessau.
45 D essa α

Process for agglomerating powdery starting materials in a fluidized bed, in particular special for the production of cement clinkers

The invention "relates to a method of agglomeration of powdery raw materials in a fluidized bed under the action of molten ones Components and for the simultaneous chemical conversion of these starting materials, in particular for the production of cement clinker from powdery raw materials

It is known that fine-grained starting materials can be used in a fluidized bed using the effect of molten components can agglomerate and thereby chemically react by forms a fluidized bed of essentially finished final product, which keeps it at temperatures which are above the melting point of the substances contained in the end product and above that for the intended ones chemical reactions necessary, and in this fluidized bed continuously to such an extent the powdery starting material gives that they consistently consist essentially of the finished end product remain.

The particles in this fluidized bed must be much larger than those of the starting material} if possible so great that at the gas velocities necessary to reach the fluidized bed state, Particles of the size of the starting material towards

** would have to be blown out completely for a long time.

cd The starting material fed into the fluidized bed

_ * agglomerates and reacts simultaneously, being both

• ^ grows like a shell on the particles of the fluidized bed ° as well as itself. Of the part that only increases ro itself, there are already enough left large particles in the fluidized bed

Most of the rest is blown out again as fly dust and after separation in a cyclone added to the feed material again. In the scope of the bulk supply. through shell-like grown raw material and through sufficiently coarse lights .des The finished product is withdrawn from the fluidized bed on top of the product.

Bs has been found that it is necessary for maintaining the fluidized bed state for a long time _t as continuously as possible continuously supplied to the fluidized particles of a size that can not be blown out just from this. This is done by separating the withdrawn product into two grain classes either immediately or after additional grinding and returning the finer product to the process. The portion of this recycled material makes up $ 20 to $ 50 of the product.

The necessity of returning something that is not inconsiderable Proportion of the product is a major disadvantage of the process. He does in bigger things Extensive special equipment required for classification and return transport of the goods. That is one reason for the fact that so far the application of this method and the use of the other gate pulls from Y / Irbelschichtverfahren in applications of the type described, in particular for the production of Clinker for mass cement has not been used or has remained limited to special cases and beyond the research scale has not come out yet

The disadvantageous behavior is due to the fact that in the present arrangement the self-coarsening of the feed material that is just stable in the fluidized bed particles. little concentrated accrue to the originally existing epidemics caused by shell-like growth and at the same time through mutual sintering together.

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gross to be able to displace before they have reached a size at which the fluidized bed succumbs got to. It also comes about because the. smaller ones, just resistant to the fluidized bed particles that are inevitably carried out continuously with the present arrangement, mostly have not yet been sufficiently chemically converted.

The purpose of the invention is to return part of the product via an external material cycle avoid and thereby the necessary facilities for repatriation and the additional To save elimination.

The invention is based on the object of a method for agglomerating dust-like starting materials in the fluidized bed under the action of molten components and for chemical conversion to create these raw materials, with the return of part of the product via an external one Material cycle is avoided.

According to the invention this is achieved in that the fluidized bed reactor in at least two zones, one The fluidized bed zone adjacent to the finished product outlet and a fluidized bed zone opposite the product outlet were operated who work under different operating conditions and who have different tasks. this is either by attaching at least one for the flow of pesticides in the direction of production— discharge of surmountable weirs between the fluidized bed zones supported or alone by applying an elongated Fluidized bed with solids transport in Reached longitudinal direction. In the first 3? All the conditions between the zones suddenly change, in the second? all gradually over a longer section of the fluidized bed

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The fluidized bed adjacent to the Prodaktaastrag— zone is essentially the ataab-like, as yet unchanged source material in one or more Provided to the opposite of the Prodaktauatrag essentially fly dust from our own process. The dusty, still unchanged source material grows in the area adjacent to the product discharge 'Fluidized bed zone preferably in the manner of a halo on the fluidized bed particles and coarsened in subordinate Embrace yourself, what is conditioned by the nature of this substance as well as by the specific Aufgabeleistang - in the sense used here, the ratio of the amount given per unit of time of the raw material to the amount of fluidized bed - and above all the fluidized bed temperature is particularly promoted will. The shell-like growth is controlled via the specific feed rate in such a way that that the particles remain sufficiently chemically converted and the self-coarsening only in one such extents are made that hardly any new ones are satisfactory chemically converted particles from the feed material can remain in the fluidized bed and that Material which has not grown in a sohale-like manner can be blown out of the fluidized bed again almost to the full extent can i) it becomes flue dust that is created and is slightly coarser than the unchanged starting material separated in a suitable known type of dust separator from the gas stream and the product discharge fed to the opposite fluidized bed zone

The pre-agglomerated airborne dust wakes up in the dem duct discharge on the opposite fluidized bed zone, too, and coarsens itself » whereby - due to the properties of the input material - the self-coarsening of the output material in the Increased scope takes place · It is mainly about the specific task performance - in this case the amount of airborne dust released per unit of time -

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"based on the amount of fluidized bed - and the The temperature of the vortex zone is controlled in such a way that the self-coarsening of the feed material formed particles that are just stable in the fluidized bed are still sufficiently concentrated, in order to be able to displace the particles originally present in the fluidized bed before they pass through the shell-like growths and have become so large by sintering together that the fluidized bed he is lying. The requirement that the fluidized bed material already has the chemical composition of the end product must have, is no longer asked here. Still despite this enlargement Insufficiently large particles of the feed material become like fluidized bed zone from / from the product discharge blown out and transferred to the airborne dust, the latter is released together with the airborne dust separated from the fluidized bed zone adjacent to the product discharge in the dust separator already mentioned and returned to the fluidized bed zone opposite the product discharge. Here comes it leads to the creation of a dust cycle via the dust separator and the one opposite to the product discharge Fluidized bed zone.

The bed material displaced from the fluidized bed zone opposite the product discharge is over the weir is transferred into the fluidized bed zone adjacent to the product discharge. Bs is used there to together with the material remaining in this fluidized bed zone from the abandoned dust, the original to displace the existing particles before they grow through the shell-like growth and through the Lower ones sinter into one another. have grown up that the fluidized bed succumbs.

From the fluidized bed zone opposite the product discharge coking, not yet fully reacted particles see here still to the required extent around. .

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It is beneficial in addition to the "previously described." Proceeding a part of the starting material so high above the fluidized bed in the S; brom of the withdrawing To give up exhaust gases so that this predominantly turns into a cloud of fly dust, so first over-the-way Dust separator goes before it gets into the fluidized bed. This procedure has the advantage that during the heating up of the goods that have been given up in this way - especially when the goods that consume heat run off Processes - heat is bound, which leads to a lowering of the exhaust gas temperature, the latter enables a Reduction of the heat expenditure s of the process and reduces the risk of deposits on the furnace lid in which Gas exhaust line and in the dust separator.

In addition, the zone opposite to the discharge can be fed with an additional feed that is still unchanged Make output material to varying degrees, which serves to improve the heat balance of this zone, d. H· to influence their temperature.

It is also possible to use a part of the zone opposite the product discharge and the Branch off the dust separator in the circulation of flowing dust and give it up in the zone adjacent to the discharge. This serves to increase the level of the dust cycle and the supply of small particles to the discharge opposite zone to a permissible level. restrict. This is achieved by the fact that in this zone there is predominantly a shell-like Y axis, that the formation of independent particles is suppressed. However, it requires in the interests of Product quality a task as far as possible from the product discharge removed and means the creation of an additional central zone, which if necessary by a additional for the flow of solids in the direction Product discharge permeable weir can be separated more sharply.

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In the case of little tendency towards self-coarse For substances, it is necessary to have further Weiire in the direction of the product discharge in the product discharge insert adjacent zone. They help through. Increasing the step effect the few in the Effective use of the new particles retained in the fluidized bed.

The choice of process parameters depends on the off the substances. The individual zones or, in addition, the levels of a zone, can either operated with the same or unequal temperature, acted upon by the same or unequal amount of vortex, equal or unequal amount of feed material (unchanged starting material as well as cycle airborne dust). In general, the temperature and the quantity of Tirbelgas are left in the direction of Product discharge gradually increase and the admission of feed material gradually decreases.

The particular advantages of the invention are that it becomes possible to agglomerate in the fluidized bed of fine-grained goods taking advantage of molten components, thereby to allow chemical reactions to take place simultaneously without the need for an external product cycle to work. The intermediate classification or additional partial size reduction required up to now of the product and the special mechanical devices for return transport can be omitted. The invention will be explained in more detail below. In the accompanying drawing show:

Fig. 1i The basic embodiment of the two-zone operated agglomeration and reaction fluidized bed reactor

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Fig. 2: The embodiment with over-

stored loading of the. end up against the product Zone with unchanged output material and the den- product discharge adjacent zone with cycle dust (transition to the three-zone reactor)

Pig. 3: The execution form with multi-stage Execution of the zone adjacent to your product discharge

After the uniform (Pig. 1) the ataub-shaped starting material arrives from a raw material storage or preheating container 1 through a conveying line 2 to a distributor 3. The latter contains two zones of a " layer", the fluidized bed zone opposite the product discharge 6 and the fluidized bed zone 7 adjacent to the product discharge. The two fluidized bed zones 7 and 8 consist of particles that are significantly larger than the output In the example, hot exhaust gas flows through them, since the combustion of fuel drawn from a fuel storage container 9 'through the main line 10, distribution lines 11 and burner lines 12 results in fuel with air in it. The air is brought in via a fan 13, Luftzufuhrongsleitaiag-eii 14, an air preheater 15, an air distribution chamber 16 through a grate 17 as a support for both ".

That from the task itL-chasing 4 | 4 ^f onnittelbar above the ϊ / ircelschiohtoberfläche 13 exiting Ausgan ^ sgut vsesentlichen enters only into the product discharge 6 applied rvirbelsciiichtzcne 7 »3s remains

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BATH ORIGINAL

-Century-

there partly in the agglomerated state and is partly blown out of it again. The blown out The fraction leaves the fluidized bed reactor pre-agglomerated as fly ash via a gas discharge line 19 5, reaches a dust separator 20 and is separated again from the exhaust gas flow. The exhaust gas, which has largely been freed of airborne dust, leaves the dust separator 20 through the exhaust pipe 21, whereby it is used to preheat the starting material before it goes outside

The separated plug dust arrives via the return line 22 in the opposite of the product discharge 6 Fluidized bed zone 8, which is either located solely from the product discharge 6 or in addition through a "weir 23" from the other fluidized bed ζ one 7 can be sharply separated. The fluidized bed zone opposite your product discharge 6 also takes up part of the abandoned fly ash in the agglomerated state. The one not recorded but still further agglomerated fraction also leaves the fluidized bed reactor as fly dust. gate 5 via the gas discharge line 19 »arrives in the dust separator 20 for settling and via the return line back into the one opposite the product discharge 6 Fluidized bed zone 8 back. As a result of giving up the separated fly ash, the partial remaining in the fluidized bed zone 8 and the partial When blown down, an airborne dust cycle is formed Via the fluidized bed zone 8 opposite the product discharge 6, the gas discharge line 19 and the Dust separator 20 out.

The fluidized bed zone 8, which is located opposite the product discharge 6, is sufficiently coarsened Airborne dust displaces the fluidized bed material originally present in it into the next one, the one Product discharge 6 adjacent fluidized bed zone 7 »before

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this has become too large in grain.

the aas of the product discharge 6 opposite Fluidized layer zone 8 displaced fluidized bed material further - together with the starting material taken up by the following Yfirbelschichtzone 7 - aueji in this the originally existing fluidized bed material before it becomes larger in grain than it is selected medium volume allows. The displaced fluidized bed material leaves the product outlet 6 Tiirbelschichtreaktor 5 Taid is used to preheat the Combustion air is used in the air preheater 15.

With the particularly favorable form of outflow, which reduces the risk of deposits and the amount of heat required one gives part of the feed material from the storage or preheating container 1 via the conveying line 2 to the Distributor 3 and additional feed lines 24-i 24 * wide over the 'vortex layer surface 18 on. 3s is so from Exhaust gas flow recorded and resolved to form a cloud of airborne dust. By heating up and binding heat - especially of the processes of heat-binding reactions - the temperature of the exhaust gases and thus that of the ceiling is lowered 25 of the fluidized bed reactor 5 »the walls of the gas exhaust line 19 and the dust collector 20.

According to the further embodiment (Fig. 2), which can be coupled with the basic embodiment, the feeding of flue dust into the 7 / fluidized bed zone 8 opposite the product discharge becomes a feeding of unchanged starting material in varying amounts from the raw material storage or preheating container 1, via the Conveying line 2, the distributor 3 and a first lifting feed line 26 superimposed and thus intervening in a regulating manner on the heat balance, ie on the fluidized bed temperature.

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In addition, it is possible to change the extent from the air-layer zone lying opposite the product discharge 6 8, the gas supply line 19, the dust collector 20 and the return line 22, branched off part of the flight stick circuit and over a second level feed line 27 can be fed to a further middle zone 26, which leads to the product discharge 6 opposite ii / irbel layer ζ one 7 through weirs 23; 2S can be separated more sharply can. The central zone 28 is here simultaneously with unchanged starting material via the feed line 30 applied. By choosing the conditions (feed rate and temperature in the middle zone) based on the preferred Schalenviachstuais one too high finger dust cycle and an impermissible Prevents a reduction in the grain diameter of the material from being vibrated.

Ormen According to a further Ausführungsfora (Fig. 3), the Ausführungsf described with the "far may be coupled to" be in the accompanying the product discharge fluidized bed zone 7 weirs 31 *} 31 inserted * *. 3s is thus a subdivision into individual stages 7 ¹ J . 7 ^lf $ 7 ^llf achieved Each stage is the output product from the Rohstoffvorrats- or Vorwärmbe- holder 1 via the Förderleitung2, the manifold 3 and the Pörderleitungen 4 ^tf j 4 ^fl * |. 4 ^lfli applied All fly ash rely on the gas exhaust line 19 the fluidized bed reactor 5 and pass via the dust separator 20 via the return line 22 into the fluidized bed zone 8 opposite the product discharge 6.

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Claims (4)

Claims; - ^ .) Process for agglomeration of powdery starting materials in a fluidized bed, in particular for the production of cement clinker, the particles of which are significantly larger than those of the starting material, taking advantage of the action of molten components and to carry out of chemical reactions, thereby characterized in that the fluidized bed reactor has at least two zones with different tasks and has operating conditions, a fluidized bed zone (7) adjacent to the product discharge (6) for production predominantly high-quality product and one opposite to the product discharge (6) Fluidized bed zone (8) for predominantly subsequent delivery of particles consumed in the course of agglomeration, these zones being either through a weir (23) that can be overcome for the transport of solids or solely through the different treatment the fluidized bed over the length of an elongated fluidized bed reactor are formed that the The fluidized bed zone (7) adjacent to the product discharge (6) is essentially the dusty, still unchanged Starting material is supplied to such an extent that the fluidized bed is constantly from sufficient chemically converted, the finished product corresponding material remains that the resulting fly dust is separated from the gas flow in a dust separator (20) and reused is that the product discharge (6) opposite fluidized bed zone (8) predominantly from the the fluidized bed zone (7) adjacent to the product discharge (6) is supplied and the in their self-generated flue dust is returned to the same dust separator (20) after separation becomes, whereby this is done to such an extent '- 2 - 409816/0723 in which sufficiently small particles emerge that are not necessarily already complete be chemically converted mass that with the help of the new. particles formed continuously initially originally in the one opposite to the product discharge (6) Fluidized bed zone (8) existing material in the product discharge (6) adjacent Fluidized bed zone (7) is displaced before it is due to its size can lead to a standstill of the fluidized bed, and that this displaced material then the in the fluidized bed adjacent to the product discharge (6) zone (7) originally existing good also displaced, while at the same time still required chemical Conversions take place that lead to the end product, which the reactor through the product discharge (6) leaves. 2. The method according to claim 1, characterized in that that in addition a part of the unchanged starting material through additional feed lines (24 | 24 ') in such Height above the fluidized bed is abandoned, that it dissolves to the plug dust cloud and after separation from the gas flow in the dust separator (20) in the fluidized bed zone opposite the product discharge (6) (8) arrives. 3. Method according to claims 1 and 2, characterized in that, alone or in addition, part of the unchanged starting material is fed into the zone (8) opposite the product discharge (6). 4. The method according to claim 1 to 3, characterized in that alone or in addition from the 3? Lug dust cycle part of the goods is diverted and, together with unchanged original goods, a special one Central zone (28) is fed and that the resulting fly ash with that from the fluidized bed zones (7} 8), which oppose or abut the product discharge (6), is combined. 409816/0723 23AÜÜ62 Method according to claims 1 "to 5, characterized in that alone or in addition the fluidized bed zone (7) adjacent to the product discharge (6) is divided into several stages (7 ¹ I 7 ¹¹ I 7 ^lfl ) ^{by means (31 1} J 31 ^lf) which are all charged with unchanged starting material, the resulting plug dust being combined, separated and allocated to the eddy chi ent ζ one (0) opposite the product discharge (6). 409816/0723