BG111368A - Device for producing clinker from raw flour containing a pre-heater with restricted height - Google Patents

Abstract

The invention relates to a device (1) for producing clinker, which starts with raw flour. The device comprises a rotary kiln (10), a pre-calcinator (12) and a suspension pre-heater, adapted to heat the raw flour by heat exchange with combustion fuel gases, generated in the rotary kiln (10). The pre-heater mentioned above comprises a pair of cyclone separators (30, 40), connected by feeding and heating pipe (42), which contains at least one charging section (42’) of the raw flour. The pre-heater also contains an electrofilter (450) connected to one of the two separators and containing a section of outgoing raw flour, connected to the charging section (42’). Both the separators (30, 40) are arranged of the same height, defining a first horizontal relative plane (101). Furthermore, the pipe (42) is constructed partly above the said first plane (101) and partially below the same plane in order to define a point of maximum height (71) and a point of minimum height (72), respectively of the same pipe. In addition, the charging section (42’) of the raw flour is arranged below the first plane (101).

Description

DEVICE FOR PRODUCING CLINKER FROM RAW FLOUR

CONTAINING HEIGHT LIMITED HEAT LIMITED

DESCRIPTION

FIELD OF THE INVENTION

The present invention is in the field of the manufacture of installations for the production of hydraulic binders. More specifically, the present invention relates to a device for producing clinker starting with raw flour and comprising a suspension preheater of limited height, which means reduced environmental impact.

BACKGROUND OF THE INVENTION

As is known, cement is a hydraulic binder used to bond solid aggregates, such as sand and gravel, to form concrete and mortars, which means the main components for building construction.

On an industrial scale, cement is obtained by mixing and grinding clinker and gypsum, possibly with adjuvants such as limestone, slag and Pozzolan. Currently, clinker is usually produced by a technology called the dry method, which is a high-temperature firing product of a mixture of raw materials consisting mainly of limestone (calcium carbonate) and clay (silica, alumina, iron oxides, except crystallization). water). The raw materials are mixed in a solid state in the desired proportions and then finely ground to obtain a homogeneous powder called raw flour (or raw mixture). Therefore, for the objects of the present invention, the term raw flour or raw mixture is to be understood as a homogeneous powder used as a starting material for the production of clinker. The raw flour, after being pulverized and dried in a special mill, is metered into a preheater / calciner and subsequently transformed into clinker by baking at a temperature of about 1450 ° C in a rotary kiln consisting mainly of an inclined rotating cylinder. During the heat treatment in the rotary kiln, the raw flour reacts to form silicates and calcium aluminates (clinkerization reaction), which are the main components of clinker.

In prior art clinker production plants, the raw flour is subjected to preheating and, if necessary, pre-treatment for calcination before being fed to the rotary kiln. Currently, one of the most commonly used preheating techniques is based on the use of a so-called suspension preheater or cyclone multistage preheater (hereinafter referred to simply as a preheater), consisting of a cyclone tower in which each preheater preheating stage is performed in one or more cyclone separators. At each preheating step, the raw flour is first dispersed in a vertical gas stream tube and then separated by centrifugal force into a large diameter cyclone separator (8-9 meters). This vertical tube essentially constitutes a preheating step of the preheater

Figure 1 is a schematic view with respect to a multi-stage preheater known in the art. In fact, this preheater is similar to a countercurrent heat exchanger, in which the raw flour is heated by gravity drip from top to bottom, while the hot gases,

-Ίproduced in the rotary kiln move back to the top of the preheater. The preheater shown schematically in Figure 1 comprises four preheating steps. However, the number of these steps may vary depending on the applications

For example, the preheater illustrated in Figure 1 comprises a first preheating step, typically defined at the inlet by a pair of first cyclone separators 301 powered by a first supply section (denoted by the figure 401). The latter is crossed by the exhaust fumes from the second cyclone separator 302 in the second stage of the preheater. The raw flour is introduced into the first tube 401 so that it is simply mixed with the fumes entering from the second separator 302. This first tube 401 is typically divided into two branches, each directed to the inlet of one of the first cyclones of the first stage of the preheater. These first separators 301 then perform a first separation between the preheated raw flour and the smoke. In particular, each of the first separators 301 comprises an outlet section for the raw flour and an outlet section for the smoke. In particular, the effluents from the first separators 301 are then used in the raw flour grinding / drying plant before being released into the atmosphere as dusting.

The raw flour leaving the first separators 301 is introduced into a second tube 402, which connects the outlet of a third separator 303 to the supply of the second separator 302, located at a higher height. The outgoing raw flour from the latter is subsequently introduced by gravity into a third pipe 403, which connects a fourth separator 304 with the third separator 303, which is located at an intermediate height between the second separator 302 and the fourth separator 304. The outgoing raw flour from the third separator 303 enters a fourth tube 404, which connects the fourth separator 304 to the outlet of the rotary kiln 500 to be subsequently fed back to the fourth separator 304. In the latter, the raw flour is finally separated from the smoke and discharged into the rotary kiln. 500 to be transformed into clinker.

The number of preheating steps is determined by the humidity of the raw materials to be dried in the grinding / drying plant that actually uses these gases, and therefore the amount of heat energy associated with them, after which they leave the preheater. In particular, in the presence of high humidity of the raw materials, a higher amount of heat for drying is actually required and, therefore, only four stage preheaters will be used. However, in the presence of medium humidity, five stage preheaters are used, while in the presence of raw materials with low humidity, six stage preheaters are used.

The choice of raw materials with low moisture content and the precise design of the vertical pipes and cyclones, which form the different stages of heating, result in the fact that it is now common to make five or even six stage preheaters with sufficiently long connecting vertical pipes. to increase the contact time and therefore the heat exchange between the gas and the material, and ultimately, the overall thermal efficiency of the process.

In addition, the nominal production capacity of cement kilns in recent years has increased significantly, reaching from 1000-2000 tpd (tons per day) clinker in the seventies, to 5000-7000 tpd typical of the latest projects. This trend has led to an increase in the physical size of tubular preheaters and to a proportional increase in cyclone heights. It follows from all of the above that suspension preheaters, which in the past had heights of 60 to 80 W, now usually exceed 120 m in height

-3 and even reach 140-150 sh.

The significant height of the preheaters causes an important problem of visual impact on the environment, which has not been heard of before, as the heights of the preheaters, much more limited, did not deviate significantly from the higher deposit silos (40 to 60 t). Currently, instead of a preheater, a tower rises above the cement plant, which becomes a characteristic element of the landscape, visible from a great distance. Therefore, in this sense, the growing sensitivity to environmental issues makes it increasingly difficult to obtain the necessary building permits from local authorities.

Therefore, as mentioned above, the height of the preheater is determined primarily by the number of stages of the preheater, which in turn depend inversely on the moisture content of the raw materials. The height of the preheater is also related to the length of the connecting pipes, with the increase of which the thermal efficiency of the preheater increases. Finally, with the increase of the nominal production capacity, (that is, tons of clinker produced per day) increases the size of the preheater and especially its height. In this sense, it should be added that a high daily clinker productivity cannot be considered without the presence of a pre-calciner located between the rotary kiln and the preheater. In the conventional solution, the pre-calciner is structured as a central tower, next to which are arranged several cyclones that form the preheater. The pre-calciner reaches significant heights, in the range of 60 to 70 tons, thus constituting a disadvantage in terms of height, but at the same time, also a necessary structural limitation.

In view of these facts, in order to limit the overall height of the preheaters, so far actions have been taken to reduce the height in relation to the ground and, on the other hand, to reduce the overall vertical dimensions. The first type of operation includes, in particular, all installation solutions which provide for a reduction in the height, in relation to the ground, of the structures along the preheater, and hence of the rotary kiln and the cooler. In particular, these structures are located underground to reduce their emergence in relation to the soil. However, this solution has several drawbacks. First, in order to allow easy maintenance and to increase security levels, it is preferable to have production facilities above ground. For this purpose, therefore, the decision to locate the structures below ground level along the preheater is clearly undesirable. In addition, the construction of structures below ground level requires extensive additional excavations and, when it is desired to reduce the height, beyond a certain limit in relation to the ground, of chiller tapping installations, a limit must be observed in order to be able to pass between the bases of the rotary kiln to allow acceptable movement inside the installation.

An alternative solution is one that provides action on the geometry of the preheater tower to limit its height. In particular, the most common action is to divide the cluster into cyclones, in fact, by building two towers that run in parallel, or as they call it in trade, building a tower with two strings. In this case, on each string that has a capacity equal to half the total capacity, the dimensions of the cyclones and associated tubes decrease, and therefore the overall height is also more limited. However, this solution has a drawback, as it requires construction and maintenance costs almost double compared to the simple string solution (Figure 1), beyond some difficulties

-4of a managerial nature. Specifically, it is not easy to maintain a balance between the two strings in terms of gas flow rate and materials. One solution, alternative to the two-string configuration, could be the design of a Turkish tower with cyclones and shorter connecting pipes, with obvious losses in terms of thermal efficiency, as the reduced development of the connecting pipes damages the gas-material contact. in times and therefore heat transfer.

A partial solution to the problem related to the height of the preheater is given in patent application PCTL2009 / 00782. This application schematically shows the technical solution of Figure 2, wherein the preheater comprises an electrostatic precipitator 450 located substantially on the ground, which is substantially based on the preheater. The electrostatic precipitator 450 is connected to a first cyclone separator 460 by a predominantly vertical tube that defines a section for loading the raw flour. The fumes coming out of the first separator 460 are mixed with the raw flour introduced into the vertical pipe, which reaches the inlet 453 of the electrostatic precipitator 450. Within the latter, the separation is carried out by electrostatic precipitation. The fumes coming out of the electrostatic precipitator 450 are treated by a catalytic smoke treatment system 500 to reduce NOx emissions, while the raw flour is sent upwards to be introduced into a pipe 470 which connects the outlet of a second cyclone separator 465 with the input of the first separator 460.

In connection with the solution of Figure 1, the use of the electrostatic precipitator 450 in the base of the preheater leads to a reduction in the height of the preheater, for an equal number of heating stages, in fact, the level difference (indicated by 501 in Figure 1). required for the positioning of the first separators (indicated by the reference figure 301 in Figure 1) is eliminated. However, it can be seen that this solution alone is not enough to satisfactorily solve the altitude problem, as reducing the permissible level (of the order of about ten meters) is not enough to significantly reduce the environmental impact Wednesday.

On the contrary, it can be seen that the solution shown in Figure 2 actually introduces another problem related to the control of the raw flour from the outlet of the electrostatic precipitator 450. In fact, the grounding of the latter, and essentially the conventional preheater structure , define a significant level difference (denoted by 502) between the output of the raw flour 451 from the electrostatic precipitator 450 and the charging section of the second tube 470 between the first separator 460 and the second separator 465. In order to allow the raw flour to overcome this difference in level 502 requires a rearrangement of the adequate means of operational feeding, which means the management of the raw flour. The required capacity for these feeders depends, on the one hand, on the object of this difference with level 502 and, on the other hand, on the length of the pipe used to transport the raw flour. In fact, as their length increases, the required capacity also increases.

It is obvious, therefore, that with the model of the conventional preheater, with increasing heating stages (which means increasing the number of cyclone separators), the difference at level 502 to be overcome increases directly, as does the required capacity required by the means for operative feeding of the raw flour. It is obvious, therefore, that the use of the electrostatic precipitator 450, although advantageous in terms of height reduction, does not go well with the cluster structure of the conventional preheaters shown in Figures 1 and 2.

Therefore, on the basis of the above considerations, it becomes clear the need for technical solutions alternative to those mentioned above and to the previous ones.

- 5 developments, to limit the size of the height of the preheaters, without limiting the efficiency and production capacity of the same. Therefore, a main object of the object of the present invention is to provide a device for the production of clinker, starting from raw flour, which device allows to overcome the above-mentioned disadvantages. Within this objective, the first objective is to provide a device for the production of clinker which, at the same capacity, has a more limited height relative to the ground compared to conventional solutions. Another object of the present invention is to provide a device for the production of clinker in which the structure of the preheater is optimally combined with the presence of an electrostatic precipitator. Last but not least, the goal is to provide a device that has lightweight reliability and can be easily manufactured at a competitive cost.

SUMMARY OF THE INVENTION

Therefore, the present invention relates to a device for the production of clinker from raw flour. The device consists of a rotary kiln and a pre-calciner that communicates with the rotary kiln to be crossed by the combustion fumes generated in the kiln of the same. The precalciner comprises a section of incoming fumes that defines a substantially horizontal plane on a relative basis. The device according to the invention comprises a suspension preheater, which is above this plane of the relative base, for heating the raw flour by heat exchange with the fuel fumes coming out of the pre-calciner. In particular, this preheater contains:

- a first cyclone separator comprising a section of feed raw flour mixed with fumes, a section of effluent fumes and a section of effluent raw flour;

- at least one separation electrostatic precipitator located below the first separator, this electrostatic precipitator comprising one section of the feed raw flour mixed with the fumes, a section of the exhaust fumes and at least one section of the outgoing raw flour;

- a first supply and heating pipe connecting the supply section of the electrostatic precipitator to the outlet section of the first separator, said first pipe comprising a first section of the outgoing raw flour;

- at least one second cyclone separator comprising one section of feed raw flour mixed with smoke, one section of effluent flue and one section of effluent raw flour;

- a second supply and heating pipe connecting the outlet section of the second separator to the supply section of the first separator, said second pipe comprising a second loading section of said raw flour;

- means for operative supply of the raw flour for control of the raw flour from the outlet section of the electrostatic precipitator to the section of the second charge of the second pipe.

The device according to the invention is characterized in that the first separator and the second preheater separator are arranged at substantially the same height with respect to the plane of the relative base in such a way that the respective sections of the exhaust fumes define a first substantially horizontal relative plane. Furthermore, according to the invention, the second tube has a first part which is constructed below the first plane and a second part which is constructed above the same first plane in order to define, respectively, one point of maximum height and one point of minimum height of the second pipe. Furthermore,

The section of the second charge of the second tube is defined by said first part of the second tube.

The use of two separators located at the same height reduces the total height of the preheater in relation to conventional solutions in which the separators are arranged in a cascade of different heights. It can be seen that the use of a tube constructed on opposite sides with respect to the first relative plane makes it advantageous to limit the magnitude of the level difference between the raw filter outlet section and the filling section defined on the same second tube. . As a result, the required path for moving the raw flour and therefore the required capacity of the means for feeding the raw flour to the same is advantageously reduced.

EXPLANATIONS OF THE ATTACHED FIGURES

Further features and advantages will be disclosed by the following detailed description of the preferred embodiments of the clinker production device according to the present invention, illustrated only by a non-limiting example with the accompanying drawings, wherein:

Figure 1 is a schematic view relating to a first clinker production device starting with raw flour of a known type;

Figure 2 is a schematic view relating to a second clinker production device starting with raw flour of a known type;

Figure 3 is a schematic view of a possible embodiment of a device according to the present invention;

- Figure 4 is an enlarged view of detail IV defined by the dotted line of Figure 3, and - Figure 5 is an enlarged view of detail V defined by the dotted line of Figure 3. In the Figures, the same relative numbers and letters identify the same. same elements or components.

EXAMPLES OF EMBODIMENT OF THE INVENTION.

In connection with the cited Figures, the present invention relates to a device 1 for producing clinker starting with raw flour. The device 1 according to the invention consists of a rotary kiln 10 and a pre-calciner 12 which communicates with the rotary kiln 10 to be passed by the smoke generated in the kiln thereof. Flowwise, the rotary kiln 10 consists of a section 10 'of exhaust fumes communicating with the inlet section 12' of the pre-calciner 12. This inlet section 12 'defines a substantially horizontal plane on a relative base 100, from which the pre-calciner 12 extends vertically. direction. The vertical dimensions of the latter may vary depending on the performance required by the device 1, according to known criteria per se.

The device 1 according to the invention comprises a suspension preheater (hereinafter referred to simply as a preheater) for heating the raw flour intended for the rotary kiln 10 by heat exchange with the fuel fumes generated in the rotary kiln 10 and the outlet of the pre-calciner 12. In particular the preheater is of the suspension type with cyclone separators. From a design point of view, the preheater is designed in the vicinity of the pre-calciner, according to an arrangement criterion known per se. For this purpose, therefore, the embodiments shown in Figures 3 and 4 should be considered to be purely schematic, with the sole purpose of showing the mutual vertical arrangement of the various separators that make up the preheater.

Figures 3 and 4 refer to a device according to the invention, denoted by the figure 1.

-Ί The preheater of the device 1 consists of a first supply and heating tube 32, in which the raw flour is introduced, preventively treated according to processes, self-curved (for example pulverization and drying in a special mill). In particular, the first tube 32 consists of a first loading section 32 'through which the raw flour is incorporated. The first pipe 32 is crossed by the combustion fumes generated in the rotary kiln 10 and the first stage of heating the raw flour in a mixture with said fumes takes place in it.

The preheater of the device 1 comprises at least one first cyclone separator 30 and a second cyclone separator 40 arranged at the same height with respect to the plane of the relative base 100 mentioned above. These separators 30, 40 have a structure known per se. In particular, each of them has a substantially cylindrical upper part from which a substantially funnel-shaped lower part emerges. For each of the two separators 30, 40, the upper part defines a feed section ZG, 41 'with a mixture of raw flour-smoke. These feed sections 3G, 41 'are defined in such a way as to provide a tangential inlet of this mixture into the separator.

For each of the separators 30, 40, the upper part also defines a section of the exhaust fumes 31, 41, which allows a substantially vertical outlet of the fumes from the separator of the same. Finally, for each of the two separators 30, 40, the lower funnel-shaped part defines, near the most beveled part, a section of the outgoing raw flour ZG, 4G (hereinafter referred to as the section for the exit of the raw flour ZG, 4D).

The preheater also contains a separation electrostatic precipitator 450 for raw flour fumes. This electrostatic precipitator 450 is located at least below the first separator 30. The electrostatic precipitator 450 comprises one feed portion 11 'of the raw flour-smoke mixture, one portion of the effluent fumes 11 and one portion of the raw flour output 1G. The smoke outlet section 11 is connected to a flue pipe 28 at the end of which a suction device 29 is arranged to create sufficient suction conditions so as to ensure a constant flow of smoke through the preheater and the pre-calciner 12.

The above-mentioned first pipe 32 connects the supply section 11 'of the electrostatic precipitator 450 to the outlet section 31 of the first separator 30. The second supply and heating pipe 42 instead connects the outlet section of the second separator 40 to the supply section 3 of the the first separator 30. This second tube 42 defines a second heating step for the raw flour and comprises a second loading section 42 ', through which the raw flour from the outlet of the electrostatic precipitator 450 is inserted into the same second tube 42. a heater is provided with raw flour feed means (described below) for controlling the raw flour outlet from the electrostatic precipitator portion 1D 450 to the second outlet section 42 'of the second tube.

According to the present invention, the first separator 30 and the second separator 40 are arranged at the same height with respect to the surface of the relative base 100 mentioned above. It is thus intended to indicate a state in which the outlet section 31 of the first separator 30 and the outlet section 41 of the second separator 40 are located at substantially the same height H with respect to the base surface 100. defining from it a substantially horizontal first relative plane 101. According to the present invention, the second tube 42 has a first part 33 'which is constructed below the first plane 101 and a second part 33 which is constructed above the same first plane 101. The first part 33 'and the second part 33 actually define the point of the minimum

-8height 72 and the point of maximum height 71 of the second tube 42 with respect to the surface of the relative base 100. Furthermore, according to the present invention the first part 33 'of the second tube 42 defines the above-mentioned second loading section 42' intended to be fed with 450 raw flour coming out of the electro-filter.

The arrangement of the two separators 30, 40 and the structure of the second tube 42 allows a significant reduction in the total height of the preheater with respect to the known solutions in which the cyclone separators are arranged at different heights, as shown in Figures 1 and 2. , it was seen that such solutions have a synergistic effect in terms of limiting the overall height of the preheater. In fact, not only is the typically typical level difference between two adjacent separators reduced (see Figure 1), but the space between the same separators is advantageously used to define a given stage of heating the raw flour. In fact, by this solution the preheater is advantageously sealed downwards, ie to the surface of the base 100. Furthermore, by the special structure of the second tube 42, the height of the second charging section is also advantageously reduced and therefore the work required by the feed means for raising this raw flour.

From a structural point of view, the first separator 30 and the second separator 40 have, in addition to a similar structure, preferably also the same vertical extension measured from the respective section of the outgoing fumes 31, 41 to the corresponding section of the outgoing raw flour 3G, 4D. In particular, the two separators 30, 40 have such a height that the portion of the outgoing raw flour 3 of the first separator 30 and the section of the outgoing raw flour 4D of the second separator 40 are substantially located on a substantially horizontal second relative plane 102 and below said first relative plane 101. For this purpose, according to a preferred embodiment, the first part 33 'of the second tube 42 is constructed in such a way that, as a result, the point of minimum height 72 is below this second plane 102. Furthermore, the second a charging section 42 'is preferably defined below this second plane 102. This solution allows a further reduction in the level difference between the raw flour output section 1D of the electrostatic precipitator 450 and the second charging section 42', which leads to to further reduce the work required to manage the raw flour, and hence to further limit the overall size and capacity of the raw material. erative means for feeding raw flour.

In particular, as seen in Figure 4, the first portion 33 'of the second tube 42 connects to the supply portion 33' of the first separator 30 and has a substantially U-shaped structure constructed entirely below the first plane 101 and in fact, defining the point of minimum height 72 of the second tube 42. The second part 33 of the second tube 42 is instead a U-shaped upside-down structure, this expression being intended to indicate a curved part so as to define a 180 ° curve which is constructed to the first plane 101, which actually defines a point at the maximum height 71 for its pipe.

As shown in Figure 4, the second tube 42 also includes a fitting portion 34, at least partially curved, which is connected to the first branch of the first U-portion 33 'and is also constructed below the first plane 101. In fact, the fitting portion 34 defines the end portion of the second tube 42 connected to the first separator 30. Finally, the second tube 42 comprises a central rectilinear portion 35 that connects the second branch of the first U-shaped portion 33 'to the first upside-down branch. second U-shaped part 33. The second branch of the second part 33 is rather connected to the section of the outgoing

-9fumes 41 of the second separator 40.

In the embodiment shown in Figures 3 to 5, a first vertical part (indicated under number 37 in Figure 4) of the first part 33 'of the second tube 42 defines the second section of the raw flour 42'. This solution makes it possible, in fact, to avoid, or at least to reduce, possible deposits of raw flour at the point of minimum height 72 defined by the U-shaped structure of the first part 33 '. For this purpose, according to a preferred embodiment of the invention not illustrated herein, the second tube 42 comprises means for evacuating the raw flour located near this point at a minimum height of 72 in order to remove any remnants of raw flour which may accumulate in correspondence with this point.

In the embodiment illustrated in Figures 3 to 5, the preheater of the device 1 comprises a third cyclone separator 50 with a structure substantially equivalent to that of the first separator 30 and the second separator 40. In particular, the third separator 50 comprises a feed section. 5D, a section of outgoing smoke 51 and a section of outgoing raw flour 5D (shown in Figure 4). The third separator 50 is located below the first relative plane 101 and so that the portion of the exhaust fumes 51 is located on a third relative plane 103 below the first plane 101 and on the second relative plane 102.

The outlet section 51 of the third separator 50 is connected to the supply section 41 'of the second separator 40 via a third pipe 52, which has a structure known per se. which comprises a substantially vertical rectilinear portion, an outlet portion of the outlet section 51 of the third separator 50, and a curved portion that connects the rectilinear portion to the supply portion 41 'of the second separator 40. This third tube 52 essentially defines a third stage of heating the raw flour, which is introduced through a third loading section 52 '. The latter is connected to the outgoing raw flour section 3 of the first separator 30 by a first raw flour supply pipe 39 'structured so that said raw flour gravitationally reaches this third loading section 52.

The preheater according to the invention further comprises a fourth cyclone separator 60 in a shape substantially corresponding to that of the third separator 50. Again, with reference to Figures 3 and 4, it can be seen that the fourth separator 60 comprises a feed section 6D connected to the outlet of the pre-calciner 12 and a section of the exhaust fumes 61 connected to the supply section 51 'of the fourth separator 50 by a fourth supply and heating pipe 62, which in fact defines a fourth stage "of heating the raw flour". For this purpose, it is found that the fourth tube 62 comprises a fourth raw flour loading section 62 'connected to the raw flour output section 4D of the second separator 40 by means of a second raw flour supply tube 39'. This second tube 3 'is also structured so as to allow gravity sliding of the raw flour in the fourth section 62'.

As shown in the Figures, the fourth separator 60 is located below the first relative plane 101. In particular, the portion of the exhaust fumes 61 of the fourth separator 60 lies on the third plane 103 identified by the portion of the exhaust fumes 51 of the third separator 50. In other words, the third separator 50 and the fourth separator 60 are at the same height H2 with respect to the surface of the relative base 100 mentioned above, which constructs the preheater.

In particular, as can be seen from Figure 4, the fourth tube 62 preferably comprises a first, substantially upside down, U-shaped portion 64 'and a second fitting portion 64, which connects the first portion 64' to the supply portion 5. D of the fourth

- 10separator 50. The upturned U-shaped expression denotes the curved part so as to define a curve of about 180 degrees, which is constructed to the third plane 103, defining a point at maximum height 66 for its fourth tube 62 .

As noted above, the feed portion 61 'of the fourth separator 60 is connected to the outlet portion 12 of the precalciner 12 through a fifth feed and heating tube 72, which defines a fifth step of heating the raw flour. This fifth tube 72 is intersected by the combustion fumes generated by the rotary kiln 10, wherein the raw flour is introduced through the charging section 12 'of the pre-calciner 12 (as shown in Figure 3). The latter is connected to the section of the outgoing raw flour 51 'of the third separator 50 by a third supply pipe 39, which allows gravity sliding of the raw flour on it. The fourth separator 60 comprises a portion of the raw flour outlet 6G connected to the inlet portion 10 'of the rotary kiln 10 through a fourth raw flour feed pipe 39'.

The fifth tube 72 is constructed partially above and partially below a fourth, substantially horizontal relative plane 104, defined by the portion of the exhaust fumes 12 of the precalciner 12. More specifically, the fifth tube 72 comprises a first end portion 82 'having a U- image structure with the head turned down. The first portion of this first portion 82 'is connected to the outlet portion 12 ”of the precalciner 12, while the second portion is bent relative to the first to define a curve of about 180 degrees, which is constructed to the fourth plane 104, defining thus a point of maximum height 82 for the fifth tube 62. The latter also comprises a second rectilinear portion 82 which is constructed from a second portion of the first portion 82 'to a height near the third plane 103. Finally, the fifth tube 72 comprising a fitting portion 82 'that connects the second rectilinear portion 82 to the supply portion 61' of the fourth separator 60. The third connecting portion 82 'is substantially shaped as a curve to constitute a minimally elongated portion, i.e., for to connect the second part 82 to the supply portion 61 'of the fourth separator 60 in a minimal structural space.

Turning again to Figure 5, it can be seen that the first pipe 32 comprises a first U-shaped U-shaped first part 23 'so that a first section connects to the outlet section 31' of the first separator 30, and a second part of the same first part 23 'is curved with respect to the first part to define a curve of about 180 degrees, which is constructed towards the first plane 101 to define a point at the maximum height 92 of the first pipe 32. The latter also comprises a second rectilinear part 23, which is constructed from the second part of the first part 23 'to a height close to that of the supply section 11' of the electrostatic precipitator 450.

The second rectilinear portion 23 defines the first loading section 32 ', through which the raw flour is introduced for mixing with the incoming fumes from the second separator 30. In particular, this first loading section 32' is defined at a height close to that of the first plane 101. to increase the path length of the flue flour mixture inside the first tube 32, in order to increase the heating efficiency of the raw flour at the expense of the fumes.

With reference to Figures 3 to 5, as indicated above, the preheater of the device 1 according to the invention comprises operative means for supplying raw flour for controlling the raw flour from the outlet of the electrostatic precipitator 450 to the second charging section. 42 'of the second pipe 42, which connects the supply section 31' of the first separator 30 with the section of the exhaust fumes 41 of the second separator 40. These operating means include at least one supply pipe 70, which connects

- 11 the operating sections of the raw flour output 1D of the electrostatic precipitator 450 with the second filling section 42 'of the second tube 42. The feed means also comprise a drive device 77 adapted to give the raw flour sufficient traction to to overcome the difference in the level of the outgoing portions of the raw flour 1D of the electrostatic precipitator and the charging section 42 'of the second tube 42. This actuator 77 may be, for example, a pneumatic type, or one which moves the raw flour upwards by means of air / gas. Alternative embodiments, but functionally equivalent to the drive device 77 and to the raw flour feed means in general, should in any case be considered within the scope of the present invention.

In order to further limit the amount of work required for these operating means, the second tube of raw flour 42 can be structured so as to further reduce the point of minimum height 72, or, therefore, to reduce the position of the second raw flour loading section 42 '. For this purpose, a dotted line figure 5 shows an alternative embodiment in which the point of minimum height 72 of the second pipe 32 is located below the third plane 103 defined by the position of the third separator 50 and the fourth separator 60.

Also, preferably, the charging section 42 'is below the third relative plane 103. As can be seen from Figure 5, this solution allows a strong reduction in the difference in the H3 level between the fifth relative plane 105 and the sixth relative plane 106, respectively, a line for the position of the sections of the outgoing raw flour 1D of the electrostatic precipitator 450 and for the position of the second section for loading the raw flour 42 '. As already mentioned above, the lowering of the position of the second charging section 42 ', due to the special structure of the second tube 42, results in a advantageous reduction in the required capacity of the drive device 77, or a reduction in the overall dimensions and costs. for the operational means feeding the raw flour.

Referring once more to Figure 3, it can be seen that the point of maximum height 91 of the first pipe 32, the point of maximum height 71 of the second pipe 42 and the point of maximum height 81 of the fifth pipe 72 are essentially of the same height H1 with respect to the plane of the relative base 100. In other words, according to this solution, a plane of maximum height 107 is established for the preheater.

For the sake of completeness, the principle of operation of the preheater of the device 1 shown in Figures 3, 4 and 5 is described below. In particular, the figures with a continuous line show the movement of the fuel fumes in the preheater while with a dashed / dotted line, the movement of the raw flour is shown. The raw flour is introduced through the first section 32 'into the first pipe 32 in a conventional manner and is mixed with the smoke coming out of the first separator 30. As it crosses the first pipe 32 lengthwise, the raw flour undergoes first heating with a first smoke heat exchange effect. At the end of the first pipe 32, the smoke-raw flour mixture reaches the electrostatic precipitator 450, in which the raw flour is separated from the smoke by precipitation. The latter are led to the discharge pipe 28 of the suction device 29.

The raw flour leaving the electrostatic precipitator 450 is moved by the operating means 70, 77 to the second charging section 42 'of the second pipe 32. Within the scope of the latter, the raw flour is mixed with the incoming fumes from the second separator 40, subjected to a second heating by the action of a second heat exchange with the same fumes. Once, the mixture of raw flour-smoke reached, through the second pipe 42, the second separator 40, in which the raw flour is separated for the second time from

- 12 smoke. The latter once again cross the length of the first pipe 32, and the raw flour reaches the third section 52 'of the third pipe 52, which connects the section of the outlet flue 51 of the third separator 50 with the supply section 41' of the second separator 40. By mixing with the flue leaving the third separator 50, the raw flour undergoes a third heating to be separated again from the same fumes in the second separator 40.

Through the second feed pipe 39 ', the raw flour reaches the fourth pipe 62, which connects the outlet section 61 of the fourth separator 60 with the supply section 51' of the third separator 50. The raw flour here again mixes with the fumes in the position of the proximal exit section. flue 61 of the fourth separator 60 to cross the fourth tube 62 over almost its entire structure, thus subjecting it to a fourth heating, which essentially ends after reaching the third separator 50. In the latter, the raw flour is separated from the flue. to be subsequently transported, through the third supply pipe 39, to the pre-calciner 12 to generate another mixture at the high temperature of the smoke entering directly from the rotary kiln 10.

The raw flour mixed with these fumes rises vertically in the pre-calciner 12 along its entire height and then crosses the fifth pipe 72 to the fourth separator 60, where it undergoes the last separation step. During the passage into the pre-calciner 12 and the fifth tube 72, the raw flour undergoes a sixth heating step. The raw sludge from the outlet of the fifth separator 60 finally reaches the feed section of the rotary kiln 10, in which the process of calcination of the raw flour is completed.

The clinker device conceived in this way is susceptible to certain modifications and variations, all falling within the scope of the inventive concept. In addition, all parts may be replaced by other technical equivalents. In practice, the materials and sizes used and the contingent of shapes can be any, according to the requirements and state of the art.

Claims (13)

PATENT CLAIMS A device (1) for producing clinker starting with raw flour, said device (1) comprising a rotary kiln (10) and a pre-calciner (12) communicating with said rotary kiln (10) so as to be crossed of the combustion fumes generated in said rotating object (10), said pre-calciner (12) comprises a section of incoming flue (12 ') which defines a substantially horizontal plane on a relative base (100), said device (1) comprising a suspension preheater adapted to heat said raw flour by heat exchange with said combustion fumes emanating from said precalciner (12), said preheater comprising: - a first cyclone separator (30) comprising a feed section (31 '), a smoke outlet section (31 ") and a raw flour outlet section (31"'), - at least one electrostatic precipitator (450) for separating said crude flour from said fumes located below said first separator (30), said electrostatic precipitator (450) comprising a supply section (1D), a section of outgoing smoke ( And ”) and at least one first outgoing portion of the raw flour (11” '); - a first supply and heating pipe (32) which connects said supply section (1D) of said electrostatic precipitator (450) to said outlet section of smoke (31 ") of said first separator (30), said first pipe (32) , comprising a first raw flour loading section (32 '); - at least one second cyclone separator (40) comprising a feed section (4G), a smoke outlet section (41 ”) and a raw flour outlet section (4G”), - a second supply and heating pipe (42) which connects said section of the outlet smoke (41 ”) of said separator (40) with said supply section (3G) of said first separator (30), said second pipe (42) a second loading section (42 ') of said raw flour; - means for operatively feeding the raw flour to move said raw flour from said at least one outlet section (11 '") of said electrostatic precipitator (450) to said second loading section (42') of said second tube ( 42), characterized in that said first separator (30) and said second separator (40) are arranged at substantially the same height with respect to said plane of the relative base (100) so that the respective sections of the exhaust smoke (ZG, 41) define a first, substantially horizontal relative plane (101) and is that said second tube (42) has a first part (33 ') which is constructed below said first plane (101) and a second a part (33 ”) which is constructed above said first plane (101) so as to define one point of maximum height (71) and one point of minimum height (72) of said second pipe (42), such as said first part (33 ') of the village of said second tube (42) defines said second charging section (42 '). Device (1) according to claim 1, characterized in that said first separator (30) has a height substantially equivalent to that of said second separator (40) so that the outlet section (3G) of said first separator (30). 30) and the outlet portion (4D ") of said second separator (40) are located on a substantially second horizontal relative plane (102) below said first plane (101), said second part (33 ') of said second tube ( 42) is constructed such that said point at minimum height (72) is below said second plane (102). Device (1) according to claim 2, characterized in that said - 14first part (33 ') of said second tube (42) defines said second charging section (42') below said second plane (102). Device (1) according to any one of claims 1 to 3, characterized in that said first part (33 ') is substantially U-shaped and communicates with said supply section (3G) of said first separator (30) and in said second part (33 ") is substantially U-shaped upside down and communicates on the first side with said first part (33 ') and on the second side with said section of the exhaust smoke (41 ”) of said second separator (40). Device (1) according to claim 4, characterized in that said second pipe (42) comprises at least a partially curved fitting part (34) connected on one side to said supply section (3H) of said first separator. (30) and, on the other hand, with said first substantially U-shaped part (33 '), said second tube (42) comprising a rectilinear central part (35) which connects said first part (33') with said second part (33 ”). Device (1) according to any one of claims 1 to 5, characterized in that said preheater comprises: a third cyclone separator (50) comprising a feed section (51 '), a smoke outlet section (51 ") and a raw flour outlet section (5D"), said third separator (50) being located in such a position that said an outlet portion (51 ”) of said third separator (50) defines a third substantially horizontal relative plane (103) below said first relative plane (101), - a first supply and heating pipe (52) which connects said section of the outlet smoke (51 ") of said third separator (50) with said supply section (4D) of said second separator (40), such as said third pipe (52) comprising a third loading section (52 ') connected to said raw flour outlet section ("ZG") of said first separator (30) by means of a first supply pipe (39). Device (1) according to claim 6, characterized in that said preheater comprises: - a fourth cyclone separator (60) comprising a feed section (6G), a smoke outlet section (61 ”) and a raw flour outlet section (6G”), said fourth separator (60) being located in such a position that said outlet a portion (61 ”) of said fourth separator (60) is located substantially on said third relative plane (103); - a fourth supply and heating pipe (62) which connects said section of the outlet smoke (61 ") of said fourth separator (60) with said supply section (5D) of said third separator (50), said fourth pipe (62) contains a fourth charging portion (62 ') connected to said portion of the raw flour outlet (41' ") of said second separator (40) by means of a second feed pipe (39 '); - a fifth supply and heating tube (72) which connects said supply section (6D) of said fourth separator (60) to said outlet section (12 ”) of said precalciner (12). Device (1) according to claim 6 or 7, characterized in that said fourth supply and heating tube (62) comprises a first U-shaped part with the head downwards (64 '), which is constructed above said third plane ( 103) and a second fitting portion (64 ") that connects said first portion is U-shaped (64 ') to said supply portion (5D) of said third separator (50). Device (1) according to claim 7 or 8, characterized in that - 15 said outlet portion (12 ”) of said precalciner (12) identifies a fourth substantially horizontal relative plane (104) above said third plane (103) and as said fifth tube (72) comprises: - a first end portion (82 ') connected to said outlet portion (12 ") of said precalcinator (12), said first portion (82') being constructed above said fourth plane (104) in accordance with a substantially U- image structure upside down; - a rectilinear central part (82 ”) which is constructed vertically from said first part (62) to a height close to that of said third plane (103); - a second end portion (82 '") which connects said central portion (82") to said feed section (6D) of said fourth separator (60). Device (1) according to any one of claims 1 to 9, characterized in that said supply means comprise: - at least one supply pipe (70) operatively connecting said outlet section (I ”) of said electrostatic precipitator (450) to said second charging section (42 ') of said second pipe (42), - a drive device (77) for acting on said raw flour with sufficient traction to overcome the level difference between said outlet section (11 '") of said electrostatic precipitator (450) and said second loading section (42' ) of said second tube (42). Device (1) according to any one of claims 1 to 10, characterized in that said first part (33 ') of said second tube (42) is constructed below said first plane (101) such that said point of minimum height (72) is located below said third relative plane (103). Device (1) according to any one of claims 10 to 11, characterized in that said first tube (32) comprises: - a first part (23 ') having a U-shape upside down, which is constructed above said first relative plane (101); - a second rectilinear part (23 ”) connected to said first part (23 '), which is constructed to a position close to that of said supply section (1D) of said electro-filter (450); - a fitting part (23 '") which connects said rectilinear part (23") to said supply section (11') of said electrostatic precipitator (450). Device (1) according to claim 12, characterized in that said first loading section (32 ') of said first tube (32) is defined by said second rectilinear part (23 ") in a position close to said first plane ( 101).