EP0952397A1 - Conveyor for removing bulk material from a boiler - Google Patents

Abstract

The conveying device includes a conveyor to take the ash or slag along a conveying section. The conveyor can be cooled by coolant. Ash or slag and the coolant are separated from each other by a heat-permeable dividing wall in the form of conveyor belts (30a, 30b). The ash or slag is cooled by transmission of heat to a coolant moving separately from it.

Description

The invention relates to a conveying device for discharging a conveyed good, in particular slag or ash, from a boiler, which comprises a conveying means for conveying the conveyed good along a conveying path. The invention also relates to a method for discharging the conveyed material from a boiler, in which the conveyed material is cooled.

Conveying devices for discharging slag from a boiler are also referred to as deslagging plants or boiler ashtrays. Such purification plants are required, for example, where the ash content of the fuel for firing the boiler, for example coal, is sintered or granulated, that is to say coarse. A known form of a detoxification system is a so-called wet purifier. This has a tub that is filled with water and has an opening at the top. In the tub of the wet slag remover there is a conveying means, for example a scraper conveyor, which comprises a conveying path. The conveyor line runs below the opening in the trough approximately parallel to the bottom thereof and includes a conveyor slope that ends above the water level in the trough and above a discharge opening.

Such a wet slag remover is suitable for interacting with a boiler which has an opening below a grate which is surrounded by a collar which projects from the bottom of the boiler. When the wet slag remover is in its operating position, the collar of the boiler protrudes from above into the opening of the trough, so far that the mouth of the collar is below the water level of the water in the trough. In this way, the burned-out slag can fall through the grate of the boiler and through the opening of the boiler and its collar into the water bath of the wet slag remover. The initially hot slag is cooled. It continues to fall onto the conveyor track of the scraper conveyor and is first conveyed by it to the conveyor slope and along this from the water bath. At the end of the conveyor line at the highest point of the conveyor incline, the slag falls off the scraper conveyor through the discharge opening, for example into a container arranged below it. The slag is still wet. Part of the water absorbed by the slag can already flow off, while the slag is conveyed above the water level in the tub of the wet slag remover. Nevertheless, the amount of water contained in the slag after removal is considerable. This leads to an undesirable water loss with a corresponding refill requirement. In addition, the water initially taken up by the slag and later emerging from the slag is heavily contaminated with environmentally unfriendly substances. This water must therefore first be treated laboriously before it can be released into the environment.

The fact that the collar of the boiler opens below the water level in the tub of the wet slag remover also has the effect that the interior of the boiler is hermetically sealed from the surroundings by means of the water. In this way, a slight negative pressure of approx. 50 mm H ₂ O (approx. 490 Pascal) can be kept inside the boiler. This seal also works if the boiler expands due to its heating. In this case, the collar protrudes deeper into the water bath.

The aim of the present invention is to avoid the environmental pollution occurring in the prior art.

This goal is achieved according to the invention by a conveyor device of the type mentioned at the beginning, in which the conveyor can be cooled with a coolant in such a way that the material to be conveyed and the coolant are at least through a heat-permeable partition are separated from each other. The core idea of the invention is accordingly not to cool the material to be conveyed, in particular hot slag, directly by a water bath, but indirectly by a cooled conveying means. Since the conveying means no longer comes into contact with the coolant in this way, the latter can no longer be contaminated by the conveyed material. The coolant, preferably water, therefore remains unloaded and can accordingly either be released to nature or reused. It is also achieved with the device according to the invention that no coolant is lost by being carried away with the slag. It is even possible to introduce a closed coolant circuit from which no coolant is lost and therefore no fresh coolant has to be supplied. If water is used as the coolant, essentially no fresh water needs to be supplied to the device. This results in considerable cost savings. It is also possible to use a different coolant depending on the requirements and suitability. However, due to its high availability and high thermal capacity, water is the preferred coolant.

The conveyor is preferably a chain conveyor, for example a scraper conveyor.

The conveying means preferably has at least one coolant channel which runs along at least part of the conveying path and is part of a coolant circuit which is closed at least within the conveying device. A coolant circuit closed within the conveying device represents a particularly favorable variant of the device according to the invention, in which the conveyed goods and the coolant are separated from one another by a heat-permeable partition.

The conveying device also preferably has at least one deflection and is designed in such a way that the conveying path is extended beyond a minimum required for the complete removal of the conveyed goods. The extended, cooled conveying means makes it particularly easy to cool down hot slag to the temperature suitable for removal. The extended funding means that a larger cooling surface and a longer cooling time are available.

In the case of a grant, at least one such extended conveyor track is used a revolving traction means, the leading run of which conveys the material to be conveyed to the end of the conveying path, preferably achieved in that the conveying path runs both along the leading and along the returning run. The material to be conveyed is first conveyed from the returning run of the traction device in a direction that leads away from the end of the conveying path. The conveying direction of the conveying means is reversed at a deflection. From the point of deflection, the leading strand of the conveying device conveys the material to be conveyed along the conveying path to the end. Since there is always a leading and a returning strand in any case with a conveyor with a rotating traction means, the use of both the leading and the returning strand to extend the conveyor path means no or only an insignificant additional effort compared to a conveyor that only conveys in one direction. The available cooling surface and the cooling time are, however, considerably longer than with a one-way funding.

Preference is given to a conveying device which additionally comprises sealing means in order to keep the pressure in the boiler lower than the ambient pressure, and which is characterized in that the sealing means comprise a dry lock chamber through which the material to be conveyed can exit from the inside of the boiler. In a preferred embodiment, this lock chamber is designed as a double pendulum flap or alternatively as a cellular wheel lock. The conveying means and lock chamber are preferably arranged relative to one another in such a way that the material to be conveyed falls into the lock chamber at the end of the conveying path and exits through the lock chamber due to the action of gravity. By means of such a lock chamber, a negative pressure can be kept in the boiler without having to accept that the conveyed material gets wet.

A crusher is preferably arranged between the end of the conveyor line and the lock chamber. With the help of this crusher, the slag removed from the boiler can be crushed. Since this occurs in the preferred arrangement of the crusher before the slag enters the lock chamber, the lock chamber can be reliably prevented from being blocked by large pieces of slag.

Between the end of the conveyor line and the lock chamber, a flexible discharge chute is also preferably provided, which is particularly preferably located between the end of the conveyor line and the crusher. Together With a preferred conveyor device that can be attached to the boiler, relative movements between the conveyor line and the crusher and the lock chamber can be compensated for with the aid of the flexible discharge chute. Such movements can occur when the conveyor is attached to the boiler and moves up and down due to the thermal expansion of the boiler while the crusher and lock chamber are attached to the solid ground.

The object is also achieved according to the invention in a method of the type mentioned at the outset, in which the cooling of the material to be conveyed takes place essentially by heat transfer to a coolant which is conducted separately from the material to be conveyed. This is the method by which the device described above operates and accordingly has all of its advantages. In a preferred variant of the method, the material to be conveyed is additionally sprayed with an amount of a coolant which is dimensioned such that the coolant evaporates completely. In this process variant, the coolant and the slag come into contact with one another, but since the coolant evaporates completely, the slag is completely dry after cooling. When the coolant evaporates, hardly any harmful substances are dissolved in the coolant, so that the coolant is essentially free of contamination.

For the aforementioned reasons, water is preferably used as the coolant.

Fig. 1

einen Kessel-Entascher in der Seitenansicht, teilweise geschnitten;

Fig. 2

eine alternative Ausführungsform des Kessel-Entaschers in der Seitenansicht, teilweise geschnitten;

Fig. 3

einen vergrößerten Ausschnitt der Seitenansicht der Kessel-Entascher aus Fig. 1 und Fig. 2 im Längsschnitt;

Fig. 4

einen vergrößerten Querschnitt durch die Kessel-Entascher in Fig. 1 oder 2;

Fig. 5

eine Aufsicht auf einen längsgeschnittenen vergrößerten Ausschnitt der Kessel-Entascher nach Fig. 1 oder 2;

Fig. 6

eine Rückansicht des Antriebskopfes der Kessel-Entascher nach Fig. 1 oder 2 im Längsschnitt; und

Fig. 7

einen Querschnitt durch den Antriebskopf aus Fig. 6.

The invention will now be explained in more detail using an exemplary embodiment with the aid of the drawings. These show:

Fig. 1

a kettle ashtray in side view, partially cut;

Fig. 2

an alternative embodiment of the ash extractor in the side view, partially cut;

Fig. 3

an enlarged section of the side view of the ash-ash removal from Fig. 1 and Fig. 2 in longitudinal section;

Fig. 4

an enlarged cross section through the boiler ashtray in Fig. 1 or 2;

Fig. 5

a plan view of a longitudinally sectioned enlarged section of the boiler ash extractor according to Fig. 1 or 2;

Fig. 6

a rear view of the drive head of the boiler ash extractor according to Figure 1 or 2 in longitudinal section. and

Fig. 7

6 shows a cross section through the drive head from FIG. 6.

Fig. 1 shows a boiler ash extractor 10, the essential component of which is a chain conveyor designed as a scraper conveyor 12, which opens into a flexible discharge chute 14. A crusher 16 connects to the flexible discharge chute, which in turn ends in a lock chamber designed as a double pendulum flap 18. A trough chain conveyor 20 is located below the double pendulum flap 18.

The scratch conveyor 12 has an airtight housing serving as a trough 22. The trough 22 is provided with a trough riser 24. At its upper edge, this has a flange 26, by means of which the scraper conveyor 12 is fastened to a boiler. For this purpose, the boiler also has a flange, which is located at the lower end of a collar, which surrounds an opening on the underside of the boiler below its grate. The scraper conveyor 12 is flanged airtight to the boiler. Its trough 22 opens into the flexible discharge chute 14, which is also airtight and allows a vertical relative movement between the trough 22 and the crusher 16 located below the flexible discharge chute 14. Such relative movements can occur because the scraper conveyor 12 is flanged to the boiler and is therefore moved up and down due to the thermal expansion or cooling of the boiler while the crusher 16 is firmly connected to the ground. The flexible discharge chute 14, the crusher 16 and the double pendulum flap 18 are also all airtight. This results in an interior of the trough 22, the flexible discharge chute 14, the crusher 16 and the double pendulum flap 18 which is connected to the inside of the boiler and which is sealed from the surroundings by means of the double pendulum flap 18, so that a desired negative pressure is present in this interior of about 490 Pascal.

In the trough 22 there are two conveyor tracks 30, namely an upper conveyor track 30a and a lower conveyor track 30b, which together define a conveyor track. There is a rotating one on both sides of this conveyor line Traction means 32. Carriers 34 extend between the two traction means 32, which are moved along by the traction means 32 on the conveyor tracks 30 and thereby take along conveyed goods located on the conveyor tracks 30. The direction of conveyance is indicated by arrows 36.

The revolving traction means 32 are deflected with the aid of two deflections 38 and 40, so that an upper returning run 32a and a lower, leading run 32b of the pulling means 32 result. The deflection 38 is part of a tensioning station for tensioning the traction means 32. For this purpose, the deflection 38 is slidably mounted in the longitudinal direction of the scraper conveyor 12. The deflection 40 is driven by a motor 42 and in turn drives the traction means 32 together with the drivers 34.

The conveyor tracks 30 and the side walls of the trough 22 adjoining them are equipped with coolant channels 50 (see also FIGS. 3 and 4). Water serving as coolant can enter the coolant channels 50 through inlets 52 and 54 and exit again through outlets 56 and 58. In addition, there is a spray device 60 inside the trough 22, by means of which hot conveyed goods can be sprayed with a coolant, preferably water, if the conveyed goods are too hot. The amount of coolant sprayed is dimensioned such that the coolant evaporates completely, so that the material to be conveyed remains dry as a result.

The material to be conveyed is ash or slag, which falls through the trough riser 24 onto the upper conveyor track 30a and is transported there by means of the returning run 32a of the traction means 32 and the drivers 34 along the conveyor track 30a in the conveying direction indicated by arrow 36, that is to say initially in the direction of the deflection 38. The conveying speed is approximately 0.02 m / sec. While the hot ash or slag is being conveyed on the conveyor track 30a in the designated direction, water is simultaneously directed through the cooling channels 50 against the conveying direction. In this way, the conveyor track 30a is cooled and thus also indirectly the hot ash or slag on the conveyor track 30a. At the end of the upper conveyor track 30a, the hot ash or slag falls onto the lower conveyor track 30b. At this point, the hot ash or slag may be sprayed with additional coolant, which then evaporates, using the spray device 60. On the lower conveyor track 30b, the hot ash or slag is conveyed from the leading runs 32b of the traction means 32 and the drivers 34 to the end 62 of the conveyor line. The lower conveyor track 30b is also cooled in countercurrent with water. In this way it is ensured that the hot ash or slag at the end 62 of the conveyor line is cool enough for further treatment. At the end 62 of the conveyor line, the ash or slag falls through a funnel 64 and through the flexible discharge chute 14 into the crusher 16. There larger pieces of slag are crushed before they pass out through the lock chamber equipped with a double pendulum flap 18. There, the ashes and slag are removed by means of the chain conveyor 20.

On its long sides, the trough 22 has a plurality of flaps 66 which close a plurality of lateral openings in the trough 22 through which the scraper conveyor 12 can be emptied in an emergency.

A plurality of downwardly projecting supports 68 are also attached to the trough 22. At the lower end of the supports 68, wheels 70 are attached, which are located above rails 72, which run perpendicular to the plane of the drawing. When the boiler ash extractor 10 is detached from the boiler, it can be placed on the rails 72 by means of the supports 68 and the wheels 70 and can thus be moved transversely to its longitudinal direction.

So that the depth of fall between the end 62 of the conveying path and the outlet of the double pendulum flap 18 is given in the boiler ash extractor 10 from FIG. 1, the funnel 64, the flexible discharge chute 14, the crusher 16 and the double pendulum flap 18 and the chain conveyor located underneath 20 housed in a pit 65.

In order to make this pit 66 superfluous, the alternative boiler ash extractor 10 'shown in FIG. 2 is provided. In this case, the trough 22 'and the conveyor tracks 30a' and 30b 'are extended to the side of the trough elevation 24' and form a conveyor slope 74 with an obliquely upwardly inclined section of the lower conveyor track 30b '. In this way, the material to be conveyed on the conveyor track 30b 'is not only conveyed laterally but also upwards. The end 62 'of the conveyor line is so far above the ground, so that the underlying components of the boiler ash extractor 10', namely its funnel 64 'and the flexible discharge chute 14', the crusher 16 ', the double pendulum flap 18' and the Trough chain conveyors 20 'do not need to be sunk in a pit.

Otherwise, the structure and mode of operation of the boiler ashtray 10 ′ are identical to that of the boiler ashtray 10.

Details of the scratch conveyors 12 and 12 'from FIGS. 1 and 2 can be seen in FIG. 3. This shows an enlarged section of a longitudinal section approximately through the center of the scraper conveyor. A rear side wall of the trough 22 and the trough elevation 24 can be seen. Starting from the rear side wall of the trough 22, the upper (30a) and lower (30b) conveyor tracks extend in a plane running perpendicular to the plane of the drawing. Below the conveyor tracks 30 there are coolant channels 50, in which water flows as coolant in the direction indicated by an arrow. A circumferential traction means 32 runs along the conveyor tracks 30. The returning run 32a of the traction means 32 runs above the upper conveyor track 30a, while the leading run 32b of the traction means 32 runs above the lower conveyor track 30b. The direction of movement of the leading and returning runs 32a and 32b is identified by an arrow. Carriers 34 are attached to the traction means 32 and extend in a direction perpendicular to the plane of the drawing. The drivers 34 each have a conveyor plate 80 on their front side, in front of which the material to be conveyed is pushed and which is stiffened on its rear side with a U-shaped profile 82.

The cross section through the scraper conveyors 12 and 12 'in Fig. 4 reveals further details. Again, the trough riser 24 can be seen with its lateral flange 26 for connection to the boiler. The trough 22 is located under the trough elevation 24. The upper and lower conveyor tracks 30a and 30b extend between the side walls thereof. It can be seen that seven coolant channels 50 are arranged below each of the two conveyor tracks 30, which run in a direction perpendicular to the plane of the drawing. In addition, two coolant channels 50 are arranged on both sides of the conveyor tracks 30 on the side walls of the trough 22.

The flaps 66 can also be seen, with which a plurality of lateral openings in the trough 22 are closed, which serve in an emergency to empty the scraper conveyor 12 or 12 '.

In Fig. 4, a driver 34 is shown above the conveyor tracks 30, namely above the upper conveyor track 30a in the rear view of the U-profile 82 and above the lower conveyor track 30b in the front view of the conveyor plate 80. The driver on both sides 34 a traction device 32 runs in each case.

5 shows a conveyor track 30 in plan view and partially in section, so that the coolant channels 50 located under the conveyor track 30 can be seen. In addition, a run of a traction means 32 and two carriers 34 attached to it are shown with their conveyor plate 80 and the stiffening U-profile 82. Wear rails 84 are attached to the side of the traction means 32 to protect the side walls of the trough 22.

FIG. 6 is a rear side view of that end of the trough 22 which carries the driven deflector 40. A sprocket causing the deflection 40 is indicated. Where its shaft 90 penetrates the wall of the trough 22, a flange 92 is provided which serves to connect a drive including the drive motor. Also shown in dashed lines are some members of the traction means 32 together with the drivers 34.

7 is a cross section along the shaft 90 of the deflection 40. A sprocket 94 serving as deflection 40 can be seen, which is mounted on the shaft 90. In addition, two drivers 34 are shown, one in the view of the conveyor plate 80 and one in the rear view of the stiffening U-profile 82. In addition, FIG. 7 shows a fastening for the drive.

Claims (17)

Conveying device for discharging a conveyed good, in particular slag or ash, from a boiler, which comprises a conveying means for conveying the conveyed good along a conveying path,
characterized in that the conveying means can be cooled with a coolant in such a way that the material to be conveyed and the coolant are separated from one another at least by a heat-permeable partition (30). Conveying device according to claim 1, characterized in that the coolant is water. Conveying device according to claims 1 and 2, characterized in that the conveying means is a chain conveyor. Conveying device according to one of the preceding claims, characterized in that the conveying means has at least one coolant channel (50) which runs along at least part of the conveying path and is part of a coolant circuit which is closed at least within the conveying device. Conveying device according to one of the preceding claims, characterized in that the conveying means has at least one deflection (38, 40; 38 ', 40') and the conveying path is extended beyond a minimum dimension required for the complete removal of the conveyed goods. Conveying device according to claim 5, with at least one revolving traction means (32), the leading run (32b) of which conveys the material to be conveyed to the end (62, 62 ') of the conveying path, characterized in that the conveying path both along the leading (32b) and along of the returning (32a) run. Conveying device according to one of the preceding claims, which additionally comprises sealing means in order to keep the pressure in the boiler lower than the ambient pressure,
characterized in that the sealing means comprise a dry lock chamber through which the material to be conveyed can exit from the inside of the boiler. Conveying device according to claim 7, characterized in that the lock chamber comprises a double pendulum flap (18). Conveying device according to claim 7, characterized in that the lock chamber is designed as a cellular wheel lock. Conveying device according to one of claims 7 to 9, characterized in that the conveying means and lock chamber are arranged relative to one another such that the material to be conveyed falls at the end (62, 62 ') of the conveying path into the lock chamber due to the force of gravity exiting through the lock chamber. Conveying device according to one of claims 7 to 10, characterized in that it has a crusher (16, 16 ') which is arranged between the end (62, 62') of the conveyor section and the lock chamber. Conveying device according to one of claims 7 to 11, characterized in that it has a flexible discharge chute (14, 14 ') between the end (62, 62') of the conveying section and the lock chamber. Conveying device according to claim 12, characterized in that the flexible discharge chute (14, 14 ') is arranged between the end (62, 62') of the conveyor section and the crusher (16, 16 '). Conveying device according to one of the preceding claims, characterized in that it can be fastened to the boiler. Method for discharging a conveyed good, in particular slag or ash, from a boiler in which the conveyed good is cooled, characterized in that the cooling takes place essentially by heat transfer to a coolant which is carried separately from the conveyed good. A method according to claim 15, characterized in that the material to be conveyed is additionally sprayed with an amount of a coolant which is dimensioned such that the coolant evaporates completely. A method according to claim 15 or 16, characterized in that water is used as the coolant.

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