WO2014082716A1

WO2014082716A1 - Method for operating a regenerator (pebble heater) and regenerator

Info

Publication number: WO2014082716A1
Application number: PCT/EP2013/003483
Authority: WO
Inventors: Christian GÜNTHER; Michael Wahl
Original assignee: Saarstahl Ag
Priority date: 2012-11-30
Filing date: 2013-11-19
Publication date: 2014-06-05
Also published as: EP2926074B1; EP2926074A1; DE102012023517A1

Abstract

The invention relates to a method for operating a regenerator (1) for generating hot blast air for a steelmaking or steel treatment process, or a chemical process, wherein cold gas and hot gas is cyclically guided through a bulk material located in an annular space (4) between a hot grid (2) and a cold grid (3) surrounding the hot grid (2), and wherein a quantity of bulk material is removed from the annular space (4) in recurring cycles. The invention further relates to a regenerator. In order to achieve that on the one hand, the bulk material expanding during the hot phase does not deform and/or destroy the cold grid (3), and on the other hand, the bulk material particles do not get further eroded under alternating thermal stress, according to the invention during the phase of the cold gas application, or shortly before, or shortly thereafter, a defined quantity of bulk material determined by measuring means (20) is discharged from the bulk material through floor openings of the annular space (4).

Description

Method for operating a regenerator (Pebble Heater) and regenerator itself

The invention relates to a method for operating a regenerator, for example in the form of a pebble heater, for generating hot blast for a steelmaking / treatment process or a chemical process in which cyclic cold gas and hot gas is passed through a bulk material in each opposite direction, which is located in an annulus between a hot grid and a cold grid surrounding the hot grid, and wherein a lot of bulk material is removed from the annulus in recurring cycles, and a regenerator itself, according to the preamble of claims 1 and 8.

Regenerators of this type are, for example, in the

Steel production or steel treatment used for temperatures above 800 ° C. In the blast furnace and

Converter operation serve such regenerators for

Production of hot blast, where temperatures in the range of 1200 ° C are required. Regenerators of this type are known from US 2,272,108.

It is also known that these regenerators of the type mentioned above have an annular space between an inner hot grid and an outer cold grid, in which the bulk material is contained as a heat transfer medium. Consequently

one differentiates between two operating phases, a hot phase and a blowing or cold phase. In the hot phase, hot gases are passed through the bed and the sensible heat stored therein. In the blowing or cold phase, cold gases are conducted in the opposite direction through the bed, whereby the heat is transferred from the bed to the cold gas. Hot grate and cold grate are closed via openings or mesh so that the opening or mesh size is selected so that gases can pass through unhindered, but not the bulk material. That is, the particle or grain size of the bulk material, called Pebbles, is greater than the opening or

Mesh size of hot grid and cold grid.

The hot grid consists of firebricks, or stones made of other refractory materials. The cold grate consists essentially of perforated metal.

As bulk material (pebbles) usually balls of ceramic material, for example made of aluminum oxide are used.

It has to be considered that the bulk material undergoes thermal attack, i. during heating expands. So it comes in the said annulus of the regenerator to mechanical stresses, and then to increasing compaction both the cold grate and the

Hot grid can damage. These

Thermal cycling thus means that the bulk material more and more compacted, and thus destroys the hot grid in the long run.

From EP 0 908 692 A2 it is known from the

Regenerator during the passage of hot gas, ie in the hot phase, a defined amount of bulk material

To reduce the applied compressive stress on hot and cold grate. This take hollow chambers of Hot-dry bulk material, which by thermal

Expansion in the hot phase, bulk quantities durchschiebt by thermal expansion through an opening. The drained bulk material is over a

Transport gas stream then led back up to the regenerator to refill it there.

Already by the thermal expansion in the hot phase and thereby enforced forced passage of the bulk material through openings, and in particular by the transport of the same via a gas stream, the grains (pebbles) of the bulk material are severely eroded.

In addition, the Pebbles be discharged in the aforementioned prior art hot and by the

Transport gas stream are cooled very quickly. The mechanical stress is thus still the strong thermal cycling, which further enhances the erosion of Pebbles. The invention is therefore based on the object

Method for operating a regenerator, as well as a regenerator itself to improve so that the bulk material treated much gentler, and also the reduction of compressive stresses in the regenerator is more effective.

The object is in a method of the generic type according to the invention by the

characterizing features of claim 1 solved.

Further advantageous embodiments of

Process according to the invention are specified in the dependent claims 2 to 7. With regard to a regenerator itself is the

Asked task according to the invention by the

characterizing features of claim 8 solved. Further advantageous embodiments of the regenerator are specified in the remaining dependent claims.

The core of the method according to the invention is that from the bulk material in the cold phase or shortly before the phase of Heißgasbeaufschlagung a defined, determined by measuring means amount of bulk material is discharged through bottom openings of the annular space.

So it will be different than in the prior art

Bulk material discharged in the cold phase and the

Thermal cycling thus reduced. Thus, the bulk material is treated much gentler. A mechanical displacement of the bulk material in the

Cold phase, or shortly before or shortly thereafter is thus considerably less erosive.

In a further advantageous embodiment, it is stated that the discharged bulk material quantity is passed over a weighing or Füllmaßbestimmung until the amount of bulk material to be discharged is reached. This means that the amount of discharged bulk material is calculated and measured exactly to the expected thermal expansion, or can be measured.

The bulk material, i. the pebbles trickle or roll in and out of gravity

Conveying system, for example, a bucket elevator, or another vertical conveyor such as pocket conveyor or

Belt bag conveyor can be. In this case, the bulk material can initially in a contained in the conveyor or

incoming collecting vessel enter, from where it then can be promoted above the conveyor to the top.

In a further advantageous embodiment it is stated that the discharged bulk material as

Buffer storage in a conveyor or a

Collecting container initially temporally lingering

is cached. Thus, there is no immediate refilling. Thus, the conveyor or the collection container acts as a buffer.

A significant additional refinement in this respect is that the bulk material remains stationary in the conveyor or collecting container until the bulk material has cooled completely, before it is then moved on again for backfilling. Thus, in the sense described above, a gentle, preferably erosion-reduced mechanical treatment of the bulk material during the backfilling can take place, because the bulk material can first cool down completely in the UNWIRED state before it is moved again for refilling. That It is achieved with the fact that the bulk material in the warm state as little as possible moves to erosion in mutual

To avoid stringing together. In a further advantageous embodiment, it is stated that in the design of the bulk material to be discharged, the discharge pipes are taken into account in their volume such that the quantity of bulk material still trickling out after closing slides on the discharge pipe or discharge pipes is automatically taken into account in the desired target quantity. Thus, for example, if the sliders are located directly at the bottom of the regenerator, or at the top of the discharge lines, they are then closed when the already dehydrated and collected in a cup bulk material plus the still in the drain pipe after closing the slide

existing and still trickling amount of bulk material in sum corresponds to the predetermined discharge amount. In a further advantageous embodiment, it is stated that the discharged bulk material after Füllmaß- or weight determination via a conveyor, for example, a

Bucket elevator is conveyed upwards to a return of bulk material in the annular space of the regenerator. Unlike the prior art described above, the bulk material is not passed through a gas flow through a pipe up, but by a conveyor, for example, a bucket elevator, whereby the bulk material quite considerably

less mechanical stress is exposed. Thus, the bulk material itself has a significantly longer life.

In a particularly advantageous embodiment is stated that the äage- or Füllmaßbestimmung integral

Part of the conveyor, and thus of the

Return process of the discharged and returned recycled bulk material is.

As a result, the device is considerably simplified in the mode of operation, and it is not necessary to provide a separate mass determination between discharge lines and conveyors.

With respect to a regenerator of the generic type, the invention consists in that the discharge opening is connected via a pipe to a conveyor, preferably a vertically mounted bucket elevator, into which the bulk material trickles and from there to

Regenerator upwards for the return of the bulk material in the annulus is conveyed, and that the conveyor, for example, a bucket elevator and the slide for draining and for backfilling the discharged bulk material on a control device are operated controlled, in which also the hot and cold cycles of the regenerator are regulated. In this way, the bulk material is gently discharged and transported back. The design of the drain can be determined depending on the temperature and thus controlled in a simple manner. In this way, the

In addition, bulk particles (pebbles) may have already been discharged in the cold phase or before the hot phase, so that the temperature of the bulk material, i. reduces the pebbles during the discharge, and thus an additional mechanically gentle treatment of the bulk material during the discharge and the backfilling takes place.

The discharge amount is dimensioned so that in the

Hot phase at least the extent caused in the bulk material and the associated volume change is compensated by the bulk material discharge in this way.

Nevertheless, a substantial functional aspect remains that this counteracts compaction of the bulk material by increasing the compression of the intermediate spaces between the bulk material particles.

In addition, the hot grid and cold grid are effectively relieved mechanically in an effective manner.

In a further advantageous embodiment, it is stated that the conveyor or a conveyor operated by the conveyor

Collecting container integral weighing or

Füllmaßbestimmungsmittel at least one of

Partial delivery volumes, such as cups, bags, etc., containing, over which the discharged bulk material quantity can be determined.

In this way, the discharged bulk amount in dimensioned in each case, to the empirical values previously determined expected thermal expansion. The system is thus self-contained controllable.

In a further advantageous embodiment, it is indicated that the weighing or Füllmaßbestimmungsmittel of

Conveyor with a control device such

Correspond to this that the amount of

to be discharged bulk material via the control of the

Slider the discharge opening is controlled until the amount of bulk material to be discharged is reached, these slides are automatically closed. In a further advantageous embodiment, it is stated that the conveyor is preceded by a collecting container on the bulk material discharge, which with the weighing or

Füllmassbestimmungsmitteln initially independent of

Bucket elevator can be filled in the manner described above, and the bucket elevator then the amount of bulk material filled there from the collecting container upwards

transported.

So you can integrate the weighing or Füllmassbestimmungsmittel while in the conveyor or bucket elevator, but in this variant, the weight or Füllmassbestimmung remains separated from the pure conveyor.

Furthermore, it is advantageously designed that between the top delivery point and the Rücklfüllungungseingang in the annulus of the regenerator, a bulk material buffer is connected upstream, via which the upward

reclaimed bulk goods at short notice

stored intermediately and then controlled back into the annulus. This bulk material buffer is or can also be used as a pressure lock, because in the Transfer and return of the bulk material during the blowing or cold phase is an overpressure. For system operation with significant overpressure in the

Blasphase this is even necessary and advantageous. Since this yes a slide to the regenerator must be opened at the top, rauss previously on the bucket elevator

be returned initially in full, so that the bulk material can be backfilled in the shortest possible RückfüllVorgang.

In terms of the structure of the hot grid is in

advantageously further configured that the

Hot grid of stones is formed with a polygonal trapezoidal shape in the manner of pie pieces, which are laid in a ring, and thereby a plurality of rings are superimposed.

In a further advantageous embodiment, it is provided that the stones are hollow or hollow drilled and on the hot grid inside the regenerator a hole with a round cross-section and on the annular space of the

Regenerators facing outside have a hole with a square cross section, which in turn is closed with a ceramic lattice stone whose mesh size is smaller than the diameter of

Bulk particles (pebbles) is. In this hot grid, unlike in the above-cited EP 0 908 692 A2, intrusion of the bulk material into openings or interiors of the bricks is purposefully avoided. As a result, there is also no erosive expansive passage through openings of the hot grate caused by thermal expansion in the hot state.

An embodiment of the invention is shown in the figures. It shows:

Figure 1: regenerator in cross section

Figure 2: Regenerator with externally arranged

bucket elevator

Figure 3: hot grid in detail

Figure 4: Ring of hot stone

FIG. 1 shows a regenerator 1 in cross section. The interior 5 of the regenerator 1 is of hot gas

acted upon, and enclosed by a gas-permeable hot grid 2. When passing the hot gas through the hot grid 2, the bulk material 4 is heated. After AufheizVorgang cold gas is then passed through, which is then heated by the hot bulk material. in the

Bulk material, so the previously stored thermal energy is then used to heat the cold gas.

The hot grid 2 is of another coat, the

Cold grid 3 surrounded. Between hot grid 2 and cold grid 3 thus forms a cylindrical annulus 4, is arranged in the bulk material.

In the present case, ceramic grids are provided which prevent bulk material from entering the hot grid 2 and / or the heated interior space.

The cylinder space 4 filled with the bulk material (pebbles) between hot grid 2 and cold grid 3 opens at the bottom in FIG

Regenerator 1 in the discharge lines 10 from. The backfilling of the drained and outside the

Regenerator 1 upwards conveyed bulk material takes place at the top of the regenerator.

There are nozzles 7 and connected to them

Pipes arranged, which lead the back-filled bulk material from above by gravity again in the intermediate space 4 of the regenerator 1.

Figure 2 shows the regenerator 1 with the

Pipe guides as well as from the regenerator space outwardly, also inventive conveyor line of the bottom drained and top back again filled bulk material. The regenerator, as shown in Figure 2, as already seen in Figure 1, a

cylindrical outer shell on. The two ends of the cylindrical shell are closed off distally by means of covers 8 and 9. In the area of the lower lid, the discharge pipes 10 are arranged. The bulk material flows directly from the cylindrical space 4 of the regenerator 1 in the drain piping 10th

The refilling at the upper end of the regenerator 1 is also in the upper lid 8 arranged there

arranged. In the vertical next to the actual regenerator 1, the conveyor 14 is placed. At the lower end of the regenerator 1, the drain piping 10 are arranged so that under the action of gravity, the bulk material flows down, rolls or trickles. Since a plurality of radially distributed discharge pipes 10 are provided to ensure a uniform discharge of bulk material around the entire circumference of the

To ensure cylindrical space 4, the pipes 10 are placed over the entire course of their length in a steady sloping direction, so that no siphon effect arises. Because then the bulk would be there under gravity can no longer flow away.

All pipelines converge and discharge into an under conveyor, here shown as a bucket elevator, or into a bucket elevator integrated below

Collecting container 13. This container is provided with Füllmaß- or weight determination means. The before the

Hot phase to be deducted bulk material is calculated so that it corresponds to the previously determined, caused by thermal expansion of the bulk material volume increase. Will therefore be determined in this regard

Volume of bulk discharged, this relieves the

mechanical pressure on the hot grid and the cold grid. At the beginning of the discharge slide are opened at the drain pipes 10 in the regenerator 1 and it flows from bulk material. This then flows through the discharge

Pipes 10 down into the collection container 13 on or in the conveyor or bucket elevator. If the determined level or the determined weight of the amount of bulk material to be discharged is reached there, then the slider (s) are closed again.

Since the drainage pipes 10 have a volume, this "dead volume" must be taken into account in the determined quantity of bulk material to be discharged, so that the control, not shown here, in the case of

defined bulk material discharge or defined

Schütgutablassmenge taken into account.

Once this volume of bulk material to be discharged has been reached, the conveyor or bucket elevator is set in motion and conveys the discharged bulk material upwards to the upper end of the regenerator 1. There it flows again under the influence of gravity into an intermediate container 16, from where it is redefined, and optionally with at least one further slide via return pipes 17 and 7 directly into the regenerator 1 arranged Interspace 4 between cold grid 3 and hot grid 2 is backfilled. Said intermediate container is advantageously a pressure lock or connected to a pressure lock, or is operated as a pressure lock.

The promotion is compared to the above-described prior art, for the reasons already mentioned above, much gentler for the bulk material particles (Pebbles). FIG. 3 shows a single hot stone 21. The

Structure of the hot grid consists of these stones, which are stacked in stacked, each staggered rings, stacked ring by ring, like an annular wall.

As can be seen, the stones 21 are with

Through openings provided, which are so placed and contoured that in the installed state of the

Inside, so to the surrounding of the hot grid

Interior out as 22 Ausmündungen formed round, and outwards, so the space filled with bulk material out as outlets 23 are square. The square outlets 23 are with

heat resistant or ceramic grids 24

closed, so that exactly as in the aforementioned prior art, no bulk material can penetrate into the interior of the stones 21. For this purpose, the mesh size of the ceramic grid 24 is smaller than the smallest grain size of the bulk material (Pebbles).

The ceramic grids 24 are fixed in the bricks 21 with ceramic adhesive.

FIG. 4 shows one of hot-wire stones 21

assembled ring. The hot grid thus consists of a plurality of superimposed and with each other bonded rings, to a polygonal cylinder tube as shown in Figure 1 as a hot grid 2.

Reference numeral regenerator

hot grid

cold grid

Space for bulk material (pebbles)

Inner space, hot gas entering heating phase

7 return stubs / pipes

8 Upper regenerator lid

9 Lower regenerator lid

10 Bottom drain spigots, drain piping

11 outer jacket of the regenerator

13 collection containers

14 conveyor (bucket elevator)

15 pipe section

16 Upper intermediate container

17 Upper return lines

20 Füllmaß- or weight determination means

21 hot stone

22 Outlet of the passage opening in

Hot ruststone inside

23 Outlet of the passage opening in

Hot stone for bulk material interstice

24 grilles / filters, ceramic

Claims

claims

1. A method for operating a regenerator, for example in the form of a pebble heater, for the production of

Hot blast for a steelmaking / treatment process or a chemical process in which cyclic cold gas and hot gas are passed in opposite directions through a bulk material located in an annulus between a hot grid and a cold grid surrounding the hot grid, and wherein

repeating cycles a lot of bulk material is removed from the annulus and later backfilled, characterized

that from the bulk material in the phase of

Kaltgasbeaufschlagung or shortly before or after a defined, determined with measuring means amount of bulk material is discharged through bottom openings of the annular space.

2. The method according to claim 1,

characterized,

that the discharged bulk material is passed over a weighing or Füllmaßbestimmung until the defined amount of bulk material to be discharged is reached.

3. The method according to claim 1 or 2,

characterized,

that the discharged bulk amount as

Intermediate storage amount in a conveyor or a collection initially lingering time

is cached. Method according to claim 3,

characterized,

that the bulk material remains stationary in the conveyor or collecting tank until the bulk material has completely cooled down, before it is then moved again for backfilling.

Method according to one of the preceding claims 1 to 4,

characterized,

that in the design of the to be omitted

Volume of bulk the discharge pipes are taken into account in their volume so that the after closing of sliders on the discharge pipe or the discharge lines still trickling amount of bulk in the desired target amount automatically

is taken into account.

Method according to one of the preceding claims, characterized

that the discharged bulk material is passed by Füllmaßoder weight determination via a conveyor up to a return of bulk material in the annular space of the regenerator.

Method according to one of the preceding claims, characterized

that the filling or Füllmaßbestimmung determining an integral part of the conveyor, and thus the

Return process of the discharged and returned recycled bulk material is.

Regenerator, eg in the form of a pebble heater, for generating hot blast for a steelmaking / treatment process, or a chemical process, with a bulk material through which cyclically

alternately cold gas and hot gas is passed, wherein the bulk material is in an annulus between a hot grid and a cold grid surrounding the hot grid, and the annulus with at least one closable with sliders and reveal

Ablassöffnung is provided, and with means for reclaiming the discharged bulk material in the regenerator, in particular for carrying out the method according to one of claims 1 to 5,

characterized,

that the discharge opening is connected via a pipe (10) with a conveyor (14), in which the bulk material trickles and from there to

Regenerator upwards for the refilling of the

Bulk material in the annular space (4) is conveyed, and that the conveyor (14) and the slide to the

Draining and for recirculating the discharged bulk material via a control device

operated in which also the hot and cold cycles of the regenerator are regulated.

, Regenerator according to claim 8,

characterized,

the conveyor (14) is a vertical conveyor in the form of a bucket elevator, or pocket conveyor, or belt bag conveyor.

0. Regenerator according to claim 8 or 9,

characterized,

that the conveyor (14) or a collection container operated by the conveyor contains integral weighing or filling measurement means (20), or

at least at one of the filling cups or bags of the Contains conveyor over which the discharged bulk quantity can be determined.

11. Regenerator according to claim 10,

characterized,

that the weighing or Füllmaßbestimmungsmittel (20) of the conveyor corresponds to a control device such that in this case the amount of

To be discharged bulk material on the control of the slide of the discharge opening until the amount of bulk material to be discharged is reached, is controllable.

12. Regenerator according to claim 10 or 11,

characterized,

that the conveyor (14) on the bulk material discharge

Collecting container (13) is connected upstream, which is filled with the weighing or Füllmassbestimmungsmitteln (20) initially independent of the conveyor in the manner described above, and the conveyor then transported there filled bulk amount from the sump upwards.

13. Regenerator according to claim 12,

characterized,

that between the top delivery point of the conveyor and the Rücklfüllungungseingang in the annular space (4) of the regenerator, a bulk material buffer (16) is connected upstream, over which the upwardly conveyed bulk material is initially temporarily interposed and then controlled backfilled in the annular space.

14. Regenerator according to claim 13,

characterized,

that the bulk material buffer (16) a pressure lock is.

15. Regenerator according to one of claims 9 to 14,

characterized,

that the hot grid (2) consists of stones (21) with a polygonal shape in geometric form of a

Pieces piece is formed, which are laid into a ring, and thereby a plurality of rings are superimposed.

16. Regenerator according to claim 13,

characterized,

that the stones (21) are hollow or hollow drilled and have a hole with a round cross-section (22) on the hot-wire inside of the regenerator and a hole with a square cross-section (23) on the outside facing the annulus of the regenerator, which in turn has a square cross-section (23) ceramic

Grids (24) are closed, whose

Mesh size smaller than the diameter of the

Bulk particles (pebbles) is.