DE2714380A1 - DEVICE AND PROCEDURE FOR DIVIDING - Google Patents

Description

KRAUS & VVEISERT

PATENT LAWYERS * "

DR. WALTER KRAUS DIPLOMCHEMIKER · D R.-l N G. AN N EKÄTE WEISERT DIPL-ING. SPECIALIZATION CHEMICALS IRMGARDSTRASSE 15 · D-8OOO MUNICH 71 · TELEPHONE 0 8 9/79 70 77-7 9 70 78 · TELEX O5-212156 kpat d

TELEGRAM CRAUS PATENT

1486/7 WK / rm

BETHLEHEM STEEL CORPORATION, Bethlehem, Pa. / UNITED STATES

Device and method for making lumpy

The invention relates to a balling device and a continuous method of balling carbonaceous materials in an agglomeration drum (also referred to herein as an agglomeration drum) to a relatively uniform size.

The carbonaceous materials are preferably used by the device according to the invention and the device according to the invention Process made lumpy or agglomerated in pellet form. Once calcined, the pellets can

709841/0894

- ν - <! / U380

used instead of metallurgical coke in the operation of a blast furnace. For the sake of simplicity is directed the following description of the invention relates to an apparatus and method for forming such pellets.

In the steel industry, large quantities of coke are required every year to produce blast furnace iron, which in turn is converted into steel. Coke suitable for blast furnaces requires a mixture of coals for its production with high and low volatile content (preferably with a low sulfur and a low Ash content) that can be coked. Furthermore, such coals must be coked in by-product coke ovens of the slot type which create serious air and water pollution problems. The present invention now relates to an apparatus and method for producing agglomerates from carbonaceous Substances of relatively uniform size (preferably in pellet form) that can be further treated to make coke pellets to form that have the properties that make them suitable for use in blast furnaces instead of slot furnace coke do.

The coke pellets, e.g. the agglomerates, which can be obtained according to the invention, have the properties required for satisfactory functioning in a blast furnace. For example, they lead the melting process the necessary heat value and they are strong enough that they carry the furnace oiler. The pellets keep theirs physical integrity and they are resistant to crumbling. In this way they allow

709841/0894

27U380

the passage of the rising hot gas through the Möller above.

As far as the present invention with the Stükkigmachungsstufe employed in the known process for the production of agglomerates, e.g. coke pellets, it can It may be useful to summarize the general characteristics of such a process again.

Processes for the formation of agglomerates can be described in the following general terms:

1. Coal, typically made up of particulate bituminous Coal can exist, the size of which is sufficient that it passes through a sieve with a clear mesh size 4.76 mm passes through it is preheated to a temperature just below its softening temperature before them with the other components in an agglomeration drum is introduced. These other ingredients are (a) finely divided charcoal that is at a temperature has been preheated from about 538 to 649 ° C, and given- (b) pitch, which acts primarily as a binder the strength of the agglomerates in the agglomerating drum is formed to increase.

2. The mixture of these ingredients - warm particulate Coal, heated charcoal and possibly pitch - is put into an agglomeration or agglomeration drum convicted. Preheating the coal and the other components of the feed eliminates the need to in the agglomeration drum additional or supplementary

709841/0894

- Jf -

de heating devices to be provided. The components already contain the entire amount of heat that is required is to raise the temperature of the coal to a value above its softening point and to this Way of causing the agglomeration of the carbonaceous material.

During the agglomeration process, the agglomeration drum rotated to thoroughly mix the charcoal, charcoal and pitch and make the agglomerates, like they are made to subject to drum treatment. Increases during the intimate mixing of the ingredients the temperature of the coal particles as they absorb heat from the high temperature charcoal. The result is one partial distillation of the coal particles in such a way that the agglomerate materials have a loosely coherent form plastic sticky mass in the agglomeration drum. With such variations in the coke pelletization process, where pitch is used as a binder, the pitch continues to contribute to the agglomeration of the particulate Components within the agglomeration drum.

3. The agglomerates thus formed, known as "green agglomerates", i.e., uncured agglomerates, and which emerge from the agglomerating drum Without further processing, they do not have sufficient strength to withstand the heavy weight of a conventional Could withstand the blast furnace. The green agglomerates become therefore subjected to a final stage in which a calcination treatment at temperatures between about 732 and 982 ° C takes place.

709841/0894

i! 7U380

This treatment gives the pellets or agglomerates sufficient strength and abrasion resistance that allow their use as blast furnace coke instead of a conventional slit furnace product.

The present invention relates to stage 2, i.e. the formation of the green agglomerates or pellets in one Agglomeration drum. A key feature of this invention is that the agglomeration drum and the associated agglomeration processes, both of which are to be described in more detail below, contain green agglomerates or pellets of a relatively uniform size. The relative uniformity of the size of the agglomerates is critical, to ensure the successful operation of blast furnaces.

Before the actual description of level 2, known techniques should be described for comparison purposes. used in performing this stage. For example, U.S. Patent 3,316,585 discloses the use of a rotary scraper described, which is arranged within an agglomeration drum. The scraper or scrapers are located within the agglomeration drum so that agglomerated material is removed from the inner wall of the drum is removed and a relatively uniform layer of the agglomeration material on the inner wall of the drum is maintained. In US Pat. No. 2,697,068, another example of a combination of a rotating Agglomeration drum and a rotating scraper, which is arranged within this drum, described. With each of the in these two patents

709841/0894

27U380

described device lengths, however, the scraper and the drum device are designed so that a uniform Layer of agglomerated material is maintained along the inner wall of the drum.

In contrast to the devices according to your prior art the invention achieves a more effective agglomeration without the need for a uniform one To maintain a layer of agglomeration material over the entire length of the drum.

This is accomplished, according to the invention, by a device for chunking to control the size of the carbonaceous Materials and the formation of agglomerates obtained therefrom. The device according to the invention comprises a drum, having an inner wall which is rotatable about a central axis of the drum and also having inlet and outlet means for the introduction of the carbonaceous materials and the removal of the agglomerates from the drum and a rotating shaft extending into the drum and off the central axis of the drum Drum is offset. The device according to the invention is given by a plurality of first doctor blades Length which protrude from the shaft and which are designed to contain accumulated carbonaceous Scrape material from the inner wall of the drum as the drum and shaft are rotated, and a multitude characterized by second doctor blades of shorter length protruding from the shaft.

Advantageously, a plurality of annular ribs are attached to the inner wall of the drum, each

7 0 9 8 4 1/0894

annular rib in the path of rotation of one or more of the second doctor blades and wherein one or more of the first doctor blades is in the space between the ribs. The use of the annular ribs (or Walls), which are arranged at intervals around the inner wall of the rotating agglomeration drum, guaranteed a non-uniform layer of agglomeration material over the full length of the drum and thereby increases the relative residence time of the small or growing agglomerates and limits the contact between the large ones formed agglomerates and the growing agglomerates, all it takes to make agglomerates with a narrow size range are formed.

The invention is explained in more detail with reference to the accompanying drawings. Show it:

1 shows a longitudinal section through an agglomeration drum constructed according to the invention;

FIG. 2 is a full section, taken along line 2-2 of FIG. 1, of an operating system Agglomeration drum;

3 shows a partial section along the line 3-3 of FIG. 1; and

Fig. 4 is a partial perspective view showing the shape the inner wall and the co-operating scraper mechanism of the agglomeration drum in Figure 1 shows.

709841/0894

27H380

Agglomeration drum:

Since the critical features of the agglomeration drum according to the invention the shape of the inner wall and the interaction of this inner wall with the scraper device there is no need to detail the mechanism for rotating the drum and the scraper to describe. Incidentally, various mechanisms for rotating the drum are already known, e.g. U.S. Patent 3,316,585. In the preferred mode of operation, as shown in Figure 2, the respective directions of rotation are oppositely directed, albeit the direction and speed of rotation of the drum and the scraper mechanism also depending on the materials, which can be inserted into the drum, fixed or variable.

Annular ribs;

The inner wall 12 is provided with a plurality of annular ribs 16 which are preferably spaced at regular intervals along the length of the drum 10. The ribs 16 are steel rings or the like that are welded or otherwise attached to the inner wall of the drum. These rings act as a dam to retard the movement of the smaller undersized agglomerates in continuous operation from the " ⁿ feed end" to the "discharge end ^{11 of} the drum and to contact between the larger and smaller agglomerates that are formed limit. Although FIG. 1 shows that the ribs 16 are uniformly

709841/0894

27U380

long the drum are spaced, but can both the number and the spacing of the ribs can be varied.

Scraper Composition:

The doctor assembly 14 includes a rotating doctor shaft 18 supported in bearings 20 for rotating independently of the rotation of the drum, and two sets of doctor blades 22, 24 that are long and short. The doctor blades 22 and 24 are along the length of the shaft 18 attached and arranged in a plurality of rows. Four rows at right angles to each other are typical. Further possible arrangements are described under the heading "Modifications of the Preferred Embodiment". The majority of the blades in each row are of the longer type and are referred to as 22. You've done it "X" in Figures 2, 3 and 4 indicated length. Likewise, the shorter blades, indicated as 24, have a length indicated by "Y". The longer blades 22 are arranged along the shaft 18 in such a way as to that the entire inner wall 12 of the drum 10 between the ribs 16 is scraped off. Any of the longer blades can cover a separate inner wall surface. However, other possible arrangements will be described later. The shorter ones Blades are arranged to scrape the top surface of the ribs 16.

Modifications of the Preferred Embodiment Annular ribs;

As an alternative to the use of permanently attached

709841/0894

27U380

the ribs attached to the wall can be seen from the sticky mass, which is formed by intimate mixing of the heated coal, the charcoal and optionally the pitch on dam the inner wall along preselected annular paths around the inner wall. Such ways would coincide with the location of the shorter doctor blades. If one allows such a build-up around the inner wall, then the maximum effective depth of such retention ribs is determined by the difference in length between the long and short blades, i.e. limited by the factor (X - Y).

For example, if a longer dwell time is required To provide the smaller growing agglomerates, then the longer doctor blades 22 can be replaced by the shorter ones Scraper blades 24 are replaced, whereby a build-up of the agglomeration mass at the location of the replaced blades is permitted.

Scraper Composition:

The blades 22 and 24 may be arranged in rows so that the rotation by a given blade scraped area can overlap the scraped area of another blade of the same length. The blades but can also work together with another blade one after the other to create a common area of the inner wall scrape off. Finally, the rows of doctor blades can spiral around shaft 18 as an alternative be arranged to the parallel arrangement shown in Figure 1.

709841/0894

-7 (/ 27U380

Preferred implementation of the invention:

The input to the drum primary components are (1) particulate coal, which has just been preheated to a temperature below its softening temperature, (2) finely divided charcoal, which has been preheated to a temperature of 538-649 ⁰ C, and (3) optionally a pitch binder. While the quality of the charcoal generally determines the relative amounts of the ingredients added to the agglomeration barrel, typically the weight amounts used are 35 to 50 percent particulate charcoal, 50 to 65 percent charcoal and up to 1096 pitch. As a result of the preheating, tar is released from the mixture within the drum and the mixture becomes a loosely cohesive plastic and sticky mass. Part of this plastic sticky mass begins to adhere to the surface of the inner wall of the rotating drum. In order to maintain a uniform layer of the sticky mass between the annular ribs of the rotating drum, a scraper device of the type constructed in accordance with the invention is used. As a result of the drum action exerted by the rotating drum and the continuous removal of parts of this layer by a scraper device, these parts of the plastic particles grow together to form even larger agglomerates. These agglomerates continue to grow until the tar released from the mixture (including the pitch binder when added as an ingredient) loses its plasticity, with the result that the agglomerates become rigid and growth ceases. The point in time at which this plasticity is lost

709841/0894

- 27U380

depends on the type of coal and the molding temperature. For most coking coals or coal mixtures the time to loss of plasticity is about 10 minutes on average at a molding temperature of about 438 ° C, with higher molding temperatures correspondingly result in shorter periods of time.

The following describes how the scraper mechanism works to ensure: (a) a reasonable dwell time within the Agglomerating drum for sufficient agglomerate growth and (b) limiting sticking or Accumulation of the components on the inner wall to a desired depth.

The longer doctor blades 22, which work together with either doctor blades of the same or a different series, are arranged around the scraper shaft 18 so that they have the entire inner wall of the drum between adjacent Cover ribs 16. The shorter doctor blades 24 go across the ribs 16 by the rib height equal to the difference between the respective lengths of the doctor blades, i.e., the relationship expressed as (X-Y). In practice, the smaller agglomerates tend to settle immediately between such ribs as a result of the drum action, while the larger agglomerates tend to move over the ribs.

The agglomeration can be carried out continuously or batchwise. In continuous operation, the larger agglomerates have a lower tumbling effect

709841/0894

27U380

exposed than the smaller agglomerates as they pass through the drum, the slight angle (1 up to 2 ° γοη the horizontal) of the agglomeration drum descending from the loading end to the discharge end.

Finally, adequate rib depth must be provided in order to control the period during which the larger agglomerates are in contact with the smaller agglomerates. Otherwise the larger agglomerates would be tend to eat up or ingest the smaller agglomerates. With regard to an effective effect the optimal rib depth is a function of the combination of the agglomeration shape and the operating factors, which include the drum size and the bed depth of the Möllers.

Based on experience with agglomeration drums, the depth of the shallow bed should be about 20% of the drum diameter. As the drum rotates, the batch of growing agglomerates tends to spread out to form a concave surface (Figure 2), effectively reducing the bed depth to perhaps close to 0% of the drum diameter. Based on this optimal bed depth, the depth of the ribs should be about 4 to 12% of the drum diameter. Thus, a specific value for the factor (X - Y) can be determined for a drum with a given diameter.

Once the particles have merged and grown together into agglomerates (their predominant

709841/0894

Size falls within a narrow range), then the agglomerates are removed from the rotating drum. In continuous operation, additional agglomerates are removed at the same time as the agglomerates that have already formed are removed finely divided carbonaceous material is regularly introduced into the rotating drum for the purpose of education and training Repeating growth process.

Control of agglomerate size agreement:

The effectiveness of the preferred mode of operation was demonstrated as follows. To control the effectiveness of the ribs Controlling agglomerate size correspondence within a narrow range has become a batch guided agglomeration investigation without the use of a scraper mechanism, but with variations of the internal inpatient facilities.

The agglomeration tests of this study were performed in a 91.4-4 cm diameter drum as follows carried out:

a) With four rows of rakes attached to the inside wall of the drum,

b) with five annular ribs with a radial depth of 10.16 cm, which are evenly spaced along were arranged on the inner wall of the drum,

c) without any internal facilities, i.e. without Raking or ribs.

7098A1 / 0894

<! 7U380

The results of the size distribution studies (Table I) showed that the control of the formation of large agglomerates with annular ribs was better than with rakes or no internal facilities.

Table I.
Comparison of the size distribution control

Interior facilities average-average

liche mean borrowed size, cm, χ deviation,

cm, ö

a) Rows of rakes 3.51 1.68

b) annular ribs 2.21 1.40

c) without rakes or ribs 4.83 2.64

The average mean size is determined as the screen size over which 50% by weight of the agglomerates formed go out.

The average size deviation is given by the difference between the mean size and the screen size that about the size of either 15.9 or 84.1 wt. S-S of the formed Agglomerates, determined i.e. 50% - 34,196.

Using (6) as a measure of the size distribution of the agglomerates, the following is found: (1) without internal stationary devices, the agglomerate size distribution was quite large, and (2) with the annular ribs the agglomerate size distribution was smaller than with the Rakes and considerably smaller than when stationary facilities are not used.

709841/0894

2VH380

The individual values from which Table I is derived are listed in Table II. Each test was approximately equal proportions of Kayford charcoal and charcoal are used. No pitch injection was used. With 45.4 kg of load on each pass, the nominal bed depth was 19.1 cm. The drum speed was constant 18 rpm in all tests. The formation temperature was fairly constant, varying between about 417 and 432 ° C.

709841/0894

- 2VU380

Table II Agglomeration Tests

a) Rows of rakes:

attempt 1 U 47.3 2 Charge composition, wt 52.7 money 49.0 recycled charcoal 25th 51.0 Educational conditions: 427 Education time, min 320 25th Formation ^{temperature, 0} C (at
5 min) 606 423 Preheating temperature of the
Coal, ⁰ C 322 Preheating temperature of the
Charcoal, ⁸ C 0.0 603 Coke pellet size distribution,% by weight: 0.0 -12.7 cm + 10.2 cm 7.9 0.0 -10.2 cm + 7.6 cm 16.9 0.0 - 7.6 cm + 5.1 cm 32.4 23.5 -5.1 cm + 3.8 cm 11.4 35.2 - 3.8 cm + 2.54 cm 31.4 26.3 - 2.54 cm + 1.9 cm 60.7 8.0 - 1.9 cm 2.92 6.0 - 5.1 cm + 1.9 cm 1.83 69.5 x, medium size, cm 4.06 6, size deviation, cm 1.52

709841/0894

Z-7U380

Continuation of Table II b) Annular ribs:

Experiment 3 4 5 6 7

Composition of the charge, weight-96:

Coal 49.9 49.0 49.8 49.9 49.9

recycled charcoal 50.1 51.0 50.2 50.1 50.1

Educational conditions:

Education time, min 25 25 25 25 25

Educational tennerature,

⁰ C (at 5 min) 417 432 419 421 421

Preheat temperature of coal, oc 322 319 321 322 321

Charcoal preheating temperature, ⁰ C 604 604 604 604 604

Coke pellet size distribution,

-12.7 cm +10.2 cm 12.8 0.0 0.0 0.0 0.0

-10.2 cm + 7.6 cm 2.4 0.0 0.0 0.0 0.0

- 7.6 cm + 5.1 cm 21.7 3.4 4.1 4.3 0.4

- 5.1 cm + 3.8 cm 18.5 6.4 13.0 9.1 3.8

- 3.8 cm + 2.54 cm 21.7 14.2 26.8 24.9 14.1

- 2.54 cm + 1.9 cm 11.3 15.3 18.0 19.0 15.5

- 1.9 cm 11.6 60.7 38.1 42.7 66.2

- 5.1 cm + 1.9 cm 51.5 35.9 57.8 53.0 33.4 5c, medium size, cm 4.19 1.27 2.29 2.03 1.27 o ", size deviation, cm 1.02 1.91 0.76 1.78 1.52

709841/0894

27U380

Continuation of Table II c) without raking or ribs:

attempt 8th 9 0 10 11 Composition of the charge,
% By weight: 0 money 49.7 50, 50.0 49.7 recycled charcoal 50.3 50, 50.0 50.3 Educational conditions: Education time, min 25th 25th 25th 25th Formation temperature ^{, 0 C}
(at 5 min) 419 420 421 418 Preheating temperature
of coal, ⁰ C 321 322 322 324 Preheating temperature
the charcoal, oc 604 604 0 604 607 Coke pellet size distribution,
% By weight : 7th -12.7 cm + 10.2 cm 48.8 0, 2 0.0 0.0 -10.2 cm + 7.6 cm 13.1 1, 0 3.5 2.9 - 7.6 cm + 5.1 cm 7.6 5, 6th 34.0 14.8 - 5.1 cm + 3.8 cm 9.5 13, 3 30.0 24.5 - 3.8 cm + 2.54 cm 10.3 17, 2 20.8 30.5 - 2.54 cm + 1.9 cm 3.2 25, 9 6.5 13.8 - 1.9 cm 7.5 37, 54 5.2 13.5 - 5.1 cm + 1.9 cm 23.0 55, 78 57.3 68.8 x, medium size, cm 8.64 8th, 4.44 3.68 O, size deviation, cm 6.10 1, 1.91 1.78

709841/0894

27U380

While the invention addresses the primary problem of If the person skilled in the art is employed to control the size distribution of the agglomerates, naturally he or she can also pay attention refer to other known concepts to obtain the particular agglomerate size desired. So tends e.g. the presence of rakes helps to reduce the formation of the larger agglomerates, thereby reducing the continuous Growth of smaller agglomerates is allowed. Other variables known to be affecting the agglomerate size of the coke formed are: the bed depth, the formation temperature, the extent of the Pitch addition and the coal concentration in the feed. This information results together with the application of the present invention, the production of agglomerates of constant size, which are suitable for technical purposes e.g. formed coke for blast furnaces in the steel industry.

709841/0894

Read more

Claims (8)

27H380 claims 1. Chunking device to control the size of carbonaceous materials and to form agglomerates therefrom, with a drum having an inner wall rotatable about a central axis of the drum and inlet and outlet means for introducing and removing the carbonaceous materials the agglomerates thereof, and a rotating shaft that extends into the drum and that of the Central axis of the drum is offset, characterized by a plurality of first doctor blades (22) of a given length which protrude from the shaft (18) and which are designed so that they are accumulated Scrape carbonaceous materials from the inner wall (12) of the drum when the drum and the shaft are rotated; and a plurality of second doctor blades (24) of shorter length extending from the Jump out wave. 2. Apparatus according to claim 1, characterized in that g e k e η η indicates that a plurality of annular ribs (16) are provided which are attached to the inner wall with each annular rib lying in the path of rotation of one or more of the second doctor blades. 3. Apparatus according to claim 1 or 2, characterized in that the annular ribs have a radial extent of about 4 to 12% of the diameter of the rotating drum. 709841/0894 ORIGINAL INSPECTED 2VU380 4. Device according to one of the preceding claims, characterized in that a plurality of bundles of the first and second doctor blades is available. 5. Apparatus according to claim 4, characterized in that the bundles along the length of the Drum are distributed parallel to the axis of the rotating shaft. 6. Apparatus according to claim 5, characterized in that the first and second doctor blades define spiral bundles around the rotating shaft. 7. Process for continuous piece-making of carbonaceous materials in an agglomeration drum, which rotates around a fixed axis and which has a loading end, an inner wall and a discharge end wherein the carbonaceous material introduced into the feed end is finely divided Contains coal particles and finely divided particles of a carbonaceous residue, with a layer of the finely divided particles are formed on the surface of the inner wall of the rotating drum during the treatment and wherein a portion of this layer is continuously removed to facilitate the transfer of the carbonaceous materials to initiate agglomerates with a preselected size to exit the discharge end of the drum, thereby characterized by ensuring that the majority of the agglomerates have a size within 709841/0894 - he - 3 27U380 of a narrow, preselected range, regulates the spreading time of the agglomerates that form within the drum in order to allow the smaller agglomerates to grow
of the preselected size, the relative
axial speed of the larger and smaller agglomerates through the drum is directly proportional to their size, and that the agglomerates formed from the
Discharge end of the drum removed while new
finely divided carbonaceous material continues into the feed end of the drum. 8. The method according to claim 7, characterized in that one determines the residence time of the agglomerates formed by spaced apart annular ribs which are provided on the inner wall of the drum, each rib with the
The axis of this drum is concentric. 9 · The method according to claim 8, characterized in that the contact between the larger and smaller agglomerates through the annular
Ribs limited. 709841/0894