FI67225B - FOERFARANDE FOER FRAMSTAELLNING AV KOKS - Google Patents

Description

f, ADVERTISEMENT PUBLICATION, πλλγ yasr · w ουutlaggningsskrift o / zzb C Patent granted 11 C2 1925 (45) Patent meddclat ^ ^ (51) K «j ^ / iM.a.3 C 10 B 57/04 FINLAND — FINLAND (21) 802372 (22) - AmBIwliniitH 29.07.80 (23) AMmpaivft — GHtighatadaf 29.07.80 (41) TilK frlktMkri - B «vtt iiwH || 30/1/82

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(32) (33X31) Pjnrdettr weilww- * | ifd prioriuc (71) Charbonnages de France, 9, Avenue Percier, 75008 Paris, France-France (FR) (72) Georges Prudhon, Forbach, Jack Verlaine, Douai, France (74) Ruska f. Co Oy (54) Process for the production of coke - Förfarande för framställning av koks

In the past, French patent 1,265,397 has proposed to improve the quality of coke from low-coking coal by increasing the density of the charge, not only by drying the mixture of coking coal, but also by other means to artificially increase the density, for example by agglomerating the dry mixture and gravity. mixture of ingredients. This method requires prior drying of the fine coal particles.

French Pat. No. 1,195,232 discloses a coking process in which wet coal powder is agglomerated using a press which produces agglomerates with a protruding edge which breaks irregularly as it exits the press, after which the mixture of agglomerates is crushed to a larger or smaller size. .

French patent publication 1 176 762 also discloses a method in which a part of the coal powder to be charged is agglomerated and the mixture of agglomerates obtained is charged together with at least the same amount by weight of unagglomerated coal powder.

2,67225 The object of the present invention is to provide an improved process of the type described in French Patent 1,265,397, according to which it is possible to either increase the amount of poorly coking coal which can be combined with a mixture or to improve the mechanical strength of coke. The method is also available for charging wet coal powder and preheated coal powder.

In the case of moist coal powder, according to a further object of the invention, coke for the iron and steel industry can be obtained from mixtures containing poorly coking coal without recourse to preheating technology.

This object for the production of coke is achieved by a process characterized by the preparation of a mixture of coal powder with a particle size of 80% of less than about 2 mm, this mixture containing uncoking or poorly coking coal. having an expansion index of not more than 5%, that during the preparation of the mixture at least some of the constituents in the form of coal powder are agglomerated in a press after the addition of tars or bitumen with a KS point of about 70-85 ° C to combine or recombine the mixture into the chamber and that during the preparation of the mixture at least some of the agglomerates are re-crushed to a particle size such that 50% have dimensions smaller than about 3 ~ 5 mm.

The smallest possible amount of binder, namely at least 5%, is considered to be very advantageous in order to ensure that the agglomerates maintain their cohesiveness during processing. In the description that follows, the terms crushing (and re-crushing) refer to any method of fragmentation in which the material to be fragmented is subjected to compressive or impact loads resulting in an adjustable particle size, as is known per se. As a result, the sizes of the re-crushed particles are distributed over a very wide regular granularity, which allows the coke oven to be filled to the best possible extent. In addition, this method of adjustable re-crushing 5 67225 makes it possible to stabilize the charge density by eliminating large local variations in the charge density, which can occur in the case of agglomerates and which can be detrimental to the quality of the coke.

Thanks to re-crushing, the agglomerates are surprisingly inexpensive. In fact, it is conceivable that re-crushing, the compact structure obtained by "agglomeration by disposal", eliminates the advantages in feed tightness which are the main purpose of earlier patents, in particular French patent 1 265 397 and other later patents. Although no scientific explanation has been given, re-crushing , which results in the fragmentation of the concentrated mixture, provides beneficial effects that not only preserve the quality of the coke, but actually improve it.

In fact, it has been found that the reduction in batch density resulting from re-crushing of agglomerates surprisingly provides a further improvement in the mechanical strength of the resulting coke.

The teaching of the present invention is also very surprising compared to the teachings of French Patent 2,121,021, which shows that agglomeration together with coal tar rods with a softening point of 40-100 ° 0 does not solve the main problem of poorly coking coal. This is because this patent proposes agglomeration with a bituminous material having a softening point of 100-400 ° C. However, apart from the fact that this requires a special material which is expensive to obtain, the process requires a complex heat treatment of coal, the coking properties of which must be improved.

Depending on the number of possible variations of this invention, the agglomerates may be re-crushed before or after incorporation or re-incorporation into the mixture, and the entire amount of at least one component of the non-coking or poorly coking components may be agglomerated before incorporation into the mixture. It is also possible to mix all the ingredients together, agglomerate the whole mixture and crush it again in its entirety.

In one embodiment, the agglomerates are re-crushed to the original particle size of the coal powder.

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According to another embodiment, the coal powder to be agglomerated is agglomerated in a moist state at 8-10%, after which the mixture is gravity charged.

In one embodiment, all ingredients are mixed together, the entire mixture is preheated to a temperature above 100 ° C, and at least a portion of the mixture is agglomerated and then crushed, having previously been recombined. It is also possible to agglomerate the entire preheated mixture before re-crushing at least part or even the entire mixture.

In one embodiment, the wet agglomerates are re-crushed, mixed with non-agglomerated coal powder, and then an amount of light oil on the order of 0.1 to 0.5% is combined into the mixture for charging.

Other features and advantages of the invention will become apparent from the following description of typical embodiments of the method of the invention.

The coke obtained in the following description is known by the standard designations MICUM and / or IRSID, which are well known to those skilled in the art. However, the following recalls what these markings mean.

The mechanical strength of coke is usually determined by MICUM testing (French standard NF M03020) and IRSID testing (French standard NF M03023). These tests involve rotating a sample of coke in a drum with a horizontal axis and measuring the amount of coke to be processed, whether or not it passes through sieves of a given mesh size. The following is obtained from testing: coke size greater than 40 mm. This is an index Μ,. ^ Or I ^ q which is higher the higher the strength of the coke against fragmentation or compression, the smaller the size of the coke. This is or I ^ q »which is lower, the better the abrasion resistance or cohesiveness of the coke, the size of the coke is greater than 20 mm. This is the I ^ Q index, which increases with the cohesiveness of the coke.

The desired values for these different markings are as follows: 67225 5 M4o> 75-80 Μιο <7- 9 -> 40 I20> 76-78 I10 «20-22

To make the examples easier to understand, poorly coking or non-coking coal is marked with *.

The tests on which the following examples are based were all performed with coal tar KS 79, MV 60 or petroleum bitumen KS 72, MV 71, the KS point being given in ° C in the Kraemer-Sarncw test described in Manuel du Laboratoire routier , In the collection of the Laboratoire central des Ponts et Chaussees (page 277, published by Dunod), and MV indicates the level of volatile matter, dry ash, free from bases (daf), expressed as a percentage.

Examples I-III

First, experiments were performed comprising the first three examples in which poorly or slightly coking ingredients were agglomerated in a twin-roll press in the presence of 8% coal tar pitch to obtain 40 g of agglomerates, re-crushed the agglomerates thus obtained, and re-crushed coal powder. in the form of crushed coal powder, after which the resulting mixture was charged to a coke oven. Comparative experiments were performed all the time, first on all agglomerates as a whole, as is already known, then on re-crushed agglomerates, as mentioned above. In these first three examples, eight coal marked A-H were used, with the coal marked F, G and H having poor coking properties or none at all.

6,67225

Coal reference MV index (daf) Expansion index A 20.8 5 1/2 B 20.9 7 1/2 C 19-8 8 1/2 D 20.1 9 E 2 * 1.0 8 1/2 F * 30.5 1 1/2 G * 36 3 ; H * 6 0

The results of the coking tests are summarized in Table 1.

table 1

Example - * · __I__II ___ III_

Charged 25% k '/ crushed 20 Z b | / crushed 32% B J / crushed mixture 40% B coal- 20 Z E) Coal- 21% C I J coal composition 10 Z C powder] powder 7 Z D | λ powder (.80% <2 mm [δ0% <2 mm 10% Ej (80% <2 mm 25 Z F (agglomerated) 60% G (agglomerated) 30% H (agglomerated)

Reference size.bri- re size.bri- re size.bri- re chains crushed chains crushed chains crushed (known briquettes (known briquettes (known briquettes method) (invention) method) (invention) method) (invention) 84.2% <2 mm 80% <2 mm 80% <2 non

Coke quality coke MICUM M 40 81.3 86.2 use- 80.2 80.4 89.2 invalid

Index M10 8.1 6.6 9.6 9.3 6.6 In these three examples I-III, the process according to the invention provides a very significant improvement in the values of the mechanical strength of coke compared to the known processes.

Example IV

A mixture of coal containing a high concentration of poorly coking coal was charged by known charging methods and by the method of this invention, in which the wet charge was completely agglomerated into briquettes using a conventional two-67225 roll press, in the presence of 6% petroleum bitumen. was crushed again.

The main features of the coal used are given below.

Coal MV Index Expansion- Expansion-? » International reference d.a.f. code between the index I * 34.0 3 -20 621 J 23-6 9 +36 433 K 30.0 7 1/2 +46 533

The main results of the coking tests are shown in Table 2.

Table 2 __Known batching methods_ Method according to the invention from coal powder 100% Mixed pa- 100% by size. 86.1% <2mm, 50% size. Manufacture crushed nos coal briquettes briquettes, 50% new technology from coal powder to coal crushed briquette powder 83.2% <2mm, i.e. from powder, tea, 53.4% <5 mm, 85.1% < 2mm 37.2% coal 82.1% <2mm 36% <2 mm powder, 62.8% briquettes ___

Composition of the mixture 'j I% 60 60 60 65 / · J% 20 20 20 17.5 _J K% __ 20__20__20 ___ 1Λ5 ___

Coke \> 80 mm% 13.1 10.8 5.4 6.1 particle size \> 40 mm% 80.0 69.8 65.0 69.5 _ '> 20 mm% __ 85.7__96.7 94.5 _93.8_ MICUM \ M40 76.4 68.9 70.1 80.3 grades 1 M10 12.6_ 8.4__8. 3__7.7_ IRSID) 140 45.8 32.7 34.7 49.0 grades f 120 70.8 74.8 76.0 76.8 _> IIP_28.2_21.7 21.6_21.0 ____

The values of mechanical strength for coke obtained by the process of the present invention are generally better than the corresponding values for coke produced by known batching methods, despite the fact that the proportion of poorly coking coal in the mixture is higher in the process according to the invention.

Examples V and VI

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A mixture of coal containing a high concentration of poorly coking coal was charged by a variety of procedures, including the procedure of this invention in which the wet charge was completely agglomerated in a conventional twin roll press in the presence of 6% petroleum bitumen and all agglomerates were crushed again. input to the coke oven chamber. In Example VI, only a portion of the agglomerates were re-crushed to a degree of granularity similar to the fineness of the initially crushed coal powder.

The same coal as in Example IV was used. The granulometric conditions for each column of Table 3 were as follows, corresponding to the manufacturing methods mentioned here: 100% crushed coal powder: 85.1% <2 mm mixed batch: 83.2% <2 mm 100% whole briquettes: 82.1% <2 mm method according to the invention: 83.3% <2 mm

Particle size of re-crushed briquettes: 56.3% <5 mm 37.9% <2 mm 9H.6% <5 mm 80% <2 mm

Table 3 shows the test results.

9,67225

Table 3

Known batching methods Method according to the invention ____ Example V Example VI_

Manufacturing * · 100% Mixed 100% 100% ^ 507 size, briquettes, crushed batch whole re \ 50% re-crushed coal- 37.2% stone briquettes crushed paved briquettes powder coal powder briquettes hetta 62.87 bri- ____chains ____ I% 60 60 60 65 65 J% 20 20 20 17.5 17.5 K 1__20__20__20__17.5 17.5_

Coke f> 80mm7 13.1 10.8 5.A IA.8 10.0 j> A0mm% 80.0 69.8 65.0 77.3 75.5 _ (> 20mm% 85.7__96.7__9A.5__9A.0__96.1_ MICUM-) MAO 76.A 68.9 70.1 80.8 75.3 grades) M10 12.6 8.A 8.3 9.5 8.9 IRSID-λ ΙΑ0 A5.8 32.7 3A.7 50.3 A7.8

grades! 120 70.8 7A.8 76.0 76.9 76.A

) 110 28.2 21.7 21.6 20.8 21.8

The above results demonstrate the advantages of the process of Example V of the invention, in which the best properties of coke are obtained in the presence of a high concentration of flambant gras, while acceptable results are obtained in Example VI despite the high concentration of lean coal I. In any case, the process better than what is achieved by known methods.

Example VII

An embodiment of the method of the present invention will now be described in which the entire coal mixture is agglomerated using a conventional twin-roll press and in which all the agglomerates are re-crushed to the same particle size as the initially crushed coal powder before being charged to the coke oven. The experiments were performed with a mixture containing a certain proportion of poorly coking coal of the "flambant gra§" type, which coal does not give coke of acceptable quality by known batching methods. The tests were performed under the operating conditions previously described in connection with the first examples.

10 67225 The characteristics of the coal used were as follows:

Carbon- Quality MV index Swelling- Expansion International reference index between _________________code I * '' flammable 34.0 3 -20,621 grass “J” grass ä 23.6 9 +36 h33 coke "L" grass ä 28.5 8 1/2 + 13¾ 534 coke "K" grass 30.0 7 1/2 + 46 533 coke "

The particle sizes were as follows for each column of Table 4 corresponding to the batch procedures presented herein:

Table 4

25% I

Mixing formula 25% L

__50% K__ __Known betting methods_ Invention

Input- $ 100 mixed pa- $ 100 10W method crushed chips $ 70 stone size. uuaeiieen vihii li powder coal powder, briquettes ^ $ 30 briquettes £ a ... ri e tej a

Coke f> 80mm $ 42.5 36.9 17 * 4 38.8 j> 40mm $ 91.5 91.7 86.8 91.3 _ (> 20mm $ __ 95.2__97-4__96.6__95.5 MICUM-} M40 74.9 73.6 74.7 73-3 grades] M10 10.6 8.9 9- 0 8.7 IRSID- ^ 140 40.2 41.9 37.0 46.0 grades> 120 67-4 71.2 70.9 73-9 _ IIP_29.6_ 25.9_25.9_23.5 The use of the method of this invention results in an overall improvement in the mechanical strength of the coke, i.e. by achieving a uniform coke the method according to the invention makes it possible to increase the proportion of poorly coking coal of the "flambant grar" type in the coal mixture.

11 67225

In Examples I-VII, all inputs were gravity inputs. The operation was performed using known methods.

According to Examples IV-VII, moist coal was treated, and the water content of the batches in the process according to the invention varied between 6% and 7.5% ·

Examples VIII and IX

The coking tests described in Examples IV and V were supplemented by an experiment performed using an embodiment of the process of the invention in which the mixture was preheated to 150 ° C, then agglomerated with 6% coal tar pitch and 50% of the agglomerates were re-crushed to a coarse particle size. 50% passed through a 2 mm sieve (Example VIII). In Example IX, the coal mixture was preheated, then agglomerated in the presence of 6% coal tar pitch, using a twin roll press, and 50% of the agglomerates were re-crushed to approximately the particle size of the initially used coal powder, characterized by about 80% passing through a 2 mm screen.

The particle size test conditions were as shown in each column of Table 5, corresponding to the manufacturing methods: Starting coal powder: 100% preheated coal powder 90.7% 2 mm wet charge 85.2% 2 mm 100% wet briquettes 82.1% 2 mm Example VIII 82.5% 2 mm Example IX 86.8% 2 mm

Re-crushed briquettes: Example VIII: 5 ^ .6% 5 mm 38.2 5? 2 mm Example IX: 91-7% 5 mm 75.8% 2 mm

Batch temperatures: £ 100 preheated coal powder: 245 ° 0

Example VIII: 119 ° C

Example IX: 88 ° C

The results are shown in Table 5-67225

Table 5

Method according to the invention

Reference Known betting methods „.

_____Example VIII Example IX

100% Moist input 100% humid- 50% preheat- 50% preheat-

Manufacturing preheated Γ37.2% coal total briquetted bri- method briquettes · briquettes, chains, coal (62.8% briquettes 50% re 50% re-powder crushed crushed _____briquettes and briquettes I *% 60 60 60 65 65 J% 20 20 20 17.5 17.5 K% __ 20__20__20 ___ 17.5 17.5

Coke C> 80mm% 10.2 10.8 5.4 7.3 6.9 \> 40mm% 79.5 69.8 65.0 72.2 71.6 _v> 20mm% 92.5__96.7__94.5__94.6_ 95.4 MICUM-) M40 78.1 68.9 70.1 77.8 77.9 grades) M10 9.5 8.4 8.3 8.1 6.1 IRS1D λ 140 50.1 32.7 34.7 not measured 51.6 grades V 120 76.5 74.8 76.0 80.0 J IIP 22.1 21.7_21.6 _ 18.3

Example VIII of the process according to the invention gives the best compromise in that it produces coke with both good resistance to fragmentation (Μ4θ) and good abrasion resistance (M10). The results of Example IX clearly demonstrate the advantages of the process of the invention in terms of the mechanical properties of coke. In particular, the coke produced has very good abrasion resistance, despite the fact that the input contains a large proportion of coal, which is considered to be poorly coking.

Example X

A mixture containing a very large amount of poorly coking coal of the "flamrrf.-. Bant gras" type was charged using known charging methods and the method of the present invention, in which the entire mixture of coal preheated to 150 ° C was agglomerated at this temperature. 8% coal tar pitch was present and in which the agglomerates were coarsely crushed back to a particle size characterized by 48.9% passing through a 2 mm sieve (APNOR module No 35) ·

The initial particle size test conditions for coal powder were as follows, for each of the methods shown in Table 6, respectively: 2: 67225 preheated coal powder: 82. t Γ <I mm wet briquettes: 79.8% <2 nnri preheated briquettes: 83-2 7 »<2 mm reheated briquettes: 83 -2 t <2 mm

The experiments were performed under the conditions described in connection with Example V and the same coal was used.

Table 6 shows the results of the coking tests.

Table 6 m ^ According to the invention

Knocking Known betting methods ___nen mene t.e ima_

Preheated from 1007 to 1007 from 1007 to re-Fanostus-crushed moist preheated crushed method coal powder briquettes net briquettes ______chains_______

Charging temperature ____________ I% 80 80 80 80 J% 10 10 10 10 K% _ 10__10__10____10_____

Coke 80mm £ 9-8 9-5 7.9 7-2 40mm% 72.9 64.7 63-9 69.7 _20mm% __ 87.0__94.3__95.3 __94.2_ MICUM- M40 75-4 68.1 67.6 71.2 grades M10 14.6 9-2 8.8 8.5 IRSID- 140 32.7 36.7 42.0 grades 120 no 72.9 73-4 75.1 __IIP_assigned 2 4.5 ___ 24.3__22.6 _

With the process according to the invention, it is only possible to obtain coke of acceptable quality for a blast furnace from a mixture containing 80% of "flambant-gras" type poorly coking coal.

Example XI

In this example, a charge containing ICC% Demi-gras, a type of poorly coking coal combined with 8% coal tar pitch was charged. In the absence of small, this coal does not actually combine at all and produces powdery coke suitable for all uses. In the presence of tars, this coal produces Combined Coke quite well by known batching methods, and it is found that high quality coke can be obtained under these conditions using the method of this invention.

In the process of this invention, the coal was preheated to 150 ° C, agglomerated in the hot state in the presence of 8% tar pitch, using a conventional twin roll press, and then re-crushed in a hammer mill to a fineness characterized by stallion passing through a 2 mm screen (AFNOR module No 35 ).

The characteristics of this coal (reference M) are as follows:

Quality MV Index Expansion- Expansion International d.a.f. index% between _____code "Demi-gras" 17.0 3 -18 321

The starting conditions for the coal powder starting fraction were as follows for each method shown in Table 7: 100% moist coal powder 88.7% <2 mm 100% preheated coal powder 9 ^ -7% <2 mm 100% preheated briquettes 88.7% <2 mm 100% recrushed briquettes 95% <2 mm

Table 7 shows the results of coking tests in a so-called 400 kg furnace obtained with a mixture containing 92% coal M and 8% tar pitch.

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Table 7

Reference__Known Batching Methods__Invention 100 # Moist 100 # Pre-100 # Whole 100 # Re-Manufacture of Coal-Crushed Pre-Crushed Imit Coal-Deheated Pre-Heated Powder Briquettes and Briquettes

Ejikeatrms-, 250 ° C 250 ° C 16 ° C

temperatures _______

Charging / o 8 o o temperature ___________

Coke (> 80mm # 49.0 44.4 22.2 35-3)> 40mm # 86.1 87-4 78.6 86.1 _v> 20mm #__ 91.3__92.8 90.8__91-5 MICUM-) M40 80.2 80.8 73-6 82.0 grades) M10 9-7 9-4 10.6 8.9 IRSID-1 I40 48.5 46.4 38.4 58.0 grades> 120 68.0 68.6 67-3 75.4 _J IIP_30.0 30.2_29.2 23.2 The advantage of the method according to the present invention is mainly in the improved cohesiveness of coke, which is very remarkable in this example.

Thus, in various embodiments of the invention, the following steps have been used sequentially:

Agglomeration of a portion of a coal powder mixture and re-crushing of agglomerates (Examples I-III), agglomeration of a wet crushed coal powder mixture and re-crushing of a portion of agglomerates to a particle size that is coarser than a fraction of agglomerated coal powder re-crushing of agglomerates to a particle size coarser than the particle size of the starting coal powder (Example V), agglomeration of a wet base coal powder mixture and re-crushing of a portion of agglomerates to the same particle size as the originally crushed coal powder (example VI), crushed coal powder (Example VII), agglomeration of a mixture of preheated crushed coal powders and re-crushing of a portion of the agglomerates to a particle size that is coarser than initially crushed coal

Claims (13)

A process for producing coke, comprising preparing a mixture comprising a coal powder having a particle size such that 80 5 ?: 11a is less than about 2 mm in size, wherein the mixture comprises uncokeed or poorly coking coal having an expansion index of not more than more than 5, wherein during the preparation of the mixture at least some of the ingredients in powder form are agglomerated in a press after the addition of tars or bitumen having a KS point of about 70-85 ° C to combine or recombine them, and the resulting mixture is charged to a coke oven chamber; characterized in that during the preparation of the mixture, at least some of the agglomerates are re-crushed to a particle size such that 50% have dimensions smaller than about 3 to 5 mm. Process according to Claim 1, characterized in that the component to be agglomerated is agglomerated after the addition of at least 5% of tar pitch or bitumen. Process according to Claim 1, characterized in that the agglomerates are re-crushed before they are combined or recombined into a mixture. Process according to Claim 1, characterized in that the agglomerates are re-crushed after they have been combined or recombined into the mixture. Process according to one of the preceding claims, characterized in that the total amount of at least one non-coke or poorly coke component is agglomerated before incorporation into the mixture. 67225 Process according to Claim 1, characterized in that all the ingredients are mixed together and the whole mixture is agglomerated and the whole is crushed again. Method according to one of the preceding claims, characterized in that the re-crushing is carried out to give a particle size which is substantially the same as the particle size of the original coal powder. Process according to one of the preceding claims, characterized in that the powder to be agglomerated is agglomerated in a moist state and contains up to about 8 to 10% of water. Method according to one of the preceding claims, characterized in that the mixture is charged by gravity. Process according to one of Claims 1 to 7, characterized in that all the ingredients are mixed together, the whole mixture is preheated to a temperature above 100 ° C and at least part of it is agglomerated and then crushed again before recombining. Process according to Claim 10, characterized in that the entire preheated mixture is agglomerated before it is at least partially crushed again. Process according to one of the preceding claims, characterized in that all the agglomerates are crushed again. Process according to Claim 8, characterized in that the wet agglomerates are re-crushed, then mixed with the non-agglomerated moist powder and a certain amount of 0.1 to 0.5% of light oil is combined with the mixture to be charged. 67225