DE1102030B - Resetting agent of the binding pitch for the production of carbon molded bodies - Google Patents

Description

GERMAN

To produce shaped coal bodies, the petroleum and / or coal tar pitch coke used as dry material is mixed with a specific grain composition with a binder, preferably coal tar pitch, and shaped in the usual way. Thereafter, the carbon article is subjected to a furnace firing at about 1000 ⁰ C and optionally a graphitizing process at temperatures over 2000 ⁰ C. During the furnace fire, the binding pitch cokes to form a coke skeleton, which cementes the individual coke grains and gives the shaped body a corresponding strength. Since this generally depends on the binder coke yield, the preferred binder in the charcoal industry is pitch with the highest possible softening point. However, there are technological limits to the use of the pitch, since a pitch with a high softening point requires a higher processing temperature during mixing and pressing. To overcome these difficulties, pitches with a higher softening point are reset to a lower one.

Coal tar or higher coal tar fractions have so far been used as so-called restoring agents oily consistency used. However, these known restoring means have the disadvantage that the Binder coke yield, based on the binding pitch, practically not changed because the restoring agents themselves deliver little or no coke, d. H. the binder through those used to reset Substances are only diluted, so to speak. However, this means a deterioration in the quality of the molded carbon bodies obtained with regard to density, strength and pore volume, since the shaped body is then when fired a larger amount of gas escapes than when firing moldings to which no restoring agent has been added is, is the case. In addition, it has been shown that the restoring means previously used as a result of their in part high viscosity cause only a slight reduction in the softening point.

It has now been found that the disadvantages of the known restoring means can be avoided, if according to the invention organic compounds which are soluble in the binding pitch and which have one or more active double or Contain triple bonds, individually or in a mixture as a restoring agent for the production of Charcoal moldings are used.

According to the invention, organic compounds have proven to be particularly suitable for this purpose which have a or several C = C -, CsC - (e.g. unsaturated hydrocarbons, vinyl or acetylene derivatives), C = O - (e.g. ketone, aldehydes, quinones), C = NH- (ζ. B. Imines), C = N - (ζ. Β. Nitriles), C = S- (THoverbüidungen, z. B. xanthates) or N = N bonds (azo compounds).

Resetting means of the binding pitch
for the production of carbon moldings

Applicant:

Farbwerke Hoechst Aktiengesellschaft

formerly Master Lucius & Brüning,

Frankfurt / M., Brüningstr. 45

Dr. Otto Peter, Hofheim (Taunus),
and Dipl.-Chem. Dr. Helmut Reckhard,

Frankfurt / M.-Griesheim,
have been named as inventors

When using the suggested connections

z5 as a restoring agent results from the same additional amount not only a stronger lowering of the softening point of the binding pitch, but also one at the same time in some cases a considerable increase in the coke yield of the same compared to the restoring agents used hitherto. Figs. 1 and 2 show diagrams in which the relationship between the softening point and the coke yield a binding pitch from the additional amount of the restoring agents used hitherto and the restoring agents according to the invention is shown.

Here, on the ordinate in Fig. 1, the softening points determined according to Krämer-Sarnow are one Pitch used as binding agent in ° C and in Fig. 2 the coke yields determined according to Elektrokemisk of the same, based on the pitch used, and on the abscissa in each case the addition of restoring agent !!, in Applied weight percent.

From Fig. 1 it can be seen that the inventive use of phthalonitrile, azobenzene, Styrene or phenylacetylene as restoring agents significantly increase the softening points of the binding pitch than are reduced by the previously used tar oils, while Fig. 2 clearly shows that by the proposed restoring means at the same time the coke yield of the binding pitch is significantly improved.

In Table 1 are a number of according to the invention as

. Restoring agents listed organic compounds that are one or more active Have carbon-carbon compounds; in Table 2 those that contain one or more active carbon

109 529/619

Oxygen, and in Table 3 those that contain one or more active carbon-nitrogen compounds. The second column shows the addition of the specified restoring agent to the binding pitch in percent by weight, in the third column that to K ram er-Sarnow determined softening point and in the fourth column the coke yield of the determined according to Elektrokemisk Bindepeches indicated.

Table 1> C = C <and —C = C-

Addition to the binding pitch

Softening point ⁰ C

Coke yield

Propargyl alcohol CH- C - CH ₂ OH

Acenaphthylene

Dicyclopentadiene

Turpentine oil

α CH = CH ₂ CH = CH ₂

1,6-dimorpholinyl-hexadiia-2,4
CH,

Divinylbenzene

N '/ S-Chlorallyl-morphoHn
O

Methacrylic acid
Crotonic acid
Vinyl propionate
Dibutyhnaleinat

CH ₉ = C-COOH

CH ₃ -CH = CH-COOH C ₂ H ₅ -COO-CH = CH ₂ C ₄ H ₉ -COO-CH = CH-COO-C ₄ H ₉

1 ^ -dicyclohexanolyl-diacetylene

JtX \ ^>. j \ j ; ^ = v »f 'Ks; = ν *

OH

2-butylidene-cyclohexanone-l

10

10 10

10 10

10

10 10 10 10 10

10

49.5 (56)

45.5 (79)

43 (79)

48 (41.5)

27.5
46 (57)
(78) 46
55 (42)
(51) 43
54 (62)
(81.5) 50.5
57 (43.5)
(50) 40
50 (62)
(81.5) 48
54 (43.5)
(50) 37 (63.5) 48 (44.5) 40.5 (81) 56 (51) 65.5 (82) 57 (51)

59 (52)

45 (57) 44 (42) 40.5 (56) 50 (41.5) 27 (57) 46 (42) 27 (56) 43.5 (41.5) 79 (82) 55.5 (51)

57 (52)

Table 2> C = O

additive

to the binding pitch / o

Softening point

Coke yield

Acetylacetone succinimide

0 0

Il Il

H ₂ CC

Naphthalenedialdehyde

Benzil

Anthraquinone

Coumarin 2-allyloxyanthraquinone

Phenyl isocyanate

- O - C - 1 - C - H =

Table 3 C = N- or -C = N

29 (57)

55 (63.5) 53 (63.5)

44.5 (63.5)

57 (61)

43 (63.5) 56.5 (63.5)

52 (56)

46.5 (42)

47 (43.5) 57 (43.5)

50 (43.5)

51 (45)

47 (43.5)

55.5 (49.5)

44.5 (41.5)

N = C-CH ₂ -COOH additive
to the binding pitch Softening
Point
⁰ C (57)
(57) Coke yield (42)
(42) Cyanoacetic acid
Malononitrile C. 10
10 54
53 (57) 51
51 (42) Benzonitrile 10 30.5 (63.5) 49.5 (44) Adipic acid dinitrile N = C-CH ₂ -CH ₂ -CH ₂ -CH ₂ -C = N 10 31 (56) 49 (41.5) Phenyl isocyanate he-· 10 52 (78)
(78) 44.5 (50.5)
(50.5) Succinodinitrile
Benzalaniline N = C-
C ₆ H ₅ N 10
10 55
69 52
53.5 -CH ₂ -CH ₂ -C = N
= CH-C ₆ H ₅

Those in. The third and fourth columns in brackets The figures given indicate the values of the pure binding pitch without the addition of restoring agents.

Particularly noteworthy is the selectively dehydrating effect of the proposed restoring agents that act on it is based on the fact that they condense only part of the compounds present in the coal tar pitch in an oxidizing manner, z. B. fluorine, acenaphthenic, carbazole derivatives and other compounds with relatively easy mobility Hydrogen atoms while another part, ζ. Β. ίο Chrysene, pyrene, etc., cannot be dehydrated. Crucial for the effect of the invention Additives is therefore that, in addition to their solubility in the binding pitch, a lowering of the softening point causes, on the one hand, its dehydrating effect is great enough to make compounds of coal tar pitch to dehydrogenate with mobile hydrogen, but that on the other hand it leads to dehydrogenation on the aromatic core itself is insufficient. Through this selective dehydration it is achieved that on the After burning the binding coke from the pitch no change in its properties in practice, for example the thermal expansion

keeping the graphitability and hardness, despite an increase in. Binder coke yield can be determined. This is especially true for carbon moldings that are subjected to a subsequent graphitization process should, of great importance, as all previously proposed condensation agents to increase the Coke yields, such as. B. sulfur, metal oxides and chlorides, organic nitro and chlorine compounds, Oxygen and oxygen-releasing compounds, due to their strong oxidizing effect, those in the binding pitch dehydrate existing compounds so strongly that the resulting binding coke has a high coefficient of expansion and has a reduced ability to graphitize. In addition, for example when using nitro compounds and oxygen-releasing substances, such as. B. peroxides, larger amounts of water during dehydration, which deteriorates particularly in coal production the structure and thus also the strength of the molded body.

Compared to the known resetting means, the connections proposed according to the present invention thus have a number of considerable advantages. Thus, for example, when using the proposed compounds, the softening points of the binding pitch are reduced much more sharply than the previously used restoring agents with the same amount of restoring agent added, which is tantamount to a lowering of the dynamic viscosity, since the softening points determined according to Kramer Sarnow are the equivalent viscosity temperature for the viscosity of about 10 ⁷ cP is to be addressed. By lowering the viscosity of the binding pitch, either the temperature when mixing coal tar pitch coke and binding agent can be lowered or a binding pitch with a higher softening point can be used.

Another advantage of the proposed compounds is the increase in the binder coke yield, an improvement in the properties of the carbon molded bodies produced, such as an increase in the density, the Strength and lower pore volume, brings with it. On the other hand, despite the increase in the coke yield, am Binder coke no change in its physical properties noticeable in practice. This point is in particular for carbon moldings that are to be subjected to a graphitization process of Meaning.

These advantages of the proposed compounds as a restoring means over those previously used are particularly clear from the following examples.

example 1

20 kg of coal tar pitch coke, for all examples of the same grain composition (10 parts by weight 0.75 to 1.2 mm, 40 parts by weight 0.06 to 0.75 mm, 50 parts by weight <0.06 mm), are mixed with 5 to 5.5 kg of hard pitch a (softening point 78 ° C) and the following table to be removed return means (percentages by weight based on the weight of the hard pitch used) at 120 mixed to 160 ⁰ C and a hydraulic extrusion press to give 70-mm-diameter round electrode in the usual Shaped way, fired in a ring furnace at 1000 ° C for 3 weeks and then graphitized in the usual way.

The properties of the graphitized round electrodes obtained are summarized in Table 4 below.

For comparison, 70 mm diameter round electrodes are made in the same way from a soft pitch of the same provenance (softening point 57 ° C) without one Addition of restoring agents made. The softening points given in Table 4 of the used, The pitches that have been set aside are determined by special stirring-in tests.

TabeUe

Softening point

Coke yield *) density

Pore volume

Flexural strength

kg / cm =

Compressive strength

kg / cm ²

Hard pitch A

Hard pitch A + 15% tar

Hard pitch A + 20% heavy tar oil ...

Hard pitch A + 10% vinyl acetate

Hard pitch A + 5% styrene

Hard pitch A + 10% phthalonitrile

Hard pitch A + 10% acrylonitrile

Soft pitch (without the addition of a restoring agent).
*) Based on pitch and restoring agents.

78

61.5
56

50
57
59.5
54

57

61.1

58.5 53.0

64.2 59.9 73.0 66.4

54.8 1,592

1.578
1.626

1.678
1.634
1.704
1.680

1,589

22.8

23.1
22.5

19.6
20.9
17.5
19.4

23.0

102

95
100

114
120
119
110

97

238

246
246

308
265
347
314

205

1 102 03Ö

ίο

Example 2

Petroleum coke 20 kg of the same particle composition as in Example 1 are mixed with 5 to 5.5 kg of hard pitches (softening points 79, 75, 71,5 ⁰ C) and from the

Restoring agents shown in Tables 5 to 7 below are mixed at 120 to 160 ° C and, as in Example 1 described, processed on 70 mm diameter round electrodes.

Table 5

Softening
Point
° C coke
yield
■ ° / o space
weight
fcg / i Pores
volume
% Bend
strength
kg / cm ² pressure
strength
kg / cm ² Hartoech A. 79
60
60
61
58
55
63.5 59.1
54.2
50.1
54.0
70.3
62.3
51.6 1,548
1.533
1.507
1,542
1.643
1.575
1.517 25.8
25.8
27.1
25.1
21.2
23.3
26.0 79
70
58
70
92
81
70 196
184
162
192
256
204
169 Hard pitch A + 10% light tar oil
Hard pitch A + 15 ° / ₀ heavy tar oil ...
Hard pitch A + 15% tar
Hard pitch A + 10% phthalonitrile
Hard pitch A + 10% azobenzene
Soft pitch (without the addition of a restoring agent) ..

Table 6

Softening
Point
⁰ C coke
yield
7o space
weight
kg / 1 Pores
volume
° / o Bend
strength
kg / cm ² pressure
strength
kg / cm ² Hartoech B. 75
57
58
47.5
49
60.5 55.5
54.3
56.1
71.6
62.0
53.5 1.565
1.544
1.559
1.634
1.617
1.562 25.9
26.7
26.2
22.4
23.3
26.0 90
68
69
104
98
79 205
173
178
254
223
186 Hard pitch B + 10% light tar oil
Hard pitch B + 15% tar
Hard pitch B + 10% phthalonitrile
Hard pitch B + 10% azobenzene
Soft pitch (without the addition of a restoring agent) ..

Table 7

Softening
Point
° C coke
yield
° / o space
weight
kg / 1 Pores
volume
% Bend
strength
kg / cm ² pressure
strength
kg / cm ² Hard pitch C 71.5
54.5
53
54
47.5
48
60.5 57.4
56.0
55.9
57.1
60.7
68.2
56.4 1,572
1,550
1.545
1.574
1,582
1.611
1.565 24.4
25.0
25.8
25.2
24.1
24.1
25.6 85
77
69
87
95
114
89 213
204
210
230
240
269
223 Hard pitch C + 10% light tar oil
Hard pitch C + 15% heavy tar oil
Hard pitch C + 15% tar
Hard pitch C + 10% azobenzene
Hard pitch C + 10% phthalonitrile
Soft pitch (without the addition of a restoring agent) ..

. . hard pitch (softening point 160 ° C) and from the

Example ό Table 8 return means to be taken or

20 kg of petroleum coke of the same grain composition as mixtures according to Example 1 on a 70 mm diameter

in example 1 and 2, about 5 to 5.5 kg of ultra-55 knife round electrodes are processed.

Table 8

Softening
Point
⁰ C coke
yield
° / o space
weight
kg / 1 Pores
volume
° / o Bend
strength
kg / cm ² pressure
strength
kg / cm ² Ultra hard pitch + 20% light tar oil ... 71 67.6 1,590 23.7 106 238 Ultra hard pitch 1
+ 10 o / _o styrene \
+ 10% phthalonitrile J. 55 80.5 1.645 20.4 115 306 Ultra hard pitch 1
+ 5% styrene
+ 15% phthalonitrile J. 77 85.2 1,650 17.9 136 354

-: i.i vhtii'i ·! φ

109 529/619

The superiority of the restoring agents according to the invention over the used so far. With the same additional amount, there is not only a greater reduction in the Processing temperature reached, but also the coke yield increased considerably. In addition, will the quality of the shaped carbon bodies as a result of the increase in density and strengths as well as a decrease in them the pore volume is significantly improved. In all cases, the values are even significantly higher than those of the comparison samples using the original hard pitch, although the softening point has been lowered considerably.

Pitch with a very high softening point can be processed by using mixtures

the proposed return means are achieved, whereby here too-again the superiority of this Substances compared to the restoring agents previously used shows,

Claims (1)

Claim: Use of organic, soluble in the binding pitch Compounds containing one or more active double or triple bonds, individually or in a mixture as a restoring agent (diluent) of the binding pitch for the production of Carbon moldings. 1 sheet of drawings © 109 529/61 »2.61-