EP0174035B1 - Process for preparing needle coke with little irreversible volume expansion from coaltar pitch - Google Patents
Process for preparing needle coke with little irreversible volume expansion from coaltar pitch Download PDFInfo
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- EP0174035B1 EP0174035B1 EP85200849A EP85200849A EP0174035B1 EP 0174035 B1 EP0174035 B1 EP 0174035B1 EP 85200849 A EP85200849 A EP 85200849A EP 85200849 A EP85200849 A EP 85200849A EP 0174035 B1 EP0174035 B1 EP 0174035B1
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- coke
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
- C10B55/00—Coking mineral oils, bitumen, tar, and the like or mixtures thereof with solid carbonaceous material
Definitions
- the invention relates to a process for the production of needle coke from coal tar pitch with small irreversible volume increases during the graphitization of needle coke moldings, e.g. Graphite electrodes for electrical steel production by smoldering coke from Pechen with a quinoline insoluble content of maximum 1.0% by weight.
- the quality of electrographite moldings is determined by several physical properties such as Thermal expansion coefficients, specific electrical and thermal conductivity, ash value, trace elements and density are characterized.
- shaped carbon bodies which are made from petroleum coke or coal tar pitch coke with a binder also show an irreversible increase in volume, the so-called puffing, during the graphitization process in addition to the reversible thermal expansion. Puffing deteriorates the physical properties of the molded body, such as its strength and electrical conductivity.
- High-quality electrographites are made from so-called needle cokes with a linear coefficient of thermal expansion of less than 0.7 10-6 K- 1 (measured in the range 20-200 ° C).
- electrographites of electrodes made from petrostatic needle coke it has been found that the irreversible increase in volume can be correlated with the sulfur content in the calcined coke and can be reduced by adding, for example, iron oxide to the molding paste.
- Patents EP 0087489 B1 and EP 0085121 B1 describe the targeted introduction of intercalation compounds into the graphite and subsequent heating to higher temperatures at which the intercalation compounds spontaneously decompose into gaseous phases in the production of expanded graphite from petroleum coke. This creates an internal overpressure in the graphite. In order to break it down, the gas must diffuse through the crystal layers of the carbon, the crystal layers being expanded irreversibly. At extreme diffusion current densities, expansion factors of 200: 1 to 400: 1 occur.
- Electrographite from high-quality coal tar pitch coke may be puffed using an analogous mechanism and is normally up to 0.9% relative change in length.
- Only macroscopically isotropic cokes can be produced from coal tar pitch with a high content of quinoline-insoluble substances (Q1), from which graphite bodies can be produced without irreversible linear expansion.
- Q1 quinoline-insoluble substances
- JP 5898,385 claims the production of a low-puffing needle coke from coal tar pitch, the content of which is 0.03% in quinoline-insoluble constituents.
- a Fe 2 0 3 content of 0.5% an electrographite is obtained after heat treatment up to 2800 ° C, which only shows an irreversible change in length of 0.5% in the axial direction of the electrode.
- An electrographite made from a coal tar pitch that contains no insoluble components has a change in length of 2.1%.
- the addition of Fe 2 0 3 as an inhibitor cannot be dispensed with.
- the addition of Fe 2 0 3 increases the ash value of the electrographite to an undesirable extent.
- the object of the invention is therefore to develop a method for producing such needle coke from coal tar pitch, which can be processed into low-puffing electrographite without additional inhibiting agents.
- the object is achieved according to the invention in that the ash-forming constituents are removed from the coal tar pitch down to at least 0.01% by weight and the crystalline order of the coke is disturbed by suitable raw material selection and / or by the coking parameters so that the true density of the at 1,300 ° C calcined coke is reduced to an amount of 2.08 to 2.14 g / cm 3 .
- the ash-forming constituents in the feed product can be reduced by known mechanical or thermal processes, as are customary for the separation of solid particles. These processes include, for example, centrifuging and separating, filtering, extracting and promoter-accelerated settling. With this ash removal, however, the puffing can only Ash removal, however, can only partially reduce puffing.
- the crystal structure of coke can be influenced by changing the coking tendency of the feed, e.g. by using selected hard coal tars and pitches, or also by adding up to 50% by weight, based on the pitch, of a high-boiling carbo- and petro-derived hydrocarbon fraction.
- Another option is to vary the coking conditions such as pressure, heating rate, coking time and coking temperature. A combination of both measures is possible, but not necessary in every case.
- feedstocks are pretreated according to the specified procedures in order to ash the pitches.
- the separation takes place in a plate separator at 200 ° C, without the addition of solvents.
- the feed products are filtered through a gap filter with a gap width of 100 to 200 ⁇ m at 240 to 280 ° C and a maximum pressure of 8 - 10 5 Pa is.
- This method is particularly suitable for ash removal from pitches. Ashing by promoter-accelerated settling is also possible, as comparative example 1 shows, and equivalent to separation.
- the feed is mixed homogeneously with 50% by weight of methylnaphthalene and 50% by weight of kerosene, based on the feed, at 175 ° C. and left at 170 ° C. A heavy phase settles on the bottom of the container.
- Coking of the precursor obtained in this way takes place either according to the delayed-coking process under 5 bar at a tube furnace outlet temperature of 480 ° C or in pressure-resistant retorts under a pressure of 1-5 bar and a heating rate of 5 or 10 K / h to 500 ° C instead.
- the coke is crushed, ground and sieved so that there is a uniform granulometry of 100% ⁇ 1 mm 0, 75% ⁇ 0.5 mm 0 and 15% dust ( ⁇ 63 ⁇ m 0).
- the ground coke is made using a commercially available electrode binder that meets the specifications
- the pastes are then extruded into shaped bodies in a suitable device and fired to solid carbon bodies in a conventional manner.
- the burned carbon bodies are graphitized under identical conditions and the irreversible change in shape that occurs is measured.
- puffing is influenced not only by ash removal, but to a considerable extent by the choice of coking conditions.
- the coking process most regarded as the most suitable for coking in retorts with slow heating (5 K / h) and low shear forces results in a coke with relatively high irreversible linear expansion.
- the linear expansion coefficient increases as a result of this procedure, it is still within the range favorable for needle coke.
- the electrical conductivity of the graphitized moldings also increases, which is a further positive feature of the method according to the invention.
Description
Die Erfindung bezieht sich auf ein Verfahren zur Herstellung von Nadelkoks aus Steinkohlenteerpech mit geringen irreversiblen Volumenvergrösserungen während der Graphitierung von Nadelkoks-Formkörpern, z.B. Graphit-Elektroden für die Elektrostahlgewinnung durch Schwelverkoken von Pechen mit einem Chinolinunlöslichengehalt von maximal 1,0 Gew.-%.The invention relates to a process for the production of needle coke from coal tar pitch with small irreversible volume increases during the graphitization of needle coke moldings, e.g. Graphite electrodes for electrical steel production by smoldering coke from Pechen with a quinoline insoluble content of maximum 1.0% by weight.
Die Qualität von Elektrographit-Formkörpern wird durch mehrere physikalische Eigenschaften wie z.B. Wärmeausdehnungskoeffizienten, spezifische elektrische und Wärmeleitfähigkeit, Aschewert, Spurenelemente und Dichte charakterisiert.The quality of electrographite moldings is determined by several physical properties such as Thermal expansion coefficients, specific electrical and thermal conductivity, ash value, trace elements and density are characterized.
Es ist bekannt, dass Kohlenstoff-Formkörper, die aus Petrolkoks oder Steinkohlenteerpechkoks mit einem Bindemittel hergestellt sind, während des Graphitierungsprozesses zusätzlich zur reversiblen Wärmeausdehnung auch eine irreversible Volumenvergrösserung, das sogenannte Puffing zeigen. Durch das Puffing verschlechtern sich die physikalischen Formkörpereigenschaften wie die Festigkeit und die elektrische Leitfähigkeit.It is known that shaped carbon bodies which are made from petroleum coke or coal tar pitch coke with a binder also show an irreversible increase in volume, the so-called puffing, during the graphitization process in addition to the reversible thermal expansion. Puffing deteriorates the physical properties of the molded body, such as its strength and electrical conductivity.
Hochwertige Elektrographite werden aus sogenannten Nadelkoksen mit einem linearen Wärmeausdehnungskoeffizienten von weniger als 0,7 10-6 K-1 (im Bereich 20-200°C gemessen) hergestellt. Bei Elektrographiten von Elektroden aus petrostämmigen Nadelkoksen hat man gefunden, dass die irreversible Volumenvergrösserung mit dem Schwefelgehalt im kalzinierten Koks korrelierbar ist und durch die Zugabe von z.B. Eisenoxid zur Formkörperpaste verringert werden kann.High-quality electrographites are made from so-called needle cokes with a linear coefficient of thermal expansion of less than 0.7 10-6 K- 1 (measured in the range 20-200 ° C). In the case of electrographites of electrodes made from petrostatic needle coke, it has been found that the irreversible increase in volume can be correlated with the sulfur content in the calcined coke and can be reduced by adding, for example, iron oxide to the molding paste.
Dieser Zusammenhang gilt jedoch nicht für Steinkohlenteerpech-Nadelkokse. Bei gleichem Schwefelgehalt zeigen Formkörper aus Steinkohlenteerpech-Nadelkoks ein stärkeres Puffing, das sich durch Zugabe von Fe203 als allgemein gebräuchliches Inhibierungsmittel nur wenig beeinflussen lässt.However, this connection does not apply to coal tar pitch needle coke. With the same sulfur content, moldings made from coal tar pitch coke show a stronger puffing, which can be influenced only little by adding Fe 2 0 3 as a commonly used inhibitor.
In den Preprints der «16th Biennial Conference on Carbon (18./22.07.1983, San Diego, USA; S. 595-596) wird beschrieben, dass das irreversible Puffing von Formkörpern aus Steinkohlenteerpech-Nadelkoks durch Zugabe von 1-2% Cr203 verringert werden kann. Dieses Verfahren ist jedoch grosstechnisch kaum wirtschaftlich realisierbar.In the preprints of the "16th Biennial Conference on Carbon (July 18/22, 1983, San Diego, USA; pp. 595-596) it is described that the irreversible puffing of moldings made from coal tar pitch coke by adding 1-2% Cr 2 0 3 can be reduced. However, this process is hardly economically feasible on an industrial scale.
In den Patenten EP 0087489 B1 und EP 0085121 B1 wird bei der Herstellung von geblähtem Graphit aus Petrolkoksen das gezielte Einbringen von Intercalationsverbindungen in den Graphit sowie ein nachgeschaltetes Erwärmen auf höhere Temperaturen, unter denen sich die Einlagerungsverbindungen spontan in gasförmige Phasen zersetzen, beschrieben. Dabei entsteht ein innerer Überdruck im Graphit. Um diesen abzubauen, muss das Gas durch die Kristallschichten des Kohlenstoffs hindurch diffundieren, wobei die Kristallschichten irreversibel erweitert werden. Bei extremen Diffusionsstromdichten treten Expansionsfaktoren von 200:1 bis 400:1 auf.Patents EP 0087489 B1 and EP 0085121 B1 describe the targeted introduction of intercalation compounds into the graphite and subsequent heating to higher temperatures at which the intercalation compounds spontaneously decompose into gaseous phases in the production of expanded graphite from petroleum coke. This creates an internal overpressure in the graphite. In order to break it down, the gas must diffuse through the crystal layers of the carbon, the crystal layers being expanded irreversibly. At extreme diffusion current densities, expansion factors of 200: 1 to 400: 1 occur.
Das Puffing von Elektrographit aus hochwertigem Steinkohlenteerpech-Nadelkoks erfolgt möglicherweise nach einem analogen Mechanismus und beträgt normalerweise bis 0,9% relative Längenänderung. Aus Steinkohlenteerpechen mit hohem Gehalt an in Chinolin unlöslichen Stoffen (Q1) können nur makroskopisch isotrope Kokse hergestellt werden, aus denen sich Graphitkörper ohne irreversible Längenausdehnung herstellen lassen. Diese haben jedoch eine geringe Leitfähigkeit und einen hohen Wärmeausdehnungskoeffizienten.Electrographite from high-quality coal tar pitch coke may be puffed using an analogous mechanism and is normally up to 0.9% relative change in length. Only macroscopically isotropic cokes can be produced from coal tar pitch with a high content of quinoline-insoluble substances (Q1), from which graphite bodies can be produced without irreversible linear expansion. However, these have a low conductivity and a high coefficient of thermal expansion.
Daraus ergibt sich die Notwendigkeit, das Steinkohlenteerpech als Precursorfür den Steinkohlenteerpech-Nadelkoks von in Chinolin unlöslichen Bestandteilen zu befreien. Hierdurch wird auch die Konzentration schädlicher Einlagerungsverbindungen im Kohlenstoffkörper und damit die zu erwartende Diffusionsstromdichte verringert, wobei jedoch geringe Mengen an schädlichen Verbindungen im Precursor verbleiben. Eine gezielte Schwefel- und Stickstoffverminderung im Rohstoff hingegen ist schwierig.This results in the need to free the coal tar pitch as a precursor for the coal tar pitch needle coke from quinoline-insoluble constituents. This also reduces the concentration of harmful intercalation compounds in the carbon body and thus the expected diffusion current density, but small amounts of harmful compounds remain in the precursor. A targeted reduction in sulfur and nitrogen in the raw material, however, is difficult.
Im JP 5898,385 wird die Herstellung eines puffingarmen Nadelkokses aus Steinkohlenteerpech beansprucht, dessen Gehalt an in Chinolin unlöslichen Bestandteilen 0,03% beträgt. Mit einem Fe203-Anteil von 0,5% wird nach einer Wärmebehandlung bis 2800°C ein Elektrographit erhalten, der in Achsrichtung der Elektrode nur noch eine irreversible Längenänderung von 0,5% aufweist. Ein Elektrographit aus einem Steinkohlenteerpech, das keine unlöslichen Bestandteile enthält, hat eine Längenänderung von 2,1%. Auch auf der Basis von aschearmem Steinkohlenteerpech als Rohstoff für den Nadelkoks und damit für den Elektrographit kann daher nicht auf den Zusatz von Fe203 als Inhibitor verzichtet werden. Der Zusatz von Fe203 erhöht jedoch im unerwünschten Masse den Aschewert des Elektrographits.JP 5898,385 claims the production of a low-puffing needle coke from coal tar pitch, the content of which is 0.03% in quinoline-insoluble constituents. With a Fe 2 0 3 content of 0.5%, an electrographite is obtained after heat treatment up to 2800 ° C, which only shows an irreversible change in length of 0.5% in the axial direction of the electrode. An electrographite made from a coal tar pitch that contains no insoluble components has a change in length of 2.1%. Even on the basis of low-ash coal tar pitch as a raw material for needle coke and thus for electrographite, the addition of Fe 2 0 3 as an inhibitor cannot be dispensed with. However, the addition of Fe 2 0 3 increases the ash value of the electrographite to an undesirable extent.
Aufgabe der Erfindung ist es deshalb, ein Verfahren zur Herstellung eines solchen Nadelkokses aus Steinkohlenteerpech zu entwickeln, der ohne zusätzliche Inhibierungsmittel zu puffingarmem Elektrographit verarbeitet werden kann.The object of the invention is therefore to develop a method for producing such needle coke from coal tar pitch, which can be processed into low-puffing electrographite without additional inhibiting agents.
Die Aufgabe wird erfindungsgemäss dadurch gelöst, dass die aschebildenden Bestandteile aus dem Steinkohlenteerpech bis auf mindestens 0,01 Gew.-% entfernt werden und die kristalline Ordnung des Kokses durch geeignete Rohstoffauswahl und/oder durch die Verkokungsparameter so gestört wird, dass die wahre Dichte des bei 1 300°C kalzinierten Kokses auf einen Betrag von 2,08 bis 2,14 g/cm3 verringert wird.The object is achieved according to the invention in that the ash-forming constituents are removed from the coal tar pitch down to at least 0.01% by weight and the crystalline order of the coke is disturbed by suitable raw material selection and / or by the coking parameters so that the true density of the at 1,300 ° C calcined coke is reduced to an amount of 2.08 to 2.14 g / cm 3 .
Die aschebildenden Bestandteile im Einsatzprodukt lassen sich durch bekannte mechanische oder thermische Verfahren, wie sie zur Abtrennung von Feststoffpartikeln üblich sind, verringern. Zu diesen Verfahren gehören beispielsweise das Zentrifugieren und Separieren, das Filtrieren, das Extrahieren und das promotorbeschleunigte Absitzenlassen (Settlen). Durch diese Ascheentfernung kann das Puffing jedoch nur zu Ascheentfernung kann das Puffing jedoch nur zu einem Teil vermindert werden.The ash-forming constituents in the feed product can be reduced by known mechanical or thermal processes, as are customary for the separation of solid particles. These processes include, for example, centrifuging and separating, filtering, extracting and promoter-accelerated settling. With this ash removal, however, the puffing can only Ash removal, however, can only partially reduce puffing.
Die Kristallstruktur von Koksen lässt sich durch Veränderung der Verkokungsneigung des Einsatzproduktes beeinflussen, z.B. durch Verwendung ausgewählter Steinkohlenteere und Peche, oder aber auch durch Zumischen von bis zu 50 Gew.-%, bezogen auf das Pech, einer hochsiedenden carbo- und petrostämmigen Kohlenwasserstofffraktion. Eine andere Möglichkeit ist die Variation der Verkokungsbedingungen wie Druck, Aufheizgeschwindigkeit, Verkokungszeit und Verkokungstemperatur. Eine Kombination beider Massnahmen ist möglich, aber nicht in jedem Fall erforderlich.The crystal structure of coke can be influenced by changing the coking tendency of the feed, e.g. by using selected hard coal tars and pitches, or also by adding up to 50% by weight, based on the pitch, of a high-boiling carbo- and petro-derived hydrocarbon fraction. Another option is to vary the coking conditions such as pressure, heating rate, coking time and coking temperature. A combination of both measures is possible, but not necessary in every case.
Beim verfahrensgemäss beanspruchten Vorgehen erhält man durch Schwelverkokung und anschliessende Kalzination bis zu 1 300°C, beispielsweise Kokse, die sich durch folgende Daten charakterisieren lassen:
Anhand einiger ausgewählter Versuchsdaten in Tabelle 1 ist zu erkennen, dass durch Variation der Massnahmen (1) und (2) Nadelkokse erhalten werden, die sich durch unterschiedliche Dichten und Aschewerte auszeichnen. Die wahre Dichte ß ist als einfache Messgrösse ein Mass für den kristallinen Orientierungsgrad im Koks.On the basis of some selected test data in Table 1, it can be seen that by varying measures (1) and (2), needle coke is obtained which is characterized by different densities and ash values. As a simple measurement, the true density ß is a measure of the degree of crystalline orientation in the coke.
Werden diese erhaltenen Kokse anschliessend unter bekannten, gleichbleibenden Bedingungen (Journal of Materials Science 18, 1983, Seiten 3161 EZ 176) zu Formkörpern verarbeitet und bis 2500°C graphitiert, findet man unterschiedliche irreversible Längenänderungen.If these cokes obtained are then processed under known, constant conditions (Journal of Materials Science 18, 1983, pages 3161 EZ 176) into shaped bodies and graphitized up to 2500 ° C., different irreversible changes in length are found.
Überrraschend an diesen Untersuchungen ist die Tatsache, dass Kokse mit gleichem Aschewert bei geringerer Dichte, d.h. bei geringerer kristalliner Ordnung ein deutlich verbessertes Puffingverhalten zeigen, ohne dass die Nadelkokseigenschaften in unzulässiger Weise verschlechtert werden. Es muss angenommen werden, dass neben der Verminderung der für das Puffing mitverantwortlichen Aschebestandteile die gestörten Kristallstrukturen des Kokses die Diffusion der durch die verbleibenden Einlagerungsverbindungen beim Graphitieren entstehenden Gase erleichter, so dass ein Aufblähen der Graphitstruktur vermindert wird.What is surprising about these investigations is the fact that cokes with the same ash value at lower density, i.e. show a significantly improved puffing behavior with a lower crystalline order, without the needle coke properties being impaired in an impermissible manner. It must be assumed that in addition to the reduction of the ash components that are responsible for the puffing, the disturbed crystal structures of the coke facilitate the diffusion of the gases produced by the remaining intercalation compounds during the graphitization, so that the graphite structure is expanded.
Mit den beschriebenen Massnahmen - Verringerung der Aschebildner im Pech und Beeinflussung der Kristallinität des Pechkokses - zur Beeinflussung irreversibler Längenausdehnungen bei Pech-Nadelkoksen ist eine Möglichkeit gefunden, das unerwünschte Formkörper-Puffing ohne verunreinigende Zusätze zu minimieren.With the measures described - reducing the ash builders in the pitch and influencing the crystallinity of the pitch coke - for influencing irreversible linear expansion in the case of pitch needle cokes, a way has been found to minimize the undesired molding puffing without contaminating additives.
Die Einzelmassnahmen sind für sich allein wirksam, aber erst in Kombination bewirken sie ein optimales Ergebnis. Die Erfindung wird anhand der nachfolgenden Beispiele näher erläutert, ohne darauf beschränkt zu sein.The individual measures are effective on their own, but only in combination do they achieve an optimal result. The invention is explained in more detail with reference to the following examples, without being restricted thereto.
Es werden 10 Kokse gegenübergestellt, die aus Pechen, teilweise in Mischung mit hocharomatischen Ölen, mit geringem Gehalt an in Chinolin unlöslichen Stoffen (QI) hergestellt werden. Die Einsatzprodukte sind durch folgende Analysendaten gekennzeichnet:
Siedebereich 355 bis 470°C.10 cokes are compared, which are made from pitches, partly in a mixture with highly aromatic oils, with a low content of quinoline-insoluble substances (QI). The input products are characterized by the following analysis data:
Boiling range 355 to 470 ° C.
Diese Einsatzprodukte werden nach den angegebenen Verfahren vorbehandelt, um die Peche zu entaschen. Das Separieren erfolgt in einem Tellerseparator bei 200°C, ohne Zusatz von Lösungsmitteln. Filtriert werden die Einsatzprodukte über ein Spaltfilter mit 100 bis 200 um Spaltweite bei 240 bis 280°C und einem maximalen Druck von 8 - 105 Pa, wobei den Einsatzprodukten eine übliche Filterhilfe zugesetzt wird, deren Anteil bis zum Doppelten der Menge an Chinolinunlöslichem im Einsatzprodukt beträgt. Dieses Verfahren ist zur Entaschung von Pechen besonders geeignet. Eine Entaschung durch promotorbeschleunigtes Absetzenlassen (Settlen) ist ebenfalls möglich, wie das Vergleichsbeispiel 1 zeigt, und dem Separieren gleichwertig. Das Einsatzprodukt wird hierbei mit 50 Gew.-% Methylnaphthalin und 50 Gew.-% Kerosin, bezogen auf das Einsatzprodukt, bei 175°C homogen durchmischt und bei 170°C stehengelassen. Dabei setzt sich eine schwere Phase am Boden des Behälters ab. Die überstehende leichte Phase wird abgenommen und durch Flashdestillation von den leichtsiedenden Lösungsmitteln befreit. Die Verkokung des so gewonnenen Precursors findet entweder nach dem Delayed-Coking-Verfahren unter 5 bar bei einer Röhrenofenaustrittstemperatur von 480°C oder in druckfesten Retorten unter einem Druck von 1-5 bar und einer Aufheizgeschwindigkeit von 5 bzw. 10 K/h bis 500°C statt.These feedstocks are pretreated according to the specified procedures in order to ash the pitches. The separation takes place in a plate separator at 200 ° C, without the addition of solvents. The feed products are filtered through a gap filter with a gap width of 100 to 200 µm at 240 to 280 ° C and a maximum pressure of 8 - 10 5 Pa is. This method is particularly suitable for ash removal from pitches. Ashing by promoter-accelerated settling is also possible, as comparative example 1 shows, and equivalent to separation. The feed is mixed homogeneously with 50% by weight of methylnaphthalene and 50% by weight of kerosene, based on the feed, at 175 ° C. and left at 170 ° C. A heavy phase settles on the bottom of the container. The remaining light phase is removed and the low-boiling solvents are removed by flash distillation. Coking of the precursor obtained in this way takes place either according to the delayed-coking process under 5 bar at a tube furnace outlet temperature of 480 ° C or in pressure-resistant retorts under a pressure of 1-5 bar and a heating rate of 5 or 10 K / h to 500 ° C instead.
Durch unterschiedliche Vorbehandlungen und Verkokungsbedingungen werden Kokse mit verschiedenen Aschegehalten und wahren Dichten, gemessen am bei 1300°C kalzinierten Koks, gewonnen.Different pretreatments and coking conditions produce cokes with different ash contents and true densities, measured on coke calcined at 1300 ° C.
Die Kokse werden so zerkleinert, gemahlen und abgesiebt, dass eine einheitliche Granulometrie von 100% <1 mm 0, 75%<0,5 mm 0 und 15% Staub (<63 µm 0) vorliegt.The coke is crushed, ground and sieved so that there is a uniform granulometry of 100% <1 mm 0, 75% <0.5 mm 0 and 15% dust (<63 µm 0).
Die gemahlenen Kokse werden mit einem handelsüblichen Elektrodenbinder, der die SpezifikationenThe ground coke is made using a commercially available electrode binder that meets the specifications
Anschliessend werden die Pasten in einer geeigneten Vorrichtung zu Formkörpern extrudiert und in herkömmlicher Weise zu festen Kohlenstoffkörpern gebrannt.The pastes are then extruded into shaped bodies in a suitable device and fired to solid carbon bodies in a conventional manner.
Die gebrannten Kohlenstoffkörper werden unter identischen Bedingungen graphitiert und die dabei auftretende irreversible Formänderung vermessen.The burned carbon bodies are graphitized under identical conditions and the irreversible change in shape that occurs is measured.
Die Ergebnisse sind in der Tabelle 2 wiedergegeben.
Wie ein Vergleich der Beispiele 1 und 2 mit den entsprechenden Vergleichsbeispielen zeigt, wird das Puffing nicht allein durch das Entaschen, sondern in erheblichem Masse durch die Wahl der Verkokungsbedingungen beeinflusst. So ergibt das für die Verkokung am günstigsten angesehene Verkokungsverfahren in Retorten bei langsamer Aufheizung (5 K/h) und geringen Scherkräften einen Koks mit noch relativ hohen irreversiblen Längenausdehnungen. Das Delayed-Coking-Verfahren mit schneller Aufheizung und danach nahezu konstant gehaltener Temperatur bei grossen Scherkräften, wodurch das Wachstum grosser Kristallite verhindert wird, führt hingegen zu einem Koks mit geringerem Puffing. Der lineare Ausdehnungskoeffizient steigt durch diese Verfahrensweise zwar an, liegt aber noch innerhalb des für Nadelkokse günstigen Bereichs. Zusätzlich erhöht sich ausserdem die elektrische Leitfähigkeit der graphitierten Formkörper, was ein weiteres positives Merkmal des erfindungsgemässen Verfahrens ist.As a comparison of Examples 1 and 2 with the corresponding comparative examples shows, puffing is influenced not only by ash removal, but to a considerable extent by the choice of coking conditions. For example, the coking process most regarded as the most suitable for coking in retorts with slow heating (5 K / h) and low shear forces results in a coke with relatively high irreversible linear expansion. The delayed coking process with rapid heating and then almost constant temperature at high shear forces, which prevents the growth of large crystallites, leads to a coke with less puffing. Although the linear expansion coefficient increases as a result of this procedure, it is still within the range favorable for needle coke. In addition, the electrical conductivity of the graphitized moldings also increases, which is a further positive feature of the method according to the invention.
Claims (7)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3432886 | 1984-09-07 | ||
| DE19843432886 DE3432886A1 (en) | 1984-09-07 | 1984-09-07 | METHOD FOR PRODUCING NEEDLE COOKS WITH LOW IRREVERSIBLE VOLUME EXPANSIONS FROM CHARCOAL TEE |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0174035A2 EP0174035A2 (en) | 1986-03-12 |
| EP0174035A3 EP0174035A3 (en) | 1987-05-20 |
| EP0174035B1 true EP0174035B1 (en) | 1988-10-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP85200849A Expired EP0174035B1 (en) | 1984-09-07 | 1985-05-28 | Process for preparing needle coke with little irreversible volume expansion from coaltar pitch |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0174035B1 (en) |
| DE (2) | DE3432886A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4933976A (en) * | 1988-01-25 | 1990-06-12 | C.F.A. Technologies, Inc. | System for generating rolled fingerprint images |
| CN114364769A (en) * | 2019-09-17 | 2022-04-15 | 日铁化学材料株式会社 | Low CTE, low puffing needle coke |
| CN115404090B (en) * | 2022-09-22 | 2023-08-08 | 西北大学 | Method for preparing needle coke by compounding coal-based and petroleum-based components |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3799865A (en) * | 1971-11-30 | 1974-03-26 | Nittetsu Chem Ind Co | Process for producing needle-shaped coal pitch coke |
| JPS6041111B2 (en) * | 1976-11-26 | 1985-09-13 | 新日鐵化学株式会社 | Method for preparing raw materials for coke production |
| JPS5641817A (en) * | 1979-09-06 | 1981-04-18 | Mitsubishi Chem Ind Ltd | Manufacture of molded carbon material |
| DE3142826A1 (en) * | 1981-10-29 | 1983-05-11 | Rütgerswerke AG, 6000 Frankfurt | METHOD FOR PRODUCING A HIGHLY REACTIVE PECH FRACTION AND THE USE THEREOF |
-
1984
- 1984-09-07 DE DE19843432886 patent/DE3432886A1/en not_active Withdrawn
-
1985
- 1985-05-28 DE DE8585200849T patent/DE3565854D1/en not_active Expired
- 1985-05-28 EP EP85200849A patent/EP0174035B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| EP0174035A2 (en) | 1986-03-12 |
| DE3432886A1 (en) | 1986-03-20 |
| DE3565854D1 (en) | 1988-12-01 |
| EP0174035A3 (en) | 1987-05-20 |
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