EP0718415B1 - Anti-coking steels - Google Patents

Anti-coking steels Download PDF

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Publication number
EP0718415B1
EP0718415B1 EP95402864A EP95402864A EP0718415B1 EP 0718415 B1 EP0718415 B1 EP 0718415B1 EP 95402864 A EP95402864 A EP 95402864A EP 95402864 A EP95402864 A EP 95402864A EP 0718415 B1 EP0718415 B1 EP 0718415B1
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EP
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Prior art keywords
steel
coking
steels
nickel
process according
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EP95402864A
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German (de)
French (fr)
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EP0718415A1 (en
Inventor
Valérie Mousseaux
François Ropital
André Le Lido Casanova A2 Sugier
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IFP Energies Nouvelles IFPEN
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IFP Energies Nouvelles IFPEN
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G9/00—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
    • C10G9/14—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils in pipes or coils with or without auxiliary means, e.g. digesters, soaking drums, expansion means
    • C10G9/16—Preventing or removing incrustation
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G9/00—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
    • C10G9/14—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils in pipes or coils with or without auxiliary means, e.g. digesters, soaking drums, expansion means
    • C10G9/18—Apparatus
    • C10G9/20—Tube furnaces
    • C10G9/203—Tube furnaces chemical composition of the tubes
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium

Definitions

  • the present invention relates to steels intended to manufacture reactors, furnaces, pipes or certain of their elements used in particular in petrochemical processes, these steels having an improved resistance to coking.
  • the invention also relates to the manufacture of reactors, furnaces, pipes or some of their elements, using these steels.
  • coke The carbonaceous deposit that develops in furnaces during the conversion of hydrocarbons.
  • This deposit of coke is harmful in industrial units. Indeed, the formation of coke on the walls of the tubes and reactors leads in particular to a reduction in heat exchanges, significant blockages and therefore increases in pressure drops. To keep a constant reaction temperature, it may be necessary to increase the temperature of the walls, which risks causing damage to the alloy constituting these walls. There is also a decrease in the selectivity of the installations and therefore in the yield.
  • EP-A-0 190 408 describes an austenitic steel for coal gasification devices.
  • Application JP 03-104843 is known, which describes an anti-coking refractory steel for an ethylene steam cracking furnace tube. But this steel contains more than 15% chromium and nickel, and less than 0.4% manganese. This steel is developed to limit the formation of coke between 750 ° C and 900 ° C for the steam cracking of naphtha, ethane or diesel.
  • the steels of the invention may also contain from 0.25 to about 0.5% by weight of titanium.
  • the invention also relates to a method for manufacturing plant elements intended for petrochemical processes taking place at temperatures between 350 and 1100 ° C., in which, to improve the resistance to coking of said elements, they are manufactured in all or part of it, using steel as defined above.
  • These steels can be used to manufacture installations using petrochemical processes, for example, catalytic or thermal cracking and dehydrogenation.
  • Another application may relate to a process of steam cracking of products such as naphtha, ethane or a gas oil, which leads to the formation of light unsaturated hydrocarbons, in particular ethylene, etc. at temperatures from 750 ° C. to 1100 ° C.
  • the steels according to the invention can be used to manufacture whole tubes or plates intended for the manufacture of furnaces or reactors.
  • the steels according to the present invention can be produced by the conventional foundry and molding methods, then shaped by the usual techniques to manufacture sheets, grids, tubes, profiles, etc. semi-finished products can be used to build the main parts of reactors or only accessory or auxiliary parts.
  • the steels according to the invention can also be used for covering the internal walls of furnaces, reactors or pipes, by at least one of the following techniques: co-centrifugation, plasma, electrolytic, "overlay”. These steels can then be used in powder form to coat the internal walls of the reactors, grids or tubes, in particular after installation of the installations.
  • the steels used in the examples have the compositions indicated below (% by weight): STEELS VS Yes Mn Or Cr S P Al Ti AS 0.06 0.5 1.1 10 17.5 0.015 ⁇ 0.04 0.07 0.5 F1 0.37 2.31 10.25 D1 0.04 1.9 1.8 12.5 19.3 0.001 0.02 0.06 0.005 D2 0.2 3.6 0.8 14.5 18.5 0.015 ⁇ 0.04 1.0 ⁇ 0.01 C1 0.06 5 1.2 10 17.5 0.015 ⁇ 0.04 0.07 0.5 C2 0.06 3.5 1.2 10 17.5 0.015 ⁇ 0.04 0.07 0.5 C3 0.05 3 1.2 12 17.5 0.015 ⁇ 0.04 0.06 0.35 C4 0.05 2.5 1.2 12 17.0 0.05 ⁇ 0.04 0.06 0.35
  • AS is a standard steel commonly used for the manufacture of reactors or reactor components. Steels F1, D1 and D2 are also presented for comparison.
  • the isobutane dehydrogenation reaction makes it possible to obtain isobutene.
  • a side reaction is the formation of coke.
  • the coke deposit consists mainly of coke of catalytic origin.
  • the steel F1 has a ferritic structure, the steels C1 and C2 an austeno-ferritic structure and the steels C3 and C4 an austenitic structure.
  • the chromium and nickel contents of steels C3 and C4 were adjusted using the equivalence coefficients of Guiraldenq and Pryce, in order to locate these steels in the austenitic single-phase domain of the Schaeffer diagram.
  • Alloys C1, C2, C3 and C4 have the ability to develop a stable and inert oxide layer vis-à-vis catalytic coking phenomena.
  • the presence of silicon in these alloys promotes the formation of an outer and substantially continuous layer practically consisting solely of chromium oxide without Cr_Ni_Fe spinel oxides.
  • This chromium oxide layer is separated from the metal substrate by an oxide zone rich in silicon.
  • the atmosphere of the chemical reaction, for example of dehydrogenation of isobutane is then practically only in contact with a chromium oxide layer catalytically inert vis-à-vis the coking phenomenon.
  • the microbalance makes it possible to continuously measure the gain in mass on the sample.
  • FIG. 1 shows a graph having the time in hours on the abscissa and the ordinate the mass of coke which forms on the sample during the reaction, mass given in grams per square meter (g / m 2 ).
  • Curve 1 relates to AS steel, curve 2 to F1 steel, curves 3 and 3b respectively to steels D1 and D2, all 4 curves to steels C1, C2, C3 and C4.
  • Figure 2 shows the coking curves during several successive coking / decoking cycles.
  • the decoking was carried out in air at 600 ° C, for the time necessary to burn the deposited coke (5 to 10 minutes).
  • Curve 6 represents coking for AS steel in the first cycle
  • curve 5 represents coking for AS steel sample after 20 coking / decoking cycles.
  • Curves 7 represent the coking / decoking curves after 20 cycles for steels C3 and C4.
  • steels C3 and C4 After 20 coking / decoking cycles, steels C3 and C4 have the same resistance to coking. Their surface chromium oxide layer has not evolved and it has retained its very low original catalytic activity with regard to coking. On the other hand, for standard steel which contains practically no silicon, after 20 coking / decoking cycles, the carbon deposition rate after 6 hours of testing has been multiplied by four.
  • the protective layer of standard steel is not stable: during successive decoking, there is an enrichment of this layer with catalytic metallic element such as iron or nickel.
  • a second test was carried out with a steam cracking reaction of hexane at a temperature of about 850 ° C.
  • the protocol for preparing the steel samples and for testing is the same as for Example 1.
  • FIG. 3 shows the coking of a steel sample AS, represented by curve 8, clearly superior to curves 9 and 10 representing respectively the coking of samples of steels C4 and C3.
  • the C3 and C4 alloys which contain in particular silicon have a lower coking rate than that of standard steels.
  • Column 1 corresponds to the temperature of the sample, column 2 to the stress at the elastic limit, column 3 to the stress at break, column 4 to the elongation at break.
  • Column 5 corresponds to the breaking stress in the creep test after 10,000 hours, column 6 after the 100,000 hours, and column 7 to the stress for an elongation of 1% in the creep test after 10,000 hours.

Abstract

Steel consists of in wt%: approx 0.05 C; 2.5-5 Si; 10-20Cr; 10-15 Ni; 0.5-1.5 Mn; max 0.8 Al; balance Fe. The steel may also contain 0.25-0.5 Ti.

Description

La présente invention concerne des aciers destinés à fabriquer des réacteurs, des fours, des conduites ou certains de leurs éléments utilisés notamment dans des procédés pétrochimiques, ces aciers ayant une résistance au cokage améliorée.The present invention relates to steels intended to manufacture reactors, furnaces, pipes or certain of their elements used in particular in petrochemical processes, these steels having an improved resistance to coking.

L'invention concerne également la fabrication de réacteurs, de fours, de conduites ou de certains de leurs éléments, au moyen de ces aciers.The invention also relates to the manufacture of reactors, furnaces, pipes or some of their elements, using these steels.

Le dépôt carboné qui se développe dans les fours lors de la conversion des hydrocarbures est généralement appelé coke. Ce dépôt de coke est néfaste dans les unités industrielles. En effet, la formation du coke sur les parois des tubes et des réacteurs entraîne notamment une diminution des échanges thermiques, des bouchages importants et donc des augmentations de pertes de charge. Pour conserver une température de réaction constante, il peut être nécessaire d'augmenter la température des parois, ce qui risque d'entraîner un endommagement de l'alliage constitutif de ces parois. On observe aussi une diminution de la sélectivité des installations et par conséquent du rendement.The carbonaceous deposit that develops in furnaces during the conversion of hydrocarbons is generally called coke. This deposit of coke is harmful in industrial units. Indeed, the formation of coke on the walls of the tubes and reactors leads in particular to a reduction in heat exchanges, significant blockages and therefore increases in pressure drops. To keep a constant reaction temperature, it may be necessary to increase the temperature of the walls, which risks causing damage to the alloy constituting these walls. There is also a decrease in the selectivity of the installations and therefore in the yield.

Il s'avère donc nécessaire d'arrêter périodiquement les installations afin de procéder à un décokage. Il est donc intéressant économiquement de développer des matériaux ou des revêtements susceptibles de diminuer la formation du coke.It is therefore necessary to periodically stop the installations in order to carry out decoking. It is therefore economically advantageous to develop materials or coatings capable of reducing the formation of coke.

Le document EP-A-0 190 408 décrit un acier austenitique pour des dispositifs de gazéification du charbon.EP-A-0 190 408 describes an austenitic steel for coal gasification devices.

On connaît la demande JP 03-104843 qui décrit un acier réfractaire anti-cokage pour tube de four de vapocraquage à l'éthylène. Mais cet acier comporte plus de 15 % de chrome et de nickel, et moins de 0,4 % de manganèse. Cet acier est développé pour limiter la formation du coke entre 750°C et 900°C pour le vapocraquage d'un naphta, d'éthane ou d'un gasoil.Application JP 03-104843 is known, which describes an anti-coking refractory steel for an ethylene steam cracking furnace tube. But this steel contains more than 15% chromium and nickel, and less than 0.4% manganese. This steel is developed to limit the formation of coke between 750 ° C and 900 ° C for the steam cracking of naphtha, ethane or diesel.

Ainsi, la présente invention concerne des aciers de composition déterminée pour obtenir une bonne résistance au cokage. Ces aciers ont la composition pondérale suivante :

  • environ 0,05 ou environ 0,06 % de carbone,
  • de 2,5 % à 5 % de silicium,
  • de 10 % à 20 % de chrome,
  • de 10 à 15 % de nickel,
  • de 0,5% à 1,5 % de manganèse,
  • au plus 0,8 % d'aluminium,
  • le complément à 100 % étant du fer et des impuretés inévitables.
Thus, the present invention relates to steels of composition determined to obtain good resistance to coking. These steels have the following weight composition:
  • about 0.05 or about 0.06% carbon,
  • from 2.5% to 5% of silicon,
  • from 10% to 20% chromium,
  • from 10 to 15% nickel,
  • from 0.5% to 1.5% manganese,
  • at most 0.8% aluminum,
  • the 100% supplement being iron and unavoidable impurities.

Les aciers de l'invention peuvent contenir en outre de 0,25 à environ 0,5 % en poids de titane.The steels of the invention may also contain from 0.25 to about 0.5% by weight of titanium.

Selon une variante de l'invention, les aciers peuvent avoir la composition pondérale suivante :

  • 0,06 % de carbone,
  • 3,5% à 5 % de silicium,
  • 17,5 % de chrome,
  • 10 % de nickel,
  • 1,2 % de manganèse,
  • 0,5 % de titane,
  • 0,07 % l'aluminium,
  • le complément à 100 % étant du fer et des impuretés inévitables.
According to a variant of the invention, the steels can have the following weight composition:
  • 0.06% carbon,
  • 3.5% to 5% silicon,
  • 17.5% chromium,
  • 10% nickel,
  • 1.2% manganese,
  • 0.5% titanium,
  • 0.07% aluminum,
  • the 100% supplement being iron and unavoidable impurities.

Ils peuvent alors présenter une structure austéno-ferritique.They can then have an austenitic-ferritic structure.

Selon une autre variante de l'invention, les aciers peuvent avoir la composition pondérale suivante :

  • 0,05 % de carbone,
  • 2,5 % à 3 % de silicium,
  • 17 à 17,5 % de chrome,
  • 12 % de nickel,
  • 1,2 % de manganèse,
  • 0,35 % de titane,
  • et 0,06 % d'aluminium,
  • le complément à 100 % étant du fer et des impuretés inévitables.
According to another variant of the invention, the steels can have the following weight composition:
  • 0.05% carbon,
  • 2.5% to 3% silicon,
  • 17 to 17.5% chromium,
  • 12% nickel,
  • 1.2% manganese,
  • 0.35% titanium,
  • and 0.06% aluminum,
  • the 100% supplement being iron and unavoidable impurities.

Ils peuvent alors présenter une structure austénitique.They can then have an austenitic structure.

L'invention concerne également un procédé de fabrication d'éléments d'installations destinées à des procédés pétrochimiques se déroulant à des températures comprises entre 350 et 1100°C, dans lequel, pour améliorer la résistance au cokage desdits éléments, on les fabrique, dans leur totalité ou en partie, en utilisant un acier tel que défini plus haut.The invention also relates to a method for manufacturing plant elements intended for petrochemical processes taking place at temperatures between 350 and 1100 ° C., in which, to improve the resistance to coking of said elements, they are manufactured in all or part of it, using steel as defined above.

Ces aciers peuvent être utilisés pour fabriquer des installations mettant en oeuvre des procédés pétrochimiques, par exemple, le craquage catalytique ou thermique et la déshydrogénation.These steels can be used to manufacture installations using petrochemical processes, for example, catalytic or thermal cracking and dehydrogenation.

Par exemple, pendant la réaction de déshydrogénation de l'isobutane qui permet d'obtenir de l'isobutène entre 550°C et 700°C, une réaction secondaire produit la formation de coke. Cette formation de coke est catalytiquement activée par la présence de nickel, fer et de leurs oxydes.For example, during the dehydrogenation reaction of isobutane which makes it possible to obtain isobutene between 550 ° C. and 700 ° C., a secondary reaction produces the formation of coke. This coke formation is catalytically activated by the presence of nickel, iron and their oxides.

Une autre application peut concerner un procédé de vapocraquage de produits comme un naphta, l'éthane ou un gasoil, qui conduit à la formation d'hydrocarbures insaturés légers, notamment l'éthylène, etc... à des températures de 750°C à 1100°C.Another application may relate to a process of steam cracking of products such as naphtha, ethane or a gas oil, which leads to the formation of light unsaturated hydrocarbons, in particular ethylene, etc. at temperatures from 750 ° C. to 1100 ° C.

Les aciers selon l'invention peuvent être utilisés pour fabriquer en totalité des tubes ou des plaques destinés à la fabrication de fours ou de réacteurs.The steels according to the invention can be used to manufacture whole tubes or plates intended for the manufacture of furnaces or reactors.

Dans ce cas, les aciers selon la présente invention peuvent être élaborés par les méthodes classiques de fonderie et de moulage, puis mis en forme par les techniques usuelles pour fabriquer des tôles, des grilles, des tubes, des profilés, etc...Ces produits semi-finis peuvent être utilisés pour construire les parties principales des réacteurs ou seulement des parties accessoires ou auxiliaires.In this case, the steels according to the present invention can be produced by the conventional foundry and molding methods, then shaped by the usual techniques to manufacture sheets, grids, tubes, profiles, etc. semi-finished products can be used to build the main parts of reactors or only accessory or auxiliary parts.

On peut également utiliser les aciers selon l'invention pour le recouvrement des parois internes de fours, réacteurs, ou conduites, par l'une au moins des techniques suivantes : co-centrifugation, plasma, électrolytique, "overlay". Ces aciers peuvent alors être utilisés sous forme de poudre pour effectuer des revêtements des parois internes des réacteurs, des grilles ou tubes, en particulier après montage des installations.The steels according to the invention can also be used for covering the internal walls of furnaces, reactors or pipes, by at least one of the following techniques: co-centrifugation, plasma, electrolytic, "overlay". These steels can then be used in powder form to coat the internal walls of the reactors, grids or tubes, in particular after installation of the installations.

L'invention sera mieux comprise et ses avantages apparaîtront plus clairement à la lecture des exemples et des essais, nullement limitatifs, qui suivent, illustrés par les figures ci-annexées parmi lesquelles :

  • la figure 1 montre les courbes de cokage de différents aciers au cours d'une réaction de déshydrogénation de l'isobutane,
  • la figure 2 compare l'effet cumulé de cokage puis décokage pour les aciers selon l'invention en comparaison avec un acier standard pour la même réaction,
  • la figure 3 montre des courbes de cokage pour différents aciers pour une :réaction de vapocraquage de l'hexane.
The invention will be better understood and its advantages will appear more clearly on reading the examples and tests, which are in no way limitative, which follow, illustrated by the appended figures among which:
  • FIG. 1 shows the coking curves of various steels during a dehydrogenation reaction of isobutane,
  • FIG. 2 compares the cumulative effect of coking and then decoking for the steels according to the invention in comparison with a standard steel for the same reaction,
  • Figure 3 shows coking curves for different steels for a: steam cracking reaction of hexane.

Les aciers utilisés dans les exemples ont les compositions indiquées ci-après (% poids) : ACIERS C Si Mn Ni Cr S P Al Ti AS 0,06 0,5 1,1 10 17,5 0,015 <0,04 0,07 0,5 F1 0,37 2,31 10,25 D1 0,04 1,9 1,8 12,5 19,3 0,001 0,02 0,06 0,005 D2 0,2 3,6 0,8 14,5 18,5 0,015 <0,04 1,0 <0,01 C1 0,06 5 1,2 10 17,5 0,015 <0,04 0,07 0,5 C2 0,06 3,5 1,2 10 17,5 0,015 <0,04 0,07 0,5 C3 0,05 3 1,2 12 17,5 0,015 <0,04 0,06 0,35 C4 0,05 2,5 1,2 12 17,0 0,05 <0,04 0,06 0,35 The steels used in the examples have the compositions indicated below (% by weight): STEELS VS Yes Mn Or Cr S P Al Ti AS 0.06 0.5 1.1 10 17.5 0.015 <0.04 0.07 0.5 F1 0.37 2.31 10.25 D1 0.04 1.9 1.8 12.5 19.3 0.001 0.02 0.06 0.005 D2 0.2 3.6 0.8 14.5 18.5 0.015 <0.04 1.0 <0.01 C1 0.06 5 1.2 10 17.5 0.015 <0.04 0.07 0.5 C2 0.06 3.5 1.2 10 17.5 0.015 <0.04 0.07 0.5 C3 0.05 3 1.2 12 17.5 0.015 <0.04 0.06 0.35 C4 0.05 2.5 1.2 12 17.0 0.05 <0.04 0.06 0.35

AS est un acier standard utilisé couramment pour la fabrication de réacteurs ou d'élément de réacteurs. Les aciers F1, D1 et D2 sont également présentés à titre comparatif.AS is a standard steel commonly used for the manufacture of reactors or reactor components. Steels F1, D1 and D2 are also presented for comparison.

Exemple 1:Example 1:

Différents alliages ont été testés dans un réacteur de déshydrogénation de l'isobutane. La réaction de déshydrogénation de l'isobutane permet d'obtenir de l'isobutène. Une réaction secondaire est la formation de coke. Aux températures utilisées pour la déshydrogénation de l'isobutane, le dépôt de coke est principalement constitué de coke d'origine catalytique.Different alloys have been tested in an isobutane dehydrogenation reactor. The isobutane dehydrogenation reaction makes it possible to obtain isobutene. A side reaction is the formation of coke. At the temperatures used for the dehydrogenation of isobutane, the coke deposit consists mainly of coke of catalytic origin.

L'acier F1 présente une structure ferritique, les aciers C1 et C2 une structure austéno-ferritique et les aciers C3 et C4 une structure austénitique. Les teneurs en chrome et nickel des aciers C3 et C4 ont été ajustées en utilisant les coefficients d'équivalence de Guiraldenq et Pryce, afin de situer ces aciers dans le domaine monophasé austénitique du diagramme de Schaeffer.The steel F1 has a ferritic structure, the steels C1 and C2 an austeno-ferritic structure and the steels C3 and C4 an austenitic structure. The chromium and nickel contents of steels C3 and C4 were adjusted using the equivalence coefficients of Guiraldenq and Pryce, in order to locate these steels in the austenitic single-phase domain of the Schaeffer diagram.

Les alliages C1, C2, C3 et C4 ont la faculté de développer une couche d'oxyde stable et inerte vis-à-vis des phénomènes de cokage catalytique. La présence de silicium dans ces alliages favorise la formation d'une couche externe et sensiblement continue pratiquement constituée uniquement d'oxyde de chrome sans oxydes spinelles Cr_Ni_Fe. Cette couche d'oxyde de chrome est séparée du substrat métallique par une zone d'oxyde riche en silicium. L'atmosphère de la réaction chimique, par exemple de déshydrogénation de l'isobutane, est alors pratiquement uniquement en contact avec une couche d'oxyde de chrome inerte catalytiquement vis-à-vis du phénomène de cokage.Alloys C1, C2, C3 and C4 have the ability to develop a stable and inert oxide layer vis-à-vis catalytic coking phenomena. The presence of silicon in these alloys promotes the formation of an outer and substantially continuous layer practically consisting solely of chromium oxide without Cr_Ni_Fe spinel oxides. This chromium oxide layer is separated from the metal substrate by an oxide zone rich in silicon. The atmosphere of the chemical reaction, for example of dehydrogenation of isobutane, is then practically only in contact with a chromium oxide layer catalytically inert vis-à-vis the coking phenomenon.

Le protocole opératoire utilisé pour la réalisation des essais est le suivant :

  • Les échantillons d'acier sont découpés par électro-érosion puis polis au papier SiC # 180 pour assurer un état de surface standard et enlever la croûte d'oxyde qui a pu se former lors du découpage.
  • Un dégraissage dans un bain de CCl4, acétone puis éthanol est effectué.
  • Les échantillons sont ensuite suspendus au bras d'une thermobalance.
  • Le réacteur tubulaire est ensuite fermé La montée en température est réalisée sous argon.
  • Le mélange réactionnel constitué d'isobutane, d'hydrogène et d'argon et environ 300 ppm d'oxygène est injecté dans le réacteur.
The operating protocol used for carrying out the tests is as follows:
  • The steel samples are cut by electro-erosion and then polished with SiC # 180 paper to ensure a standard surface finish and remove the oxide crust that may have formed during cutting.
  • Degreasing in a CCl 4 , acetone then ethanol bath is carried out.
  • The samples are then suspended from the arm of a thermobalance.
  • The tubular reactor is then closed. The temperature rise is carried out under argon.
  • The reaction mixture consisting of isobutane, hydrogen and argon and approximately 300 ppm of oxygen is injected into the reactor.

La microbalance permet de mesurer en continu la gain de masse sur l'échantillon.The microbalance makes it possible to continuously measure the gain in mass on the sample.

La figure 1 montre un graphique ayant en abscisses le temps en heures et en ordonnées la masse de coke qui se forme sur l'échantillon en cours de réaction, masse donnée en gramme par mètre carré (g/m2). La courbe 1 est relative à l'acier AS, la courbe 2 à l'acier F1, les courbes 3 et 3b respectivement aux aciers D1 et D2, l'ensemble des courbes 4 aux aciers C1, C2, C3 et C4.FIG. 1 shows a graph having the time in hours on the abscissa and the ordinate the mass of coke which forms on the sample during the reaction, mass given in grams per square meter (g / m 2 ). Curve 1 relates to AS steel, curve 2 to F1 steel, curves 3 and 3b respectively to steels D1 and D2, all 4 curves to steels C1, C2, C3 and C4.

Il est clair que pour les aciers C1, C2, C3 et C4 selon l'invention le taux de cokage est réduit. Dans les mêmes conditions, les aciers F1, D1 et D2 montrent une moins bonne résistance au cokage.It is clear that for steels C1, C2, C3 and C4 according to the invention the coking rate is reduced. Under the same conditions, steels F1, D1 and D2 show poorer resistance to coking.

La figure 2 montre les courbes de cokage lors de plusieurs cycles de cokage/décokage successifs. Les décokages ont été réalisés sous air à 600°C, pendant le temps nécessaire pour brûler le coke déposé (de 5 à 10 minutes). La courbe 6 représente le cokage pour l'acier AS au premier cycle, la courbe 5 représente le cokage pour l'échantillon d'acier AS après 20 cycles de cokage/décokage.Figure 2 shows the coking curves during several successive coking / decoking cycles. The decoking was carried out in air at 600 ° C, for the time necessary to burn the deposited coke (5 to 10 minutes). Curve 6 represents coking for AS steel in the first cycle, curve 5 represents coking for AS steel sample after 20 coking / decoking cycles.

Les courbes 7 représentent les courbes de cokage/décokage après 20 cycles pour les aciers C3 et C4.Curves 7 represent the coking / decoking curves after 20 cycles for steels C3 and C4.

Après 20 cycles de cokage/décokage, les aciers C3 et C4 ont la même résistance vis-à-vis du cokage. Leur couche d'oxyde de chrome superficielle n'a pas évolué et elle a conservé sa très faible activité catalytique originelle vis-à-vis du cokage. Par contre, pour l'acier standard qui ne contient pratiquement pas de silicium, après 20 cycles de cokage/décokage, le taux de dépôt de carbone au bout de 6 heures d'essai a été multiplié par quatre. La couche protectrice de l'acier standard n'est pas stable: lors des décokages successifs, il se produit un enrichissement de cette couche en élément métallique catalytique comme le fer ou le nickel.After 20 coking / decoking cycles, steels C3 and C4 have the same resistance to coking. Their surface chromium oxide layer has not evolved and it has retained its very low original catalytic activity with regard to coking. On the other hand, for standard steel which contains practically no silicon, after 20 coking / decoking cycles, the carbon deposition rate after 6 hours of testing has been multiplied by four. The protective layer of standard steel is not stable: during successive decoking, there is an enrichment of this layer with catalytic metallic element such as iron or nickel.

Exemple 2:Example 2:

Un second test a été effectué avec une réaction de vapocraquage de l'hexane à une température d'environ 850°C. Le protocole de préparation des échantillons d'acier et de test est le même que pour l'exemple 1.A second test was carried out with a steam cracking reaction of hexane at a temperature of about 850 ° C. The protocol for preparing the steel samples and for testing is the same as for Example 1.

La figure 3 montre le cokage d'un échantillon d'acier AS, représenté par la courbe 8, nettement supérieure aux courbes 9 et 10 représentant respectivement le cokage des échantillons d'aciers C4 et C3.FIG. 3 shows the coking of a steel sample AS, represented by curve 8, clearly superior to curves 9 and 10 representing respectively the coking of samples of steels C4 and C3.

Pour ce second test, les alliages C3 et C4 qui contiennent notamment du silicium ont un taux de cokage inférieur à celui des aciers standards.For this second test, the C3 and C4 alloys which contain in particular silicon have a lower coking rate than that of standard steels.

Il faut noter les bonnes caractéristiques mécaniques en température des aciers C3 et C4 selon l'invention: -1- -2- -3- -4- -5- -6- -7- T Re Rm A trup trup t1% 10000 100000 10000 (°C) (MPa) (MPa) (%) (MPa) (MPa) (MPa) 600 140 370 40 210 150 140 700 130 320 44 75 30 50 800 120 300 50 15 7,5 8 The good mechanical temperature characteristics of the C3 and C4 steels according to the invention should be noted: -1- -2- -3- -4- -5- -6- -7- T Re Rm AT t rup t rup t 1% 10,000 100,000 10,000 (° C) (MPa) (MPa) (%) (MPa) (MPa) (MPa) 600 140 370 40 210 150 140 700 130 320 44 75 30 50 800 120 300 50 15 7.5 8

La colonne 1 correspond à la température de l'échantillon, la colonne 2 à la contrainte à la limite élastique, la colonne 3 à la contrainte à la rupture, la colonne 4 à l'allongement à la rupture. La colonne 5 correspond à la contrainte à la rupture en test de fluage après 10000 heures, la colonne 6 après 100000 heures, et la colonne 7 à la contrainte pour un allongement de 1% en test de fluage après 10000 heures.Column 1 corresponds to the temperature of the sample, column 2 to the stress at the elastic limit, column 3 to the stress at break, column 4 to the elongation at break. Column 5 corresponds to the breaking stress in the creep test after 10,000 hours, column 6 after the 100,000 hours, and column 7 to the stress for an elongation of 1% in the creep test after 10,000 hours.

Claims (11)

  1. A steel with improved resistance to coking,
    characterized in that it essentially has the following composition by weight:
    - about 0.05% or about 0.06% of carbon;
    - 2.5% to 5% of silicon;
    - 10% to 20% of chromium;
    - 10% to 15% of nickel;
    - 0.5% to 1.5% of manganese;
    - at most 0.8% of aluminium;
    - optionally 0.25% to 0.5% of titanium;
    - the complement to 100% being iron and unavoidable impurities.
  2. A steel according to claim 1
    characterized in that it essentially has the following composition by weight:
    - about 0.06% of carbon;
    - about 3.5% to 5% of silicon;
    - about 17.5% of chromium;
    - about 10% of nickel;
    - about 1.2% of manganese;
    - about 0.5% of titanium; and
    - about 0.07% of aluminium;
    - the complement to 100% being iron and unavoidable impurities.
  3. A steel according to claim 2, with an austeno-ferritic structure.
  4. A steel according to claim 1
    characterized in that it contains the following composition by weight:
    - 0.05% of carbon;
    - 2.5% to 3% of silicon;
    - 17% to 17.5% of chromium;
    - 12% of nickel;
    - 1.2% of manganese;
    - 0.35% of titanium; and
    - 0.06% of aluminium;
    - the complement to 100% being iron and unavoidable impurities.
  5. A steel according to claim 4, with an austenitic structure.
  6. A process for the manufacture of elements for units
    for petrochemical processes carried out at temperatures of between 350°C and 1100°C characterized in that, to improve the resistance of these elements to coking, they are manufactured entirely or partially from a steel according to any one of claims 1 to 5.
  7. A process according to claim 6, characterized in that said elements are manufactured entirely from said steel.
  8. A process according to any one of claims 6 and 7,
    characterized in that internal walls of elements of said units are covered with said steel after assembly thereof.
  9. A process according to claim 8, characterized in that coating is effected using at least one technique selected from co-centrifuging, plasma, electrolytic coating and overlay techniques.
  10. A process according to any one of claims 6 to 9,
    characterized in that the unit is an isobutane dehydrogenation unit operating at 550-700°C.
  11. A process according to any one of claims 6 to 9,
    characterized in that the unit is a naphtha, ethane or gas oil steam cracking unit operating at between 750°C and 1100°C.
EP95402864A 1994-12-20 1995-12-18 Anti-coking steels Expired - Lifetime EP0718415B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9415453A FR2728271A1 (en) 1994-12-20 1994-12-20 ANTI-COKAGE STEEL
FR9415453 1994-12-20

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EP0718415A1 EP0718415A1 (en) 1996-06-26
EP0718415B1 true EP0718415B1 (en) 2001-09-19

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AU2001267204A1 (en) * 2000-06-08 2001-12-17 Surface Engineered Products Corporation Coating system for high temperature stainless steel
US6824883B1 (en) * 2000-09-12 2004-11-30 Nova Chemicals (International) S.A. Surface on a stainless steel matrix
FR2819526B1 (en) * 2001-01-15 2003-09-26 Inst Francais Du Petrole USE OF AUSTENITIC STAINLESS STEELS IN APPLICATIONS REQUIRING ANTI-COCKING PROPERTIES
FR2833020B1 (en) * 2001-11-30 2004-10-22 Inst Francais Du Petrole USE OF QUASI-CRYSTALLINE ALUMINUM ALLOYS IN REFINING AND PETROCHEMICAL APPLICATIONS
FR2851774B1 (en) 2003-02-27 2006-08-18 Inst Francais Du Petrole LOW-ALLOY ANTICOKAGE STEELS WITH INCREASED SILICON AND MANGANESE CONTENT, AND THEIR USE IN REFINING AND PETROCHEMICAL APPLICATIONS
DE102005061626A1 (en) 2005-12-21 2007-06-28 Basf Ag Continuous heterogeneous catalyzed partial dehydrogenation of hydrocarbon involves feeding hydrocarbon to reaction chamber enclosed by shell made of specific steel, passing hydrocarbon through catalyst bed and dehydrogenating feed
US9272256B2 (en) 2011-03-31 2016-03-01 Uop Llc Process for treating hydrocarbon streams
KR101603455B1 (en) 2011-09-30 2016-03-14 유오피 엘엘씨 Process and apparatus for treating hydrocarbon streams
CN106399990B (en) * 2016-08-16 2019-09-20 深圳市诚达科技股份有限公司 A kind of anti-coking nano material and preparation method thereof based on stainless steel surface

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* Cited by examiner, † Cited by third party
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JPS5129854B2 (en) * 1973-04-21 1976-08-27
DE2458213C2 (en) * 1973-12-22 1982-04-29 Nisshin Steel Co., Ltd., Tokyo Use of an oxidation-resistant austenitic stainless steel
US4102225A (en) * 1976-11-17 1978-07-25 The International Nickel Company, Inc. Low chromium oxidation resistant austenitic stainless steel
JPS61113748A (en) * 1984-11-09 1986-05-31 Hitachi Ltd Fe-cr-ni-al-si alloy having resistance to sulfurization corrosion
JPH0627306B2 (en) * 1988-12-08 1994-04-13 住友金属工業株式会社 Heat resistant steel for ethylene cracking furnace tubes
US4999159A (en) * 1990-02-13 1991-03-12 Nisshin Steel Company, Ltd. Heat-resistant austenitic stainless steel
US5223214A (en) * 1992-07-09 1993-06-29 Carondelet Foundry Company Heat treating furnace alloys

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ATE205889T1 (en) 2001-10-15
CN1132265A (en) 1996-10-02
US5693155A (en) 1997-12-02
RU2146301C1 (en) 2000-03-10
KR100391747B1 (en) 2003-10-22
NO955144D0 (en) 1995-12-18
JPH08218152A (en) 1996-08-27
EP0718415A1 (en) 1996-06-26
CN1080323C (en) 2002-03-06
FR2728271B1 (en) 1997-02-21
FR2728271A1 (en) 1996-06-21
NO314807B1 (en) 2003-05-26

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