EP0100197A1 - Pech aus Rückständen von katalytischen Crackprozessen und anderen Rückständen - Google Patents

Pech aus Rückständen von katalytischen Crackprozessen und anderen Rückständen Download PDF

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Publication number
EP0100197A1
EP0100197A1 EP83304179A EP83304179A EP0100197A1 EP 0100197 A1 EP0100197 A1 EP 0100197A1 EP 83304179 A EP83304179 A EP 83304179A EP 83304179 A EP83304179 A EP 83304179A EP 0100197 A1 EP0100197 A1 EP 0100197A1
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EP
European Patent Office
Prior art keywords
pitch
fraction
feedstock
carbon fibers
percent
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP83304179A
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English (en)
French (fr)
Inventor
Ghazi Dickakian
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
Exxon Research and Engineering Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by EI Du Pont de Nemours and Co, Exxon Research and Engineering Co filed Critical EI Du Pont de Nemours and Co
Publication of EP0100197A1 publication Critical patent/EP0100197A1/de
Withdrawn legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10C—WORKING-UP PITCH, ASPHALT, BITUMEN, TAR; PYROLIGNEOUS ACID
    • C10C3/00—Working-up pitch, asphalt, bitumen
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
    • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
    • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
    • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
    • D01F9/145—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues
    • D01F9/155—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues from petroleum pitch

Definitions

  • This invention pertains to an aromatic pitch containing a high liquid crystal (optically active) fraction, and more particularly to a pitch which can be directly spun into carbon fibers.
  • mesophase a structurally ordered optically anisotropic spherical liquid crystal
  • mesophase a structurally ordered optically anisotropic spherical liquid crystal
  • suitable feedstocks for carbon artifact manufacture, and in particular carbon fiber manufacture should have relatively low softening points and sufficient viscosity suitable for shaping and spinning into desirable articles and fibers.
  • feedstock for carbon artifact manufacture Another important characteristic of the feedstock for carbon artifact manufacture is its rate of conversion to a suitable optically anisotropic material.
  • 350°C is the minimum temperature generally required to produce mesophase from a carbonaceous pitch.
  • at least one week of heating is necessary to produce a mesophase content of about 40%, at that minimum temperature.
  • Mesophase of course, can be generated in shorter times by heating at higher temperatures.
  • incipient coking and other undesirable side reactions take place at temperatures in excess of about 440 o C.
  • Cat cracker bottoms like all other heavy aromatic residues obtained from steam cracking, fluid cracking or coal processing are composed of two components: (1) a low molecular weight oil fraction which can be distilled? -and (2) an undistillable fraction of high molecular weight.
  • This high molecular weight fraction is insoluble in paraffinic solvents such as n-heptane, iso-octane, pet ether, etc. This fraction is generally called "asphaltene".
  • asphaltene-free feed for the production of pitches.
  • These asphaltenes have a very high molecular weight (up to 10,000), a very high coking characteristic (coking value as high as 67.5 wt% coke yield at 550 0 C), and a very high melting point (200-250°C) .
  • asphaltene-free cat cracker bottom is free of ash, coke particles and other impurities.
  • the absence of asphaltene, ash, coke particles and other organic and inorganic impurities make the cat cracker bottom distillate an ideal feed for the production of an aromatic pitch with a very high content of liquid crystals.
  • This asphaltene-free cat cracker bottom can be prepared by two methods: (a) by a distillation process; e.g., vacuum or steam distillation; and (b) by deasphaltenation of the cat cracker bottom.
  • the deasphaltenation can be made readily by solvent extraction with a paraffinic solvent.
  • the present invention uses deasphaltenated feedstock fractions to provide a pitch having a high Ti content, and one which does not require Ti solvent extraction prior to spinning into fibers.
  • the deasphaltenated fractions of a feedstock in accordance with this invention is generally free of ash and impurities, and has the proper rheological properties to allow direct spinning into carbon fibers.
  • the pitch obtained from this fraction produces fibers which have high strength and performance.
  • a deasphaltenated cat cracker bottom fraction obtained in accordance with the present invention has virtually no coking value at 550°C compared with a 56% standard coking value for Ashland 240.
  • the deasphaltenated cat cracker bottom fraction is composed of 4, 5, and 6 polycondensed aromatic rings. This provides a uniform feed material which can be carefully controlled to produce a uniform product with a narrow molecular weight distribution.
  • the present invention pertains to a high Ti pitch for direct spinning into carbon fibers.
  • An aromatic pitch with a very high liquid crystal fraction (80-100%) can be prepared by thermally reacting a deasphaltenated fraction of either a cat cracker bottom, steam cracker tar or a coal distillate, that are respectively rich in (4, 5 and 6); (2, 3, 4 and 5); and (3, 4, 5 and 6) aromatic rings.
  • the various feedstocks fraction are heat soaked in a temperature range from 420°C to 450°C at atmospheric pressure, and then vacuum stripped to remove at least a portion of the unreacted oils at a temperature in the approximate range of from 3200C to 440 0 C at 0.1 to 100 mmHg, and preferably at greater than 400°C at 1.0 - 5.0 mmHg of pressure.
  • the fraction in the case of cat cracker bottoms the fraction is heat soaked at approximately 440°C for 2-4 hours at atmospheric pressure. In the case of steam cracker tars, the fraction is heat soaked at 430°C for approximately 4.0 hours; and in the case of coal distillate, the fraction is heat soaked at approximately 440°C for 1/4 to 1/2 hour. All the heat soaked materials are then vacuum stripped and spun directly into carbon fibers.
  • the pitch of this invention is definable only in terms of deasphaltenated fractions of a feedstock and containing 4, 5 and 6 aromatic rings.
  • deasphaltenated feedstock and/or “deasphaltenated middle fraction of a feedstock” shall mean: a deasphaltenated material obtained from a middle cut of a feedstock, and/or one caused to be relatively free of asphaltenes by means of obtaining a distillate portion of said feedstock which when further treated will form a precursor which can be spun into a carbon fiber and which has the following general characteristics:
  • a typical weight percentage of asphaltenes in a deasphaltenated cat cracker bottom feedstock being in the range of approximately 0.0 to 1.0%.
  • a directly spinnable pitch of this invention has the proper rheological properties characterized as a glass transition temperature (Tg) in the approximate range of 180°C to 250°C at atmospheric pressure, and/ or a viscosity of less than approximately 2,500 cps in a temperature of approximately 360 0 C at atmospheric pressure.
  • Tg glass transition temperature
  • catalytic cracking refers to a thermal and catalytic conversion of gas oils, particularly virgin gas oils, boiling generally between 316°C and 566°C, into lighter, more valuable products.
  • Cat cracker bottoms refer to that fraction of the product of the cat cracking process which boils in the range of from about 200°C to about 550°C.
  • Cat cracker bottoms typically have relatively low aromaticity as compared with graphitizable isotropic carbonaceous pitches suitable in carbon artifact manufacture.
  • the cat cracker bottoms are fractionally distilled by heating the cat cracker bottom to elevated temperatures and reduced pressures, for example, by heating to temperatures in the range of 200°C to 300°C at pressures ranging from about 250 to 500 millimeters of mercury.
  • the cat cracker bottom is separated .into at least a single distillate having a boiling point at 760 mm mercury in the range of from about 250oC to about 530°C, and the residue being the fraction not distillable at temperatures up to 530 o C, at a pressure of about 350 to 450 millimeters of mercury.
  • the distillate fraction of the cat cracking bottom which is employed in forming a suitable carbonaceous pitch for carbon artifact manufacture is that fraction boiling in the approximate range of about 450°C to about 510°C at 760 mm of mercury.
  • the desired cat cracker bottom fraction can also be obtained by other commercially known separation methods such as steam distillation, flash stripping or by using a thin film evaporator.
  • the cat cracker bottom fraction is heat soaked at temperatures in the approximate range of 420°C to 450°C at atmospheric pressure. In general, heat soaking is conducted for times ranging from 2 hours to about 4 hours. In the practice of the present invention, it is particularly preferred that heat soaking be done in an atmosphere such as nitrogen, or alternatively in a hydrogen atmosphere.
  • the reaction mixture is then subjected to a reduced pressure at a liquid temperature between 320-440°C, and most preferably at 400-430 o C, to remove from the mixture at least part of the distillable unreacted oils.
  • a liquid temperature between 320-440°C, and most preferably at 400-430 o C
  • all of the unreacted oils are removed in order to concentrate and increase the anisotropic liquid crystal fraction in the final pitch product.
  • the use of a high liquid temperature, e.g., 400-430°C is very desirable.
  • the high liquid temperature helps to remove the distillable unreacted oils, which if left in the final pitch product tend to dilute and reduce the liquid crystal content of the pitch.
  • the heat soaked mixture can be purged with a gas such as nitrogen in order to accelerate the removal of the unreacted oils.
  • the resultant pitch produced by the above- described method has a low melting point (as defined by our DSC method) (190-230°C), has very high aromaticity (85-90% of aromatic carbon atoms by carbon NMR method) and contains a high anisotropic liquid crystal fraction (80-100% by polarized light microscopy).
  • the pitch composition is defined readily by using solvent analysis, wherein the content insolubles in toluene at room temperature and the content insolubles in quinoline at 75°C are determined.
  • the toluene insoluble (Ti) fraction in the pitch can be used to give a measure of the- liquid crystal content in the pitch.
  • One of the objectives of this invention is to transform the cat cracker bottom distillate fraction into a pitch with a very high content of toleune insolubles (80-100%), and which can be spun- directly into carbon fibers, as shown in Figure 1..
  • the pitch of this invention is definable in terms of deasphaltenated fractions of a feedstock ( Figure 1).
  • pitches used for direct spinning are of great importance to obtain good spinnability. It is desired to have pitches with low viscosity at the spinning temperature which is preferrably below around 400 o C , in order to avoid pitch cracking and volatilization which could lead to serious foaming of the fiber and substantial reduction in the fiber strength.
  • the pitch for direct spinning is also desired to be less sensitive to heat, i.e. does not change its viscosity too much when changing temperature. The sensitivity of the pitch to temperature variation can be determined from viscosity - temperature curves. This relationship for several pitches designated A, B, C, and D is shown in Figure 2.
  • Differential Scanning Calorimetry is used to obtain information on glass transition and softening characteristics of pitches.
  • An OMINITHERM Corp.- DSC Model (QC25) is used to obtain the glass transition (Tg) data.
  • the method comprises heating a small sample of the pitch in the DSC pan, allowed to cool and the DSC trace was then obtained by heating at the rate of 10°C/min under nitrogen (30cc/min). From the DSC trace three DSC data points are determined; the onset of Tg (Ti), the termination of Tg (Tf) and the Tg point which is at the midway between the Ti and Tf point. It has been reported that there is a relationship between the Tg of the pitch and its softening point as determined by the traditional method such as the ring and ball method. The softening point is higher by around 60 0 C than the Tg.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Textile Engineering (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Working-Up Tar And Pitch (AREA)
  • Inorganic Fibers (AREA)
EP83304179A 1982-07-19 1983-07-19 Pech aus Rückständen von katalytischen Crackprozessen und anderen Rückständen Withdrawn EP0100197A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US39975082A 1982-07-19 1982-07-19
US399750 1982-07-19

Publications (1)

Publication Number Publication Date
EP0100197A1 true EP0100197A1 (de) 1984-02-08

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP83304179A Withdrawn EP0100197A1 (de) 1982-07-19 1983-07-19 Pech aus Rückständen von katalytischen Crackprozessen und anderen Rückständen

Country Status (4)

Country Link
EP (1) EP0100197A1 (de)
JP (1) JPS5933386A (de)
AU (1) AU558441B2 (de)
CA (1) CA1207264A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7575026B2 (en) 2005-11-21 2009-08-18 Voith Patent Gmbh Paper machine mesh
CN113680301A (zh) * 2021-07-23 2021-11-23 东华大学 一种可纺中间相沥青的制备方法及装置

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4086156A (en) * 1974-12-13 1978-04-25 Exxon Research & Engineering Co. Pitch bonded carbon electrode
US4184942A (en) * 1978-05-05 1980-01-22 Exxon Research & Engineering Co. Neomesophase formation
US4208267A (en) * 1977-07-08 1980-06-17 Exxon Research & Engineering Co. Forming optically anisotropic pitches
US4219404A (en) * 1979-06-14 1980-08-26 Exxon Research & Engineering Co. Vacuum or steam stripping aromatic oils from petroleum pitch
US4271006A (en) * 1980-04-23 1981-06-02 Exxon Research And Engineering Company Process for production of carbon artifact precursor
EP0056338A1 (de) * 1981-01-14 1982-07-21 E.I. Du Pont De Nemours And Company Verfahren zur Herstellung von Pech, geeignet zur Darstellung von Gegenständen aus Kohle
EP0087749A1 (de) * 1982-02-23 1983-09-07 Mitsubishi Oil Company, Limited Pech als Rohstoff zur Herstellung von Kohlenstoffäden und Verfahren zur Herstellung derselben

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4086156A (en) * 1974-12-13 1978-04-25 Exxon Research & Engineering Co. Pitch bonded carbon electrode
US4208267A (en) * 1977-07-08 1980-06-17 Exxon Research & Engineering Co. Forming optically anisotropic pitches
US4184942A (en) * 1978-05-05 1980-01-22 Exxon Research & Engineering Co. Neomesophase formation
US4219404A (en) * 1979-06-14 1980-08-26 Exxon Research & Engineering Co. Vacuum or steam stripping aromatic oils from petroleum pitch
US4271006A (en) * 1980-04-23 1981-06-02 Exxon Research And Engineering Company Process for production of carbon artifact precursor
EP0056338A1 (de) * 1981-01-14 1982-07-21 E.I. Du Pont De Nemours And Company Verfahren zur Herstellung von Pech, geeignet zur Darstellung von Gegenständen aus Kohle
EP0087749A1 (de) * 1982-02-23 1983-09-07 Mitsubishi Oil Company, Limited Pech als Rohstoff zur Herstellung von Kohlenstoffäden und Verfahren zur Herstellung derselben

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7575026B2 (en) 2005-11-21 2009-08-18 Voith Patent Gmbh Paper machine mesh
CN113680301A (zh) * 2021-07-23 2021-11-23 东华大学 一种可纺中间相沥青的制备方法及装置
CN113680301B (zh) * 2021-07-23 2022-05-31 东华大学 一种可纺中间相沥青的制备方法及装置

Also Published As

Publication number Publication date
AU1695383A (en) 1984-01-26
CA1207264A (en) 1986-07-08
AU558441B2 (en) 1987-01-29
JPS5933386A (ja) 1984-02-23

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19880131

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Inventor name: DICKAKIAN, GHAZI