WO1980001568A1 - Fabrication de coke de petrole sans emission de fumees par cokefaction retardee - Google Patents

Fabrication de coke de petrole sans emission de fumees par cokefaction retardee Download PDF

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Publication number
WO1980001568A1
WO1980001568A1 PCT/US1980/000134 US8000134W WO8001568A1 WO 1980001568 A1 WO1980001568 A1 WO 1980001568A1 US 8000134 W US8000134 W US 8000134W WO 8001568 A1 WO8001568 A1 WO 8001568A1
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WO
WIPO (PCT)
Prior art keywords
feedstock
coke
chromic oxide
puffing
added
Prior art date
Application number
PCT/US1980/000134
Other languages
English (en)
Inventor
H Hsu
M Whittaker
L Grindstaff
Original Assignee
Great Lakes Carbon Corp
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 Great Lakes Carbon Corp filed Critical Great Lakes Carbon Corp
Priority to DE8080900362T priority Critical patent/DE3067079D1/de
Publication of WO1980001568A1 publication Critical patent/WO1980001568A1/fr

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Classifications

    • 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
    • C10B57/00—Other carbonising or coking processes; Features of destructive distillation processes in general
    • C10B57/04—Other carbonising or coking processes; Features of destructive distillation processes in general using charges of special composition
    • C10B57/06—Other carbonising or coking processes; Features of destructive distillation processes in general using charges of special composition containing additives
    • 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

  • Electrode grade graphite is manufactured from a commercial grade of coke having an acicular, anisotropic microstructure called needle coke, see U.S. 2,775,549 to Shea, Dec. 25, 1956, Cl. 201-42, made by delayed coking of certain petroleum residues under specific conditions of heat and pressure.
  • To produce graphite from such coke it is necessary to heat it to a temperature in the range of 2000-3000oC, which has the dual function of supplying energy for the conversion of the carbon in the coke to the graphitic crystalline form and of volatilizing impurities.
  • carbon bodies made from such cokes are heated at temperatures in the vicinity of 1000-2000oC, various sulfur-containing compounds decompose, attended by a rapid and irreversible expansion of the carbon body. This phenomenon is termed "puffing".
  • puffing is extremely undesirable as it may destroy the structural integrity of the piece and render it marginal or useless for its intended purpose.
  • Puffing of a carbon article made from high sulfur cokes generally starts at about 1500oC, and may result in a volumetric expansion of as much as 25%. It is not simply an elastic expansion but should be characterized as an inelastic, irreversible expansion.
  • the generally accepted explanation of the puffing phenomenon is that in acicular needle cokes with a relatively large amount of sulfur, sulfur atoms are bonded to carbon atoms by covalent bonds, either in carbon ring structures or linking rings. These bonds are less stable at high temperatures than the carbon-to-carbon bonds. On heating, the carbon-sulfur bonds rupture, the sulfur is freed, then reacts with hydrogen to form hydrogen sulfide. The simultaneous rupture of these bonds and evolution of hydrogen sulfide and other sulfur containing materials causes the physical expansion called puffing.
  • additives have usually been added during the mixing stage when various sizes and grades of coke particles are mixed, before being wetted with pitch, formed into the desired shape, baked at an intermediate temperature and graphitized at high temperatures.
  • Additives have included primarily metal salts and oxides, as disclosed in British 733,073, Greenhalgh, July 6, 1955, Cl. 90 b; French 1,491,497, Gillot et al. , Aug. 11, 1967, Cl. C 01 b; French 2,035,273, Continental Oil, Dec. 18, 1970, Cl. C 10 b 57; U.S. 3,642,962, Wallouch, Feb. 15, 1972, Cl.
  • French 2,035,273 discloses a low sulfur coke produced by the addition of 0.3-5% of sodium carbonate to the coking stream mixture and subsequent hydrogenation of the coke at high temperature.
  • British 733,073 discloses the use of oxides of chromium, iron, copper, or nickel incorporated in the grinding stage of coke, mixed with pitch, shaped, baked at 1200oC, and graphitized at 2500°-2800°C.
  • U.S. 3,563,705 discloses the use of mixtures of iron or calcium compounds with small amounts of titanium or zirconium compounds as puffing inhibitors incorporated into the coke-binder mixture.
  • U.S. 3,338,993 discloses the use of calcium, magnesium, strontium, and barium fluorides as puffing inhibitors with raw or calcined coke and binder, mixed, shaped, baked and graphitized.
  • U.S. 3,642,962 discloses the use of 1-3% calcium cyanamid or calcium carbide as desulfurizing agents and puffing inhibitors, mixed with raw coke prior to calcining.
  • CTE is also of vital importance in the production of graphite for certain applications. Electrodes for electric furnace melting of steel must have a low CTE to avoid excessive differential expansion at operating temperatures and the resultant spalling, which in turn causes excessive consumption of the electrode and cost in operation. Other applications requiring dimensional stability at high temperatures are well-known although of somewhat less economic importance.
  • any foreign material to a graphitizing carbonaceous mix will have, in addition to its desired effect, such as puffing inhibition, the effect of increasing the CTE of the graphite body.
  • a needle coke is distinguished by its physical structure when microscopically examined, showing long needle-like acicular particles .
  • Such cokes to be suitable for manufacture of graphite electrodes to be used in ultra-high powered electric steel furnaces, should have a graphite CTE characteristic of less than 5 x 10 - 7 /o C measured over the range of 0o -50o C.
  • Needle cokes for lower powered electric steel furnaces may have a graphite CTE characteristic of as much as 7 x 10-7 /o C over the 0o -50o C range .
  • the blends of cokes must be thoroughly mixed to avoid the difficulties present in making uniform homogeneous blends and in thoroughly coating the particles, which are often as much as 7mm. in diameter, with the puffing inhibitor. Both of these difficulties can lead to non-uniform dispersion of the inhibitor and to puffing, even though there is sufficient inhibitor present in the total mix to prevent puffing.
  • the puffing problem is further increased with the rate of graphitization of the carbon bodies.
  • Optimum distribution of the inhibitor throughout the structure of the carbon body to be graphitized is essential as the degree of puffing for any coke particle blend is highly rate sensitive, being directly related to the rate of temperature increase during the graphitization cycle.
  • the figures in certain of the examples given will show a much higher dynamic puffing at a 14oC/min. temperature rise than for a 5oC/min. rise.
  • a petroleum coker feedstock which would normally produce a puffing coke due to its high sulfur content is rendered nonpuffing by the addition of a small quantity of a chromium compound, preferably chromic oxide, to the feedstock as a fine particle size powder.
  • a chromium compound preferably chromic oxide
  • the chromic oxide may be pre-dispersed in a high concentration in a small quantity of the feedstock (fresh feed or furnace feed) or compatible material miscible with the feedstock or dispersed in the total coker stream and added either batchwise to a batch type coker, or continuously to the main stream in a delayed coker.
  • a fine particle size chromic oxide 100% less than 5 micron and 70% less than 2 micron diameter, predispersed in a portion of the feedstock, insures that the final product will be a homogeneous coke with chromic oxide uniformly distributed throughout.
  • a current of inert gas or steam bubbled through the batch type coker during the run aids in keeping the chromic oxide in suspension without significantly increasing the CTE of the finished product during batchwise coking. In a commercial delayed coker this is not essential.
  • delayed coking reference is made to an article by R.J. Diwoky, Continuous Coking of Residuum by the Delayed Coking Process, Refiner and Natural Gasoline Manufacturer, Vol. 17, No. 11, Nov. 1938.
  • the present invention involves the use of this type of coking operation.
  • Cr 2 O 3 is the final product of calcination of numerous chromium compounds e.g., hydrated Cr(III) oxide, Cr (III) nitrate,
  • Cr 2 O 3 is manufactured commercially by ignition of compounds such as metal chromates and bichromates with reducing agents and may be produced in situ by reduction with the coke.
  • the reactive species may be elemental chromium, produced by reduction of the Cr 2 O 3 by the coke during the graphitization process, or by dissociation occurring at or below its melting point about (2275oC).
  • Ferrochromium alloys are produced by reduction of chromite ore with coke in a submerged arc furnace, and the similarity to the graphitization conditions makes this a definite possibility.
  • CTE of the graphitized coke was determined by preparing small 5/8" x 5" (1.6 x 12.7 cm.) electrodes by the procedure disclosed in U. S . patent 2 , 775, 549 , (except for calcination of the coke to 1250oC)C , and measuring their elongation over the temperature range of 0o to 50°C.
  • a decant oil the fractionater tower bottoms from a catalytically cracked gas oil fraction, also termed slurry oil, or other equivalent hydrocarbon residue, is conveyed from the fractionater 33 through line 10 and meter 14 to diversion valve 17, where a portion of the feedstock is diverted through valve 13, and meter 15 to disperser 18. Simultaneously a portion of chromic oxide 12 is weighed in scale 16 and conveyed to disperser 18 where it is dispersed in the feedstock to a specific concentration by weight. Alternately a compatible liquid and additives from supply 19 are metered through valve 11 to valve 13 and meter 15 to disperser 18.
  • a compatible liquid and additives from supply 19 are metered through valve 11 to valve 13 and meter 15 to disperser 18.
  • the chromic oxide is dispersed and discharged through line 22 and meter 23 to mixer 24 where it is mixed with the main portion of the feedstock coming through line 20 and meter 25, to the exact proportion desired.
  • the chromic oxide concentrate mixed with the feedstock is pumped by pump 27 through line 26 to furnace 29, then through line 31 to coker drums 28 and 28a, where it is conventionally delay coked.
  • the overheads are taken off through line 32 and sent to the fractionater 33.
  • the disperser which may be any of several types of equipment well known in the art, preferably a high shear or colloid mill. Alternately, a roller or ball mill could be used.
  • a dispersion of approximately 5-50% by wt. of chromic oxide in the feedstock is used as a concentrate.
  • the chromic oxide dispersion and feedstock are metered into the mixer 24 where they are mixed in the correct proportions to give a concentration of approximately 0.05-0.5 wt. % Cr 2 O 3 in the feedstock which is then pumped into the coker 28.
  • EXAMPLE 1 The micronized puffing inhibitor, chromic oxide, was mixed with samples of a fresh feed decant oil coker feedstock, at 0.1 wt. % level in a high speed blender for about 5 minutes. The mixtures were coked under identical conditions in 4 liter resin flasks. In an insulated glass resin flask, an inert gas at the rate of 0.16 SCFH/kg (4.5 l./hr./kg.) mixture was bubbled up from the bottom of the coking pot to keep the Cr 2 O 3 uniformly dispersed in feedstock. The following time-temperature cycle was used: Temperature Elapsed Time Rate ⁇ c°/hr
  • 530°C-RT Cool-down, power off Dynamic puffing (DP) of the cokes was then determined by the method below and compared with uninhibited samples, and with samples inhibited in the normal manner with dry-mixed iron oxide.
  • the coke samples had 50% ⁇ 200 mesh (78 mesh/cm.) particles and 100% ⁇ 65 mesh (26 mesh/cm.) particles.
  • DP was measured by taking representative samples by the method of ASTM D346-35, crushing, mixing 100 g coke and 25 g pitch, and molding plugs at 12,500 psi (879 kg./cm. 2 ). The plugs were measured by micrometer and placed in a dilatometer. The temperature was raised to 1200oC over a period of 50 ⁇ 10 min. The test was run at a temperature increase of 5o or 12-16oC/min. over the 1200o-2900oC range, with measurements taken every five minutes. The reported DP (dynamic puffing) is the maximum percentage of elongation (or shrinkage) measured. All of the DP's below were at 14oC/min. rise except as noted
  • micronized chromic oxide (0.1 wt. %) added to the feedstock inhibited puffing of the resulting coke without adversely affecting the CTE of the coke.
  • the CTE of the resulting coke (0.35% ash) was less than that of the coke with no inhibitor or conventionally inhibited with 1 pph iron oxide.
  • Micronized chromic oxide (0.075 wt. %) was dispersed in a sample of slurry oil coker feedstock. The mixture was then coked using the procedure of Example 1. The properties of the coke were determined for comparison with that of the control coke from this oil with and without the addition of micronized chromic oxide.
  • micronized chromic oxide added to the feedstock resulted in a coke (0.51% ash) with a substantial reduction in puffing without adversely affecting the CTE of the coke.
  • the CTE of the coke made in the presence of chromic oxide was slightly lower than that from the original untreated feedstock.
  • Micronized chromic oxide was added conventionally by dry mixing to a coke sample made from the decant oil of Example 1, to determine its relative effectiveness in a dry blend vs. addition to the coker feedstock, to an equal Cr 2 O 3 concentration on the coke basis with respect to puffing inhibition. Results were as follows:
  • Examples 1-5 above were made in 4 liter resin flasks and were agitated by nitrogen bubbling for one minute when the temperature reached 420oC No settling of chromic oxide was observed.
  • EXAMPLE 8 The same feedstock in Example 7 was processed in a 4 l. resin flask with 0.5 C.F.H. (14 l./hr.) N bubbled through the system during the temperature interval of 400o-450oC while the temperature was raised at a rate of 20o/hr, for a period of 2.5 hrs. Results of these tests are shown below: Cr 2 O 3 Add. Coke Ash Ash CTE DP Run No. to feedstock Yield Top Bot. 10 -7 /oC % ⁇ L
  • Coke to Feedstock (Composite) 5° C/min. 14o C/min.
  • Flask (The higher ash content of the sample prepared in the resin flask is probably due.to a slight pickup of silica from the flask. ) The favorable results obtained at the high upheat rates are notable.
  • Clarified Oil 0 0.10 2.30 3.0 4.4
  • the CTE of the cokes produced were excessive for premium needle cokes to be used in making ultra high power graphite electrodes.
  • the very high sulfur contents of the oils necessitated the high level of Cr 2 O 3 addition, which reduced puffing to a satisfactory level, but increased the CTE to a point above the acceptable range for such an application.
  • the cokes were suitable, however, for making graphite bodies and electrodes for less severe applications.
  • Some feedstocks may well need and be beneficially treated with Cr 2 O 3 additions of as much as 0.5%, resulting in a 2% ash level of Cr 2 O 3 in the final coke.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Carbon And Carbon Compounds (AREA)
  • Coke Industry (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

Abstract

De l'oxyde de chrome tres fin est disperse dans un materiau de coke de petrole a haute teneur en soufre (24) avant la cokefaction retardee (28, 28A) pour produire du coke aciculaire avec un faible CTE (coefficient d'expansion thermique) et un degagement negligeable de fumees lors du chauffage a la temperature de graphitisation.
PCT/US1980/000134 1979-02-02 1980-01-23 Fabrication de coke de petrole sans emission de fumees par cokefaction retardee WO1980001568A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE8080900362T DE3067079D1 (en) 1979-02-02 1980-01-23 Making non-puffing petroleum coke by delayed coking

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US883979A 1979-02-02 1979-02-02
US8839 1979-02-02

Publications (1)

Publication Number Publication Date
WO1980001568A1 true WO1980001568A1 (fr) 1980-08-07

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ID=21733978

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PCT/US1980/000134 WO1980001568A1 (fr) 1979-02-02 1980-01-23 Fabrication de coke de petrole sans emission de fumees par cokefaction retardee

Country Status (5)

Country Link
EP (1) EP0022854B1 (fr)
JP (1) JPS55501182A (fr)
CA (1) CA1135205A (fr)
DE (1) DE3067079D1 (fr)
WO (1) WO1980001568A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5215651A (en) * 1988-07-29 1993-06-01 Mitsubishi Kasei Corporation Process for producing coke

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6241284A (ja) * 1985-08-20 1987-02-23 Nisshin Steel Co Ltd 含クロムコ−クスの製造法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB733073A (en) * 1952-04-08 1955-07-06 Nat Res Dev Improvements in or relating to production of artificial graphite masses
US3873427A (en) * 1972-11-24 1975-03-25 Lummus Co Desulfurizing coke using a ferruginous material and a metal chloride
US4140623A (en) * 1977-09-26 1979-02-20 Continental Oil Company Inhibition of coke puffing

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1491497A (fr) * 1966-06-30 1967-08-11 Pechiney Prod Chimiques Sa Procédé pour la graphitation de produits carbonés

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB733073A (en) * 1952-04-08 1955-07-06 Nat Res Dev Improvements in or relating to production of artificial graphite masses
US3873427A (en) * 1972-11-24 1975-03-25 Lummus Co Desulfurizing coke using a ferruginous material and a metal chloride
US4140623A (en) * 1977-09-26 1979-02-20 Continental Oil Company Inhibition of coke puffing

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP0022854A4 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5215651A (en) * 1988-07-29 1993-06-01 Mitsubishi Kasei Corporation Process for producing coke

Also Published As

Publication number Publication date
CA1135205A (fr) 1982-11-09
EP0022854A4 (fr) 1981-08-27
EP0022854B1 (fr) 1984-03-21
DE3067079D1 (en) 1984-04-26
JPS55501182A (fr) 1980-12-25
EP0022854A1 (fr) 1981-01-28

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