CA2556482C - Process for producing pitches from coal, tars and distillates thereof by oxidative thermal treatment - Google Patents
Process for producing pitches from coal, tars and distillates thereof by oxidative thermal treatment Download PDFInfo
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- CA2556482C CA2556482C CA2556482A CA2556482A CA2556482C CA 2556482 C CA2556482 C CA 2556482C CA 2556482 A CA2556482 A CA 2556482A CA 2556482 A CA2556482 A CA 2556482A CA 2556482 C CA2556482 C CA 2556482C
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- thermal treatment
- pitch
- distillation
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- air
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- 238000007669 thermal treatment Methods 0.000 title claims abstract description 28
- 230000001590 oxidative effect Effects 0.000 title claims abstract description 11
- 239000003245 coal Substances 0.000 title claims abstract description 6
- 239000011295 pitch Substances 0.000 title claims description 50
- 238000000034 method Methods 0.000 title claims description 20
- 230000008569 process Effects 0.000 title claims description 20
- 239000011269 tar Substances 0.000 title claims description 17
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 14
- 239000001301 oxygen Substances 0.000 claims abstract description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 10
- 239000000203 mixture Substances 0.000 claims abstract description 10
- 239000003153 chemical reaction reagent Substances 0.000 claims abstract description 4
- MWPLVEDNUUSJAV-UHFFFAOYSA-N anthracene Chemical compound C1=CC=CC2=CC3=CC=CC=C3C=C21 MWPLVEDNUUSJAV-UHFFFAOYSA-N 0.000 claims description 56
- YNPNZTXNASCQKK-UHFFFAOYSA-N phenanthrene Chemical compound C1=CC=C2C3=CC=CC=C3C=CC2=C1 YNPNZTXNASCQKK-UHFFFAOYSA-N 0.000 claims description 8
- 238000004508 fractional distillation Methods 0.000 claims description 5
- 239000006227 byproduct Substances 0.000 claims description 4
- 238000004821 distillation Methods 0.000 abstract description 24
- 238000004519 manufacturing process Methods 0.000 abstract description 12
- 239000011280 coal tar Substances 0.000 abstract description 6
- 230000008901 benefit Effects 0.000 abstract description 4
- 230000007613 environmental effect Effects 0.000 abstract description 3
- 230000036541 health Effects 0.000 abstract description 3
- 239000002243 precursor Substances 0.000 abstract description 2
- 239000003570 air Substances 0.000 abstract 1
- 230000001747 exhibiting effect Effects 0.000 abstract 1
- 239000003921 oil Substances 0.000 description 27
- 238000006243 chemical reaction Methods 0.000 description 20
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 18
- SMWDFEZZVXVKRB-UHFFFAOYSA-N Quinoline Chemical compound N1=CC=CC2=CC=CC=C21 SMWDFEZZVXVKRB-UHFFFAOYSA-N 0.000 description 14
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 11
- 229910052799 carbon Inorganic materials 0.000 description 9
- 239000000047 product Substances 0.000 description 9
- 238000001914 filtration Methods 0.000 description 7
- 239000002994 raw material Substances 0.000 description 7
- 239000011347 resin Substances 0.000 description 7
- 229920005989 resin Polymers 0.000 description 7
- 235000002918 Fraxinus excelsior Nutrition 0.000 description 6
- UFWIBTONFRDIAS-UHFFFAOYSA-N Naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 6
- 125000003118 aryl group Chemical group 0.000 description 6
- 239000002956 ash Substances 0.000 description 6
- GVEPBJHOBDJJJI-UHFFFAOYSA-N fluoranthene Chemical compound C1=CC(C2=CC=CC=C22)=C3C2=CC=CC3=C1 GVEPBJHOBDJJJI-UHFFFAOYSA-N 0.000 description 6
- 239000007787 solid Substances 0.000 description 6
- UJOBWOGCFQCDNV-UHFFFAOYSA-N 9H-carbazole Chemical compound C1=CC=C2C3=CC=CC=C3NC2=C1 UJOBWOGCFQCDNV-UHFFFAOYSA-N 0.000 description 4
- 239000003575 carbonaceous material Substances 0.000 description 4
- 238000009833 condensation Methods 0.000 description 4
- 230000005494 condensation Effects 0.000 description 4
- BBEAQIROQSPTKN-UHFFFAOYSA-N pyrene Chemical compound C1=CC=C2C=CC3=CC=CC4=CC=C1C2=C43 BBEAQIROQSPTKN-UHFFFAOYSA-N 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 239000004411 aluminium Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000000711 cancerogenic effect Effects 0.000 description 3
- 239000007833 carbon precursor Substances 0.000 description 3
- 239000003054 catalyst Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 238000007086 side reaction Methods 0.000 description 3
- 230000006641 stabilisation Effects 0.000 description 3
- 238000011105 stabilization Methods 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 2
- 238000003763 carbonization Methods 0.000 description 2
- 231100000315 carcinogenic Toxicity 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 239000000571 coke Substances 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000006482 condensation reaction Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 239000013067 intermediate product Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 125000005575 polycyclic aromatic hydrocarbon group Chemical group 0.000 description 2
- 150000003254 radicals Chemical class 0.000 description 2
- 239000010802 sludge Substances 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 208000005623 Carcinogenesis Diseases 0.000 description 1
- FMMWHPNWAFZXNH-UHFFFAOYSA-N ERM-AC051 Natural products C1=C2C3=CC=CC=C3C=C(C=C3)C2=C2C3=CC=CC2=C1 FMMWHPNWAFZXNH-UHFFFAOYSA-N 0.000 description 1
- 238000005727 Friedel-Crafts reaction Methods 0.000 description 1
- 208000003251 Pruritus Diseases 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 238000010420 art technique Methods 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 239000011305 binder pitch Substances 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000036952 cancer formation Effects 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 231100000357 carcinogen Toxicity 0.000 description 1
- 231100000504 carcinogenesis Toxicity 0.000 description 1
- 239000003183 carcinogenic agent Substances 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 238000006356 dehydrogenation reaction Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 125000001072 heteroaryl group Chemical group 0.000 description 1
- 125000005842 heteroatom Chemical group 0.000 description 1
- 125000000623 heterocyclic group Chemical group 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 150000002605 large molecules Chemical class 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000000399 optical microscopy Methods 0.000 description 1
- 230000037361 pathway Effects 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000004416 surface enhanced Raman spectroscopy Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 239000011299 tars and pitches Substances 0.000 description 1
- 238000013022 venting Methods 0.000 description 1
- 239000003039 volatile agent Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
Classifications
-
- 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
- C10C1/00—Working-up tar
- C10C1/04—Working-up tar by distillation
- C10C1/16—Winning of pitch
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Working-Up Tar And Pitch (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
The invention relates to the production of brea from distillates arising from high temperature coal tar having a distillation range of more than 260 ~C, by means of sequential and combined application of three stages in mild pressure and temperature conditions (<400~ C, <10 bar g): oxidative thermal treatment used as a reagent for air or oxygen, mixtures thereof, or air which is low in oxygen; thermal treatment in an inert atmosphere and fractionated distillation. It is possible to obtain brea exhibiting environmental advantages and advantages in term of occupational health, which can be used as coal precursors.
Description
PROCESS FOR PRODUCING PITCHES FROM COAL TARS AND DISTILLATES
THEREOF BY OXIDATIVE THERMAL TREATMENT
The invention relates to a process for producing pitches, in particular those suitable for use as carbon precursors, from coal tars and distillates thereof, through a sequential and combined operation in three steps:
1.- Reaction: Oxidative thermal treatment under mild conditions of pressure and temperature (<4000 C, <10 bar g, residence time in the range of 2-10 seconds, and preferably 350-400 C, 5-10 bar g, 6-10 seconds), using air, oxygen, low-oxygen air or mixtures thereof as reagents.
THEREOF BY OXIDATIVE THERMAL TREATMENT
The invention relates to a process for producing pitches, in particular those suitable for use as carbon precursors, from coal tars and distillates thereof, through a sequential and combined operation in three steps:
1.- Reaction: Oxidative thermal treatment under mild conditions of pressure and temperature (<4000 C, <10 bar g, residence time in the range of 2-10 seconds, and preferably 350-400 C, 5-10 bar g, 6-10 seconds), using air, oxygen, low-oxygen air or mixtures thereof as reagents.
2.- Thermal treatment under inert atmosphere (340-400 C, <10 bar g, residence time in the range of 3-10 hours, and preferably 370-400 C, atmospheric pressure, 4-6 hours) for stabilization of the reaction product.
3.- Fractional distillation (preferably in vacuum or by stripping with steam or inert gas) in order to adjust, according to the desired application, the softening point of the pitch or carbonaceous precursor.
BACKGROUND OF THE INVENTION
Pitches are mostly produced by distillation of coal tar. The tar, once dehydrated and after removal of a first light fraction of BTX (<5%), gives rise to the following fractions according to the different distillation cuts:
= Naphthalene oil fraction. Within a distillation range of less than 260 C
and with a naphthalene content greater than 50%, it represents approximately 20% of the parent tar and is used for the recovery of naphthalene of high commercial value as well as for the production of technical oils.
= Anthracene oil fraction. A complex mixture of polycyclic aromatic hydrocarbons within a distillation range of 260-400 C mainly formed by anthracene, phenanthrene, fluoranthene, pyrene and carbazole. It represents approximately 30% of the parent tar, and is a directly marketable product for the production of carbon black in strong competition with various petroleum residues. Also would be of commercial interest the conversion into pitch of the major portion of this fraction.
= Pitch. The largest product obtained from tar distillation. It is a black solid with a softening point of about 30-250 C, characterized by its content of substances insoluble in certain solvents such as toluene and quinoline. It is a complex mixture of polycyclic aromatic hydrocarbons with three or more condensed aromatic rings and represents approximately 50% of the parent tar. It is one of the raw materials employed in the manufacture of electrodes for aluminium and graphite industries.
Since the method for producing pitch consists only in the separation of oils until adjustment of the softening point of the pitch pre-existing in tar, its production can be regarded accordingly as a pure physical operation. Therefore, the quality of pitches obtained by prior art techniques is ruled by the quality of the tars present in the production process.
The characteristic fact that coal tar is a byproduct from coke batteries makes this raw material a highly inconsistent product, and this drawback is only compensable through the formulation of suitable tar blends. In any event, all types of tars and, consequently, pitches obtained thereby, have solid particles in suspension (primary and secondary QI, and carry-over), besides different types of metallic sludge identifiable by its ashes content. Both pollutants prejudice pitch quality and/or decrease its potential application in advanced carbon materials.
Anthracene oil is obtained along distillation of coal tar and is characterized by its distillation range, which is comprised from about 260 C until the corresponding temperature for adjusting the softening point of the pitch obtained as a final product (generally 400-410 C). Anthracene oil is mostly constituted by aromatic hydrocarbons of 2-4 benzene rings and the corresponding heterocyclics with 0, N and S, phenanthrene, anthracene, fluoranthene, carbazole and pyrene being the main components. High aromaticity of anthracene oil and the characteristic of being a distilled product and entirely distillable in its whole range, convert this product into a raw material of highly consistent quality, what suggests the possibility of more refined uses.
Many of the aromatic hydrocarbons present in anthracene oil and some heteroaromatic ones are transformed into anisotropic and graphitizable carbonaceous materials by means of slow thermal treatment up to 1000 C in a closed vessel duly pressurized for avoiding evaporation. Thermal treatment up to a lower temperature would halt transformation at an intermediate stage -the pitch- although with a low yield thereof.
The process consists of a dehydrogenating aromatic condensation which is generated by radical pathways. Said intermediate step for producing pitch still proceeds under excessively high temperatures and low conversion rates for proper application at industrial level. All this suggests the possibility of inducing aromatic condensation by means of catalytic reactions that promote generation of radicals, and their condensation and dehydrogenation at lower temperatures with a higher yield. Among the possible inductors for this type of reactions, the catalysts of Friedel-Craft (BF3/HF, AICI3) and sulfur are well known. For the quality of the final products or by reason of operation costs and residues/byproducts generated such catalysts are not advisable, thus proposing for this case, and constituting an objective of the present invention, the use of oxygen, air, low-oxygen air or mixtures thereof in the reactions.
The treatment with air of tars and pitches as well as composite materials, self syntherizable mesophase and fibers has been used actually for different purposes such as the increase of molecular weight and softening point of pitches and tars, the avoidance of swelling during carbonization in composite carbon/carbon materials and self-syntherizabie mesophase, and the thermal stabilization of fibers before carbonization.
Patent EP-A-4167046 discloses the production of a pitch with low content in solids by means of oxidation with air or oxygen of a distillation fraction selected from coal tar or a heavy oil derived thereof, while heated at preferred temperatures of 315-385 C, though the possibility of operating at a lower temperature (149 C) is mentioned, until obtaining a desired intermediate product. This intermediate product is then submitted to distillation by stripping with steam or an inert gas, although said distillation could be avoided by using higher temperatures in the oxidation phase. The result is an impregnating pitch especially useful in the manufacture of electrodes.
Patent US 4892642 discloses the production of pitches from coal tars in three steps : an oxidative thermal treatment by 350-400 C and 1-3 atm, a thermal treatment under inert atmosphere and a fractional distillation.
The possibility of introducing an intermediate thermal treatment in order to improve both the pitch quality (in rheological terms and fixed carbon) and final yielding is not regarded in said patent. The pressure conditions or the time required for the processing steps are also not mentioned in the patent.
DESCRIPTION OF THE INVENTION
The process according to the invention, in comparison with the prior art, starts with a wider range of raw materials, including petrochemical aromatic fractions.
Pitches obtained in accordance with the invention, when compared with those of the prior art, present a higher intrinsic quality and improved properties in relation to health (carcinogenesis) and environment.
The reaction of anthracene oil with the oxygen present in the air at temperatures lower than 4000 C and preferably higher than 350 C, produces a molecular condensation through mechanisms that, in view of the reactivity of the main components of anthracene oil, appear to be similar to those present when sulfur is used as catalyst.
There has been observed that parameters such as temperature, residence time, gas flow (air/oxygen) and charge and pressure of the reactor, have an effect on the reaction course by favoring or inhibiting the aromatic condensation reactions, which are critical for the formation of compatible molecular structures able to promote aromatic condensation reactions instead of polymerization and cross-linking reactions.
An additional thermal treatment under inert atmosphere enables to increase planarity of molecules and to stabilize the reaction product, in the sense of filtering possible side reactions, which further promotes its wettability, increases its graphitizability and generally improves the reaction yield.
Pitches produced according to the present invention exhibit a substantial reduction in carcinogenic components due to the limited presence thereof in anthracene oil and their reaction through the proposed conditions of operation. At the same time, the performance of fractional distillation in vacuum, together with the molecular weight distribution achieved by means of the selected conditions of operation, produce a pitch with a reduced volatility what means a substantial environmental benefit.
The reaction of anthracene oil with air generates only water as byproduct/effluent (slightly polluted with ammonia and equivalent in composition to the ammoniacal waters obtained during the tar distillation process) and a gaseous current that comprises low-oxygen air, CO and CO2. Since the pitch or carbonaceous material is free from solid particles and metallic sludge, the resulting product will not contain such stuff.
According to the selected conditions of reaction, the resulting pitch can generate cokes which when observed under optical microscopy with polarized light, can appear as 100% anisotropic or 100% isotropic, depending on the properties of the pitch receiving interest.
In view of the advantageous characteristics of the pitches obtained by the process of the invention, such pitches are suitable for applications belonging to the field of carbon precursors and in particular are useful in the manufacture of electrodes for aluminium industry, graphite electrodes and synthetic graphite in general, binders for refractory industry, waterproof materials and electrometallurgical paste.
Due to the low selectivity of the reaction, the unreacted anthracene oil may be directly put in commerce, in accordance with the usual applications of said raw material obtained by tar distillation. Additionally, the increase of anthracene/phenanthrene concentration, as a consequence of these being poorly reactive components, would 5 provoke that said fraction could promote the actual interest in the manufacture of anthracene paste.
During the process, three phenomenological situations derived from side reactions to avoid are generated:
1. Formation of cross-linked structures/gums.
2. Generation of solid particles.
3. Generation of high molecular weight structures.
The conditions for the process were determined with the purpose of avoiding the above-mentioned side reactions, while maximizing yield, economy and safety of the process. For that reason, the following parameters of operation were selected:
= Temperature: 250-400 C, preferably 350-400 C.
= Pressure: 5-10 bar g.
= Specific airflow (21% 02): 0.1-0.25 kg/kg of anthracene oil.
= Residence time during reaction: 2-10 seconds, preferably 6-10 seconds.
= Conversion in a single step: s40%. By means of successive transformation steps, net yields of 60% or more can be achieved.
= Thermal treatment under inert atmosphere: 340-400 C, 3-10 hours, 0-10 bar g, preferably 370-400 C, atmospheric pressure and 4-6 hours.
= Distillation up to softening point: According to the application. In the range of 85-250 C Mettler for conventional applications.
In accordance with the invention, the process is carried out through sequential combined application in three steps:
= Oxidative thermal treatment (reaction) = Thermal treatment under inert atmosphere (stabilization) = Fractional distillation in vacuum (adjustment of softening point and depletion of volatile components).
Pitch thus obtained, in comparison with that produced by standard processes, i.e.
EP-A-0167046, gives yields of about 50%. It is a pitch usable in multiple applications and has improved properties in relation to health (carcinogenic components content) and environment (volatile components content).
DESCRIPTION OF THE DRAWINGS
For carrying out the process according to the invention, it was used, though in no binding or limitative fashion, the pilot plant which scheme is illustrated in annexed Figure 1, and in which the respective numerical references designate:
1. Reactor 2. Recirculation pumps 3. Reagent dosing system (air/oxygen) 4. Static mixer 5. Oxygen analyzer 6. Thermal treatment vessel 7. Distillation column for softening point adjustment.
BACKGROUND OF THE INVENTION
Pitches are mostly produced by distillation of coal tar. The tar, once dehydrated and after removal of a first light fraction of BTX (<5%), gives rise to the following fractions according to the different distillation cuts:
= Naphthalene oil fraction. Within a distillation range of less than 260 C
and with a naphthalene content greater than 50%, it represents approximately 20% of the parent tar and is used for the recovery of naphthalene of high commercial value as well as for the production of technical oils.
= Anthracene oil fraction. A complex mixture of polycyclic aromatic hydrocarbons within a distillation range of 260-400 C mainly formed by anthracene, phenanthrene, fluoranthene, pyrene and carbazole. It represents approximately 30% of the parent tar, and is a directly marketable product for the production of carbon black in strong competition with various petroleum residues. Also would be of commercial interest the conversion into pitch of the major portion of this fraction.
= Pitch. The largest product obtained from tar distillation. It is a black solid with a softening point of about 30-250 C, characterized by its content of substances insoluble in certain solvents such as toluene and quinoline. It is a complex mixture of polycyclic aromatic hydrocarbons with three or more condensed aromatic rings and represents approximately 50% of the parent tar. It is one of the raw materials employed in the manufacture of electrodes for aluminium and graphite industries.
Since the method for producing pitch consists only in the separation of oils until adjustment of the softening point of the pitch pre-existing in tar, its production can be regarded accordingly as a pure physical operation. Therefore, the quality of pitches obtained by prior art techniques is ruled by the quality of the tars present in the production process.
The characteristic fact that coal tar is a byproduct from coke batteries makes this raw material a highly inconsistent product, and this drawback is only compensable through the formulation of suitable tar blends. In any event, all types of tars and, consequently, pitches obtained thereby, have solid particles in suspension (primary and secondary QI, and carry-over), besides different types of metallic sludge identifiable by its ashes content. Both pollutants prejudice pitch quality and/or decrease its potential application in advanced carbon materials.
Anthracene oil is obtained along distillation of coal tar and is characterized by its distillation range, which is comprised from about 260 C until the corresponding temperature for adjusting the softening point of the pitch obtained as a final product (generally 400-410 C). Anthracene oil is mostly constituted by aromatic hydrocarbons of 2-4 benzene rings and the corresponding heterocyclics with 0, N and S, phenanthrene, anthracene, fluoranthene, carbazole and pyrene being the main components. High aromaticity of anthracene oil and the characteristic of being a distilled product and entirely distillable in its whole range, convert this product into a raw material of highly consistent quality, what suggests the possibility of more refined uses.
Many of the aromatic hydrocarbons present in anthracene oil and some heteroaromatic ones are transformed into anisotropic and graphitizable carbonaceous materials by means of slow thermal treatment up to 1000 C in a closed vessel duly pressurized for avoiding evaporation. Thermal treatment up to a lower temperature would halt transformation at an intermediate stage -the pitch- although with a low yield thereof.
The process consists of a dehydrogenating aromatic condensation which is generated by radical pathways. Said intermediate step for producing pitch still proceeds under excessively high temperatures and low conversion rates for proper application at industrial level. All this suggests the possibility of inducing aromatic condensation by means of catalytic reactions that promote generation of radicals, and their condensation and dehydrogenation at lower temperatures with a higher yield. Among the possible inductors for this type of reactions, the catalysts of Friedel-Craft (BF3/HF, AICI3) and sulfur are well known. For the quality of the final products or by reason of operation costs and residues/byproducts generated such catalysts are not advisable, thus proposing for this case, and constituting an objective of the present invention, the use of oxygen, air, low-oxygen air or mixtures thereof in the reactions.
The treatment with air of tars and pitches as well as composite materials, self syntherizable mesophase and fibers has been used actually for different purposes such as the increase of molecular weight and softening point of pitches and tars, the avoidance of swelling during carbonization in composite carbon/carbon materials and self-syntherizabie mesophase, and the thermal stabilization of fibers before carbonization.
Patent EP-A-4167046 discloses the production of a pitch with low content in solids by means of oxidation with air or oxygen of a distillation fraction selected from coal tar or a heavy oil derived thereof, while heated at preferred temperatures of 315-385 C, though the possibility of operating at a lower temperature (149 C) is mentioned, until obtaining a desired intermediate product. This intermediate product is then submitted to distillation by stripping with steam or an inert gas, although said distillation could be avoided by using higher temperatures in the oxidation phase. The result is an impregnating pitch especially useful in the manufacture of electrodes.
Patent US 4892642 discloses the production of pitches from coal tars in three steps : an oxidative thermal treatment by 350-400 C and 1-3 atm, a thermal treatment under inert atmosphere and a fractional distillation.
The possibility of introducing an intermediate thermal treatment in order to improve both the pitch quality (in rheological terms and fixed carbon) and final yielding is not regarded in said patent. The pressure conditions or the time required for the processing steps are also not mentioned in the patent.
DESCRIPTION OF THE INVENTION
The process according to the invention, in comparison with the prior art, starts with a wider range of raw materials, including petrochemical aromatic fractions.
Pitches obtained in accordance with the invention, when compared with those of the prior art, present a higher intrinsic quality and improved properties in relation to health (carcinogenesis) and environment.
The reaction of anthracene oil with the oxygen present in the air at temperatures lower than 4000 C and preferably higher than 350 C, produces a molecular condensation through mechanisms that, in view of the reactivity of the main components of anthracene oil, appear to be similar to those present when sulfur is used as catalyst.
There has been observed that parameters such as temperature, residence time, gas flow (air/oxygen) and charge and pressure of the reactor, have an effect on the reaction course by favoring or inhibiting the aromatic condensation reactions, which are critical for the formation of compatible molecular structures able to promote aromatic condensation reactions instead of polymerization and cross-linking reactions.
An additional thermal treatment under inert atmosphere enables to increase planarity of molecules and to stabilize the reaction product, in the sense of filtering possible side reactions, which further promotes its wettability, increases its graphitizability and generally improves the reaction yield.
Pitches produced according to the present invention exhibit a substantial reduction in carcinogenic components due to the limited presence thereof in anthracene oil and their reaction through the proposed conditions of operation. At the same time, the performance of fractional distillation in vacuum, together with the molecular weight distribution achieved by means of the selected conditions of operation, produce a pitch with a reduced volatility what means a substantial environmental benefit.
The reaction of anthracene oil with air generates only water as byproduct/effluent (slightly polluted with ammonia and equivalent in composition to the ammoniacal waters obtained during the tar distillation process) and a gaseous current that comprises low-oxygen air, CO and CO2. Since the pitch or carbonaceous material is free from solid particles and metallic sludge, the resulting product will not contain such stuff.
According to the selected conditions of reaction, the resulting pitch can generate cokes which when observed under optical microscopy with polarized light, can appear as 100% anisotropic or 100% isotropic, depending on the properties of the pitch receiving interest.
In view of the advantageous characteristics of the pitches obtained by the process of the invention, such pitches are suitable for applications belonging to the field of carbon precursors and in particular are useful in the manufacture of electrodes for aluminium industry, graphite electrodes and synthetic graphite in general, binders for refractory industry, waterproof materials and electrometallurgical paste.
Due to the low selectivity of the reaction, the unreacted anthracene oil may be directly put in commerce, in accordance with the usual applications of said raw material obtained by tar distillation. Additionally, the increase of anthracene/phenanthrene concentration, as a consequence of these being poorly reactive components, would 5 provoke that said fraction could promote the actual interest in the manufacture of anthracene paste.
During the process, three phenomenological situations derived from side reactions to avoid are generated:
1. Formation of cross-linked structures/gums.
2. Generation of solid particles.
3. Generation of high molecular weight structures.
The conditions for the process were determined with the purpose of avoiding the above-mentioned side reactions, while maximizing yield, economy and safety of the process. For that reason, the following parameters of operation were selected:
= Temperature: 250-400 C, preferably 350-400 C.
= Pressure: 5-10 bar g.
= Specific airflow (21% 02): 0.1-0.25 kg/kg of anthracene oil.
= Residence time during reaction: 2-10 seconds, preferably 6-10 seconds.
= Conversion in a single step: s40%. By means of successive transformation steps, net yields of 60% or more can be achieved.
= Thermal treatment under inert atmosphere: 340-400 C, 3-10 hours, 0-10 bar g, preferably 370-400 C, atmospheric pressure and 4-6 hours.
= Distillation up to softening point: According to the application. In the range of 85-250 C Mettler for conventional applications.
In accordance with the invention, the process is carried out through sequential combined application in three steps:
= Oxidative thermal treatment (reaction) = Thermal treatment under inert atmosphere (stabilization) = Fractional distillation in vacuum (adjustment of softening point and depletion of volatile components).
Pitch thus obtained, in comparison with that produced by standard processes, i.e.
EP-A-0167046, gives yields of about 50%. It is a pitch usable in multiple applications and has improved properties in relation to health (carcinogenic components content) and environment (volatile components content).
DESCRIPTION OF THE DRAWINGS
For carrying out the process according to the invention, it was used, though in no binding or limitative fashion, the pilot plant which scheme is illustrated in annexed Figure 1, and in which the respective numerical references designate:
1. Reactor 2. Recirculation pumps 3. Reagent dosing system (air/oxygen) 4. Static mixer 5. Oxygen analyzer 6. Thermal treatment vessel 7. Distillation column for softening point adjustment.
8. Pressure regulator 9. Temperature regulators 10. Heating systems 11. Venting 12. Anthracene oil inlet 13. Purge 14. Recirculation of unreacted anthracene oil 15. Pitch outlet EXAMPLES
The following examples, given without limitative character, relate to embodiments of the invention.
As preferable raw material it is used anthracene oil arising from coal tar distillation with the following average characteristics (non-limitative aspect):
Raw material: Anthracene oil Origin Distillation of high temperature tar Distillation range (BS144) > 260 C
Density (ASTM D1298 > 1.120 /cm3 (20 C) Ashes (ASTM D482) < 0.02%
Toluene insolubles (BS144) <0.1%
C/H atomic ratio (ASTM D5291) > 1.30 According to the advantageous characteristics of the invention, different carbochemical fractions can be used by means of widening or narrowing the proposed distillation range, with no inconvenient for the quality of the product. The sole substantial variation to be obtained will be that derived from a higher or lower yield in the process.
Where non-carbochemical oils or components with a high content of heteroatoms, and/or components with high content of naphthenic structures and lateral chains are used, the reaction must be conducted under vigilance in order to avoid the formation of gums and cross-linked structures. It is recommendable to maximize the temperature and reduce the conversion to a single step.
Example 1 In the above-described pilot plant was processed an anthracene oil sample under the following conditions:
= Temperature: 300 C
= Residence time: 6 seconds = Specific airflow: 60 NI/h air per kg of oil = Pressure: 5 bar g Thermal treatment: 4000 C, 5 hours, 10 bar g = Distillation: Adjustment to softening point 90 C Mettler.
There was obtained a pitch with the following characteristics, in comparison with a standard impregnating pitch, and the net yield in pitch was 55%:
Parameter Units Example 1 Standard pitch Softening point ASTM D3104) C, Mettler 90 90 Flash point ASTM D92) C, COC 274 250-270 Toluene insolubles (ISO 6376) % 29.5 15.0 Quinoline insolubles ASTM D2318) % 1.0 0.8 Beta-resin % 28.5 14.2 Fixed carbon CRDG-B10 %, Sers 44.7 40.1 Filtration rate g, 80 min 43.3 (6 min 15-20 Ashes ASTM D2415) % <0.01 0.1 It is observable the substantial increase in the rheological properties, measured through filtration rate and increments in beta-resin and fixed carbon, of the resulting pitch.
Example 2 In the above-described pilot plant was processed an anthracene oil sample under the following conditions:
= Temperature: 3501 C
= Residence time: 4 seconds Specific airflow: 60 NI/h air per kg of anthracene oil = Pressure: 5 bar g = Thermal treatment: 400 C, 5 hours, 10 bar g = Distillation: Adjustment to softening point 90 C Mettler.
There was obtained a pitch with the following characteristics, in comparison with a standard impregnating pitch, and the net yield in pitch was 38%:
Parameter Units Exam le 2 Standard pitch Softening point (ASTM D3104) C, Mettler 90 90 Flash point (ASTM D92) C, COC 276 250-270 Toluene insolubles (ISO 6376) % 25.3 15.0 Quinoline insolubles (ASTM D2318) % 0.4 0.8 Beta-resin % 24.9 14.2 Fixed carbon CRDG-B10 %, Sers 43.1 40.1 Filtration rate g, 80 min 59 (6 min 15-20 Ashes (A TM D2415) % <0.01 0.1 It is observable that the control of the conversion and a higher reaction temperature (in regard to Example 1) provide a product with improved filtration rate and lower generation of quinoline insolubles, as a consequence of a lower generation of cross-linked structures, which are high molecular weight compounds, and since the process is carried out in less time, a lower generation of solids.
Example 3 In the above-described pilot plant was processed an anthracene oil sample under the following conditions:
= Temperature: 350 C
= Residence time: 4 seconds Specific airflow: 60 NI/h air per kg of anthracene oil = Pressure: 5 bar g = Thermal treatment: 400 C, 5 hours, 10 bar g = Distillation: Adjustment to softening point 110 C, Mettler.
There was obtained a pitch with the following characteristics, in comparison with a standard impregnating pitch, and the net yield in pitch was 35%:
Parameter Units Example 3 Standard pitch Softening point (ASTM D3104) C, Mettler 110 110 Volatiles (ASTM D2569) % a 360 C 0.0 0.3 Toluene insolubles (ISO 6376) % 29.2 29.0 Quinoline insolubles (ASTM D2318) % 1.3 10.0 Beta-resin % 27.9 19.0 Fixed carbon CRDG-B10 %, Sers 49.0 54.0 Wettability (CRDG SERS) C, Goutte 137 134 Ashes (ASTM D2415) % <0.01 0.1 B a P equiv. /k , EPA 18 28 In this example the resulting pitch would be suitable for its application as a binder pitch for electrodes in aluminium industry. When a greater ratio of quinoline insolubles is required, it is possible to prepare blends with a carbochemical pitch with high insolubles content, in which case there would be obtained a pitch with improved beta-resin and fixed carbon (normalized to the insolubles level) parameters.
From the above-mentioned properties can be deducted the potential advantages of the process for generating carbon precursors with less content in carcinogen compounds (B[a]P equiv.) and lower environmental impact (absence of volatile components at 360 C).
Example 4 In the above-described pilot plant was processed an anthracene oil sample under the following conditions:
= Temperature: 350 C
= Residence time: 4 seconds = Specific airflow: 60 NI/h air per kg of anthracene oil Pressure: 5 bar g = Thermal treatment: None = Distillation: Adjustment to softening point 90 C Mettler.
There was obtained a pitch with the below characteristics, in comparison with a standard impregnating pitch, and the net yield in pitch was 35%. In the following table are also enclosed, with a further comparative purpose, the results for the sample of Example 2 as reference data showing efficacy of the intermediate thermal treatment recommended by the invention.
Parameter Units Example 2 Standard Example 4 itch Softening point (ASTM D3104) C, Mettler 90 90 90 Flash point (ASTM D92) C, COC 276 250-270 272 Toluene insolubles (ISO 6376) % 25.3 15.0 23.8 Quinoline insolubles (ASTM D2318) % 0.4 0.8 0.5 Beta-resin % 24.9 14.2 23.3 Fixed carbon CRDG-B10 %, Sers 43.1 40.1 42.0 Filtration rate g, 80 min 59 (6 min) 15-20 67 (55 min Ashes (ASTM D2415) % <0.01 0.1 <0.01 In this case can be observed how the performance of a stabilizing thermal treatment improves filtration rate (rheological properties). At the same time, there is verified the influence over beta-resin, fixed carbon and global yield of the thermal 5 treatment.
The following examples, given without limitative character, relate to embodiments of the invention.
As preferable raw material it is used anthracene oil arising from coal tar distillation with the following average characteristics (non-limitative aspect):
Raw material: Anthracene oil Origin Distillation of high temperature tar Distillation range (BS144) > 260 C
Density (ASTM D1298 > 1.120 /cm3 (20 C) Ashes (ASTM D482) < 0.02%
Toluene insolubles (BS144) <0.1%
C/H atomic ratio (ASTM D5291) > 1.30 According to the advantageous characteristics of the invention, different carbochemical fractions can be used by means of widening or narrowing the proposed distillation range, with no inconvenient for the quality of the product. The sole substantial variation to be obtained will be that derived from a higher or lower yield in the process.
Where non-carbochemical oils or components with a high content of heteroatoms, and/or components with high content of naphthenic structures and lateral chains are used, the reaction must be conducted under vigilance in order to avoid the formation of gums and cross-linked structures. It is recommendable to maximize the temperature and reduce the conversion to a single step.
Example 1 In the above-described pilot plant was processed an anthracene oil sample under the following conditions:
= Temperature: 300 C
= Residence time: 6 seconds = Specific airflow: 60 NI/h air per kg of oil = Pressure: 5 bar g Thermal treatment: 4000 C, 5 hours, 10 bar g = Distillation: Adjustment to softening point 90 C Mettler.
There was obtained a pitch with the following characteristics, in comparison with a standard impregnating pitch, and the net yield in pitch was 55%:
Parameter Units Example 1 Standard pitch Softening point ASTM D3104) C, Mettler 90 90 Flash point ASTM D92) C, COC 274 250-270 Toluene insolubles (ISO 6376) % 29.5 15.0 Quinoline insolubles ASTM D2318) % 1.0 0.8 Beta-resin % 28.5 14.2 Fixed carbon CRDG-B10 %, Sers 44.7 40.1 Filtration rate g, 80 min 43.3 (6 min 15-20 Ashes ASTM D2415) % <0.01 0.1 It is observable the substantial increase in the rheological properties, measured through filtration rate and increments in beta-resin and fixed carbon, of the resulting pitch.
Example 2 In the above-described pilot plant was processed an anthracene oil sample under the following conditions:
= Temperature: 3501 C
= Residence time: 4 seconds Specific airflow: 60 NI/h air per kg of anthracene oil = Pressure: 5 bar g = Thermal treatment: 400 C, 5 hours, 10 bar g = Distillation: Adjustment to softening point 90 C Mettler.
There was obtained a pitch with the following characteristics, in comparison with a standard impregnating pitch, and the net yield in pitch was 38%:
Parameter Units Exam le 2 Standard pitch Softening point (ASTM D3104) C, Mettler 90 90 Flash point (ASTM D92) C, COC 276 250-270 Toluene insolubles (ISO 6376) % 25.3 15.0 Quinoline insolubles (ASTM D2318) % 0.4 0.8 Beta-resin % 24.9 14.2 Fixed carbon CRDG-B10 %, Sers 43.1 40.1 Filtration rate g, 80 min 59 (6 min 15-20 Ashes (A TM D2415) % <0.01 0.1 It is observable that the control of the conversion and a higher reaction temperature (in regard to Example 1) provide a product with improved filtration rate and lower generation of quinoline insolubles, as a consequence of a lower generation of cross-linked structures, which are high molecular weight compounds, and since the process is carried out in less time, a lower generation of solids.
Example 3 In the above-described pilot plant was processed an anthracene oil sample under the following conditions:
= Temperature: 350 C
= Residence time: 4 seconds Specific airflow: 60 NI/h air per kg of anthracene oil = Pressure: 5 bar g = Thermal treatment: 400 C, 5 hours, 10 bar g = Distillation: Adjustment to softening point 110 C, Mettler.
There was obtained a pitch with the following characteristics, in comparison with a standard impregnating pitch, and the net yield in pitch was 35%:
Parameter Units Example 3 Standard pitch Softening point (ASTM D3104) C, Mettler 110 110 Volatiles (ASTM D2569) % a 360 C 0.0 0.3 Toluene insolubles (ISO 6376) % 29.2 29.0 Quinoline insolubles (ASTM D2318) % 1.3 10.0 Beta-resin % 27.9 19.0 Fixed carbon CRDG-B10 %, Sers 49.0 54.0 Wettability (CRDG SERS) C, Goutte 137 134 Ashes (ASTM D2415) % <0.01 0.1 B a P equiv. /k , EPA 18 28 In this example the resulting pitch would be suitable for its application as a binder pitch for electrodes in aluminium industry. When a greater ratio of quinoline insolubles is required, it is possible to prepare blends with a carbochemical pitch with high insolubles content, in which case there would be obtained a pitch with improved beta-resin and fixed carbon (normalized to the insolubles level) parameters.
From the above-mentioned properties can be deducted the potential advantages of the process for generating carbon precursors with less content in carcinogen compounds (B[a]P equiv.) and lower environmental impact (absence of volatile components at 360 C).
Example 4 In the above-described pilot plant was processed an anthracene oil sample under the following conditions:
= Temperature: 350 C
= Residence time: 4 seconds = Specific airflow: 60 NI/h air per kg of anthracene oil Pressure: 5 bar g = Thermal treatment: None = Distillation: Adjustment to softening point 90 C Mettler.
There was obtained a pitch with the below characteristics, in comparison with a standard impregnating pitch, and the net yield in pitch was 35%. In the following table are also enclosed, with a further comparative purpose, the results for the sample of Example 2 as reference data showing efficacy of the intermediate thermal treatment recommended by the invention.
Parameter Units Example 2 Standard Example 4 itch Softening point (ASTM D3104) C, Mettler 90 90 90 Flash point (ASTM D92) C, COC 276 250-270 272 Toluene insolubles (ISO 6376) % 25.3 15.0 23.8 Quinoline insolubles (ASTM D2318) % 0.4 0.8 0.5 Beta-resin % 24.9 14.2 23.3 Fixed carbon CRDG-B10 %, Sers 43.1 40.1 42.0 Filtration rate g, 80 min 59 (6 min) 15-20 67 (55 min Ashes (ASTM D2415) % <0.01 0.1 <0.01 In this case can be observed how the performance of a stabilizing thermal treatment improves filtration rate (rheological properties). At the same time, there is verified the influence over beta-resin, fixed carbon and global yield of the thermal 5 treatment.
Claims (5)
1. A process for producing pitches from coal tars and distillates thereof carried out in three steps: oxidative thermal treatment, thermal treatment under inert atmosphere, and fractional distillation, characterized in that the oxidative thermal treatment step is carried out at a temperature of less than 400°C, a pressure of less than 10 bar g and a residence time in the range of 2 to 10 seconds, using as reagent air, oxygen, low-oxygen air, or mixtures thereof.
2. The process of claim 1, characterized in that as a byproduct there is obtained anthracene oil which exhibits an increased concentration of anthracene/phenanthrene.
3. The process of claim 1, characterized in that the temperature of the oxidative thermal treatment step ranges between 350 and 400°C.
4. The process of claim 1, characterized in that the pressure of the oxidative thermal treatment step ranges between 5 and 10 bar g.
5. The process of claim 1, characterized in that the residence time of the oxidative thermal treatment step ranges between 6 and 10 seconds.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ESP200400421 | 2004-02-20 | ||
| ES200400421A ES2238931B1 (en) | 2004-02-20 | 2004-02-20 | PROCEDURE FOR OBTAINING BREAS FROM ALQUITRANES AND ITS DISTILLATES FROM THE HULLA RENTAL, THROUGH OXIDATIVE THERMAL TREATMENT. |
| PCT/ES2005/000079 WO2005079136A2 (en) | 2004-02-20 | 2005-02-17 | Method for the production of brea from tar and the distillates thereof arising from coal tar by oxidative thermal treatment |
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| CA2556482A1 CA2556482A1 (en) | 2005-09-01 |
| CA2556482C true CA2556482C (en) | 2012-11-27 |
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| CA2556482A Active CA2556482C (en) | 2004-02-20 | 2005-02-17 | Process for producing pitches from coal, tars and distillates thereof by oxidative thermal treatment |
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| Country | Link |
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| EP (1) | EP1739153B1 (en) |
| JP (1) | JP2007525578A (en) |
| KR (1) | KR20070044800A (en) |
| CN (1) | CN1957061A (en) |
| AT (1) | ATE523579T1 (en) |
| BR (1) | BRPI0507215B1 (en) |
| CA (1) | CA2556482C (en) |
| DK (1) | DK1739153T3 (en) |
| ES (2) | ES2238931B1 (en) |
| PL (1) | PL1739153T3 (en) |
| WO (1) | WO2005079136A2 (en) |
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| BRPI0800466B1 (en) * | 2008-03-05 | 2016-05-17 | Saint Gobain Cerâmicas & Plásticos Ltda | process of developing an ecological bonding system for a refractory mass |
| US8747651B2 (en) * | 2008-05-22 | 2014-06-10 | Graftech International Holdings Inc. | High coking value pitch |
| RU2477744C1 (en) * | 2011-11-29 | 2013-03-20 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Башкирский государственный университет" | Method for obtaining oil pitches |
| JP6076147B2 (en) * | 2013-03-11 | 2017-02-08 | 株式会社クレハ | Manufacturing method of high softening point pitch |
| KR102207835B1 (en) * | 2013-12-23 | 2021-01-26 | 재단법인 포항산업과학연구원 | Method for preparing pitch for carbon material using coal tar distillate and pitch for carbon material prepared by the same |
| CN108003910B (en) * | 2016-10-27 | 2020-06-19 | 宝武炭材料科技有限公司 | Preparation method of high-softening-point environment-friendly asphalt, asphalt and application |
| CN107446606B (en) * | 2017-08-30 | 2024-01-23 | 西北大学 | Process and device for producing modified asphalt, aliphatic hydrocarbon and aromatic hydrocarbon from coal tar |
| KR102202219B1 (en) * | 2018-12-13 | 2021-01-12 | 재단법인 한국탄소융합기술원 | Method for densifying carbon block |
| US11248172B2 (en) | 2019-07-23 | 2022-02-15 | Koppers Delaware, Inc. | Heat treatment process and system for increased pitch yields |
| CN111518583B (en) * | 2020-04-20 | 2021-03-05 | 华中科技大学 | Solid waste pyrolysis liquid phase product fused salt gradient treatment impurity removal and quality improvement device |
| RU2744579C1 (en) * | 2020-06-01 | 2021-03-11 | Общество с ограниченной ответственностью "Объединенная Компания РУСАЛ Инженерно-технологический центр" | Method for obtaining binding pitch |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4146048A (en) * | 1977-05-02 | 1979-03-27 | Prefco Productions, Inc. | Fire damper and method of fabrication |
| GB2115437B (en) * | 1982-02-15 | 1985-10-02 | Nippon Oil Co Ltd | Pitch for carbon fibers |
| US4664774A (en) * | 1984-07-06 | 1987-05-12 | Allied Corporation | Low solids content, coal tar based impregnating pitch |
| US4892642A (en) * | 1987-11-27 | 1990-01-09 | Conoco Inc. | Process for the production of mesophase |
-
2004
- 2004-02-20 ES ES200400421A patent/ES2238931B1/en not_active Expired - Fee Related
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- 2005-02-17 BR BRPI0507215-8A patent/BRPI0507215B1/en active IP Right Grant
- 2005-02-17 PL PL05708091T patent/PL1739153T3/en unknown
- 2005-02-17 ES ES05708091T patent/ES2376938T3/en active Active
- 2005-02-17 KR KR1020067018337A patent/KR20070044800A/en not_active Application Discontinuation
- 2005-02-17 DK DK05708091.3T patent/DK1739153T3/en active
- 2005-02-17 CN CNA2005800117917A patent/CN1957061A/en active Pending
- 2005-02-17 WO PCT/ES2005/000079 patent/WO2005079136A2/en active Application Filing
- 2005-02-17 AT AT05708091T patent/ATE523579T1/en active
- 2005-02-17 JP JP2006553601A patent/JP2007525578A/en active Pending
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| Publication number | Publication date |
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| BRPI0507215B1 (en) | 2015-05-26 |
| DK1739153T3 (en) | 2012-01-09 |
| CA2556482A1 (en) | 2005-09-01 |
| WO2005079136A2 (en) | 2005-09-01 |
| JP2007525578A (en) | 2007-09-06 |
| BRPI0507215A (en) | 2007-06-19 |
| ES2238931B1 (en) | 2007-06-16 |
| WO2005079136A3 (en) | 2005-12-29 |
| ATE523579T1 (en) | 2011-09-15 |
| PL1739153T3 (en) | 2012-03-30 |
| ES2238931A1 (en) | 2005-09-01 |
| EP1739153A2 (en) | 2007-01-03 |
| KR20070044800A (en) | 2007-04-30 |
| CN1957061A (en) | 2007-05-02 |
| ES2376938T3 (en) | 2012-03-21 |
| EP1739153B1 (en) | 2011-09-07 |
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