CA1044167A - Preparation of petroleum pitch - Google Patents
Preparation of petroleum pitchInfo
- Publication number
- CA1044167A CA1044167A CA221,757A CA221757A CA1044167A CA 1044167 A CA1044167 A CA 1044167A CA 221757 A CA221757 A CA 221757A CA 1044167 A CA1044167 A CA 1044167A
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- Prior art keywords
- range
- fraction
- pressure
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- temperature
- Prior art date
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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
- C10C3/00—Working-up pitch, asphalt, bitumen
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Civil Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Structural Engineering (AREA)
- Materials Engineering (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Working-Up Tar And Pitch (AREA)
- Carbon And Carbon Compounds (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
PREPARATION OF PETROLEUM PITCH
Abstract of the Disclosure A process having a particular sequence of steps, each under specified conditions, for preparing a petroleum pitch binder suitable for electrodes used in smelting aluminum is disclosed.
In the essential steps of the invention a decant oil petroleum fraction is heat treated under pressure, the treated material is flashed to a lower pressure, and finally the material is oxy-activated under elevated temperature conditions to form a petroleum pitch having the desired properties.
Abstract of the Disclosure A process having a particular sequence of steps, each under specified conditions, for preparing a petroleum pitch binder suitable for electrodes used in smelting aluminum is disclosed.
In the essential steps of the invention a decant oil petroleum fraction is heat treated under pressure, the treated material is flashed to a lower pressure, and finally the material is oxy-activated under elevated temperature conditions to form a petroleum pitch having the desired properties.
Description
67' : :
This invention relates to the preparation of a petroleum pitch, and more particularly to a process for the conversion of a heavy clarified bottoms fraction of a catalytic gas oil cracking operation to a petroleum pitch acceptable to the aluminum industry as an electrode binder.
Numerous processes have been described in the literature for the preparation of petroleum pitches ~hich have been proposed as substitutes for coal tar pitch ~ut, despite the increasing c~st and shortage of coal tar pi~ch, much of the aluminum smelting industry has made little or no use of these previously proposed petroleum pitches as ~.
; -., a binder for the electrodes used in aluminum smelting pots.
Failure of petroleum pitch to achieve recognition as an acceptable binder appears to be particularly incongrusus when the material to be bound by the binder in electrodes for ~ aluminum smelting is another petroleum product, petroleum ;! coke~ Basic to the problem of substituting petroleum pitch for coal tar pitch as an electrode binder are the indefinite I and variable natures of the chemical c~mpositions or ;i 20 constitutions of both materials, and more particularly of the materials from which they are derived. As a consequence, l the tests;used to assess the suitabiIity of materials as binders il for electrodes are largely empirical and a final determination 1~, ~ . . .
of the suitability of a material as a binder can only be made by trial in a full scale operating aluminum potline. -- -Iowever, despite the empirical nature of much of the assessment of petroleum pitch as a binder for electrodes, certain essential or highly desirable properties of such binders are known and, to the extent that they can ~04L4~L167 be determined and compared, it :is necessary or advantageous to optimize them. Thus the softening point of a pitch can readily be measured and varied by appropriate variations in the steps used in preparation of the pitch. Softening point of a petrolaum pitch thus can be optimized to satisfy the particular temperature requirements for pitch that is appropriately fluid at the temperature of mixing with the coke and any other ~; materiaI to be bound thereby, and is solid at the ; temperatures at which the electrode~; formed therewith must subsequently be manipulated. Throughout this specification and ensuing claims, the softening point referred to is thak ;;
determined by the ASTM D36 (Ring and Ball) Method. Another more empirical assessment made on binder pitch is the so~
called "beta resin" content, or content of material ~ , ~ 15 insoluble in benzene but soluble in quinoline, as determined . , .
by successive extractions of pitch sampl~s with these solvent materia1s. "Beta resins" are believed to be desirable ingredients in electrode binder pi~ches, hence it is desirable to optimize the proportion of these materials in pitches when preparing the latter as electrode binders However, determination of the proportion generally is a t~me consuming operation involving prolonged solvent extractions, hence beta resin content generally is not a suitable parameter for purposes of process control, particularly for continuous processes. Likewise another ; empirical assessment i5 the coking value, which is an indication of the proportion of the pitch which will remain in the electrode as carbon after the electrode is baked.
~ However coking value determinations, done in the ; 11 : .
~ conventional manner for all carbonaceous materials, are .
` '' :
6~
also time consuming and hence they are not suitable for process control.
; In the prior art the processes used in efforts to prepare acceptable electrode binder pitch from the heavy clarified bottoms fraction of a catalytic gas oil ; cracking operation, commonly known as decant oil, have involved (1) heat treatment to induce cracking and ot'ner reactions which improved the properties of the products or use as electrode binder, and (2) ox.ida~ion by blowing heated 10 decant oil with gas containing free oxygen, again to induce reactions which improved the properties of the products for use as electrode binder. A combination of the thermal treatment followed by the oxidation process has also been suggested but the conditions heretofore prescribed for this -~ -sequence do not appear to have provided a product acceptable to the aluminum smelting industry as an electrode binder.
It has now been found that, with a preferred sequence of thermal and other treatment steps under specified conditions hereinafter set out, the third of which steps involves an activation with free oxygen, most conveniently , as àir ~oxyactivation), it is possible to prepare, from a full range decant oil having a boiling rang~ at atmospheric ~`i pressure at least 95% of which is above 450F (232C), ~ , , an electrode binder pitch which meets the requirements of the aluminum smelting industry. The invention thus consists in a proceqs for the preparation of a petroleum pit~h binder ; for the manùfacture of carbon electrodes, comprising (1) ¦ ~ubjecting a full range decant oil petroleum fraction, obtaine~
as the clarified bottoms fraction of a catalytic ga oil cracking operation and having a boiling range at atmospheric ~ -~, : :.
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~!134~67 pressure at least 95% of which is above 450F (232~), to a severe heat treatment by rapidly raising the temperature of the fraction to the range from 775 to 975F (413 to 524C) :-under a pressure in the range from 15 to 30 atmospheres and maintaining the temperature in said range for a period of from 3 to 300 minutes, (2) flashing the heat ~reated fraction at a lower pressure in the range from less than atmospheric to 4 atmospheres to separate volatilized ma~erial from a ~.
heat treated liquid fraction having a resultant ~o~tening point in the range from 150 to ~ F (65 to ~21C) and (3) .
subjecting the said liquid fraction to an oxy-activated condensation by maintaining it at a temperature in the range ;from 400 to 500F (204 to 260C) under a pressure in the range from atmospheric to 4 atmospheres, simultaneously with . ~
air being introduced into said fraction, preferably in a ~ :
proportion of at least 50 liters of air per hour per kilogram : .
of fraction, for a period of from one to 24 hours until said liquid fraction has a softening point in the range from 175 ;~
to 275F (79 to 135C).
It must be noted that the final step of the ! process of this invention, involving oxy-activated candensation, does more than merely raise the softening point of the product ~ to a desired value. For example it is possible to heat treat ::~ a ~irst sample of decant oil then vacuum flash distill the ~ 25 heat treated material to leave a residual first product having ."~ , - , , l he~same softening point as a second product made from a ; ~ : second sample of the same decant oil that is heat treated to the . ~
:; same extent as the first sample, then flashed at any :-convenient pressure to leave an intermediate residue having a ; :
.: 30 much lower softening point which is then raised by oxy~
activated condensation, as is done in the present invention, to form a second final product l _ 4 _.
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having the same softening point as the first product. However, although the two products have the same softeniny point, they have numerous other properties that are widely disparate, and the first product is not suitable as an electrode binder pitch for aluminum smelting, lacking for example a suitable proportion of "beta resin" content.
Throughout this specification and ensuing claims, .
any percentages expres~ed are percentages by weight unless .~ , otherwise specifically indicated.
It was previously indicated herein that the compositions of decant oils vary over a wide range. A~ readily -l determined by gradient elution chromatography, i.e. by the i adsorption of samples on a chromatographic column followed 1 : .
by elution of discrete fractions by selected solvents, components of decant oil include saturates (normal-, '.1 , iso-, and cyclo-paraffins), aromatics (alkyl benzenes, i ~ benzocyclo-paraffins, and polynuclear aromatics~includinq ! alkyl- and cycloalkyl substituted ones), and polars (primarily 1 heterocyclic nitrogen or oxygen containing aromatics); sulfur `l 20 compounds in the compositions are mostly included with the ) aromatics in such determinations, which are based on .: ,1 l modificatLons of the ASTM D2007 procedure. The desirable beta `~j resins in electrode binder pitch are known to be highly aromatic ! -in charactar, hence the aromatics content of decant oils ~ `
can be espected to contribute greatly to the formation of ;;~
beta resln in the preparation of electrode pitch from decant oil~ However the saturates content of decant oils has no~
been expected ko contribute signiEicantly to the formation of useful components of highly aromatlc electrode binder l - 5 -'l . .. .
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pitch. For this reason it has been the frequent practice, in trying to prepare acceptable electrode binder pitches from decant oils, to extract the bulk of the saturates from the oils and to prepare pitch from extracted decant oils which, by virtue of the removal of satuxates therefrom, have a much higher proportion of aromatics in their composition.
It has also been stated in the art that, when treating a decant oil with oxygen at elevated temperatures to make an electrode binder pitch, it is essential that the decant oil be an extracted material having the bulk of the ~aturates .
removed by the extraction. Obviously the additional extraction step increases the cost of producing electrode binder pitch from decant oil and reduces the yield of pitch potentially obtainable from the decant oil by removal of material that could otherwise beneficially appear in the pitch. Thus .1 it is completely unexpected that a full range (unex~racted) decant oil can be converted into an acceptable electrode binder pitch by a method which includes treating such decant oil with oxygen at elevated temperature.
As previously indicated herein, the present invention requires a specific sequence of three essential ~ ~
steps viz: (l) heating a ful1 range decant oil to a ~ -temperature in the range 775 to 975F (413 to 524C~ under LS to 30 atmospheres pressure for a restricted period of from -1: , ! 25 3 to 300 minute~, (2) flashing the hot oil at a lower pressure ;Z in the range from atmospheric to four atmospheres to remove a resulting portion of vaporized material, and t3) subjecting ~'j the re idual liq~lid fraction to an oxy-activated condensation by maintaining it at a temperature in the range from 400 to 500F (204 to 260C) under a pressure in the range from ;
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atmospheric to 4 atmospheres while simultaneously introducing air into the liquid fraction for a period of from one to 24 hours until it has a softening point in the range from 175 to 275F
(79 to 135C).
The first step in the process of the invention must be carried out under pressure in order to ensure that the material being heated remains predominantly in the liquid phase. The temperature achieved must be above sub~itantially 775F ~413~), as substantially no significant reaction occurs be~ow this value. In the upper part of the :1 , operative temperature range there may develop a tendency for some of the decant oil to crack to lower molecular we~ght products, and more energy is required to achieve this part of the operative range; it is preferred th~refore to operate in the range from 850 to 950F (454 to 510C) most preferably in the range 875 to 925F (468 to 496Ocj. The duration of time ~ -;3 for which the oil is maintained in the range above 775F (413C) must be in the range 3 to 300 minutes, with the longer times in thi~ range being required for the lower ~emperatures o the . .
opera~ive range. For example, substantially 300 minutes may be -, an appropriate time for reaction at operative temperatures , `l below 800F (427C) and substantially 15 minutes may be appxopriate~time for reaction at substantially 900F (482C~
I If temperatures in the operative range are maintained longer -l 25~ than appropriate, the reaction proceeds so far that the softening point of the resulting intermediate product material becomes so high that there is no accomodation for the rise in softening poin~ that will occur during the subsequent oxy activated condeniation step. As obtained from catalytic ; - 7 -, ,.. ~ . -,~ ' , :.; .. ., . ., ;.. , ~ ~ -.. , , .: . . . . . .. . ..
~Q~67 yas oil cracking operations, full range decant oil fractions have substantially no benzene insoluble content (generally less than 1%). Duxing the first step of the process o~ this invention the proportion of benzene insoluble material increases as the reaction proceeds, and absence of an increase in this proportion indicates that xeaction has not proceeded, and that the temperature has been too low or the time of reaction ~oo short or both. Desirab]y the proportion ~- increases to more than 5~, preferably to more ~han 10%, but, as indicated above, the reaction should not be made to proceed so far, under the influence of time and temperature, that the softening point of the intermediate product exceeds a ., ; value which does not provide sufficient allowance for the ensuing increase of the softening point which occurs during the subsequent oxy-activated condensation step. The first step -can be carried out as either a batch or continuous flow operation. ~ -Continuous flow operation is preferred as, among other things, it is more efficient in time utilization, especially when short reaction times are involved; also it provides the easiest means to maintain agitation to ensure optimum extent -~
,-;l of the deRired reactions which occur at the elevated .1 - -.:
temperature. Furthermore~ continuous flow operations are preferably carried out under conditions of turbulent flow "~
rather than laminar flow, as the former minimizes coke ~;
formation and helps maintain in su pension any coke ~hat is formed, thus reducing coke deposition on reactor walls;
furthermore it ensures even more efficient mixing of the material and reduces the time and/or tempera~ure conditions ~;
~ which would otherwise be required to achieve a desired degree .: '~ ': ' '.: . . . . .:
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of reaction.
Inasmuch as the second step of the process of the invention (flashing to reduce the pressure under which the material is maintained) inherently vaporizes the more volatile part of the material as well as discharging ga~es ~-evolved during the first step of the process, the material will undergo a slight inc~ease in softening point during the second step. As softening points are measured only at atmospheric pressure, it is the softening pOiilt of the material after the second step that is significant and should be taken into consideration when assessing the allowance to be made for the increase of softening point which will occur during the third step. And while softening point of the final product is not the only criterion of its quality, it is lS a convenient parameter which can readily be measured and used , as a criterion of the state of other essential parameters.
1 Generally, to satisfy the requirements of the aluminum industry, the petroleum electrode pitch, product of the final step of the proces , must have a softening point in the range ; ;
from 175 to 275F t79 to l35c?. Desirably, at least substantially 25F (14C; of tne increase in the softening point, which occurs during the process of the invention, is permitted to occur in the third step thereof. Preferably the re idue from the second step has a so~tening point in the range~from 150 to 200F (66 to 9 C~ In the third and final step in the process of the invention the intermediate product rom the second step is subjected to an oxy-activation at temperatures in the range from 400 to 500F (204 to 260C), preferably under pressure up to 4 atmospheres, with air being 9 ~
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injected into the liquid intermediate product, prefer~bly in conjunction with mechanical agitation such as stirring, the agitation being an aid to better dispersion of air and consequent activation of the reactions which occur. Although the oxygen in the air used is known to be essential to the activation of the reactions which take place, analysis of the .. . .
gases vented from the final step of the process shows that only a relatively small proportion of the oxygen in the air fed to the process is consumed, hence it is clear that the reactions :. .
; lO taking place, although oxy-activated, are not all simple oxygen ~ consuming reaction,. They are believed to be primarily condensation ,~ : ,. . .
reactions in which higher molecular weight compounds are formed by condensation of two or more lower molecular weight compounds under the activation of o~ygen at the elevated temperature prevailing. The oxygen is believed ~o promote the condensation reactions by acting as a hydrogen scavenger, forming water as byproduct. When mechanical agitation is not used as an aid to l .. ,.. :.-., dispersing air in the material being ~rea~ed, higher proportions i;
of air can be used to improve the disp~rsion by creating greater turbulence during passage through the material, for example, 500 ; liters per hour per kilogram of material being treated. When ~;
`` mechanical agitation is used, lower proportions of air may be used, ! for example less than lO0 liters per hour per kilogram of material ~
'I being treated. A convenient range to use with or without agitation -~ ~ -; j .
is in the range from 250 to 350 liters/hrjkg. of material. Care must be taken however, to ensure that air is not dispersed into i . .~ .
oil at a temperature so high that uncontrolled or runaway exothermic oxidation reaction develops. For this reason the temper~-ture during the oxy-activation must be monitored and controlled ,.................................................................... .
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13~4~L67 within the specified range. The oxy-activation can be carried out as a batch or a con~inuous operation, care being taken in either case to ensure sufficient time for the oxy-activated reactions to occur in the chosen equipment at the desired temperature S selected from the specified range. The continuance of the oxy-activated condensation for a period of from one to 24 hours, preferably between threeandten hours, causes an increase in the softening point of the intermediate product, and pre~erably the condensation is continued until the softening point o the material has risen at least 25F (14C), but not beyond the desired final value in the range from 175 to 275F (79 to 135C).
The volatile products which separate during the last step of the process-can be disposed of in any convenient manner, there being sufficient fuel value in them to warrant combustion as fuel for example. The residual material, on cooling to ambient ~ room temperature, solidifies to a brittle petroleum pitch produc~.
`~ The invention can now be more readily described I by reference to the following examples which are given to i}lustrate the invention without limiting the scope thereof as defined in the ensuing claims.
.
` EXAMPLE 1 ~ ~
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To carry out the first step of the proces~ :
~^I of the invention for this example, a full range decant oil was fed continuously to a tubular reactor heated by immersion -~
~25 in a bed of sand fluidized with a steady stream of nitrogen and~with the bed maintained at a desired elevated temperature by electric reslstance heaters. A preheat section of the reactor sexved to raise the temperature of the decant oil ~ ~1 ~ ~, rapidly to a~out 900F (482C). The decant oil used had an initial boiling point of substantially 410F (210C) , . : - 1 1 - , . . , ,", , ' ~ ', : . ,; , . , , : , : ~ .: . ~ , and substantially 99~ boiled in the range up to 1100F (593C);
it contained less than 1~ benzene insoluble material. The oil was fed to the reactor at a rate of 1090 gm. per hour which provided a residence time in the tube at a temperature above about 900F (4~2C) of 11.6 minutes. Averaged temperature in the tube for this period was 940F (504C). Pressure in the reactor was maintained at about 300 psig (20 atmospheres).
On passing continuously from the reactor through a pres~ure reducing valve the heat-treated matexial flowed into and wa~
accumulated in a vacuum flash pot maintained at an absolute pressure of 150 mm. Hg. The accumulated material ~as drained periodically to storage at atmospheric pressure.
This liquid intermediate product, obtained in a yield of 56.3% by wei~3ht of the feed, was found to have a Softening lS Point of 164F ~73C), a Benzene Insoluble content of 12.7%, Quinoline Insoluble content of 0.9%, and a coking value of 40.5. An additional 31.2~ of the feed was recovered as ~. . ..
overhead oil condensed from the vapors evolved in the flash -, potj and the remaining 12.5~ of the feed was vented as ; -uncondensed gases from the flash pot. Four batches of the liquid l material were charged in turn to a stirred autoclave having ;
i a volume capacity of about five liters. It was equipped ll with feed and product removal lines, a~ impeller type ' stirrer, a sparger to distribute air into the bottom of he ~; 2S ket~le con~ents, and a vent line with a condenser for liquid ~;~
overhead products, a back pressure regulator to maintain air pre~sure in the kettle at a set value, and a wet test meter ~^ ;
to measure the volume of vented gas. Air was sparged into -each batch at a measured rate while the material was held at ~ ~-~'~ , .. .
.. . , , , . . - . . . .
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a temperature of 445 to 450F (229 to 232C) with the pressure maintained around 3 atmospheres absolute; the reac~ion conditions were maintained for 2.8 hour~ for tha first batch and 4.0 ; hours for the other three batches. Following the period of ; 5 air sparging at the indicated temperature which induced ; oxy~activated condensations in the batches, the material was drained from the autoclave and its softening point determined.
In the following Table 1 are listed the weight (in kilograms) of the four batches (a) to (d), the flow rate of air to 10 each batch (in liters/hour/kg. of ba~ch), the weight (in grams) , of condensed liquid recovered from the vented gases, and the Softening Point (in F and C) of the batch product.
, .i ., Batch Weight Air Rate Overhead S.P.
~'I (kg)(l/hr/k~) Conds.(gm) ~F & (C)) ~ :
~i (a) 3967 347 0 206 (97) ~b) 4254 295 27 199 (93) (c) 407~ 293 13 203 ~94)
This invention relates to the preparation of a petroleum pitch, and more particularly to a process for the conversion of a heavy clarified bottoms fraction of a catalytic gas oil cracking operation to a petroleum pitch acceptable to the aluminum industry as an electrode binder.
Numerous processes have been described in the literature for the preparation of petroleum pitches ~hich have been proposed as substitutes for coal tar pitch ~ut, despite the increasing c~st and shortage of coal tar pi~ch, much of the aluminum smelting industry has made little or no use of these previously proposed petroleum pitches as ~.
; -., a binder for the electrodes used in aluminum smelting pots.
Failure of petroleum pitch to achieve recognition as an acceptable binder appears to be particularly incongrusus when the material to be bound by the binder in electrodes for ~ aluminum smelting is another petroleum product, petroleum ;! coke~ Basic to the problem of substituting petroleum pitch for coal tar pitch as an electrode binder are the indefinite I and variable natures of the chemical c~mpositions or ;i 20 constitutions of both materials, and more particularly of the materials from which they are derived. As a consequence, l the tests;used to assess the suitabiIity of materials as binders il for electrodes are largely empirical and a final determination 1~, ~ . . .
of the suitability of a material as a binder can only be made by trial in a full scale operating aluminum potline. -- -Iowever, despite the empirical nature of much of the assessment of petroleum pitch as a binder for electrodes, certain essential or highly desirable properties of such binders are known and, to the extent that they can ~04L4~L167 be determined and compared, it :is necessary or advantageous to optimize them. Thus the softening point of a pitch can readily be measured and varied by appropriate variations in the steps used in preparation of the pitch. Softening point of a petrolaum pitch thus can be optimized to satisfy the particular temperature requirements for pitch that is appropriately fluid at the temperature of mixing with the coke and any other ~; materiaI to be bound thereby, and is solid at the ; temperatures at which the electrode~; formed therewith must subsequently be manipulated. Throughout this specification and ensuing claims, the softening point referred to is thak ;;
determined by the ASTM D36 (Ring and Ball) Method. Another more empirical assessment made on binder pitch is the so~
called "beta resin" content, or content of material ~ , ~ 15 insoluble in benzene but soluble in quinoline, as determined . , .
by successive extractions of pitch sampl~s with these solvent materia1s. "Beta resins" are believed to be desirable ingredients in electrode binder pi~ches, hence it is desirable to optimize the proportion of these materials in pitches when preparing the latter as electrode binders However, determination of the proportion generally is a t~me consuming operation involving prolonged solvent extractions, hence beta resin content generally is not a suitable parameter for purposes of process control, particularly for continuous processes. Likewise another ; empirical assessment i5 the coking value, which is an indication of the proportion of the pitch which will remain in the electrode as carbon after the electrode is baked.
~ However coking value determinations, done in the ; 11 : .
~ conventional manner for all carbonaceous materials, are .
` '' :
6~
also time consuming and hence they are not suitable for process control.
; In the prior art the processes used in efforts to prepare acceptable electrode binder pitch from the heavy clarified bottoms fraction of a catalytic gas oil ; cracking operation, commonly known as decant oil, have involved (1) heat treatment to induce cracking and ot'ner reactions which improved the properties of the products or use as electrode binder, and (2) ox.ida~ion by blowing heated 10 decant oil with gas containing free oxygen, again to induce reactions which improved the properties of the products for use as electrode binder. A combination of the thermal treatment followed by the oxidation process has also been suggested but the conditions heretofore prescribed for this -~ -sequence do not appear to have provided a product acceptable to the aluminum smelting industry as an electrode binder.
It has now been found that, with a preferred sequence of thermal and other treatment steps under specified conditions hereinafter set out, the third of which steps involves an activation with free oxygen, most conveniently , as àir ~oxyactivation), it is possible to prepare, from a full range decant oil having a boiling rang~ at atmospheric ~`i pressure at least 95% of which is above 450F (232C), ~ , , an electrode binder pitch which meets the requirements of the aluminum smelting industry. The invention thus consists in a proceqs for the preparation of a petroleum pit~h binder ; for the manùfacture of carbon electrodes, comprising (1) ¦ ~ubjecting a full range decant oil petroleum fraction, obtaine~
as the clarified bottoms fraction of a catalytic ga oil cracking operation and having a boiling range at atmospheric ~ -~, : :.
. . , ', ., :
, ,- . : , , . :
, ,~
~!134~67 pressure at least 95% of which is above 450F (232~), to a severe heat treatment by rapidly raising the temperature of the fraction to the range from 775 to 975F (413 to 524C) :-under a pressure in the range from 15 to 30 atmospheres and maintaining the temperature in said range for a period of from 3 to 300 minutes, (2) flashing the heat ~reated fraction at a lower pressure in the range from less than atmospheric to 4 atmospheres to separate volatilized ma~erial from a ~.
heat treated liquid fraction having a resultant ~o~tening point in the range from 150 to ~ F (65 to ~21C) and (3) .
subjecting the said liquid fraction to an oxy-activated condensation by maintaining it at a temperature in the range ;from 400 to 500F (204 to 260C) under a pressure in the range from atmospheric to 4 atmospheres, simultaneously with . ~
air being introduced into said fraction, preferably in a ~ :
proportion of at least 50 liters of air per hour per kilogram : .
of fraction, for a period of from one to 24 hours until said liquid fraction has a softening point in the range from 175 ;~
to 275F (79 to 135C).
It must be noted that the final step of the ! process of this invention, involving oxy-activated candensation, does more than merely raise the softening point of the product ~ to a desired value. For example it is possible to heat treat ::~ a ~irst sample of decant oil then vacuum flash distill the ~ 25 heat treated material to leave a residual first product having ."~ , - , , l he~same softening point as a second product made from a ; ~ : second sample of the same decant oil that is heat treated to the . ~
:; same extent as the first sample, then flashed at any :-convenient pressure to leave an intermediate residue having a ; :
.: 30 much lower softening point which is then raised by oxy~
activated condensation, as is done in the present invention, to form a second final product l _ 4 _.
:~ ,'' ' ~ ' :
. ~,~,; :. ;
,-, , ~
: , : :, . , , . . : ' , , - , , :
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having the same softening point as the first product. However, although the two products have the same softeniny point, they have numerous other properties that are widely disparate, and the first product is not suitable as an electrode binder pitch for aluminum smelting, lacking for example a suitable proportion of "beta resin" content.
Throughout this specification and ensuing claims, .
any percentages expres~ed are percentages by weight unless .~ , otherwise specifically indicated.
It was previously indicated herein that the compositions of decant oils vary over a wide range. A~ readily -l determined by gradient elution chromatography, i.e. by the i adsorption of samples on a chromatographic column followed 1 : .
by elution of discrete fractions by selected solvents, components of decant oil include saturates (normal-, '.1 , iso-, and cyclo-paraffins), aromatics (alkyl benzenes, i ~ benzocyclo-paraffins, and polynuclear aromatics~includinq ! alkyl- and cycloalkyl substituted ones), and polars (primarily 1 heterocyclic nitrogen or oxygen containing aromatics); sulfur `l 20 compounds in the compositions are mostly included with the ) aromatics in such determinations, which are based on .: ,1 l modificatLons of the ASTM D2007 procedure. The desirable beta `~j resins in electrode binder pitch are known to be highly aromatic ! -in charactar, hence the aromatics content of decant oils ~ `
can be espected to contribute greatly to the formation of ;;~
beta resln in the preparation of electrode pitch from decant oil~ However the saturates content of decant oils has no~
been expected ko contribute signiEicantly to the formation of useful components of highly aromatlc electrode binder l - 5 -'l . .. .
. ` '. , , . :
.~
' .-` `
,~ -,- , : , .. ..
~:: . . . - ,; ~. , - . , .. : , . .. . . . .
6~
pitch. For this reason it has been the frequent practice, in trying to prepare acceptable electrode binder pitches from decant oils, to extract the bulk of the saturates from the oils and to prepare pitch from extracted decant oils which, by virtue of the removal of satuxates therefrom, have a much higher proportion of aromatics in their composition.
It has also been stated in the art that, when treating a decant oil with oxygen at elevated temperatures to make an electrode binder pitch, it is essential that the decant oil be an extracted material having the bulk of the ~aturates .
removed by the extraction. Obviously the additional extraction step increases the cost of producing electrode binder pitch from decant oil and reduces the yield of pitch potentially obtainable from the decant oil by removal of material that could otherwise beneficially appear in the pitch. Thus .1 it is completely unexpected that a full range (unex~racted) decant oil can be converted into an acceptable electrode binder pitch by a method which includes treating such decant oil with oxygen at elevated temperature.
As previously indicated herein, the present invention requires a specific sequence of three essential ~ ~
steps viz: (l) heating a ful1 range decant oil to a ~ -temperature in the range 775 to 975F (413 to 524C~ under LS to 30 atmospheres pressure for a restricted period of from -1: , ! 25 3 to 300 minute~, (2) flashing the hot oil at a lower pressure ;Z in the range from atmospheric to four atmospheres to remove a resulting portion of vaporized material, and t3) subjecting ~'j the re idual liq~lid fraction to an oxy-activated condensation by maintaining it at a temperature in the range from 400 to 500F (204 to 260C) under a pressure in the range from ;
. ~ .
;., ": "~
..
~ .. . ..
,:
,.. - . , , ,. ; . ~, . . . . .
,.. . .: ~ , ~4~
atmospheric to 4 atmospheres while simultaneously introducing air into the liquid fraction for a period of from one to 24 hours until it has a softening point in the range from 175 to 275F
(79 to 135C).
The first step in the process of the invention must be carried out under pressure in order to ensure that the material being heated remains predominantly in the liquid phase. The temperature achieved must be above sub~itantially 775F ~413~), as substantially no significant reaction occurs be~ow this value. In the upper part of the :1 , operative temperature range there may develop a tendency for some of the decant oil to crack to lower molecular we~ght products, and more energy is required to achieve this part of the operative range; it is preferred th~refore to operate in the range from 850 to 950F (454 to 510C) most preferably in the range 875 to 925F (468 to 496Ocj. The duration of time ~ -;3 for which the oil is maintained in the range above 775F (413C) must be in the range 3 to 300 minutes, with the longer times in thi~ range being required for the lower ~emperatures o the . .
opera~ive range. For example, substantially 300 minutes may be -, an appropriate time for reaction at operative temperatures , `l below 800F (427C) and substantially 15 minutes may be appxopriate~time for reaction at substantially 900F (482C~
I If temperatures in the operative range are maintained longer -l 25~ than appropriate, the reaction proceeds so far that the softening point of the resulting intermediate product material becomes so high that there is no accomodation for the rise in softening poin~ that will occur during the subsequent oxy activated condeniation step. As obtained from catalytic ; - 7 -, ,.. ~ . -,~ ' , :.; .. ., . ., ;.. , ~ ~ -.. , , .: . . . . . .. . ..
~Q~67 yas oil cracking operations, full range decant oil fractions have substantially no benzene insoluble content (generally less than 1%). Duxing the first step of the process o~ this invention the proportion of benzene insoluble material increases as the reaction proceeds, and absence of an increase in this proportion indicates that xeaction has not proceeded, and that the temperature has been too low or the time of reaction ~oo short or both. Desirab]y the proportion ~- increases to more than 5~, preferably to more ~han 10%, but, as indicated above, the reaction should not be made to proceed so far, under the influence of time and temperature, that the softening point of the intermediate product exceeds a ., ; value which does not provide sufficient allowance for the ensuing increase of the softening point which occurs during the subsequent oxy-activated condensation step. The first step -can be carried out as either a batch or continuous flow operation. ~ -Continuous flow operation is preferred as, among other things, it is more efficient in time utilization, especially when short reaction times are involved; also it provides the easiest means to maintain agitation to ensure optimum extent -~
,-;l of the deRired reactions which occur at the elevated .1 - -.:
temperature. Furthermore~ continuous flow operations are preferably carried out under conditions of turbulent flow "~
rather than laminar flow, as the former minimizes coke ~;
formation and helps maintain in su pension any coke ~hat is formed, thus reducing coke deposition on reactor walls;
furthermore it ensures even more efficient mixing of the material and reduces the time and/or tempera~ure conditions ~;
~ which would otherwise be required to achieve a desired degree .: '~ ': ' '.: . . . . .:
~j . .
.. . .. .
: , .: ,' ' i . '- ' ., ,.,. ~, .
L67 ::
of reaction.
Inasmuch as the second step of the process of the invention (flashing to reduce the pressure under which the material is maintained) inherently vaporizes the more volatile part of the material as well as discharging ga~es ~-evolved during the first step of the process, the material will undergo a slight inc~ease in softening point during the second step. As softening points are measured only at atmospheric pressure, it is the softening pOiilt of the material after the second step that is significant and should be taken into consideration when assessing the allowance to be made for the increase of softening point which will occur during the third step. And while softening point of the final product is not the only criterion of its quality, it is lS a convenient parameter which can readily be measured and used , as a criterion of the state of other essential parameters.
1 Generally, to satisfy the requirements of the aluminum industry, the petroleum electrode pitch, product of the final step of the proces , must have a softening point in the range ; ;
from 175 to 275F t79 to l35c?. Desirably, at least substantially 25F (14C; of tne increase in the softening point, which occurs during the process of the invention, is permitted to occur in the third step thereof. Preferably the re idue from the second step has a so~tening point in the range~from 150 to 200F (66 to 9 C~ In the third and final step in the process of the invention the intermediate product rom the second step is subjected to an oxy-activation at temperatures in the range from 400 to 500F (204 to 260C), preferably under pressure up to 4 atmospheres, with air being 9 ~
'i : ~ ~ .
'.'i: ~ ''.~.
~' . ..
,.~ i .,: . - . :. .
~44~6~
injected into the liquid intermediate product, prefer~bly in conjunction with mechanical agitation such as stirring, the agitation being an aid to better dispersion of air and consequent activation of the reactions which occur. Although the oxygen in the air used is known to be essential to the activation of the reactions which take place, analysis of the .. . .
gases vented from the final step of the process shows that only a relatively small proportion of the oxygen in the air fed to the process is consumed, hence it is clear that the reactions :. .
; lO taking place, although oxy-activated, are not all simple oxygen ~ consuming reaction,. They are believed to be primarily condensation ,~ : ,. . .
reactions in which higher molecular weight compounds are formed by condensation of two or more lower molecular weight compounds under the activation of o~ygen at the elevated temperature prevailing. The oxygen is believed ~o promote the condensation reactions by acting as a hydrogen scavenger, forming water as byproduct. When mechanical agitation is not used as an aid to l .. ,.. :.-., dispersing air in the material being ~rea~ed, higher proportions i;
of air can be used to improve the disp~rsion by creating greater turbulence during passage through the material, for example, 500 ; liters per hour per kilogram of material being treated. When ~;
`` mechanical agitation is used, lower proportions of air may be used, ! for example less than lO0 liters per hour per kilogram of material ~
'I being treated. A convenient range to use with or without agitation -~ ~ -; j .
is in the range from 250 to 350 liters/hrjkg. of material. Care must be taken however, to ensure that air is not dispersed into i . .~ .
oil at a temperature so high that uncontrolled or runaway exothermic oxidation reaction develops. For this reason the temper~-ture during the oxy-activation must be monitored and controlled ,.................................................................... .
,: -- 1 0 ~
:. . .
;! ... :: .
~: ' '': '' ' :, ~ , .. -:
;' ::,.
' ':
.'' , :
' . . ' ,: ' . :. ` ' : , ' .
13~4~L67 within the specified range. The oxy-activation can be carried out as a batch or a con~inuous operation, care being taken in either case to ensure sufficient time for the oxy-activated reactions to occur in the chosen equipment at the desired temperature S selected from the specified range. The continuance of the oxy-activated condensation for a period of from one to 24 hours, preferably between threeandten hours, causes an increase in the softening point of the intermediate product, and pre~erably the condensation is continued until the softening point o the material has risen at least 25F (14C), but not beyond the desired final value in the range from 175 to 275F (79 to 135C).
The volatile products which separate during the last step of the process-can be disposed of in any convenient manner, there being sufficient fuel value in them to warrant combustion as fuel for example. The residual material, on cooling to ambient ~ room temperature, solidifies to a brittle petroleum pitch produc~.
`~ The invention can now be more readily described I by reference to the following examples which are given to i}lustrate the invention without limiting the scope thereof as defined in the ensuing claims.
.
` EXAMPLE 1 ~ ~
:, , . :
To carry out the first step of the proces~ :
~^I of the invention for this example, a full range decant oil was fed continuously to a tubular reactor heated by immersion -~
~25 in a bed of sand fluidized with a steady stream of nitrogen and~with the bed maintained at a desired elevated temperature by electric reslstance heaters. A preheat section of the reactor sexved to raise the temperature of the decant oil ~ ~1 ~ ~, rapidly to a~out 900F (482C). The decant oil used had an initial boiling point of substantially 410F (210C) , . : - 1 1 - , . . , ,", , ' ~ ', : . ,; , . , , : , : ~ .: . ~ , and substantially 99~ boiled in the range up to 1100F (593C);
it contained less than 1~ benzene insoluble material. The oil was fed to the reactor at a rate of 1090 gm. per hour which provided a residence time in the tube at a temperature above about 900F (4~2C) of 11.6 minutes. Averaged temperature in the tube for this period was 940F (504C). Pressure in the reactor was maintained at about 300 psig (20 atmospheres).
On passing continuously from the reactor through a pres~ure reducing valve the heat-treated matexial flowed into and wa~
accumulated in a vacuum flash pot maintained at an absolute pressure of 150 mm. Hg. The accumulated material ~as drained periodically to storage at atmospheric pressure.
This liquid intermediate product, obtained in a yield of 56.3% by wei~3ht of the feed, was found to have a Softening lS Point of 164F ~73C), a Benzene Insoluble content of 12.7%, Quinoline Insoluble content of 0.9%, and a coking value of 40.5. An additional 31.2~ of the feed was recovered as ~. . ..
overhead oil condensed from the vapors evolved in the flash -, potj and the remaining 12.5~ of the feed was vented as ; -uncondensed gases from the flash pot. Four batches of the liquid l material were charged in turn to a stirred autoclave having ;
i a volume capacity of about five liters. It was equipped ll with feed and product removal lines, a~ impeller type ' stirrer, a sparger to distribute air into the bottom of he ~; 2S ket~le con~ents, and a vent line with a condenser for liquid ~;~
overhead products, a back pressure regulator to maintain air pre~sure in the kettle at a set value, and a wet test meter ~^ ;
to measure the volume of vented gas. Air was sparged into -each batch at a measured rate while the material was held at ~ ~-~'~ , .. .
.. . , , , . . - . . . .
, ,, ... ~ ., .,, . . . ,: , , ., , ,; .
,. ' .. ,. : . ~:,: . . . . . . . . . .. . . . . . . . .
a temperature of 445 to 450F (229 to 232C) with the pressure maintained around 3 atmospheres absolute; the reac~ion conditions were maintained for 2.8 hour~ for tha first batch and 4.0 ; hours for the other three batches. Following the period of ; 5 air sparging at the indicated temperature which induced ; oxy~activated condensations in the batches, the material was drained from the autoclave and its softening point determined.
In the following Table 1 are listed the weight (in kilograms) of the four batches (a) to (d), the flow rate of air to 10 each batch (in liters/hour/kg. of ba~ch), the weight (in grams) , of condensed liquid recovered from the vented gases, and the Softening Point (in F and C) of the batch product.
, .i ., Batch Weight Air Rate Overhead S.P.
~'I (kg)(l/hr/k~) Conds.(gm) ~F & (C)) ~ :
~i (a) 3967 347 0 206 (97) ~b) 4254 295 27 199 (93) (c) 407~ 293 13 203 ~94)
2~ (d~ 4351 268 22 200 (93) The four product batches were composited and additional measurements of properties of the composite material were -~
made with the following results: ~-Softening Point - 201F ~94C) Benzene I~soluble Material - 21.3 ;, ~ Quinoline Insoluble Material - 0.6%
~ Coking Value - 44.6 :, , ~ , , ; ~ `, ! : - 13 -, :~
~,;
. ' 1 :
,: : . . , : :... . .
4~67 The first step of the process in this example was likewise carried out in a similar tubular reactor to that previously described in Example 1. The decant oil used for the feed to the reactor had an initial boiling point of ~ :
substantially 406F (208C), a final boiling point of substantially 1067F (575C) and 95% of it boiled above 467F (242C). The oil was fed to the reactor at a rate of 1640 gmæ. per hour which pxovided a residence time for the feed in the tube at a temperature above about 900F
:l (482C~ of 13.5 minutes. Pressure in the reactor wa~ : ~
.' maintained at about 300 psig (20 atmospheres) and a~eraged : :
tempsrature in the tube was 930F (499C). On passing con inuously ;~ :.
from the reactor the heat-treated material flowed into, and .. ::
was ~ccumulated in, a vacuum flash pot which was maintained
made with the following results: ~-Softening Point - 201F ~94C) Benzene I~soluble Material - 21.3 ;, ~ Quinoline Insoluble Material - 0.6%
~ Coking Value - 44.6 :, , ~ , , ; ~ `, ! : - 13 -, :~
~,;
. ' 1 :
,: : . . , : :... . .
4~67 The first step of the process in this example was likewise carried out in a similar tubular reactor to that previously described in Example 1. The decant oil used for the feed to the reactor had an initial boiling point of ~ :
substantially 406F (208C), a final boiling point of substantially 1067F (575C) and 95% of it boiled above 467F (242C). The oil was fed to the reactor at a rate of 1640 gmæ. per hour which pxovided a residence time for the feed in the tube at a temperature above about 900F
:l (482C~ of 13.5 minutes. Pressure in the reactor wa~ : ~
.' maintained at about 300 psig (20 atmospheres) and a~eraged : :
tempsrature in the tube was 930F (499C). On passing con inuously ;~ :.
from the reactor the heat-treated material flowed into, and .. ::
was ~ccumulated in, a vacuum flash pot which was maintained
3 at an absolute pressure of 100 mmO Hg. and from which l ..
~ accumulated liquid was periodically drained to atmospheric , 1 , , .
I pressure~ The accumulated liquid intermediate product was obtained in a yield of 57.6% by weight of the feed, with 36.0%
2~ by weight of the feed being recovered as oil condensed from :
1 the vapors èvolved in the flash pot and the remaining 6.4% of ;.
`l the ~eed being vented as uncondensed gases. The intermediate ~r ,~ product was found to have a Softening Point of 173F (78C), 3 a Bqnzene Insolubles content of 9.5%, Quinoline Insolubles : 25 content of 0.4~, and a Coking Value of 42.6. As in Example 1, four:batches of the intermediate product were charged in turn to the same stirred autoclave and each batch was agitated and maintained:at 450F (232C~ for a specific period under ., I . . .
~ :pressure of 3 to 3.S atmospheres absolute. Following the :, - 14 ~
,~ ., '~. ,., :
,. , ,;:
. . . :, .
., : ... ..
. ~ : . : . . , . , . :
period of oxy-activated reactions, the material of each batch was drained from the autoclave and its softening point determined.
The petroleum pitch products obtained from the batches then were composited and additional properties of the composite 5 were determined. In the following Table 2 are listed, for the four batches ~a) to (d) respectively, the rate of Rparging air into the batch in liters/hour/kg. of batch, the duration of the sparging operation in hours, the weight in grams o~ the condensed liquid recovered from the vented gases;
10 and the Softening Point in F and C of the batch pitch product.
', .
; TABLE 2 Batch ~ir Rate TimeOverhead S.P.
(lJhr/kg) (hours) Cond9- (gm? (F & (C~) , (a) 294.0 10.3274 248 (120) (b) 334.3 8.33 245 (118) (c) ~75.7 9.021 ~ 246 (119) `
(d) 285.7 10.06 250 ~121) 2~ From a total eed of 16.22 kg. of feed in the four batches l a composite petroleum pitch product weighing 15.86 kg. was ;l obtained, 2 yield of 97.8~. The composite pitch had a Softening Point of 242~F (117C), a Benzene Insolubles content of 26.8%, Quinoline Insolubles of 0.3%, and a Coking Value o~ 49.7.
Numero~s propertie~ of electrodes, prepared from each of the-petroleum pitch products of the foregoing two examples, were determined ~or both Soderbe~g and pre-baked type electrodes. For properties such as Binder Content, `
Paste Elongation, Paste Thermal Stability, Green Apparent - 15 ~-, .
1~4~ 7 Density, Baked Apparent Density, Volume Change on Baking, Air Permeability, Electric Resistivity, Compressive Strength, Bending Strength, Pseudo-tens.ile Strength~ Young's Modulus, Thermal Conductivity, Coefficient of Thermal Expansion, Air Oxidat.ion Rate, Anode Consumption, and others, the value~
found were held by an aluminum smelter to be acceptable for use of the pitches in aluminum potlines for the ~melting of alumina.
~umerous modifications can be made in the specific expedients described without departing from the invention ~: di~closed, the scope of which is defined in the following claims.
:, -: ', ,~, .
~, "
.: ,,.
~. .
', ~, ,, ; i ' ~ ',, '' .
"'1 ~' '.,' : -'.'"' ' "' ; , "' " ':
';. ,, ':
~, , ' ' ' . ':
: ~ ' " , I ~ 16 -. ~ .
' .
, ' ''' ~ .' ,:,
~ accumulated liquid was periodically drained to atmospheric , 1 , , .
I pressure~ The accumulated liquid intermediate product was obtained in a yield of 57.6% by weight of the feed, with 36.0%
2~ by weight of the feed being recovered as oil condensed from :
1 the vapors èvolved in the flash pot and the remaining 6.4% of ;.
`l the ~eed being vented as uncondensed gases. The intermediate ~r ,~ product was found to have a Softening Point of 173F (78C), 3 a Bqnzene Insolubles content of 9.5%, Quinoline Insolubles : 25 content of 0.4~, and a Coking Value of 42.6. As in Example 1, four:batches of the intermediate product were charged in turn to the same stirred autoclave and each batch was agitated and maintained:at 450F (232C~ for a specific period under ., I . . .
~ :pressure of 3 to 3.S atmospheres absolute. Following the :, - 14 ~
,~ ., '~. ,., :
,. , ,;:
. . . :, .
., : ... ..
. ~ : . : . . , . , . :
period of oxy-activated reactions, the material of each batch was drained from the autoclave and its softening point determined.
The petroleum pitch products obtained from the batches then were composited and additional properties of the composite 5 were determined. In the following Table 2 are listed, for the four batches ~a) to (d) respectively, the rate of Rparging air into the batch in liters/hour/kg. of batch, the duration of the sparging operation in hours, the weight in grams o~ the condensed liquid recovered from the vented gases;
10 and the Softening Point in F and C of the batch pitch product.
', .
; TABLE 2 Batch ~ir Rate TimeOverhead S.P.
(lJhr/kg) (hours) Cond9- (gm? (F & (C~) , (a) 294.0 10.3274 248 (120) (b) 334.3 8.33 245 (118) (c) ~75.7 9.021 ~ 246 (119) `
(d) 285.7 10.06 250 ~121) 2~ From a total eed of 16.22 kg. of feed in the four batches l a composite petroleum pitch product weighing 15.86 kg. was ;l obtained, 2 yield of 97.8~. The composite pitch had a Softening Point of 242~F (117C), a Benzene Insolubles content of 26.8%, Quinoline Insolubles of 0.3%, and a Coking Value o~ 49.7.
Numero~s propertie~ of electrodes, prepared from each of the-petroleum pitch products of the foregoing two examples, were determined ~or both Soderbe~g and pre-baked type electrodes. For properties such as Binder Content, `
Paste Elongation, Paste Thermal Stability, Green Apparent - 15 ~-, .
1~4~ 7 Density, Baked Apparent Density, Volume Change on Baking, Air Permeability, Electric Resistivity, Compressive Strength, Bending Strength, Pseudo-tens.ile Strength~ Young's Modulus, Thermal Conductivity, Coefficient of Thermal Expansion, Air Oxidat.ion Rate, Anode Consumption, and others, the value~
found were held by an aluminum smelter to be acceptable for use of the pitches in aluminum potlines for the ~melting of alumina.
~umerous modifications can be made in the specific expedients described without departing from the invention ~: di~closed, the scope of which is defined in the following claims.
:, -: ', ,~, .
~, "
.: ,,.
~. .
', ~, ,, ; i ' ~ ',, '' .
"'1 ~' '.,' : -'.'"' ' "' ; , "' " ':
';. ,, ':
~, , ' ' ' . ':
: ~ ' " , I ~ 16 -. ~ .
' .
, ' ''' ~ .' ,:,
Claims (4)
1. A process for the preparation of a petroleum pitch binder for the manufacture of carbon electrodes, consisting essentially of (1) subjecting a full range decant oil petroleum fraction, obtained as the clarified bottoms fraction of a catalytic gas oil cracking operation and having a boiling range at atmospheric pressure at least 95% of which is above 450°F (232°C), to a severe heat treatment in the absence of any free oxygen containing gas by rapidly raising the temperature of the fraction to the range from 775 to 975°F (413 to 524°C) under a pressure in the range from 15 to 30 atmospheres and maintaining the temperature in said range for a period of from 3 to 300 minutes until the proportion of benzene material in the fraction has risen to at least 5% by weight, (2) flashing the heat treated fraction at a lower pressure in the range from less than atmospheric to 4 atmospheres to separate volatilized material from a heat treated liquid fraction having a resultant softening point in the range from 150 to 250°F
(66 to 121°C) and (3) subjecting the said liquid fraction to an oxy-activated condensation by maintaining it at a temperature in the range from 400 to 500°F (204 to 260°C) under a pressure in the range from atmospheric to 4 atmospheres, simultaneously with air being introduced into said fraction, for a period of from three to ten hours with air flow between substantially 100 to 500 liters per hour per kilogram of material being treated until said liquid fraction has a softening point in the range from 175 to 275°F (79 to 135°C).
(66 to 121°C) and (3) subjecting the said liquid fraction to an oxy-activated condensation by maintaining it at a temperature in the range from 400 to 500°F (204 to 260°C) under a pressure in the range from atmospheric to 4 atmospheres, simultaneously with air being introduced into said fraction, for a period of from three to ten hours with air flow between substantially 100 to 500 liters per hour per kilogram of material being treated until said liquid fraction has a softening point in the range from 175 to 275°F (79 to 135°C).
2. A process as claimed in Claim 1, in which the decant oil is raised to and held at temperature in the range from 850 to 950°F (454 to 510°C) for a period less than substantially 15 minutes by passage of a continuous flow thereof through a heated tube reactor at substantially 20 atmospheres pressure, said period providing an increase to substantially 10% in the proportion of benzene insoluble material in the heated decant oil.
3. A process as claimed in Claim 2 in which the heated decant oil subsequently is vacuum flash distilled to remove the more volatile material and leave a residue having a softening point in the range from 150 to 200°F (66 to 93°C).
4. A process as claimed in Claim 3 in which the oxy-activated condensation is carried out under air pressure of substantially three atmospheres with mechanical agitation and for a period of from substantially three to ten hours with air flows between substantially 250 and substantially 350 liters per hour per kilogram of material being treated.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA221,757A CA1044167A (en) | 1975-03-06 | 1975-03-06 | Preparation of petroleum pitch |
| DE2608466A DE2608466C2 (en) | 1975-03-06 | 1976-03-01 | Process for the manufacture of a petroleum pitch binder for the manufacture of carbon electrodes |
| JP51021881A JPS5943513B2 (en) | 1975-03-06 | 1976-03-02 | Petroleum pitch manufacturing method |
| GB8827/76A GB1541674A (en) | 1975-03-06 | 1976-03-05 | Preparation of petroleum pitch |
| FR7606482A FR2303062A1 (en) | 1975-03-06 | 1976-03-08 | PREPARATION OF A BINDER FOR ELECTRODES BASED ON PETROLEUM BRAI |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA221,757A CA1044167A (en) | 1975-03-06 | 1975-03-06 | Preparation of petroleum pitch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1044167A true CA1044167A (en) | 1978-12-12 |
Family
ID=4102486
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA221,757A Expired CA1044167A (en) | 1975-03-06 | 1975-03-06 | Preparation of petroleum pitch |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS5943513B2 (en) |
| CA (1) | CA1044167A (en) |
| DE (1) | DE2608466C2 (en) |
| FR (1) | FR2303062A1 (en) |
| GB (1) | GB1541674A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4664774A (en) * | 1984-07-06 | 1987-05-12 | Allied Corporation | Low solids content, coal tar based impregnating pitch |
| JPS61103989A (en) * | 1984-10-29 | 1986-05-22 | Maruzen Sekiyu Kagaku Kk | Production of pitch for manufacture of carbon product |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2046081A (en) * | 1934-03-23 | 1936-06-30 | Standard Oil Co | Process for manufacturing asphaltic products |
| US2991241A (en) * | 1957-09-11 | 1961-07-04 | Sinclair Refining Co | Process for the production of pitch comprising heating and concurrently airblowing the bottoms of a distilled catalytically cracked gas oil |
| US3238116A (en) * | 1963-12-12 | 1966-03-01 | Exxon Research Engineering Co | Coke binder oil |
| CH478907A (en) * | 1966-05-18 | 1969-09-30 | Continental Oil Co | Process for making a petroleum-based pitch |
-
1975
- 1975-03-06 CA CA221,757A patent/CA1044167A/en not_active Expired
-
1976
- 1976-03-01 DE DE2608466A patent/DE2608466C2/en not_active Expired
- 1976-03-02 JP JP51021881A patent/JPS5943513B2/en not_active Expired
- 1976-03-05 GB GB8827/76A patent/GB1541674A/en not_active Expired
- 1976-03-08 FR FR7606482A patent/FR2303062A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS51111233A (en) | 1976-10-01 |
| GB1541674A (en) | 1979-03-07 |
| FR2303062A1 (en) | 1976-10-01 |
| DE2608466C2 (en) | 1986-05-22 |
| FR2303062B1 (en) | 1981-03-20 |
| JPS5943513B2 (en) | 1984-10-22 |
| DE2608466A1 (en) | 1976-09-16 |
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