CA1173773A - Process for modifying coal tar materials - Google Patents
Process for modifying coal tar materialsInfo
- Publication number
- CA1173773A CA1173773A CA000377822A CA377822A CA1173773A CA 1173773 A CA1173773 A CA 1173773A CA 000377822 A CA000377822 A CA 000377822A CA 377822 A CA377822 A CA 377822A CA 1173773 A CA1173773 A CA 1173773A
- Authority
- CA
- Canada
- Prior art keywords
- tar
- solvent
- coal
- pitch
- fraction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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
- C10C1/18—Working-up tar by extraction with selective solvents
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)
Abstract
PROCESS FOR MODIFYING COAL-TAR MATERIALS
ABSTRACT
The present invention relates to a process for de-creasing and modifying the quinoline-insoluble content (Q.I.) of coal-tar materials; and comprises extracting the coal-tar material with a solvent, where the solvent contains at least one of n-methyl-2-pyrrolidone and the wash oil fraction of coal-tar distillate. Pitches with a diminished Q.I. content, lower viscosity and lower average Q.I.
particle size, may be prepared from coal-tar materials which have been so treated.
ABSTRACT
The present invention relates to a process for de-creasing and modifying the quinoline-insoluble content (Q.I.) of coal-tar materials; and comprises extracting the coal-tar material with a solvent, where the solvent contains at least one of n-methyl-2-pyrrolidone and the wash oil fraction of coal-tar distillate. Pitches with a diminished Q.I. content, lower viscosity and lower average Q.I.
particle size, may be prepared from coal-tar materials which have been so treated.
Description
3~73 Field of the Invention The present invention relates to a method of modi-fying coal-tars. More particularly it relates to a method of decreasing and/or modifying the quinoline insoluble content therein.
Background of the Invention/Prior Art Coal-tar is usually obtained as a by-product of the distillation of coal in coke ovens, e.g. in the manu-facture of metallurgical coke. It comprises a mixture of a number of hydrocarbon compounds which can be separated by distillation of the tar. Pitch, which is the residue in the still following such a distillation is a viscuous material which softens and flows when heated. Pitches are conven-tionally classified according to their softening points and their solubility in various solvents eg. quinoline, benzene and dimethylformamide~ The latter characteristic is usually indicated by the proportion of the pitch which is insoluble in the solvent eg. the proportion of the pitch which is quinoline-insoluble (Q.I.) is a widely-used pitch character-istic.
Much of the Q.I. formation takes place at the hightemperature to which the tar is subjected during coke forma-tion, and stays in the pitch residue following distilla-tion. The presence of the Q.I. in the tar or pitch can be tolerated for a limited number of applications; however, in most of the uses, the presence of significant amounts of Q.I. is viewed as an undesirable characteristic of the mate-rial. The particulate nature of the Q.I. renders difficult virtually any process which requires the passage of the pitch through small orifices; eg. penetration of pitch is rendered difficult. Additionally, should the Q.I. have a high content of ash-forming impurities, the combustion rate of the carbon body produced by coking (or otherwise
Background of the Invention/Prior Art Coal-tar is usually obtained as a by-product of the distillation of coal in coke ovens, e.g. in the manu-facture of metallurgical coke. It comprises a mixture of a number of hydrocarbon compounds which can be separated by distillation of the tar. Pitch, which is the residue in the still following such a distillation is a viscuous material which softens and flows when heated. Pitches are conven-tionally classified according to their softening points and their solubility in various solvents eg. quinoline, benzene and dimethylformamide~ The latter characteristic is usually indicated by the proportion of the pitch which is insoluble in the solvent eg. the proportion of the pitch which is quinoline-insoluble (Q.I.) is a widely-used pitch character-istic.
Much of the Q.I. formation takes place at the hightemperature to which the tar is subjected during coke forma-tion, and stays in the pitch residue following distilla-tion. The presence of the Q.I. in the tar or pitch can be tolerated for a limited number of applications; however, in most of the uses, the presence of significant amounts of Q.I. is viewed as an undesirable characteristic of the mate-rial. The particulate nature of the Q.I. renders difficult virtually any process which requires the passage of the pitch through small orifices; eg. penetration of pitch is rendered difficult. Additionally, should the Q.I. have a high content of ash-forming impurities, the combustion rate of the carbon body produced by coking (or otherwise
- 2 -~ 73~73carbonizing~ the pitch will be significantly increased.
Accordingly, it is an object of this invention to provide a process for decreasing and modifying the quinoline-insoluble content in coal-tar material.
It is also an object of this invention to provide a process for obtaining pitch material with a diminished content of quinoline-insoluble materialO
Brief Description of the Invention In one aspect, the present invention relates to a process for decreasing and modifying the quinoline-insoluble content (Q.I.) of coal-tar material comprising: mixing the coal-tar material with a solvent which contains at least one of n-methyl-2-pyrrolidone and the fraction of a coal-tar distillate which boils between 100 and 350C, thereby to form a solvent-dissolved fraction and a solvent-undissolved fraction of the coal-tar material, separating the two fractions, where the Q~Io of the coal-tar material is concentrated in the latter fraction; and the solvent-dissolved fraction comprises coal-tar material with a decreased and modified Q.I. Preferably, the process comprises the additional step of recovering the solvent.
In another aspect, the present invention relates to the production of pitch material by the distillation of the aforesaid solvent-dissolved fraction where the pitch has a reduced and modified Q.I.
Brief Description of the Drawings : Figure 1 is a schematic flow diagram which illustrates the steps which an embodiment of this invention entails.
Figure 2 (Figures 2(a) and 2(b)) are scanning electron microscope photographs of the insoluble particulate matter in the tar and pitch respectively.
Accordingly, it is an object of this invention to provide a process for decreasing and modifying the quinoline-insoluble content in coal-tar material.
It is also an object of this invention to provide a process for obtaining pitch material with a diminished content of quinoline-insoluble materialO
Brief Description of the Invention In one aspect, the present invention relates to a process for decreasing and modifying the quinoline-insoluble content (Q.I.) of coal-tar material comprising: mixing the coal-tar material with a solvent which contains at least one of n-methyl-2-pyrrolidone and the fraction of a coal-tar distillate which boils between 100 and 350C, thereby to form a solvent-dissolved fraction and a solvent-undissolved fraction of the coal-tar material, separating the two fractions, where the Q~Io of the coal-tar material is concentrated in the latter fraction; and the solvent-dissolved fraction comprises coal-tar material with a decreased and modified Q.I. Preferably, the process comprises the additional step of recovering the solvent.
In another aspect, the present invention relates to the production of pitch material by the distillation of the aforesaid solvent-dissolved fraction where the pitch has a reduced and modified Q.I.
Brief Description of the Drawings : Figure 1 is a schematic flow diagram which illustrates the steps which an embodiment of this invention entails.
Figure 2 (Figures 2(a) and 2(b)) are scanning electron microscope photographs of the insoluble particulate matter in the tar and pitch respectively.
- 3 ~'7~7~3 Detailed Description of the Invention -Accordingly, the present invention relates to a process whereby the content of quinoline-insolubles (Q.I.) in coal-tar material can be decreased. The coal-tar materi-al which has been thus treated can be distilled in order to obtain a pitch having a diminished Q.I. Additionally, the Q.I. contained in the pitch so obtained will usually have a size distribution different from a conventionally obtained pitch having the same Q.I. This latter attribute of the present invention is referred to as the "modification" of the Q.I..The present invention additionally relates to a novel coal tar pitch material having a significantly reduced viscosity and a lower average particle size.
Broadly, the process of the present invention com-prises a solvent extraction of coal-tar material in order to separate the quinoline-soluble from the quinoline-insoluble components; where the solvent chosen for this procedure con~
tains at least one of n-methyl-2-pyrrolidone and the frac-tion of the coal-tar distillate which boils between 100 and 350C, preferably between 200 and 350C~ In the following, the latter solvent will be referred to as wash oil, a term which is widely used in the art. The mixing of coal-tar ma-terial with the solvent results in the formation of two fractions which can be subsequently separated, viz. the solvent-dissolved and that undissolved in the solvent, with most of the Q.I. being localized in the latter fraction, while the former fraction comprising the coal-tar material has a greatly reduced Q.I. These fractions may be separated by conventional techniques such as filtration, centrifuga-tion, decantation and the like. The solvent-dissolved frac-tion of the coal-tar material so treated can be distilled to separate the various fractions with different boiling points and obtain a pitch material with a significantly diminished 73~3 Q.I. The pitch material, thus produced has a number of characteristics and uses that are associated with a low Q.I., a substantially reduced viscosity, and a relatively low average size of particulate matter. The distillation, which serves to separate the higher boiling components from the pitch residue, also serves to separate the n-methyl-2-pyrrolidone from the higher boiling components with which it distils over. The n-methyl-2-pyrrolidone has a lower boil-ing point than the light boilers contained in the distillate and can be separated therefrom. The wash oil fraction of the distillate can be permitted to distil over with the n-methyl-2-pyrrolidone and can equivalently (individually, or in combination with the n-methyl-2-pyrrolidone) be used as a solvent in this solvent extraction process. This will permit some flexibility in the distillation procedure. The n-methyl-2-pyrrolidone and/or the wash oil fraction which will be contained in the distillate can then be recycled ~or use in the extraction of more coal-tar material.
The amount of solvent employed for this extraction will be partiall~ determined by the viscosity of the resul-tant coal-tar-solvent mixture required for the separation technique (and which is also dependent upon the temperature of this process) and by the amount required to dissolve sub-stantially all th2 quinoline soluble material. Typically, the proportion of the solvent in the mixture will usually range ~rom about 20 to 80% of the mixture, ie. the solvent:
tar ratio will be in the range 1:4 to 4:1.
Turning now to the single figure (Figure 1), we note that n~methyl-2-pyrrolidone which is introduced via line 01, can be mixed with recycled solvent which can addi-tionally contain some light boilers and is introduced to the mixing tank 10, via line 02 where it is mixed with the untreated tar which has been introduced to the tank via line ~.~73773 04, at a temperature high enough to facilitate its handling and further processing. The mixture then passes via ].ine 06 to the separation step 20 where the solvent-dissolved frac-tion and the fraction insoluble in the solvent are sep~rat-ed, possibly by differences in specific gravity or by filtration, as a result of which the former fraction leaves this step via line 08 and the latter fraction via line 07.
The former fraction which contains a tar with a depleted Q.I. can be distilled in the distillation step 30 from which the n-methyl 2-pyrrolidone and the light boilers come over as the earlier fr~ctions of the distillate and can be separated from each other, at separation step 40, if so desired or recycled via lines 13 and 15 for use as a solvent in the extraction of subsequent batches of coal-tar material. The pitch residue obtained from this distillation via line 09 will have a substantially reduced viscosity, a lower average particle size of insolubles, in addition to a reduced Q.I. content.
The advantages accruing to the user of this pro-cess are many, not the least of which is the extent of the Q.I. removal from the coal-tar which results from the use of this process. Some of the other advantageous features of this process stem from the solvent system used in this pro-cess viz. the n-methyl-2-pyrrolidone and/or the light boil-ing cut of the tar distillate; in particular, the ease with which the solvent can be used, recovered, reused; and the facility with which these operations can be integrated into a conventional pitch production process.
A surprising outcome of this process is the manner in which the viscosity of the pitch and the size distribu~
tion of the Q.I~ is affected. The size distribution of a pitch derived from an unextracted tar, or one extracted with a solvent different from that of the present invention, is " ~73773 often characterized by a greater degree of particulate agglomeration. The pitch material thus obtained is charac-terized by a viscosity lower than that of pitches obtained by the distillation of the untreated coal tar. This is particularly important where the particulate size of the pitch is important e.g. in applications such as the impregnation of prebaked electrodes.
The following examples will serve to illustrate the invention.
Example 1 This example illustrates how the Q.I. of a conven-tional coal tar material can be decreased by the present invention using the light boilers of coal tar distillation (wash oil) as the solvent.
A sample of coal-tar having a Q.I. of 6.5~, and representative of the output obtained from steel mills was mixed with wash oil in a tar to wash oil ratio of 3:2. The mixture was filtered using a Buchner funnel and No. 1 analytical filter paper with a moderate vacuum being applied to accelerate the process. The Q.I. of the treated tar was measured. The filtrate was then distilled under atmo-spheric pressure, and the Q.I. content of the pitch residue determined in accordance with ASTM D2318. The experimental : recults are summarized in Table 1 below. The above proce-dure was repeated with two other commercially available coal tar samples having Q.I values of 7.0 and 23.7% respective-ly. In each of the cases, the Q.I. in the treated tar was a small fraction of that in the original sample.
A possibly more remarkable outcome which was in-dicative of the degree to which the process resulted in theQ.I. removal was the low Q.I. content in the pitch residue as compared to the original tar. This is surprising because Q.I. is hormally concentrated in the pitch, partly due to a 3~7~3 large decrease in the volume, and partly due to some crack-ing which occurs during the distillation. Nonetheless, in all the cases the Q.I. in the pitch was a small fraction of that in the tar prior to filtration.
i The above procedure was repeated with the same three tar samples, but with a tar:solvent ratio of 104. The experimental results which are qualitatively substantially the same as the preceding set; are also summarized in Table 1 below.
Table 1 _.~,. . .
, ., ,Q.I. (%) 'Coal Tar.Tar: Solvent'Untreated~ QoI~ (%) 'Q.I.(%) Sample ' Ratio . Tar ' (Treated Tar) '(Pitch) 1 , 3:2 '6.5 . 0.02 , 0.3 2 J 3:2 '7.0 ' 0.5 . 1.0 1 3 ' 3:2 '23.7 0.7 ~.5 ` ' 1 , 1:4 '6.5 ' 0.5 . 0.5 ' 2 ' 104 .7.0 ' 0.03 ' O.S g i 3 i 1:4 j23.7 ~ 0 3 i 3 0 Exam21e 2 This example illustrates the use of n-methyl-2-pyrrolidone as the solvent in the extraction of the Q.I.
from the tar, Tar samples identical to those in example 1 were subjected to essentially the same procedure and tests as~
described above in the preceding Example. The results of these experimental runs which are summarized in Table 2 below follow essentially the same pattern as in the preced ing Example. The treated tar has a greatly reduced Q.I.
which is also manifested in the low Q.I. content of the pitch residue remaining after the distillation of the tar.
3~7i73 Table 2 , Q.I. (%) l ' Coal Tar'Tar: Solvent'Untreated' Q.I. (%) 'Q.I.(%).
Sample ' Ratio ' Tar . (Treated Tar) '(Pitch)' 1 : 3:2 . 5.0 0.1 0.7 ' 2 ' 3:2 ' 4.2 ' 0.1 . 3.4 . 3 , 3:2 '18.2 ' 0.3 . 4.5 ,_ ., .. ._ , . ., . . , ~
1 , 1:4 , 5.0 0~2 , 1.3 2 ' 1:4 , 4.2 ' 0.1 ' 1.8 i 3 i 1:4 j18.2 , 0-03 i 5.1 . . . .
Example 3 This example presents a qualitative comparison of particle sizes of insolubles in tar which has been extracted using a conventional solvent (in this case quinoline), and that which is residual in E~ after an extraction of the precursor tar according to the present invention.
Figure 2(a) is a scanning electron microscope (S.B.M.) photograph of residual tar Q.I. following an extraction using quinoline. Figure 2(b) is a S.E.M. photo-graph of the insolubles in a pitch prepared from an identical tar after extraction with n-methyl-2-pyrrolidone.
It will readily moved that typical particle sizes in the former photograph are greater than about 1 micron, with sizes of the agglomerated particles ranging up to about
Broadly, the process of the present invention com-prises a solvent extraction of coal-tar material in order to separate the quinoline-soluble from the quinoline-insoluble components; where the solvent chosen for this procedure con~
tains at least one of n-methyl-2-pyrrolidone and the frac-tion of the coal-tar distillate which boils between 100 and 350C, preferably between 200 and 350C~ In the following, the latter solvent will be referred to as wash oil, a term which is widely used in the art. The mixing of coal-tar ma-terial with the solvent results in the formation of two fractions which can be subsequently separated, viz. the solvent-dissolved and that undissolved in the solvent, with most of the Q.I. being localized in the latter fraction, while the former fraction comprising the coal-tar material has a greatly reduced Q.I. These fractions may be separated by conventional techniques such as filtration, centrifuga-tion, decantation and the like. The solvent-dissolved frac-tion of the coal-tar material so treated can be distilled to separate the various fractions with different boiling points and obtain a pitch material with a significantly diminished 73~3 Q.I. The pitch material, thus produced has a number of characteristics and uses that are associated with a low Q.I., a substantially reduced viscosity, and a relatively low average size of particulate matter. The distillation, which serves to separate the higher boiling components from the pitch residue, also serves to separate the n-methyl-2-pyrrolidone from the higher boiling components with which it distils over. The n-methyl-2-pyrrolidone has a lower boil-ing point than the light boilers contained in the distillate and can be separated therefrom. The wash oil fraction of the distillate can be permitted to distil over with the n-methyl-2-pyrrolidone and can equivalently (individually, or in combination with the n-methyl-2-pyrrolidone) be used as a solvent in this solvent extraction process. This will permit some flexibility in the distillation procedure. The n-methyl-2-pyrrolidone and/or the wash oil fraction which will be contained in the distillate can then be recycled ~or use in the extraction of more coal-tar material.
The amount of solvent employed for this extraction will be partiall~ determined by the viscosity of the resul-tant coal-tar-solvent mixture required for the separation technique (and which is also dependent upon the temperature of this process) and by the amount required to dissolve sub-stantially all th2 quinoline soluble material. Typically, the proportion of the solvent in the mixture will usually range ~rom about 20 to 80% of the mixture, ie. the solvent:
tar ratio will be in the range 1:4 to 4:1.
Turning now to the single figure (Figure 1), we note that n~methyl-2-pyrrolidone which is introduced via line 01, can be mixed with recycled solvent which can addi-tionally contain some light boilers and is introduced to the mixing tank 10, via line 02 where it is mixed with the untreated tar which has been introduced to the tank via line ~.~73773 04, at a temperature high enough to facilitate its handling and further processing. The mixture then passes via ].ine 06 to the separation step 20 where the solvent-dissolved frac-tion and the fraction insoluble in the solvent are sep~rat-ed, possibly by differences in specific gravity or by filtration, as a result of which the former fraction leaves this step via line 08 and the latter fraction via line 07.
The former fraction which contains a tar with a depleted Q.I. can be distilled in the distillation step 30 from which the n-methyl 2-pyrrolidone and the light boilers come over as the earlier fr~ctions of the distillate and can be separated from each other, at separation step 40, if so desired or recycled via lines 13 and 15 for use as a solvent in the extraction of subsequent batches of coal-tar material. The pitch residue obtained from this distillation via line 09 will have a substantially reduced viscosity, a lower average particle size of insolubles, in addition to a reduced Q.I. content.
The advantages accruing to the user of this pro-cess are many, not the least of which is the extent of the Q.I. removal from the coal-tar which results from the use of this process. Some of the other advantageous features of this process stem from the solvent system used in this pro-cess viz. the n-methyl-2-pyrrolidone and/or the light boil-ing cut of the tar distillate; in particular, the ease with which the solvent can be used, recovered, reused; and the facility with which these operations can be integrated into a conventional pitch production process.
A surprising outcome of this process is the manner in which the viscosity of the pitch and the size distribu~
tion of the Q.I~ is affected. The size distribution of a pitch derived from an unextracted tar, or one extracted with a solvent different from that of the present invention, is " ~73773 often characterized by a greater degree of particulate agglomeration. The pitch material thus obtained is charac-terized by a viscosity lower than that of pitches obtained by the distillation of the untreated coal tar. This is particularly important where the particulate size of the pitch is important e.g. in applications such as the impregnation of prebaked electrodes.
The following examples will serve to illustrate the invention.
Example 1 This example illustrates how the Q.I. of a conven-tional coal tar material can be decreased by the present invention using the light boilers of coal tar distillation (wash oil) as the solvent.
A sample of coal-tar having a Q.I. of 6.5~, and representative of the output obtained from steel mills was mixed with wash oil in a tar to wash oil ratio of 3:2. The mixture was filtered using a Buchner funnel and No. 1 analytical filter paper with a moderate vacuum being applied to accelerate the process. The Q.I. of the treated tar was measured. The filtrate was then distilled under atmo-spheric pressure, and the Q.I. content of the pitch residue determined in accordance with ASTM D2318. The experimental : recults are summarized in Table 1 below. The above proce-dure was repeated with two other commercially available coal tar samples having Q.I values of 7.0 and 23.7% respective-ly. In each of the cases, the Q.I. in the treated tar was a small fraction of that in the original sample.
A possibly more remarkable outcome which was in-dicative of the degree to which the process resulted in theQ.I. removal was the low Q.I. content in the pitch residue as compared to the original tar. This is surprising because Q.I. is hormally concentrated in the pitch, partly due to a 3~7~3 large decrease in the volume, and partly due to some crack-ing which occurs during the distillation. Nonetheless, in all the cases the Q.I. in the pitch was a small fraction of that in the tar prior to filtration.
i The above procedure was repeated with the same three tar samples, but with a tar:solvent ratio of 104. The experimental results which are qualitatively substantially the same as the preceding set; are also summarized in Table 1 below.
Table 1 _.~,. . .
, ., ,Q.I. (%) 'Coal Tar.Tar: Solvent'Untreated~ QoI~ (%) 'Q.I.(%) Sample ' Ratio . Tar ' (Treated Tar) '(Pitch) 1 , 3:2 '6.5 . 0.02 , 0.3 2 J 3:2 '7.0 ' 0.5 . 1.0 1 3 ' 3:2 '23.7 0.7 ~.5 ` ' 1 , 1:4 '6.5 ' 0.5 . 0.5 ' 2 ' 104 .7.0 ' 0.03 ' O.S g i 3 i 1:4 j23.7 ~ 0 3 i 3 0 Exam21e 2 This example illustrates the use of n-methyl-2-pyrrolidone as the solvent in the extraction of the Q.I.
from the tar, Tar samples identical to those in example 1 were subjected to essentially the same procedure and tests as~
described above in the preceding Example. The results of these experimental runs which are summarized in Table 2 below follow essentially the same pattern as in the preced ing Example. The treated tar has a greatly reduced Q.I.
which is also manifested in the low Q.I. content of the pitch residue remaining after the distillation of the tar.
3~7i73 Table 2 , Q.I. (%) l ' Coal Tar'Tar: Solvent'Untreated' Q.I. (%) 'Q.I.(%).
Sample ' Ratio ' Tar . (Treated Tar) '(Pitch)' 1 : 3:2 . 5.0 0.1 0.7 ' 2 ' 3:2 ' 4.2 ' 0.1 . 3.4 . 3 , 3:2 '18.2 ' 0.3 . 4.5 ,_ ., .. ._ , . ., . . , ~
1 , 1:4 , 5.0 0~2 , 1.3 2 ' 1:4 , 4.2 ' 0.1 ' 1.8 i 3 i 1:4 j18.2 , 0-03 i 5.1 . . . .
Example 3 This example presents a qualitative comparison of particle sizes of insolubles in tar which has been extracted using a conventional solvent (in this case quinoline), and that which is residual in E~ after an extraction of the precursor tar according to the present invention.
Figure 2(a) is a scanning electron microscope (S.B.M.) photograph of residual tar Q.I. following an extraction using quinoline. Figure 2(b) is a S.E.M. photo-graph of the insolubles in a pitch prepared from an identical tar after extraction with n-methyl-2-pyrrolidone.
It will readily moved that typical particle sizes in the former photograph are greater than about 1 micron, with sizes of the agglomerated particles ranging up to about
4 microns. The particle sizes in the latter photograph ~Fiyure 2(b)) range from less than about 0.~ microns to about 0.5 micron, with the larger agglomerates being about 1 micron in size.
The difference in the particle size distribution is all the more substantial when we note that the particles in latter photograph include not only the insolubles follow-ing the extraction of the tar, but additionally include the "secondary" Q.I. produced during the tar distillation to produce the pitch, where the original Q.I. is concentrated and function as nuclei for the growth of Q.I. particles.
_ g _ ~73~73 The above described procedure can be subjected to a great variety of modifications which will be evident to those skilled in the art and which fall within the scope of the appended claims.
The difference in the particle size distribution is all the more substantial when we note that the particles in latter photograph include not only the insolubles follow-ing the extraction of the tar, but additionally include the "secondary" Q.I. produced during the tar distillation to produce the pitch, where the original Q.I. is concentrated and function as nuclei for the growth of Q.I. particles.
_ g _ ~73~73 The above described procedure can be subjected to a great variety of modifications which will be evident to those skilled in the art and which fall within the scope of the appended claims.
Claims (10)
1. A process for decreasing the content of quinoline-insolubles (Q.I.) in coal-tar material which comprises: mixing said coal-tar material with a solvent which contains at least one of n-methyl-2-pyrrolidone and the fraction of a coal-tar distillate which boils between 100 and 350°C; thereby to form a solvent-dissolved fraction and a solvent-undissolved fraction, separating said solvent-dissolved fraction from said solvent-undissolved fraction of said coal-tar material, where said Q.I. is concentrated in said solvent-undissolved fraction and said solvent-dissolved fraction comprises coal-tar material with a decreased Q.I.
2. Process as defined in Claim 1, comprising the ad-ditional step of distilling said solvent-dissolved fraction of said coal-tar material so as to obtain a pitch material, where said pitch material has a lower Q.I. than pitch material obtained by the distillation of said coal-tar material.
3. Process as defined in Claim 2 wherein said distil-lation additionally serves to separate said solvent from said solvent-dissolved fraction.
4. Process as defined in Claim 3 wherein said sepa-rated solvent is used in the extraction of additional coal tar material.
5. Process as defined in Claims 1, 2 or 3, wherein the ratio of said solvent to said coal-tar material ranges from about 4:1 to about 1.4.
6. Process as defined in Claims 1, 2 or 3, wherein said mixing and separation steps are carried out at a tem-perature in the temperature range of 75 - 95 °C.
7. Process as defined in Claims 1, 2 or 3, wherein said separation is carried out by filtration of said mixture.
8. Process as defined in Claims 1, 2 or 3, wherein said separation is carried out by centrifugation of said mixture.
9. Process as defined in Claims 1, 2 or 3, wherein said separation is a gravity separation.
10. A product derived from coal tar material by the process defined in claims 1, 2 or 3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000377822A CA1173773A (en) | 1981-05-19 | 1981-05-19 | Process for modifying coal tar materials |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000377822A CA1173773A (en) | 1981-05-19 | 1981-05-19 | Process for modifying coal tar materials |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1173773A true CA1173773A (en) | 1984-09-04 |
Family
ID=4119983
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000377822A Expired CA1173773A (en) | 1981-05-19 | 1981-05-19 | Process for modifying coal tar materials |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1173773A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102492451A (en) * | 2011-12-13 | 2012-06-13 | 中国矿业大学 | Extracting and separating method of high-temperature coal tar |
| CN104164247A (en) * | 2014-06-12 | 2014-11-26 | 榆林学院 | Method for separating light component oil and solid slag from medium-low temperature heavy coal tar, and application of solid slag in bonding semi-coke to prepare briquette and formcoke by |
-
1981
- 1981-05-19 CA CA000377822A patent/CA1173773A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102492451A (en) * | 2011-12-13 | 2012-06-13 | 中国矿业大学 | Extracting and separating method of high-temperature coal tar |
| CN104164247A (en) * | 2014-06-12 | 2014-11-26 | 榆林学院 | Method for separating light component oil and solid slag from medium-low temperature heavy coal tar, and application of solid slag in bonding semi-coke to prepare briquette and formcoke by |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| DE3012627C2 (en) | ||
| DE2456575C2 (en) | Process for the production of electrode coke | |
| US4604184A (en) | Modified coal-tar pitch | |
| DE3116606C2 (en) | ||
| US2774716A (en) | Process for removing finely divided solids from raw low temperature carbonization coal tars | |
| US4517072A (en) | Process for modifying coal tar materials | |
| US3010893A (en) | Method for removing finely divided solid particles from low temperature carbonization tars | |
| EP0119273B1 (en) | Process for producing pitch | |
| EP0232481B1 (en) | Process for fractionating coal tar and use of the obtained fractions | |
| DE2510539A1 (en) | COAL LIQUID | |
| US4402824A (en) | Process for refining coal-based heavy oils | |
| CA1173773A (en) | Process for modifying coal tar materials | |
| EP0097755B1 (en) | Process for modifying coal tar materials | |
| DE3606397C2 (en) | ||
| DE2853366C2 (en) | ||
| US4101413A (en) | Extraction of coal | |
| EP0135943B1 (en) | Process for separating resinous materials from heavy coal oils, and use of the fractions so obtained | |
| SE460361B (en) | PROCEDURES FOR SEPARATION OF WATER AND SOLID PARTS FROM BRAENSLE, SPECIAL SHIFT OIL | |
| DE2624389A1 (en) | METHOD FOR PRODUCING COCK | |
| SU1271374A3 (en) | Method of separating quinolin-insoluble substances from coal products | |
| EP0283584B1 (en) | Process for reducing the water and ash content in crude tar | |
| CA1055250A (en) | Process for the production of ashless liquid fuels | |
| US2964460A (en) | Liquid carbon black feedstock | |
| JPH0222787B2 (en) | ||
| DE3112004C2 (en) | Process for refining heavy oils derived from coal |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |