KR101677296B1 - Method for Preparing Coal Tar Pitch Having Improved Compatibility with Asphalt and Asphalt Containing the Same - Google Patents

Abstract

A concrete example according to the present invention relates to a technique for producing a coal tar pitch for road pavement by mixing coal tar pitch with asphalt and an asphalt containing the coal tar pitch, The present invention relates to a technique for producing a coal tar pitch and an asphalt containing the coal tar pitch and the asphalt using the aromatic content rich oil to prevent the increase of the content and the material separation phenomenon. The above-mentioned coal tar pitch-containing asphalt is highly likely to be used as a material for road pavement.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a coal tar pitch having improved compatibility with asphalt, and a method of manufacturing asphalt containing same.

The present invention relates to the production of coal tar pitch-containing asphalt which is suitable as a coal tar pitch and road pavement material which improves the compatibility with asphalt using an aromatic oil fraction.

Asphalt has been used for road pavement since BC 13, and since the end of the 19th century, the demand for asphalt pavement, which is a byproduct of the oil refinery, has been rapidly increasing due to the introduction and spread of the refinery process. Currently, most of the world's roads are paved with asphalt, and there will be no major changes in the years ahead. However, the supply of asphalt for road paving is expected to decline in the long term, as petroleum is getting depleted and oil prices are expected to continue rising, and the upgrading process of converting relatively low-priced asphalt to high-value fuel oil is being applied do.

There are many studies to develop materials that can replace asphalt, but there is no alternative to replace asphalt which is used in large quantities. In the early 20th century when asphalt supply was inevitable, coal tar was used as an asphalt pavement material. In Sweden and other countries, tens of millions of tons of coal tar was used for road pavement. However, since the mid-20th century, coal tar has not been used for pavement due to increased asphalt production, ease of supply, and excellent price performance.

Recently, research on coal tar which can be mass-used as a substitute material for the lack of asphalt resources has been under way. In particular, coal tar pitch produced by distillation of coal tar has similar physico-chemical properties as asphalt, Some studies have been carried out to manufacture asphalt for road pavement by mixing with asphalt. However, the coal tar pitch contains a large amount of trichlorethylene insoluble matter, that is, an insoluble matter insoluble in trichlorethylene, as defined in ASTM D2042-09 as a major requirement for asphalt, so that the insoluble content content of asphalt when mixed with asphalt exceeds the quality standard . In addition, when coal tar pitch and asphalt are mixed and stored at high temperature (for example, 150 ° C), material separation phenomenon occurs. This is because the coal tar pitch destroys the stable equilibrium structure inside the asphalt so that the asphalt component of the asphalt and the high boiling point fraction of the coal tar pitch are aggregated and separated. Therefore, in order to be used as road pavement asphalt, it is essential to remove trichlorethylene insoluble matter and improve compatibility with asphalt.

Few studies have been made to reduce trichlorethylene insoluble matter in coal tar pitches, but studies on the reduction of toluene or quinoline insolubles in the pitch have been described in US Pat. No. 4,402,824. This patent discloses a method for producing a coal tar pitch having a low content of toluene insolubles by distilling the supernatant liquid except the precipitated insoluble matter by atmospheric and vacuum distillation after mixing solvents such as ketones into coal tar and precipitating the toluene insoluble matter through centrifugation . In addition, US Pat. No. 4,640,761 suggests that toluene insolubles can be reduced when centrifuging coal tar at high temperatures.

However, the existing toluene insolubles abatement patents have no direct correlation with the reduction of trichlorethylene insolubles, which is a measure of asphalt purity. Also, since these patents are not a technique considering improvement of mixing with asphalt, it is not easy to improve the mixing property with asphalt only by the coal tar pitch in which only the toluene insoluble matter is removed. Therefore, in order to easily mix the coal tar pitch with the asphalt, it is necessary to improve the mixing performance with the asphalt as well as the trichlorethylene insolubility of the coal tar pitch.

The present invention relates to a process for producing asphalt containing a coal tar pitch wherein the content of trichlorethylene insoluble matter is reduced during the production of coal tar pitch and the coal tar pitch is mixed with asphalt to prevent material separation during high temperature storage And a process for producing asphalt containing the same.

According to a first aspect of the present invention, there is provided a method of manufacturing a coal tar pitch,

a) mixing (i) naphtha cracked residual oil or slurry oil, and (ii) coal tar in a weight ratio of 1: 1 to 1: 8;

b) distilling the mixture at atmospheric pressure in the range of from 200 to 250 < 0 >C; And

c) distilling the residue of the residue obtained in the above-mentioned atmospheric distillation step at a temperature of 330 to 380 ° C under reduced pressure.

According to a second aspect of the present invention,

The step (a) may be carried out by further containing a ketone-based solvent, wherein the weight ratio of components (i) and (ii) to the ketone-based solvent may be 2 to 9.

The method for manufacturing asphalt according to the third aspect of the present invention comprises mixing the coal tar pitch and the petroleum-based asphalt produced by the above-described production method at a weight ratio of 1: 2 to 1: 9.

As a result, it is possible to obtain a more economical pavement material because it can be used in combination with asphalt inexpensively with a lower coal tar pitch than the asphalt through the concrete example according to the present invention, thereby contributing to securing alternative raw materials for the reduction of the asphalt production amount in the future.

The present invention can be achieved by the following description. It is to be understood that the following description is of a preferred embodiment of the present invention and that the present invention is not necessarily limited thereto.

According to the embodiment of the present invention, in order to reduce the insoluble content of coal tar pitch and to improve the mixing property of asphalt and coal tar pitch, naphtha decomposition residue oil and slurry oil, which are byproducts generated in the petrochemical process and refinery process, A process for producing a coal tar pitch by an atmospheric distillation and a vacuum distillation process, and a process for producing an asphalt containing a coal tar pitch produced by the above process.

The naphtha-decomposed residual oil which can be used in the embodiment of the present invention may be a blackish brown residual oil produced by decomposing naphtha and producing olefins such as ethylene, propylene and butadiene, And may contain an aromatic hydrocarbon as a main component. Wherein the naphtha cracked residual oil has a boiling point of from about < RTI ID = 0.0 > 150 C & Lt; 0 > C, and may range from about 250 < 0 > C to about 500 Lt; 0 > C may be more preferable. The content range of the aromatics (specifically, the aromatic hydrocarbon having 10 or more carbon atoms) of the naphtha-decomposed residual oil may be, for example, about 80% by weight or more, and more preferably about 85% by weight or more. The above-described numerical ranges are described for illustrative purposes only, and the present invention is not limited thereto.

The slurry oil which can be used in the embodiment of the present invention may be oil produced as a by-product in the heavy oil contact cracking process during the refining process. At this time, the heavy oil contact cracking process is performed by using Vacuum Gas Oil (VGO), Atmospheric Residual Oil (AR), their hydrodesulfurization oil, or a mixture thereof as raw materials, And decomposing the gasoline to produce a gasoline which is a light oil. Among the semifinished products produced at this time, slurry oil, which is the bottom oil fraction obtained particularly later, can be used.

In particular, slurry oils which may be used in embodiments of the present invention may be, for example, those having a boiling point within the range of from about 250 ° C to about 650 ° C and preferably within the range of from about 350 ° C to about 560 ° C . The exemplary composition of the slurry oil may also include about 10 to about 25 weight percent saturated hydrocarbon and about 75 to about 90 weight percent aromatics, .

According to an exemplary embodiment of the present invention, first the naphtha cracked residual oil or slurry oil, and the coal tar are mixed. At this time, it may be preferable that the mixing step is performed under agitation (for example, about 100 to about 1,000 rpm, preferably about 200 to about 500 rpm).

(Or mixture) obtained from the above-mentioned mixing step is subjected to atmospheric distillation at a temperature in the range of about 200 to about 250 DEG C, and then the residue oil obtained from the atmospheric distillation distillation step is distilled at about 330 to about 380 Lt; 0 > C to recover the coal tar pitch as residue oil.

In this embodiment, the mixing ratio (by weight) of (i) naphtha cracked residual oil or slurry oil and (ii) coal tar is in the range of about 1: 1 to about 1: 8 (component (i): component May be preferred, and a range of about 1: 2 to about 1: 4 may be more preferred. However, when the amount of coal tar is low, it may be undesirable from the viewpoint of improving the economic efficiency due to utilization of coal tar. On the other hand, when the amount of coal tar is excessively large, the coal tar pitch reforming effect by the naphtha- . Thus, it may be desirable to adjust to the mixing ratio range described above.

According to another exemplary embodiment of the present invention, in addition to the coal tar and naphtha decomposition residue or slurry oil, a ketone-based solvent may be further added to form a mixture. At this time, the usable ketone-based solvent may have a boiling point of, for example, about 200 캜 or less. Examples of the ketone solvents include acetone, methyl ethyl ketone, diethyl ketone, pinacolone, isobutyl methyl ketone, diisopropyl ketone, methyl butyl ketone, dipropyl ketone, methyl vinyl ketone, methyl heptanone, cyclopentanone, Saturated or unsaturated ketone compounds such as acetone, methyl ethyl ketone, ethyl methyl ketone, hexyl methyl ketone, and the like can be used, and these can be used alone or in combination. It may be desirable to apply acetone, methyl ethyl ketone, or mixtures thereof in the illustrated ketone solvents.

According to an exemplary embodiment, the ketone-based solvent described above is mixed with the coal tar and the naphtha decomposition residue or slurry oil under agitation (from about 100 to about 1,000 rpm, preferably from about 200 to about 500 rpm) (For example, about 1,000 to about 10,000 rpm, preferably about 2,000 to about 5,000 rpm) is centrifuged to remove the sludge that has settled on the bottom of the centrifuge tube. The supernatant is subjected to atmospheric distillation do. The residue oil obtained from the atmospheric distillation step is then heated to a temperature of from about 330 to about 380 Deg.] C to recover the pitch as residue oil.

According to another exemplary embodiment of the present invention, in the above mixing step, the coal tar and the ketone solvent are first mixed and centrifuged (for example, about 1,000 to about 10,000 rpm, preferably about 2,000 to about 5,000 rpm )do. The naphtha decomposition residue or slurry oil is added to the supernatant liquid except for the sludge which has settled on the bottom of the centrifuge tube, and the atmospheric distillation is carried out in the range of about 200 to about 250 ° C. Thereafter, the residue oil obtained in the above atmospheric distillation step is heated to a temperature of about 330 to about 380 Lt; 0 > C to recover the coal tar pitch as residue oil.

In this embodiment, the weight ratio of the coal tar and naphtha decomposition residue or slurry oil to the ketone-based solvent may range from about 2 to about 9, and preferably from about 2 to about 4. In this connection, the solvent recovery cost can be increased as the amount of the ketone solvent is increased. On the other hand, when the amount of the ketone solvent is less than the proper amount, the effect of increasing the efficiency of separation of the trichlorethylene insoluble matter contained in the coal tar It may not be enough. Therefore, the mixing ratio range described above may be preferable.

The coal tar pitch produced as described above can be mixed with petroleum based asphalt to produce asphalt containing the coal tar pitch. Wherein the mixing step is from about 130 to about 180 < RTI ID = 0.0 > Deg.] C, and may also be carried out under stirring (from about 100 to about 1,000 rpm, preferably from about 200 to about 500 rpm).

Examples of the petroleum-based asphalt which can be used in the embodiment of the present invention include straight products such as straight asphalt, asphalt cement, cutback asphalt, emulsified asphalt, Blown asphalt, modified asphalt, and the like. Typically, the dynamic viscosity (60 캜) may range from about 1 x 10 ^-3 to about 1 m ² / s and the penetration according to ASTM D-5 (25 캜) ranges from about 5 to about 400 Can be used. Also, it may have a flash point (COC system, ASTM D-92) of at least about 280 캜 and an asphaltene content of about 2 to about 30% by weight as measured according to ASTM D 4142.

The mixing ratio (weight ratio) of the coal tar pitch and petroleum based asphalt may range from about 1: 2 to about 1: 9 (coal tar pitch: petroleum based asphalt), preferably from about 1: 2 to about 1: As the amount of the petroleum-based asphalt used decreases, the relative content of the coal tar pitch having different chemical characteristics from that of the asphalt increases, and it may be difficult to meet the road asphalt standard. On the other hand, when the petroleum-based asphalt is used in an excessively large amount, the effect of replacing the asphalt material due to the coal tar pitch blending may not be significant. In view of the above, it is preferable to maintain the mixing ratio range described above.

Hereinafter, the technical idea of the present invention will be specifically described by way of Examples and Experimental Examples, but the present invention is not limited to the following contents.

Evaluation of Mixability

The mixture was stored in an oven at 150 ° C for 2 days and then visually evaluated. In addition, the tube test method prescribed in AASHTO PP5 was improved to quantitatively evaluate the mixing properties, and the storage conditions of the sample were set more strictly. Specifically, 55 g of a sample was put into an aluminum tube having a diameter of 25 mm and a length of 140 mm, and then stored in an oven at 163 ° C for 3 days. Thereafter, the tube cooled at room temperature was divided into three equal parts, and the contents of insoluble trichlorethylene in the upper and lower samples were measured.

Example  One

After the atmospheric distillation at 250 ° C., the crude distillate residue was distilled off at 360 ° C. under reduced pressure at a temperature of 360 ° C. The resulting mixture was subjected to distillation under the same conditions as in Example 1 except that the mixed liquor 1 (coal tar: naphtha decomposition residue = 5: 1), mixed liquor 2 (coal tar slurry oil = And the coal tar pitch was recovered by distillation. The thus obtained coal tar pitch and petroleum-based asphalt (AP-5, SK Energy Co., Ltd.) were mixed under the stirring conditions of 150 캜 and 300 rpm in a ratio (weight ratio) of 5 (asphalt) Asphalt was prepared. The content of trichlorethylene insoluble matter in the coal tar pitch and the physical properties of the asphalt containing the coal tar pitch were measured and are shown in Tables 1 and 2 below.

Contrast ratio of trichlorethylene insoluble content of three kinds of coal tar pitch division Trichlorethylene insoluble matter content (% by weight) Mixed solution 1 7% Mixed solution 2 7% Raw coal tar 25%

Properties of three kinds of asphalt containing pitch division Trichlorethylene insoluble matter content, wt% After storing at 150 ℃ for 2 days
Visual observation Mixability
(Tube test method),% Mixed solution 1 0.9% No material separation phenomenon 1.1 Mixed solution 2 1.0% No material separation phenomenon 0.8 Raw coal tar 5.2% A significant amount of sediment 8.7

As can be seen from Tables 1 and 2, the coal tar pitch obtained by mixing naphtha-decomposed residual oil and slurry oil with coal tar and distilling (atmospheric distillation and reduced pressure distillation) had a trichlorethylene insoluble matter content Showed markedly reduced properties. In addition, in the case of the coal tar pitch-containing asphalt prepared by mixing the coal tar pitch and the asphalt according to the present embodiment, the material separation phenomenon occurring in ordinary coal tar pitch-containing asphalt was not observed even when stored for a long period at a high temperature.

Example  2

And a mixed solution 5 (coal tar: acetone = 5: 1), and a coal tar slurry (coal tar slurry: acetone = 5: 1: 1) Each of the stock solutions was centrifuged at 3,000 rpm, and the supernatant, from which the precipitate was removed, was distilled at atmospheric pressure at 250 ° C. The residual oil in the above atmospheric distillation step was subjected to vacuum distillation at 360 ° C to obtain a coal tar pitch. The coal tar pitch and the petroleum-based asphalt (AP-5, SK Energy Co., Ltd.) thus prepared were mixed under the stirring conditions of 150 캜 and 300 rpm in a ratio (weight ratio) of 5 (asphalt) Containing asphalt. The trichlorethylene insoluble content in the coal tar pitch and the physical properties of the asphalt containing the coal tar pitch were measured and shown in Tables 3 and 4 below.

Contrast ratio of four types of trichloroethylene insolubles in coal tar pitch division Trichlorethylene insoluble matter content (wt%) Mixed solution 3 3% Mixed solution 4 3% Mixed solution 5 4% Raw coal tar 22%

Properties of four kinds of asphalt containing pitch division Trichlorethylene insoluble matter
Content (% by weight) After storing at 150 ℃ for 2 days
Visual evaluation Mixability
(Tube test method),% Mixed solution 3 0.2% No material separation phenomenon 0.3 Mixed solution 4 0.2% No material separation phenomenon 0.6 Mixed solution 5 One% A small amount of sediment 1.3 Raw coal tar 4.8% A significant amount of sediment 6.8

As can be seen from Tables 3 and 4, the coal tar pitch obtained by mixing the naphtha-decomposed residual oil and the slurry oil with a coal tar and ketone solvent and performing distillation (atmospheric distillation and reduced pressure distillation) after centrifugation, The content of trichlorethylene insoluble matter was remarkably decreased. In addition, according to this example, in the case of the coal tar pitch-containing asphalt prepared by mixing the coal tar pitch and the asphalt, the material separation phenomenon occurring in ordinary coal tar pitch-containing asphalt was not observed even when stored for a long period at a high temperature.

However, as in US Pat. No. 4,402,824, the content of trichlorethylene insoluble matter in the coal tar pitch obtained by distillation through centrifugation after mixing only ketone solvent and coal tar was greatly reduced, but material separation occurred when mixed with asphalt.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. In particular, the present invention is not necessarily limited to aspects preferred or particularly mentioned as being advantageous. Accordingly, it is intended that the present invention cover the modifications and variations of this invention that come within the scope of the following claims and their equivalents.

Claims (9)

a) mixing (i) naphtha cracked residual oil or slurry oil, and (ii) coal tar in a weight ratio of 1: 1 to 1: 8;
b) distilling the mixture at atmospheric pressure in the range of from 200 to 250 < 0 >C; And
c) distilling the residue of the residue obtained in said atmospheric distillation step at a temperature of 330 to 380 ° C;
≪ / RTI > The method for producing a coal tar pitch according to claim 1, wherein the weight ratio of (i) the naphtha-decomposed residual oil or slurry oil and (ii) the coal tar is in the range of 1: 2 to 1: 4. The naphtha cracked residue oil according to claim 1, wherein the naphtha cracked residual oil is a residual oil produced as a by-product in the process of decomposing naphtha to produce olefins, wherein the content of aromatic hydrocarbons having a carbon number of 10 or more is 80% ≪ / RTI > The slurry oil according to claim 1, wherein the slurry oil is oil produced as a by-product in the heavy oil contact cracking process during the refining process, and has boiling points in the range of 250 to 650 ° C and contains 10 to 25% by weight of saturated hydrocarbons and 75 to 90% Wherein the method comprises the steps of: The method according to claim 1, wherein the step (a) is carried out further comprising a ketone-based solvent, and the weight ratio of the components (i) and (ii) to the ketone- ≪ / RTI > 6. The method of claim 5, wherein the ketone-based solvent is selected from the group consisting of acetone, methyl ethyl ketone, and mixtures thereof. [7] The method of claim 5, wherein the step a) comprises mixing the naphtha-decomposed residual oil or the slurry oil with the supernatant obtained by mixing the coal tar and the ketone-based solvent and then removing the sludge by centrifugal separation A method for producing a coal tar pitch. 7. A method for producing a coal tar pitch-containing asphalt comprising the step of mixing coal tar pitch produced according to any one of claims 1 to 7 and petroleum asphalt at a weight ratio of 1: 2 to 1: 9. The method as claimed in claim 8, wherein the mixing step is performed at a temperature of 130 to 180 ° C and a stirring condition of 100 to 1,000 rpm.