KR102380530B1 - Method for preparing purified pitch from heavy tar - Google Patents

Abstract

The present invention is a method of obtaining a raw material for a high value-added carbon material by refining heavy tar, and in detail, the present invention comprises the steps of: preparing a heavy tar solution by dissolving the heavy tar in an organic solvent; obtaining a liquid filtrate by solid-liquid separation of the heavy tar solution; removing the organic solvent from the liquid filtrate; solid-liquid separation of the filtrate from which the organic solvent has been removed to obtain purified tar; It provides a method for producing refined pitch from heavy tar, comprising the step of preparing a refined pitch by distilling the refined tar.

Description

Method for preparing purified pitch from heavy tar

The present invention relates to a method for manufacturing refined pitch from heavy tar, which is generated during the refining process of coke oven gas (COG) in order to produce refined pitch, which is a raw material for high value-added carbon products such as needle-like coke. It relates to a method for refining heavy tar.

A large amount of coal tar is generated as a by-product during the refining of coke oven gas during the steelmaking process, and coal tar is a material closely used in the fine chemical and carbon material industries.

On the other hand, coal tar can generally produce tar oil, which is a raw material in the fine chemical industry, through a distillation process, which is divided into light oil (BTX), phenol, quinoline, wash oil, creosote oil, etc. by distillation temperature. can be used by Furthermore, in the field of carbon materials, using the pitch remaining after distilling coal tar, binder pitch, impregnated pitch, needle coke, pitch coke, etc. are produced and processed into final products such as isotropic graphite blocks, electrode rods, and carbon fibers.

As such, coal tar is used as a core raw material in various industrial fields, but since it is generated as a by-product, there is a limit to artificially and mass-added production. Therefore, a plan to utilize the heavy tar generated at the same time during the coal tar production process has emerged. For this purpose, techniques for recovering heavy tar in the coke manufacturing process are being studied as in Korean Patent Application Laid-Open No. 2005-0006676.

However, heavy tar is sludge that settles at the bottom of the tar decanter in the process of separating moisture by standing still in coal tar. It cannot be sold as a general coal tar product due to high moisture and sticky impurities in the form of lumps, ash, etc., and naphthalene It was sold for recovery and fuel use. Therefore, research on the commercialization of more high value-added products has hardly been conducted, and a technology capable of refining/separating heavy tar into a substance such as coal tar and utilizing it is required.

The present invention is capable of manufacturing refined pitch, which is a raw material for high value-added carbon products by refining heavy tar, and by applying specific process conditions to heavy tar, the contents of quinoline insoluble (QI) and ash (Ash) are reduced to zero. It aims to manufacture a refined pitch.

In one aspect of the present invention, the present invention comprises the steps of dissolving heavy tar in an organic solvent to prepare a heavy tar solution; obtaining a liquid filtrate by solid-liquid separation of the heavy tar solution; removing the organic solvent from the liquid filtrate; solid-liquid separation of the filtrate from which the organic solvent has been removed to obtain purified tar; And it provides a method for producing a refined pitch from heavy tar, comprising the step of preparing a refined pitch by distilling the refined tar.

According to the present invention, it is possible to obtain refined tar and refined pitch having little impurity content by refining heavy tar having high viscosity and having many impurities such as ash and quinoline insoluble matter. The refined pitch may be used to manufacture a carbon material, and further, an extraction process for removing quinoline insoluble content may be omitted during manufacturing of the existing needle-shaped coke.

Embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

The present invention provides a method for obtaining refined tar and refined pitch that can be used in the fine chemical field or carbon material field by refining heavy tar to provide a method for manufacturing refined tar and refined pitch.

Specifically, the present invention comprises the steps of dissolving heavy tar in an organic solvent to prepare a heavy tar solution; obtaining a liquid filtrate by solid-liquid separation of the heavy tar solution; removing the organic solvent from the liquid filtrate; solid-liquid separation of the filtrate from which the organic solvent has been removed to obtain purified tar; And it provides a method for producing a refined pitch from heavy tar, comprising the step of preparing a refined pitch by distilling the refined tar.

The heavy tar is sludge that is precipitated at the bottom of the tar decanter in the process of separating moisture by standing coal tar, and contains high moisture and sticky impurities and ash in the form of lumps. For example, the heavy tar contains 0.2% by weight or more of ash and 3% by weight of quinoline insoluble matter (QI) based on the total weight of the heavy tar, and may have a viscosity of 1,000cP or more and a specific gravity of 1.20 or more, Preferably, it contains 0.2 to 3.0 wt% of ash (Ash) and 3 to 15 wt% of quinoline insoluble matter (QI), and may have a viscosity of 1,000 to 4,000 cP and a specific gravity of 1.20 to 1.25.

In general, the raw material used in the needle coke manufacturing process preferably has a viscosity of 100 cP or less and a specific gravity between 1.16 and 1.20 at room temperature. However, when the content of ash and quinoline insolubles in the raw material is high, it interferes with the growth of needle crystals when manufacturing high value-added carbon materials such as needle coke.

Therefore, when a carbon material is manufactured using a raw material with a high content of ash and quinoline insoluble matter, when a product of a certain size or larger is produced, the yield decreases and strength is weakened, and crystal growth is not sufficient. As a result, the electron flow characteristics are not good and the specific electrical resistance is high, which may cause functional problems when used as a final product such as an electrode. Therefore, in order to use heavy tar as a raw material for manufacturing a carbon material, it is necessary to control the content of ash and quinoline insoluble matter.

On the other hand, when the ash content is less than 0.2% by weight and the quinoline insoluble content is less than 3% by weight, it is possible to sufficiently control the purification method in the needle coke manufacturing process without following the method used in the present invention. On the other hand, when the content of ash is 3.0% by weight or more and the content of quinoline insolubles is 15% by weight or more, in the step of obtaining a liquid filtrate by solid-liquid separation of the heavy tar solution of the present invention, heavy and insoluble substances in organic solvents By blocking, the solid-liquid separation takes a long time, and it may have the opposite effect of filtering even the substances in the beta resin area that help form acicular coke.

Furthermore, in the case of viscosity and specific gravity, the values should be managed in order to facilitate input and discharge of each process as a raw material rather than a problem that occurs when manufacturing products using refined tar or refined pitch obtained after refining. For example, tar with a viscosity of 4,000 cP or more and a specific gravity of 1.25 or more at room temperature can cause a pipe clogging phenomenon even if a series of process conditions that increase the temperature in the needle coke manufacturing process are changed, causing a huge disruption in product production. .

Next, the heavy tar purification method of the present invention will be described in detail.

Since the heavy tar of the present invention may undergo phase separation, the step of preparing a uniform heavy tar using a device such as a homomixer may be performed. For example, the present invention may further include the step of pulverizing the heavy tar before adding the organic solvent, thereby preparing a uniform heavy tar.

In the present invention, an organic solvent may be used to purify heavy tar into refined tar, and Tetra Hydro Furan (THF) may be used as the organic solvent. THF is a polar solvent with a tar dissolution rate of 90% or more, and has an advantage that it can be reused through distillation because it has a low boiling point of 66°C. Therefore, in the present invention, a heavy tar solution can be prepared by adding THF to the heavy tar and stirring.

Furthermore, the present invention may be used by mixing the organic solvent in an amount of 50 to 100 parts by weight, preferably 70 to 100 parts by weight, based on 100 parts by weight of heavy tar. If the amount of the organic solvent used is less than 50 parts by weight, the heavy tar is not completely dissolved in the organic solvent and becomes a viscous mixed solution. Since substances corresponding to the affected beta resin area are filtered, the yield and physical properties of the product are deteriorated. On the other hand, when it exceeds 100 parts by weight, the dispersibility of the particles increases due to the low viscosity and concentration of the heavy tar solution, and it is difficult to remove ash or quinoline insoluble content below a certain level.

Next, the present invention can obtain a liquid filtrate by solid-liquid separation of the heavy tar solution. For example, the solid-liquid separation may be performed through a vacuum filtration device such as filtering, but is not limited thereto. For example, the filtering may be performed using a filter of 1250 to 2500 mesh in a vacuum filtration device.

However, the solid-liquid separation is preferably performed in a temperature range of 30 to 50 °C. If the temperature is less than 30 ℃, the mixture may be cooled in the filtration process to cause a decrease in yield, and if it is 50 ℃ or more, quinoline insoluble components are dissolved and proper filtration cannot be performed.

Furthermore, in the present invention, distillation may be performed to remove the organic solvent from the liquid filtrate. The distillation conditions are not limited, but it is preferable to carry out the distillation at a temperature of 70° C. or less. This is because, when the distillation temperature exceeds 70° C., light substances in the tar component are removed together, and the physical properties of the refined tar may change.

Next, purified tar can be obtained by solid-liquid separation of the filtrate from which the organic solvent has been removed. The solid-liquid separation may be performed using a method such as centrifugation, and through the solid-liquid separation, tar satisfying the content, specific gravity and viscosity of tar ash and quinoline insoluble matter used as a raw material for carbon material can be obtained. there is.

The centrifugation is not limited to the type or method, but may preferably be performed at a rotation speed of 1,000 to 2,500 RPM and a residence time of 40 to 120 seconds. If the rotational speed is less than 1,000RPM or the residence time is less than 40 seconds, there may be a problem that the quinoline insoluble content and ash component in the tar are not properly separated and remain, and if the rotational speed exceeds 2,500RPM or the residence time is If the time exceeds 120 seconds, there is no problem in the separation of quinoline insoluble content and ash, but it is not very efficient compared to the conditions presented in the present invention.

Furthermore, in the present invention, distillation may be performed to obtain a refined pitch from the refined tar. The distillation may be performed at a temperature of 300 to 360° C., for example, by distilling to an overhead temperature of 300 to 360° C. using a 15-stage packed column to obtain a purified pitch.

The yield of obtaining refined pitch from heavy tar by the method of the present invention is at a level of about 25 to 35%, and the refined pitch has mostly removed ash and quinoline insoluble content, and beta resin is also about 10% of carbon material such as needle coke. enough to be used as a raw material for For example, the tablet pitch is 0.03 wt% or less of ash (Ash) and 0.1 wt% or less of quinoline insoluble content (QI) based on the total weight of the tablet pitch, and may have a specific gravity of 1.23 or more.

Therefore, the present invention can manufacture a refined pitch that can be used as a raw material for a high value-added carbon material by removing most of the ash and quinoline insoluble content from heavy tar, which has many impurities and high viscosity, which has limited usability. Furthermore, for example, when producing needle-like coke, there is no need to perform a process (QI-Free extraction process) for removing quinoline insoluble content.

Hereinafter, the present invention will be described in more detail through specific examples. The following examples are only examples to help the understanding of the present invention, and the scope of the present invention is not limited thereto.

Example

Example 1

Based on the total weight of the heavy tar, use a homomixer to prepare a homogeneous sample of 2,000 g of inhomogeneous heavy tar of 3.0% by weight of ash, 15% by weight of quinoline insoluble matter (QI), 4,000 cP in viscosity, and 1.25 in specific gravity. did As an organic solvent, 100 parts by weight of a THF solvent per 100 parts by weight of the sample was added thereto, and stirred at a temperature of 50° C. for about 30 minutes to prepare a heavy tar solution.

After the heavy tar solution was filtered with a vacuum filtration device while maintaining the temperature at 50° C., a liquid filtrate (THF-Soluble tar layer) was obtained, and the residual THF of the liquid filtrate was removed using a rotary evaporator. Furthermore, to remove Ash and QI after removing residual THF, purified tar was obtained by centrifugation at 1,500 rpm and a residence time of 70 seconds to additionally remove Ash and QI (solid form such as sludge).

The purified tar was distilled by heating at atmospheric pressure (1 atm) so that the top temperature was 330°C. As a result, tar oil was separated, and refined pitch (residue remaining after distillation) was prepared with controlled ash, QI, beta resin, and specific gravity. The analysis results of the heavy tar, refined tar, and refined pitch are shown in Table 1.

Comparative Example 1

Ash 3.0% by weight, QI 15% by weight, viscosity 4,000cP, and heterogeneous heavy tar of 1.25% by weight of Ash used in Example 1, 4.0% by weight of Ash, 20% by weight of QI, viscosity 6,000cP, heterogeneous heavy tar with specific gravity of 1.28 A refined pitch was prepared through the same manufacturing process as in Example 1, except that tar was used. The analysis results of the heavy tar, refined tar, and refined pitch are shown in Table 1.

Comparative Example 2

The heterogeneous heavy tar of 3.0% by weight of Ash, 15% by weight of QI, viscosity 4,000cP, and specific gravity of 1.25 used in Example 1 was mixed with 0.15% by weight of ash, 2.5% by weight of QI, 800cP viscosity, and 1.19% by weight of heterogeneous heavy tar. A tablet pitch was prepared through the same manufacturing process as in Example 1, except that The analysis results of the heavy tar, refined tar, and refined pitch are shown in Table 1.

Comparative Example 3

A purified pitch was prepared through the same manufacturing process as in Example 1, except that the organic solvent THF used in Example 1 was used in an amount of 50 parts by weight per 100 parts by weight of the sample. The analysis results of the heavy tar, refined tar, and refined pitch are shown in Table 1.

Comparative Example 4

In Comparative Example 1, except for using 50% by weight of absorption oil (a liquid mixture consisting of methylnaphthalene, used as a solvent for extracting aromatic compounds such as benzene, toluene, and xylene) instead of the organic solvent THF used in Comparative Example 1 Purified pitch was prepared through the same manufacturing process. The analysis results of the heavy tar, refined tar, and refined pitch are shown in Table 1.

Comparative Example 5

Instead of the filtration temperature of 50 ° C in Example 1, a purified pitch was prepared through the same manufacturing process as in Example 1, except that it was carried out at a temperature of 20 ° C. The analysis results of the heavy tar, refined tar, and refined pitch are shown in Table 1.

Comparative Example 6

A purified pitch was prepared through the same manufacturing process as in Example 1, except that it was carried out at a temperature of 60°C instead of 50°C at the filtration temperature in Example 1. The analysis results of the heavy tar, refined tar, and refined pitch are shown in Table 2.

Comparative Example 7

A purified pitch was prepared through the same manufacturing process as in Example 1, except that in Example 1, the centrifugation conditions were performed at 1,000 rpm and a residence time of 40 seconds. The analysis results of the heavy tar, refined tar, and refined pitch are shown in Table 2.

Comparative Example 8

In Example 1, a refined pitch was prepared through the same manufacturing process as in Example 1, except that instead of performing the refined tar at a top temperature of 330° C., it was performed at a top temperature of 365° C. The analysis results of the heavy tar, refined tar, and refined pitch are shown in Table 1.

division Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 heavy tar QI (wt%) 15.0 20.0 2.5 15.0 15.0 15.0 Ash (wt%) 3.0 4.0 0.15 3.0 3.0 3.0 importance 1.25 1.28 1.19 1.25 1.25 1.25 Viscosity (cP) 4,000 6,000 800 4,000 4,000 4,000 refined tar QI (wt%) 0.02 0.1 0.09 0.11 1.94 0.06 TI (wt%) 3.8 4.5 4.0 5.0 8.5 2.8 Beta resin (wt%) 3.8 4.4 3.9 4.9 6.5 2.7 Ash (wt%) 0.01 0.1 0.09 0.11 0.21 0.01 importance 1.160 1.163 1.161 1.164 1.170 1.155 Viscosity (cP) 50 80 65 89 105 20 refined pitch transference number(%) 30 27 31 22 14 12 QI (wt%) 0.1 0.4 0.4 0.6 2.2 0.15 TI (wt%) 10.0 10.5 9.9 9.8 10.0 6.5 Beta resin (wt%) 9.9 10.1 9.5 9.2 7.8 6.35 Ash (wt%) 0.03 0.1 0.09 0.13 0.40 0.07 importance 1.240 1.242 1.243 1.248 1.250 1.235 Softening Point (℃) 60 62 63 65 67 58 division Comparative Example 6 Comparative Example 7 Comparative Example 8 heavy tar QI (wt%) 15.0 15.0 15.0 Ash (wt%) 3.0 3.0 3.0 importance 1.25 1.25 1.25 Viscosity (cP) 4,000 4,000 4,000 refined tar QI (wt%) 0.12 0.1 0.02 TI (wt%) 7.1 4.78 3.8 Beta resin (wt%) 7.0 4.7 3.8 Ash (wt%) 0.09 0.01 0.01 importance 1.163 1.163 1.160 Viscosity (cP) 75 54 50 refined pitch transference number(%) 32 31 27 QI (wt%) 0.6 0.4 0.12 TI (wt%) 11.2 10.3 12.1 Beta resin (wt%) 10.6 9.8 12.0 Ash (wt%) 0.12 0.07 0.06 importance 1.243 1.242 1.248 Softening Point (℃) 63 62 73

As shown in Table 1, the purified pitch obtained in Example 1 contains 0.03 wt% or less of ash (Ash), and contains 0.1 wt% or less of quinoline insoluble content, but obtained in Comparative Examples 1 to 8 The refined pitch contained more than 0.03 wt% of ash and more than 0.1 wt% of quinoline insoluble content, so it was confirmed that the removal of impurities of heavy tar was not sufficiently performed.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and variations are possible within the scope without departing from the technical spirit of the present invention described in the claims. It will be apparent to those of ordinary skill in the art.

Claims (10)

preparing a heavy tar solution by dissolving heavy tar in an organic solvent;
obtaining a liquid filtrate by solid-liquid separation of the heavy tar solution;
removing the organic solvent from the liquid filtrate;
solid-liquid separation of the filtrate from which the organic solvent has been removed to obtain purified tar; and
distilling the refined tar to prepare a refined pitch;
including,
The organic solvent is THF (Tetra Hydro Furan),
The step of obtaining purified tar by solid-liquid separation of the filtrate from which the organic solvent has been removed is performed in a centrifuge at 1,000 to 2,500 RPM for 40 to 120 seconds,
A method for producing refined pitch from heavy tar.
According to claim 1,
The heavy tar contains 0.2 to 3.0% by weight of ash and 3 to 15% by weight of quinoline insoluble matter (QI) based on the total weight of the heavy tar, and has a viscosity of 1,000 to 4,000 cP and a specific gravity of 1.20 to 1.25 , A method for producing refined pitch from heavy tar.
According to claim 1,
Before adding the organic solvent, the method for producing a refined pitch from heavy tar, further comprising the step of pulverizing the heavy tar.
delete According to claim 1,
The method for producing a refined pitch from heavy tar, wherein the organic solvent is added in an amount of 50 to 100 parts by weight per 100 parts by weight of the heavy tar.
According to claim 1,
The step of obtaining a liquid filtrate by solid-liquid separation of the heavy tar solution is a method for producing purified pitch from heavy tar, which is performed through filtering at a temperature of 30 to 50 °C.
According to claim 1,
The step of removing the organic solvent from the liquid filtrate is a method for producing purified pitch from heavy tar, which is performed by distillation.
delete According to claim 1,
The method for producing refined pitch from heavy tar, wherein the distillation of the refined tar is carried out at a temperature of 300 to 360 °C.
According to claim 1,
The tablet pitch is, based on the total weight of the tablet pitch, ash (Ash) 0.03% by weight or less and quinoline insoluble (QI) 0.1% by weight or less, and a specific gravity of 1.23 or more, a method for producing a refined pitch from heavy tar.