CN103087745B - A kind of coal tar that utilizes prepares the technique of needle-shape coke raw material in conjunction with heavy phase recycle - Google Patents

Abstract

Utilize coal tar to prepare a technique for needle-shape coke raw material in conjunction with heavy phase recycle, comprising: coal tar fully mixes with the first solvent by (1), the method for employing physical sepn removes the first solvent insolubles in described mixture, obtains the first clear liquor; (2) be separated removing first solvent, hydrogenation carried out to the remaining component after described first solvent of removing, obtains refined asphaltic bitumen; (3) fully mixed with the second solvent by the first solvent insolubles, the method for employing physical sepn removes the second solvent insolubles in described mixture, obtains the second clear liquor; (4) be separated the second solvent in described second clear liquor of removing, obtain refining heavy ingredient; (5) by described refined asphaltic bitumen and described refining heavy ingredient mixing, the raw material for the preparation of needle coke is namely obtained.The needle-shape coke raw material that technique in the present invention prepares has more much higher fragrant fused-ring aromatic content, effectively improves the productive rate of described needle coke product.

Description

A process for preparing needle coke raw materials using coal tar combined with heavy phase circulation

technical field

The invention relates to the field of needle coke preparation, in particular to a process for preparing needle coke raw materials by using coal tar combined with heavy phase circulation.

Background technique

Needle coke is a high-quality material for manufacturing high-power and ultra-high-power electrodes. Graphite electrodes made of needle coke have strong thermal shock resistance, high mechanical strength, good oxidation performance, low electrode consumption and large allowable current density, etc. advantage. The needle coke currently produced can be divided into two categories: petroleum-based needle coke and coal-based needle coke according to the different raw materials used. The Great Lakes Carbon Company of the United States first developed the production process of petroleum-based needle coke in the 1950s. However, due to the trend of petroleum processing towards the direction of catalytic cracking and light-weight deep processing, the raw materials of petroleum-based needle coke have gradually decreased. In addition, the two oil crises in the 1970s made people feel that the supply of raw materials was unstable. Therefore, since the late 1970s At the beginning, the preparation technology of coal-based needle coke has been developed.

Coal-based needle coke is prepared from coal tar. The main component of coal tar is polycyclic aromatic compounds, and it also contains a certain amount of quinoline insolubles (QI). When small spheres are formed, the growth of small spheres will be hindered, making it impossible to form a graphitized structure, which will affect the quality of needle coke. Therefore, when coal tar is used to prepare high-quality needle coke raw materials, the coal tar must be purified to remove quinoline insolubles. Among many purification methods, the solvent method has been widely used because of its simple operation and low cost. application. The solvent method is to mix a suitable solvent with asphalt, and after stirring, standing, and precipitation in the stirring tank, the asphalt is dissolved in the solvent, thereby forming a mixture of asphalt and solvent on the upper layer, and then the mixture is pumped out. Send it to the solvent recovery tower, recover the solvent and produce refined pitch, and finally get the raw material suitable for preparing needle coke. In the prior art, the commonly used solvent is a mixture of aliphatic hydrocarbons and aromatic hydrocarbons in a certain proportion.

For example, Chinese patent document CN101531909A discloses a continuous sedimentation process for the production of needle coke. The process uses coal tar soft pitch as raw material and an organic solvent as an extraction agent to remove quinoline insolubles in the raw material through sedimentation and separation. The obtained light phase is distilled to obtain refined pitch as the raw material for the production of needle coke in the coking unit, and the settled heavy phase is distilled and made into binder pitch for sale. The organic solvent used in the process is a mixture of aliphatic hydrocarbons and aromatic hydrocarbons, wherein the mass ratio of the aliphatic hydrocarbons to aromatic hydrocarbons is 1:0.6-1.4; the initial boiling point of the organic solvent under normal pressure is ≥150°C , Distillation before 310 ° C ≥ 95% (w / w). The refined asphalt with qualified quinoline insoluble content can be obtained through the above process, and has the advantages of less equipment and simple operation.

In fact, the applicant has found through research that, in addition to quinoline insolubles and impurities that hinder the growth of small spheres, the heavy phase that settles down in the above process also contains a large amount of polyaromatic condensation polycyclic aromatic components, and these components It is the basic substance of graphitization to generate needle coke, but in the above process, the settled heavy phase is completely removed, resulting in a low content of polyaromatic condensation and polycyclic aromatic components in the obtained needle coke raw material, so if using The needle coke is prepared from the above raw materials, which in turn leads to a low yield of the needle coke product; and what this process embodies is just the usual technical means in the prior art, that is to say, many years of technological development The technical prejudice that personnel have always existed is to remove the heavy phase containing a large amount of quinoline insolubles and impurities, so that the needle coke raw material contains as little quinoline insolubles as possible that affect the graphitization process. Therefore, so far, there has not been a technology for recycling the heavy phase after treatment in the prior art.

Contents of the invention

In order to solve the problem that the content of polyaromatic condensation and polycyclic aromatic components in the obtained needle coke raw material is low due to the complete removal of the heavy phase components separated in the solvent method in the process of preparing needle coke raw materials in the prior art, And resulting in the problem that the yield of the needle coke product is low when using the above raw materials to prepare needle coke. The invention provides a process for preparing needle coke raw materials by using coal tar combined with heavy phase circulation. The needle coke raw materials prepared by this process have a relatively high content of polyaromatic condensation and polycyclic aromatics, which effectively improves the needle coke Yield of coke products.

The technical scheme of the process for preparing needle coke raw materials by utilizing coal tar combined with heavy phase circulation in the present invention is as follows:

A process for preparing needle coke raw materials from coal tar, comprising:

(1) fully mixing the coal tar with the first solvent, and removing the insoluble matter in the first solvent in the mixture by physical separation to obtain the first clear liquid;

The first solvent is light oil, and the mass ratio of the first solvent to the coal tar is 0.05-10;

(2) separating and removing the first solvent in the first clarified liquid, and hydrogenating the remaining components after removing the first solvent to obtain refined pitch;

(3) fully mixing the first solvent-insoluble matter obtained in step (1) with the second solvent, and removing the second solvent-insoluble matter in the mixture by physical separation to obtain a second clear liquid;

The second solvent is coal-based medium oil, the mass ratio of the coal-based medium oil to the light oil is 1:0.1-1:2, and the second solvent and the insoluble matter in the first solvent The mass ratio is 0.5-50;

(4) separating and removing the second solvent in the second clarified liquid to obtain refined heavy components;

(5) Mixing the refined pitch and the refined heavy components to obtain raw materials for preparing needle coke.

The mass ratio of the first solvent to the coal tar is 0.1-5.

The mass ratio of the first solvent to the coal tar is 0.3-0.7.

The mass ratio of the coal series medium oil to the light oil is 1:0.1-1:1.

The mass ratio of the second solvent to the insoluble matter in the first solvent is 1-10.

The light oil is coal series light oil.

The coal series light oil is one or more of gasoline light oil, BTX, tar light oil and naphtha.

The coal series medium oil is one or more of washing oil, absorbing oil, creosote oil and anthracene oil.

The temperature of the hydrogenation reaction is 300-400° C., and the pressure is 5-20 MPa.

The hydrogenation catalyst is a nickel-molybdenum catalyst.

The temperature of the hydrogenation reaction is 300-350° C., and the pressure is 10-15 MPa.

The physical separation in the step (1) and step (3) is centrifugal separation, and the centrifugal acceleration of the centrifugal separation is 2000-4000G.

The centrifugal acceleration of the centrifugal separation is 2200-3500G.

The process for preparing needle coke raw materials by using coal tar combined with heavy phase circulation in the present invention, step (1) fully mix coal tar and the first solvent, and remove the insoluble matter in the first solvent in the mixture by physical separation , to obtain the first clear liquid; wherein, the first solvent is selected as light oil, and the mass ratio of the first solvent to the coal tar is 0.05-10, preferably 0.1-5, more preferably 0.3-0.7 ; This step is in order to provide the low raw material of quinoline insoluble matter content to hydrogenation reaction, because in hydrogenation reaction, the quinoline insoluble matter in the raw material can cause hydrogenation catalyst deterioration, reduces reaction rate, makes described hydrogenation reaction The yield of the product is reduced, and the economic efficiency is also reduced. Therefore, in order to make the hydrogenation process carry out stably for a long time, it is necessary to remove the quinoline insoluble matter in the asphalt raw material in advance.

Step (2) separating and removing the first solvent in the first clarified liquid, and hydrogenating the remaining components after removing the first solvent to obtain refined pitch; the purpose of removing the light oil solvent is to improve the hydrogenation The treatment efficiency of the reactor. The purpose of hydrotreating the heavy fraction is to increase the hydrocarbon content in the bitumen. During the hydrotreating process, the impurities in the bitumen will be removed, thereby greatly increasing the hydrocarbon content. Effectively prevent the expansion phenomenon of needle coke products.

Step (3) fully mixing the first solvent-insoluble matter obtained in step (1) with the second solvent, and removing the second solvent-insoluble matter in the mixture by physical separation to obtain a second clear liquid; The second solvent is coal-based medium oil, the mass ratio of the coal-based medium oil to the light oil is 1:0.1-1:2, and is preferably set to 1:0.1-1:1; the said The mass ratio of the second solvent to the insoluble matter in the first solvent is 0.5-50, and is preferably set to 1-10. The purpose of this step is to further refine the heavy fraction separated in the solvent method and extract the Polyaromatic condensation of polycyclic aromatic components, thereby abandoning the technical prejudice that those in the art believe that the heavy phase containing a large amount of quinoline insolubles and impurities should be removed. The medium-quality coal-based oil in the present invention refers to oil products with a boiling temperature in the range of 220-350°C.

Steps (4) and (5) separate and remove the second solvent in the second clarified liquid to obtain refined heavy components; then mix the refined pitch and the refined heavy components to obtain polyaromatic condensation poly The needle coke raw material with high content of ring aromatic components can effectively improve the yield of needle coke products.

The advantages of the process for preparing needle coke raw material by using coal tar in combination with heavy phase circulation described in the present invention are:

(1) In the process of preparing needle coke raw materials using coal tar combined with heavy phase circulation described in the present invention, the coal tar pitch is fully mixed with the first solvent, and the first solvent in the mixture is removed by physical separation insoluble matter to obtain the first clear liquid, and after hydrogenation of the first clear liquid, refined pitch is obtained; then the first solvent insoluble matter is fully mixed with coal-based medium oil, and the method of physical separation is used to remove all The insoluble matter in the above mixture is obtained to obtain a second clarified liquid, and the refined heavy fraction is obtained after removing the coal-based medium oil in the second clarified liquid, and finally the refined bitumen is mixed with the refined heavy fraction, that is Raw materials for the preparation of needle coke are obtained. The present invention abandons the technical prejudice that those in the prior art believe that the heavy phase containing a large amount of quinoline insolubles and impurities should be removed, and extracts the first solvent insolubles by using medium oil from coal series to effectively extract the quinoline insolubles Polyaromatic condensed polycyclic aromatic components, using the refined heavy fraction containing a large amount of polyaromatic condensed polycyclic aromatic components to prepare needle coke can effectively increase the yield of the needle coke product.

(2) In the process of preparing needle coke raw materials using coal tar combined with heavy phase circulation in the present invention, the light oil is set as coal-based light oil, and the coal-based light oil is further defined as steam light oil. One or more of oil, BTX, tar light oil, and naphtha. The reason is that the use of these oils is suitable for effectively separating free carbon, solid impurities containing free carbon, and heavy components in coal tar.

(3) In the process of preparing needle coke raw materials using coal tar combined with heavy phase circulation described in the present invention, the physical separation method in steps (1) and (3) is selected as centrifugal separation, and the centrifugal separation The centrifugal acceleration is 2000-4000G. The reason is that the centrifugal separation method has higher separation efficiency than other physical separation methods, such as filtration, sedimentation, etc., and the centrifugal method can effectively remove the quinone in the coal tar raw material. phylloline insolubles. In order to further improve the centrifugal effect, the present invention further limits the centrifugal acceleration to 2200-3500G.

Description of drawings

In order to make the content of the present invention easier to understand, the technical solution of the present invention will be further described below in conjunction with the specific embodiments of the accompanying drawings;

As shown in Fig. 1, it is a schematic diagram of the process for preparing needle coke raw materials by using coal tar combined with heavy phase circulation according to the present invention.

Detailed ways

Example 1

  The process for preparing needle coke raw materials using coal tar combined with heavy phase circulation described in this example includes:

(1) fully mixing the coal tar with the first solvent, and removing the insoluble matter in the first solvent in the mixture by filtering and separating to obtain the first clear liquid;

The first solvent described in this embodiment is petroleum-based naphtha, and the mass ratio of the first solvent to the coal tar is 0.05;

(2) Separating and removing the first solvent in the first clear liquid, hydrogenating the remaining components after removing the first solvent to obtain refined pitch, the temperature of the hydrogenation reaction is 410°C, and the reaction pressure is 22MPa;

(3) fully mixing the first solvent-insoluble matter obtained in step (1) with the second solvent, and removing the second solvent-insoluble matter in the mixture by physical separation to obtain a second clear liquid;

The second solvent selected in this embodiment is a mixture of petroleum-based naphtha and washing oil used as the first solvent, and the mass ratio of the washing oil to the petroleum-based naphtha is 1:2; The mass ratio of the second solvent to the insoluble matter in the first solvent is 0.5;

(4) separating and removing the second solvent in the second clarified liquid to obtain refined heavy components;

(5) Mixing the refined pitch and the refined heavy components to obtain raw materials for preparing needle coke.

Example 2

The process for preparing needle coke raw materials using coal tar combined with heavy phase circulation described in this example includes:

(1) fully mixing the coal tar with the first solvent, and removing the insoluble matter in the first solvent in the mixture by sedimentation and separation to obtain the first clear liquid;

The first solvent described in this embodiment is petroleum-based naphtha, and the mass ratio of the first solvent to the coal tar is 10;

(2) Separating and removing the first solvent in the first clear liquid, hydrogenating the remaining components after removing the first solvent to obtain refined pitch, the temperature of the hydrogenation reaction is 410°C, and the reaction pressure is 22MPa;

(3) fully mixing the first solvent-insoluble matter obtained in step (1) with the second solvent, and removing the second solvent-insoluble matter in the mixture by physical separation to obtain a second clear liquid;

The second solvent selected in this embodiment is a mixture of petroleum naphtha and absorbing oil used as the first solvent, and the mass ratio of absorbing oil to the petroleum naphtha is 1:2; the second solvent The mass ratio of the insoluble matter to the first solvent is 50;

(4) separating and removing the second solvent in the second clarified liquid to obtain refined heavy components;

(5) Mixing the refined pitch and the refined heavy components to obtain raw materials for preparing needle coke.

Example 3

The process for preparing needle coke raw materials using coal tar combined with heavy phase circulation described in this example includes:

(1) fully mixing the coal tar with the first solvent, and removing the insoluble matter in the first solvent in the mixture by sedimentation and separation to obtain the first clear liquid;

The first solvent described in this embodiment is petroleum-based naphtha, and the mass ratio of the first solvent to the coal tar is 0.1;

(2) Separating and removing the first solvent in the first clear liquid, hydrogenating the remaining components after removing the first solvent to obtain refined pitch, the temperature of the hydrogenation reaction is 400°C, and the reaction pressure is 5 MPa;

(3) fully mixing the first solvent-insoluble matter obtained in step (1) with the second solvent, and removing the second solvent-insoluble matter in the mixture by physical separation to obtain a second clear liquid;

The second solvent selected in this embodiment is a mixture of petroleum naphtha and absorbing oil used as the first solvent, and the mass ratio of absorbing oil to the petroleum naphtha is 1:2; the second solvent The mass ratio of the insoluble matter to the first solvent is 10;

(4) separating and removing the second solvent in the second clarified liquid to obtain refined heavy components;

(5) Mixing the refined pitch and the refined heavy components to obtain raw materials for preparing needle coke.

Example 4

The process for preparing needle coke raw materials using coal tar combined with heavy phase circulation described in this example includes:

(1) fully mixing the coal tar with the first solvent, and removing the insoluble matter in the first solvent in the mixture by sedimentation and separation to obtain the first clear liquid;

The first solvent described in this embodiment is petroleum-based naphtha, and the mass ratio of the first solvent to the coal tar is 5;

(2) Separating and removing the first solvent in the first clear liquid, hydrogenating the remaining components after removing the first solvent to obtain refined pitch, the temperature of the hydrogenation reaction is 400°C, and the reaction pressure is 20MPa;

(3) fully mixing the first solvent-insoluble matter obtained in step (1) with the second solvent, and removing the second solvent-insoluble matter in the mixture by physical separation to obtain a second clear liquid;

The second solvent selected in this embodiment is a mixture of petroleum naphtha and absorbing oil used as the first solvent, and the mass ratio of the absorbing oil to the petroleum naphtha is 1:2; The mass ratio of the second solvent to the insoluble matter in the first solvent is 1;

(4) separating and removing the second solvent in the second clarified liquid to obtain refined heavy components;

(5) Mixing the refined pitch and the refined heavy components to obtain raw materials for preparing needle coke.

Example 5

The process for preparing needle coke raw materials using coal tar combined with heavy phase circulation described in this example includes:

(1) fully mixing the coal tar with the first solvent, and removing the insoluble matter in the first solvent in the mixture by sedimentation and separation to obtain the first clear liquid;

In this embodiment, the first solvent is coal-based light oil, the coal-based light oil is gasoline light oil, and the mass ratio of the first solvent to the coal tar is 0.3;

(2) Separating and removing the first solvent in the first clear liquid, hydrogenating the remaining components after removing the first solvent to obtain refined pitch, the temperature of the hydrogenation reaction is 350°C, and the reaction pressure is 10MPa;

(3) fully mixing the first solvent-insoluble matter obtained in step (1) with the second solvent, and removing the second solvent-insoluble matter in the mixture by physical separation to obtain a second clear liquid;

The second solvent selected in this embodiment is a mixture of gasoline and gas oil used as the first solvent and the absorption oil, and the mass ratio of the absorption oil to the gasoline and gas oil is 1:1.5; The mass ratio of the first solvent insoluble matter is 1;

(4) separating and removing the second solvent in the second clarified liquid to obtain refined heavy components; the mass ratio of the second solvent to the insoluble matter in the first solvent is 5;

(5) Mixing the refined pitch and the refined heavy components to obtain raw materials for preparing needle coke.

Example 6

The process for preparing needle coke raw materials using coal tar combined with heavy phase circulation described in this example includes:

(1) fully mixing the coal tar with the first solvent, and removing the insoluble matter in the first solvent in the mixture by sedimentation and separation to obtain the first clear liquid;

In this embodiment, the first solvent is coal-based light oil, the coal-based light oil is BTX, and the mass ratio of the first solvent to the coal tar is 0.7;

(2) Separating and removing the first solvent in the first clear liquid, hydrogenating the remaining components after removing the first solvent to obtain refined pitch, the temperature of the hydrogenation reaction is 320°C, and the reaction pressure is 12 MPa;

(3) fully mixing the first solvent-insoluble matter obtained in step (1) with the second solvent, and removing the second solvent-insoluble matter in the mixture by physical separation to obtain a second clear liquid;

The second solvent selected in this embodiment is a mixture of coal-based gasoline and light oil and absorption oil, and the mass ratio of the absorption oil to the gasoline and light oil is 1:2; the second solvent and the first solvent The mass ratio of insoluble matter is 1;

(4) separating and removing the second solvent in the second clarified liquid to obtain refined heavy components;

(5) Mixing the refined pitch and the refined heavy components to obtain raw materials for preparing needle coke.

Example 7

The process for preparing needle coke raw materials using coal tar combined with heavy phase circulation described in this example includes:

(1) Fully mix the coal tar with the first solvent, remove the insoluble matter in the first solvent in the mixture by centrifugation, and obtain the first clarified liquid, and the centrifugal acceleration of the centrifugation is 2000G;

In this embodiment, the first solvent is coal-based light oil, the coal-based light oil is naphtha, and the mass ratio of the first solvent to the coal tar is 0.5;

(2) Separating and removing the first solvent in the first clear liquid, hydrogenating the remaining components after removing the first solvent to obtain refined pitch, the temperature of the hydrogenation reaction is 300°C, and the reaction pressure is 15MPa;

(3) fully mixing the first solvent-insoluble matter obtained in step (1) with the second solvent, and removing the second solvent-insoluble matter in the mixture by physical separation to obtain a second clear liquid;

The second solvent selected in this embodiment is a mixture of coal tar light oil and anthracene oil, and the mass ratio of the anthracene oil to the tar light oil is 1:0.1; the second solvent and the first solvent The mass ratio of insoluble matter is 10;

(4) separating and removing the second solvent in the second clarified liquid to obtain refined heavy components;

(5) Mixing the refined pitch and the refined heavy components to obtain raw materials for preparing needle coke.

Example 8

The process for preparing needle coke raw materials using coal tar combined with heavy phase circulation described in this example includes:

(1) Fully mix the coal tar with the first solvent, remove the insoluble matter in the first solvent in the mixture by centrifugation, and obtain the first clarified liquid, and the centrifugal acceleration of the centrifugation is 4000G;

In this embodiment, the first solvent is coal-based light oil, the coal-based light oil is gasoline light oil, and the mass ratio of the first solvent to the coal tar is 0.3;

(2) Separating and removing the first solvent in the first clear liquid, hydrogenating the remaining components after removing the first solvent to obtain refined pitch, the temperature of the hydrogenation reaction is 350°C, and the reaction pressure is 15MPa;

(3) fully mixing the first solvent-insoluble matter obtained in step (1) with the second solvent, and removing the second solvent-insoluble matter in the mixture by physical separation to obtain a second clear liquid;

The second solvent selected in this embodiment is a mixture of coal tar light oil and anthracene oil, and the mass ratio of the anthracene oil to the tar light oil is 1:1; the second solvent and the first solvent The mass ratio of insoluble matter is 1;

(4) separating and removing the second solvent in the second clarified liquid to obtain refined heavy components;

(5) Mixing the refined pitch and the refined heavy components to obtain raw materials for preparing needle coke.

Example 9

The process for preparing needle coke raw materials using coal tar combined with heavy phase circulation described in this example includes:

(1) Fully mix the coal tar with the first solvent, remove the insoluble matter in the first solvent in the mixture by centrifugal separation, and obtain the first clear liquid, and the centrifugal acceleration of the centrifugal separation is 2200G;

In this embodiment, the first solvent is coal-based light oil, the coal-based light oil is gasoline light oil, and the mass ratio of the first solvent to the coal tar is 0.7;

(2) Separating and removing the first solvent in the first clear liquid, hydrogenating the remaining components after removing the first solvent to obtain refined pitch, the temperature of the hydrogenation reaction is 330°C, and the reaction pressure is 15MPa;

(3) fully mixing the first solvent-insoluble matter obtained in step (1) with the second solvent, and removing the second solvent-insoluble matter in the mixture by physical separation to obtain a second clear liquid;

The second solvent is a mixture of coal-based tar light oil and creosote oil, and the mass ratio of the creosote oil to the tar light oil is 1:1; the second solvent and the first solvent insoluble The mass ratio of is 1;

(4) separating and removing the second solvent in the second clarified liquid to obtain refined heavy components;

(5) Mixing the refined pitch and the refined heavy components to obtain raw materials for preparing needle coke.

Example 10

The process for preparing needle coke raw materials using coal tar combined with heavy phase circulation described in this example includes:

(1) Fully mix the coal tar with the first solvent, and remove the insoluble matter in the first solvent in the mixture by centrifugation to obtain the first clarified liquid, and the centrifugal acceleration of the centrifugation is 3500G;

In this embodiment, the first solvent is coal-based light oil, the coal-based light oil is gasoline light oil, and the mass ratio of the first solvent to the coal tar is 0.3;

(2) Separating and removing the first solvent in the first clear liquid, hydrogenating the remaining components after removing the first solvent to obtain refined pitch, the temperature of the hydrogenation reaction is 350°C, and the reaction pressure is 10MPa;

(3) fully mixing the first solvent-insoluble matter obtained in step (1) with the second solvent, and removing the second solvent-insoluble matter in the mixture by physical separation to obtain a second clear liquid;

The second solvent is a mixture of coal-based tar light oil and anthracene oil, and the mass ratio of the anthracene oil to the tar light oil is 1:1; the mass ratio of the second solvent to the first solvent-insoluble The ratio is 1;

(4) separating and removing the second solvent in the second clarified liquid to obtain refined heavy components;

(5) Mixing the refined pitch and the refined heavy components to obtain raw materials for preparing needle coke.

In the above examples, as a preferred embodiment, the hydrogenation reaction is carried out in the presence of a nickel-molybdenum-based hydrogenation catalyst, and the nickel-molybdenum-based hydrogenation catalyst is a combination of the active components Ni and Mo Prepared by being supported on a catalyst carrier, the carrier is an Al ₂ O ₃ carrier, and the selection of the catalyst in the present invention is a common prior art in the field, so it will not be repeated in the present invention. In addition, the Ni—Mo-based catalyst described in the present invention is a commercially available product. Of course, as an alternative implementation, other types of hydrogenation catalysts such as _FeS2 can also be selected.

Experimental example

In order to prove that the technical solution of the present invention has substantive technical effects compared with the prior art, the technical effects of the technical solution of the present invention will be further described below in conjunction with specific experimental examples.

Experiment 1: Determination of QI content and hydrocarbon concentration

The QI content of the first clear liquid obtained after removing the first solvent insoluble matter in the above-mentioned embodiment step (1) was measured, and the results showed that the QI content of the first clear liquid in Examples 1-10 was lower than 0.01wt%. The coal tar feedstock used in the above examples had an initial QI concentration of 5.2 wt%.

After measuring the QI content and the concentration of carbon and hydrogen in the raw materials used in the preparation of needle coke obtained in the above examples, the results show that the raw materials used in the preparation of needle coke obtained in Examples 1-10 The QI content in all is lower than 0.01wt%. The concentration of carbon and hydrogen in the raw materials used to prepare needle coke is shown in the table below:

Experiment 2: Determination of thermal expansion coefficient and yield of needle coke

During the experiment, the raw materials for preparing needle coke obtained in the above examples were put into a coking device for preparing needle coke, and coked at 550° C. for 5 hours to obtain needle coke.

The needle coke product is graphitized at 1300°C, and the coefficient of thermal expansion of the graphitized needle coke is shown in the following table:

Further, the needle coke yield when the above-mentioned raw material is prepared from the needle coke is measured, and the results are shown in the following table:

comparative example

In order to further illustrate that the technical solution described in the present invention has substantive technical effects compared with the prior art, the present invention provides the following comparative examples:

(1) Using the same coal tar raw material as in the examples, fully mixing the coal tar with the solvent, and removing the solvent-insoluble matter in the mixture by filtration to obtain a clear liquid;

Solvent described in this comparative example is the mixture of aliphatic hydrocarbon and aromatic hydrocarbon, and the mass ratio of described aliphatic hydrocarbon and aromatic hydrocarbon is 1: 1; The initial boiling point of described solvent is about 160 ℃ under normal pressure, and described mixture is in Distillation before 310°C is 97% (w/w)

(2) Separating and removing the solvent in the clarified liquid to obtain raw materials for preparing needle coke.

The raw materials for preparing needle coke obtained in this comparative example were put into a coking device for preparing needle coke, and coked at 550° C. for 5 hours to obtain needle coke.

The needle coke product is graphitized at 1300°C, and the thermal expansion coefficient of the graphitized needle coke is 1.5×10 ^-6 /°C.

Further, the yield of needle coke when the needle coke was prepared from the raw materials obtained in this comparative example was measured, and the yield of needle coke was 35%.

From the above comparison, it can be seen that the thermal expansion coefficient of the needle coke in the comparative example is increased by 0.4-0.8×10 ^-6 /°C compared with the example, which is enough to reduce the quality of the graphite electrode prepared by the needle coke in actual use. Great influence; In addition, the productive rate of needle coke in the comparative example reduces 12-18% compared to embodiment, it can be seen that the technical scheme among the present invention can obviously improve the productive rate of needle coke product, therefore, among the present invention Compared with the prior art, the technical solution has obvious substantive technical effects.

Although the present invention has been described in detail through specific implementation methods, those skilled in the art should understand that any changes in form and details made on this basis that do not exceed the scope of protection of the claims belong to the present invention. The scope of the invention to be protected.

Claims (17)

1. A process for preparing needle coke raw materials utilizing coal tar combined with heavy phase circulation, comprising: (1) Fully mixing the coal tar with the first solvent, removing the first solvent-insoluble matter in the mixture by physical separation to obtain the first clear liquid; The first solvent is coal-based light oil, and the mass ratio of the first solvent to the coal tar is 0.05-10; (2) separating and removing the first solvent in the first clarified liquid, and hydrogenating the remaining components after removing the first solvent to obtain refined pitch; (3) fully mixing the first solvent-insoluble matter obtained in step (1) with the second solvent, and removing the second solvent-insoluble matter in the mixture by physical separation to obtain a second clear liquid; The second solvent is coal-based medium oil, the mass ratio of the coal-based medium oil to the coal-based light oil is 1:0.1-1:2, and the second solvent and the first solvent The mass ratio of insoluble matter is 0.5-50; (4) separating and removing the second solvent in the second clarified liquid to obtain refined heavy components; (5) Mixing the refined pitch and the refined heavy components to obtain raw materials for preparing needle coke. 2. The process for preparing needle coke raw material by using coal tar combined with heavy phase circulation according to claim 1, characterized in that the mass ratio of the first solvent to the coal tar is 0.1-5. 3. The process for preparing needle coke raw material by using coal tar combined with heavy phase circulation according to claim 2, characterized in that the mass ratio of the first solvent to the coal tar is 0.3-0.7. 4. The process for preparing needle coke raw materials by utilizing coal tar combined with heavy phase circulation according to claim 1, 2 or 3, characterized in that the mass ratio of the coal-measure medium oil to the coal-measure light oil 1:0.1-1:1. 5. The process for preparing needle coke raw materials by using coal tar combined with heavy phase circulation according to claim 1, 2 or 3, wherein the mass ratio of the second solvent to the first solvent insoluble matter is 1 -10. 6 . The process for preparing needle coke raw materials by using coal tar combined with heavy phase circulation according to claim 4 , wherein the mass ratio of the second solvent to the first solvent insoluble is 1-10. 7. The process for preparing needle coke raw materials using coal tar combined with heavy phase circulation according to claim 1, 2, 3 or 6, wherein the coal series light oil is gasoline light oil, BTX, tar light oil One or more of oil and naphtha. 8. The process for preparing needle coke raw materials using coal tar combined with heavy phase circulation according to claim 1, 2, 3 or 6, wherein the medium oil in the coal series is washing oil, absorbing oil, creosote One or more of oil and anthracene oil. 9. The process for preparing needle coke raw materials by using coal tar combined with heavy phase circulation according to claim 1, 2, 3 or 6, characterized in that the temperature of the hydrogenation reaction is 300-400°C, and the pressure is 5 -20MPa. 10. The process for preparing needle coke raw materials by using coal tar combined with heavy phase circulation according to claim 4, characterized in that the temperature of the hydrogenation reaction is 300-400° C., and the pressure is 5-20 MPa. 11. The process for preparing needle coke raw material by using coal tar combined with heavy phase circulation according to claim 5, characterized in that the temperature of the hydrogenation reaction is 300-400° C., and the pressure is 5-20 MPa. 12. The process for preparing needle coke raw material by using coal tar combined with heavy phase circulation according to claim 7, characterized in that the temperature of the hydrogenation reaction is 300-400° C., and the pressure is 5-20 MPa. 13. The process for preparing needle coke raw material by using coal tar combined with heavy phase circulation according to claim 8, characterized in that, the temperature of the hydrogenation reaction is 300-400° C., and the pressure is 5-20 MPa. 14. The process for preparing needle coke raw materials using coal tar combined with heavy phase circulation according to any one of claims 1, 2, 3, 6, 10-13, characterized in that the hydrogenation catalyst is a nickel-molybdenum catalyst. 15. According to any one of claims 1, 2, 3, 6, 10-13, the process for preparing needle coke raw materials by using coal tar combined with heavy phase circulation, is characterized in that the temperature of the hydrogenation reaction is 300 -350°C, the pressure is 10-15MPa. 16. The process for preparing needle coke raw materials using coal tar combined with heavy phase circulation according to any one of claims 1, 2, 3, 6, 10-13, characterized in that the steps (1) and The physical separation in (3) is centrifugal separation, and the centrifugal acceleration of the centrifugal separation is 2000-4000G. 17. The process for preparing needle coke raw material by using coal tar combined with heavy phase circulation according to claim 16, characterized in that the centrifugal acceleration of the centrifugal separation is 2200-3500G.