A method for producing needle coke for electrode tips

Abstract

The present application relates to the technical field of needle coke, in particular to a production method of needle coke for electrode joint. The production method takes ethylene tar 450-490 DEG C fraction and catalytic oil slurry 420-510 DEG C fraction as coking raw materials, sends the coking raw materials into a coke tower through a low-temperature heating furnace, adds coking wax oil into the coke tower through a high-temperature heating furnace, produces needle coke coking through cracking and polycondensation reaction, and obtains needle coke for electrode joint after calcination. The present application increases the source of raw materials, shortens the reaction time, improves the quality and yield of needle coke, and can meet the use needs of electrode joint.

Description

Technical Field

[0001] This invention relates to the field of needle coke technology, and more specifically to a method for producing needle coke for electrode connectors. Background Technology

[0002] Needle coke is a high-quality variety of carbon materials that is being vigorously developed. It is a porous solid with a silvery-gray appearance and a metallic luster. The pores are large and few and slightly elliptical. The particles have a large length-to-width ratio and the structure has obvious flow texture, with a fibrous or needle-like texture. It feels smooth to the touch.

[0003] Current needle coke production processes generally include three stages: raw material pretreatment, delayed coking, and calcination. Depending on the raw material, needle coke can be divided into oil-based needle coke and coal-based needle coke. Needle coke produced from coal tar pitch and its fractions is called coal-based needle coke, while needle coke produced from petroleum residue is called oil-based needle coke. The main process for oil-based needle coke involves cracking and condensing the feedstock oil in a coking tower, followed by calcination to produce qualified needle coke for use as a connector. However, due to the instability of the feedstock oil, the quality of currently produced oil-based needle coke is also unstable, with issues such as high sulfur content and substandard particle strength coefficients, seriously affecting the subsequent use of the needle coke.

[0004] High-quality graphite electrode joints generally use oil-based needle coke as raw material. The true density, ash content, sulfur content, coefficient of thermal expansion (CTE), and Hastelloy abrasion index of needle coke are very important for controlling the graphitization process in the production of electrode joints.

[0005] Therefore, it is necessary to provide a method for producing needle coke for electrode connectors. Summary of the Invention

[0006] To address the technical problem that existing processes produce needle coke with high sulfur content and performance that fails to meet the requirements of electrode connectors, this invention provides a method for producing needle coke for electrode connectors. This method increases the source of raw materials, shortens the reaction time, and improves the quality and yield of needle coke, thus meeting the needs of electrode connectors.

[0007] The technical solution of this invention is as follows:

[0008] A method for producing needle coke for electrode connectors involves using ethylene tar fraction at 450-490℃ and catalytic oil slurry fraction at 420-510℃ as coking raw materials. The coking raw materials are fed into a coking tower through a low-temperature heating furnace, and coking wax oil is added to the coking tower through a high-temperature heating furnace. Through cracking and polycondensation reactions, needle coke raw coke is produced, and after calcination, needle coke for electrode connectors is obtained.

[0009] Furthermore, it is preferable to use the 460-480℃ fraction of ethylene tar and the 450-480℃ fraction of catalytic oil slurry.

[0010] Furthermore, the mass of the ethylene tar 450-490℃ fraction accounts for 10%-40% of the mass of the coking feedstock, preferably 30%.

[0011] Furthermore, the coking raw material is heated to 430-470℃ in a low-temperature heating furnace to ensure the growth of mesophase microspheres, preferably 460℃.

[0012] Furthermore, the coking wax oil is heated to 500-520℃, preferably 515℃, using a high-temperature heating furnace.

[0013] Furthermore, the amount of coking wax oil added accounts for 10%-30% of the mass of the coking raw materials, preferably 20%.

[0014] Furthermore, the reaction pressure of the coking tower is 0.5-0.7 MPa, preferably 0.6 MPa.

[0015] Furthermore, the calcination temperature is 1450-1550℃.

[0016] The beneficial effects of this invention are as follows:

[0017] The method for producing needle coke for electrode connectors provided by the present invention uses ethylene tar at 450-490℃ and catalytic oil slurry at 420-510℃ as coking raw materials, which expands the raw material sources of needle coke, shortens the reaction time, and improves the quality and yield of needle coke. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0019] Example 1

[0020] The coking feedstock is a mixture of ethylene tar fraction at 460-480℃ and catalytic oil slurry fraction at 450-480℃, with a mass ratio of 3:7. The feedstock is fed into the coke tower through a low-temperature heating furnace for 36 hours, with the temperature maintained at 460℃ to ensure the growth of mesophase microspheres.

[0021] Coking wax oil heated to 515℃ is added to the coke tower in a high-temperature heating furnace at a rate of 20wt% of the coking raw material. The process takes about 5 hours, and the high temperature is maintained for 6 hours. The reaction pressure is controlled at 0.6MPa to induce cracking and condensation reactions, producing needle coke raw coke. After calcination at 1450℃, needle coke for electrode connectors is obtained.

[0022] Example 2

[0023] The coking feedstock is a mixture of ethylene tar fraction at 450-490℃ and catalytic oil slurry fraction at 420-510℃, with a mass ratio of 2:8. The feedstock is fed into the coke tower through a low-temperature heating furnace for 32 hours, with the temperature maintained at 450℃ to ensure the growth of mesophase microspheres.

[0024] Coking wax oil heated to 505°C is added to the coke tower in a high-temperature heating furnace at a rate of 10 wt% of the coking raw material. The process takes about 4 hours, and the high temperature is maintained for 6 hours. The reaction pressure is controlled at 0.7 MPa to induce cracking and condensation reactions, producing needle coke raw coke. After calcination at 1500°C, needle coke for electrode connectors is obtained.

[0025] Example 3

[0026] The coking feedstock is a mixture of ethylene tar fraction at 460-480℃ and catalytic oil slurry fraction at 450-480℃, with a mass ratio of 4:6. The feedstock is fed into the coking tower through a low-temperature heating furnace for 40 hours, with the temperature maintained at 480℃ to ensure the growth of mesophase microspheres.

[0027] Coking wax oil heated to 520°C is added to the coke tower in a high-temperature heating furnace at a rate of 30 wt% of the coking raw material. The process takes about 7 hours, and the high temperature is maintained for 8 hours. The reaction pressure is controlled at 0.5 MPa to induce cracking and condensation reactions, producing needle coke raw coke. After calcination at 1550°C, needle coke for electrode connectors is obtained.

[0028] Comparative Example 1

[0029] The catalytic oil slurry was used alone at 450-480℃ as a coking feedstock, and the remaining processes and conditions were the same as in Example 1.

[0030] The needle coke produced in Example 1 and Comparative Example 1 was tested, and the test results are shown in Table 1 below.

[0031] Table 1. Test results of coking performance of needle coke

[0032]

[0033] As can be seen from Table 1, adding ethylene tar fraction is beneficial to improving the quality of coke and reducing the sulfur content.

[0034] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. A method for producing needle coke for electrode connectors, characterized in that, Using ethylene tar fraction (450-490℃) and catalytic oil slurry fraction (420-510℃) as coking feedstock, the coking feedstock is heated to 430-470℃ in a low-temperature heater and then fed into a coking tower. Coking wax oil is heated to 500-520℃ in a high-temperature heater and then added to the coking tower. Through cracking and polycondensation reactions, needle coke is produced, which, after calcination, yields needle coke for electrode connectors. The mass of the ethylene tar fraction (450-490℃) accounts for 10%-40% of the mass of the coking feedstock. The reaction pressure in the coking tower is 0.5-0.7 MPa. The amount of coking wax oil added accounts for 10%-30% of the mass of coking raw materials.

2. The production method as described in claim 1, characterized in that, The coking feedstock consists of ethylene tar fraction at 460-480℃ and catalytic oil slurry fraction at 450-480℃.

3. The production method as described in claim 1, characterized in that, The calcination temperature is 1450-1550℃.

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