山东益大新材料股份有限公司

精益求精、追求卓越

集土工合成材料生产、销售、设计、施工、服务于一体的土工合成材料综合企业。
/
/
Research and production status of oil-based needle coke

Research and production status of oil-based needle coke

(Summary description)Oil-based needle coke is one of the new carbon materials that are currently receiving high attention. It is an important raw material for the production of graphite electrodes, battery negative electrodes and high-end carbon products. It has a wide and strong industrial demand. In the context of the rapid advancement of a green and ecological society, the graphite electrode industry has embarked on the path of ecological and environmental development, and the demand for oil-based needle coke is increasing.

Research and production status of oil-based needle coke

(Summary description)Oil-based needle coke is one of the new carbon materials that are currently receiving high attention. It is an important raw material for the production of graphite electrodes, battery negative electrodes and high-end carbon products. It has a wide and strong industrial demand. In the context of the rapid advancement of a green and ecological society, the graphite electrode industry has embarked on the path of ecological and environmental development, and the demand for oil-based needle coke is increasing.

Information

Abstract: Oil-based needle coke is one of the new carbon materials that are currently receiving high attention. It is an important raw material for the production of graphite electrodes, battery negative electrodes and high-end carbon products. It has a wide and strong industrial demand. In the context of the rapid advancement of a green and ecological society, the graphite electrode industry has embarked on the path of ecological and environmental development, and the demand for oil-based needle coke is increasing. It has not been long for my country to import oil-based needle coke manufacturing technology from the United States. The research and production of oil-based needle coke still has some gaps in research and production applications compared with advanced countries such as the United States and Europe. This article mainly analyzes the current research and production of oil-based needle coke at home and abroad, and predicts the production trend based on the domestic market, capacity status, and downstream industry demand, and proposes countermeasures and suggestions for optimizing and improving oil-based needle coke production. Oil-based needle coke is a type of needle coke. It is a new type of carbon raw material produced by using heavy oil as the raw material for coking and calcination using a variety of pretreatment processes. The material has a porous solid form with an elliptical pore structure. The material particles have a clear silver appearance and needle-like fiber texture performance. The advantages are high crystallinity, strength and graphitization, low thermal expansion and ablation, and good performance It has good heat resistance, impact resistance and oxidation resistance. It is an important raw material for the production of special carbon materials and ultra-high power electrodes such as graphite electrodes, battery anodes and high-end carbon products. It has a wide and strong industrial demand. Oil-based needle coke was invented by an American company in the 1950s, and it has not been introduced into China for a long time. This article mainly analyzes the current research and production of oil-based needle coke at home and abroad, and predicts the production trend based on the domestic market, capacity status, and downstream industry demand, and proposes countermeasures and suggestions for optimizing and improving oil-based needle coke production.

1 Needle coke overview

1.1 Needle coke

Among modern carbon materials, needle coke is a high-quality material that is unanimously recommended at home and abroad. Needle coke is a variety of artificial graphite. It looks like a silver solid material with metallic luster. The internal structure of the material has large and few oval pores, and it has obvious texture characteristics brought by the flow of needle-like fibers. The needle-shaped coke particles have a lubricating feel to the touch, and the length and width of each particle are relatively large. Needle coke is an important raw material for the production of special carbon materials and ultra-high power electrodes such as graphite electrodes, battery negative electrodes and high-end carbon products. After needle coke was invented in the 1950s, it has become a high-quality type of carbon materials that has been vigorously developed since the 1970s. As a graphitized product, needle coke material has good crystal stability performance, high crystallinity, high strength and graphitization, low thermal expansion coefficient, good heat resistance, good impact resistance and oxidation resistance and other technical advantages, plus The upper material has good mechanical strength performance at low and high temperatures, and is very suitable for applications in the preparation of high-power and ultra-high-power graphite electrodes and special carbon materials. Needle coke is currently the most widely used graphite electrode material in the metallurgical industry. When needle coke is used as a refractory manufacturing material for electric brushes, batteries and other materials for smelting, the smelting time can be reduced by 3-5%, and the power saving effect is about 20%, which has very significant economic benefits.

1.2 Classification of needle coke and performance advantages of oil-based needle coke

The current classification of needle coke is based on different raw materials. In the 1950s, American companies invented oil-based needle coke using heavy oil as a raw material for production. Oil-based needle coke mainly uses heavy distillates processed by thermal cracking of petroleum residues and catalytic cracking of clarified oil as raw materials for needle coke production. The main production technology is represented by American companies, which use delayed coking and calcination processes for product preparation. In the 1970s, Japanese companies invented coal-based needle coke using coal tar and pitch as raw materials. For the pretreatment of raw materials of oil-based needle coke, residue oil, clarified oil, tar, coking wax oil, etc. containing low impurity content are used for processing. Compared with coal-based needle coke, the preparation process can be used in coking Then, a needle coke product with better fiber structure and morphology is obtained. Coal-based needle coke was introduced and produced in China in the 1980s. However, under the background of the country's construction of an ecological and environmentally friendly society, the country has stepped up efforts to control air pollution and rectified the coal tar processing industry. The output of coal tar pitch has fallen sharply, resulting in an increase in the price of coal-based needle coke raw materials and insufficient output of finished products.

1.3 Performance advantages of oil-based needle coke

my country updated the manufacturing standards for oil-based needle coke in 2019, and the national standard code is GB/T37308-2019 oil-based needle coke. Oil-based needle coke is currently classified according to the use of the material. There are mainly needle coke for lithium battery anode materials before forging, needle coke for lithium battery anode materials after forging, and needle coke after forging for graphite electrodes. The advantages of oil-based needle coke are mainly reflected in the fact that the industrial raw materials used to manufacture oil-based needle coke meet the national green and environmental development requirements. At present, the raw materials for industrialized production of oil-based needle coke are mainly catalytic cracking clarified oil, coal tar, naphtha, cracked tar, extracted oil made from lubricating oil solvents, and some petroleum residues. Compared with the coal tar processing industry, it has certain production advantages in the pollution of the atmospheric environment, and it also has a greater advantage in the price of raw materials and the output of needle coke.

2 Research and production status of oil-based needle coke at home and abroad

2.1 Research and production development of foreign oil-based needle coke

The research on oil-based needle coke began in the middle of the last century. The Great Lakes Carbon Company in the United States first invented the oil-based needle coke produced by the delayed coking process in 1950. In the 1960s, the Continental Petroleum Corporation of the United States obtained a technical patent for the industrial production of needle coke, and Standard Oil Corporation put into production the world's first needle coke industrial production plant in Los Angeles. At present, only three countries including the United States, the United Kingdom and Japan have large-scale production capacity of needle coke. Among them, the United States is the country in which oil-based needle coke is invented and the country leading in technology applications. The annual design output of oil-based needle coke in the world currently has a larger lead than coal-based needle coke. It can be said that American companies have monopolized the oil-based needle coke market in the world, and their products account for more than 80% of the world's output. The Houston plant in the United States, the American Carbon/Graphite Group, the British HUMBER Corporation, the Koyo Co., Ltd., and the Mizushima Oil Co., Ltd. are the main producers of oil-based needle coke. As the inventor of the coal-based needle coke, Japan is the world Most of the coal-based needle coke is mainly produced by Nippon Steel Corporation and Mitsubishi Chemical Corporation.

2.2 Research and development of domestic oil-based needle coke

my country began to conduct needle coke research from the 1970s to the 1980s. As the main institute for needle coke research, the Research Institute of Petrochemical Sciences completed the laboratory test of oil-based needle coke in the early 1980s. It has formed a systematic study on the coking principle of oil-based needle coke and found industrial production. The raw materials and coking process and its test methods. Later, the Petrochemical Research Institute carried out industrial production trials of oil-based needle coke in Fushun Petroleum No. 2 Plant and Daqing Petrochemical General Plant. The raw material used was thermal cracking residue, which was produced by delayed coking technology. The oil-based needle coke products produced have made great contributions to the production of ultra-high-power graphite electrodes by domestic manufacturers and steelmaking enterprises. The production of oil-based needle coke is a key technical support project during the national "sixth five-year plan" period.

2.3 The production status of domestic oil-based needle coke

At present, China has become the world’s largest steel producer. Under the adjustment of the national industrial structure, the graphite electrode industry has ushered in a new development opportunity. The proportion of ultra-high power graphite electrode production has increased year by year. The demand is also increasing. my country has become the country with the largest consumption of needle coke in the world and one of the countries with the fastest increase in consumption in the future. Although the country attaches great importance to and supports the production of needle coke, which has led to an explosive growth in production capacity, the demand for high-quality and high-grade needle coke has also continued to grow. The national annual output of needle coke in 2019 was 450,000 tons, a year-on-year increase of more than 25% compared to 2018. The last ten years have been a golden period for the rapid development of domestic needle coke production. At present, the designed annual production capacity of domestic needle coke production equipment has reached more than 600kt.a-1. However, the domestic needle coke production technology level is comparable to that of foreign countries. There is a certain gap. Due to factors such as stricter domestic standards for environmentally-friendly production and the limited production capacity of downstream products such as graphite electrodes, the operating rate of the existing domestic needle coke devices is not high, and the production capacity is difficult to reach the annual design scale. Under the relationship of market supply and demand, the production of domestic oil-based needle coke must seize the good opportunity of increasing market scale, increasing needle coke demand and price, increase production capacity, improve quality, and promote the sustained and sound development of the industry.

3 Problems in the research and production of domestic oil-based needle coke

3.1 Problems in raw material selection and pretreatment

In the industrialized production of needle coke in my country, there are still many problems that need to be properly resolved in order to achieve large-scale and high-quality production. At the stage of raw material selection and pretreatment, liquid carbonization technology is currently used in China for preparation. To improve the effect of raw material pretreatment, it is necessary to prepare raw materials suitable for liquid phase carbonization. The current problems are mainly manifested as follows: First, the needle coke pretreatment process is not very advanced, which causes the coal-based needle coke raw materials to remove the impurities of coal tar pitch. During the pitch refining process, the density, viscosity, softening point and other indicators are at a low level. The unstable state has a direct impact on the quality of subsequent product coking. The second is that the pretreatment effect of quinoline insolubles in coal tar pitch is not good, which causes the content of remaining quinoline insolubles to exceed the standard. The flash method and solvent method used to remove quinoline insolubles in the domestic needle coke industrial production are not adequate, and it is difficult for the existing technology to achieve high-quality pretreatment of coal tar pitch. Third, the domestic petroleum raw materials for needle coke production have relatively high sulfur content, which is not suitable for the production of needle coke; fourth, the catalyst powder carried in the heavy oil produced by petroleum refining is difficult to remove, resulting in a decrease in the quality of needle coke. The main reason for this is that most of the raw materials for the production of oil-based needle coke are heavy petroleum oil, of which the main component is aliphatic hydrocarbons and the content of aromatic hydrocarbons is relatively small. Various catalysts will be used when petroleum is underground for a long time or in the process of mining and processing. As a result, the subsequent production of needle coke raw materials encounters difficulties that are difficult to effectively remove.

3.2 Problems in the coking and calcination stages

In the production process of needle coke, the coking reaction is the most critical link. The raw material of needle coke enters the coking process after pretreatment, and when the temperature rises rapidly, it will enter the coke tower for cracking reaction and condensation reaction. When coking is formed, if pressure treatment is used, the reacted oil can exist as a small molecule liquid, which can effectively reduce the viscosity of the liquid, promote the growth of small mesospheres, and improve the delayed coke performance. This process is called Scorched. In the process of green coke production, it is necessary to precisely control the process indicators such as the temperature, pressure, and cycle ratio of the coke. These process parameters are the core secrets of needle coke manufacturers and will not be announced. The process of studying the industrialized production of oil-based needle coke in my country is not long. In the coking temperature control, there is a certain gap compared with developed countries, which also leads to the unsatisfactory quality of coke production. In the production of needle coke using the heating furnace temperature-variable operation technology, if the operation is not appropriate, the high-temperature oil and gas overflowing from the top of the coke tower will fluctuate greatly, especially if the hot oil and gas pipelines increase sharply during the high-temperature period, it is very easy to cause tower flushing accidents. If the variable temperature operation is incorrect, the amount of hot gas and temperature entering the fractionation tower fluctuates significantly, which will cause a great safety risk in the operation and control of the heating furnace, and may cause accidents such as early coking of the radiant tube and excessively high convection port temperature. In the coke production pressure control, if there are problems with the three indicators of the coke tower's air height, the oil and gas linear velocity, and the foam layer height, it is also easy to cause the coke tower rushing accident.

4 Suggestions on optimization and improvement of domestic oil-based needle coke research and production

4.1 Optimizing raw materials and improving the quality of pretreatment

Raw materials have a direct impact on the quality of needle coke products. To grasp the content index, select the raw materials that help reduce the difficulty of mesophase pitch generation for the follow-up production of needle coke. The first is to increase the content of aromatics in raw materials. The best choice is that the content of short side-chain aromatics can reach about 50%, so that in the subsequent carbonization process, aromatic molecules can form larger planes of aromatic molecules in the condensation reaction to promote the graphite structure The formation of the lattice is more complete. The second is to reduce the content of heptane insoluble matter, and the best index is to control it below 2%. Asphaltenes with molecular polarity and relatively strong reactivity, and low gum content, will not undergo condensation reactions during carbonization to form coke precursors. The third is to control the content of sulfur and nitrogen. The best indicator is that the sulfur content is less than 0.6% and the nitrogen content is less than 1%. The purpose of controlling the sulfur and nitrogen content is to avoid cracks in the electrode due to gas expansion under high temperature. The fourth is to eliminate mechanical impurities such as catalyst powder and control the ash content below 0.05%. This will help control the speed of the carbonization reaction and avoid the problem of the difficulty of producing mesophase spheres due to excessive ash content. Fifth, control the content of heavy metals such as vanadium and nickel within 100 ppm. This can prevent heavy metals from catalyzing, control the nucleation speed of mesophase pellets, allow the pellets to grow sufficiently, and avoid quality problems such as cracks and voids caused by metal impurities. In the pretreatment of raw materials to prepare needle coke, the current mainstream methods are distillation, extraction and hydrogenation. However, under the existing oil refining process, the single use of these three methods will often only achieve a single effect. For example, distillation method can remove undesirable raw material components; extraction method can effectively separate aromatic components from asphaltenes and gums; hydrogenation method can effectively remove impurities such as sulfur and nitrogen. At this time, the above three methods need to be combined and used to better improve the quality of pretreatment.

4.2 Control indicators such as coking and forging temperature

In the process of coking reaction, it is necessary to adopt the method of trial and error to find the best thermal conversion temperature range of the coking reaction according to the generation principle of the mesophase of needle coke, and use the control of total amount, adjustment of flow rate, and reasonable gas injection Measures such as effective control of the coking reaction temperature. To improve the coke yield and increase the density, a proper pressure adjustment method should be adopted to adjust the inlet pressure of the press, so that the gas inside the needle coke can effectively escape before solidification, and promote the better formation of the needle-like structure inside the needle coke. At a suitable coking temperature, the coking process should be extended as much as possible, so as to promote the effective growth and fusion of the mesophase pellets, thereby improving the quality of the finished needle coke. In the forging process, the high-temperature calcination process that isolates air should be used for the characteristics of more moisture and volatile components in the green coke. The calcination process must always keep the green coke at a high temperature of 1500 degrees Celsius. Choose an appropriate calcination method and calcination temperature and time to promote the full reflection of the green coke structure and internal elements, and effectively improve the conductivity and mechanical stability of the needle coke. Mainly learn from the research results of foreign scholars on the quality of needle coke, such as the use of magnetic fieldImprove the microstructure of the coke, use ultrasonic cavitation to improve the internal structure and performance of the needle coke, and add lithium battery materials to penetrate the needle coke structure during calcination, thereby improving the strength and conductivity of the needle coke, and promoting the improvement of the needle coke. The quality of the coke. Domestic enterprises should focus on the production capacity gap of high-quality needle coke products, in-depth study of needle coke production process and operation technology, by optimizing raw materials, improve the quality of pretreatment; control measures such as the temperature of coking and forging, and continuously improve needle coke. The quality of coke production promotes the sustained, healthy and high-quality development of the needle coke industry.

Scan the QR code to read on your phone

全国服务热线:

183-5379-9166

 

Marketing director:+86 183-5379-9166
Human Resources Management:+86 157-5370-6899
Mail:marketing@needlecoke.com
Web:www.sdydxcl.cn

Liangbao Temple Base: North of Hongqi Road, Liangbaosi Town, Jiaxiang County, Shandong Province

Park base: No. 1, Yida Road, Chemical Industry Park, Jiaxiang County, Shandong Province

Copyright © 2022 Shandong Yida New Materials Co., Ltd.   鲁ICP备2021039281号