uhp 500 graphite electrodes
Needle coke and uhp 500 graphite electrodes
The production process of carbon materials is a strictly controlled system engineering. The production of uhp 500 graphite electrodes, special carbon materials, carbon for aluminum, new high-end carbon materials, etc. are inseparable from raw materials, equipment, technology, management, and 4 production elements and related The combined use of proprietary technologies.
The raw material is the key element that determines the basic characteristics of the carbon material, and the performance of the raw material determines the performance of the manufactured carbon material. For the production of UHP and HPuhp 500 graphite electrodes, high-quality needle coke is the first choice, as well as high-quality binder pitch and impregnant pitch. But only high-quality raw materials, lack of equipment, technology, management elements and related proprietary technology, it is also impossible to produce high-quality UHP, HPuhp 500 graphite electrodes. This article focuses on explaining some personal views on some characteristics of high-quality needle coke for discussion and discussion with colleagues from needle coke manufacturers, uhp 500 graphite electrodes manufacturers, and research institutes. Although the industrialized production of needle coke in my country is later than that of foreign companies, it has developed rapidly in recent years and has begun to take shape. In terms of total production, it can basically meet the needs of domestic carbon companies to produce UHP and HPuhp 500 graphite electrodes for needle coke. Quantity demand.
However, there is still a certain gap in the quality of needle coke compared with foreign companies. The fluctuation of batch performance affects the demand for high-quality needle coke in the production of large-size UHP and HPuhp 500 graphite electrodes, especially the uhp 500 has not yet been able to meet the demand. The high-quality needle coke used in the production of graphite electrodes. Foreign carbon companies producing large-size UHP and HPuhp 500 graphite electrodes often prefer high-quality petroleum needle coke as the main raw material coke. Japanese carbon companies also use some coal-based needle coke as raw materials, but they are only used for uhp 500 graphite electrodes with specifications below Φ600 mm. Production. my country’s needle coke is currently mainly coal-based needle coke. The production of high-quality large-size UHPuhp 500 graphite electrodes by various carbon companies often relies on imported petroleum-based needle coke, especially the production of high-quality joints imported from Japan’s Mizushima Oil-based needle coke and British HSP oil-based needle coke are used as raw materials. At present, the needle coke produced by various enterprises is usually compared with the commercial performance indicators of foreign needle coke by conventional performance indicators, such as ash content, true density, sulfur content, nitrogen content, particle size distribution, and thermal expansion coefficient. However, compared with foreign countries, there is still a lack of needle coke classification with different levels of performance in the needle coke classification. Therefore, most of the needle coke produced is generally “all goods”, which does not reflect the quality and price of needle coke in different grades. In the comparison of needle coke performance, in addition to the conventional performance comparison, carbon companies should also pay attention to the classification of needle coke’s coefficient of thermal expansion (CTE), particle strength, anisotropy, non-inhibited state and expansion data in inhibited state The characteristics of needle coke, such as the temperature range during expansion and contraction.
Because these thermal properties of needle coke are very important for the control of the graphitization process in the production of uhp 500 graphite electrodes, of course, the influence of the thermal properties of the pitch coke formed after the firing of the binder and impregnant pitch is not ruled out.
1. Comparison of anisotropy of needle coke
(A) Sample: Φ500 mm UHPuhp 500 graphite electrodes from a domestic carbon factory; raw needle coke: Japan’s new daily chemical LPC-U grade, ratio: 100% LPC-U grade; analysis: SGL Griesheim factory; see performance indicators Table 1.
(B) Sample: Φ450 mmHPuhp 500 graphite electrodes from a domestic carbon factory; raw needle coke: petroleum needle coke from a domestic factory, ratio: 100%; analysis: Shandong Bayan Carbon Factory; performance indicators are shown in Table 2. It can be seen from the comparison of Table 1 and Table 2 that the thermal performance anisotropy of the LPC-U grade of Xinrihua coal series needle coke is relatively large, and the CTE anisotropy can reach 3.61~4.55, and the resistivity is anisotropy. The degree of anisotropy is also relatively large, reaching 2.06~2.25. The domestic petroleum needle coke is far lower in the evaluation of anisotropy than the new one, except that the flexural strength of the domestic petroleum needle coke is better than that of the new daily chemical LPC-U level coal needle coke. Daily chemical LPC-U coal series needle coke. The anisotropy performance analysis of the finished product of ultra-high power uhp 500 graphite electrodes is a very important analysis method to evaluate the quality of the raw needle coke. Of course, the anisotropy is also important to the production process of uhp 500 graphite electrodes. The process has a certain influence. The thermal shock resistance of uhp 500 graphite electrodes with high anisotropy is much better than that of ordinary power uhp 500 graphite electrodes with low anisotropy. The current domestic coal-based needle coke production volume is far greater than the petroleum needle coke production volume. Due to the current dilemma of high raw material cost and price factors faced by various carbon companies, it is difficult to use 100% domestic production in the production of UHPuhp 500 graphite electrodes. Needle coke is produced, and a certain proportion of calcined petroleum coke and graphite chips are mixed to produce uhp 500 graphite electrodes, so it is difficult to evaluate the anisotropy performance of domestic needle coke.
2. The linearity and volume change performance of needle coke.
The linearity and volume change performance of needle coke is mainly reflected in the graphitization process produced by uhp 500 graphite electrodes. As the temperature changes, the needle coke is heated during the graphitization process. The linear and volumetric expansion and contraction changes will directly affect the linear and volumetric changes of the uhp 500 graphite electrodes baked blanks in the graphitization production. This is what happens to the coke with different properties and different grades of needle coke. Changes are not the same. Moreover, the linearity and volume change of different grades of needle coke and calcined petroleum coke have different temperature ranges. Only by mastering this characteristic of raw coke can we better control and optimize the production of graphitization process. This is particularly evident in the production process of tandem graphitization. Table 3 shows the linearity and volume changes and temperature ranges of the three grades of petroleum needle coke produced by ConocoPhillips’ UK plant. When the oil-based needle coke starts to heat up, linear expansion occurs first, but the temperature at which the linear shrinkage begins often lags behind the maximum calcination temperature. 200°C. However, the temperature range of ordinary delayed petroleum coke’s entire linear shrinkage is much larger than that of needle coke. Coal-based needle coke is somewhere in between, and slightly larger than oil-based needle coke. The test results of the Osaka Institute of Industrial Technology Test Institute in Japan show that the worse the thermal performance of the coke, the larger the linear shrinkage temperature range, which can reach the linear shrinkage temperature range of 500 to 600 ℃, and the starting temperature of the linear shrinkage is low. Linear shrinkage begins at 1150～1200℃, which is also the characteristic of ordinary delayed petroleum coke. The better the thermal performance of needle coke and the greater the degree of anisotropy, the narrower the temperature range of linear shrinkage. Some high-quality oil-based needle coke only has a linear shrinkage temperature range of 100-150°C. After understanding the characteristic changes of various raw material coke, such as expansion, contraction and expansion after heating, it is very useful for carbon companies to guide graphitization process production, and it can avoid some unnecessary quality waste products caused by the traditional empirical power transmission mode. .
Master the various characteristics of the raw materials, select reasonable equipment matching, good process technology combination, and the enterprise’s management is becoming more scientific and reasonable. This series of whole processes are systematically controlled and stable, and it can be said to have It is the basis for the production of high-quality ultra-high-power, high-power uhp 500 graphite electrodes.