Newbie seeking help: production of pitch coke and coal tar pitch
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Dear seniors, I’m not from the oil or coal industry, so I don’t know much about these things. The question is a bit naive; I hope everyone will kindly offer their guidance. First question: Dear seniors, regarding the formation of coal tar pitch coke, the material particles are calcined under a protective atmosphere so that they no longer stick together (it seems that a certain temperature treatment has been applied). It has a high volatile content (15%-50% by mass), a low ash content (less than 0.2% by mass), and a very low sulfur content; it is said to be less than 0.02%, but this hasn’t been confirmed through testing. It can be converted into graphite after reaching the graphitization temperature. What kind of coking is this? What kind of companies are there in the country that produce this? A friend said that there are companies in the north that produce this kind of product; I hope the seniors here can help give some advice to the juniors. Second question: Dear seniors, is petroleum asphalt or coal tar pitch isotropic? And what about the quinoline-insoluble content – should it be less than 2.5% (it seems the lower, the better)? There seem to be requirements as well regarding those toluene-insoluble substances, but I still haven’t understood what they are or what effect they have on asphalt. Lastly, the softening point should be as high as possible; 240 degrees or higher would be ideal. The coking value should also be high, while the ash content and sulfur content should be very low. I wonder if the seniors here have any resources in this area that could help the juniors?
Is this question too difficult? Still not hitting the mark? Is it really impossible for anyone to answer?
Reply to 1# troubleltj: Is the first question somewhat similar to calcined coke in petroleum coke? In the past, the coking plant of Wuhan Iron and Steel Corporation produced pitch coke by feeding liquid pitch into a pitch coke furnace for coking. The second issue is that the toluene-insoluble substances are the same as the quinoline-insoluble substances. Due to the complex composition of coal tar pitch, it is generally not necessary to determine the exact amount of each component present. Instead, solvents such as toluene (benzene) and quinoline are used, based on the molecular weights of the different substances in the pitch, to determine the proportions of these substances with varying molecular weights, thereby enabling the analysis of coal tar pitch. (Previously, benzene and pyridine were used as solvents, but they were replaced by toluene and quinoline due to their toxicity and strong odor.) The insoluble portion after extraction with toluene is called toluene-insoluble matter (TI), while the soluble portion is called toluene-soluble matter (TS) ； The portion that remains insoluble after extracting the toluene-insoluble material with quinoline is called quinoline-insoluble material (QI), while the soluble portion is referred to as toluene-insoluble/quinoline-soluble material (TI-QS). QI are macromolecular substances present in coal tar pitch, such as coal powder, coke powder, and highly polymerized polycyclic aromatic hydrocarbons; these substances have high ash content, high electrical resistivity, difficulty in graphitization, and high coking value ； TI-QS are medium-molecular-weight substances in coal tar pitch; they have good adhesiveness, are easy to graphitize, and exhibit a favorable coking value ； TS is the substance with the lowest molecular weight in coal tar pitch, and it is mainly volatile matter as well. If pitch coke is to be used as a carbon material, it is required to have low ash, volatile matter, and sulfur content, as well as a high coking value. Since ash has a significant impact on the electrical resistance of carbon materials, high volatile content and low coking value result in higher porosity and lower true density of these materials after calcination and graphitization, thereby reducing their strength. Sulfur, on the other hand, tends to cause \"bloating\" during the calcination process, leading to cracking of the products and an increase in waste. I’m not sure if the above content is helpful to you.
Reply to 3# meself Thanks! A few key points are now basically clear; next is to find out where such suitable products can be found This is also the most important. I hope some seniors can give me some advice? Which domestic manufacturers are currently selling this material? I talked with a moderator from the petroleum sector yesterday, and the general direction seems clear: it’s likely that there will be delays in the development of needle coke. But so far, no manufacturer that sells it has been found.