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This post was last edited by jordan569 on 2013-1-6 at 22:38. Coal tar delayed coking technology: I saw quite a lot of discussion on the forum regarding the utilization of coal tar, so I’d like to share my thoughts as well. Based on the current methods of coal tar purification, coal tar mixtures, when used as fuel oil, raw material for carbon black, or anti-corrosion oil without any processing, or after only simple processing, have limited practical value. There is widespread optimism both domestically and internationally regarding the application of its deeply processed and refined products. The traditional coal tar processing technology is usually an organic combination of six basic chemical unit operations, namely distillation, crystallization, extraction, catalytic polymerization, thermal polycondensation, and oxidation. This technology is mature and reliable, but it also has obvious drawbacks: a long production process, complexity in the operations, and high investment costs. With the development of the economy and technology, not only have new uses been found for traditional coal tar processing products, but the coal tar distillate products obtained through the use of new technologies such as hydrocracking and delayed coking are also more competitive in the market. In particular, medium- and low-temperature coal tar contains a high amount of phenols, as well as significant amounts of alkanes and cycloalkanes with relatively low levels of aromatics; it is one of the important sources for synthetic petroleum. Medium and low-temperature coal tar holds great economic value, but it has not been fully utilized in China, instead causing environmental pollution. Therefore, selecting appropriate processes for processing medium- and low-temperature coal tar, and extracting various fuel oil products in high demand from this coal tar, not only enables the comprehensive utilization of resources and increases the added value of the products, but also brings significant economic, environmental, and social benefits. Hydrocracking can carry out hydrorefining of high-temperature coal tar across the entire fraction range, yielding high-quality components for gasoline and diesel blending or as fuel oil; the hydrocracking tail oil can serve as a high-quality feedstock for catalytic cracking or hydrocracking. However, hydrocracking requires harsh operating conditions, the catalysts are expensive, and the capital investment for the plants is high. Delayed coking technology can process various types of heavy residue oils containing asphaltenes, sulfur, and metals, thereby producing the largest amount of distillate products. It has become an important method for converting heavy oils into lighter ones around the world, and it has seen rapid development. It is a mature technology in the petrochemical industry, playing an increasingly important role in the deep processing of heavy oils. Compared with the hydrocracking process, delayed coking features lower capital investment, a simpler process, and mature technology. The products obtained from the delayed coking of coal tar include coker gasoline, coker diesel, coker wax oil, coke, and gases, offering significant economic benefits; it is thus an ideal new process for processing coal tar. There are different types of process flows for delayed coking units. In terms of production scale, there is one furnace with two towers coking and two furnaces with four towers coking. The feedstock first enters the feedstock buffer tank, and then is pumped out using a feedstock pump. It is heated to 340–350°C in the preheating tubes of the convection chamber of the heating furnace, after which it enters the lower part of the distillation tower where it exchanges heat with the high-temperature oil and gas (430–435°C) coming from the top of the coke tower. This process vaporizes the light oils present in the feedstock, while simultaneously heating the feedstock itself to 390–395°C. The raw material, along with the recycled oil, is drawn out from the bottom of the distillation tower and pumped by a hot oil pump into the furnace tubes in the radiant chamber of the heating furnace. There, it is rapidly heated to around 500–550°C, after which it passes through two four-way valves to reach the bottoms of the two coke towers. Hot coal tar undergoes reactions such as cracking and condensation in the coke tower, eventually resulting in the formation of coke. Coke aggregates within the coke tower, while the oil and gas produced by the reaction escape from the top of the coke tower and enter the distillation tower. There, after exchanging heat with the feed oil, they are distilled to yield gas, gasoline, diesel, wax oil, and recycled oil. . Note $ # , $ $