Method for processing full-range oil in coal tar

Abstract

The invention relates to the field of coal chemical industry and discloses a method for processing full-range oil in coal tar; the method comprises: introducing full-range oil of coal tar, hydrogen and hydrogenation catalyst I into a primary slurry-bed reactor for hydrocracking reaction; separating cracked mixture; introducing hydrogen, hydrogenation catalyst II and the obtained heavy oil into a secondary slurry-bed reactor with external cyclone hydraulic separator to carry out mild hydro-conversion reaction, introducing the reacted material obtained through the mild hydro-conversion reaction into the cyclone hydraulic separator for separating; circulating the obtained high-concentration phase back to the secondary slurry-bed reactor, and introducing light oil and low-density phase into a fixed-bed hydrogenation apparatus for hydrogenation reaction. By processing the full-range oil of coal tar through the method of the invention, it is possible to maximally produce clean fuels. The method of the invention may also prevent the problems of the prior art, such as high energy consumption, short operation cycle, and unreasonable diesel-gasoline ratio.

Description

technical field [0001] The invention relates to the field of coal chemical industry, in particular to a method for processing whole distillate oil of coal tar. Background technique [0002] Coal tar is a black or dark brown, viscous liquid product with a pungent odor produced by coal in the dry distillation and gasification process. According to the process reaction temperature, it can be divided into low-temperature coal tar (450-650°C), medium-temperature coal tar (600-1000°C) and high-temperature coal tar (greater than 1000°C). Overall, the annual output of coal tar in my country has exceeded 20 million tons. In 2011, the total production capacity of high-temperature coal tar in my country was about 22 million tons, and the actual output was about 17.5 million tons; the total production capacity of medium-low temperature coal tar was about 6 million tons, and the total output reached 3.5 million tons. In addition, a large number of coal-to-natural gas installations in m...

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Problems solved by technology

However, this existing technology requires complex pretreatment of the whole fraction of coal tar, and it is difficult to ensure long-term operation when the material recycled to the slurry bed reaction unit is filtered.

[0005] Specifically, the prior art mainly has the following problems: first, the raw material of coal tar has high viscosity, wherein water or solid particles and coal tar etc. wrap each other, so it is difficult to separate and purify, and the separated water contains a large amount of phenol, polyphenols, etc. Pollutants such as cycloaromatic hydrocarbons are highly toxic and difficult to treat and purify; secondly, if the coal tar raw material is cut by distillation, the energy consumption of the whole plant will be increased, and after the heavy fraction enters the slurry bed reactor, the coke-prone components are in the The increase of the content in the reactor will not only affect the operation cycle of the device, but also be detrimental to prolonging the service life of the catalyst; third, the overall conversion rate of the slurry bed reaction process is not high, which affects the reaction severity of the subsequent fixed bed refining section, which in turn leads to the final The diesel fraction content in the product is too high, and the diesel-gasoline ratio of the process is unreasonable, which affects the economy of the overall process

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