Method for removing dicyclopentadiene from ethylene cracked carbon 9 fraction

Abstract

The invention provides a method for removing dicyclopentadiene from ethylene cracked carbon 9 fraction. The method includes: adding a selective solvent to the ethylene cracked carbon 9 fraction to carry out distillation under reduced pressure, selectively separating the dicyclopentadiene from the carbon 9 fraction extremely complex in component, approximate in boiling point and difficult to separate with common distillation methods, further treating the removed dicyclopentadiene containing the selective solvent, and then recycling the separated selective solvent to obtain the high-purity dicyclopentadiene. The selective solvent is utilized to highly selectively separate the dicyclopentadiene, content of the dicyclopentadiene in the carbon 9 fraction can be lowered to below 1%, and the influence of the residual of the dicyclopentadiene on the quality of the subsequent petroleum resin is removed; the problem that active components in the high temperature cracking method are prone to implosion resulting in blockage to equipment is avoided, potential risks brought by frequent cleaning are completely eradicated, production cost is lowered, and long-cycle, continuous and stable production is realized.

Description

technical field [0001] The invention belongs to the technical field of chemical separation, and in particular relates to a method for removing dicyclopentadiene from ethylene cracking carbon nine fractions. Background technique [0002] The C9 aromatics fraction (referred to as cracked C9) produced by the ethylene plant is the remaining fraction after separating the C5 fraction and the C6-C8 fraction (by hydrogenation to produce BTX) from pyrolysis gasoline, accounting for 10% to 20% of the total ethylene production. %, for the C9 and C9+ components of ethylene by-products, its most important feature is that it is rich in diolefins and vinyl aromatics, and has high reactivity. In addition to producing solvent oil, extracting heavy aromatics components and increasing the production of light aromatics, currently The most important way is to produce C9 petroleum resin, which is widely used in chemical industries such as paints, inks, coatings, and adhesives, and is an important...

AI Technical Summary

Problems solved by technology

[0004] Among them, the third type of components in the C9 fraction of ethylene cracking, especially dicyclopentadiene (DCPD) has a high activity and is the main factor affecting the hue of the resin. Foreign countries have strict requirements on it, and the general requirement is not more than 2%. The DCPD content in the C9 fraction is relatively high, generally as high as 15%, which leads to the fact that there are not many C9 petroleum resin grades in my country, the color is darker, and there is no uniform quality index. The application is not yet widespread. At the same time, it affects the application in high-grade paint. There are also some applications in additives, low-grade inks, and adhesives in rubber shoe factories

[0005] The boiling point of DPCD and methyl styrene, which affects the quality of C9 petroleum resin, is only 0.6 degrees, and the composition of the cracked C9 fraction is extremely complex, and the boiling point is very close. It is impossible to remove DCPD by ordinary distillation. Therefore, the existing production methods and published The patent adopts the cracking chemical method of liquid-phase depolymerization or gas-phase depolymerization. The C9 fraction is heated to 200-380 degrees through a heating furnace, and the dicyclopentadiene in the C9 fraction is depolymerized, and then rectified by a rectification tower. Mixed diene monomers are obtained at the top, and pyrolysis gasoline fractions are obtained at the bottom of the tower; however, due to the reversibility of dicyclopentadiene depolymerization and polymerization, the dicyclopentadiene remaining in the carbon nine fraction by the cracking method is generally about 3-5%. It is extremely difficult to reach a level below 1%. In addition, regardless of the cracking method, a high temperature above 200°C must be used, which will cause a large amount of dicyclopentadiene to polymerize in the whole process and block the equipment. Basically, the equipment must be stopped for cleaning within a month. It is difficult to guarantee continuous production