Method for separating indene, naphthalene and methylnaphthalene from heavy benzol through low temperature side stream fractionation

Abstract

The invention discloses a method for separating indene, naphthalene and methylnaphthalene from heavy benzol through low temperature side stream fractionation. The method comprises the following steps: firstly, heavy benzol oil, light and heavy components of which are removed, is taken as raw material, and the heavy benzol oil is fed into a negative pressure side stream rectification column through a pump; secondly, 130 to 132 DEG C distillation cut at the top of the rectification column is cut when the operating pressure is 0.2atm, a part of the distillation cut flows back after being conducted to heat exchange through a heat exchanger, and the other part is served as indene products to enter an indene storage tank; thirdly, 195 to 200 DEG C distillation cut at the top of the rectification column is conducted to side stream cut, and the distillation cut is served as industrial naphthalene products to enter a naphthalene storage tank after being conducted to heat exchange through the heat exchanger; and fourthly, a part of material at the bottom of the rectification column returns to the bottom of the rectification column after being heated to be 240 to 245 DEG C, and the other part is served as methylnaphthalene products to enter a finished product storage tank. The method overcomes the deficiencies of the traditional technology, and as the method adopts single-column operation, compared with a conventionally used two-column common distillation method, the method has the advantages that the equipment cost and energy consumption are saved, as negative pressure control is adopted, the operating temperature is greatly reduced, indene polymerization is reduced, and the recovery ratio of indene is increased.

Description

technical field [0001] The invention relates to a chemical separation method, in particular to a method for separating indene, naphthalene and methylnaphthalene from heavy benzene by low-temperature side line rectification. Background technique [0002] Heavy benzene is a by-product of benzene processing, and its output accounts for about 10% of the total crude benzene. Heavy benzene is rich in available resources, mainly including light oil, trimethylbenzene, industrial naphthalene, methylnaphthalene, biphenyl, quinoline, indene, etc. Due to the complex components and difficult separation of heavy benzene, no breakthrough has been made in the key technology of separation in China, the degree of deep processing is very low, and the low level of technology restricts the development of the industry, and also causes the waste of this part of resources. [0003] The most important components in heavy benzene are naphthalene, indene and methylnaphthalene, and the content of...

AI Technical Summary

Problems solved by technology

[0005] The disadvantages of two-tower atmospheric distillation mainly lie in two aspects. One is that the two-tower process requires higher equipment cost and energy consumption. The other is that due to the high operating temperature, it is easy to cause the polymerization of indene, which affects the product quality and yield.

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