Method for extracting mesitylene fraction rich in hydrocracking C 9 by combination of continuous lateral line distillation and extractive distillation

Abstract

The invention discloses a method for extracting mesitylene fractions rich in hydrocracking C 9 by combination of continuous lateral line distillation and extractive distillation, comprising the following steps: (1) material hydrocracking C 9 aromatic is added into a continuous lateral line distillation tower, the tower bottom is heated, fractions 2 with a boiling range of 155 DEG C to 170 DEG C, fractions 3 with a boiling range of 170 DEG C to 190 DEG C and fractions 4 with a boiling range of 190 DEG C to 210 DEG C are obtained at the same time after pretreatment, content of mesitylene in the fractions 2 achieves above 90 percent, and a little mesitylene and a great deal of heavy aromatic are contained in the fractions 3 and the fractions 4; (2) the fractions 2 enter an extractive distillation tower, content of mesitylene fractions on the top 5 of the extractive distillation tower achieves above 98 percent, and fractions 6 containing a great deal of extraction solvent and heavy aromatic hydrocarbon are left at the tower bottom; (3) the fractions 6 are treated through a solvent recovery tower, heavy aromatic fractions 7 are left on the top of the solvent recovery tower, a tower reactor extracts solvent, and the solvent flows into the extractive distillation tower for recycling use. The invention only needs one distillation tower, obviously improves the efficiency, and lowers the energy consumption and the cost.

Description

technical field [0001] The invention relates to a chemical separation method, in particular to a combination of continuous side line rectification and extractive rectification to extract hydrocracking C 9 A method for enriching trimethylbenzene fractions. Background technique [0002] cleavage C 9 Aromatics are by-products of ethylene plants, accounting for about 10-20% of the total ethylene production. Currently, my country cracks C 9 The yield of aromatics is 1.06×10 6 t / a or more, will reach 1.1×10 in 2010 6 t / a or more. cleavage C 9 Aromatics vary with the cracking raw materials, cracking depth and cracking process, and the composition is extremely complex, and the color is dark and the smell is strong. Refining it by hydrogenation can improve its quality and allow it to be used effectively. Currently, hydrocracking C 9 Aromatics are mainly used in the following aspects: Hydrocracking C 9 Production of petroleum resins from aromatics; hydrocracking C 9 Prepara...

AI Technical Summary

Problems solved by technology

The cryogenic crystallization method is a method of separation by using the difference in the melting point of aromatic hydrocarbons. It operates at low temperature, requires large investment, high energy consumption, and poor economic indicators; the extraction extraction / isomerization method uses the relative alkalinity of each component in aromatic hydrocarbons The method of separating and refining trimethylbenzene from the by-product of xylene isomerization has successfully separated and refined trimethylbenzene, but the organic reaction is very complicated, and there are side effects such as disproportionation and alkylation during the isomerization reaction. There are many by-products in the reaction; the alkylation method is to carry out an alkylation reaction with benzene under the action of a heterogeneous acidic catalyst, and methyl and ethyl benzene can be selectively converted into light components such as toluene or ethylbenzene, and light components It can be easily separated from trimethylbenzene by rectification, and the catalyst is difficult to match; the extractive distillation method mainly uses the extraction solvent to increase the relative volatility between the components, so as to achieve the purpose of separation. In this method The choice of extraction solvent is the key

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