Method for extracting styrene in light cracked carbon nine aromatic hydrocarbons by single side line vacuum extraction

Abstract

A single-side-draw vacuum extraction method for styrene in light cracked C9 aromatic hydrocarbons is disclosed. Rectification and extractive rectification are integrated in a single-side-draw vacuum extraction tower to achieve separation of multiple components. The method adopts the single-side-draw vacuum extraction tower. Raw materials are added from the middle lower part of the tower. A mixture of a potassium salt and sulfolane is adopted as an extracting solvent and is fed from the middle upper part of the tower. A gas-phase side-draw material outlet is provided below the raw material feeding position. The degree of vacuum of the tower is controlled to be 0.088-0.090 MPa. The tower top temperature is 63.6-65.5 DEG C. The side-draw temperature is 75.2-76.9 DEG C. The styrene purity of which is higher than 96.1% is obtained after condensation of the side draw. A mixture containing the extracting solvent is discharged from the tower bottom and is treated and separated by a solvent recovering tower, and the extracting solvent is recycled. The method is simple in process. The styrene is high in purity and yield. The extractant is convenient to recover and reutilize. Process energy consumption is low.

Description

technical field [0001] The invention relates to a chemical separation method, in particular to a method for continuous single sideline decompression extraction and extraction of styrene in light cracked C9 aromatic hydrocarbons. Background technique [0002] Cracked C9 aromatics are by-products of ethylene plants, accounting for about 10-20% of the total ethylene production. At present, the output of cracked C9 aromatics in my country is 1.4×10 6 More than t / a, reaching 1.6×10 in 2013 6 t / a or more. The traditional process of cracking C9 aromatics generally uses rectification method to pretreat the raw materials first, and the raw materials are fractionated into light cracked C9 aromatics and heavy cracked C9 aromatics, and the light cracked C9 aromatics are converted into light by hydrogenation. As a raw material for xylene disproportionation or C9 solvent oil, heavy cracked C9 aromatics are used as raw materials for preparing C9 resin. Since cracked C9 aromatics contai...

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Problems solved by technology

Since cracked C9 aromatics contain a large amount of active ingredients, such as styrene and dicyclopentadiene, the content of styrene accounts for about 12%, and dicyclopentadiene accounts for about 22%. At present, multiple rectification methods are used to process styrene Recycling, the primary yield is only about 23%, and the styrene content is only 76%. The production process consumes a lot of energy and seriously wastes valuable resources such as styrene.

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