Extractive distillation process in hydrofining process of crude benzene

Abstract

The invention relates to an extractive distillation process in the hydrofining process of crude benzene. The process comprises the following steps: 1) extractant enters from the top of an extractive distillation column, hydrotreated oil enters from the middle of the extractive distillation column; and the tower top product enters a stripping tower in a gaseous phase mode; 2) the tower top productof the extractive distillation column enters the stripping tower to perform distillation purification, the non-arene product in the top of the stripping tower is discharged, the heavy phase product at the bottom of the stripping tower is sent to a liquid-liquid separating tank by a pump; and 3) in the liquid-liquid separating tank, liquid is collected to obtain a heavy phase product and a light phase product, the heavy phase product containing extractant and arene are sent back to the extractive distillation column; and the light phase product, namely non-arene is sent back to the stripping tower. By adopting the process, the heavy non-arene can be effectively prevented from being sent to the extraction section of the extractive distillation column and the quality of product can be increased; and the total height of the extractive distillation column can be reduced, the manual operation is convenient to perform and the problem that the lack of heat caused by the overhigh extractive distillation column can be avoided.

Description

technical field [0001] The invention relates to an extraction and distillation process in the hydrogenation and refining process of crude benzene raw materials. Background technique [0002] At present, in the industrial crude benzene refining process, the hydrogenated oil after the hydrogenation section, because the low-temperature hydrogenation reaction conditions are gentle, a large amount of non-aromatic hydrocarbons are accompanied in the hydrogenated oil, if not removed, it will inevitably be mixed in the product, which will greatly affect Product quality, so the separation after low-temperature hydrogenation must first remove non-aromatics. Since the boiling point of non-aromatic hydrocarbons is very close to that of benzene, it is difficult to remove them by ordinary distillation, so effective separation methods are required. [0003] At present, the commonly used methods for separating non-aromatics in hydrogenated oil are divided into two types of processes: liqui...

AI Technical Summary

Problems solved by technology

Causes the height of the extractive distillation column to be unsuitable for on-site staff to operate

It is about 20 meters higher than other distillation towers in the whole device, so the set operation platform is not conducive to the operation of on-site employees

At the same time, due to the high height of the whole tower, it is easy to cause heat loss in the middle, resulting in insufficient heat supply, so that the heavier components in the non-aromatic hydrocarbons that escape from the top of the tower are easy to return to the extraction section of the extractive distillation tower under the action of reflux

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