Energy-saving efficient aromatic hydrocarbon extraction system

Abstract

The invention provides an aromatic hydrocarbon extraction system. The aromatic hydrocarbon extraction system comprises an extractive distillation tower, a solvent regeneration tower and a high lean solvent regeneration tower, wherein the extractive distillation tower is connected with a raw material charging pipeline and a supplement solvent charging pipeline; the top of the extractive distillation tower is provided with a non-aromatic hydrocarbon recovery pipeline; the bottom of the extractive distillation tower is provided with an aromatic hydrocarbon mixture recovery pipeline; the aromatic hydrocarbon mixture recovery pipeline communicates with the solvent regeneration tower; the top of the solvent regeneration tower is provided with a primary aromatic hydrocarbon recovery pipeline; the bottom of the solvent regeneration tower is provided with a lean solvent recovery pipeline; the lean solvent recovery pipeline communicates with the high lean solvent regeneration tower; the lean solvent recovery pipeline is further provided with a backflow branch; the backflow branch communicates with the extractive distillation tower; the top of the high lean solvent regeneration tower is provided with a secondary aromatic hydrocarbon recovery pipeline; the bottom of the high lean solvent regeneration tower is provided with a high lean solvent recovery pipeline; the high lean solvent recovery pipeline communicates with the extractive distillation tower. By adopting the energy-saving efficient aromatic hydrocarbon extraction system, the aromatic hydrocarbon yield on the top of the extractive distillation tower can be increased.

Description

technical field [0001] The invention belongs to the technical field of aromatic hydrocarbon extraction and rectification, and in particular relates to an energy-saving and high-efficiency aromatic hydrocarbon extraction system. Background technique [0002] In terms of refining coking crude benzene, the methods commonly used at home and abroad include pickling and hydrogenation. In order to meet the requirements of product quality, yield and environmental protection, the hydrotreating of crude benzene has become the main trend of coking crude benzene price in the future. The hydrogenated oil obtained by hydrogenating crude benzene contains aromatic components (benzene and toluene) and some non-aromatic hydrocarbons such as heptane, cyclohexane, and dimethylpentane, which have a similar boiling point to benzene and are easy to form an azeotropic system with benzene. Methods for separating aromatics include liquid / liquid extraction, adsorption, extractive distillation, etc. A...

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Problems solved by technology

[0003] However, in the current industrial production process, the content of aromatics in the non-aromatic products at the top of the extractive distillation tower is relatively high, which reduces the yield of aromatics

The content of aromatics in non-aromatic products is related to the impurity content of the regenerated lean solvent. To increase the yield of aromatics, the purity of the regenerated lean solvent must be further improved, but even a small amount of purification of the regenerated lean solvent will greatly increase Liquid load, and then increase the diameter of the regeneration tower, not only the high energy consumption of the system, but also the increase of equipment investment

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