Aromatic hydrocarbon purification apparatus and process used in hydrofining of coking crude benzene

Abstract

The invention provides an aromatic hydrocarbon purification apparatus and process used in hydrofining of coking crude benzene. The apparatus comprises an extractive distillation tower, a liquid-liquid extraction tower, an aromatic hydrocarbon stripping tower, a crude benzene preheater, a hydrogenated oil preheater, a cooler, an air cooler, a raw material mixer, a discharging mixer and a distributor. The process comprises the following steps: allowing raw hydrogenated oil and a poor solvent N-formyl morpholine to enter into the extractive distillation tower, coupling a gas phase and a liquid phase in the extractive distillation tower and the liquid-liquid extraction tower, extracting a gas phase at a side line of a distillation section of the extractive distillation tower, mixing the gas phase with a tower top discharge, cooling an obtained mixture and allowing the mixture to enter into the liquid-liquid extraction tower for separation into two phases; re-introducing an aromatic hydrocarbon-rich heavy phase into the top of the extractive distillation tower as reflux, with an aromatic hydrocarbon-poor light phase mainly being non-aromatic hydrocarbons; and allowing a rich solvent at the bottom of the extractive distillation tower to enter into the aromatic hydrocarbon stripping tower for separation, wherein pure aromatic hydrocarbon is obtained at the top of the aromatic hydrocarbon stripping tower, and the poor solvent N-formyl morpholine is obtained at the bottom of the aromatic hydrocarbon stripping tower and is recycled. In the flow path of the process, process system engineering methodology is employed for realizing integration of mass and heat and optimization of a comprehensive heat exchange network, thereby realizing recovery of waste heat, improvement of a separation effect of aromatic hydrocarbon and reduction in operating cost.

Description

technical field [0001] The invention belongs to the field of petrochemical industry, and relates to an aromatic hydrocarbon purification device and process used in coking crude benzene hydrogenation refining. N-formylmorpholine is used as a solvent to separate and purify aromatic hydrocarbons from a mixture of aromatic hydrocarbons and non-aromatic hydrocarbons. Background technique [0002] At present, the solvents used in industry for the extraction of aromatics include N-formylmorpholine, sulfolane and N-methylpyrrolidone. N-formylmorpholine has good selectivity and solubility, and its corresponding extraction process has many significant advantages such as less solvent consumption, low energy consumption, high product purity and yield, so it is widely used. According to the unit operation characteristics, aromatics extraction can be divided into liquid-liquid extraction and extractive distillation. Liquid-liquid extraction is a unit operation that uses the difference in...

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Problems solved by technology

[0006] US Patent Number 3944483, US Patent Number 4488936, US Patent Number 4776927, etc. all describe the aromatics extraction technology, and gradually transform the existing technology, but none of them involve changes in the distribution of components in the operating unit, and Respond to the coupling configuration of different separation methods to improve the separation effect of aromatics combined process

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