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Method for separating styrene from hydrocarbon mixture by extractive distillation

A hydrocarbon mixture, extractive distillation technology, applied in distillation purification/separation, organic chemistry, etc., can solve the problems of affecting heating effect, trouble, easy scaling of plug-in heaters, etc., to increase operating time, prevent polymerization, regeneration The effect of temperature reduction

Active Publication Date: 2014-03-26
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Plug-in heaters are easy to scale and affect the heating effect. Once scale is formed, it needs to be stopped and cleaned, which is not only troublesome, but also affects the long-term stable operation of the entire device

Method used

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  • Method for separating styrene from hydrocarbon mixture by extractive distillation
  • Method for separating styrene from hydrocarbon mixture by extractive distillation
  • Method for separating styrene from hydrocarbon mixture by extractive distillation

Examples

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Effect test

example 1

[0043] pyrolysis gasoline C 8 The distillate is the raw material, and its composition is shown in Table 1. according to figure 1 The shown flow process carries out extraction rectification to described raw material, reclaims styrene wherein, the composite solvent used contains the main solvent sulfolane of 99 mass %, the auxiliary solvent 4-methoxyphenol of 0.5 mass % and the water of 0.5 mass % , the polymerization inhibitor is 25% by mass of 4-hydroxyl-2,2,6,6-tetramethylpiperidine nitroxide radical (OH-TEMPO), 55% by mass of 4,6-dinitro-2- Secondary butylphenol (DNBP) and 20% by mass of N,N-diethylhydroxylamine, the mass ratio of the injected polymerization inhibitor to the raw material is 300μg / g, the solvent regeneration adopts reduced-pressure falling-film evaporation, and passes through the falling-film evaporator Combined with the solvent regeneration tower.

[0044] The number of theoretical plates in the extractive distillation column is 70, and the composite solv...

example 2

[0053] By the method of example 1 from pyrolysis gasoline C 8 Separation of styrene in the fraction, the difference is that the composite solvent used contains 88% by mass of the main solvent sulfolane, 5% by mass of 2-methoxyphenol, 6.5% by mass of triethylene glycol monomethyl ether co-solvent and 0.5% by mass of water , the operating conditions and results of each column are shown in Table 3.

example 3

[0055] By the method of example 1 from pyrolysis gasoline C 8 Separation of styrene in the fraction, the difference is that the inhibitor used is 35% by mass of tris (2,2,6,6-tetramethylpiperidinyl nitroxide free radical) phosphite, 35% by mass of 2,6 -Dinitro-p-cresol (DNPC), 30% by mass of N,N-diethylhydroxylamine, the mass ratio of polymerization inhibitor to raw material is 200 μg / g, the operating conditions and results of each tower are shown in Table 3.

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Abstract

The invention discloses a method for separating styrene from a hydrocarbon mixture by extractive distillation. The method comprises the following steps: performing extractive distillation on the hydrocarbon mixture with a compound solvent in the presence of a polymerization inhibitor; after extractive distillation, feeding a styrene-containing rich solvent into a solvent recovery tower, and separating styrene and a compound lean solvent out; removing high-boiling-point impurities from a part of the compound lean solvent with a falling film evaporation method to regenerate the solvent; feeding the regenerated compound lean solvent into the solvent recovery tower once again, wherein the compound solvent comprises 80-99 mass percent of a major solvent, 0.01-19 mass percent of a cosolvent and 0.1-2.0 mass percent of water; the major solvent is selected from sulfone compounds; the cosolvent is selected from metoxyphenol and / or ethylene glycol monomethyl ether; the polymerization inhibitor contains 10-60 mass percent of free radicals of nitroxide, 30-70 mass percent of nitrophenol and derivatives thereof, and 5-35 mass percent of N,N-diethylhydroxylamine. Through the method, the polymerization of styrene in an extractive distillation process can be reduced to the maximum extent, and the stable running period of an extractive distillation device is effectively prolonged.

Description

technical field [0001] The invention relates to a method for extracting and rectifying the separation of styrene, in particular to a method for extracting and rectifying the separation of styrene from hydrocarbon mixtures. Background technique [0002] Styrene monomer is an important basic organic chemical raw material, and it is also widely used in coatings, pesticides, and medicine. According to statistics, the steam pyrolysis gasoline by-product of the ethylene cracking unit contains 3-5% styrene. Due to the difference in raw materials for a set of 1 million tons / year ethylene plant, the styrene content in the pyrolysis gasoline is 20,000-30,000 tons / year . In the existing process of dealing with pyrolysis gasoline, this part of styrene is hydrogenated into ethylbenzene, which is stored in C 8 In the distillate, this ethylbenzene-rich C 8 The distillate is not ideal for supplying the downstream p-xylene unit as raw material. If ultra-rectification is used to separate ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/46C07C7/08
Inventor 田龙胜唐文成赵明张云明边志凤高思亮
Owner CHINA PETROLEUM & CHEM CORP
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