Decoloring method of crude styrene obtained through extractive rectification of pyrolysis gasoline C8 fraction

A technology of crude styrene and pyrolysis gasoline, applied in the direction of chemical change purification/separation, organic chemistry, etc., can solve problems such as water content, equipment corrosion, etc., achieve the effects of reducing sewage discharge, preventing equipment corrosion, and reducing acid content

Active Publication Date: 2015-01-14
CHINA PETROLEUM & CHEM CORP +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] CN101429091A has introduced a kind of method of styrene decolorization, also is to utilize maleic anhydride decolorization, this method adds decolorant in the extractive distillation solvent, in the extractive distillation process that pyrolysis gasoline reclaims styrene, directly the styrene-containing The raw material is decolorized, but the extractive distillation process generally contains water, and how to avoid equipment corrosion during the extraction process is not mentioned

Method used

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  • Decoloring method of crude styrene obtained through extractive rectification of pyrolysis gasoline C8 fraction

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0027] according to figure 1 Process for pyrolysis gasoline C 8 The distillate is decolorized with the crude styrene obtained by extractive distillation.

[0028] pyrolysis gasoline C 8 The crude styrene obtained by extraction and rectification of the distillate has a purity ≥ 99.7% by mass and a water content of 594 μg / g, and enters the middle part of the dehydration tower 101 . The number of plates in the dehydration tower is 20, the reflux ratio at the top of the tower is 1, the pressure at the top of the tower is 8kPa, and the distillation temperature at the top of the tower is 62°C. The azeotrope of styrene and water is obtained at the top of the tower. After the water is separated from the water in the condensate tank 102, the water is discharged from the system, and a part of the oil is returned to the feed pipeline, and the other part is used as a reflux at the top of the tower. The water content of the dehydrated styrene obtained at the bottom of the tower is <40 μ...

example 2

[0031] By the method of example 1 to pyrolysis gasoline C 8The distillate is decolorized with the crude styrene obtained by extractive distillation. The difference is that benzene is added to the crude styrene as a dehydrating agent, the amount of benzene added is 3% by mass of the feed amount of the dehydration tower, the number of dehydration trays is 25, the top reflux ratio is 1.2, the pressure is 60kPa, and the top distillation temperature 105°C. The stream discharged at the top of the dehydration tower 101 is an azeotrope of benzene and water and a small amount of styrene. After the water separation in the condensate tank 102, the resulting oil phase is benzene and a small amount of styrene, and a part is used as the top reflux. The rest is used as a dehydrating agent and mixed with raw materials. The water content of the dehydrated styrene obtained at the bottom of the dehydration tower is ≤10 μg / g.

[0032] In the decolorizer tank 103, there is a dioctyl phthalate s...

example 3

[0034] By the method of example 1 to pyrolysis gasoline C 8 The distillate is decolorized with the crude styrene obtained by extractive distillation. The difference is that benzene is added to the crude styrene as a dehydrating agent, the amount of benzene added is 3% by mass of the feed amount of the dehydration tower, the number of dehydration trays is 30, the top reflux ratio is 0.8, the pressure is 60kPa, and the top distillation temperature 105°C. The stream discharged at the top of the dehydration tower 101 is an azeotrope of benzene and water and a small amount of styrene. After the water separation in the condensate tank 102, the resulting oil phase is benzene and a small amount of styrene, and a part is used as the top reflux. The rest is used as a dehydrating agent and mixed with raw materials. The water content of the dehydrated styrene obtained at the bottom of the dehydration tower is ≤10 μg / g.

[0035] The decolorizer in the decolorizer tank 103 is dioctyl pht...

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Abstract

A decoloring method of crude styrene obtained through extractive rectification of a pyrolysis gasoline C8 fraction includes the steps: sending crude styrene into a dehydration tower, carrying out rectification dehydration, separating out water from the tower top, adding a decoloring agent into dehydrated styrene obtained at the tower bottom, mixing, then sending into a styrene rectification tower, carrying out rectification, to obtain a styrene product at the tower top, and discharging a heavy component from the tower bottom. The method can make the platinum-cobalt chroma of the styrene product less than or equal to 10, allows the styrene product to reach product quality standard requirements, and can greatly reduce risks of equipment corrosion and sewage discharge capacity.

Description

technical field [0001] The invention relates to a method for decolorizing organic compounds, in particular to a method for decolorizing and refining crude styrene recovered from pyrolysis gasoline through extraction and rectification. Background technique [0002] Styrene is an important basic organic chemical raw material. According to statistics, steam pyrolysis gasoline by-product of ethylene cracking unit contains 3-5% by mass of styrene, and a set of 1 million tons / year ethylene plant contains about 20,000-30,000 styrene in pyrolysis gasoline due to the difference in raw materials. tons / year. In the existing process of dealing with pyrolysis gasoline, this part of styrene is converted into ethylbenzene by hydrogenation and stored in C 8 in fractions. In contrast, direct distillation of styrene from pyrolysis gasoline is an attractive technology. The feasible way to separate styrene from unhydrogenated pyrolysis gasoline is to use extractive distillation. The basic p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/46C07C7/148
Inventor 赵明田龙胜唐文成张云明边志凤高思亮
Owner CHINA PETROLEUM & CHEM CORP
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