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Method of joint produce pare xylene and metaxylene including two stage separation

A m-xylene and p-xylene technology, applied in chemical instruments and methods, distillation purification/separation, adsorption purification/separation, etc., can solve problems such as separation difficulties and m-xylene purity difficulties, and achieve the effect of size reduction

Inactive Publication Date: 2002-11-13
INST FR DU PETROLE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the boiling points of these two products are very close (i.e. 139.12°C and 144.41°C, respectively), which makes it very difficult to separate the two compounds by distillation, requiring a large number of sieve plates with at least about 150-200 column
In addition, if the mixed meta-xylene and ortho-xylene stream for which separation is sought contains impurities para-xylene and ethylbenzene, these impurities will be concentrated in meta-xylene, making it difficult to achieve a purity of meta-xylene greater than 99.0%

Method used

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  • Method of joint produce pare xylene and metaxylene including two stage separation
  • Method of joint produce pare xylene and metaxylene including two stage separation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Embodiment 1 (comparative example)

[0034] Use a feed containing a mixture of xylene and ethylbenzene, the weight composition of which is as follows:

[0035] PX: Paraxylene 22.6%

[0036] MX: m-xylene 49.9%

[0037] OX: o-xylene 21.9%

[0038] EB: Ethylbenzene 5.6%

[0039] 1 meter in section 2 1. In a cylindrical adsorber composed of 24 beds of X zeolite exchanged with barium, p-xylene is produced in 4 sections in a countercurrent simulated moving bed manner.

[0040] The operating conditions are as follows:

[0041] Material: 9.5 meters 3 / Hour

[0042] Solvent: 16.2 meters 3 / hour p-diethylbenzene

[0043] Extract: 9.6 meters 3 / Hour

[0044] Raffinate: 16.1 meters 3 / Hour

[0045] Circulation flow (in section 1): 48.2 meters 3 / Hour

[0046] Its structure is 5 beds, 9 beds, 8 beds and 2 beds in segments 1, 2, 3 and 4 respectively.

[0047] The switching time (cycle) of the valve is 70.8 seconds.

[0048] After distillation of p-diethylbenzene, the...

Embodiment 2

[0065] Use a feed containing a mixture of xylene and ethylbenzene, the weight composition of which is as follows:

[0066] PX: Paraxylene 22.6%

[0067] MX: m-xylene 49.9%

[0068] OX: o-xylene 21.9%

[0069] EB: Ethylbenzene 5.6%

[0070] 1 meter in section 2 , In a cylindrical adsorber composed of 24 beds of X zeolite exchanged with barium, p-xylene is produced in 5 sections in a countercurrent simulated moving bed manner. The raffinate (raffinate 2) and the intermediate raffinate were continuously removed.

[0071] The operating conditions are as follows:

[0072] Material: 9.5 meters 3 / Hour

[0073] Solvent: 16.2 meters 3 / hour p-diethylbenzene

[0074] Extract: 9.6 meters 3 / Hour

[0075] Intermediate raffinate: 10.1 meters 3 / Hour

[0076] Raffinate 2: 6.0 m 3 / Hour

[0077] Circulation flow (in section 1): 48.2 meters 3 / Hour

[0078] Its structure is 5 beds, 9 beds, 5 beds, 3 beds and 2 beds in segments 1, 2, 3A, 3B and 4 respectively.

[0079] The s...

Embodiment 3

[0098] Use more abundant ethylbenzene than embodiment 2, the material that contains xylene and ethylbenzene mixture, the weight composition of this material is as follows:

[0099] PX: p-xylene 21.1%

[0100] MX: m-xylene 48.9%

[0101] OX: o-xylene 21.4%

[0102] EB: Ethylbenzene 8.6%

[0103] 1 m in both sections 2 , Production of p-xylene in countercurrent simulated moving bed mode in a cylindrical adsorber consisting of 24 beds of X zeolite exchanged with barium. The raffinate (raffinate 2) and the intermediate raffinate were withdrawn continuously.

[0104] The operating conditions are as follows:

[0105] Material: 9.5 meters 3 / Hour

[0106] Solvent: 16.2 meters 3 / hour p-diethylbenzene

[0107] Extract: 9.5 meters 3 / Hour

[0108] Intermediate raffinate: 12.05 meters 3 / Hour

[0109] Raffinate 2: 4.15 m 3 / Hour

[0110] Circulation flow (in section 1): 48.2 meters 3 / Hour

[0111] Its structure is 5 beds, 9 beds, 5 beds, 3 beds and 2 beds in segments 1...

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Abstract

A process for the co-production of m-xylene and p-xylene from hydrocarbon feedstocks is described, which involves two separate steps. The first separation step of the method is a simulated moving bed system in a countercurrent manner in the chromatographic column. The chromatographic column contains at least five sections, including continuous or intermittent injection of material, injection of desorbent, extraction of extract, raffinate and intermediate raffinate. Distill the extract to obtain p-xylene with a purity of at least 99.7%. The raffinate rich in m-xylene is distilled to extract the desorbent, and then injected into the countercurrent simulated moving bed to continuously provide the extract and raffinate. One of these two streams is rich in m-xylene. Distillation of the most m-xylene-rich stream yields m-xylene with a purity greater than 99%.

Description

technical field [0001] The present invention relates to a process for the co-production of para-xylene and meta-xylene from a hydrocarbon material containing para-xylene and meta-xylene, the process comprising two stages of separation. Background technique [0002] The production of high-purity p-xylene by adsorption separation is well known in the prior art. This market has been greatly developed and they are aimed at the production of terephthalic acid, phthalic anhydride and polyethylene terephthalate resins. The market for m-xylene, on the contrary, is limited and its purpose is the production of isophthalic acid. However, processes for the production of high-purity meta-xylene are known from the prior art, eg US 4 326 092, US 5 382 747 and US 5 900 523. Recently, it has been learned that adding a small amount of polyethylene isophthalate to polyethylene terephthalate can improve the properties of polyethylene terephthalate. Therefore, there has become a lot of intere...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C7/04C07C7/00C07C7/12C07C7/13C07C15/08
CPCC07C7/005C07C7/13C07C15/08
Inventor P·勒弗莱维A·梅蒂维尔G·霍蒂尔
Owner INST FR DU PETROLE
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