Method for producing paraxylene comprising an adsorption step and two isomerization steps

一种对二甲苯、异构化的技术,应用在异构化制烃、吸附纯化/分离、化学仪器和方法等方向,能够解决二甲苯纯度二甲苯收率限制等问题,达到成本低的效果

Active Publication Date: 2006-12-27
INST FR DU PETROLE
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0022] These documents describe the discharge of two different raffinates from a simulated moving bed adsorption column, but there are limitations in the purity of para-xylene obtained or in the yield of para-xylene related to the co-production of other isomers

Method used

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  • Method for producing paraxylene comprising an adsorption step and two isomerization steps
  • Method for producing paraxylene comprising an adsorption step and two isomerization steps

Examples

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Embodiment 2

[0116] Example 2 has the same loop, but with a capacity increase of 30% according to the invention.

Embodiment 1

[0117] Embodiment 1 (comparison)

[0118] This example illustrates the prior art and describes the aromatic compound loop shown in Figure 2, which consists of:

[0119] xylene column (CD2) for extracting C9 and C10 aromatics (stream 4) and feeding the stream (3) consisting essentially of C8 aromatics to the adsorption unit (LM6);

[0120] Simulated moving bed adsorption unit (LM6) with 4 zones, from which extract (7) and single raffinate (8) are discharged;

[0121] an isomerization unit (IS19), in which a part (14) of the raffinate (8) after removal of the desorbent by the distillation column (CD11) is fed;

[0122] • A p-xylene purification column (CD35) located downstream of the distillation column (CD10). Para-xylene (stream 37) with a purity of more than 99.7% is withdrawn from the bottom of the column (CD35).

[0123] The units used for flow rate are kilotons per year (kt / yr).

[0124] Feed (1) to the aromatics loop was obtained from reforming with a flow rate of 460...

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Abstract

Producing p-xylene from feed comprising xylenes, ethylbenzene and C9+ hydrocarbons comprises introducing feed to simulated moving bed adsorption unit to produce extract comprising p-xylene and desorbent, and intermediate raffinate comprising ethylbenzene and raffinate comprising m- and o-xylene; passing intermediate raffinate to vapor-phase isomerization unit and passing second raffinate to liquid- or vapor-phase isomerization unit.

Description

technical field [0001] The production of p-xylene has grown steadily at an average annual rate of 5-6% for 30 years. Paraxylene is used in the production of terephthalic acid and polyethylene terephthalate, which in turn are used in the synthesis of textiles, audio cassettes, video cassettes, bottles, and more generally plastics. [0002] To meet the growing demand for paraxylene, petrochemists can choose between increasing the capacity of existing plants or building new plants, which must be larger, since the break-even point for such plants is about 400,000 tons / year. [0003] The present invention satisfies both cases and is suitable for increasing the capacity of existing installations (often referred to as debottlenecking) since the modifications involved are relatively modest. [0004] All equipment in the existing production unit can be reused, with the addition of 1) an on-off valve per bed or a modified rotary valve in the adsorption section of the simulated moving ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/08C07C5/27C07C7/12C07C7/13
CPCC07C5/2737C07C5/2775C07C7/12B01D15/1821C07C7/13C07C15/08
Inventor P·勒夫莱维L·沃尔夫G·霍捷
Owner INST FR DU PETROLE
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