Institut Francais Du Pe'trole

Ifp Energies Nouvelles

Axens

Gérard Hotier

Philibert Leflaive

Alain Methivier

Luc Wolff

Pierre Renard

Damien Leinekugel Le Cocq

Isabelle Prevost

Fabian Lambert

Gilles Ferschneider

Pierre-Yves Le Goff

Jean-Christophe Viguie

Frédéric Augier

Jérôme Pigourier

A process for producing para-xylene from a hydrocarbon feed is described in which an adsorption column operating as a simulated moving bed with at least five zones delivers an extract, a 2-raffinate and an intermediate raffinate. The extract is distilled and the distillate is optionally re-crystallized to recover para-xylene with a purity of at least 99.7%. The 2-raffinate is distilled then isomerized in a reactor preferably operating in the liquid phase and at a low temperature. The intermediate raffinate with an enriched ethylbenzene content is distilled then isomerized in the vapour phase.

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

A simulated moving bed (SMB) separation device comprises at least one column, beds of adsorbent arranged in this column, trays Pi with a chamber Ci for distribution and extraction of fluids, a multi-way rotary valve for the distribution of the fluids feeding or leaving said trays, and junction lines Li between this valve and said trays. The SMB device also comprises a plurality of bypass lines Li,i+between adjacent lines, these bypasses being outside the multi-way rotary valve and situated in proximity to this valve, for the circulation of rinsing liquids with a small or zero concentration gradient. The invention makes it possible to use all types of distribution and extraction trays and all types of adsorbent loading, while preserving a high level of product purity. Application of the separation devices is in particular to the separation of paraxylene or metaxylene from a C8 aromatic charge.

Simulated moving bed separation process and device

Device and process for separating at least one compound from a mixture in a simulated moving bed, comprising:

System for injecting a by-pass fluid in a separation method in a simulated moving bed

For use in a separation column, a mat element or a beam element has at least: an upper part; at least one distributor-collector part () having one or more secondary orifices () and at least one main orifice (), whereby the passage sections of orifices () and () are different; and a lower part (). The distributor-collector part or parts () arranged between the upper part () and the lower part (). A sealing element () arranged between the distributor-collector part () and the upper part (), and a sealing element () arranged between the distributor-collector part () and the lower part (). A separation element () arranged at distributor-collector part (), thus delimiting two spaces () for circulation of fluids.

Mat element that has a distribution function

A process for co-production of paraxylene, metaxylene and/or orthoxylene from a hydrocarbon feedstock () that comprises [1] a separation stage of the feedstock in a simulated moving bed in a chromatographic column () that contains a number of beds of an adsorbent, interconnected in a loop, is described, whereby said column comprises an injection () of the feedstock, a draw-off () of an extract that consists of paraxylene and desorbent, an intermediate fraction () (extract or raffinate) that contains ethylbenzene, and a raffinate () that contains a mixture of metaxylene and orthoxylene that is virtually free of ethylbenzene and paraxylene and [2] a crystallization stage () of the metaxylene and/or orthoxylene fraction. Upstream from the adsorption zone and/or upstream from the crystallization zone, it is possible to distill the entering mixture to produce an orthoxylene-enriched fraction at the bottom and a metaxylene-enriched fraction at the top.

Process for co-production of paraxylene, metaxylene and/or orthoxylene

A process is described for co-producing metaxylene and paraxylene from a hydrocarbon feed comprising two separation steps. The first step of the process is a counter-current simulated moving bed system in a chromatographic column containing at least five zones, comprising injecting the feed and injecting a desorbent and delivering an extract, a raffinate and an intermediate raffinate either continuously or discontinuously. The extract is distilled to obtain a paraxylene with a purity of at least 99.7%. The raffinate, which is richer in metaxylene, is distilled to extract the desorbent and injected into a counter-current simulated moving bed continuously delivering an extract and a raffinate. One of these two streams is enriched in metaxylene. The most metaxylene-rich stream is distilled to obtain metaxylene with a purity of more than 99%.

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Rueil Malmaison, France

Gérard Hotier