摘要:
A process for co-producing para-xylene and styrene from a feed (1) of hydrocarbons containing xylenes and ethylbenzene is described, the process comprising the following succession of steps: a step for separating the feed in a simulated moving bed in an adsorption column (6) containing beds of an adsorbent, from which an extract that is rich in para-xylene (7a) of at least 99.7% purity and at least one raffinate (7b) containing ethylbenzene, ortho-xylene, meta-xylene and a very small quantity of para-xylene is withdrawn; a step for dehydrogenating (10) the ethylbenzene contained in the raffinate (7b) to styrene; at least one step for primary separation of the stream (11) from the dehydrogenation step (10), to eliminate by-products; a step for separating the purified mixture (18) derived from the stream (11) containing styrene, unconverted ethylbenzene, meta-xylene and ortho-xylene, from which a stream (21a) that is rich in styrene of at least 99.8% purity and a stream (21b) containing unconverted ethylbenzene, meta-xylene and ortho-xylene is withdrawn; and a step for isomerising the stream (21b), the effluent being recycled to the adsorption column (6).
摘要:
A process for co-producing para-xylene and styrene from a feed (1) of hydrocarbons containing xylenes and ethylbenzene is described, the process comprising the following succession of steps: a step for separating the feed in a simulated moving bed in an adsorption column (6) containing beds of an adsorbent, from which an extract that is rich in para-xylene (7a) of at least 99.7% purity and at least one raffinate (7b) containing ethylbenzene, ortho-xylene, meta-xylene and a very small quantity of para-xylene is withdrawn; a step for dehydrogenating (10) the ethylbenzene contained in the raffinate (7b) to styrene; at least one step for primary separation of the stream (11) from the dehydrogenation step (10), to eliminate by-products; a step for separating the purified mixture (18) derived from the stream (11) containing styrene, unconverted ethylbenzene, meta-xylene and ortho-xylene, from which a stream (21a) that is rich in styrene of at least 99.8% purity and a stream (21b) containing unconverted ethylbenzene, meta-xylene and ortho-xylene is withdrawn; and a step for isomerising the stream (21b), the effluent being recycled to the adsorption column (6).
摘要:
A process for co-production of paraxylene, metaxylene and/or orthoxylene from a hydrocarbon feedstock (1) that comprises [1] a separation stage of the feedstock in a simulated moving bed in a chromatographic column (9) that contains a number of beds of an adsorbent, interconnected in a loop, is described, whereby said column comprises an injection (3) of the feedstock, a draw-off (10) of an extract that consists of paraxylene and desorbent, an intermediate fraction (11) (extract or raffinate) that contains ethylbenzene, and a raffinate (12) that contains a mixture of metaxylene and orthoxylene that is virtually free of ethylbenzene and paraxylene and [2] a crystallization stage (27) 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.
摘要:
A coproduction process for ortho-xylene and para-xylene starting with a batch of hydrocarbons comprises a simulated counter-current fluidized bed system in a chromatographic column (6) containing at least five zones, comprising injection (1) of the batch and injection (2) of desorption agent and delivering an extract (3), a refined product (5), and an intermediate refined product (4). Refined product (5), richer in ortho-xylene than the intermediate refined product, is distilled (9) to extract desorption agent (15) and is injection, according to the second step of the process, into a simulated counter-current fluidized bed system (17) delivering an extract (18) and a refined product (19) continuously.
摘要:
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%.
摘要:
The present invention relates to agglomerated zeolitic adsorbents containing zeolite X and an inert binder, the inert binder containing at least 80% by weight of clay which has undergone zeolitization by the action of an alkaline solution, the zeolite X having with an Si/Al ratio such that 1.15
摘要:
The invention relates to a process for converting a hydrocarbon charge of linear and branched olefins, comprises the following stages: a) a stage of membrane separation of the hydrocarbon charge under conditions making it possible to produce a cut β containing the majority of the linear olefins present in said charge, and a cut γ containing the majority of the branched olefins, b) a stage of treatment of the linear olefins contained in the effluents originating from the membrane separation stage (cut β) under moderate oligomerization conditions, c) a stage of distillation separation of the effluents originating from the oligomerization stage into at least two cuts, d) a stage of hydrogenation of the cut η under conditions for obtaining a gas oil with a high cetane number.
摘要:
The invention relates to a process for conversion of a gasoline-range hydrocarbon feed into a gasoline fraction with a higher octane rating than that of the feedstream, and a gasoil fraction with a cetane number higher than 45, including the following steps: a) a membrane separation step (B) applied to the hydrocarbon feed under conditions enabling selective separation of the majority of the linear olefins present in said feed and constituting the β fraction, the fraction containing the majority of the branched olefins, termed the γ fraction, constituting a gasoline with a high octane rating, greater than that of the feed, b) an oligomerisation step (C) applied to the linear olefins (β fraction) contained in the effluent stream from the membrane separation step (B) under moderate oligomerisation conditions, c) a distillation separation step (D) applied to the effluent stream arising from the oligomerisation step in at least two fractions, d) a hydrogenation step (E) applied to one of the fractions obtained at step c).
摘要:
The present invention relates to agglomerated zeolitic adsorbents containing zeolite X and an inert binder, the inert binder containing at least 80% by weight of clay which has undergone zeolitization by the action of an alkaline solution, the zeolite X having with an Si/Al ratio such that 1.15
摘要:
A process for separating para-xylene from a C.sub.8 feed in a simulated moving bed comprises a step for adsorption on a zeolite and desorption using a desorbent delivering an extract and a raffinate, and an extract crystallization step. A stream of water is introduced into the feed, into the desorbent and/or into the stream for recycling one flux in the column, such that the weighted average of the amounts of water measured in the extract and in the raffinate is in the range 1 to 200 ppm. The ratio S/F of the desorbent flow rate to that of the feed during the adsorption and desorption step is in the range 0.6 to 2.5.