摘要:
A process for the production of at least one isomer of xylenes comprising a simulated moving-bed adsorption (8) of a C8-aromatic feedstock (1) that delivers a paraxylene-rich fraction (9) that is optionally purified after a distillation (16) by at least one high-temperature crystallization (5) and a fraction (10) that is low in paraxylene is described. Fraction (10) is distilled and then isomerized (21) in the presence of an EUO-structural-type catalyst. The lightest hydrocarbons are removed from the isomerization effluent in a first distillation (23) then naphthenes in a second distillation (26), and distilled isomerization effluent (2) that results therefrom is recycled at least in part in adsorption (8). A mother liquor (3) that results from the crystallization stage is recycled at least in part in adsorption (8).
摘要:
The invention relates to a process for the production of at least one isomer of xylenes, preferably paraxylene, as well as benzene, starting from a C8-aromatic fraction, whereby said process comprises a zone for separation of xylenes, a zone for isomerization of aromatic compounds with 8 carbon atoms used in the presence of a catalyst that comprises at least one EUO-structural-type zeolite that is selected from among the EU-1, TPZ-3, ZSM-50 zeolites and at least one metal of group VIII of the periodic table, and finally a transalkylation zone of C7- and C9-aromatic compounds. The invention makes it possible to produce paraxylene and benzene with a high yield, starting from a C8-aromatic fraction that comprises a large amount of ethylbenzene with improved performance levels of the isomerization stage and a good conversion of ethylbenzene in the transalkylation stage.
摘要:
A process for the production of at least one xylene isomer, paraxylene, metaxylene or orthoxylene from an aromatic feedstock that has 7 to 10 carbon atoms per molecule. The process comprises a stage for transalkylation of C7- and C9-aromatic compounds, a stage for separation of xylenes and a stage for isomerization of xylenes. The isomerization catalyst used in the process comprises at least one EUO zeolite composition whose crystals are grouped in aggregates that have a grain size with a value of Dv,90 less than or equal to 500 microns and at least one element of group VIII.
摘要:
The present invention concerns a process for preparing a zeolite with structure type EUO comprising at least one element X selected from silicon and germanium and at least one element T selected from iron, aluminium, gallium, boron, titanium, vanadium, zirconium, molybdenum, arsenic, antimony, chromium and manganese, characterized in that seeds of at least one zeolitic material are used comprising at least one element X′ selected from silicon and germanium and at least one element T′ selected from iron, aluminium, gallium, boron, titanium, vanadium, zirconium, molybdenum, arsenic, antimony, chromium and manganese with a ratio X′/T′ of less than 200, said seeds being different from the zeolite with structure type EUO being prepared. The present invention also concerns the use of the zeolite obtained as a catalyst in a process for converting hydrocarbon-containing feeds, as an adsorbent to control pollution and as a molecular sieve for separation, and more particularly as a catalyst in a process for isomerizing aromatic compounds containing 8 carbon atoms.
摘要:
The present invention relates to a process for isomerizing aromatic compounds containing 8 carbon atoms, the catalysts containing at least one group VIII metal, comprising at least one sulfurization step and at least one passivation step using ammonia.
摘要:
The present invention concerns a process for pretreating a catalyst used in hydrocarbon conversion processes, comprising the following steps: a) pretreating a catalyst containing at least one zeolite with structure type EUO and at least one hydrodehydrogenating metal in the presence of a hydrocarbon feed, at a temperature such that a catalyst comprising carbon is obtained; b) then treating the hydrocarbon feed and the catalyst at a temperature which is lower than the temperature applied in step a). The invention also concerns an activated catalyst and its use in a process for isomerizing aromatic compounds containing 8 carbon atoms.
摘要:
A process for isomerising aromatic compounds containing eight carbon atoms is described in which the catalyst used contains at least one zeolite with structure type EUO and a group VIII element. In FIG. 1, the feed to be isomerised is introduced into reactor R via line 1. This fresh feed is enriched via lines 6 and 11 with a mixture containing at least one compound selected from the group formed by paraffins containing eight carbon atoms, benzene, toluene and naphthenes containing eight carbon atoms. Hydrogen is added via line 15.
摘要:
A process for synthesising a zeolite with structure type EUO comprising at least one element X selected from silicon and germanium and at least one element T selected from aluminum, iron, gallium, boron, titanium, vanadium, zirconium, molybdenum, arsenic, antimony, chromium and manganese, comprises reacting an aqueous mixture comprising at least one source of at least one element X, at least one source of at least one element T, and at least one precursor of an organic compound comprising at least one alkylated polymethylene &agr;-&ohgr; diammonium derivative, wherein at least one precursor is selected from monoamines. The zeolite obtained is used as a catalyst in a process for converting hydrocarbon-containing feeds, as an adsorbent to control pollution and as a molecular sieve for separation, and particularly for isomerising aromatic compounds containing 8 carbon atoms.
摘要:
The invention concerns a zeolite with structure type EUO comprising EUO zeolite crystals with a size of less than 5 &mgr;m, at least a portion of the EUO zeolite crystals being in the form of EUO zeolite aggregates, characterized in that the granulometry of the aggregates is such that Dv,90 is 500 &mgr;m or less. The invention also concerns the preparation of the zeolite and the use of the zeolite as a catalyst, for example in a process for isomerising aromatic compounds containing 8 carbon atoms per molecule.
摘要:
A process for the production of paraxilene comprises an adsorption stage (18) using toluene as a desorbent in a simulated moving bed of a feedstock previously depleted in ethylbenzene by distillation (3) or by adsortion, an isomerization stage (26) without hydrogen in liquid phase diluted with toluene from the raffinate produced, a distillation stage (27) of the raffinate that is isomerized to recover the toluene (29) that is recycled. The separated isomerate is introduced into a xylene distillation column (9). The separated ethylbenzene is isomerized separately in gas phase with hydrogen at higher temperature and is distilled (5, 2, 9) in the presence of a catalyst that comprises an EUO-structural-type zeolite, then recycled to adsorption stage (18).