METHODS AND SYSTEMS FOR REMOVING ETHYLBENZENE FROM A MIXED XYLENE STREAM AND OPTIMIZING PARA-XYLENE SEPARATION

摘要

A method for producing enriched mixed xylenes from an unextracted mixture rich in C8 aromatics, the method comprising the steps of: starting with a feed stream including para-xylene, meta-xylene, ortho-xylene, ethylbenzene and non-aromatic compunds; converting the ethylbenzene to benzene using a chosen isomerization catalyst and removing the converted benzene from the stream while also causing a high level conversion of non-aromatic compounds to lighter hydrocarbons and removing the lighter hydrocarbons from the stream to produce the mixed xylene stream which is enriched by virtue of the elimination of ethylbenzene therefrom; and method for producing at least one chosen xylene isomer product from a feed stream including orthoxylene, meta-xylene, ethylbenzene and para-xylene, the method comprising the steps of: starting with a feed stream including para-xylene, meta-xylene, ortho-xylene and ethylbenzene; feeding the feed stream into a pretreatment unit having a chosen isomerization catalyst 3482 כ" ו בכסלו התשס" ג - December 1, 2002 therein in an amount sufficient to cause a high level conversion of ethylbenzene to benzene and removing the converted benzene from the stream; passing the remaining stream of xylenes to an isomer specific separator; removing the desired isomer from the stream; passing the remaining stream through an isomerization unit having an isomeric catalyst therein; creating a predefined equilibrium amount of xylene isomers in the isomerization unit; and passing the equilibrium stream back into the isomer specific separator for processing; and a method for producing enriched mixed xylenes from an unextracted mixture rich in C8 aromatics, the method comprising the steps of: starting with a feed stream including para-xylene, meta-xylene, ortho-xylene, ethylbenzene and non-aromatic compounds; feeding the feed stream into a pretreatment unit having a chosen isomerization catalyst therein in an amount sufficient to cause a chosen level conversion of ethylbenzene to benzene and removing the converted benzene from the stream; and concurrently causing a high level conversion of non- aromatic compounds to lighter hydrocarbons within the pretreatment unit and removing the lighter hydrocarbons from the stream, the stream being enriched by virture of the removal of ethylbenzene and non-aromatic compounds from the stream; and a method for producing at least one chosen xylene isomer product from a feed stream including ortho-xylene, meta-xylene, ethylbenzene, para-xylene, and non- aromatics, the method comprising the steps of: starting with a feed stream including para-xylene, meta-xylene, ortho-xylene, ethylbenzene and non-aromatics; passing the feed stream through an isomerization unit having an isomerization catalyst therein and having unit specific operating parameters of temperature, liquid hourly space velocity, hydrogen partial pressure and/or catalyst amount calculated and set to maximize ethylbenzene and non-aromatic conversion; converting ethylbenzene to benzene and non-aromatics to light petroleum gases and removing the converted benzene and light petroleum gases from the stream while creating a predefined equilibrium effluent of xylene isomers in the isomerization unit; passing the effluent into an isomer specific separator; extracting the desired isomer product; and passing a raffinate of remaining xylene isomers back to the isomerization unit; and method for producing at least one chosen xylene isomer product from a feed stream including ortho-xylene, meta-xylene, ethylbenzene and para-xylene, the method comprising the steps of: starting with a feed stream including para-xylene, meta-xylene, ortho-xylene and ethylbenzene; passing the feed stream through a pretreatment reactor having a chosen isomerization catalyst therein in an amount sufficient to cause a high level conversion of ethylbenzene to benzene and removing the converted benzene from the stream, creating an enriched mixed xylene feed stream; passing the feed and raffinate through an isomerization unit having an iosmeric catalyst therein to produce an effluent having an optimized predefined equilibrium concentration of xylene isomers therein; passing the effluent into an isomer specific separator for processing; extracting the desired isomer from the effluent; and passing a raffinate of remaining xylenes back to the isomerization unit. 3483 כ" ו בכסלו התשס" ג - December 1, 2002