Method of production of paraxylene comprising a step of adsorption, a stage of isomerization in the liquid phase and a stage of isomerization of the gaseous phase with a zeolite of type eu0

摘要

Para-xylene production comprises an bed-adsorption phase simulating a charge or 8 aromatic carbon atoms and an ethyl benzene isomerization step in liquid phase of a fraction poor in para-xylene recovered from the bed. Para-xylene production comprises: (1) enriching a charge or 8C hydrocarbons comprising o-, m- and p-xylene and ethyl benzene in an enriching zone; (2) recovering a first fraction mainly containing ethyl benzene; (3) isolating this fraction in a gas phase catalytic isomerization zone containing H2 and catalyst; (4) recovering an isomer and distilling it in a column to eliminate light fractions; (5) recycling the residual isomerate in an enriching zone to give a second fraction; (6) distilling this fraction in a second column; (7) recovering a distillate containing o-, m- and p-xylene and a reduced amount of ethyl benzene; (8) recycling in an adsorption column and adsorbing on a bed containing zeolite catalyst in the presence of an adsorber; (9) recovering a first fraction rich in p-xylene and a second fraction poor in p-xylene an containing adsorber, m-xylene, o-xylene and ethyl benzene in an amount of at least 15 wt.% of the adsorber; either (10) isomerizing the second fraction in liquid phase in a second catalytic isomerization zone, distilling and recovering an isomerizate without adsorber; or (11) distilling the second fraction in a distillation column and tapping a fraction containing m-xylene and adsorber, isomerizing at least part of this fraction in liquid phase in a catalytic isomerization zone, introducing the isomerized fraction in the same distillation column as in (10) or recycling part of it to the introduction point to wash it and recovering an isomerizate free of adsorber, then recycling it in the adsorption column. The catalyst in the gas phase isomerization zone is an EU0 type zeolite.