Integrated process for aromatics production

A process for producing benzene and para-xylene from a naphtha feedstock comprising the steps of:

• (a) providing a naphtha feed feedstock stream to a hydrotreating zone, wherein the feedstock is contacted with a hydrotreating catalyst under hydrotreating conditions to produce a hydrotreated naphtha stream;
• and
• (b) passing the hydrotreated naphtha stream to a reforming zone, wherein said hydrotreated naphtha is contacted with a reforming catalyst under reforming conditions to produce a reformate stream comprising aromatic components and light-end hydrocarbons;
• (c) separating all of the reformate stream, a transalkylation product stream, and an isomerization product stream, in individual streams or a combined stream, in a transalkylation stripper zone to produce a toluene and lighter hydrocarbons enriched stream and a xylene and heavier hydrocarbons enriched stream;
• (d) passing the toluene and lighter hydrocarbons enriched stream to an extractive-distillation zone to produce a raffinate stream, a stream containing C7-C8 aliphatic hydrocarbons, and a benzene and toluene enriched stream;
• (e) separating the benzene and toluene enriched stream in a fractionation column to produce a benzene-enriched stream and a toluene-enriched stream;
• (f) separating the xylene and heavier hydrocarbons enriched stream of step (c) in a xylene fractionation zone to produce a xylene-enriched stream and a stream rich in C9 and C10 alkylaromatic hydrocarbons;
• (g) passing the toluene-enriched stream and the stream rich in C9 and C10 alkylaromatic hydrocarbons, or a combined stream thereof, to a transalkylation zone, wherein said streams are contacted with a metal-stabilized transalkylation catalyst under transalkylation conditions to produce the transalkylation product stream of step (c);
• (h) passing the xylene-enriched stream to a para-xylene separation zone, wherein para-xylene is concentrated into a para-xylene enriched product stream and a para-xylene separation zone effluent stream;
• and
• (i) passing the para-xylene separation zone effluent stream to a xylenes isomerization zone wherein said stream is contacted with an isomerization catalyst under isomerization conditions to produce the isomerization product stream of step (c).

A process for isomerizing xylenes comprising:

• (a) providing a naphtha stream to a hydrotreating zone, wherein the naphtha stream is contacted with a hydrotreating catalyst under hydrotreating conditions to produce a hydrotreated naphtha stream;
• (b) passing the hydrotreated naphtha stream to a reforming zone, wherein said hydrotreated naphtha is contacted with a reforming catalyst under reforming conditions to produce a reformate stream comprising aromatic components and light-end hydrocarbons;
• (c) introducing all of the reformate stream, a transalkylation product stream, and an isomerization zone effluent, in individual streams or a combined stream, to a transalkylation stripper zone and separating a toluene and lighter hydrocarbons enriched stream and a xylene and heavier hydrocarbons enriched stream;
• and
• (d) removing light ends and LPG from the toluene and lighter hydrocarbon enriched stream to form a feed stream comprising benzene, toluene, and C5-C8 aliphatic hydrocarbons;
• (e) introducing the feed stream comprising benzene, toluene, and C5-C8 aliphatic hydrocarbons into an extractive distillation zone to separate a bottoms aromatic hydrocarbons stream comprising benzene and toluene, and an overhead aliphatic hydrocarbons stream comprising C5-C8 aliphatic hydrocarbons;
• (f) treating the overhead aliphatic hydrocarbons stream comprising C5-C8 aliphatic hydrocarbons to generate a substantially solvent-free aliphatic hydrocarbons stream;
• (g) separating the substantially solvent-free aliphatic hydrocarbons stream into a C5-C7 aliphatic hydrocarbon stream and a C7-C8 aliphatic hydrocarbon stream;
• (h) introducing the C7-C8 aliphatic hydrocarbons, hydrogen, and a non-equilibrium xylene stream comprising a non-equilibrium mixture of xylenes into an isomerization zone to contact an isomerization catalyst at isomerization conditions and generate an isomerization zone effluent.