A method of recovering paraxylene in a pressure swing adsorption unit with varying hydrogen purge pressures. The pressure swing adsorption zone is adapted to adsorb and desorb paraxylene based on the cycling of partial pressure in the zone. A first hydrogen purge is fed concurrent to the feed. A second hydrogen purge is countercurrent to the feed.

A method of recovering paraxyiene in a pressure swing adsorption unit with varying hydrogen purge pressures. The pressure swing adsorption zone is adapted to adsorb and desorb paraxyiene based on the cycling of partial pressure in the zone. A first hydrogen purge fed to the zone is within 50 psi of the adsorption pressure of paraxyiene in the zone. A second hydrogen purge fed to the zone is within 50 psi of the desorption pressure of paraxyiene in the zone. The overall amount of hydrogen necessary to operate the pressure swing adsorption zone is reduced and heat may be recovered from the effluent leaving the pressure swing adsorption zone.

A method of recovering paraxyiene in a pressure swing adsorption unit with varying hydrogen purge pressures. The pressure swing adsorption zone is adapted to adsorb and desorb paraxyiene based on the cycling of partial pressure in the zone. A first hydrogen purge fed to the zone is within 50 psi of the adsorption pressure of paraxyiene in the zone. A second hydrogen purge fed to the zone is within 50 psi of the desorption pressure of paraxyiene in the zone. The overall amount of hydrogen necessary to operate the pressure swing adsorption zone is reduced and heat may be recovered from the effluent leaving the pressure swing adsorption zone.

A process for the treatment of a light naphtha feedstock that comprises normal paraffins and iso-paraffins may include separating the feedstock into a first iso-paraffin stream and a normal paraffin stream. The separating may be performed with 5 A molecular sieves, a pressure of about 1-3 bars, and a temperature of 100-260° C. A product stream may be provided by subjecting the normal paraffin stream to at least one of steam cracking, isomerizing, and aromatizing.

A process for the treatment of a light naphtha feedstock that comprises normal paraffins and iso-paraffins may include separating the feedstock into a first iso-paraffin stream and a normal paraffin stream. The separating may be performed with 5 A molecular sieves, a pressure of about 1-3 bars, and a temperature of 100-260° C. A product stream may be provided by subjecting the normal paraffin stream to at least one of steam cracking, isomerizing, and aromatizing.

A method for producing para-xylene (PX) includes introducing a C.sub.8 aromatic-containing composition to a xylene rerun column to separate the C.sub.8 aromatic-containing composition into a xylene-containing effluent and a heavy effluent and passing the xylene-containing effluent to a PX processing loop that includes a PX recovery unit operable to separate a PX product from the xylene-containing effluent, a membrane isomerization unit operable to convert a portion of the MX, OX, or both from the xylene-containing effluent to PX, an EB dealkylation unit operable to dealkylate EB from the xylene-containing effluent to produce benzene, toluene, and other C.sub.7− compounds, and a membrane separation unit operable to produce a permeate that is PX-rich and a retentate that is PX-lean. The permeate is passed to the PX recovery unit for recovery of PX, which the retentate is bypassed around the PX recovery unit circulated through the xylene processing loop.

A method for producing para-xylene (PX) includes introducing a C.sub.8 aromatic-containing composition to a xylene rerun column to separate the C.sub.8 aromatic-containing composition into a xylene-containing effluent and a heavy effluent and passing the xylene-containing effluent to a PX processing loop that includes a PX recovery unit operable to separate a PX product from the xylene-containing effluent, a membrane isomerization unit operable to convert a portion of the MX, OX, or both from the xylene-containing effluent to PX, an EB dealkylation unit operable to dealkylate EB from the xylene-containing effluent to produce benzene, toluene, and other C.sub.7− compounds, and a membrane separation unit operable to produce a permeate that is PX-rich and a retentate that is PX-lean. The permeate is passed to the PX recovery unit for recovery of PX, which the retentate is bypassed around the PX recovery unit circulated through the xylene processing loop.

Methods of producing an isomerization catalyst include preparing a catalyst precursor solution, hydrothermally treating the catalyst precursor solution to produce a magnesium oxide precipitant, and calcining the magnesium oxide precipitant to produce the isomerization catalyst. The catalyst precursor solution includes at least a magnesium precursor, a hydrolyzing agent, and cetrimonium bromide. Methods of producing 1-butene from a 2-butene-containing feedstock with the isomerization catalyst are also disclosed.

A process for the treatment of a light naphtha feedstock that comprises normal paraffins and iso-paraffins may include separating the feedstock into a first iso-paraffin stream and a normal paraffin stream. The separating may be performed with 5A molecular sieves, a pressure of about 1-3 bars, and a temperature of 100-260° C. A product stream may be provided by subjecting the normal paraffin stream to at least one of steam cracking, isomerizing, and aromatizing.

A process for the treatment of a light naphtha feedstock that comprises normal paraffins and iso-paraffins may include separating the feedstock into a first iso-paraffin stream and a normal paraffin stream. The separating may be performed with 5A molecular sieves, a pressure of about 1-3 bars, and a temperature of 100-260° C. A product stream may be provided by subjecting the normal paraffin stream to at least one of steam cracking, isomerizing, and aromatizing.