Abstract: A method for recovering paraxylene from a mixture of aromatic hydrocarbons. The process uses a pressure swing adsorption zone followed by a paraxylene recovery zone. The invention provides for lower throughput through the paraxylene recovery zone, resulting in lower capital costs and operating costs.

Abstract: A method for the recovery paraxylene with reduced crystallization. Paraxylene is recovered from a mixture of C8 aromatic hydrocarbons in a pressure swing adsorption zone and a crystallization zone. The invention provides for lower throughput through the crystallization zone, resulting in lower capital costs, reduced electricity in operating separation equipment, as well as reduced refrigeration duty.

Abstract: A method for the recovery paraxylene with reduced crystallization. Paraxylene is recovered from a mixture of C8 aromatic hydrocarbons in a pressure swing adsorption zone and a crystallization zone. The invention provides for lower throughput through the crystallization zone, resulting in lower capital costs, reduced electricity in operating separation equipment, as well as reduced refrigeration duty.

Abstract: A method for recovering paraxylene from a mixture of aromatic hydrocarbons. The process uses a pressure swing adsorption zone followed by a paraxylene recovery zone. The invention provides for lower throughput through the paraxylene recovery zone, resulting in lower capital costs and operating costs.

Abstract: A method for retrofitting a system for recovering paraxylene. The system is retrofitted with a pressure swing adsorption unit and a second isomerization reactor. The retrofit lowers the variable cost of the plant, while providing the opportunity to maintain existing equipment and furnace and refrigeration duty.

Abstract: 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.

Abstract: A method of recovering paraxylene in a crystallization zone. The crystallization zone includes at least two crystallization stages and two reslurry stages. The method provides for lower throughput through the crystallization zone, resulting in lower capital costs, reduced electricity in operating separation equipment, as well as reduced refrigeration duty.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A method for retrofitting a system for recovering paraxylene. The system is retrofitted with a pressure swing adsorption unit and a second isomerization reactor. The retrofit lowers the variable cost of the plant, while providing the opportunity to maintain existing equipment and furnace and refrigeration duty.

Abstract: A method of recovering paraxylene in a crystallization zone. The crystallization zone includes at least two crystallization stages and two reslurry stages. The method provides for lower throughput through the crystallization zone, resulting in lower capital costs, reduced electricity in operating separation equipment, as well as reduced refrigeration duty.