Patent ID: 8569559
Filing Date: 2013-10-29
Classification: B01D,B01J,C07C,Y02P

Abstract:
1. A process for the production of paraxylene comprising: (i) providing a first feedstream, containing xylenes including paraxylene (PX) and non-xylenes, to a xylenes separator to produce a xylenes-rich second stream characterized by an increased concentration of xylenes, relative to said first feedstream, and a xylenes-lean third stream characterized by a decreased concentration of xylenes, relative to said first feedstream; (ii) passing said second stream to a first paraxylene separation step whereby paraxylene is separated from orthoxylene (OX) and metaxylene (MX) to produce a fourth stream characterized by an increased concentration of paraxylene, relative to said second stream, and a fifth stream characterized by a decreased concentration of paraxylene, relative to said second stream; (iii) passing said fourth stream to a second paraxylene separation step whereby paraxylene is separated from orthoxylene, and metaxylene, to produce a sixth stream characterized by an increased concentration of paraxylene relative to the concentration of paraxylene in said fourth stream, and a seventh stream characterized by a decreased concentration of paraxylene relative to the concentration of paraxylene in said fourth stream; (iv) passing said fifth stream to a liquid phase isomerization step whereby orthoxylene and metaxylene are isomerized to produce an eighth stream characterized by an increased concentration of paraxylene, relative to the concentration of paraxylene in said fifth stream; (v) passing at least a portion of said eighth stream to said xylenes separator (step (i)); (vi) passing said seventh stream to a vapor phase isomerization step whereby orthoxylene and metaxylene are isomerized to produce a ninth stream characterized by an increased concentration of paraxylene relative to the concentration of paraxylene in said seventh stream; (vii) passing said ninth stream to said xylenes separator (step (i)) wherein said first paraxylene separation step (step ii) is selected from at least one of adsorptive separation, crystallization separation, and membrane separation.