Separator, reactor, and process for producing aromatic carboxylic acid

A separation system comprising:

• a distillation column into which a mixture of a first component mainly comprising water and a second component mainly comprising nonaqueous substances is supplied;
• a first separator including a first separation membrane for separating overhead vapor discharged from a top of said distillation column into a first permeable vapor which mainly comprises said first component and a first nonpermeable vapor which mainly comprises said second component by allowing only a selected portion of said overhead vapor to permeate said first separation membrane;
• and
• a second separator including a second separation membrane for separating said first permeable vapor into a second permeable vapor which mainly comprises said first component and is higher in the concentration of said first component than said first permeable vapor, and a second nonpermeable vapor which mainly comprises said second component, by allowing only a selected portion of said first permeable vapor to permeate said second separation membrane.

A reactor system comprising:

• a reactor for producing an aromatic carboxylic acid and water from an alkyl aromatic compound in a solvent containing acetic acid, and for generating a vapor mixture of a solvent and water;
• a first separation membrane for separating said vapor mixture, which is discharged from said reactor, into a first permeable vapor mainly comprising a first component and a first nonpermeable vapor mainly comprising a second component;
• a second separation membrane for separating said first permeable vapor, which is discharged from said first separation membrane, into a second permeable vapor mainly comprising the first component and a second nonpermeable vapor mainly comprising the second component;
• and
• a return passage for condensing said first nonpermeable vapor and said second nonpermeable vapor and returning the thus condensed first and second nonpermeable vapor into said reactor.