Apparatus for the separation of p-xylene in C.sub.8 aromatic hydrocarbons with a simulated moving bed adsorption and a crystallization
US5401476A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 27, 1993 |
| Grant date | Mar 28, 1995 |
| Priority date | — |
| Expiry date | Oct 27, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C7/14
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
To continuously produce and separate high purity p-xylene from a C.sub.8 aromatic hydrocarbon charge, successive use is made in combination of (1) a stage of separating low-purity p-xylene (75 to 98%) by simulated moving bed adsorption chromatography, with a ratio of the solvent to charge flow rates of 1.2 to 2.5; (2) a stage of purifying and washing the low-purity p-xylene by recrystallization (-25 to +10.degree. C.); (3) a stage of catalytic isomerization of the charge which has been p-xylene-depleted by the separating stage (1); and recovering an isomerate which is then recycled to the charge. The solvent for desorption in stage (1) and washing in stage (2) is advantageously toluene.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.