Xylene separation process
AssigneesExxonMobil Chemical Patents Inc., Georgia Tech Research Corporation
InventorsJohn D. Ou, Jeevan S. Abichandani, Yoshiaki Kawajiri, Siwei Guo
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Abstract
A process is described for separating paraxylene from a multicomponent fluid mixture of C8 aromatics. A mixture of C8 aromatics is fed to a simulated moving-bed adsorptive apparatus. The location of the feed to the apparatus is moved at set intervals. The rate of flow of feed to the apparatus is varied during each interval to enhance the separation of paraxylene from the multicomponent mixture.
Claims24
A process for separating at least one C8 aromatic from a mixture of at least two C8 aromatics by simulated moving-bed adsorptive separation, said process comprising the steps of:
- (a) introducing a feed stream, which comprises at least two C8 aromatics, into a simulated moving-bed adsorptive apparatus, wherein said simulated moving-bed adsorptive apparatus comprises multiple beds containing adsorbent material;
- (b) introducing a desorbent stream, which comprises desorbent, into the simulated moving-bed adsorptive apparatus;
- (c) withdrawing an extract stream, which comprises desorbent and at least one C8 aromatic, from the simulated moving-bed adsorptive apparatus;
- (d) withdrawing at least one raffinate stream, which comprises at least one C8 aromatic, which is different from the C8 aromatic in the extract stream of step (c), from the simulated moving-bed adsorptive apparatus;
- (e) maintaining a flow of circulating fluid throughout the simulated moving-bed adsorptive apparatus;
- and
- (f) switching the flow of streams into and out of the simulated moving-bed adsorptive apparatus to a bed downstream in terms of the direction of the circulating fluid at set time interval X,
- wherein the rate flow of feed introduced in step (a) is varied during time interval X.
A process for separating at least one C8 aromatic from a mixture of at least two C8 aromatics by simulated moving-bed adsorptive separation, said process comprising the steps of:
- (a) introducing a feed stream, which comprises at least two C8 aromatics, into a simulated moving-bed adsorptive apparatus, wherein said simulated moving-bed adsorptive apparatus comprises multiple beds containing adsorbent material;
- (b) introducing a desorbent stream, which comprises desorbent, into the simulated moving-bed adsorptive apparatus;
- (c) withdrawing an extract stream, which comprises desorbent and at least one C8 aromatic, from the simulated moving-bed adsorptive apparatus;
- (d) withdrawing at least one raffinate stream, which comprises at least one C8 aromatic, which is different from the C8 aromatic in the extract stream of step (c), from the simulated moving-bed adsorptive apparatus;
- (e) maintaining a flow of circulating fluid throughout the simulated moving-bed adsorptive apparatus;
- and
- (f) switching the flow of streams into and out of the simulated moving-bed adsorptive apparatus to a bed downstream in terms of the direction of the circulating fluid at set time interval X,
- wherein the rate flow of at least one of feed introduced in step (a), extract withdrawn in step (C), and raffinate withdrawn in step (d) is varied during time interval X.
Dependencies are inferred from the claim text.