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US 10,703,691 B1Granted
Process for producing para-xylene using two feed raffinate column
AssigneeUop LLC
InventorsAnton Mlinar, Nikunj Patel, Jason L. Noe
Life of this patent
Estimating the term…
Abstract
Process for producing para-xylene are described. The processes utilize a dual raffinate approach. Two raffinate streams from the adsorption separation unit are fed to the raffinate distillation column independently to take advantage of the differing desorbent concentrations in the two raffinate streams. The process yields significant reboiler duty savings and a reduction in overall fired fuel needed.
Claims20
A process for producing para-xylene comprising:
- separating a mixture of C8 aromatic isomers in a simulated moving bed apparatus using a desorbent to produce a para-xylene-rich extract stream, a desorbent-rich raffinate stream, and a desorbent-lean raffinate stream, wherein a concentration of desorbent in the desorbent-rich raffinate stream is greater than a concentration of desorbent in the desorbent-lean raffinate stream;
- introducing the desorbent-rich raffinate stream and the desorbent-lean raffinate stream into a fractional distillation column having a C8 aromatic outlet and a desorbent outlet, wherein the desorbent-rich raffinate stream is introduced at a first feed tray and wherein the desorbent-lean raffinate stream is introduced at a second feed tray, and wherein the first feed tray is closer to the desorbent outlet than the second feed tray;
- and
- separating the desorbent-rich raffinate stream and the desorbent-lean raffinate stream in the fractional distillation column into a C8 aromatic stream and a desorbent stream.
1 more element
A process for producing para-xylene comprising:
- separating a mixture of C8 aromatic isomers in a simulated moving bed apparatus using a desorbent to produce a para-xylene-rich extract stream, a desorbent-rich raffinate stream, and a desorbent-lean raffinate stream, wherein a concentration of desorbent in the desorbent-rich raffinate stream is greater than a concentration of desorbent in the desorbent-lean raffinate stream;
- introducing the desorbent-rich raffinate stream and the desorbent-lean raffinate stream directly into a fractional distillation column having a C8 aromatic outlet and a desorbent outlet, wherein the desorbent-rich raffinate stream is introduced at a first feed tray and wherein the desorbent-lean raffinate stream is introduced at a second feed tray, and wherein the first feed tray is closer to the desorbent outlet than the second feed tray;
- separating the desorbent-rich raffinate stream and the desorbent-lean raffinate stream in the fractional distillation column into an aromatic stream and a desorbent stream;
- introducing Whelk C8 aromatic stream from the fractional distillation column into an isomerization zone;
- isomerizing the C8 aromatic stream to form an isomerized C8 aromatic stream;
- and
- recycling the isomerized C8 aromatic stream to the simulated moving bed apparatus and wherein the isomerized C8 aromatic stream comprises at least a portion of the mixture C8 aromatic isomers.
4 more elements
Dependencies are inferred from the claim text.