# US 2013/0158331 A1 · Process and Apparatus for para-Xylene Production using Multiple Adsorptive Separation Units and Multiple Adsorptive Bed Feed Points

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- Number: US 2013/0158331 A1
- Document ID: US20130158331A1
- Status: Published application
- Kind: A1
- Application number: 13/326,961
- Filed: 2011-12-15
- Published: 2013-06-20
- Earliest claimed: 2011-12-15
- Assignees: Uop LLC
- Inventors: Jason T. Corradi; Sara A. Williams; Stanley J. Frey
- Web page: https://patentgrep.com/patent/US20130158331A1

## CPC

- C07C 5/2729: {Changing the branching point of an open chain or the point of substitution on a ring}
- B01D 15/102: {Process control, e.g. determination or optimization of process parameters; Programmable logic control [PLC]}
- B01D 15/1828: {characterised by process features}
- C07C 7/04: by distillation
- C07C 7/12: by adsorption, i.e. purification or separation of hydrocarbons with the aid of solids, e.g. with ion-exchangers
- C07C 7/13: by molecular-sieve technique
- C10G 25/00: Refining of hydrocarbon oils in the absence of hydrogen, with solid sorbents
- C10G 25/12: Recovery of used adsorbent
- C10G 2300/4056: Retrofitting operations
- C10G 2400/30: Aromatics
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C10G: CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION (cracking to hydrogen or synthesis gas C01B; cracking or pyrolysis of hydrocarbon gases to individual hydrocarbons or mixtures thereof of definite or specified constitution C07C; cracking to cokes C10B); RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES

## Abstract

A process for separating para-xylene from aromatic compounds is presented. The process introduces throughout a first step-time interval a first mixed xylem stream into a first feed input on a first adsorptive separation unit comprising multiple bed lines. The process further introduces throughout the first step-time interval a second mixed xylene stream into a second feed input on the first adsorptive separation unit. During a first portion of the first step-time interval, the process introduces material from a feed stream used during the first step-time interval into a bed line not used to deliver a stream into, or withdraw a stream from, the first adsorptive separation unit during the first step time interval. During a second portion of the first step-time interval, the process introduces material from a purification zone into the feed stream used during the first step-time interval.

## Claims

### Claim 1

A process for separating para-xylene from a plurality of aromatic compounds, the process comprising:
introducing throughout a first step-time interval a first mixed xylene stream comprising a plurality of xylene isomers into a first feed input on a first adsorptive separation unit comprising a plurality of bed lines, wherein said first adsorptive separation unit comprises a purification zone;
introducing throughout said first step-time interval a second mixed xylene stream comprising a plurality of xylene isomers into a second feed input on said first adsorptive separation unit;
during a first portion of said first said step-time interval, introducing material from a feed stream used during said first step-time interval into a bed line riot used to deliver a stream into, or to withdraw a stream from, said first adsorptive separation unit during said first step time interval; and
during a second portion of said first said step-time interval, introducing material from said purification zone into said feed stream used during said first step-time interval.

### Claim 2 (depends on 1)

The process of claim 1, wherein said first portion of said first step-time interval differs from said second portion of said first step-time interval.

### Claim 3 (depends on 2)

The process of claim 2, wherein a flow rate of said first mixed xylene stream into said first feed input is non-uniform over said first portion of said first step-time interval.

### Claim 4 (depends on 3)

The process of claim 3, wherein a flow rate of said feed material into said second bed line is non-uniform over said second portion of said first step-time interval.

### Claim 5 (depends on 1)

The process of claim 1, further comprising:
producing a first para-xylene enriched stream and a first raffinate stream;
introducing a second mixed xylene feed stream comprising a plurality of xylene isomers into a second, adsorptive separation unit to produce a second para-xylene enriched stream and a second raffinate stream; and
feeding both said first raffinate stream and said second raffinate stream into a raffinate column.

### Claim 6 (depends on 5)

The process of claim 5, further comprising:
producing by said raffinate column a C8 raffinate stream;
introducing the C8 raffinate stream into an isomerization unit to produce the said second mixed xylene stream.

### Claim 7 (depends on 5)

The process of claim 5, wherein:
the first raffinate stream enters the raffinate column at a first location;
the C8 raffinate stream exits the raffinate column at a second location;
the second raffinate stream enters the raffinate column at a third location; and
wherein the second location is disposed between the first location and the third location.

### Claim 8 (depends on 6)

The process of claim 6, further comprising introducing said second enriched para-xylene stream into a second extract column.

### Claim 9 (depends on 8)

The process of claim 8, further comprising introducing said first enriched para-xylene stream into a first extract column,

### Claim 10 (depends on 8)

The process of claim 8, further comprising generating a xylene product stream from said second extract column without use of a finishing column.

### Claim 11

An apparatus for separating para-xylene from a plurality of aromatic compounds, comprising:
a first adsorptive separation unit comprising a rotary valve comprising more than 8 tracks, said first adsorptive unit being in fluid communication with said rotary valve and comprising a first feed input and a second feed input;
a second adsorptive separation unit; and
a raffinate column in fluid communication with both said first adsorptive separation unit and said second adsorptive separation unit.

### Claim 12 (depends on 11)

The apparatus of claim 11, further comprising:
an isomerization unit in fluid communication with both said raffinate column and said second adsorptive separation unit.

### Claim 13 (depends on 11)

The apparatus of claim 11, wherein:
said raffinate column comprises a first input, a second input, and an output;
said first adsorptive separation unit is in fluid communication with said first input; and
said second adsorptive separation unit is in fluid communication with said second input.

### Claim 14 (depends on 13)

The apparatus of claim 13, further comprising an isomerization unit in fluid communication with said output.

### Claim 15 (depends on 14)

The apparatus of claim 14, further comprising:
a first extract column in fluid communication with the first adsorptive separation unit; and
a second extract column in fluid communication with the second adsorptive separation unit.

### Claim 16 (depends on 15)

The apparatus of claim 15, further comprising a xylene fractionation unit in fluid communication with said second extract column,

### Claim 17 (depends on 16)

The apparatus of claim 16, wherein said first extract column is configured to produce a para-xylene product stream.

### Claim 18 (depends on 15)

The apparatus of claim 15, further comprising a xylene fractionation unit in fluid communication with said first adsorptive separation unit.

### Claim 19 (depends on 18)

The apparatus of claim 18, further comprising a finishing column in fluid communication with the first extract column.

### Claim 20 (depends on 11)

The apparatus of claim 11, further comprising a drag line in fluid communication with said raffinate column.