US3960520A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Separation of isomers
Assignee: Mobil Oil AS
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Filing: 1975-03-19
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Granted: 1976-06-01
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Expires: 1995-03-19
Abstract
Abstract A mixture of C8 aromatics, including para-xylene, meta-xylene orthoxylene and ethyl benzene, is separated by an adsorption/desorption procedure to provide rapid recovery of the valuable components. In this process, the aromatic mixture is passed through at least two adsorption zones in series, preferably containing zeolite ZSM-5 adsorbent, in which zones the meta-xylene and ortho-xylene pass through relatively uninhibited, whereas the para-xylene and ethyl benzene are adsorbed. The meta-xylene and ortho-xylene are removed and can be distilled to effect separation or can be separated as described in U.S. Pat. No. 3,656,278. According to this invention, the para-xylene and ethyl benzene in the zones are then desorbed in parallel, that is, introducing a desorbent separately to each zone and recovering desorbed aromatics separately from each.
Inventors
- 👤 Paul T. Allen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:25
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/02; B01D53/04; B01D53/0407; B01D53/0423; C; C07; C07C; C07C7/00; C07C7/12; C07C7/13; B01D2253/00; B01D2253/10; B01D2253/106; B01D2253/108; B01D2256/00; B01D2256/24; B01D2257/00; B01D2257/70; B01D2257/702; B01D2257/7027; B01D2259/00; B01D2259/40; B01D2259/40083; B01D2259/40088; B01D2259/4009; B01D2259/404; B01D2259/41
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
126 words
In a method for the separation and recovery of the isomers contained in an aromatic mixture comprising para-xylene, meta-xylene, ortho-xylene and ethyl-benzene to separate this mixture into one stream comprising meta-xylene and ortho-xylene and a second stream comprising para-xylene and ethyl benzene, by a process which includes conducting said mixture through an elongated bed of zeolite adsorbent contained in a column whereby paraxylene and ethyl benzene are substantially adsorbed and meta-xylene and ortho-xylene are substantially not adsorbed, the improvement which comprises contacting said mixture in vapor phase with said zeolite adsorbent to effect adsorption of at least a major amount of the para-xylene and ethyl benzene and separately desorbing the adsorbed para-xylene and ethyl benzene simultaneously from each of a plurality of portions of said bed.
Claim 2
Dependent Claim
126 words
In a method for the separation and recovery of the isomers contained in an aromatic mixture comprising para-xylene, meta-xylene, ortho-xylene and ethyl-benzene to separate this mixture into one stream comprising meta-xylene and ortho-xylene and a second stream comprising para-xylene and ethyl benzene, by a process which includes conducting said mixture through an elongated bed of zeolite adsorbent contained in a column whereby paraxylene and ethyl benzene are substantially adsorbed and meta-xylene and ortho-xylene are substantially not adsorbed, the improvement which comprises contacting said mixture in vapor phase with said zeolite adsorbent to effect adsorption of at least a major amount of the para-xylene and ethyl benzene and separately desorbing the adsorbed para-xylene and ethyl benzene simultaneously from each of a plurality of portions of said bed.
Claim 3
Dependent Claim
35 words
A method according to claim 1 wherein said starting aromatic mixture contains about 15-40 weight percent of para-xylene, about 0-15 weight percent ethyl benzene, about 0-25 weight percent ortho-xylene and about 40-60 weight percent meta-xylene.
Claim 4
Dependent Claim
27 words
A method according to claim 2 wherein said adsorption stage is conducted in the presence of the zeolite adsorber at a temperature of about 50° to 500°F.
Claim 5
Dependent Claim
15 words
A method according to claim 3 wherein the adsorbent is zeolite ZSM-5 or zeolite ZSM-11.
Claim 6
Dependent Claim
11 words
A method according to claim 4 wherein the desorbent is steam.
Claim 7
Dependent Claim
72 words
A method according to claim 1 wherein the desorbent is introduced as a first stream at one end of the bed and as a second stream at one point intermediate the ends of the bed, the first desorbent stream being removed at a point intermediate the ends of the bed and the second stream at the end of the column bed remote from the end at which said first stream is introduced.
Claim 8
Dependent Claim
37 words
A method according to claim 6 wherein desorbent is introduced at one end of the bed and at least two points along the length of the column and separate exit points are provided for each desorbent stream.
Claim 9
Dependent Claim
34 words
A method according to claim 5 wherein the desorbent stream is processed to remove the desorbent gas which is recycled to the system and there is removed a mixture of para-xylene and ethyl benzene.
Claim 10
Dependent Claim
29 words
A method according to claim 1 wherein streams of para-xylene mixed with ethyl benzene desorbed from different portions of the bed are resolved into their components by chromatographic separation.
Claim 11
Dependent Claim
19 words
A method according to claim 9 wherein the sorbent in said chromatographic separation in zeolite ZSM-5 or zeolite ZSM-11.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-01 | 1979-12-01 | 1980-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-01 | 1983-12-01 | 1984-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-01 | 1987-12-01 | 1988-06-01 | $7700.00 | Window Closed / Lapsed |