Process for npentanizing debutanized natural gasoline feedstock to thermal crackers

Patent metadata

Field	Value
Publication number	US-10995283-B2
Application number	US-201816497908-A
Country	US
Kind code	B2
Filing date	Mar 29, 2018
Priority date	Apr 3, 2017
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

A process for producing natural gasoline. The process includes increasing the n-pentane concentration of debutanized natural gasoline. The process may include a first concentration process that includes distillation and a second concentration process that includes simulated moving bed adsorption.

First claim

The invention claimed is:

1. A method of increasing n-pentane concentration in debutanized natural gasoline, the method comprising:
splitting a stream, comprising primarily n-pentane and isopentane collectively, into a first feed stream comprising primarily n-pentane and isopentane collectively and a second feed stream comprising primarily n-pentane and isopentane collectively;
subjecting the first feed stream to a first concentrating process, the first concentrating process comprises distilling and produces a first product stream comprising primarily n-pentane and a second product stream comprising methane, ethane, and propane; and
subjecting the second feed stream to a second concentrating process, the second concentrating process comprises simulated moving bed adsorbing to produce a third product stream comprising primarily n-pentane and a fourth product stream comprising primarily isopentane;

wherein the first feed stream and/or the second feed stream comprises 85 mol. % to 95 mol. % n-pentane and isopentane collectively.

2. The method of claim 1 , wherein the first concentrating process comprises:
distilling a combined stream that comprises a mixture of the first feed stream and a recycle stream having primarily isopentane to produce a bottoms stream comprising primarily n-hexane, an intermediate stream comprising primarily n-pentane, and an overhead stream comprising primarily isopentane;
combining the intermediate stream and the bottoms stream to produce the first product stream;
isomerizing the overhead stream in a reactor to convert at least some of the overhead stream's isopentane to n-pentane; and
distilling effluent from the reactor to form the recycle stream and the second product stream.

3. The method of claim 2 , wherein the isomerizing includes mixing the overhead stream with hydrogen to form a mixture and contacting the mixture with a catalyst under reaction conditions to isomerize at least some of the isopentane to n-pentane.

4. The method of claim 3 , wherein the catalyst does not include zeolite and is a selection from the list consisting of: sulfated zirconia, platinum on alumina, platinum on alumina dosed with perchloroethylene or other chlorinating agent, flouridized catalyst, and combinations thereof.

5. The method of claim 3 , wherein the reaction conditions include a reaction temperature of 130 to 276° C., a pressure of 15 to 30 bar and GHSV of 4 to 5.5.

6. The method of claim 4 , wherein the catalyst is platinum on alumina dosed with perchloroethylene.

7. The method of claim 4 , wherein the catalyst is a flouridized catalyst.

8. The method of claim 1 , wherein the catalyst does not contain a zeolite.

9. The method of claim 1 , wherein the first feed stream and/or the second feed stream further comprises cypentane, cis pentene, and n-hexane.

10. The method of claim 1 , wherein the second product stream further comprises n-butane and isobutane.

11. The method of claim 1 , wherein the overhead stream comprises 82 mol. % to 92 mol. % isopentane and 6 mol. % to 16 mol. % neopentane.

12. The method of claim 1 , wherein the intermediate stream comprises 96 mol. % to 100 mol. % n-pentane.

13. The method of claim 1 , wherein the bottoms stream comprises 55 mol. % to 65 mol. % n-hexane and 35 mol. % to 45 mol. % cypentane.

14. A method of increasing n-pentane concentration in debutanized natural gasoline, the method comprising:
splitting a stream, comprising primarily n-pentane and isopentane collectively, into a first feed stream comprising primarily n-pentane and isopentane collectively and a second feed stream comprising primarily n-pentane and isopentane collectively;
subjecting the first feed stream to a first concentrating process, the first concentrating process comprises distilling and produces a first product stream comprising primarily n-pentane and a second product stream comprising methane, ethane, and propane; and
subjecting the second feed stream to a second concentrating process, the second concentrating process comprises simulated moving bed adsorbing to produce a third product stream comprising primarily n-pentane and a fourth product stream comprising primarily isopentane, wherein the second concentrating process comprises:

feeding the second feed stream at a first port in a series of adsorbent columns;
feeding an eluent at a second port in the series of adsorbent columns;
removing raffinate from a third port in the series of adsorbent columns; removing extract from a fourth port in the series of adsorbent columns; and
simulating switching location of the first port, second port, third port, and fourth port repeatedly amongst each other.

15. The method of claim 14 , wherein the third product stream comprises 70 to 95 mol. % n-pentane.

16. The method of claim 14 , wherein the ports are configured in the following order consistent with the direction of liquid flow through the columns: eluent port, extract port, feed port, and raffinate port.

17. The method of claim 14 , wherein the eluent comprises a selection from the list consisting of: n-butane, isobutane, an alkane of different molecular weight than streams being separated, and combinations thereof.

18. The method of claim 14 , wherein the raffinate comprises the third product stream and the extract comprises isopentane.

19. The method of claim 2 , wherein the effluent from the reactor comprises 58 mol. % to 69 mol. % isopentane and 15 mol. % to 25 mol. % n-pentane.

Assignees

• Sabic Global Technologies Bv

Inventors

• Bodas Vijay Dinkar
• Al-Otaibe Sultan
• Leal Guillermo
• Ansari Mohammed Bismillah

Classifications

• C07C5/2724

  with metals · CPC title

• C07C2527/053

  Sulfates or other compounds comprising the anion (SnO3n+1)2- · CPC title

• C10G2300/104

  Light gasoline having a boiling range of about 20 - 100 °C · CPC title

• C10G25/08

  according to the "moving bed" method · CPC title

• C10G61/06 Primary

  the refining step being a sorption process · CPC title