Integrated perchloroethylene decomposition reactor design for C4 and C5-6 isomerization units

Patent metadata

Field	Value
Publication number	US-11034629-B1
Application number	US-202016734471-A
Country	US
Kind code	B1
Filing date	Jan 6, 2020
Priority date	Jan 6, 2020
Publication date	Jun 15, 2021
Grant date	Jun 15, 2021

Abstract

Processes incorporating a common organic chloride decomposition reactor and chloride treater to be used by both the C 4 and C 5-6 isomerization reaction zones are described. A portion of the C 4 isomerization reaction zone off gas is routed to the C 4 HCl absorber, which provides about 85% of the HCl requirement for the C 4 isomerization reaction zone. A small amount of the C 5-6 isomerization reaction zone off gas is mixed with the C 4 isomerization reaction zone off gas portion going to the C 4 HCl absorber.

First claim

What is claimed is:

1. An integrated process for C 4 isomerization and C 5-6 isomerization comprising:
passing a C 5-6 feed stream comprising normal pentane and normal hexane to a C 5-6 HCl absorber forming a C 5-6 absorber bottoms stream comprising normal pentane, normal hexane and HCI, and a C 5-6 absorber overhead stream comprising a trace amount of HCl;
passing a first hydrogen rich gas stream and a chloride feed stream containing an organic chloride compound to an organic chloride decomposition reactor containing a chloride decomposition catalyst to decompose the organic chloride compound to form a chloride effluent stream comprising hydrogen, hydrocarbon, and HCl;
passing the C 5-6 absorber bottoms stream and the chloride effluent stream to a C 5-6 isomerization reaction zone under C 5-6 isomerization conditions in the presence of a C 5-6 isomerization catalyst to convert a portion of the normal pentane and normal hexane to iso-pentane and iso-hexane, forming a C 5-6 isomerization effluent comprising normal pentane, normal hexane, iso-pentane, iso-hexane, and gases;
separating the C 5-6 isomerization effluent in a C 5-6 stabilizer column into at least a C 5-6 product stream comprising the normal pentane, normal hexane, iso-pentane, and iso-hexane, and a C 5-6 off gas stream;
passing a C 4 feed stream comprising normal butane to a C 4 HCl absorber forming a C 4 absorber bottoms stream comprising normal butane and HCI, and a C 4 absorber overhead stream comprising a trace amount of HCl;
passing the C 4 absorber bottoms stream and a second hydrogen rich gas stream to a C 4 isomerization reaction zone under C 4 isomerization conditions in the presence of a C 4 isomerization catalyst to convert a portion of the normal butane to iso-butane forming a C 4 isomerization effluent comprising normal butane, iso-butane, and gases;
separating the C 4 isomerization effluent in a C 4 stabilizer column into at least a C 4 product stream comprising the normal butane and iso-butane, and a C 4 off gas stream;
splitting the C 5-6 off gas stream into three streams, and passing the first C 5-6 off gas stream to the C 5-6 HCl absorber, passing the second C 5-6 off gas stream to the C 4 HCl absorber, and passing the third C 5-6 off gas stream to a chloride treater, wherein the first C 5-6 off gas stream comprises about 75 to about 90% of the C 5-6 off gas stream, the second C 5-6 off gas stream comprises about 5 to about 15% of the C 5-6 off gas stream, and the third C 5-6 off gas stream comprises about 5 to about 20% of the C 5-6 off gas stream;
splitting the C 4 off gas stream into two streams, and passing the first C 4 off gas stream to the C 4 HCl absorber, and passing the second C 4 off gas stream to the C 5-6 HCl absorber, wherein the first C 4 off gas stream comprises about 75 to about 95% of the C 4 off gas stream, and the second C 4 off gas stream comprises about 5 to about 25% of the C 4 off gas stream; and
passing the C 5-6 absorber overhead stream from the C 5-6 HCl absorber and the C 4 absorber overhead stream from the C 4 HCl absorber to the chloride treaters.

2. The process of claim 1 further comprising:
determining an amount of HCl required in the C 4 HCl absorber bottoms stream; and
controlling a flow rate of the second C 5-6 off gas stream to the C 4 HCl absorber based on the determined amount of HCl required in the C 4 HCl absorber bottoms stream.

3. The process of claim 1 wherein separating the C 5-6 isomerization effluent in the C 5-6 stabilizer column into at least the C 5-6 product stream comprising the normal pentane, normal hexane, iso-pentane, and iso-hexane, and the C 5-6 off gas stream comprises separating the C 5-6 isomerization effluent in the C 5-6 stabilizer column into at least the C 5-6 product stream comprising the normal pentane, normal hexane, iso-pentane, and iso-hexane, the C 5-6 off gas stream, and a stream comprising hydrocarbons having 3 to 4 carbon atoms.

4. The process of claim 1 further comprising at least one of:
passing the C 5-6 product stream to a deisohexanizer column; or
passing the C 4 product stream to a deisobutanizer column.

5. The process of claim 1 further comprising at least one of:
drying the C 5-6 feed stream before passing the C 5-6 feed stream to the C 5-6 HCl absorber; or
drying the C 4 feed stream before passing the C 4 feed stream to the C 4 HCl absorber.

6. The process of claim 1 wherein at least one of: the C 5-6 isomerization conditions comprise one or more of: a temperature in a range of about 80° C. to about 215° C.; a pressure in a range of about 1.4 MPa(g) to about 7.0 MPa(g); or a liquid hourly space velocity in a range of about 0.5 to about 12 hr −1 ; or the C 4 isomerization conditions comprise one or more of: a temperature in a range of about 80° C. to about 215° C.; a pressure in a range of about 1.4 MPa(g) to about 7.0 MPa(g); or a liquid hourly space velocity in a range of about 4 to about 24 hr −1 .

7. The process of claim 1 wherein a hydrogen to organic chloride molar ratio in the organic chloride decomposition reactor is about 350:1 to about 2700:1.

8. The process of claim 1 wherein the chloride decomposition catalyst comprises at least one of: nickel, platinum, or palladium.

9. The process of claim 1 wherein the organic chloride compound comprises one or more of a perchloro C 1 -C 4 hydrocarbon or carbon tetrachloride.

10. The process of claim 9 wherein an amount of chloride equivalent in the chloride effluent stream can be calculated using an equation:
C*G*(1−E*F)−A*G*(1−B)*F

where: A is a C 4 feed rate; B is a ratio of an amount of the first C 4 off gas stream sent to the C 4 HCl absorber to a total amount of the C 4 off gas stream; C is a C 5-6 feed rate; E is a ratio of an amount of the first C 5-6 off gas stream to the total amount of the C 5-6 off gas stream; F is a fraction of HCl recovered from a combination of the first C 5-6 off gas stream and the second C 4 off gas stream sent to the C 5-6 HCl absorber; and G is a constant which depends on process parameters and the type of chloriding agent used.

11. The process of claim 1 wherein an amount of the second C 5-6 off gas stream can be calculated using an equation:
A*(1−B*D)/C

where: A is a C 4 feed rate; B is a ratio of an amount of the first C 4 off gas stream sent to the C 4 HCl absorber to a total amount of the C 4 off gas stream; C is a C 5-6 feed rate; and D is a fraction of HCl recovered from a combination of the first C 4 off gas stream and the second C 5-6 off gas stream sent to the C 4 HCl absorber.

12. An integrated process for C 4 isomerization and C 5-6 isomerization comprising:
passing a C 5-6 feed stream comprising normal pentane and normal hexane to a C 5-6 HCl absorber forming a C 5-6 absorber bottoms stream comprising normal pentane, normal hexane and HCl and a C 5-6 absorber overhead stream comprising a trace amount of HCl;
passing a first hydrogen rich gas stream and a chloride feed stream containing an organic chloride compound to an organic chloride decomposition reactor containing a chloride decomposition catalyst to decompose the organic chloride compound to form a chloride effluent stream comprising hydrogen, hydrocarbon, and HCl;
passing the C 5-6 absorber bottoms stream and the chloride effluent stream to a C 5-6 isomerization reaction zone under C 5-6 isomerization conditions in the presence of a C 5-6 isomerization catalyst to convert a portion of the normal pentane and normal hexane to iso-pentane and iso-hexane, forming a C 5-6 isomerization effluent comprising normal pentane,

Assignees

• Uop Llc

Inventors

• Kumar Manoj
• Shecterle David J

Classifications

• C07C2527/126

  Aluminium chloride · CPC title

• C07C5/2721 Primary

  Metal halides; Complexes thereof with organic compounds · CPC title

• C07C5/2791 Primary

  with metals · CPC title

• C07C2523/755

  Nickel · CPC title

• C07C2523/44

  Palladium · CPC title