Advanced C2-splitter feed rectifier

• US 20080141713A1
• Filed: 12/16/2006
• Published: 06/19/2008
• Est. Priority Date: 12/16/2006
• Status: Active Grant

• Current Assignee: Kellogg Brown & Root LLC (KBR Incorporated)
• Original Assignee: Kellogg Brown & Root LLC (KBR Incorporated)
• Inventors: Verma, Vijender Kumar
• Granted Patent: US 9,103,586 B2
• Time in Patent Office: Days
• US Class Current: 62/630
• CPC Class Codes: C07C 11/02 Alkenes
• CPC Class Codes: C07C 11/24 Acetylene production of acetylene gas by wet methods C10H
• CPC Class Codes: C07C 7/005 Processes comprising at least two steps in series
• CPC Class Codes: F25J 2200/74 Refluxing the column with at least a part of the partially condensed overhead gas
• CPC Class Codes: F25J 2200/78 Refluxing the column with a liquid stream originating from an upstream or downstream fractionator column
• CPC Class Codes: F25J 2215/62 Ethane or ethylene
• CPC Class Codes: F25J 2270/90 External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration
• CPC Class Codes: F25J 2290/80 Retrofitting, revamping or debottlenecking of existing plant
• CPC Class Codes: F25J 3/0219 Refinery gas, cracking gas, coke oven gas, gaseous mixtures containing aliphatic unsaturated CnHm or gaseous mixtures of undefined nature
• CPC Class Codes: F25J 3/0233 separation of CnHm with 1 carbon atom or more
• CPC Class Codes: F25J 3/0238 separation of CnHm with 2 carbon atoms or more
• CPC Class Codes: F25J 3/0242 separation of CnHm with 3 carbon atoms or more

Abstract

Processes to separate a light hydrocarbon stream comprising ethylene, ethane, and C3+ hydrocarbons into an ethylene stream, an ethane stream, and a C3+ hydrocarbon stream, including: feeding the light hydrocarbon stream to a deethanizer; separating the light hydrocarbons in the deethanizer to form a C3+ hydrocarbon bottoms stream and a C2-rich overhead stream comprising ethylene and ethane; separating the C2-rich stream in a C2-rectifier to form a first ethylene stream and an ethane-rich bottoms stream; and separating the ethane-rich bottoms stream in a C2-splitter to form a second ethylene stream and an ethane stream.

Claims

1. ) A process to separate one or more light hydrocarbon streams comprising ethylene, ethane, and C3+ hydrocarbons into an ethylene stream, an ethane stream, and a C3+ hydrocarbon stream, comprising:

feeding the light hydrocarbon streams to a deethanizer;

separating the light hydrocarbons in the deethanizer to form a C3+ hydrocarbon bottoms stream and a C2-rich overhead stream comprising ethylene and ethane;

separating the C2-rich stream in a C2-rectifier to form a first ethylene stream and an ethane-rich bottoms stream; and

separating the ethane-rich bottoms stream in a C2-splitter to form a second ethylene stream and an ethane stream.

2. ) The process of claim 1, wherein the C2-rich overhead stream further comprises acetylene, and the process further comprises

recovering the acetylene in an acetylene recovery unit to form an acetylene stream and a stream lean in acetylene;

feeding the stream lean in acetylene to the C2-rectifier.

3. ) The process of claim 1, wherein the C2-rich overhead stream further comprises acetylene, the process further comprising:

contacting the C2-rich overhead stream with hydrogen rich stream in an acetylene converter unit to convert the acetylene to ethane and ethylene to form a stream lean in acetylene;

feeding the acetylene-lean stream to the C2-rectifier.

4. ) The process of claim 1 wherein the light hydrocarbon stream comprises a product stream from a depropanizer, a demethanizer, a debutanizer, a demethanizer stripper, a cracker furnace effluent, or a combination thereof.

5. ) The process of claim 1 wherein the C2-rectifier is fitted with a reboiler to further increase the first ethylene stream.

6. ) The process of claim 1 wherein the C2-rectifier is fitted with a reboiler to further increase the second ethylene stream.

7. ) A method to retrofit a process to separate light hydrocarbons comprising operation of a deethanizer to separate the light hydrocarbons into a C3+ hydrocarbon bottoms stream and a C2-rich overheads stream comprising ethylene and ethane, and a C2-splitter to separate the C2-rich overheads into an ethylene stream and an ethane stream, wherein the ethylene is condensed and collected in a C2-splitter overheads condensation system, wherein the C2-splitter is capacity-limited, the method comprising:

installing a C2-rectifier to separate the C2-rich overheads into a second ethylene stream and an ethane-rich stream;

installing a line to transmit the C2-rich overheads to the C2-rectifier; and

installing a line to transmit the ethane-rich stream to the C2-splitter;

8. ) The method of claim 7 comprising:

installing a line to transmit the second ethylene stream to the C2-splitter overheads condensation system; and

installing a line to transmit reflux from the overhead condensation system to the C2-rectifier.

9. ) The method of claim 8 comprising installing a C2-rectifier overheads condensation system to condense and collect the ethylene in the second ethylene stream and to supply reflux to the C2-rectifier.

10. ) The method of claim 8 comprising:

installing a line to transmit a C2-rectifier overhead stream to the C2-splitter overheads condensation system; and

installing a line to transmit reflux from the overhead condensation system to the C2-rectifier;

installing a line to collect the second ethylene stream as a side-draw from the C2-rectifier.

11. ) The method of claim 7 wherein the process to separate light hydrocarbons further comprises operating an acetylene recovery unit.

12. ) The method of claim 7 wherein the C2-rectifier is fitted with a reboiler to further increase the first ethylene stream.

13. ) The method of claim 7 wherein the C2-rectifier is fitted with a reboiler to further increase the second ethylene stream.