Method and apparatus for liquefying a gas rich in carbon dioxide

Patent metadata

Field	Value
Publication number	US-2024255218-A1
Application number	US-202218290045-A
Country	US
Kind code	A1
Filing date	May 4, 2022
Priority date	May 12, 2021
Publication date	Aug 1, 2024
Grant date	—

Abstract

A method for liquefying a CO2-rich gas flow containing at least 90 mol % of CO2 involves the following steps: compressing the CO2-rich gas flow, liquefying and separating in order to produce a first liquid flow at a first pressure MP and a first temperature T1. Extracting part of the first liquid flow at the first pressure and the first temperature by way of first product, supercooling part of the first liquid flow down to a temperature below the first temperature by indirect exchange of heat in a heat exchanger, expanding the liquid supercooled down to the second temperature T2 until it reaches a second pressure lower than the first pressure, the second pressure being equal to or greater than the equilibrium pressure of the expanded liquid, and extracting part of the expanded liquid by way of second product and evaporating another part of the liquid in the heat exchanger by exchange of heat with the part of the first flow in order to produce a vaporized liquid.

First claim

1 - 14 . (canceled)

15 . A method for liquefying a gas flow rich in CO 2 containing at least 90 mol % of CO 2 comprising the following steps:
a) compression and possibly drying of the gas flow rich in CO 2 in a compressor b) liquefaction and separation by distillation and/or phase separation to produce a first liquid flow at a first pressure MP and a first temperature T 1 c) extraction of a portion of the first liquid flow at the first pressure and the first temperature as a first product d) subcooling of a portion of the first liquid flow to a temperature below the first temperature by indirect heat exchange in a heat exchanger e) expansion of a portion of the subcooled liquid to a second pressure below the first pressure to form a second product f) expansion of the remainder of the subcooled liquid to a third pressure and vaporization of the remainder of the expanded in the heat exchanger by heat exchange with the portion of the first flow to produce a vaporized liquid, and potentially g) recycling of at least a portion of the vaporized liquid flow to step and/or step.

16 . The method as claimed in claim 15 , wherein the first pressure is greater than 14 bar.

17 . The method as claimed in claim 15 , wherein the first temperature is up to 5° C. less than the equilibrium temperature or equal to the equilibrium temperature.

18 . The method as claimed in claim 15 , wherein the second pressure is equal to or less than 10 bar.

19 . The method as claimed in claim 15 , wherein the second temperature is up to 5° C. less than the equilibrium temperature or equal to the equilibrium temperature.

20 . The method as claimed in claim 15 , wherein vaporized gas in the heat exchanger transfers cold to the gas flow rich in CO 2 .

21 . The method as claimed in claim 15 , wherein the heat exchanger exchanges heat between the expanded liquid and the portion of the first liquid flow only.

22 . The method as claimed in claim 15 , wherein the compressor compresses the flow rich in CO 2 to at least 60 bar, the flow at at least 60 bar is cooled in a second heat exchanger to a temperature below 35° C. before being liquefied.

23 . The method as claimed in claim 15 , wherein vaporized gas in the heat exchanger is conveyed to a point upstream of the liquefaction of the gas flow, for example an inter-stage point of the compressor, which performs the compression step.

24 . The method as claimed in claim 15 , wherein the third pressure is less than the second pressure.

25 . The method as claimed in claim 24 , wherein the third pressure is between 5 and 6 bar.

26 . A method for modifying an apparatus for liquefying a gas flow rich in CO 2 containing at least 90 mol % of CO 2 , wherein the apparatus comprises:
a) a compressor and means for conveying the gas flow rich in CO 2 to the compressor b) liquefying means connected to the compressor to liquefy the gas flow rich in CO 2 and means of separation by distillation and/or phase separation to separate the liquefied gas flow to produce a first liquid flow as an end product at a first pressure MP and a first temperature T 1 ;
wherein the method comprises the steps of:
adding the following components to the apparatus:
a heat exchanger,
means for conveying a portion of the first liquid flow to cool in the heat exchanger,
means for expanding a first portion of the first liquid cooled in the heat exchanger and for outputting said expanded liquid as a second end product, and
means for expanding a second portion of the first cooled liquid, separately from the first portion of the first liquid, connected to the heat exchanger to enable a heat exchange between the first liquid and the portion of the first expanded liquid.

27 . The method as claimed in claim 26 , wherein the step of adding the following components to the apparatus includes adding means for conveying at least some of the portion of the heated expanded first liquid in the heat exchanger to the compressor or to another compressor to be compressed.

28 . The method as claimed in claim 26 , wherein a dedicated compressor compresses the heated expanded first liquid.

Assignees

• Lair Liquide Sa Pour Letude Et L’Exploitation Des Procedes Georges Claude

Inventors

• Rodrigues Guillaume
• Madelaine Laurette
• Tran Michael

Classifications

• F25J2290/34

  Details about subcooling of liquids · CPC title

• F25J2220/82

  Separating low boiling, i.e. more volatile components, e.g. He, H2, CO, Air gases, CH4 · CPC title

• F25J1/0274

  Retrofitting or revamping of an existing liquefaction unit · CPC title

• F25J1/0202

  in a quasi-closed internal refrigeration loop (F25J1/0208, F25J1/0219, F25J1/0224 take precedence) · CPC title

• F25J1/0045

  by vaporising a liquid return stream · CPC title