Method and apparatus for liquefying and/or separating a mixture containing co2

A process for liquefying and/or separating by distillation and/or partial condensation a carbon dioxide mixture, the process comprising the steps of:

• i) performing at least one of the following steps:
• a. cooling the carbon dioxide the mixture (15, 16) upstream of the separation and/or liquefaction;
• and/or
• b. cooling a cycle gas (23) from a refrigeration cycle that cools the carbon dioxide mixture upstream of the separation and/or liquefaction by a refrigerant stream (26);
• and
• ii) liquefying and/or separating the carbon dioxide mixture,
• wherein the refrigerant stream is produced by an absorption or adsorption refrigeration unit (50) whose heat source is a fluid (21, 21A, 21B) heated by the heat of a conversion of CO to CO2 of a syngas (1, 3, 5), the conversion producing a CO2-enriched syngas (5, 9) from which the carbon dioxide mixture (16) to be cooled is derived.

An apparatus for liquefying and/or separating by distillation and/or partial condensation a carbon dioxide mixture, the apparatus comprising:

• i) means for cooling the carbon dioxide mixture (15, 16) upstream of the separation and/or liquefaction;
• and/or
• ii) a refrigeration cycle (23, 29) comprising means (30) for indirectly contacting a gas of the refrigeration cycle and the carbon dioxide mixture to cool the carbon dioxide mixture upstream of the separation and/or liquefaction;
• iii) means for liquefying the carbon dioxide mixture and/or for separating the carbon dioxide mixture by distillation and/or partial condensation;
• and
• iv) an absorption or adsorption refrigeration unit (50) connected to send a refrigerant stream to the means for cooling the carbon dioxide mixture (15, 16) and/or to a heat exchanger (20) for cooling the cycle gas, the unit being connected to a heat source which is a fluid (21, 21A, 21B) heated by the heat of a CO to CO2 conversion of a syngas (3, 5) in a reactor (4, 8), means for sending CO2-enriched syngas from the reactor as a mixture (16) to be cooled or for sending CO2-enriched syngas from the reactor to an absorption or adsorption unit (17) to form the carbon dioxide mixture (15) to be cooled.

A method for reducing the energy consumption of a carbon dioxide separation or liquefaction process, the method comprising the steps of:

• a) performing a water-gas shift reaction on a syngas stream to convert carbon monoxide into carbon dioxide, thereby generating a CO2-enriched syngas and releasing process heat;
• b) transferring at least a portion of the process heat via a heat transfer fluid to a heat-activated refrigeration unit;
• c) operating the heat-activated refrigeration unit using said process heat to produce a primary refrigerant stream;
• d) providing a process gas stream rich in carbon dioxide, wherein said process gas stream is derived from the CO2-enriched syngas;
• e) using the primary refrigerant stream to cool a target fluid, wherein the target fluid is at least one of:
• i. the process gas stream;
• or ii. a cycle gas of a secondary refrigeration cycle used to cool the process gas stream;
• and
• f) subsequently separating or liquefying carbon dioxide from the cooled process gas stream.