Carbon dioxide capture from flue gas

A system for efficiently separating carbon dioxide from a flue gas of a hydrocarbon processing plant, comprising

• a flue gas conduit configured to receive a flue gas from a hydrocarbon processing plant;
• a compressor in fluid communication with the flue gas conduit, the compressor configured to receive flue gas and compress the flue gas to yield a compressed flue gas;
• a first heat exchanger configured to dissipate heat from the compressed gas using a first coolant to yield a partially cooled gas stream;
• a second heat exchanger having a coolant chamber and a flue gas chamber, the flue gas chamber having an inlet configured to receive the partially cooled gas stream downstream from the first heat exchanger and configured to dissipate heat to the coolant chamber to yield a cold compressed gas stream in the second flue gas chamber, wherein the coolant chamber is configured to receive the cold compressed gas stream downstream from the second flue gas chamber;
• and
• a third heat exchange and/or a first expansion chamber in fluid communication with the second heat exchanger, the third heat exchanger and/or first expansion chamber configured to cool the cold compressed gas stream to yield a condensed carbon dioxide.

A method for efficiently separating carbon dioxide from a flue gas of a hydrocarbon processing plant, comprising:

• (i) removing moisture from a flue gas of a hydrocarbon processing plant to yield an at least partially dried flue gas;
• (ii) compressing the at least partially dried flue gas to yield a compressed-gas stream, wherein the compressed gas stream includes carbon dioxide;
• (iii) reducing the temperature of the compressed-gas stream to a temperature T1 using a first heat exchanger;
• (iv) condensing one or more impurities in the compressed-gas stream using a third heat exchanger and removing the condensed impurities from the compressed-gas stream to yield a purified condensed gas stream that includes carbon dioxide;
• (iv) reducing the temperature of the purified compressed-gas stream to a second temperature T2 using a second heat exchanger or using a second heat exchanger in combination with expansion of the compressed-gas stream, wherein T2<T1 and wherein at least a portion of the carbon dioxide from the purified compressed gas stream condenses, thereby yielding a purified solid or liquid condensed-phase carbon dioxide component and a light-gas component;
• (v) separating the condensed-phase component from the light gas component to produce a condensed-phase stream and a light-gas stream;
• and
• (vi) using at least a portion of the light-gas stream in the second heat exchanger.