Carbon Dioxide Recovery
The present techniques are directed to a system and method for recovering carbon dioxide (CO 2 ). The method includes recovering the CO 2 from a gas mixture including the CO 2 via a CO 2 separation system. The CO 2 separation system includes a rotating freezer/melter.
1 . A system for recovering carbon dioxide (CO 2 ), comprising a CO 2 separation system configured to recover the CO 2 from a gas mixture, wherein the CO 2 separation system comprises a rotating freezer/melter.
2 . The system of claim 1 , wherein the rotating freezer/melter comprises a freezing zone, a melting zone, and a rotor.
3 . The system of claim 2 , wherein solid CO 2 formed from the CO 2 within the gas mixture is captured on the rotor within the freezing zone, and wherein the gas mixture passes through the rotor within the freezing zone.
4 . The system of claim 3 , wherein the solid CO 2 is formed from the CO 2 within the gas mixture via a heat exchanger and an expander upstream of the rotating freezer/melter.
5 . The system of claim 3 , wherein the solid CO 2 melts and passes through the rotor as liquid CO 2 within the melting zone.
6 . The system of claim 5 , wherein a portion of the liquid CO 2 is recycled to the melting zone of the rotating freezer/melter and used to melt the solid CO 2 within the melting zone.
7 . The system of claim 3 , wherein the CO 2 separation system comprises a CO 2 separation device downstream of the freezing zone of the rotating freezer/melter, and wherein the CO 2 separation device recovers residual CO 2 from the gas mixture.
8 . The system of claim 7 , wherein the CO 2 separation device recovers the residual CO 2 from the gas mixture via an amine separation process.
9 . The system of claim 7 , wherein the CO 2 separation device recovers the residual CO 2 from the gas mixture via a potassium carbonate separation process.
10 . The system of claim 7 , wherein the residual CO 2 recovered via the CO 2 separation device is pressurized via a compressor to produce a pressurized CO 2 vapor stream, and wherein the pressurized CO 2 vapor stream is used to melt the solid CO 2 within the melting zone of the rotating freezer/melter.
11 . The system of claim 1 , comprising a power plant configured to generate power, wherein an exhaust gas from the power plant provides the gas mixture, and wherein the gas mixture comprises the CO 2 , H 2 O, and inert gas.
12 . The system of claim 11 , comprising a dehydration system configured to remove the H 2 O from the gas mixture.
13 . The system of claim 11 , wherein the power plant comprises:
an expander turbine configured to provide mechanical energy by extracting energy from the gas mixture after combustion of the gas mixture in a combustor; and
a generator configured to generate electricity from the mechanical energy provided by the expander turbine.
14 . The system of claim 11 , wherein the power plant comprises a combined cycle power plant.
15 . The system of claim 14 , wherein the combined cycle power plant comprises:
an expander turbine configured to provide mechanical energy by extracting energy from the gas mixture after combustion of the gas mixture in a combustor;
a heat recovery steam generator (HRSG) configured to generate steam by heating a boiler with an exhaust stream from the expander turbine;
a steam turbine configured to provide mechanical energy by extracting energy from the steam generated by the HRSG; and
a generator configured to generate electricity from the mechanical energy provided by the expander turbine and the steam turbine.
16 . The system of claim 11 , wherein a portion of the gas mixture is recycled to the power plant.
17 . The system of claim 1 , wherein the gas mixture comprises a natural gas stream comprising the CO 2 .
18 . A method for recovering carbon dioxide (CO 2 ), comprising recovering the CO 2 from a gas mixture comprising the CO 2 via a CO 2 separation system, wherein the CO 2 separation system comprises a rotating freezer/melter.
19 . The method of claim 18 , wherein recovering the CO 2 from the gas mixture via a CO 2 separation system comprises:
capturing solid CO 2 formed from the gas mixture on a rotor of the rotating freezer/melter while the rotor is in a freezing zone of the rotating freezer/melter;
flowing the gas mixture through the rotor while the rotor is in the freezing zone; melting the solid CO 2 that is captured on the rotor to form liquid CO 2 while the rotor is in a melting zone of the rotating freezer/melter; and
flowing the liquid CO 2 through the rotor while the rotor is in the melting zone.
20 . The method of claim 19 , comprising forming the solid CO 2 from the CO 2 within the gas mixture using a heat exchanger and an expander upstream of the rotating freezer/melter.
21 . The method of claim 19 , comprising:
recycling a portion of the liquid CO 2 to the melting zone of the rotating freezer/melter; and
using the portion of the liquid CO 2 to melt the solid CO 2 within the melting zone.
22 . The method of claim 19 , comprising:
recovering residual CO 2 from the gas mixture via a CO 2 separation device downstream of the freezing zone of the rotating freezer/melter;
pressurizing the recovered residual CO 2 via a compressor to produce a pressurized CO 2 vapor stream; and
using the pressurized CO 2 vapor stream to melt the solid CO 2 within the melting zone of the rotating freezer/melter.
23 . The method of claim 18 , comprising producing power via a power plant, wherein an exhaust gas from the power plant provides the gas mixture, and wherein the gas mixture comprises the CO 2 , H 2 O, and inert gas.
24 . The method of claim 23 , comprising removing the H 2 O from the gas mixture via a dehydration system.
25 . The method of claim 23 , wherein producing the power via the power plant comprises:
providing mechanical energy via an expander turbine using energy extracted from the gas mixture after combustion of the gas mixture in a combustor; and
generating electricity via a generator using the mechanical energy provided by the expander turbine.
26 . The method of claim 23 , wherein producing the power via the power plant comprises:
providing mechanical energy via an expander turbine using energy extracted from the gas mixture after combustion of the gas mixture in a combustor;
generating steam via a heat recovery steam generator (HRSG) by heating a boiler with an exhaust stream from the expander turbine;
providing mechanical energy via a steam turbine using energy extracted from the steam generated by the HRSG; and
generating electricity via a generator using the mechanical energy provided by the expander turbine and the steam turbine.
27 . A rotating freezer/melter for recovering carbon dioxide (CO 2 ) from a gas mixture, comprising:
a freezing zone;
a melting zone; and
a rotor configured to rotate through the freezing zone and the melting zone;
wherein solid CO 2 formed from a gas mixture is captured on the rotor while the rotor is rotating through the freezing zone, and wherein the solid CO 2 melts and flows through the rotor as liquid CO 2 while the rotor is rotating through the melting zone.
28 . The rotating freezer/melter of claim 27 , wherein the rotor comprises porous ceramic.
29 . The rotating freezer/melter of claim 27 , wherein the rotor comprises a plurality of layers of metal mesh screens.
30 . The rotating freezer/melter of claim 27 , comprising a sealing device for individually sealing both the freezing zone and the melting zone of the rotating freezer/melter.
31 . The rotating freezer/melter of claim 27 , wherein gaseous components within the gas mixture flow through the rotor while the rotor is rotating through the freezing zone.