초록 ▼

This invention relates to a device for separating carbon dioxide that includes a self-recycling loop, and to a method of separating carbon dioxide, which serve to effectively separate carbon dioxide from a combustion gas using a separation membrane provided with the self-recycling loop. This inventi

This invention relates to a device for separating carbon dioxide that includes a self-recycling loop, and to a method of separating carbon dioxide, which serve to effectively separate carbon dioxide from a combustion gas using a separation membrane provided with the self-recycling loop. This invention adopts a self-recycling loop in which the residue gas passing through a specific separation membrane is introduced into another separation membrane and in which a permeate gas passing through the specific separation membrane is introduced back into the specific separation membrane. Accordingly, the concentration of carbon dioxide in the feed gas of the specific separation membrane is increased, which increases the concentration of the permeate gas to thus improve the separation performance of the separation membrane, thereby separating high-purity carbon dioxide.

대표청구항 ▼

1. A device for separating carbon dioxide, the device comprising: a first separation membrane into which a combustion gas is fed;a second separation membrane into which a permeate gas of the first separation membrane is fed; anda third separation membrane into which a residue gas of the first separa

1. A device for separating carbon dioxide, the device comprising: a first separation membrane into which a combustion gas is fed;a second separation membrane into which a permeate gas of the first separation membrane is fed; anda third separation membrane into which a residue gas of the first separation membrane is fed,wherein the second separation membrane is provided with a self-recycling loop in which a portion of a permeate gas of the second separation membrane does not pass through a separation membrane other than the second separation membrane but is fed back into the second separation membrane, andwherein the third separation membrane is provided with a self-recycling loop in which a portion of a permeate gas of the third separation membrane does not pass through a separation membrane other than the third separation membrane, but the portion of the permeate gas of the third separation membrane is fed back into the third separation membrane. 2. The device of claim 1, wherein the first separation membrane is provided with a feed side through which the combustion gas is fed and the second separation membrane is provided with a feed side through which the permeate gas of the first separation membrane is fed. 3. The device of claim 2, further comprising a pressurizing means on the feed side. 4. The device of claim 1, further comprising a decompressing means on a permeate side of at least one of the first and second separation membranes. 5. The device of claim 1, wherein the first separation membrane has a pressure of 1.0˜3.0(bar, a) in a feed side and a pressure of 0.1˜0.5(bar, a) in a permeate side, the second separation membrane has a pressure of 1.0˜3.0(bar, a) in a feed side and a pressure of 0.03˜0.5(bar, a) in a permeate side, and the first and second separation membranes have an area ratio of the first separation membrane to the second separation membrane ranging from 1:1 to 3:1. 6. The device of claim 1, wherein the remaining portion of the permeate gas of the third separation membrane is fed back into the first separation membrane. 7. A method of separating carbon dioxide, the method comprising steps of: (a) feeding a combustion gas into a first separation membrane to obtain a first permeate gas and a first residue gas, discharging the first residue gas from the first separation membrane, and feeding the first permeate gas into a second separation membrane;(b) feeding a second residue gas from the second separation membrane into the first separation membrane, and feeding a portion of a second permeate gas from the second separation membrane directly back into the second separation membrane while the portion of the second permeate gas does not pass through a separation membrane other than the second separation membrane to increase a concentration of carbon dioxide in a feed side of the second separation membrane, thereby recycling the second permeate gas that is discharged by passing through a permeate side of the second separation membrane; and(c) feeding the first residue gas from the first separation membrane into a third separation membrane to obtain a third permeate gas and a third residue gas, discharging the third residue gas from the third separation membrane, and feeding a portion of the third permeate gas back into the third separation membrane while the portion of the third permeate gas does not pass through a separation membrane other than the third separation membrane. 8. The method of claim 7, wherein the remaining portion of the third permeate gas of the third separation membrane is fed back into the first separation membrane.