JP2013010079A - Carbon dioxide separation method and separation apparatus from carbon dioxide-mixed gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon dioxide separation apparatus collecting high-concentration carbon dioxide from a gas containing the carbon dioxide with high collection rate though an apparatus scale is compact.SOLUTION: A mixture gas is sent to a PSA tower 2 from a gas line 1, and the gas from which carbon dioxide is removed is discharged to a gas line 1a and is supplied to a target facility 9 (step 1). Carbon dioxide is desorbed from an inner adsorbent of a PSA tower 2a (step 2). The carbon dioxide separated by sending a gas from the PSA tower 2a to a supersonic nozzle 5 from a gas line 4 is supplied to a tank 8 (step 3). Because the supersonic nozzle 5 is difficult to perfectly separate only carbon dioxide, a gas believed to contain carbon dioxide is sent to the PSA tower 2a from the supersonic nozzle 5, and the carbon dioxide mixed in the gas is adsorbed to obtain the gas from which the carbon dioxide is removed (step 4). In the next cycle, roles of the PSA tower 2, the PSA tower 2a, and a PSA tower 2b are changed, it is returned to the step 1, and the step 1 is executed.

Description

  The present invention relates to a method and apparatus for separating carbon dioxide from a gas containing carbon dioxide generated in a thermal power generation facility or the like.

  For example, a large amount of gas containing carbon dioxide is generated in thermal power generation facilities and steelworks. Carbon dioxide has been conventionally released into the atmosphere along with other exhaust gases. However, due to concerns about global warming due to the greenhouse effect of carbon dioxide in the atmosphere, it does not increase the concentration of carbon dioxide in the atmosphere. Today, the importance of separating carbon dioxide from various industrial process emissions and not releasing them into the atmosphere is recognized.

  A chemical absorption method using an amine compound is a practical treatment method for separating carbon dioxide from a gas containing carbon dioxide such as combustion exhaust gas. A solution of an amine compound is used as the carbon dioxide absorption liquid. Combustion exhaust gas and the absorption liquid are brought into contact with each other in a relatively low temperature and high pressure absorption tower to absorb carbon dioxide into the absorption liquid, and then the absorption liquid is relatively high temperature and low pressure. The carbon dioxide is recovered from the absorption liquid by sending it to the regeneration tower and heating and depressurizing the absorption liquid.

Although it depends on the type of amine compound to be used, when describing an example of monoethanolamine (MEA), the amount of carbon dioxide absorbed per unit absorbent is 16-22 Nm ³ / m ³ and the concentration of carbon dioxide remaining in the supply gas is 5 ˜100 ppm, the energy required for carbon dioxide separation is 4.3 to 6.4 GJ / ton-CO ₂ .

  Thus, the separation of carbon dioxide requires a great amount of energy and cost.

  A carbon dioxide separation method different from the chemical absorption method is the same as the chemical absorption method in that an absorbing solution is used, but there is also a physical absorption method that uses a difference in gas solubility due to pressure rather than a chemical reaction. However, the amount of heat and cost required for carbon dioxide separation still require a great amount of heat and cost as in the chemical absorption method.

  In addition, as a physical adsorption method, a pressure swing adsorption method that uses an adsorbent with different adsorption performance depending on the type of gas, adsorbs a specific gas component under high pressure, and recovers the gas adsorbed under low pressure. There is also (PSA). This method is dry, and does not require waste liquid treatment such as chemical absorption method or physical absorption method using absorption liquid or replenishment of absorption solution accompanying scattering.

  However, since the concentration rate in one stage is limited, in order to separate carbon dioxide with a high concentration and a high recovery rate, it is necessary to repeatedly process it in a multi-stage system, which increases the scale of the apparatus.

  In Patent Document 1, in order to improve the concentration rate of carbon dioxide without providing multiple stages of PSA, the gas in which carbon dioxide is concentrated with PSA is compressed, and the carbon dioxide in the gas is liquefied using a Joule-Thompson valve, A system for recovering carbon dioxide with high purity by recirculating non-condensable gas back to PSA and recovering carbon dioxide in the non-condensable gas is described.

  Patent Document 2 describes a system that separates a mixed gas of hydrogen and carbon dioxide using a PSA, a hydrogen permeable membrane, and a carbon dioxide permeable membrane. After concentrating carbon dioxide with PSA, hydrogen is separated with a hydrogen permeable membrane, and then carbon dioxide is separated with a carbon dioxide permeable membrane.

  Further, in Patent Document 3, a gas containing carbon dioxide is adiabatically expanded by a supersonic nozzle to cool the gas and condense the carbon dioxide, and further add a swirling flow to collect the condensed carbon dioxide outside the nozzle. Are described. Unlike the Joule-Thompson expansion of Patent Document 1, the adiabatic expansion by the supersonic nozzle can cool any gas containing hydrogen, and the temperature can also be lowered from the Joule-Thompson expansion.

JP-A-4-359785 JP 2008-247632 A Special table 2010-500163

  However, in the technique described in Patent Document 1, the temperature change of Joule-Thompson expansion differs depending on the type of gas. For example, when the mixed gas is hydrogen and carbon dioxide, when the mixed gas of 26 atm and −50 degrees C described in Patent Document 1 is Joule-Thompson expanded, hydrogen is Joule-Thompson expanded at that temperature. Since it rises, there is a concern that carbon dioxide cannot be liquefied sufficiently.

  In addition, even if carbon dioxide is liquefied under these conditions, a relatively high concentration of carbon dioxide of about 30% is contained in the non-condensable gas. Therefore, when it is refluxed to PSA, the amount of gas processed by PSA increases. Therefore, it is necessary to increase the scale of the PSA device.

  In the technique described in Patent Document 2, since the separation performance of the permeable membrane is limited, it is necessary to recirculate gas containing carbon dioxide having a relatively high concentration of about 30% to the PSA inlet even after membrane separation. Yes, it is necessary to increase the scale of PSA equipment.

  Furthermore, in the technique described in Patent Document 3, since the temperature rises again when the gas flow velocity returns from supersonic to subsonic, the carbon dioxide condensed in the swirling flow is collected outside and separated in the supersonic state. For this reason, it is difficult to separate the entire amount of carbon dioxide, and about several percent of carbon dioxide that could not be recovered remains in the gas after separating and removing the carbon dioxide.

  Thus, in order to separate carbon dioxide from gas containing carbon dioxide with a high recovery rate and high concentration, it is necessary to recirculate to PSA even if a Joule-Thomson valve, a hydrogen permeable membrane, and a carbon dioxide permeable membrane are provided in PSA. Even if a certain gas flow rate increases and the PSA apparatus is not multistaged, it is necessary to sufficiently increase the scale of the PSA apparatus. In the case of a supersonic nozzle, it is difficult to increase the carbon dioxide recovery rate.

  An object of the present invention is to realize a carbon dioxide separation method and a separation apparatus capable of recovering carbon dioxide from a gas containing carbon dioxide at a high recovery rate and high concentration while having a compact apparatus scale.

  In order to achieve the above object, the present invention is configured as follows.

  A carbon dioxide mixed gas is passed through an adsorption tower having a carbon dioxide adsorbent to remove carbon dioxide, the carbon dioxide adsorbed by the carbon dioxide adsorbent is desorbed, and the gas obtained by the desorption treatment is used as a supersonic nozzle. A carbon dioxide adsorbent, wherein the carbon dioxide separation treatment is performed by supplying the remaining gas that has been subjected to the carbon dioxide separation treatment by the supersonic nozzle to the adsorption tower. While repeating adsorption and desorption of carbon dioxide in an adsorption tower having a carbon dioxide, carbon dioxide is separated by the supersonic nozzle, and carbon dioxide is separated and recovered from the carbon dioxide mixed gas.

  While the apparatus scale is compact, it is possible to realize a carbon dioxide separation method and a separation apparatus that can recover carbon dioxide from a gas containing carbon dioxide at a high recovery rate and high concentration.

It is a schematic block diagram of the carbon dioxide separator which is one Example by this invention. It is a graph which shows the calculation result of the time change of the carbon dioxide concentration of the gas which flows in in and flows out of the PSA tower in one example of the present invention. It is a graph which shows the calculation result of the time change of the carbon dioxide adsorption amount in the PSA tower in one Example of this invention. It is a graph which shows the Mach number of gas, the fall rate of a pressure and temperature, and the ratio of a nozzle cross-sectional area. It is a figure which shows the modification of one Example by this invention. It is an operation | movement flowchart in one Example of this invention. It is internal structure explanatory drawing of a supersonic nozzle.

  Hereinafter, embodiments of a carbon dioxide separation method and a separation apparatus according to the present invention will be described with reference to the accompanying drawings.

  The present invention works with the PSA tower and the supersonic nozzle, and separates the carbon dioxide with the supersonic nozzle while repeating the adsorption and desorption of carbon dioxide in the PSA tower, thereby minimizing the scale of the apparatus. It is the method and apparatus which can isolate | separate a carbon dioxide from the mixed gas containing this by the high recovery rate and high concentration.

  FIG. 1 is a schematic system configuration diagram of a carbon dioxide separator according to an embodiment of the present invention.

  In FIG. 1, a gas pipe 1 for sending a gas containing carbon dioxide from a thermal power plant or the like is connected to a gas supply inlet at one end of a pressure swing adsorption (PSA) tower 2, 2a, 2b. The gas pipe 1a is connected to a gas supply / discharge port at the other end of the pressure swing adsorption (PSA) tower 2, 2a, 2b. The gas pipe 1 a is connected to the target facility 9. This target facility 9 is, for example, a hydrogen storage. The pressure swing adsorption (PSA) towers 2, 2a, 2b are equipped with carbon dioxide adsorbents 20, 21, 22 respectively.

  Gas is supplied to and discharged from each pressure swing adsorption (PSA) tower 2, 2a, 2b via valves 3a-3o.

  In addition, one end of each pressure swing adsorption (PSA) tower 2, 2 a, 2 b is connected to a supersonic nozzle 5 having guide blades 11 via valves 3 g, 3 h, 3 i and piping 4. The supersonic nozzle 5 is connected to the pipe 1 through valves 3b, 3d, and 3f. Furthermore, the supersonic nozzle 5 is connected to a tank 8 for storing carbon dioxide.

  The valves 3a to 3o are controlled to open and close by a command signal from the controller (sequencer) 10.

  FIG. 6 is an operation flowchart of the first embodiment shown in FIG. This operation is executed when the controller 10 performs a valve opening / closing operation control by sending a command signal to each of the valves 3a to 3o and the supersonic nozzle 5. In addition, this cycle is repeated by repeating steps 1 to 4 described later as one cycle, and the carbon dioxide is separated while changing the roles of a plurality of PSA towers, thereby effectively utilizing the equipment and preventing the equipment scale from being expanded. ing.

  1 and 6, first, in step 1, a mixed gas containing carbon dioxide such as combustion exhaust gas from a thermal power plant is desulfurized and dehydrated (not shown), and then passed through a gas pipe 1. It is sent to a pressure swing adsorption (PSA) tower 2.

  The PSA tower 2 is filled with an adsorbent (part indicated by oblique lines) 20 that adsorbs carbon dioxide, and the gas from which the carbon dioxide has been removed from the mixed gas until the carbon dioxide adsorption is saturated is the PSA tower. 2 is discharged to the gas pipe 1a. This determines whether the adsorption of carbon dioxide is saturated by determining whether a predetermined time has elapsed. The gas excluding carbon dioxide is supplied to the target facility 9 and stored.

  Next, when the adsorbent is saturated with carbon dioxide, the process proceeds to step 2, and the inside of the PSA tower 2a where the adsorption of carbon dioxide is saturated in the previous cycle is depressurized to desorb the carbon dioxide adsorbed on the adsorbent 21. Let At this time, a part of the gas from which the carbon dioxide obtained in the process of step 1 is removed from the valve 3l is purged, and the gas containing the desorbed carbon dioxide is discharged to the pipe 4. In order to perform a purge using a part of this gas, a pressure reducer (not shown) may be connected in the vicinity of the valve 3l, or the opening degree of the valve 3l may be adjusted. The same applies to the valves 3i and 3n of the other PSA towers 2 and 2b.

  Next, the process proceeds to step 3, and the gas containing carbon dioxide desorbed from the PSA tower 2 a is sent from the pipe 4 to the supersonic nozzle 5. In the supersonic nozzle 5, the flow velocity of the gas containing carbon dioxide is accelerated to supersonic velocity, the temperature is lowered as the flow velocity is increased, and carbon dioxide having a high condensation temperature is condensed among the gas components.

  The supersonic nozzle 5 is provided with guide vanes 11 for causing a swirling flow. The carbon dioxide condensed by the swirling is collected near the outer surface in the supersonic nozzle 5, and the flow path is obtained when it is sufficiently collected. Is divided into an outer side and an inner side to separate carbon dioxide. The separated carbon dioxide is supplied to the tank 8.

  Here, the internal configuration and function of the supersonic nozzle 5 will be described with reference to FIG. In FIG. 7, a core 24 is provided at the center of the supersonic nozzle 5, and the gas flows through a cylindrical flow path around the core 4. A swirl vane 11 is provided on the upstream side of the supersonic nozzle 5, and the gas flows while swirling in the cylindrical flow path by passing through the swirl vane 11. The flow path cross-sectional area is gradually reduced, and the velocity of the axial direction increases while the gas swirls.

  In the vicinity of the throat 23 where the cross-sectional area of the flow path is minimum, the gas becomes sonic, and as the flow path expands again, the gas further increases in flow velocity and becomes supersonic. At supersonic speed, the temperature of the gas decreases rapidly, and when the temperature falls below the condensation temperature of carbon dioxide, the carbon dioxide in the gas condenses into particles. The condensed carbon dioxide is collected outside the separation tube 25 by centrifugal force due to the swirling flow of gas. By separating the carbon dioxide sufficiently outside the separation tube 25 into the center and the periphery of the separation tube 25, a gas having a reduced carbon dioxide concentration can be obtained from the center of the separation tube 25. A gas containing a large amount of carbon dioxide can be obtained from the surroundings.

  In the supersonic nozzle 5, it is difficult to completely separate only carbon dioxide, and a part of the carbon dioxide is mixed in the gas inside the supersonic nozzle 5. Therefore, in the step 4, the gas that will contain carbon dioxide from the supersonic nozzle 5 is sent to the PSA tower 2a after desorbing carbon dioxide in the previous cycle, and the carbon dioxide mixed in the gas is sent. Adsorbed to obtain gas without carbon dioxide.

  The operation of step 4 is executed until a predetermined time elapses, and after the predetermined time elapses, the process proceeds to the next cycle.

  The operation of the next second cycle is executed by returning to Step 1, but in the second cycle, the PSA tower targeted for Step 1 is the PSA tower 2b, and the PSA tower targeted for Steps 2 and 3 is The PSA tower 2 which is the PSA tower 2 and is the target of Step 4 is the PSA tower 2a.

  In the third cycle, the PSA tower targeted for Step 1 is the PSA tower 2a, the PSA tower targeted for Steps 2 and 3 is the PSA tower 2b, and the PSA tower targeted for Step 4 is the PSA tower. Tower 2.

  When the third cycle ends, the operation returns to the first cycle.

  Next, calculation results when the first embodiment of the present invention is applied to a gas containing 33.5% carbon dioxide will be described below. However, the carbon dioxide adsorbent packed in the PSA tower was assumed to be molecular sieve charcoal, and the saturated adsorption amount, Langmuir constant, and mass transfer coefficient were set and calculated.

  FIG. 2 is a graph showing changes over time in the carbon dioxide concentration of the gas flowing into and out of the PSA tower and the gas in the center of the PSA tower. The dark line in FIG. 2 indicates the outflow gas, and the thin line indicates the inflow gas. And a dotted line shows the carbon dioxide concentration in a PSA tower center part. The vertical axis in FIG. 2 indicates the carbon dioxide mole fraction of the gas, and the horizontal axis indicates time (min). FIG. 3 shows the change over time in the amount of carbon dioxide adsorbed on the upper and center adsorbents of the PSA tower, the solid line shows the change at the tower upper side, and the dotted line shows the change at the center of the tower. And the vertical axis | shaft of FIG. 3 shows the adsorption amount of a carbon dioxide, and a horizontal axis shows time (min).

  First, in step 1 above, a gas containing 33.5% carbon dioxide is introduced into the PSA tower 2 at a pressure of 2 MPa for 6 minutes. 6 minutes was set as the time when carbon dioxide does not break through. As shown in FIG. 2, the carbon dioxide concentration in the effluent gas is almost zero. Further, as shown in FIG. 3, the amount of carbon dioxide adsorbed near the upper side of the PSA tower 2 is approaching saturation, but the amount of adsorption is still about half of the upper side at the center of the PSA tower 2.

  Next, in step 2, the pressure inside the PSA tower 2a is reduced to 0.1 MPa, and part of the gas excluding carbon dioxide in step 1 is introduced into the PSA tower 2a from the opposite valve 3l for 10 minutes. .

  Then, the carbon dioxide adsorbed on the adsorbent is desorbed and flows out from the PSA tower 2a. As shown in FIG. 2, the change in the carbon dioxide concentration at this time increases gradually to a maximum of nearly 70% and then gradually decreases. Further, as shown in FIG. 3, immediately before the end of step 2, the amount of carbon dioxide adsorbed becomes almost zero, and the carbon dioxide is completely desorbed.

  Next, in step 3, the gas flowing out from the PSA tower 2 a in step 2 is sent to the supersonic nozzle 5. In order to accelerate the gas with the supersonic nozzle 5, it is necessary to provide a pressure difference between the inlet and the outlet of the supersonic nozzle 5. Further, since the carbon dioxide concentration of the gas flowing out from the PSA tower 2a also varies greatly with time, a buffer tank 6 and a compressor are disposed in the middle of the pipe 4 from the PSA tower 2a to the supersonic nozzle 5, as shown in FIG. 7 to average the carbon dioxide concentration and increase the pressure to 2 MPa. The average value of the carbon dioxide concentration of the gas flowing out of the PSA tower 2a in step 2 is 27.8%.

  The supersonic nozzle 5 has a structure in which the channel cross-sectional area is initially reduced, and the channel cross-sectional area is increased again via a minimum part of the channel cross-sectional area called a throat. The gas flowing through the supersonic nozzle 5 initially increases in flow velocity with a decrease in the cross-sectional area of the flow path in the subsonic state, and reaches a flow velocity just equal to the sound velocity at the throat portion. Furthermore, this time, the flow velocity increases with an increase in the cross-sectional area of the channel, and a supersonic state is obtained.

  The ratio of the gas flow velocity to the sound velocity is called the Mach number M, where M <1 is subsonic and M> 1 is supersonic. The pressure and temperature of the gas decrease as the gas flow rate, that is, the Mach number M increases.

  FIG. 4 is a diagram showing the relationship between the Mach number, temperature, pressure, and flow path cross-sectional area when it is assumed that the gas viscosity is negligible and the gas component is not condensed. As shown in FIG. 4, when the gas exceeds the speed of sound and becomes supersonic, the temperature and pressure are greatly reduced.

  Assuming an isentropic flow in the supersonic nozzle 5, if a gas having a pressure of 2 MPa and a temperature of 300 K is accelerated by the supersonic nozzle 5 to a Mach number of 2.6, the pressure is 0.1 MPa and the temperature is about 130 K. descend. Since the condensation temperature of carbon dioxide is 194 K at 0.1 MPa, the carbon dioxide in the gas is condensed.

  The supersonic nozzle 5 is also provided with a mechanism for generating a swirling flow by the guide blades 11, and the condensed carbon dioxide gathers around the supersonic nozzle 5 by centrifugal force, and the concentration of carbon dioxide decreases near the center. To do.

  Therefore, when the gas flow path is divided into the center and the periphery on the downstream side of the supersonic nozzle 5, it is separated into the surrounding condensed carbon dioxide and gas having a low carbon dioxide concentration. Since the carbon dioxide separation efficiency of the supersonic nozzle 5 largely depends on the structure of the nozzle, it is assumed in this calculation that 80% of the carbon dioxide can be separated and 20% remains in the gas.

  If it does so, the carbon dioxide concentration of gas after separating carbon dioxide with supersonic nozzle 5 will be 5.6%. This gas is caused to flow into the PSA tower 2a after desorbing carbon dioxide in the next step 4 step.

  As shown in FIG. 5, the gas after the carbon dioxide is separated by the supersonic nozzle 5 can also flow into the PSA tower 2a through the buffer tank 6a and the compressor 7a at a pressure of 2 MPa. In the PSA tower 2a, carbon dioxide in the gas is adsorbed, and the gas having a carbon dioxide concentration of approximately 0 flows out.

  Since the concentration of carbon dioxide is as low as 5.6%, as shown in FIG. 3, the amount of carbon dioxide adsorbed is only about half of the amount adsorbed in step 1 even after all the gases have been processed. It is still possible to adsorb carbon dioxide. Therefore, it is possible to continue to the step 1 process without desorbing carbon dioxide after the step 4 process.

  As described above, in one embodiment of the present invention, the carbon dioxide is separated from the mixed gas by the first PSA tower, and a portion of the gas from which the gas dioxide is removed is used to absorb the dioxide dioxide adsorbed on the second PSA tower. Carbon is discharged and carbon dioxide is removed by supersonic nozzle. Since the supersonic nozzle cannot completely remove carbon dioxide, the remaining gas is supplied from the supersonic nozzle to the third PSA tower to adsorb carbon dioxide. Then, a gas containing carbon dioxide is newly supplied to the third PSA tower to be adsorbed, and carbon dioxide is adsorbed and desorbed by the same operation.

  Therefore, according to the present invention, as in the techniques described in Patent Document 1 and Patent Document 2, since carbon dioxide is separated without refluxing the treated gas, the gas throughput in the PSA tower increases. There is no problem, and the scale of the PSA tower can be reduced.

  In addition, since the carbon dioxide concentration can be reduced to almost zero in the gas after removing carbon dioxide, the reforming reaction and shift from fossil fuels such as oil and natural gas can be performed in addition to the purpose of separating carbon dioxide. The present invention can also be applied to a method of producing hydrogen by using a reaction to produce a mixed gas of carbon dioxide and hydrogen, and then separating the carbon dioxide.

  Furthermore, the present invention can reduce energy and cost for separating carbon dioxide as compared with a chemical absorption method or a physical absorption method using an absorbing solution.

  In addition, although the example mentioned above is an example using three PSA towers, the present invention is applicable even if one PSA tower is used. That is, a mixed gas from a thermal power plant or the like is supplied to one PSA tower to adsorb carbon dioxide, and then the pressure is reduced, and a gas containing carbon dioxide is supplied to the supersonic nozzle 5 to separate the carbon dioxide. And supply to the external tank. Then, the separated gas is supplied from the supersonic nozzle 5 to the one PSA tower to adsorb carbon dioxide. Then, in the next cycle, the mixed gas from the thermal power plant or the like is supplied to the same one PSA tower in the same manner as described above. Such a configuration can also be adopted.

  DESCRIPTION OF SYMBOLS 1 ... Gas piping, 2, 2a, 2a ... Pressure swing adsorption (PSA) tower, 3a-3o ... Switching valve 4 ... Gas piping, 5 ... Supersonic nozzle, 6, 6a. ..Buffer tank, 7, 7a ... Compressor, 8 ... Tank, 9 ... Target equipment, 10 ... Controller (sequencer), 11 ... Guide blades 20-22 ... Carbon dioxide Adsorbent 23 ... Throat, 24 ... Core, 25 ... Separation tube

Claims (11)

A first step of removing carbon dioxide from the mixed gas by flowing the carbon dioxide mixed gas through an adsorption tower having a carbon dioxide adsorbent and adsorbing the carbon dioxide mixed gas on the carbon dioxide adsorbent;
A second step of desorbing carbon dioxide adsorbed on the carbon dioxide adsorbent by depressurizing the adsorption tower;
A third step of supplying a gas obtained by carbon dioxide desorption treatment of the carbon dioxide adsorbent of the adsorption tower to a supersonic nozzle, performing adiabatic expansion cooling, and performing a carbon dioxide separation treatment;
A fourth step of supplying the remaining gas subjected to carbon dioxide separation treatment by the supersonic nozzle to an adsorption tower having a carbon dioxide adsorbent, and performing carbon dioxide adsorption treatment;
The carbon dioxide is separated and recovered from the carbon dioxide mixed gas by separating carbon dioxide with the supersonic nozzle while repeating adsorption and desorption of carbon dioxide in an adsorption tower having a carbon dioxide adsorbent. Carbon separation method. The carbon dioxide separation method according to claim 1,
The supersonic nozzle in the third step collects and separates carbon dioxide condensed by rotating a gas flow with the supersonic nozzle on the outer periphery of the nozzle. The carbon dioxide separation method according to claim 2,
The supersonic nozzle has guide vanes for swirling the gas flow, and the condensed carbon dioxide collected around the nozzle by the swirling flow is discharged. The carbon dioxide separation method according to claim 2,
The gas obtained by the carbon dioxide desorption process in the third step is temporarily stored in a buffer tank, and the gas sent from the buffer tank is compressed by a compressor and supplied to the supersonic nozzle. To separate carbon dioxide. The carbon dioxide separation method according to claim 1,
The adsorption tower has a first adsorption tower, a second adsorption tower, and a third adsorption tower,
In the first step, carbon dioxide is adsorbed on the carbon dioxide adsorbent of the first adsorption tower, and in the second step, the second adsorption tower is depressurized to desorb, and the fourth step. In the step, the remaining gas that has been subjected to the carbon dioxide separation treatment by the supersonic nozzle is supplied to the third adsorption tower, and the first cycle for the carbon dioxide adsorption treatment is performed.
Subsequently, in the first step, carbon dioxide is adsorbed on the carbon dioxide adsorbent of the third adsorption tower, and in the second step, the first adsorption tower is depressurized to desorb, In the fourth step, the remaining gas subjected to the carbon dioxide separation treatment by the supersonic nozzle is supplied to the second adsorption tower, and a second cycle of carbon dioxide adsorption treatment is performed.
Subsequently, in the first step, carbon dioxide is adsorbed on the carbon dioxide adsorbent of the second adsorption tower, and in the second step, the third adsorption tower is depressurized to desorb, In the fourth step, the remaining gas that has been subjected to the carbon dioxide separation treatment by the supersonic nozzle is supplied to the first adsorption tower, and a third cycle of carbon dioxide adsorption treatment is performed.
Thereafter, the method returns to the first cycle, and the second and third cycles are executed. An adsorption tower having a carbon dioxide adsorbent;
A supersonic nozzle that performs a process of separating carbon dioxide from a gas containing carbon dioxide;
Piping connecting the adsorption tower and the supersonic nozzle;
A plurality of valves connected to the piping to supply and discharge gas to and from the adsorption tower and the supersonic nozzle;
A controller for controlling the operations of the plurality of valves and the supersonic nozzle;
The controller controls the opening and closing operations of the plurality of valves, separates carbon dioxide with the supersonic nozzle while repeating adsorption and desorption of carbon dioxide in an adsorption tower having a carbon dioxide adsorbent, and a carbon dioxide mixed gas A carbon dioxide separator characterized by separating and recovering carbon dioxide from water. The carbon dioxide separator according to claim 6,
The supersonic nozzle collects carbon dioxide condensed by rotating a gas flow by the supersonic nozzle and separates it on the outer periphery of the nozzle. The carbon dioxide separator according to claim 7,
The supersonic nozzle has a guide vane for swirling a soot stream, and discharges condensed carbon dioxide collected around the nozzle by the swirl stream. The carbon dioxide separator according to claim 7,
A buffer tank that temporarily stores a gas obtained by the carbon dioxide desorption process in the third step, and a compressor that compresses the gas sent from the buffer tank and supplies the compressed gas to the supersonic nozzle. A carbon dioxide separator characterized by the above. The carbon dioxide separator according to claim 6,
The controller circulates the carbon dioxide mixed gas through the adsorption tower and adsorbs it to the carbon dioxide adsorbent, and removes carbon dioxide from the mixed gas; and the carbon dioxide adsorbed on the carbon dioxide adsorbent A second step of desorption treatment by depressurizing the adsorption tower, a gas obtained by carbon dioxide desorption treatment of the carbon dioxide adsorbent of the adsorption tower is supplied to a supersonic nozzle, adiabatic expansion cooling is performed, and carbon dioxide And a third step of performing the separation process. The carbon dioxide separator according to claim 10, wherein
The adsorption tower has a first adsorption tower, a second adsorption tower, and a third adsorption tower,
The controller
In the first step, carbon dioxide is adsorbed on the carbon dioxide adsorbent of the first adsorption tower, and in the second step, the second adsorption tower is depressurized to desorb, and the fourth step. In the step, the remaining gas that has been subjected to the carbon dioxide separation treatment by the supersonic nozzle is supplied to the third adsorption tower, and the first cycle for the carbon dioxide adsorption treatment is performed.
Subsequently, in the first step, carbon dioxide is adsorbed on the carbon dioxide adsorbent of the third adsorption tower, and in the second step, the first adsorption tower is depressurized to desorb, In the fourth step, the remaining gas subjected to the carbon dioxide separation treatment by the supersonic nozzle is supplied to the second adsorption tower, and a second cycle of carbon dioxide adsorption treatment is performed.
Subsequently, in the first step, carbon dioxide is adsorbed on the carbon dioxide adsorbent of the second adsorption tower, and in the second step, the third adsorption tower is depressurized to desorb, In the fourth step, the remaining gas that has been subjected to the carbon dioxide separation treatment by the supersonic nozzle is supplied to the first adsorption tower, and a third cycle of carbon dioxide adsorption treatment is performed.
Then, it returns to the said 1st cycle and performs a 2nd, 3rd cycle, The carbon dioxide separator characterized by the above-mentioned.

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