JP2007008732A - System and method for recovering carbon dioxide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system and method for recovering carbon dioxide by which the pressure in a regeneration unit can efficiently be reduced, and the carbon dioxide discharged from the regeneration unit can immediately be dissolved and fixed in sea water or water, and which can promote an energy saving as system. <P>SOLUTION: The system for recovering carbon dioxide is equipped with: an absorption column 170 for absorbing carbon dioxide in an exhaust gas 105 into an absorption liquid 106; a regeneration column 180 for regenerating the absorption liquid 106 by releasing carbon dioxide from the absorption liquid 106 wherein carbon dioxide is absorbed; and a gas dissolving unit 145 which is interposed in a cooling water discharge line 134 for discharging sea water or water and flow draws the gas in the regeneration column 180 by utilizing the flow of sea water or water flowing through the cooling water discharge line 134 to dissolve the flow drawn gas into the sea water or water, thereby promoting the energy saving as system. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a carbon dioxide recovery system and a carbon dioxide recovery method for recovering carbon dioxide and the like contained in exhaust gas from a boiler, a waste incinerator, and the like of a thermal power plant.

  In recent years, the problem of global warming due to the greenhouse effect of carbon dioxide, which is a combustion product of fossil fuel, has been increasing. In the Kyoto Protocol of the United Nations Framework Convention on Climate Change, Japan's goal of reducing greenhouse gas emissions is to achieve the 1990 ratio of minus 6% between 2008 and 2012.

  Against this background, a system for recovering carbon dioxide by using, for example, an aqueous solution of an amine compound, which is an alkaline substance, as an absorbing solution is proposed. (For example, refer to Patent Document 1).

  Here, FIG. 3 shows an outline of a conventional carbon dioxide recovery system 200 that recovers carbon dioxide using an aqueous amine solution as an absorbing solution.

  In the conventional carbon dioxide recovery system 200 shown in FIG. 3, exhaust gas 201 discharged by burning fossil fuel is guided to an absorption tower 203 by a gas blower 202. An absorption liquid 204 having a temperature of about 50 ° C. is supplied to the upper portion of the absorption tower 203, and the supplied absorption liquid 204 comes into contact with the introduced exhaust gas 201 and absorbs carbon dioxide in the exhaust gas 201. On the other hand, the remaining exhaust gas 201 having absorbed the carbon dioxide in the absorbing liquid 204 is released from the upper part of the absorption tower 203 to the atmosphere.

  The absorption liquid 204 that has absorbed carbon dioxide is extracted from the lower part of the absorption tower 203 and guided to the heat exchanger 206 by the pump 205 and further to the regeneration tower 207.

  The absorbing liquid 204 guided to the regeneration tower 207 is heated to a temperature of about 120 ° C. by the steam 209 of the heater 208 and disturbed. Then, carbon dioxide is dissipated from the absorbing liquid 204 and regenerated into the absorbing liquid 204 that can absorb carbon dioxide again. The regenerated absorption liquid 204 is returned to the upper part of the absorption tower 203 by the circulation pump 210 through the heat exchanger 206 and the cooler 211. On the other hand, the carbon dioxide released from the absorbing liquid 204 is guided to the separator 213 through the cooler 212, and is recovered after moisture is removed by the separator 213.

  In the conventional carbon dioxide recovery system 200 configured as described above, the absorption liquid 204 is regenerated in the regeneration tower 207 by heating the absorption liquid 204 to about 120 ° C. under almost atmospheric pressure.

In the conventional carbon dioxide recovery system 200 configured as described above, a large amount of heat energy is consumed to regenerate the absorbing liquid 204. Further, in the conventional carbon dioxide recovery system 200, the recovered carbon dioxide is pressurized and dissolved and fixed in seawater or river water, or is transported to a predetermined area of the sea or river, and is converted into seawater or river water. It was fixed.
JP 2002-126439 A

  In the conventional carbon dioxide recovery system 200 described above, in the regeneration tower 207, a large amount of circulating absorbent 204 is heated under atmospheric pressure to release carbon dioxide, thereby regenerating the absorbent 204. Therefore, in order to release carbon dioxide, it is necessary to heat the absorbing liquid 204 to a high temperature of about 120 ° C., and a large amount of high-temperature steam 209 is used, and it is difficult to improve the thermal efficiency of the system. Furthermore, the recovered carbon dioxide must be pressurized and dissolved and fixed in seawater and river water, or transported to a predetermined area in the sea and river and fixed in seawater and river water. There was a problem that a lot of energy had to be consumed.

  Accordingly, the present invention has been made to solve the above-described problems, and can efficiently reduce the pressure in the regenerator, and the carbon dioxide released from the regenerator can be dissolved directly in seawater or water. It is an object of the present invention to provide a carbon dioxide recovery system and a carbon dioxide recovery method that can be fixed and can save energy as a system.

  In order to achieve the above object, a carbon dioxide recovery system of the present invention comprises a gas inlet, an absorbing liquid inlet for absorption, a remaining gas outlet and an absorbent outlet, and a gas introduced from the gas inlet. An absorption device that causes gas-liquid contact with the absorption liquid introduced from the absorption liquid inlet for absorption and causes the absorption liquid to absorb carbon dioxide in the gas; an absorption liquid introduction port for regeneration; a regeneration absorption liquid discharge port; A regenerator comprising a carbon dioxide outlet and regenerating the absorbent by releasing carbon dioxide from the absorbent that has absorbed the carbon dioxide; and the regenerator for absorbing liquid discharged from an absorbent outlet of the absorber A first absorbing liquid line that leads to the regenerating absorbent inlet of the regenerating apparatus, and a second absorbing liquid that guides the absorbent discharged from the regenerating absorbent outlet of the regenerating apparatus to the absorbing absorbent inlet of the absorbing apparatus Line, seawater or A gas that is interposed in a drainage line that drains water and that uses the flow of seawater or water flowing through the drainage line to draw the gas in the regenerator and dissolve the drawn gas in the seawater or water. And a melting device.

  According to this carbon dioxide recovery system, carbon dioxide released from the absorbing liquid in the regenerator is drawn by using a flow of seawater or water by a gas dissolving device, and dissolved and fixed in seawater or water. Can do. Therefore, it is necessary to pressurize the recovered carbon dioxide and dissolve and fix it in seawater or river water, or transport the recovered carbon dioxide to a predetermined area of the sea or river and fix it to seawater or river water. Energy saving can be achieved.

  In the carbon dioxide recovery method of the present invention, the gas and the absorption liquid are guided to an absorption device, the gas and the absorption liquid are brought into gas-liquid contact, and the absorption liquid absorbs carbon dioxide in the gas; The regeneration liquid that has absorbed carbon dioxide in the absorption process is guided to a regenerator, the carbon dioxide is released from the absorption liquid to regenerate the absorption liquid, and the regeneration using the flow of seawater or water. A gas dissolving step of flowing the gas in the apparatus and dissolving the drawn gas in the seawater or the water.

  According to this carbon dioxide recovery method, carbon dioxide released from the absorbing solution in the regeneration process is drawn using seawater or water flow in the gas dissolution process, and dissolved and fixed in seawater or water. Can do. Therefore, it is necessary to pressurize the recovered carbon dioxide and dissolve and fix it in seawater or river water, or transport the recovered carbon dioxide to a predetermined area of the sea or river and fix it to seawater or river water. Energy saving can be achieved.

  According to the carbon dioxide recovery system and the carbon dioxide recovery method of the present invention, the pressure in the regenerator can be efficiently reduced, and the carbon dioxide released from the regenerator is directly dissolved and fixed in seawater or water. Energy saving as a system can be promoted.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows an outline of a carbon dioxide recovery / thermal power generation system in which a thermal power generation system 20 includes a carbon dioxide recovery system 10 according to an embodiment of the present invention.

  The thermal power generation system 20 is mainly composed of a boiler 100, a steam turbine 110, a generator 120, and the like.

  One end of a working fluid supply line 130 that supplies working fluid such as steam to the steam turbine 110 is connected to the boiler 100. The other end of the working fluid supply line 130 is connected to, for example, a high-temperature steam supply port of the steam turbine 110. In addition, the steam turbine 110 is an operation for returning, to the boiler 100, the steam that has been expanded by the steam turbine 110 or the steam that has been expanded by the steam turbine 110, for example, condensed through a condenser. One end of the fluid recovery line 131 is connected. The other end of the working fluid recovery line 131 is connected to the boiler 100.

  Further, one end of a gas discharge line 132 is connected to the boiler 100. The other end of the gas exhaust line 132 is connected to the exhaust heat recovery unit 140. The exhaust heat recovery device 140 is connected to the gas blower 150. Further, an air intake 101 for taking in combustion air is provided at the lower part of the boiler 100.

  One end of a cooling water supply line 133 that supplies, for example, seawater or water to the steam turbine 110 as cooling water is connected to the steam turbine 110. The steam turbine 110 is connected to one end of a cooling water discharge line 134 that guides cooling water discharged from the steam turbine 110 via a liquid feed pump 160 and a gas dissolving device 145. Here, the other end of the cooling water supply line 133 and the other end of the cooling water discharge line 134 reach the sea when, for example, seawater is used as the cooling water. For example, when river water is used as the cooling water. There is a river. In addition to these, for example, when a system including the carbon dioxide recovery system 10 is constructed near the lake and the lake water is used as the cooling water, the other end of the cooling water supply line 133 and the cooling water discharge line are used. The other end of 134 is arranged to reach the lake.

  Next, the carbon dioxide recovery system 10 mainly includes an absorption tower 170, a regeneration tower 180, a control unit 146, and the like. In FIG. 1, the control unit 146 is electrically connected to each pump, each component device, and the like, which will be described later, but description of connection lines is omitted for clarity of the drawing.

  Under the absorption tower 170, an exhaust gas inlet 171 is provided for guiding the exhaust gas 105 containing carbon dioxide discharged from the boiler 100 and heat recovered by the exhaust heat recovery device 140 into the absorption tower 170. The gas introduced into the exhaust gas inlet 171 is not limited to the exhaust gas 105 discharged from a boiler of a thermal power plant, a municipal waste incinerator, or the like, for example, natural gas containing carbon dioxide mined at a natural gas mining site But you can. When this natural gas is introduced into the absorption tower 170, carbon dioxide can be separated from the natural gas, so that a high concentration of natural gas can be recovered.

  The exhaust gas inlet 171 is connected to a gas blower 150 for sending the exhaust gas 105 into the absorption tower 170. In the upper part of the absorption tower 170, an absorption liquid inlet 172 for absorption for introducing the absorption liquid 106 discharged from the regeneration absorption liquid outlet 181 of the regeneration tower 180 is provided. The absorption liquid inlet 172 for absorption is provided with an absorption liquid ejection part 173 that ejects the absorption liquid 106. Further, inside the absorption tower 170, a filler 174 that mainly brings gas-liquid contact between the absorption liquid 106 ejected from the absorption liquid ejection section 173 and the exhaust gas 105 introduced into the absorption tower 170 is installed. The upper end of the absorption tower 170 functions as a remaining gas discharge port and is provided with an exhaust port 175 for exhausting the exhaust gas 105 having absorbed carbon dioxide into the atmosphere by passing through the filler 174. ing.

  Here, it is preferable that the absorbing liquid 106 ejected from the absorbing liquid ejecting section 173 is ejected uniformly. For example, the absorbing liquid ejecting section 173 is provided with a spray nozzle or the like capable of obtaining a predetermined spray particle size and spray pattern. It may be used. If the absorption liquid 106 can be dispersed substantially uniformly in the absorption tower 170 by the configuration of the absorption liquid introduction port 172 for absorption, the absorption liquid ejection part 173 may not be provided.

  For example, the filler 174 may be any material that has a porous structure, a honeycomb structure, or the like and has an action of disturbing the absorbent 106 that passes through the filler 174. Moreover, the filler 174 may be installed in the absorption tower 170 in multiple stages. When the fillers 174 are installed in multiple stages, for example, an absorbing liquid ejection part 173 that ejects the absorbing liquid 106 may be provided corresponding to each stage. If the gas-liquid contact between the exhaust gas 105 and the absorption liquid 106 can be efficiently performed in the absorption tower 170, the absorption tower 170 can be configured without installing the filler 174.

  Further, an absorption liquid discharge port 176 for discharging the absorption liquid 106 that has absorbed carbon dioxide is provided at the bottom of the absorption tower 170. The absorption liquid discharge port 176 is connected to one end of an absorption liquid line 135 provided with a liquid feed pump 161. The other end of the absorbent liquid line 135 is connected to the regeneration absorbent inlet 182 of the regeneration tower 180.

  A regeneration absorption liquid discharge port 181 for discharging the regenerated absorption liquid 106 is provided at the bottom of the regeneration tower 180. The regeneration absorbing liquid discharge port 181 is connected to one end of an absorbing liquid line 137 provided with a liquid feed pump 162 and a cooler 136. The other end of the absorption liquid line 137 is connected to the absorption liquid inlet 172 for absorption of the absorption tower 170. The cooler 136 cools the absorbing liquid 106 that circulates through the absorbing liquid line 137 and includes a heat exchanger or the like. In the cooler 136, for example, seawater or water may be used as a cooling medium for recovering heat from the absorbing liquid 106.

  In addition, a carbon dioxide outlet 184 is provided in the upper part of the regeneration tower 180, and carbon dioxide in the regeneration tower 180 is supplied to the gas dissolving device 145 interposed in the cooling water discharge line 134 at the carbon dioxide outlet 184. One end of the leading carbon dioxide lead line 138 is connected. On the other hand, the other end of the carbon dioxide derivation line 138 is connected to the intake hole of the gas dissolving device 145.

  In addition, the regeneration tower 180 is provided with a heater 183 that heats the absorbing liquid 106 accumulated at the bottom using, for example, the heat of the exhaust gas 105. For the regeneration tower 180, for example, a flushing tank or a tank provided with a filler as in the absorption tower 170 is used. Further, when supplying the absorbing liquid 106 into the regeneration tower 180, for example, it is preferable to atomize the absorbing liquid 106 and supply it into the regeneration tower 180. In this case, it is preferable to provide an absorbing liquid ejection section (not shown) for atomizing the absorbing liquid 106 at the upper portion of the regeneration tower 180. The absorbing liquid jetting unit is configured by, for example, a spray nozzle, a pressure jet nozzle, a nozzle having a configuration in which an intake hole of a gas dissolving device 145 described later is closed. In addition, the structure of an absorption liquid ejection part is not restricted to these, What is necessary is just to have a mechanism in which the absorption liquid 106 is atomized.

  As described above, a reflux path for refluxing the absorption liquid 106 is formed in the order of the absorption tower 170, the absorption liquid line 135, the regeneration tower 180, the absorption liquid line 137, and the absorption tower 170.

  The liquid feed pumps 161 and 162 operate based on signals from the control unit 146 to adjust the flow rate of the absorbent 106 flowing in the absorbent liquid lines 135 and 137, and the like.

  Here, the gas dissolving device 145 interposed in the cooling water discharge line 134 for guiding the cooling water discharged from the steam turbine 110 will be described with reference to FIG. Here, the case where the cooling water discharged from the steam turbine 110 is seawater will be described.

  FIG. 2 is a cross-sectional view showing an example of the configuration of the gas dissolving device 145. As shown in FIG. 2, the gas dissolving device 145 mainly includes a liquid channel 190 through which seawater from the cooling water discharge line 134 flows and a gas channel 191 that guides the gas drawn into the liquid channel 190. It is configured. The liquid flow path 190 has a structure in which the cross-sectional area is gradually decreased in the direction in which the liquid flows to form the nozzle portion 190a, and the cross-sectional area is gradually increased on the downstream side. The gas channel 191 is configured to communicate with the liquid channel 190 immediately downstream of the nozzle portion 190 a of the liquid channel 190.

  Since this gas dissolving device 145 is interposed in the cooling water discharge line 134, seawater flowing through the cooling water discharge line 134 flows into the gas dissolving device 145 from the liquid introduction hole 192 and passes through the liquid flow path 190. . Seawater that passes through the nozzle portion 190a of the liquid flow path 190 becomes a jet, and the gas from the regenerator 180 is drawn from the intake hole 193 through the gas flow path 191 to the jet by the flow action of the jet. In particular, the carbon dioxide drawn from the regeneration tower 180 by the jet of seawater is rapidly mixed with seawater in the gas dissolving device 145 and dissolved in seawater. In addition, some carbon dioxide may be dissolved while flowing through the cooling water discharge line 134 together with seawater after passing through the gas dissolving device 145. And the seawater which melt | dissolved the carbon dioxide flows through the cooling water discharge line 134, for example, is discharged | emitted in the sea. Further, in this gas dissolving device 145, the inside of the regeneration tower 180 is decompressed in order to draw the gas in the regeneration tower 180. By this gas dissolving device 145, the inside of the regeneration tower 180 can be depressurized to 20 to 80 kPa with absolute pressure.

  Here, in order to efficiently dissolve the gas such as carbon dioxide drawn from the regeneration tower 180 into the seawater, for example, swirling into the seawater flowing through the liquid channel 190 on the upstream side of the nozzle portion 190a of the liquid channel 190 May be provided. In addition, the structure of the gas dissolving apparatus 145 is not restricted to an above-described structure, What is necessary is just what can exhibit an above-described effect.

  Specific examples of the apparatus having the configuration of the gas dissolving device 145 described above include an aspirator (water flow pump). Here, the number of the gas dissolving devices 145 interposed in the cooling water discharge line 134 is not particularly limited, and is appropriately set according to the application and operating conditions. When a plurality of gas dissolving devices 145 are installed, the other end of the carbon dioxide derivation line 138 is configured to branch corresponding to the intake holes of each gas dissolving device 145.

  Here, the case where the cooling water discharged from the steam turbine 110 is seawater has been described, but the same effect can be obtained when the cooling water is water.

  Next, the absorbing liquid 106 will be described.

  Sodium carbonate or potassium carbonate can be used as the main solute of the absorbing liquid 106.

  When sodium carbonate is used as the main solute, an absorbing solution 106 in which 10 to 28 g of sodium carbonate is dissolved per 100 g of water and the weight concentration is adjusted to 9 to 22% is used.

  In this case, the temperature of the absorbing liquid 106 in the absorption tower 170 is set to 40 to 75 ° C., and the temperature of the absorbing liquid 106 in the regeneration tower 180 is set to 60 to 90 ° C.

  Here, the temperature of the absorption liquid 106 in the absorption tower 170 was set in the range of 40 to 75 ° C. The reason why the absorption liquid 106 containing sodium carbonate as a main solute was less than 40 ° C. This is because carbon absorption is slow, and when it exceeds 75 ° C., carbon dioxide absorbed in the absorption liquid 106 starts to be dissipated in the absorption tower 170.

  In addition, the temperature of the absorbing liquid 106 in the regeneration tower 180 is set in the range of 60 to 90 ° C., when the absorbing liquid 106 mainly containing sodium carbonate is less than 60 ° C., the release of carbon dioxide is slow. This is because when the temperature exceeds 90 ° C., a large amount of moisture disappears from the absorbing liquid 106.

  On the other hand, when potassium carbonate is used as the main solute, an absorbing solution 106 in which 10 to 43 g of potassium carbonate is dissolved per 100 g of water and the weight concentration is adjusted to 9 to 30% is used.

  In this case, the temperature of the absorbing liquid 106 in the absorption tower 170 is set to about 40 to 75 ° C., and the temperature of the absorbing liquid 106 in the regeneration tower 180 is set to about 70 to 95 ° C.

  Here, the temperature of the absorption liquid 106 in the absorption tower 170 was set to 40 to 75 ° C. when the temperature of the absorption liquid 106 containing potassium carbonate as a main solute was lower than 40 ° C., carbon dioxide to the absorption liquid 106. This is because a large amount of water disappears from the absorbing liquid 106 when the absorption of the water becomes slower and the temperature exceeds 75 ° C. In addition, the temperature of the absorbent 106 in the regeneration tower 180 is set to 70 to 95 ° C. When the temperature of the absorbent 106 having potassium carbonate as the main solute is lower than 70 ° C., the release of carbon dioxide is delayed, This is because when the temperature exceeds 95 ° C., a large amount of water vapor is generated from the absorbing liquid 106.

  Next, the operation of the carbon dioxide recovery system 10 will be described.

  The exhaust gas 105 discharged from the boiler 100 is supplied into the absorption tower 170 by the gas blower 150. When the exhaust gas 105 is supplied into the absorption tower 170, the absorption liquid 106 is ejected from the absorption liquid ejection section 173 at the top of the absorption tower 170 via the absorption liquid line 137. In the absorption tower 170, the absorbing liquid 106 and the exhaust gas 105 come into gas-liquid contact, and the absorbing liquid 106 absorbs carbon dioxide contained in the exhaust gas 105. Further, the remaining exhaust gas including nitrogen and carbon dioxide that has not been absorbed is released into the atmosphere from the exhaust port 175 of the absorption tower 170.

  The absorbing liquid 106 that has absorbed carbon dioxide is introduced into the regeneration tower 180 from the regeneration absorbing liquid inlet 182 of the regeneration tower 180 by the liquid feed pump 161 via the absorbent liquid line 135. The inside of the regeneration tower 180 is in a reduced pressure state of 20 to 80 kPa in absolute pressure, and the absorbing liquid 106 releases the absorbed carbon dioxide. At this time, a part of the absorbing liquid 106 stored at the bottom of the regeneration tower 180 is heated by the heater 183 to generate water vapor. The water vapor flows from the lower part to the upper part of the regeneration tower 180 and comes into gas-liquid contact with the absorbing liquid 106 from the upper part. By this contact, the carbon dioxide absorbed in the absorbing liquid 106 is released into the water vapor, and the absorbing liquid 106 is regenerated. Note that carbon dioxide is released from the absorbing liquid 106 by contact with water vapor, but in addition to this, carbon dioxide is also released from the absorbing liquid 106 when the inside of the regeneration tower 180 is depressurized. A part of the absorbing liquid 106 stored at the bottom of 180 generates water vapor.

  Further, the regenerated absorption liquid 106 stored at the bottom of the regeneration tower 180 is passed through the absorption liquid line 137 by the liquid feed pump 162 from the absorption liquid inlet 172 for absorption in the absorption tower 170. Then, the carbon dioxide absorption process described above is performed again. When the temperature of the absorbing liquid 106 flowing through the absorbing liquid line 137 is high, the absorbing liquid 106 is cooled by the cooler 136 interposed in the absorbing liquid line 137. Further, the flow rate of the refrigerant in the cooler 136 is adjusted based on a signal from the control unit 146, for example.

  On the other hand, carbon dioxide or the like released into the regeneration tower 180 is guided to the intake hole 193 of the gas dissolving device 145 by the flowing action of seawater flowing through the gas dissolving device 145. And it is guide | induced to the cooling water discharge line 134 with the seawater which flows through the gas dissolving apparatus 145. FIG. Since carbon dioxide and the like are drawn by the gas dissolving device 145 and guided to the cooling water discharge line 134, the inside of the regeneration tower 180 is depressurized and a predetermined depressurized state can be maintained. Note that what is drawn from the regeneration tower 180 may include, for example, water droplets formed by condensation of water vapor in the regeneration tower 180 in addition to carbon dioxide and water vapor.

  The carbon dioxide flowed to the gas dissolving device 145 is rapidly mixed with seawater, dissolved in seawater, and fixed. In addition, after passing through the gas dissolving device 145, some carbon dioxide may be dissolved while flowing in the cooling water discharge line 134 together with seawater. And the seawater which melt | dissolved the carbon dioxide flows through the cooling water discharge line 134, for example, is discharged | emitted in the sea. Further, for example, by discharging seawater in which carbon dioxide discharged from the cooling water discharge line 134 is dissolved into the open sea, carbon dioxide dissolved in seawater can be prevented from affecting the natural world.

  As described above, in the carbon dioxide recovery system 10 according to the embodiment, since the pressure in the regeneration tower 180 can be reduced by the gas dissolving device 145, the pressure in the regeneration tower 180 is reduced using a vacuum pump or the like. Compared to the case, the energy required for decompression in the regeneration tower 180 can be greatly reduced. Further, since the pressure in the regeneration tower 180 can be reduced by the gas dissolving device 145, the heating temperature of the absorbent 106 in the regeneration tower 180 can be lowered, and the regeneration energy of the absorbent 106 can be reduced.

  Furthermore, since the carbon dioxide released from the absorbing liquid 106 in the regeneration tower 180 can be drawn out by the gas dissolving device 145 and dissolved in seawater or the like, it can be fixed by pressurizing the recovered carbon dioxide. There is no need to dissolve and fix in river water or transport the recovered carbon dioxide to a predetermined area of the sea or river and fix it in sea water or river water, thus saving energy. For example, when the cooling water of the steam turbine 110 is used as the cooling water flowing through the cooling water discharge line 134, a large amount of seawater is used, so that a large amount of carbon dioxide can be dissolved and fixed.

  Furthermore, since the carbon dioxide recovery system 10 can recover a large amount of carbon dioxide discharged from a thermal power plant without using excessive energy, it can contribute to prevention of global warming.

  In the above-described embodiment, an example in which the gas dissolving device 145 is interposed with the cooling water discharge line 134 is shown. However, the gas dissolving device 145 is further used as a refrigerant of the cooler 136 using seawater or water as a refrigerant. It may be interposed in the return pipe.

  In the above-described embodiment, an example in which the carbon dioxide recovery system 10 of the present invention is adopted for the thermal power generation system 20 is shown. However, the use of the carbon dioxide recovery system of the present invention is not limited to this. Absent. For example, it can be employed in municipal waste incineration plants and natural gas mining plants, and can also be employed in ship power systems.

The schematic diagram which shows the carbon dioxide collection system of embodiment of this invention. Sectional drawing which shows an example of a structure of a gas dissolving apparatus. Schematic diagram showing a conventional carbon dioxide recovery system.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Carbon dioxide recovery system, 20 ... Thermal power generation system, 100 ... Boiler, 105 ... Exhaust gas, 106 ... Absorption liquid, 110 ... Steam turbine, 120 ... Generator, 133 ... Cooling water supply line, 134 ... Cooling water discharge line, 135, 137 ... Absorbing liquid line, 138 ... Carbon dioxide outlet line, 145 ... Gas dissolving device, 146 ... Control unit, 150 ... Gas blower, 170 ... Absorption tower, 180 ... Regeneration tower.

Claims (5)

A gas introduction port, an absorption liquid introduction port for absorption, a remaining gas discharge port and an absorption liquid discharge port are provided, and the gas introduced from the gas introduction port and the absorption liquid introduced from the absorption liquid introduction port for absorption are gas-liquid. An absorption device that makes the absorption liquid absorb carbon dioxide in the gas,
A regeneration device comprising a regeneration absorbent inlet, a regeneration absorbent outlet, and a carbon dioxide outlet, and regenerating the absorbent by releasing carbon dioxide from the absorbent that has absorbed the carbon dioxide;
A first absorbing liquid line for guiding the absorbing liquid discharged from the absorbing liquid discharge port of the absorbing apparatus to the regenerating absorbing liquid inlet of the regenerating apparatus;
A second absorption liquid line for guiding the absorption liquid discharged from the regeneration absorption liquid discharge port of the regeneration apparatus to the absorption liquid introduction port for absorption of the absorption apparatus;
Intervene in a drainage line for draining seawater or water, and use the flow of seawater or water flowing through the drainage line to draw the gas in the regenerator and dissolve the drawn gas in the seawater or water. A carbon dioxide recovery system comprising: a gas dissolving device.   The carbon dioxide recovery system according to claim 1, wherein the gas dissolving device includes an aspirator.   The carbon dioxide recovery system according to claim 1 or 2, wherein the gas is a natural gas containing exhaust gas from a boiler, an incinerator, or mined carbon dioxide.   The carbon dioxide recovery system according to any one of claims 1 to 3, wherein the seawater or the water is steam turbine cooling water. An absorption step of guiding the gas and the absorption liquid to an absorption device, bringing the gas and the absorption liquid into gas-liquid contact, and allowing the absorption liquid to absorb carbon dioxide in the gas;
A regenerating step of regenerating the absorbing solution by guiding the absorbing solution that has absorbed carbon dioxide in the absorbing step to a regenerating device, releasing the carbon dioxide from the absorbing solution;
A carbon dioxide recovery process comprising: a gas dissolving step of flowing a gas in the regenerator using a flow of seawater or water and dissolving the drawn gas in the seawater or the water. Method.

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