JP5404682B2 - CO2 recovery device and CO2 absorbent regenerator - Google Patents

Description

The present invention relates to a CO ₂ recovery apparatus and a CO ₂ absorbing solution regeneration device having improved thermal degradation inhibition of the CO ₂ absorbing liquid.

Currently used fossil fuels such as petroleum, coal, and natural gas are mainly composed of carbon and hydrogen, so if they are burned to obtain energy, the generation of carbon dioxide (CO ₂ ) can be avoided. Absent. The consumption of fossil fuels is increasing year by year, and the accompanying increase in CO ₂ emissions is one of important energy and environmental issues.

Conventionally, as a measure for reducing CO ₂ , various studies have been made on CO ₂ recovery technology for efficiently recovering CO ₂ contained in exhaust gas and CO ₂ immobilization technology for immobilizing recovered CO ₂ . . In particular, CO as the ₂ capture technology, the exhaust gas and an amine CO ₂ absorbing solution containing CO ₂ (hereinafter, CO of ₂ absorbing solution) and that to absorb the CO ₂ in contact with a CO ₂ absorbing solution, Many studies have been made on techniques for recovering CO ₂ in exhaust gas.

The CO ₂ recovery apparatus, for example, Patent Document 1, heating the absorber contacting the exhaust gas and the CO ₂ absorbing solution containing CO _2, the CO ₂ absorbent having absorbed CO _2, CO ₂ removal to consist reproducing apparatus for reproducing, it shall be reused by circulating again absorber of CO ₂ absorbing solution regenerated by removing the CO ₂ from the reproduction apparatus is disclosed.

Japanese Patent No. 3364103 (paragraph 0006, FIG. 1 and FIG. 2)

However, the conventional CO ₂ recovery device and the CO ₂ absorbent regenerator have a process problem that the thermal degradation of the CO ₂ absorbent tends to occur.

The present invention inhibit the thermal deterioration of the CO ₂ absorbing solution CO ₂ recovery apparatus and a CO ₂ absorbing solution regeneration apparatus (hereinafter, referred reproducing apparatus) and to provide a.

As a result of diligent research to solve the above problems, the present inventors have found that it is extremely effective to set the temperature of the absorbing liquid to 100 ° C. or higher and 120 ° C. or lower in order to suppress thermal deterioration of the absorbing liquid. I found it. It should be noted that the CO ₂ absorption liquid that has absorbed CO ₂ by the absorption device is a “rich solution”, the CO ₂ absorption solution that has been regenerated by removing CO ₂ to a low concentration by the regeneration device is the “lean solution”, and the CO ₂ is recovered by the regeneration device. The CO ₂ absorbent that has been partially removed and regenerated is referred to as a “semi-lean solution”. Further, the thermal deterioration of the CO ₂ absorbing liquid occurs particularly when the CO ₂ absorbing liquid that has reached a high temperature in the regenerator is temporarily stored in a predetermined place. refers to a phenomenon that degradation products in part does not function as a CO ₂ absorbing solution by generation of CO ₂ absorbing solution.

To solve the problems described above, the present invention is absorbed and the absorption device for removing CO ₂ in the gas contacting the gas and the CO ₂ absorbing liquid containing CO _2, the CO ₂ in the absorber A regenerator that removes and regenerates CO ₂ in the rich solution that is the CO ₂ absorbent, a rich solution supply passage that supplies the rich solution from the absorber to the regenerator, and the absorber from the regenerator in the lean-solution supply passage for supplying the lean solution which is the CO ₂ absorbing solution from which CO ₂ has been removed, the inside of the reproducing apparatus, reproducing space and the lean solution temporarily the removal of CO ₂ of the rich solution Sorting means for dividing into a storage space to be stored, a lean solution recirculation passage for extracting the lean solution in the regeneration space and returning it to the storage space, and the lean solution passing through the lean solution recirculation passage A CO ₂ recovery apparatus characterized by having a means for heat exchange between the low temperature of the medium than the lean solution.

  Thereby, the temperature of the lean solution in the regeneration space is once lowered outside the regeneration device and then returned to the storage space, and as a result, the temperature of the lean solution is lower than that of the lean solution in the regeneration space. The lean solution can be stored in the lean solution storage unit, and an effect of suppressing thermal deterioration of the lean solution can be obtained.

According to the present invention, in the present invention, the means for exchanging heat with the medium having a temperature lower than that of the lean solution is a first rich / lean heat for exchanging heat between the lean solution and the rich solution passing through the rich solution supply passage. A CO ₂ recovery device characterized by being an exchanger.

  Thereby, the lean solution in the regeneration space is once taken out of the regeneration device, heat-exchanged with the rich solution to cool the lean solution, and then returned to the storage space again. As a result, the lean solution having a temperature lower than that of the lean solution in the regeneration space can be stored in the lean solution storage unit, and an effect of suppressing thermal deterioration of the lean solution can be obtained. In addition, the rich solution is heated, and an effect of bringing the rich solution to an appropriate temperature when supplied to the regenerator can be obtained.

In the present invention, in the present invention, the means for exchanging heat with a medium having a temperature lower than that of the lean solution is a semi-lean / lean heat for exchanging heat between the lean solution and a semi-lean solution from which CO ₂ has been partially removed in the regeneration space. A CO ₂ recovery device characterized by being an exchanger.

  Thereby, the lean solution in the regeneration space is once extracted out of the regeneration device, heat-exchanged with the semi-lean solution, and the temperature of the lean solution is lowered, and then returned to the storage space. As a result, the lean solution having a temperature lower than that of the lean solution in the regeneration space can be stored in the lean solution storage unit, and an effect of suppressing thermal deterioration of the lean solution can be obtained. Moreover, the temperature of the semi-lean solution is raised and an effect of bringing the temperature to an appropriate temperature when supplied to the regenerator again can be obtained.

In the present invention, the rich solution supply passage includes the rich solution and the lean solution passing through the lean solution supply passage between the absorption device and the first rich / lean heat exchanger. A CO ₂ recovery device provided with a second rich / lean heat exchanger for exchanging heat.

  Thereby, the lean solution in the regeneration space is once taken out of the regeneration device, heat-exchanged with the rich solution to cool the lean solution, and then returned to the storage space again. As a result, the lean solution having a temperature lower than that of the lean solution in the regeneration space can be stored in the lean solution storage unit, and an effect of suppressing thermal deterioration of the lean solution can be obtained. In addition, compared with the case where only the first rich / lean heat exchanger is installed, the facilities of the first rich / lean heat exchanger and the second rich / lean heat exchanger can be reduced in size. An effect is obtained.

The present invention is the CO ₂ recovery apparatus according to the present invention, wherein the medium having a temperature lower than that of the lean solution is cooling water.

  Thereby, the lean solution in the regeneration space is once extracted out of the regeneration device, and after the heat is exchanged with the cooling water to cool the lean solution, the lean solution is returned to the storage space again. As a result, the lean solution having a temperature lower than that of the lean solution in the regeneration space can be stored in the lean solution storage unit, and an effect of suppressing thermal deterioration of the lean solution can be obtained.

The present invention is the CO ₂ recovery device according to the present invention, wherein a pressure control device for adjusting the pressure in the regenerator is provided.

  As a result, there is an action of reducing the pressure in the regenerator, and as a result, the rich solution can be regenerated into the lean solution at a temperature lower than usual, and the lean solution stored in the lean solution storage unit. The effect which suppresses the thermal degradation of is acquired.

The present invention removes the CO ₂ rich solution is CO ₂ absorbent having absorbed CO _2, the inside reproducing apparatus CO ₂ plays a lean solution which is the CO ₂ absorbing liquid that has been removed, the rich a dividing means for reproducing space and rie down reservoir for removing CO ₂ in the solution is divided into the storage space provided, and the lean solution return passage for returning to the storage space by extracting the lean solution of the reconstructed volume A CO ₂ absorbent regenerating apparatus comprising: means for exchanging heat between the lean solution passing through the lean solution reflux passage and a medium having a temperature lower than that of the lean solution.

  Thereby, the temperature of the lean solution in the regeneration space is once lowered outside the regeneration device and then returned to the storage space, and as a result, the temperature of the lean solution is lower than that of the lean solution in the regeneration space. The lean solution can be stored in the lean solution storage unit, and an effect of suppressing thermal deterioration of the lean solution can be obtained.

In the present invention, in the present invention, the means for exchanging heat with a medium having a temperature lower than that of the lean solution is a semi-lean / lean heat for exchanging heat between the lean solution and a semi-lean solution from which CO ₂ has been partially removed in the regeneration space. A CO ₂ absorbent regenerator characterized by being an exchanger.

  Thereby, the lean solution in the regeneration space is once extracted out of the regeneration device, heat-exchanged with the semi-lean solution, and the temperature of the lean solution is lowered, and then returned to the storage space. As a result, the lean solution having a temperature lower than that of the lean solution in the regeneration space can be stored in the lean solution storage unit, and an effect of suppressing thermal deterioration of the lean solution can be obtained. Moreover, the temperature of the semi-lean solution is raised and an effect of bringing the temperature to an appropriate temperature when supplied to the regenerator again can be obtained.

The present invention is the CO ₂ absorbent regenerator according to the present invention, wherein the medium having a temperature lower than that of the lean solution is cooling water.

  Thereby, the lean solution in the regeneration space is once extracted out of the regeneration device, and after the heat is exchanged with the cooling water to cool the lean solution, the lean solution is returned to the storage space again. As a result, the lean solution having a temperature lower than that of the lean solution in the regeneration space can be stored in the lean solution storage unit, and an effect of suppressing thermal deterioration of the lean solution can be obtained.

According to the present invention, the thermal deterioration of the CO ₂ absorbing solution to be circulated for reuse in the CO ₂ recovery apparatus can be suppressed.

1 is a schematic view of a CO ₂ recovery device according to Example 1. FIG. 1 is a schematic view of a chimney tray according to Example 1. FIG. It is the figure which showed the simulation result which computed the relationship between the absorption liquid thermal deterioration reduction rate and the temperature of the lean solution in a lean solution storage part. 3 is a schematic view of a CO ₂ recovery device according to Example 2. FIG. 6 is a schematic view of a CO ₂ recovery device according to Example 3. FIG. 6 is a schematic view of a CO ₂ recovery device according to Example 4. FIG. It is the figure which showed the relationship between the pressure in a reproducing | regenerating apparatus, and the temperature of a lean solution.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. In the following description, when the upper and lower sides of a component are specified and described, the direction in which the gravity of the component acts is the downward direction, and the opposite direction is the upward direction.

FIG. 1 is a schematic view of a CO ₂ recovery apparatus according to Embodiment 1 of the present invention. FIG. 2 is a schematic view of a chimney tray that is a part of the reproducing apparatus according to the first embodiment of the present invention. Further, FIG. 3 is a diagram showing a simulation result in which the relationship between the absorption liquid thermal deterioration reduction rate and the temperature of the lean solution in the lean solution storage part which is a part of the regenerator is calculated. The CO ₂ recovery apparatus 1000 will be described with reference to FIG.

The CO ₂ recovery apparatus 1000 according to the first embodiment includes an absorption device 20 that removes CO ₂ in exhaust gas, a regeneration device 30 that removes CO ₂ in a rich solution, and an exhaust gas supply passage that supplies exhaust gas to the absorption device 20. 100, a rich solution supply passage 101 that supplies a rich solution to the regeneration device 30, and a lean solution supply passage 102 that supplies a lean solution to the absorption device 20.

The absorption device 20 includes a CO ₂ absorption unit 21 including a packed bed in order from the top, and a rich solution storage unit 22 that temporarily stores the rich solution FL_r.

  The regenerator 30 includes a recovery unit 31 including a packed bed in order from above, a chimney tray 33 that recovers the lean solution FL_l immediately after passing through the recovery unit 31, and a lean solution storage unit 32 that temporarily stores the lean solution FL_l. Is provided. Here, as shown in FIG. 2, the chimney tray 33 includes a concave portion 33a for facilitating introduction of the lean solution FL_l into the extraction port 103A, and a cap portion 33c provided with a predetermined gap 33b. Further, the regenerator 30 is provided with a lean solution regenerative heating and reflux passage 103 that once extracts the lean solution FL_l in the regenerator 30 out of the regenerator 30 and returns it to the regenerator 30 again. Here, the lean solution regeneration heating reflux passage 103 includes an extraction port 103A provided between the recovery unit 31 and the chimney tray 33, and a return port 103B provided between the chimney tray 33 and the lean solution storage unit 32. Connect. Further, the lean solution regeneration heating reflux passage 103 is provided with a regeneration heater 50 for exchanging heat with high-temperature saturated steam S. In the regeneration heater 50, the lean solution FL_l in the lean solution regeneration heating reflux passage 103 is heat-exchanged by the high-temperature saturated steam S and heated for regeneration.

  The exhaust gas supply passage 100 connects the cooling device 10 and the absorption device 20, the rich solution supply passage 101 connects the absorption device 20 and the regeneration device 30, and the lean solution supply passage 102 connects the regeneration device 30 and the absorption device. 20 is connected.

For example, the exhaust gas G cooled to about 40 ° C. by the cooling device 10 passes through the exhaust gas supply passage 100 and is introduced into the lower portion of the absorber 20. The exhaust gas G introduced into the absorption device 20 comes into countercurrent contact with the lean solution FL_l at the CO ₂ absorption unit 21, whereby CO ₂ is removed. Here, the lean solution FL_l is supplied from the upper part of the absorber 20 through the lean solution supply passage 102. At this time, the temperature of the lean solution FL_l is, for example, around 60 ° C. The exhaust gas G ^* from which CO ₂ has been removed is released from the upper part of the absorber 20 to the outside of the CO ₂ recovery apparatus 1000. On the other hand, CO ₂ absorbent having absorbed CO ₂ in a CO ₂ absorbing section 21, temporarily is accumulated in the rich solution storage part 22 becomes rich solution FL_r. The temperature of the rich solution FL_r at this time is, for example, around 50 ° C.

The rich solution FL_r in the rich solution storage unit 22 is supplied to the upper part of the regenerator 30 through the rich solution supply passage 101. The rich solution FL_r supplied to the regenerator 30 undergoes an endothermic reaction in the recovery unit 31 to remove CO ₂ to become a lean solution FL_l. The CO ₂ separated from the rich solution FL_r is recovered from an upper part of the regenerator 30 to an apparatus separate from the CO ₂ recovery apparatus 1000. On the other hand, the lean solution FL_l from which the CO ₂ has been removed by the recovery unit 31 is heated by the saturated steam S by the regeneration heater 50 through the lean solution regeneration heating reflux passage 103, and then temporarily stored in the lean solution storage unit 32. It is done. The rich solution FL_l in the lean solution storage unit 32 is supplied again to the upper part of the absorber 20 through the lean solution supply passage 102 and reused.

As described above, the CO ₂ recovery apparatus 1000 can circulate the CO ₂ absorbent by connecting the absorption apparatus 20 and the regeneration apparatus 30 with the rich supply passage 101 and the lean solution supply passage 102. Further, the lean solution FL_l regenerated by the regenerator 30 can be reused by the absorber 20.

The CO ₂ recovery apparatus 1000 includes a sorting unit that divides the regeneration apparatus 30 into a regeneration space 30a for removing CO ₂ in the rich solution FL_r and a storage space 30b for temporarily storing the lean solution FL_l. Here, as will be described later, the regeneration space 30a and the storage space 30b are spaces in the regeneration device 30, and a space for regenerating the rich solution FL_r into the lean solution FL_l and a space for storing the regenerated lean solution FL_l. It hits. The lean solution FL_l in the regeneration solution 30a is extracted and returned to the storage space 30b. The lean solution reflux passage 104 and the lean solution reflux passage 104 are provided with the lean solution FL_l and the rich solution supply passage in the lean solution reflux passage 104. The first rich / lean heat exchanger 41 that exchanges heat with the rich solution FL_r in 101 is provided.

Here, in this embodiment, a partition member 34 is provided as a sectioning means for partitioning the internal space of the playback device 30 into a playback space 30a and a storage space 30b. The partition member 34 is provided between the return port 103 </ b> B of the lean solution regeneration heating reflux path 103 and the lean solution storage unit 32. Thus, at a temperature different from the lean solution FL_l the CO ₂ becomes a high temperature is removed by heating saturated steam S in the reproduction space 30a, it may have been pooled lean solution FL_l the storage space 30b.

  The lean solution reflux passage 104 is provided between the return port 103B of the lean solution regeneration heating reflux passage 103 and the partition member 34, and between the partition member 34 and the lean solution storage section 32. The returned return port 104B is connected. Further, a first rich / lean heat exchanger 41 is installed in the lean solution reflux passage 104 and between the extraction port 104A and the return port 104B. As a result, the lean solution FL_l having a high temperature in the recovery unit 31 is once extracted out of the regenerator 30, and in the middle, the first rich / lean heat exchanger 41 and the rich solution FL_r having a lower temperature than the lean solution FL_l. After the temperature is reduced by heat exchange, the temperature is returned again to the regenerator 30.

As described above, in this embodiment, the partition member 34 is provided to divide the regeneration device 30 into the regeneration space 30a for removing the CO ₂ in the rich solution FL_r and the storage space 30b for temporarily storing the lean solution FL_l. I have to. Thus, at a temperature lower than the lean solution FL_l the CO ₂ becomes a high temperature is removed by heating saturated steam S in the reproduction space 30a, it may have been pooled lean solution FL_l the storage space 30b.

  In the present embodiment, a lean solution reflux passage 104 that connects the regeneration space 30a and the storage space 30b is provided, and the lean solution reflux passage 104 is provided between the extraction port 104A and the return port 104B. A lean heat exchanger 41 is provided. Thereby, the lean solution FL_l in the regeneration space 30a can be extracted out of the regeneration device 30 through the extraction port 104A. Then, the temperature of the lean solution FL_l supplied to the storage space 30b can be lowered by heat exchange with the rich solution FL_r having a temperature lower than that of the lean solution FL_l. Therefore, the temperature of the lean solution FL_l stored in the lean solution storage unit 32 is lower than the temperature of the lean solution FL_l immediately after passing through the recovery unit 31, and the thermal deterioration of the lean solution FL_l is reduced compared to the past. Can do.

  Further, in this embodiment, the rich solution FL_r and the lean solution supply passage 102 in the rich solution supply passage 101 are provided in the rich solution supply passage 101 between the absorber 20 and the first rich / lean heat exchanger 41. A second rich / lean heat exchanger 40 for exchanging heat with the lean solution FL_l therein is provided.

  After the rich solution FL_r in the rich solution supply passage 101 is extracted from the absorber 20, the second rich / lean heat exchanger 40 exchanges heat with the lean solution FL_l in the lean solution supply passage 102 to increase the temperature. . Thereafter, the heat is further exchanged with the lean solution FL_l in the lean solution reflux passage 104 by the first rich / lean heat exchanger 41 to further increase the temperature, and then supplied to the regenerator 30. On the other hand, the lean solution FL_l in the lean solution supply passage 102 is cooled by the second rich / lean heat exchanger 40 through heat exchange with the rich solution FL_r in the rich solution supply passage 101.

  Thereby, the rich solution FL_r in the rich solution supply passage 101 supplied from the absorption device 20 to the regeneration device 30 can be heated from, for example, about 50 ° C. to about 110 ° C. Further, the lean solution FL_l in the lean solution supply passage 102 supplied from the regenerator 30 to the absorber 20 can be lowered from, for example, about 120 ° C. to about 60 ° C. Furthermore, compared with the case where only the first rich / lean heat exchanger 41 is installed, the facilities of the first rich / lean heat exchanger 41 and the second rich / lean heat exchanger 40 can be reduced in size.

  Here, for example, the rich solution FL_r in the rich solution supply passage 101 that has passed through the second rich / lean heat exchanger 40 is about 105 ° C. Further, the rich solution FL_r that has passed through the recovery unit 31 in the regeneration space 30a is around 124 ° C., but is extracted from the regeneration device 30 by the lean solution reflux passage 104 and is around 105 ° C. in the first rich / lean heat exchanger 41. The temperature of the lean solution FL_l in the lean solution recirculation passage 104 when the heat is exchanged with the rich solution FL_r in the rich solution supply passage 101 and returned to the storage space 30b is about 115 ° C.

On the other hand, from the simulation results shown in FIG. 3, the absorption liquid thermal deterioration reduction rate is remarkable at a temperature of 120 ° C. or lower, and the reduction rate increases as the temperature becomes lower, and the absorption liquid thermal deterioration reduction rate at a temperature lower than 100 ° C. It can be seen that is moving at less than 40%. Here, the CO ₂ absorption liquid thermal deterioration reduction rate in FIG. 3 is 0% when the temperature of the lean solution FL_l is 124 ° C. Therefore, the temperature of the lean solution FL_l stored in the lean solution storage unit 32 is preferably set to 100 ° C. or more and 120 ° C. or less. In the present embodiment, for example, when the lean solution FL_l cooled to 115 ° C. is stored in the lean solution storage unit 32, the CO ₂ absorption liquid thermal deterioration is about 25 compared with the case where it is stored in the lean solution storage unit 32 at 124 ° C. % Reduction.

As described above, the CO ₂ recovery apparatus 1000 includes the dividing means for dividing the regeneration apparatus 30 into the regeneration space 30a and the storage space 30b, the lean solution reflux passage 104, and the first rich / lean heat exchanger 41. . As a result, the lean solution FL_l in the regeneration space 30a is once extracted out of the regeneration device 30, and after the heat exchange with the rich solution FL_r is performed to lower the temperature, the operation returns to the storage space 30b again. The lean solution FL_l having a temperature lower than that of the lean solution FL_l in the regeneration space 30a can be stored in the lean solution storage unit 32, and an effect of suppressing thermal deterioration of the lean solution FL_l is exhibited.

FIG. 4 is a schematic view of a CO ₂ recovery apparatus according to Embodiment 2 of the present invention. The CO ₂ recovery apparatus 1001 will be described with reference to FIG. Note that the members that overlap the structure of the CO ₂ recovery unit according to the first embodiment, description thereof will be omitted given the same reference numerals.

The CO ₂ recovery device 1001 has a first semi-lean solution reflux passage 105 and a second semi-lean solution reflux passage 106 that once extract the semi-lean solution FL_sl in the regeneration space 30_1a and return it to the regeneration space 30_1a again. Also, the first semi-lean / lean heat exchanger 41a for exchanging heat between the semi-lean solution FL_sl in the first semi-lean solution reflux passage 105 and the lean solution FL_l in the lean solution reflux passage 104, and the second semi-lean solution reflux passage 106 A second semi-lean / lean heat exchanger 41b that exchanges heat between the semi-liquid solution FL_sl and the lean solution FL_l in the lean solution reflux passage 104;

  Here, the reproducing apparatus 30_1 according to the present embodiment includes, in order from the top, the first collection unit 31_1, the first chimney tray 33_1, the second collection unit 31_2, the second chimney tray 33_2, and the third collection unit 31_3. A third chimney tray 33_3 is provided.

  The first semi-lean solution reflux passage 105 is provided between the first recovery unit 31_1 and the first chimney tray 33_1, the extraction port 105A, and between the first chimney tray 33_1 and the second recovery unit 31_2. The return port 105B is connected. A first semi-lean / lean heat exchanger 41a is installed in the first semi-lean solution reflux passage 105 and between the extraction port 105A and the return port 105B.

  The second semi-lean solution reflux passage 106 is provided between the second recovery unit 31_2 and the second chimney tray 33_2, and the extraction port 106A provided between the second chimney tray 33_2 and the third recovery unit 31_3. The return port 106B is connected. A second semi-lean / lean heat exchanger 41b is installed in the second semi-lean solution reflux passage 106 and between the extraction port 106A and the return port 106B.

Accordingly, the rich solution supplied from the rich solution supply passage 101 to the regenerator 30_1 is first subjected to partial removal of CO ₂ by the first recovery unit 31_1 to become the semi-lean solution FL_sl, and then the first semi-lean solution reflux passage 105. Is once extracted out of the playback device 30_1, and then returns to the playback device 30_1 again. Further, after part of the CO ₂ is removed by the second recovery unit 31_2, the semi-lean solution FL_sl is once extracted out of the regenerator 30_1 through the second semi-lean solution reflux passage 106, and then returns to the regenerator 30_1 again. This is repeated, and finally, all the CO ₂ is removed by the third recovery unit 31_3 to become the lean solution FL_l.

  The semi-lean solution FL_sl in the second semi-lean solution reflux path 106 is at a higher temperature than the semi-lean solution FL_sl in the first semi-lean solution reflux path 105. This is because the semi-lean solution FL_sl in the second semi-lean solution reflux passage 106 causes more endothermic reaction in the regeneration space 30_1a than the semi-lean solution FL_sl in the first semi-lean solution reflux passage 105. Further, the lean solution FL_l in the lean solution reflux passage 104 is at a higher temperature than any of the semi-lean solutions FL_sl in the first semi-lean solution reflux passage 105 and the second semi-lean solution reflux passage 106.

  As a result, the lean solution FL_l that has reached a high temperature in the third recovery unit 31_3 is introduced into the lean solution recirculation passage 104 from the extraction port 104A and extracted out of the regeneration space 30_1a. First, the second semi-lean / lean heat exchange is performed. The temperature is lowered by exchanging heat with the semi-lean solution FL_sl in the second semi-lean solution reflux passage 106 having a temperature lower than that of the lean solution FL_l in the vessel 41b. Next, the first semi-lean / lean heat exchanger 41a exchanges heat with the semi-lean solution FL_sl in the first semi-lean solution reflux passage 105, which is lower in temperature than the lean solution FL_l, and further lowers the temperature. Then, it reaches the return port 104B and is returned to the storage space 30_1b.

  As described above, in this embodiment, the second rich / lean heat exchanger 41b and the first rich / lean heat exchanger 41b are arranged in order from the extraction port 104A between the extraction port 104A and the return port 104B. A heat exchanger 41a is provided. Thereby, the lean solution FL_l extracted outside from the regeneration space 30_1a can be lowered by heat exchange with the semi-lean solution FL_sl that is lower in temperature than the lean solution FL_l. Accordingly, the temperature of the lean solution FL_l stored in the lean solution storage unit 32 is lower than the temperature of the lean solution FL_l immediately after passing through the third recovery unit 31_3, and the thermal deterioration of the lean solution FL_l is reduced as compared with the past. can do.

  Here, for example, the semi-lean solution FL_sl in the first semi-lean solution reflux passage 105 is about 101 ° C. Further, the semi-lean solution FL_sl in the second semi-lean solution reflux passage 106 is about 105 ° C. The lean solution FL_l that has passed through the third recovery unit 31_3 in the regeneration space 30_1a is around 124 ° C., but the lean solution FL_l extracted from the regenerator 30_1 through the lean solution reflux passage 104 is first a second semi-lean / lean. The temperature is lowered to around 112 ° C. with the heat exchanger 41b. Next, the temperature of the lean solution FL_l is lowered to around 106 ° C. by the first semi-lean / lean heat exchanger 41a.

According to the simulation result shown in FIG. 3, in this embodiment, for example, the lean solution FL_l cooled to 106 ° C. is stored in the lean solution storage unit 32, and compared with the case where it is stored in the lean solution storage unit 32 at 124 ° C. , CO ₂ absorbing solution thermal degradation is reduced by about 40%.

As described above, the CO ₂ recovery apparatus 1001 includes the first semi-lean solution reflux passage 105, the second semi-lean solution reflux passage 106, the first semi-lean / lean heat exchanger 41a, and the second semi-lean / lean heat exchanger 41b. To do. As a result, the lean solution FL_l in the regeneration space 30_1a is once extracted out of the regeneration device 30, heat-exchanged with the semi-lean solution FL_sl and cooled down, and then returned to the storage space 30_1b again. The lean solution FL_l having a temperature lower than that of the lean solution FL_l in the regeneration space 30_1a can be stored in the lean solution storage unit 32, and an effect of suppressing thermal deterioration of the lean solution FL_l is exhibited.

  The number of installed semi-lean solution supply passages, semi-lean / lean heat exchangers, recovery units, lean recovery mechanisms, etc. is not limited to the number of installations shown in this embodiment.

FIG. 5 is a schematic view of a CO ₂ recovery apparatus according to Embodiment 3 of the present invention. The CO ₂ recovery apparatus 1002 will be described with reference to FIG. Note that the members that overlap the structure of the CO ₂ recovery unit according to the first embodiment, description thereof will be omitted given the same reference numerals.

The CO ₂ recovery device 1002 has a pump Pcw that pumps up the cooling water CW, and a cooling water supply passage 108 for supplying the cooling water CW to the CO ₂ recovery device 1002. Moreover, it has a cooling water / lean heat exchanger 41c for exchanging heat between the lean solution FL_l in the lean solution reflux passage 104 and the cooling water CW.

  Here, the cooling water / lean heat exchanger 41c is installed between the extraction port 104A and the return port 104B of the lean solution reflux passage 104.

  As a result, the lean solution FL_l having a high temperature in the recovery unit 31 is introduced into the lean solution recirculation passage 104 from the extraction port 104A and extracted out of the regeneration space 30a, and in the middle, in the cooling water / lean heat exchanger 41c. The temperature is lowered by exchanging heat with the cooling water CW in the cooling water supply passage 108 as a medium having a temperature lower than that of the lean solution FL_l. Then, it reaches the return port 104B and is returned into the storage space 30b.

As described above, in this embodiment, the cooling water supply passage 108 for supplying the cooling water CW of the adjacent sea to the CO ₂ recovery device 1002 is installed, and the cooling water / lean heat exchanger 41c is further provided in the cooling water supply passage 108. Is provided. Thereby, the lean solution FL_l extracted outside from the regeneration space 30a can be cooled by heat exchange with the cooling water CW as a medium having a temperature lower than that of the lean solution FL_l. Therefore, the lean solution FL_l stored in the lean solution storage unit 32 can be cooled down more than the lean solution FL_l immediately after passing through the recovery unit 31, and the thermal deterioration of the lean solution FL_l can be reduced compared to the conventional case. it can.

  Here, for example, the temperature of the cooling water CW is around 20 ° C. In addition, the rich solution FL_r that has passed through the recovery unit 31 in the regeneration space 30a is around 124 ° C., but the lean solution FL_l extracted from the regeneration device 30 by the lean solution reflux passage 104 is the cooling water / lean heat exchanger 41c. At around 100 ° C.

According to the simulation result shown in FIG. 3, in this embodiment, for example, by storing the lean solution FL_l cooled to 100 ° C. in the lean solution storage unit 32, compared with the case of storing in the lean solution storage unit 32 at 124 ° C. , CO ₂ absorbing solution thermal degradation is reduced by about 40%.

As described above, the CO ₂ recovery device 1002 includes the cooling water supply passage 108 and the cooling water / lean heat exchanger 41c. As a result, the lean solution FL_l in the regeneration space 30a is once extracted out of the regeneration device 30, and after the heat is exchanged with the cooling water CW to lower the temperature, the operation returns to the storage space 30b again. The lean solution FL_l having a temperature lower than that of the lean solution FL_l in the space 30a can be stored in the lean solution storage unit 32, and an effect of suppressing thermal deterioration of the lean solution FL_l is exhibited.

  Note that the cooling water supply passage 108 and the cooling water / lean heat exchanger 41c are not limited to one, and a plurality of cooling water / lean heat exchangers 41c may be installed. Further, the low-temperature medium that exchanges heat with the lean solution FL_l in the lean solution reflux passage 104 is not limited to the cooling water CW, and may be tap water or factory waste water as long as the temperature is lower than the lean solution FL_l. good.

FIG. 6 is a schematic view of a CO ₂ recovery apparatus according to Embodiment 4 of the present invention. FIG. 7 is a diagram showing the relationship between the pressure in the regenerator and the temperature of the lean solution. The CO ₂ recovery device 1003 will be described with reference to FIG. Note that the members that overlap the structure of the CO ₂ recovery unit according to the first embodiment, description thereof will be omitted given the same reference numerals.

The CO ₂ recovery device 1003 includes a pressure control device 60 that adjusts the pressure in the regeneration device 30_2. The pressure control device 60 is a device that includes, for example, a pressurizing pump and a pressure adjusting valve, and can adjust the pressure in the regenerator 30_2. Note that the CO ₂ recovery apparatuses according to the first to third embodiments are provided with partitioning means for partitioning the regeneration apparatus into two spaces, ie, a regeneration space and a storage space, by providing a partition member in the regeneration apparatus. However, the CO ₂ recovery device 1003 does not include the partition member in the regenerator 30_2.

Here, according to the relationship diagram shown in FIG. 7, in Examples 1 to 3, the temperature of the lean solution FL_l before heat exchange with the low-temperature medium is around 124 ° C. It can be seen that the pressure is about 2.0 ata. Therefore, by reducing the pressure in the regenerator 30_2 to less than 2.0ata, the boiling point of the liquid containing water is lowered, and the vapor heat of the lean solution FL_l generated at a lower temperature is converted into the lean solution regenerating heating reflux passage 103. It can be supplied into the playback device 30_2 from the return port 103B. That is, in the decompressed regenerator 30_2, CO ₂ can be removed from the rich solution FL_r at a lower temperature than before.

For example, by setting the pressure in the regenerator 30_2 to 1.5 ata, the lean solution FL_l from which CO _{2 has been} removed in the regenerator 30_2 is stored in the lean solution storage unit 32 at a temperature around 115 ° C.

According to the simulation result shown in FIG. 3, in this embodiment, for example, the lean solution FL_l cooled to 115 ° C. is stored in the lean solution storage unit 32, and compared with the case where it is stored in the lean solution storage unit 32 at 124 ° C. , CO ₂ absorbing solution thermal degradation is reduced by about 25%.

As described above, the CO ₂ recovery device 1003 of the present embodiment includes the pressure control device 60 in the regeneration device 30_2. Thereby, the pressure in the regenerator 30_2 can be reduced, and the rich solution FL_r can be regenerated to the lean solution FL_l at a lower temperature, and the effect of suppressing the thermal deterioration of the lean solution FL_l is exhibited.

As described above, the CO ₂ recovery device and the CO ₂ absorbent regenerator according to the present invention are suitable for use while suppressing thermal deterioration of the CO ₂ absorbent that is circulated and reused in the CO ₂ recovery device. ing.

1000, 1001, 1002, 1003 CO ₂ recovery device 10 Cooling device 20 Absorption device 21 CO ₂ absorption unit 22 Rich solution storage unit 30, 30_1, 30_2 Regeneration device 30a, 30_1a Regeneration space 30b, 30_1b Storage space 31 Recovery unit 32 Lean solution Reservoir 33 Chimney tray 34 Partition member 40 Second rich / lean heat exchanger 41 First rich / lean heat exchanger 41a First semi-lean / lean heat exchanger 41b Second semi-lean / lean heat exchanger 41c Cooling water / lean heat Exchanger 50 Regenerative heater 60 Pressure control device 100 Exhaust gas supply passage 101 Rich solution supply passage 102 Lean solution supply passage 103 Lean solution regeneration heating reflux passage 104 Lean solution reflux passage 105 First semi-lean solution reflux passage 106 Second semi-lean solution reflux Road 108 cooling water supply passage

Claims (9)

An absorption device for removing CO ₂ in the gas contacting the gas and the CO ₂ absorbing liquid containing CO _2, CO ₂ rich solution the a CO ₂ absorbent having absorbed CO ₂ absorption device a reproducing apparatus for reproducing to remove, and the rich solution supply passage for supplying the rich solution to the reproducing apparatus from the absorber, is CO ₂ absorbing solution from which CO ₂ has been removed to the absorber from the playback device A lean solution supply passage for supplying a lean solution; a partitioning means for partitioning the regeneration device into a regeneration space for removing CO ₂ in the rich solution and a storage space for temporarily storing the lean solution; and the regeneration The lean solution reflux passage for extracting the lean solution in the space and returning it to the storage space, and the heat exchange between the lean solution passing through the lean solution reflux passage and a medium having a temperature lower than that of the lean solution. CO ₂ recovery apparatus characterized by having a means for. The means for exchanging heat with the medium having a temperature lower than that of the lean solution is a first rich / lean heat exchanger for exchanging heat between the lean solution and the rich solution passing through the rich solution supply passage. The CO ₂ recovery device according to claim 1. Means for exchanging heat with a medium having a temperature lower than that of the lean solution is a semi-lean / lean heat exchanger for exchanging heat between the lean solution and a semi-lean solution from which CO ₂ has been partially removed in the regeneration space. The CO ₂ recovery device according to claim 1. The rich solution supply passage is configured to exchange heat between the rich solution and the lean solution passing through the lean solution supply passage between the absorber and the first rich / lean heat exchanger. The CO ₂ recovery device according to claim 2, further comprising a heat exchanger. The CO ₂ recovery apparatus according to claim 1, wherein the medium having a temperature lower than that of the lean solution is cooling water. The CO ₂ recovery apparatus according to claim 1, further comprising a pressure control device that adjusts the pressure in the regenerator. Removing the CO ₂ rich solution is CO ₂ absorbent having absorbed CO _2, the inside reproducing apparatus CO ₂ plays a lean solution which is the CO ₂ absorbing liquid that has been removed, CO of the rich solution a dividing means for reproducing space and rie down reservoir for removing ₂ is divided into the storage space provided, and the lean solution return passage for returning to the storage space the lean solution by extracting the reproduction space, the lean solution A CO ₂ absorbent regenerating apparatus, comprising: a means for exchanging heat between the lean solution passing through the reflux passage and a medium having a temperature lower than that of the lean solution. Means for exchanging heat with a medium having a temperature lower than that of the lean solution is a semi-lean / lean heat exchanger for exchanging heat between the lean solution and a semi-lean solution from which CO ₂ has been partially removed in the regeneration space. The CO ₂ absorbent regenerator according to claim 7. The CO ₂ absorbent regenerating apparatus according to claim 7, wherein the medium having a temperature lower than that of the lean solution is cooling water.

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