JP2019000795A - Gas processing apparatus, carbon dioxide recovery apparatus and carbon dioxide recovery method - Google Patents

Abstract

To provide a gas processing apparatus and a carbon dioxide recovery apparatus capable of sufficiently reducing mist accompanied with a washed gas.SOLUTION: A gas processing apparatus 90 includes: an absorption unit 20 bringing an absorbent absorbing carbon dioxide into contact with a raw material gas containing carbon dioxide and forming a processed gas reduced with carbon dioxide than in the raw material gas; and a washing unit 10 having packed layers 10a, 10b passed with the processed gas from the lower side to the upper side. The washing unit 10 has a first demister layer 11 and a second demister layer 12 having a specific surface area smaller than that of the first demister layer 11 in this order from the upper side at a part above the packed layers 10a, 10b.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a gas processing apparatus, a carbon dioxide recovery facility, and a carbon dioxide recovery method.

  A chemical absorption method is known as a method for recovering carbon dioxide from a mixed gas containing carbon dioxide such as blast furnace gas, boiler exhaust gas, natural gas, and petroleum cracked gas. In the chemical absorption method, an absorption liquid and a mixed gas are brought into contact with each other in an absorption tower, and carbon dioxide is absorbed into the absorption liquid to obtain a recovered liquid. The recovered liquid that has absorbed the carbon dioxide is heated in a regeneration tower to release the carbon dioxide, thereby separating the carbon dioxide from the absorbing liquid. The absorbent regenerated in this way is recycled.

  As the absorbing solution, it is known to use amine compounds such as MEA, IPAE, and TMDAH. In patent document 1, the technique which collect | recovers the amine compound which accompanies decarbonation waste gas by making gas-liquid contact with the decarbonation waste gas washing water from which the absorption liquid and the carbon dioxide were absorbed in the water washing part of an absorption tower is proposed. Has been. It has also been proposed to provide a demister at the top of the absorption tower to remove the washing water mist accompanying the decarbonation exhaust gas.

JP 2002-126439 A

  However, in the conventional absorption tower, the mist is not sufficiently removed, and there is a concern that the mist may affect the downstream apparatus. Therefore, an object of the present invention, in one aspect, is to provide a gas processing apparatus and a carbon dioxide recovery facility that can sufficiently reduce mist accompanying the cleaning gas. Another object of the present invention is to provide a carbon dioxide recovery method capable of sufficiently reducing mist accompanying the cleaning gas.

  In one aspect, the present invention provides an absorber that generates a processing gas in which carbon dioxide is reduced compared to the raw material gas by contacting an absorbing liquid that absorbs carbon dioxide with a raw material gas containing carbon dioxide, A gas processing apparatus comprising: a cleaning unit having at least one packed layer through which gas passes upward from below, wherein the cleaning unit is above the packed layer and from above, the first demister layer; Provided is a gas processing apparatus comprising a second demister layer having a specific surface area smaller than that of a first demister layer in this order.

  In order to improve the amount of mist trapped in the process gas, it is considered effective to increase the specific surface area of the demister to reduce the gap (space) in the demister. However, when the specific surface area of the demister is simply increased, there is a concern that the mist, foreign matter, and the like are likely to close due to the gap (space ratio) of the demister being reduced.

  Therefore, the gas processing apparatus includes, from above, a first demister layer and a second demister layer having a specific surface area smaller than that of the first demister layer in this order. In this cleaning section, the first demister layer and the second demister layer are provided above the filling layer, so that it is possible to reduce mist and foreign matters that reach these demister layers.

  And in the 2nd demister layer which has the relatively small specific surface area (large space rate) provided below the 1st demister layer, a big mist, a foreign substance, etc. can be collected. Since such a second demister layer has a larger space ratio than the first demister layer, it is possible to suppress blockage due to mist and foreign matter. Further, since the first demister layer having a relatively large specific surface area (small space ratio) is provided on the upper side of the second demister layer, a small mist that cannot be collected by the second demister layer is provided. It can be collected in one demister layer. Therefore, the mist accompanying the cleaning gas flowing out from the upper part of the cleaning unit can be sufficiently reduced.

  In some embodiments, the cleaning unit may include a tray that collects the cleaning liquid collected by the first demister layer between the first demister layer and the second demister layer. By providing such a tray, the amount of the cleaning liquid collected by the first demister layer flowing down to the second demister layer is reduced. Accordingly, it is possible to suppress the second demister layer from being saturated with the mist and the mist from being scattered again from the second demister layer. Therefore, the collection efficiency can be further improved.

  The tray may include a plurality of openings and a weir that suppresses the fall of the recovered cleaning liquid. Thereby, the flow amount of the cleaning liquid collected by the first demister layer to the second demister layer can be further reduced while suppressing the drift of the gas flow passing through the tray.

  In another some embodiment, you may provide the recirculation | reflux part which recirculates the washing | cleaning liquid collect | recovered with the said tray. The absorption liquid component contained in the cleaning gas flowing out from the upper part of the cleaning part can be sufficiently reduced by the refluxing by the reflux part.

  In another aspect, the present invention provides a gas processing apparatus according to any one of the above-described gas separation and recovery by separating carbon dioxide from a recovery liquid obtained by absorbing carbon dioxide into an absorption liquid in an absorption section of the gas processing apparatus. A carbon dioxide recovery facility comprising: a regenerator that regenerates an absorbing liquid from a liquid.

  Such a carbon dioxide recovery facility can sufficiently reduce the mist accompanying the cleaning gas by including the above-described gas processing apparatus.

  In yet another aspect, the present invention provides a carbon dioxide recovery method using the above-described carbon dioxide recovery facility, wherein an absorption liquid that absorbs carbon dioxide and a raw material gas containing carbon dioxide are brought into contact with each other, and the raw material gas An absorption process that generates a processing gas with reduced carbon dioxide than the above, and a regeneration that separates carbon dioxide from the recovery liquid obtained by absorbing carbon dioxide in the absorption liquid in the absorption process and regenerates the absorption liquid from the recovery liquid And a cleaning step of cleaning the processing gas and collecting mist contained in the processing gas in the first demister layer and the second demister layer to obtain a cleaning gas. A method for recovering carbon dioxide is provided.

  In the carbon dioxide recovery method described above, mist is collected in the first demister layer and the second demister layer in the cleaning step, so that the mist accompanying the cleaning gas can be sufficiently reduced.

  In one aspect, the present invention can provide a gas processing apparatus and a carbon dioxide recovery facility capable of sufficiently reducing mist accompanying the cleaning gas. In another aspect, the present invention can provide a carbon dioxide recovery method capable of sufficiently reducing the mist accompanying the cleaning gas.

FIG. 1 is a diagram schematically illustrating an embodiment of a carbon dioxide recovery apparatus. FIG. 2 is a schematic diagram showing an upper portion of the cleaning unit in the gas processing apparatus of FIG. 1. FIG. 3 is a top view of a tray provided in a cleaning unit in the gas processing apparatus of FIG. 1. FIG. 4 is a schematic view showing an upper part of a cleaning unit in a gas processing apparatus according to another embodiment.

  In some embodiments, a gas processing apparatus is configured to bring a raw material gas containing carbon dioxide into contact with an absorption liquid to generate a processing gas in which carbon dioxide is reduced compared to the raw material gas, and a processing gas And a cleaning section having at least one packed bed that passes from below to above. The cleaning unit includes, in this order, a first demister layer and a second demister layer having a specific surface area smaller than that of the first demister layer above the filling layer and from above.

  The processing gas introduced from the lower part of the cleaning part is cleaned while passing through the packed bed from the bottom to the top. Here, the term “cleaning” refers to reducing the gaseous or mist-like absorption liquid component from the processing gas in the cleaning unit, and the cleaning is, for example, passing through a packed bed or a demister layer and, if necessary, the cleaning unit. By contacting with the cleaning liquid supplied to The cleaning gas obtained by cleaning the processing gas flows out from above the first demister layer of the cleaning unit.

  The first demister layer and the second demister layer may be combined and integrated, or may be arranged apart from each other in the vertical direction. The cleaning unit may include a demister layer other than the first demister layer and the second demister layer. For example, a third demister layer having the same specific surface area as the first demister layer or the second demister layer may be provided between the first demister layer and the second demister layer. The specific surface area of the third demister layer may be between the specific surface area of the first demister layer and the specific surface area of the second demister layer. Further, the cleaning unit has the demister layer only at the upper portion, that is, only above the filling layer, and does not have to have the demister layer below the filling layer from the viewpoint of simplifying the apparatus configuration. The specific surface area in the present disclosure refers to the surface area per unit volume.

  The raw material gas containing carbon dioxide to be processed in the absorption unit may be a gas containing carbon dioxide. Examples of such gas include blast furnace gas, boiler exhaust gas, natural gas, petroleum cracked gas, and exhaust gas generated in various plants. The absorbing liquid may be any liquid that absorbs carbon dioxide, and examples thereof include an aqueous amino solution. Examples of the aqueous amino solution include aqueous solutions such as MEA (monoethanolamine), EAE (ethylaminoethanol), IPAE (isopropaminoethanol), and TMDAH (tetramethyldiaminohexane).

  In some embodiments, the carbon dioxide recovery facility is configured to separate carbon dioxide from the recovery liquid by separating the carbon dioxide from the gas processing apparatus described above and the recovery liquid obtained by absorbing the carbon dioxide into the absorption liquid in the absorption section. A regenerating apparatus for regenerating the absorbing liquid. The carbon dioxide recovery facility may include a purifier for increasing the purity of carbon dioxide on the downstream side of the regenerator. Thereby, high purity carbon dioxide can be produced. However, it is not always essential to produce high-purity carbon dioxide, and it is not particularly limited as long as it is a facility that can recover a gas having a higher concentration of carbon dioxide than the source gas.

  The gas processing apparatus and the carbon dioxide recovery facility described above can reduce mist accompanying the cleaning gas. Mist may contain an absorption liquid component in addition to moisture. Therefore, the environmental load can be reduced by reducing the outflow of mist to the outside of the gas processing apparatus and the carbon dioxide recovery facility.

  An embodiment of a gas processing apparatus and carbon dioxide recovery equipment including the same will be described with reference to the drawings. However, the following embodiment is an illustration and an absorber is not limited to the following content. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted in some cases. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  FIG. 1 is a diagram schematically illustrating a gas processing apparatus 90 and a carbon dioxide recovery facility 100 including the gas processing apparatus 90 according to the present embodiment. The carbon dioxide recovery facility 100 is an apparatus that recovers carbon dioxide from a raw material gas by a chemical absorption method, and includes a gas processing device 90 having a cleaning unit 10 and an absorption unit 20, a regeneration unit 30 (regeneration device), a purification unit, and the like. Unit 40 (purification device). In addition, the flow path in this specification may be comprised, for example with piping, and may be comprised with the tank and the tank in addition to piping.

  The raw material gas containing carbon dioxide is introduced into the lower part of the absorption part 20 composed of an absorption tower. Connected to the upper part of the absorption unit 20 is a flow path 36 c for supplying the absorption liquid regenerated by the regeneration unit 30 into the absorption unit 20. In the absorption unit 20, the raw material gas and the absorption liquid that absorbs carbon dioxide are in countercurrent contact.

  In the absorption unit 20, carbon dioxide contained in the raw material gas is absorbed by the absorption liquid. The amount of carbon dioxide absorbed by the absorbent depends on the temperature. For this reason, the amount of carbon dioxide absorbed by the absorbing liquid can be adjusted by adjusting the temperature in the absorbing section 20. The absorber 20 may have a packed bed in order to improve the contact efficiency between the source gas and the absorbing liquid. The filling layer is filled with a filling such as Raschig ring, for example. A tray (not shown) may be installed between the plurality of packed beds.

  In the absorption unit 20, the absorption liquid descends while being in gas-liquid contact with the raw material gas, absorbs carbon dioxide contained in the raw material gas, and becomes a recovered liquid. The recovered liquid contains carbon dioxide and an absorbing liquid, and has a higher carbon dioxide concentration than the absorbing liquid. The temperature in the absorption part 20 can be set, for example according to the kind of absorption liquid, for example, is 30-40 degreeC. The pressure in the absorber 20 is, for example, 0 to 1.0 MPa. The recovered liquid is stored at the bottom of the absorption unit 20 and flows out of the absorption unit 20 through the flow path 24a connected to the bottom.

  The processing gas obtained by removing at least a part of carbon dioxide from the raw material gas in the absorption unit 20 flows out from the absorption unit 20 through the flow path 22 connected to the tower top of the absorption unit 20. The processing gas flows through the flow path 22 and is introduced into the lower part of the cleaning unit 10 constituted by a cleaning tower. On the other hand, a cleaning liquid (for example, water) for cleaning the processing gas is introduced into the upper portion of the cleaning unit 10 through the flow path 18. The processing gas introduced into the cleaning unit 10 comes into contact with the cleaning liquid descending in the cleaning unit 10 while moving in the cleaning unit 10 from below to above. As a result, the processing gas is cleaned and the absorption liquid component contained in the processing gas is reduced.

  The cleaning unit 10 includes filling layers 10a and 10b. The filling layers 10a and 10b are filled with a filler such as Raschig rings, for example. The cleaning unit 10 includes a tray 10c between the packed layers 10a and 10b. The tray 10c has a structure in which the cleaning liquid containing the absorption liquid component can stay. The cleaning liquid staying in the tray 17 is refluxed by the first reflux unit 71 including the flow path, the pump, and the cooler, and returns to the cleaning unit 10 above the tray 10c.

  The cleaning liquid that has returned to the cleaning unit 10 flows down in the cleaning unit 10 and reduces mist-like or gaseous absorption liquid components contained in the processing gas. Thus, the cleaning unit 10 can improve the contact efficiency between the processing gas and the cleaning liquid by including the packed layers 10a and 10b, the tray 10c, and the first reflux unit 71. The structure of the tray 17 is not particularly limited, and may be a chimney tray, for example.

  The processing gas containing mist passes through the packed layer 10b, the tray 10c, and the packed layer 10a in this order while rising in the cleaning unit 10, and reaches the second demister layer 12. For this reason, the content of the absorption liquid component in the processing gas at the time of reaching the second demister layer 12 is lower than the content of the absorption liquid component of the processing gas at the time of introduction into the cleaning unit 10. . However, various mists having different sizes remain in the processing gas when it reaches the second demister layer 12. These mists contain an absorbent component.

  Since the second demister layer 12 has a smaller specific surface area and a larger space ratio than the first demister layer 11, even if mist having a large size is collected, it is not easily clogged. Moreover, even if the solid substance contained in source gas and the foreign material produced by corrosion etc. in the washing | cleaning part 10 are captured, it will not block easily. For this reason, the washing | cleaning part 10 provided with the 2nd demister layer 12 can perform the cleaning of process gas stably continuously.

  On the other hand, the first demister layer 11 provided on the upper side of the second demister layer 12 has a specific surface area larger than that of the second demister layer 12 and has a small space ratio, so that it cannot be collected by the second demister layer 12. It is possible to collect mist having For this reason, the mist contained in the processing gas can be sufficiently reduced by passing through the first demister layer 11.

  The processing gas in which the mist is sufficiently reduced flows out from the cleaning unit 10 as the cleaning gas through the flow path 13 connected to the top of the cleaning unit 10. Since the mist is sufficiently reduced by the first demister layer 11 and the second demister layer 12, the cleaning gas that flows out may be discharged to the atmosphere after flowing through the flow path 13. Further, it may be introduced into an apparatus provided on the downstream side of the cleaning unit 10 according to the components of the cleaning gas.

As the first demister layer 11 and the second demister layer 12, a normal mesh type can be used. The specific surface area of the first demister layer 11 is, for example, 700 to 3000 m ² / m ³ , and preferably 1000 to 2000 m ² / m ³ . The specific surface area of the second demister layer 12 is, for example, 100~1500m ² / ^{m 3,} preferably 200~1000m ² / ^{m 3.} The space ratio of the first demister layer 11 may be, for example, 85 to 97%. The space ratio of the second demister layer 12 may be 97 to 99%, for example. The space ratio here is the ratio of the space to the volume of each demister layer.

  FIG. 2 is a cross-sectional view schematically showing an upper portion of the cleaning unit 10 in the carbon dioxide recovery facility of FIG. The cleaning unit 10 includes a tray 17 configured to allow the cleaning liquid 50 to stay between the first demister layer 11 and the second demister layer 12. The tray 17 having a substantially disk-shaped outer shape has an opening 17a through which the processing gas and the cleaning liquid flow, and a cylindrical weir 17b provided so as to surround the opening 17a. The cleaning liquid 50 collected by the first demister layer 11 flows down to the tray 17, and at least a part of the cleaning liquid stays on the tray 17 by the weir 17b. The cleaning liquid 50 staying on the tray 17 flows out to the flow path 19 constituting the second reflux unit 72. The cleaning liquid 50 contains, for example, moisture and an absorbing liquid.

  As shown in FIG. 1, at least a part of the cleaning liquid 50 that has flowed out into the flow path 19 flows through the flow path 19, the flow path 14, the pump 74, and the flow path 16, and the central portion of the cleaning section 10 (filled layer 10a). , 10b). Thus, the flow path 19, the flow path 14, the pump 74, and the flow path 16 constitute the second reflux unit 72. Thus, the cleaning liquid 50 collected in the tray 17 is returned to the cleaning unit 10 by the second reflux unit 72. The cleaning liquid 50 that has returned to the cleaning unit 10 comes into countercurrent contact with the mist-like or gaseous absorption liquid component rising in the cleaning unit 10 and takes in at least a part of the absorption liquid component. Therefore, scattering of the absorption liquid component is suppressed by the recirculation by the second recirculation part 72, and the absorption liquid component contained in the cleaning gas flowing out from the cleaning part 10 can be reduced.

  FIG. 3 is a top view of the tray 17. The tray 17 preferably has a plurality of openings 17a from the viewpoint of suppressing the drift of the processing gas and improving gas-liquid contact. When the tray 17 is viewed from above as shown in FIG. 3, the ratio of the total area of the plurality of openings 17a to the entire area of the tray 17 is preferably 40 to 80%, and preferably 50 to 70%. More preferred. With such a ratio, the pressure loss can be sufficiently reduced while maintaining the recovered amount of the cleaning liquid 50.

  The temperature in the washing | cleaning part 10 may change according to the temperature in the absorption part 20, for example, is 20-40 degreeC, for example. The pressure in the cleaning unit 10 is, for example, 0 to 1.0 MPa. The structure of the tray provided in the washing | cleaning part 10 is not specifically limited, For example, a normal chimney tray may be sufficient and it may not have a weir like a sheave tray.

  Returning to FIG. 1, a cleaning liquid such as water is introduced into the cleaning unit 10 through a flow path 18 connected to the cleaning unit 10 below the second demister layer 12. The cleaning liquid takes in the mist-like or gaseous absorption liquid component while dropping in the cleaning unit 10. The cleaning water that has taken in the absorbent component is stored at the bottom of the cleaning unit 10. This cleaning water flows out of the cleaning unit 10 through the flow channel 14 connected to the bottom of the cleaning unit 10 and merges with the cleaning liquid flowing through the flow channel 19. A part of the combined cleaning liquid flows through the pump 74, the flow path 14 and the flow path 16 and returns to the cleaning unit 10 as described above, and the other part of the combined cleaning liquid is the pump 74, the flow path 14 and the flow path. 15 is circulated to join the recovered liquid flowing through the flow path 24a.

  The recovered liquid flowing out from the absorption unit 20 to the flow path 24 a joins with the cleaning liquid flowing through the flow path 15 and then introduced into the heat exchanger 65. Here, heat is exchanged with the absorbing liquid (lean liquid) flowing out from the regenerating unit 30 through the flow path 36a, and is heated to, for example, 80 to 90 ° C. The absorption liquid heated by the heat exchanger 65 is introduced into the regeneration unit 30 configured by a regeneration tower through the flow path 24b. The flow path 24 b is connected to the upper part of the reproducing unit 30.

  The regeneration unit 30 separates carbon dioxide from the recovered liquid (rich liquid) obtained by the absorption liquid absorbing carbon dioxide in the absorption unit 20 to regenerate the absorption liquid (lean liquid). The regeneration unit 30 may include a packed bed in order to efficiently separate the liquid and the gas. The packed layer is filled with a filler such as a Raschig ring, for example.

  The recovered liquid introduced into the regeneration unit 30 flows down in the regeneration unit 30 and stays on a tray provided at or near the bottom of the regeneration unit 30. The regenerator 30 is provided with a heater 31 that heats the recovered liquid (absorbed liquid) staying at or near the bottom of the regenerator 30. The recovered liquid flows through the flow path 34a and is introduced into the heater 31, and is heated by exchanging heat with water vapor as a heat medium. The absorption liquid is heated to, for example, 80 to 130 ° C. by the heater 31. The recovered liquid heated by the heater 31 flows through the flow path 34b or the flow path 34c and returns to the regeneration unit 30.

  The heater 31 is a heat exchanger, and heats the recovered liquid by performing heat exchange with water vapor that is a heat medium. The water vapor flows through the flow path 33 and is supplied to the heater 31. The gas containing carbon dioxide separated from the recovered liquid rises in the regeneration unit 30. The gas flows out of the regeneration unit 30 as a separation gas through a flow path 32 a connected to the top of the regeneration unit 30. In this way, carbon dioxide contained in the raw material gas is separated from the recovered liquid, and the absorbing liquid is regenerated. The concentration of carbon dioxide in the separation gas flowing out from the flow path 32a is, for example, 99% by volume or more, and preferably 99.9% by volume or more.

  Connected to the bottom of the regenerating unit 30 is a flow path 36 a for discharging an absorbing liquid (lean liquid) with reduced carbon dioxide from the regenerating unit 30. The absorption liquid flows through the flow path 36 a and is introduced into the heat exchanger 65, and is cooled by heat exchange with the recovery liquid from the absorption unit 20. Thereafter, the absorbing liquid cooled by the heat exchanger 65 is introduced into a cooler (not shown), and cooled to, for example, 30 to 40 ° C. Thereafter, the absorption liquid flows through the flow path 36 c and is introduced into the upper portion of the absorption unit 20. As described above, the absorption liquid (recovered liquid) is used while circulating through the cleaning unit 10, the absorption unit 20, and the regeneration unit 30.

  The separation gas is discharged from the top of the regeneration unit 30, flows through the flow path 32 a, and is introduced into the cooler 35. The process gas is cooled by heat exchange with the cooling water CW in the cooler 35. A part of the processing gas may be condensed by the cooling in the cooler 35. The condensate produced here is circulated through the flow path 32b by the pump and is returned to the regeneration unit 30.

  The remaining portion of the separation gas cooled by the cooler 35 flows through the flow path 32c and is introduced into the compressor 60. The pressure is raised to 0.8 to 1 MPa and the temperature is raised to 100 to 150 ° C. In the cooler 62 provided on the downstream side of the compressor 60, the processing gas whose pressure has been increased and raised by the compressor 60 is cooled to, for example, 30 to 50 ° C. by heat exchange with the cooling water CW introduced into the cooler 62. Is done.

  The processing gas cooled by the cooler 62 is heated to, for example, 130 to 150 ° C. in the heat exchanger 63 by exchanging heat with the carbon dioxide gas obtained in the impurity removal tower 42 in the purification unit 40. The separated gas heated by the heat exchanger 63 is heated to a temperature (for example, 150 to 170 ° C.) suitable for processing in the impurity removal tower 42 by exchanging heat with water vapor in the heat exchanger 64. The heat medium used in the heat exchanger 64 may be water vapor or heat medium oil.

The separation gas heated by the heat exchanger 64 is introduced into the impurity removal tower 42. In the impurity removal tower 42, impurities contained in the separation gas are removed. Examples of impurities include oxides such as NO _x and oxygen. Examples of the impurity removal tower 42 include a catalyst tower in which a reduction catalyst is accommodated and an adsorption tower in which an adsorbent such as activated carbon is accommodated.

  When the impurity removal tower 42 is a catalyst tower, the separation gas is brought into contact with the reduction catalyst in a hydrogen atmosphere, whereby impurities contained in the separation gas are reduced and the purity of carbon dioxide is improved. As the reduction catalyst used in the catalyst tower, a known deoxygenation catalyst can be used. For example, a catalyst in which a noble metal is supported on a carrier can be mentioned. Examples of the carrier include aluminum oxide and magnesium oxide. Examples of noble metals include platinum, palladium, rhodium, ruthenium and alloys thereof. The carrier and the noble metal may be used alone or in combination of two or more.

  On the other hand, when the impurity removal tower 42 is an adsorption tower, the separation gas comes into contact with the adsorbent, thereby reducing impurities contained in the separation gas and improving the purity of carbon dioxide. The purification unit 40 may include either one of the catalyst tower and the adsorption tower, or a combination of both.

  In the impurity removal tower 42, impurities are removed from the separation gas, and carbon dioxide gas is obtained. The purity of the carbon dioxide gas is, for example, 99.9% by volume or more. The “carbon dioxide gas” in the present disclosure only needs to be higher in purity of carbon dioxide than the separated gas, and may contain impurities. The “volume%” in the present disclosure is a volume ratio in a standard state (25 ° C., 1 bar).

  The carbon dioxide gas obtained in the impurity removal tower 42 flows through the flow path 42 a and is introduced into the heat exchanger 63 at a temperature of 150 to 170 ° C. The carbon dioxide gas is cooled to, for example, 130 to 150 ° C. by exchanging heat with the separation gas in the heat exchanger 63. The carbon dioxide gas cooled by the heat exchanger 63 is introduced into the cooler 45. The carbon dioxide gas is cooled to, for example, 20 to 40 ° C. through heat exchange with the cooling water CW in the cooler 45.

  The carbon dioxide gas cooled in the cooler 45 is introduced into the dehumidifier 44. The dehumidifier 44 contains an adsorbent such as zeolite. In the dehumidifier 44, carbon dioxide gas comes into contact with the adsorbent, and moisture contained in the carbon dioxide gas is reduced. By adjusting the temperature or pressure of the dehumidifier, the water once adsorbed by the adsorbent is desorbed from the adsorbent. Thereby, water contained in carbon dioxide gas can be separated.

  The carbon dioxide gas dehumidified by the dehumidifier 44 is introduced into the deodorization tower 46 after moisture and the like are reduced in the dehumidifier 44. The deodorizing tower 46 contains activated carbon. In the deodorization tower 46, carbon dioxide gas contacts activated carbon, and the odor component contained in carbon dioxide gas is reduced. Examples of the odor component include hydrogen sulfide generated in the impurity removal tower 42 and hydrocarbon.

The carbon dioxide gas deodorized by the deodorization tower 46 is transferred to a tank or the like and stored. The carbon dioxide gas (CO ₂ ) thus obtained has a sufficiently reduced impurity concentration, and its purity is, for example, 99.95% by volume or more. Such high-purity carbon dioxide gas can be suitably used for beverage or food applications, for example.

  The gas processing apparatus 90 and the carbon dioxide recovery facility 100 including the gas processing apparatus 90 can sufficiently reduce the mist accompanying the cleaning gas discharged from the cleaning unit 10 and the absorbent component included in the cleaning gas. it can. Therefore, the load on the apparatus on the downstream side of the cleaning unit 10 and the environmental load can be reduced. Moreover, dissipation of an absorbent is suppressed and the absorbent can be saved.

  As mentioned above, although one Embodiment of the gas processing apparatus 90 and the carbon dioxide recovery equipment 100 was described, the structure of each apparatus and each part is not limited to the above-mentioned embodiment. For example, according to the purity of the required carbon dioxide gas, the structure of the refinement | purification part 40 may be changed suitably, and the refinement | purification part 40 does not need to be provided. Moreover, you may comprise the washing | cleaning part 10 and the absorption part 20 with one tower, without comprising each with an independent tower. In this case, a washing part may be provided on the upper side of the tower and an absorption part on the lower side. Thus, the mist accompanying the cleaning gas flowing out from the upper portion of the tower can be reduced also by the gas processing apparatus having both the cleaning section and the absorption section in one tower.

  The gas processing apparatus 90 and the carbon dioxide recovery facility 100 may have any appropriate apparatus depending on the properties of the source gas. For example, when the source gas contains a sulfur compound, a desulfurization unit may be provided on the upstream side of the absorption unit 20. In the desulfurization section, the raw material gas and the alkaline aqueous solution are brought into gas-liquid contact to absorb sulfur oxide and the like in the alkaline aqueous solution. Examples of the alkaline aqueous solution include a calcium carbonate aqueous solution, a sodium hydroxide aqueous solution, a magnesium hydroxide aqueous solution, and aqueous ammonia.

  FIG. 4 is a schematic cross-sectional view showing an upper portion of a cleaning unit 10A in a gas processing apparatus according to another embodiment. 10 A of washing | cleaning parts are equipped with the 1st demister layer 11 and the 2nd demister layer 12 on the upper part from the upper side. The first demister layer 11 and the second demister layer are provided in contact with each other. The first demister layer 11 and the second demister layer may be integrated. That is, one demister may be divided into two layers. Even in the gas processing apparatus including the cleaning unit 10A as shown in FIG. 4, the mist accompanying the cleaning gas can be sufficiently reduced. The configuration of the gas processing apparatus and the carbon dioxide recovery equipment other than the cleaning unit 10A is the same as that of the gas processing apparatus 90 and the carbon dioxide recovery equipment 100 shown in FIG.

  Next, a carbon dioxide recovery method using a carbon dioxide recovery facility will be described. Some embodiments of this recovery method can be performed using carbon dioxide recovery equipment 100. This recovery method includes an absorption process, a regeneration process, and a cleaning process. Each of these steps may be performed concurrently.

  In the absorption step, in the absorption unit 20, an absorption liquid that absorbs carbon dioxide and a raw material gas containing carbon dioxide are brought into contact with each other to generate a processing gas in which carbon dioxide is reduced as compared with the raw material gas. In the regeneration step, the regeneration unit 30 separates carbon dioxide from the recovered liquid obtained in the absorption step, and regenerates the absorbed liquid from the recovered liquid. In the cleaning step, the processing gas is introduced into the cleaning unit 10 to clean the processing gas, and the mist contained in the processing gas is collected in the first demister layer 11 and the second demister layer 12 to obtain the cleaning gas. In the cleaning step, the processing gas may be cleaned using a cleaning liquid containing water. Each process can be performed by appropriately applying the description regarding the carbon dioxide recovery facility 100 described above. For example, in the cleaning step, the processing gas may be cleaned while refluxing by the first reflux unit 71 and the second reflux unit 72.

  In the carbon dioxide recovery method, since mist is collected in the first demister layer 11 and the second demister layer 12 in the cleaning step, mist accompanying the cleaning gas flowing out from the cleaning unit 10 is sufficiently reduced. Can do. Moreover, the absorption liquid component contained in the cleaning gas flowing out from the upper part of the cleaning unit 10 can be sufficiently reduced.

  Although one embodiment of the carbon dioxide recovery method has been described above, the method is not limited to this. For example, when the carbon dioxide recovery facility has a desulfurization section, it may have a desulfurization step in which the raw material gas and the alkaline aqueous solution are brought into gas-liquid contact to absorb sulfur oxides and the like in the alkaline aqueous solution.

  According to the present disclosure, a gas processing apparatus installation and a carbon dioxide recovery facility capable of sufficiently reducing mist accompanying the cleaning gas are provided. In addition, a carbon dioxide recovery method capable of sufficiently reducing the mist accompanying the cleaning gas is provided.

  DESCRIPTION OF SYMBOLS 10,10A ... Cleaning part, 10a, 10b ... Packing layer, 11 ... 1st demister layer, 12 ... 2nd demister layer, 13, 14, 15, 16, 18, 19, 22, 24a, 24b, 32a, 32b, 32c, 33, 34a, 34b, 34c, 36a, 36c, 42a ... flow path, 17 ... tray, 17a ... opening, 17b ... weir, 20 ... absorption unit, 30 ... regeneration unit (regeneration device), 31 ... heater, 35 ... cooler, 40 ... purification section, 42 ... impurity removal tower, 44 ... dehumidifier, 45 ... cooler, 46 ... deodorization tower, 50 ... cleaning solution, 60 ... compressor, 62 ... cooler, 63, 64, 65 ... heat exchanger, 71 ... first reflux section, 72 ... second reflux section, 74 ... pump, 90 ... gas processing device, 100 ... carbon dioxide recovery facility.

Claims (6)

An absorber that absorbs carbon dioxide and a raw material gas containing carbon dioxide are brought into contact with each other to generate a processing gas in which carbon dioxide is reduced from the raw material gas, and the processing gas passes from below to above. A gas processing apparatus comprising: a cleaning unit having at least one packed bed;
The cleaning unit is a gas processing apparatus having a first demister layer and a second demister layer having a specific surface area smaller than that of the first demister layer in this order above the filling layer and from above.   2. The gas processing apparatus according to claim 1, wherein the cleaning unit includes a tray that collects the cleaning liquid collected by the first demister layer between the first demister layer and the second demister layer. The tray
The gas processing apparatus according to claim 2, comprising a plurality of openings and a weir that suppresses the fall of the recovered cleaning liquid.   The gas processing apparatus according to claim 2, further comprising a reflux unit configured to reflux the cleaning liquid collected by the tray to the cleaning unit. The gas processing apparatus according to any one of claims 1 to 4,
A regenerator that separates carbon dioxide from a recovery liquid obtained by absorbing carbon dioxide in the absorption liquid in the absorption unit of the gas processing apparatus and regenerates the absorption liquid from the recovery liquid, Carbon recovery equipment. A carbon dioxide recovery method using the carbon dioxide recovery facility according to claim 5,
An absorption step of contacting the absorption liquid that absorbs carbon dioxide with a raw material gas containing carbon dioxide to generate the processing gas in which carbon dioxide is reduced from the raw material gas;
A regeneration step of separating carbon dioxide from a recovery liquid obtained by absorbing carbon dioxide in the absorption liquid in the absorption step, and regenerating the absorption liquid from the recovery liquid;
A cleaning step of introducing the processing gas into the cleaning unit, cleaning the processing gas, and collecting mist contained in the processing gas in the first demister layer and the second demister layer to obtain a cleaning gas; A method for recovering carbon dioxide.

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