Liquefied carbon dioxide storage tank and liquefied carbon dioxide discharge method

Abstract

A liquefied carbon dioxide storage tank is provided with: a tank main body capable of storing liquefied carbon dioxide; a collection tank integrally provided to the tank main body and having a recess recessed from the bottom of the tank main body; and a heating unit capable of heating the interior of the collection tank.

Description

Technical Field

[0001] The present invention relates to a liquefied carbon dioxide storage tank and a method for discharging liquefied carbon dioxide.

[0002] This application claims priority from Japanese Patent Application No. 2022-128622 filed in Japan on August 12, 2022, and the contents are incorporated herein by reference. Background Art

[0003] For example, the fuel tank disclosed in Patent Document 1 is equipped with a loading pipe (pipeline) for loading liquefied gas (LNG: Liquefied Natural Gas) into the fuel tank and a discharge pipe (pipeline) for discharging the liquefied gas from the fuel tank. A pump for sucking out the liquefied gas in the tank is provided at the lower end of the discharge pipe. In such a structure, the liquefied gas in the tank is sucked out by the pump and discharged to the outside of the tank through the discharge pipe.

[0004] Prior art literature

[0005] Patent Document 1: Japanese Patent Application No. 2018-528119 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, when discharging the liquefied gas in the tank, if a pump provided at the lower end of the discharge pipe is used as in the structure disclosed in Patent Document 1, a portion of the liquefied gas remains below the pump in the tank after the liquefied gas is discharged.

[0008] In the case where liquefied carbon dioxide is contained in a tank, if the liquefied carbon dioxide contains impurities such as water and oil, then after the liquefied carbon dioxide is discharged from the tank, the impurities also remain in the tank together with the liquefied carbon dioxide. Moreover, after the liquefied carbon dioxide is discharged from the tank, the liquefied carbon dioxide remaining in the tank sometimes evaporates, for example, due to a temperature rise or a pressure drop in the tank. As a result, impurities having a higher boiling point than the liquefied carbon dioxide remain intact in the liquefied carbon dioxide. As a result, the concentration of the impurities increases relative to the liquefied carbon dioxide that remains in a liquid state. In the case where the impurities are, for example, substances that may have an adverse effect on the material of the tank, the degree of the adverse effect caused by the impurities becomes higher.

[0009] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a liquefied carbon dioxide storage tank and a liquefied carbon dioxide discharge method capable of suppressing the influence of impurities contained in the liquefied carbon dioxide remaining in the tank body after the liquefied carbon dioxide is discharged from the tank body.

[0010] Means for solving problems

[0011] In order to solve the above-mentioned problems, the liquefied carbon dioxide storage tank disclosed in the present invention comprises: a tank body, a storage tank and a heating unit. The tank body can store liquefied carbon dioxide. The storage tank is integrally provided in the tank body. The storage tank has a recessed portion recessed from the bottom of the tank body. The heating unit can heat the inside of the storage tank.

[0012] The method for discharging liquefied carbon dioxide disclosed in the present invention discharges the liquefied carbon dioxide stored in the tank body from the inside of the liquefied carbon dioxide storage tank as described above. The method for discharging the liquefied carbon dioxide includes the following steps: a step of discharging the liquefied carbon dioxide; and a step of heating the inside of a storage tank. In the step of discharging the liquefied carbon dioxide, the liquefied carbon dioxide stored in the tank body is discharged to the outside of the tank body. In the step of heating the inside of the storage tank, after the liquefied carbon dioxide is discharged to the outside of the tank body, the inside of the storage tank is heated.

[0013] Effects of the Invention

[0014] According to the liquefied carbon dioxide storage tank and the method for discharging liquefied carbon dioxide of the present disclosure, it is possible to suppress the influence of impurities contained in the liquefied carbon dioxide remaining in the tank body after the liquefied carbon dioxide is discharged from the tank body. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a cross-sectional view showing a schematic structure of a liquefied carbon dioxide storage tank according to an embodiment of the present disclosure.

[0016] Figure 2 It is along Figure 1 A longitudinal cross-sectional view taken along line II-II.

[0017] Figure 3 This is a flowchart showing the steps of the method for discharging liquefied carbon dioxide according to the embodiment of the present disclosure.

[0018] Figure 4 It is a cross-sectional view showing a schematic structure of a liquefied carbon dioxide storage tank according to a first modified example of the embodiment of the present disclosure.

[0019] Figure 5 It is a cross-sectional view showing a schematic structure of a liquefied carbon dioxide storage tank according to a second modified example of the embodiment of the present disclosure.

[0020] Figure 6 It is a cross-sectional view showing a schematic structure of a liquefied carbon dioxide storage tank according to another modified example of the embodiment of the present disclosure. DETAILED DESCRIPTION

[0021] Below, refer to Figures 1 to 3A liquefied carbon dioxide storage tank and a method for discharging liquefied carbon dioxide according to an embodiment of the present disclosure will be described.

[0022] (Overall structure of liquefied carbon dioxide storage tank)

[0023] like Figure 1 As shown, a liquefied carbon dioxide storage tank 1A in this embodiment mainly includes a tank body 2, a collecting tank 5A, a discharge pipe 7A, and a heating unit 10A.

[0024] The tank body 2 can store liquefied gas such as liquefied carbon dioxide, etc. The tank body 2 is installed in the hull of a ship, the floating body of an offshore floating equipment, a liquefied gas storage facility on land, etc.

[0025] like Figure 1 , Figure 2 As shown, the tank body 2 is, for example, cylindrical. The liquefied carbon dioxide storage tank 1A comprises a cylindrical portion 3 and an end plate portion 4. The cylindrical portion 3 extends in the central axis direction Dc thereof. In this embodiment, the central axis direction Dc becomes a direction intersecting the up-down direction Dv. The central axis direction Dc may be along the horizontal direction or may be inclined relative to the horizontal direction. In this embodiment, the cylindrical portion 3 is formed into a cylindrical shape, and the cross-sectional shape orthogonal to the central axis direction Dc thereof is circular. The end plate portions 4 are respectively arranged at both ends of the cylindrical portion 3 in the central axis direction Dc. Each end plate portion 4 is hemispherical and closes the opening of the cylindrical portion 3 in the central axis direction Dc.

[0026] In addition, the tank body 2 may be arranged so that the central axis direction Dc is along the vertical direction Dv. In addition, the tank body 2 is not limited to a cylindrical shape, and may be other shapes such as a spherical shape or a square shape.

[0027] The collecting groove 5A is integrally provided in the tank body 2. The collecting groove 5A of the present embodiment is integrally provided at a position including the lower end portion of the cylindrical portion 3 of the tank body 2. The collecting groove 5A is formed to be recessed downward in the up-down direction Dv from the bottom 2b located at the bottom when viewed in a cross section perpendicular to the central axis direction Dc in the inner surface of the tank body 2. The collecting groove 5A of the present embodiment is further arranged at the lowest portion located in the up-down direction Dv in the bottom 2b extending along the central axis direction Dc. For example, when the bottom 2b is bent downward or inclined in the central axis direction Dc, the collecting groove 5A is formed to include the lowest position in the bottom 2b. In addition, the bottom 2b and the collecting groove 5A of the present embodiment are arranged vertically below the top of the tank body 2 because the cylindrical portion 3 is circular in cross section, but the arrangement of the bottom 2b and the collecting groove 5A is not limited to vertically below the top of the tank body 2.

[0028] The collecting tank 5A includes, for example, a peripheral wall portion 5w and a bottom plate portion 5d. The peripheral wall portion 5w is formed into a cylindrical shape extending along the up-down direction Dv. The upper end of the peripheral wall portion 5w is joined to the lower end of the tank body 2, and is open upward from the bottom 2b in the tank body 2. The peripheral wall portion 5w protrudes downward from the tank body 2. The bottom plate portion 5d blocks the opening of the lower end of the peripheral wall portion 5w from below. By means of such a peripheral wall portion 5w and the bottom plate portion 5d, a recessed portion 5h that is recessed downward from the bottom 2b of the tank body 2 is formed. Figure 2 As shown, the collecting tank 5A of this embodiment is located at a symmetrical position ( Figure 2 The peripheral wall portions 5w are disposed facing each other at positions symmetrical to each other in the middle. In addition, the volume of the recessed portion 5h formed by the collecting groove 5A is set according to the size and shape of the tank body 2, etc.

[0029] The discharge pipe 7A is connected to the inside of the tank body 2. In the present embodiment, the discharge pipe 7A penetrates the top of the tank body 2 from the outside of the tank body 2 and extends to the inside of the tank body 2. The front end of the discharge pipe 7A is arranged at the lower part of the tank body 2. A pump 8A is provided at the front end of the discharge pipe 7A. The pump 8A is arranged in the tank body 2. The pump 8A sucks the liquefied carbon dioxide L in the tank body 2 and sends it to the outside of the tank body 2 through the discharge pipe 7A. In this way, the liquefied carbon dioxide L stored in the tank body 2 is discharged to the outside of the tank body 2 through the discharge pipe 7A. Here, after the liquefied carbon dioxide L in the tank body 2 is discharged to the outside of the tank body 2 by the pump 8A and the discharge pipe 7A, the liquefied carbon dioxide L remains in the tank body 2 at a lower position than the pump 8A in the up-down direction Dv. The remaining liquefied carbon dioxide L accumulates in the storage tank 5A.

[0030] The heating unit 10A is capable of heating the inside of the collection tank 5A. The heating unit 10A heats the liquefied carbon dioxide L in the collection tank 5A. The heating unit 10A is provided with a pipe 11A. The pipe 11A penetrates the top of the tank body 2 from the outside of the tank body 2 and extends to the inside of the tank body 2. In the present embodiment, the front end portion 11s of the pipe 11A is arranged inside the collection tank 5A. The base end portion (not shown) of the pipe 11A is connected to a heating fluid supply source (not shown) that supplies the heating fluid. The pipe 11A delivers the heating fluid supplied from the heating fluid supply source from the outside of the tank body 2 to the inside of the collection tank 5A.

[0031] The heating fluid supply source supplies, for example, carbon dioxide gas as the heating fluid. The heating fluid supply source raises the temperature of the heating fluid by heating or pressurizing it. The temperature of the heating fluid supplied from the heating fluid supply source outside the tank body 2 to the storage tank 5A through the piping 11A is higher than the temperature of the liquefied carbon dioxide L in the tank body 2. Moreover, the heating fluid can be set to a temperature higher than the boiling point of the liquefied carbon dioxide L in the tank body 2 and the impurities mixed in the liquefied carbon dioxide L. In addition, the temperature of the heating fluid can be any temperature that can promote the gasification of the liquefied carbon dioxide L and the impurities, and is not limited to a temperature higher than the boiling point of the liquefied carbon dioxide L and the impurities, and can be set to, for example, about -50°C to 80°C.

[0032] Such a heating fluid is sent into the interior of the collecting tank 5A through the pipe 11A, whereby the liquefied carbon dioxide L and impurities mixed in the liquefied carbon dioxide L in the collecting tank 5A are heated.

[0033] (Steps of the method for discharging liquefied carbon dioxide)

[0034] Figure 3 FIG. 1 is a flow chart showing the steps of a method for discharging liquefied carbon dioxide according to an embodiment of the present disclosure. Figure 3 As shown, the method S10 for discharging liquefied carbon dioxide L according to the embodiment of the present disclosure includes: a step S11 of discharging the liquefied carbon dioxide L; and a step S12 of heating the inside of the storage tank 5A.

[0035] In step S11 of discharging liquefied carbon dioxide L, liquefied carbon dioxide L stored in the tank body 2 is discharged to the outside of the tank body 2. For this purpose, the pump 8A is operated to suck the liquefied carbon dioxide L in the tank body 2 and send it to the outside of the tank body 2 through the discharge pipe 7A. The remaining amount of liquefied carbon dioxide L in the tank body 2 is detected by a liquid level gauge (not shown) provided in the tank body 2. When the remaining amount of liquefied carbon dioxide L in the tank body 2 reaches a preset lower limit value, the operator stops the operation of the pump 8A, and the discharge of the liquefied carbon dioxide L is completed.

[0036] In this state, liquefied carbon dioxide L remains below the pump 8A in the tank body 2. As a result, liquefied carbon dioxide L is stored in the reservoir tank 5A.

[0037] Then, step S12 of heating the inside of the storage tank 5A is performed. Step S12 of heating the inside of the storage tank 5A may be performed immediately after step S11 of discharging the liquefied carbon dioxide L is completed, or may be performed after a suitable time has elapsed.

[0038] In step S12 of heating the inside of the collection tank 5A, after the liquefied carbon dioxide L is discharged to the outside of the tank body 2 in step S11, the inside of the collection tank 5A is heated by the heating unit 10A. In the present embodiment, the heating unit 10A delivers the heating fluid supplied from the heating fluid supply source through the pipe 11A from the outside of the tank body 2 to the inside of the collection tank 5A. The heating fluid is delivered to the inside of the collection tank 5A through the pipe 11A, thereby heating the liquefied carbon dioxide L in the collection tank 5A and the impurities mixed in the liquefied carbon dioxide L. For example, if the temperature of the heating fluid is higher than the boiling point of the liquefied carbon dioxide L and the impurities, the liquefied carbon dioxide L and the impurities in the collection tank 5A can be boiled and actively gasified. In addition, even if the temperature of the heating fluid is lower than the above-mentioned boiling point, the liquefied carbon dioxide L and the impurities in the collection tank 5A can be heated to promote evaporation. The gas obtained by evaporating (gasifying) the liquefied carbon dioxide L and the impurities is discharged to the outside of the tank body 2 through a discharge pipe (not shown) for discharging the gas in the tank body 2 to the outside of the tank body 2 .

[0039] The heating by the heating unit 10A may be performed, for example, until the liquefied carbon dioxide L and impurities accumulated in the storage tank 5A are completely gasified, or until the liquid level of the liquefied carbon dioxide L and impurities in the storage tank 5A drops to a predetermined lower limit level. In addition, the heating by the heating unit 10A may be continued, for example, until a preset time has passed, and then stopped.

[0040] (Effect)

[0041] The liquefied carbon dioxide storage tank 1A of the above-mentioned embodiment is provided with a heating unit 10A capable of heating the inside of the collection tank 5A. After the liquefied carbon dioxide L stored in the tank body 2 is discharged to the outside of the tank body 2, the liquefied carbon dioxide L remaining in the tank body 2 is concentratedly accumulated in the recessed portion 5h of the collection tank 5A recessed from the bottom 2b of the tank body 2. When the inside of the collection tank 5A is heated by the heating unit 10A, the temperature of the liquefied carbon dioxide L in the recessed portion 5h of the collection tank 5A and the impurities mixed in the liquefied carbon dioxide L rises. If the impurities are gasified together with the liquefied carbon dioxide L, it is possible to suppress the impurities from increasing relative to the liquefied carbon dioxide L remaining in the tank body 2. Therefore, it is possible to suppress the influence of the impurities contained in the liquefied carbon dioxide L remaining in the tank body 2 after the liquefied carbon dioxide L is discharged from the tank body 2.

[0042] In the above embodiment, the heating unit 10A can easily heat and gasify the liquefied carbon dioxide in the reservoir 5A by supplying a heating fluid having a higher temperature than the liquefied carbon dioxide L in the tank body 2 from outside the tank body 2 .

[0043] In addition, in the above-mentioned embodiment, the heating fluid fed from the outside of the tank body 2 through the pipe 11A is ejected into the collection tank 5A from the front end portion 11s of the pipe 11A disposed inside the collection tank 5A. The liquefied carbon dioxide L accumulated in the collection tank 5A and the impurities mixed in the liquefied carbon dioxide L are directly heated by the ejected heating fluid. In this way, the liquefied carbon dioxide L and the impurities can be efficiently heated.

[0044] In addition, in the above-mentioned embodiment, the heating unit 10A heats the inside of the storage tank 5A at a temperature higher than the boiling point of the liquefied carbon dioxide L and the impurities. As a result, the liquefied carbon dioxide L and the impurities accumulated in the storage tank 5A can be boiled and actively evaporated. Therefore, the influence of the impurities contained in the liquefied carbon dioxide L remaining in the tank body 2 after the liquefied carbon dioxide L is discharged from the tank body 2 can be more reliably and quickly suppressed.

[0045] In the method S10 for discharging liquefied carbon dioxide L of the above-mentioned embodiment, after discharging the liquefied carbon dioxide L stored in the tank body 2 to the outside of the tank body 2, the inside of the collection tank 5A is heated by the heating unit 10A. As a result, the temperature of the liquefied carbon dioxide L accumulated in the recessed portion 5h of the collection tank 5A recessed from the bottom 2b of the tank body 2 and the impurities mixed in the liquefied carbon dioxide L rises. If the impurities are gasified together with the liquefied carbon dioxide L, it is possible to suppress the impurities from increasing relative to the liquefied carbon dioxide L remaining in the tank body 2. Therefore, the influence of the impurities contained in the liquefied carbon dioxide L remaining in the tank body 2 after the liquefied carbon dioxide L is discharged from the tank body 2 can be suppressed.

[0046] (First Modification of Embodiment)

[0047] In the above embodiment, the collecting tank 5A heated by the heating unit 10A is exemplified, but the position and number of the collecting tanks 5A can be appropriately changed according to the size and shape of the tank body 2 .

[0048] Figure 4 It is a cross-sectional view showing a schematic structure of a liquefied carbon dioxide storage tank according to a modified example of the embodiment of the present disclosure.

[0049] like Figure 4 As shown, in the liquefied carbon dioxide storage tank 1B of this modified example, the pump 8B provided at the front end of the discharge pipe 7B is arranged in the collection tank 5B. The collection tank 5B is integrally provided in the tank body 2 and has a recessed portion 5h recessed from the bottom 2b of the tank body 2. The pump 8B sucks the liquefied carbon dioxide L in the collection tank 5B. Figure 4In the embodiment, the pump 8B is entirely disposed in the reservoir tank 5B, but the present invention is not limited to this arrangement. At least the suction port (not shown) of the pump 8B may be disposed in the reservoir tank 5B.

[0050] In this modification, the front end 11t of the pipe 11B of the heating unit 10B is disposed inside the reservoir 5B together with the pump 8B. The pipe 11B ejects the heating fluid into the reservoir 5B. The liquefied carbon dioxide L in the reservoir 5B is heated by the heating fluid ejected from the pipe 11B.

[0051] In such a structure, the liquefied carbon dioxide L in the tank body 2 is sucked out by the pump 8B and sent out to the outside of the tank body 2 through the discharge pipe 7B. Since the pump 8B is arranged in the collection tank 5B, the pump 8B sucks the liquefied carbon dioxide L accumulated in the collection tank 5B and sends it out to the outside of the tank body 2. Thus, after the liquefied carbon dioxide L in the tank body 2 is discharged to the outside of the tank body 2, the amount of liquefied carbon dioxide L remaining in the tank body 2 can be suppressed.

[0052] Furthermore, by heating the liquefied carbon dioxide L remaining in the storage tank 5B with the heating fluid ejected from the pipe 11B, the amount of the liquefied carbon dioxide L and impurities remaining in the tank body 2 can be further reduced. Therefore, the influence of the impurities contained in the liquefied carbon dioxide L remaining in the tank body 2 after the liquefied carbon dioxide L is discharged from the tank body 2 can be reduced.

[0053] (Second Modification of Embodiment)

[0054] Figure 5 It is a cross-sectional view showing a schematic structure of a liquefied carbon dioxide storage tank according to a second modified example of the embodiment of the present disclosure.

[0055] like Figure 5 As shown, a liquefied carbon dioxide storage tank 1C in this modification includes both the collecting tank 5A shown in the above-mentioned first embodiment and the collecting tank 5B shown in the above-mentioned second embodiment.

[0056] The heating unit 10C in this modified example includes a pipe 11A, a front end 11s of which is disposed inside the collection tank 5A, and a pipe 11B, a front end 11t of which is disposed inside the collection tank 5B. The heating unit 10C heats the inside of the collection tanks 5A and 5B through the pipes 11A and 11B.

[0057] Even in such a configuration, it is possible to suppress the influence of impurities contained in the liquefied carbon dioxide L remaining in the tank body 2 after the liquefied carbon dioxide L is discharged from the tank body 2 .

[0058] Furthermore, in the above-described embodiment and the first and second modified examples of the embodiment, the heating units 10A to 10C include the pipes 11A and 11B for sending the heating fluid into the collection tanks 5A and 5B, but the present invention is not limited thereto.

[0059] For example, the distal ends of the pipes 11A and 11B may be disposed above the collection tanks 5A and 5B so that the heating fluid ejected from the pipes 11A and 11B may be blown from above toward the liquefied carbon dioxide L in the collection tanks 5A and 5B.

[0060] (Other embodiments)

[0061] As mentioned above, although the embodiment of this disclosure is described in detail with reference to drawings, the specific structure is not limited to this embodiment, and design changes etc. which do not deviate from the gist of this disclosure are also included.

[0062] Figure 6 It is a cross-sectional view showing a schematic structure of a liquefied carbon dioxide storage tank according to a third modified example of the embodiment of the present disclosure.

[0063] like Figure 6 As shown, the liquefied carbon dioxide storage tank 1D in the third modified example is provided with a heater 15 as a heating unit 10D. The heater 15 heats the inside of the collection tank 5A. The heater 15 is arranged, for example, to cover the peripheral wall portion 5w of the collection tank 5A. The heater 15 may also be arranged to cover the inner peripheral surface of the recessed portion 5h of the collection tank 5A. The heater 15 heats the liquefied carbon dioxide L in the collection tank 5A.

[0064] Thus, the temperature of the liquefied carbon dioxide L in the recess 5h of the collecting tank 5A and the impurities mixed in the liquefied carbon dioxide L rises by heating the inside of the collecting tank 5A with the heater 15. If the impurities evaporate together with the liquefied carbon dioxide L, the impurities can be suppressed from increasing relative to the liquefied carbon dioxide L remaining in the tank body 2.

[0065] This structure can also suppress the influence of impurities contained in the liquefied carbon dioxide L remaining in the storage tank 5A after the liquefied carbon dioxide L is discharged from the tank body 2. The heater 15 in the third modification can also be used in combination with the structures of the first embodiment and the first and second modifications described above.

[0066] <Note>

[0067] The method S10 of discharging the liquefied carbon dioxide storage tanks 1A to 1D and the liquefied carbon dioxide L described in each embodiment can be understood as follows, for example.

[0068] (1) The liquefied carbon dioxide storage tank 1A to 1D of the first embodiment comprises: a tank body 2 capable of storing liquefied carbon dioxide L; collection tanks 5A and 5B integrally provided in the tank body 2 and having a recess 5h recessed from the bottom 2b of the tank body 2; and heating units 10A to 10D capable of heating the inside of the collection tanks 5A and 5B.

[0069] The liquefied carbon dioxide storage tank 1A to 1D is provided with a heating unit 10A to 10D capable of heating the inside of the collection tank 5A, 5B. After the liquefied carbon dioxide L stored in the tank body 2 is discharged to the outside of the tank body 2, the liquefied carbon dioxide L remaining in the tank body 2 is concentratedly accumulated in the recessed portion 5h of the collection tank 5A, 5B recessed from the bottom 2b of the tank body 2. If the inside of the collection tank 5A, 5B is heated by the heating unit 10A to 10D, the temperature of the liquefied carbon dioxide L in the recessed portion 5h of the collection tank 5A, 5B and the impurities mixed in the liquefied carbon dioxide L rises. If the impurities are gasified together with the liquefied carbon dioxide L, it is possible to suppress the impurities from increasing relative to the liquefied carbon dioxide L remaining in the tank body 2. Therefore, it is possible to suppress the influence of the impurities contained in the liquefied carbon dioxide L remaining in the tank body 2 after the liquefied carbon dioxide L is discharged from the tank body 2.

[0070] (2) The liquefied carbon dioxide storage tank 1A to 1D of the second embodiment is the liquefied carbon dioxide storage tank 1A to 1C of (1), wherein the heating unit 10A to 10D supplies a heating fluid having a higher temperature than the liquefied carbon dioxide L in the tank body 2 from the outside of the tank body 2 .

[0071] Thus, by supplying a heating fluid having a higher temperature than the liquefied carbon dioxide L in the tank body 2 from the outside of the tank body 2 , the heating units 10A to 10D can easily heat the liquefied carbon dioxide in the collection tanks 5A and 5B.

[0072] (3) The liquefied carbon dioxide storage tank 1A~1C of the third scheme is based on the liquefied carbon dioxide storage tank 1A~1C of (2), and the above-mentioned heating part 10A~10C has piping 11A, 11B, and the above-mentioned piping 11A, 11B extends from the outside of the above-mentioned tank body 2 to the inside of the above-mentioned tank body 2, and the front end part 11s is arranged inside the above-mentioned collection tanks 5A, 5B, and the above-mentioned heating fluid is sent into from the outside of the above-mentioned tank body 2.

[0073] Thus, the heating fluid fed from the outside of the tank body 2 through the pipes 11A and 11B is ejected from the front end portions of the pipes 11A and 11B disposed inside the collection tanks 5A and 5B into the collection tanks 5A and 5B. The ejected heating fluid can directly heat the liquefied carbon dioxide L accumulated in the collection tanks 5A and 5B and the impurities mixed in the liquefied carbon dioxide L. In this way, the liquefied carbon dioxide L and the impurities can be effectively heated.

[0074] (4) The liquefied carbon dioxide storage tank 1B, 1C of the fourth scheme is based on the liquefied carbon dioxide storage tank 1B, 1C of (3), and is equipped with: a discharge piping 7B for discharging the liquefied carbon dioxide L in the above-mentioned tank body 2 to the outside of the above-mentioned tank body 2; and a pump 8B, which is arranged in the above-mentioned tank body 2 and sends the above-mentioned liquefied carbon dioxide L in the above-mentioned tank body 2 to the outside of the above-mentioned tank body 2 through the above-mentioned discharge piping 7B, and the above-mentioned pump 8B is arranged in the above-mentioned storage tank 5B together with the above-mentioned piping 11B.

[0075] Thus, the liquefied carbon dioxide L in the tank body 2 is delivered to the outside of the tank body 2 by the pump 8B through the discharge pipe 7B. When such a pump 8B is arranged in the collection tank 5B, the pump 8B sucks the liquefied carbon dioxide L accumulated in the collection tank 5B and delivers it to the outside of the tank body 2. Thus, the amount of liquefied carbon dioxide L remaining in the tank body 2 after the liquefied carbon dioxide L in the tank body 2 is discharged to the outside of the tank body 2 can be suppressed.

[0076] Furthermore, by heating the liquefied carbon dioxide L remaining in the storage tank 5B with the heating fluid ejected from the pipe 11B, the amount of the liquefied carbon dioxide L remaining in the tank body 2 can be further suppressed.

[0077] (5) A liquefied carbon dioxide storage tank 1D according to a fifth aspect is the liquefied carbon dioxide storage tank 1D according to any one of (1) to (4), wherein the heating unit 10D includes a heater 15 for heating the inside of the collecting tank 5A.

[0078] Thus, the temperature of the liquefied carbon dioxide L in the recess 5h of the collecting tank 5A and the impurities mixed in the liquefied carbon dioxide L rises by heating the inside of the collecting tank 5A with the heater 15. If the impurities evaporate together with the liquefied carbon dioxide L, the impurities can be suppressed from increasing relative to the liquefied carbon dioxide L remaining in the tank body 2.

[0079] (6) The liquefied carbon dioxide storage tank 1A~1D of the sixth embodiment is any one of the liquefied carbon dioxide storage tanks 1A~1D in (1) to (5), and the above-mentioned heating unit 10A~10D heats the above-mentioned storage tanks 5A, 5B at a temperature higher than the boiling point of the above-mentioned liquefied carbon dioxide L in the above-mentioned tank body 2 and the impurities mixed in the above-mentioned liquefied carbon dioxide L.

[0080] Thus, the heating units 10A to 10D heat the inside of the storage tanks 5A and 5B at a temperature higher than the boiling point of the liquefied carbon dioxide L and the impurities, so that the liquefied carbon dioxide L and the impurities accumulated in the storage tanks 5A and 5B can be boiled and actively evaporated. Therefore, the influence of the impurities contained in the liquefied carbon dioxide L remaining in the tank body 2 after the liquefied carbon dioxide L is discharged from the tank body 2 can be more reliably and quickly suppressed.

[0081] (7) The seventh method S10 for discharging liquefied carbon dioxide L is a method S10 for discharging the liquefied carbon dioxide L stored in the tank body 2 from the inside of any one of the liquefied carbon dioxide storage tanks 1A to 1D of (1) to (6), and the method S10 for discharging liquefied carbon dioxide L includes the following steps: a step S11 of discharging the liquefied carbon dioxide L stored in the tank body 2 to the outside of the tank body 2; and a step S12 of heating the storage tanks 5A, 5B after discharging the liquefied carbon dioxide L to the outside of the tank body 2.

[0082] Thus, after the liquefied carbon dioxide L stored in the tank body 2 is discharged to the outside of the tank body 2, the inside of the collection tanks 5A and 5B is heated by the heating parts 10A to 10D. As a result, the temperature of the liquefied carbon dioxide L accumulated in the recessed part 5h of the collection tanks 5A and 5B recessed from the bottom 2b of the tank body 2 and the impurities mixed in the liquefied carbon dioxide L rises. If the impurities evaporate together with the liquefied carbon dioxide L, it is possible to suppress the impurities from increasing relative to the liquefied carbon dioxide L remaining in the tank body 2. Therefore, the influence of the impurities contained in the liquefied carbon dioxide L remaining in the tank body 2 after the liquefied carbon dioxide L is discharged from the tank body 2 can be suppressed.

[0083] Industrial Applicability

[0084] According to the liquefied carbon dioxide storage tank and the method for discharging liquefied carbon dioxide of the above-described aspect, it is possible to suppress the influence of impurities contained in the liquefied carbon dioxide remaining in the tank body after the liquefied carbon dioxide is discharged from the tank body.

[0085] Description of Reference Numerals

[0086] 1A~1D…liquefied carbon dioxide storage tank 2…tank body 2b…bottom 3…cylindrical portion 4…end plate portion 5A, 5B…collecting tank 5d…bottom plate portion 5h…recess 5w…peripheral wall portion 7A, 7B…discharge piping 8A, 8B…pump 10A~10D…heating portion 11A, 11B…piping 11s, 11t…front end portion 15…heater Dc…central axis direction Dv…up and down direction L…liquefied carbon dioxide S10…discharging method S11…step of discharging liquefied carbon dioxide S12…step of heating the inside of the collecting tank.

Claims

1. A liquefied carbon dioxide storage tank, comprising: A tank body capable of storing liquefied carbon dioxide; a collecting tank, which is integrally provided on the tank body and has a recessed portion sunken from the bottom of the tank body; and The heating unit is capable of heating the inside of the collecting tank.

2. The liquefied carbon dioxide storage tank according to claim 1, wherein: The heating unit supplies a heating fluid having a higher temperature than the liquefied carbon dioxide in the tank body from the outside of the tank body.

3. The liquefied carbon dioxide storage tank according to claim 2, wherein: The heating unit includes a pipe extending from the outside of the tank body to the inside of the tank body, a front end of which is disposed inside the collecting tank and feeds the heating fluid from the outside of the tank body.

4. The liquefied carbon dioxide storage tank according to claim 3, wherein: The liquefied carbon dioxide storage tank has: a discharge pipe for discharging the liquefied carbon dioxide in the tank body to the outside of the tank body; and a pump, disposed in the tank body, for delivering the liquefied carbon dioxide in the tank body to the outside of the tank body through the discharge pipe, The pump is disposed in the reservoir tank together with the pipe.

5. The liquefied carbon dioxide storage tank according to claim 1 or 2, wherein: The heating unit includes a heater that heats the inside of the collecting tank.

6. The liquefied carbon dioxide storage tank according to claim 1 or 2, wherein: The heating unit heats the interior of the storage tank at a temperature higher than a boiling point of the liquefied carbon dioxide in the tank body and impurities mixed in the liquefied carbon dioxide.

7. A method for discharging liquefied carbon dioxide, the method comprising discharging the liquefied carbon dioxide stored in the tank body from the inside of the liquefied carbon dioxide storage tank according to claim 1 or 2, The method for discharging liquefied carbon dioxide comprises the following steps: a step of discharging the liquefied carbon dioxide stored in the tank body to the outside of the tank body; and The step of heating the inside of the tank body after discharging the liquefied carbon dioxide to the outside of the tank body.

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