JP2024030333A - Liquefied carbon dioxide facility, and dry ice formation condition estimation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively restrain the formation of dry ice even if impurities are included in liquefied carbon dioxide.

SOLUTION: A liquefied carbon dioxide facility comprises: a tank capable of storing liquefied carbon dioxide; a pipe connected to the tank, and through which liquefied carbon dioxide can flow; a pressure sensor for detecting a pressure in a region in which the liquefied carbon dioxide exists inside at least one of the tank and the pipe; a temperature sensor for detecting a temperature in the region in which the liquefied carbon dioxide exists; and an estimation unit for estimating a dry ice formation condition in the region in which the liquefied carbon dioxide exists, on the basis of detection results of the pressure sensor and the temperature sensor.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present disclosure relates to a liquefied carbon dioxide facility and a method for estimating the production status of dry ice.

For example, the tank (fuel tank) disclosed in Patent Document 1 includes piping (pipeline) for loading liquefied natural gas (LNG) into the tank and piping (pipeline) for discharging liquefied gas from the tank. ).

When the pressure of liquefied carbon dioxide decreases in a tank containing liquefied carbon dioxide or in piping through which liquefied carbon dioxide flows, liquefied carbon dioxide solidifies and produces dry ice for the following reasons. There is a possibility that
Liquefied carbon dioxide has a triple point pressure (triple point pressure) where gas, liquid, and solid phases coexist, which is higher than that of LNG or LPG (liquefied petroleum gas), making tank operation difficult during operation. The difference from the pressure may be small. In this case, depending on the tank operating pressure (tank design pressure), the pressure of the liquefied carbon dioxide will partially decrease, and the pressure of the liquefied carbon dioxide will drop below the triple point pressure, causing flash evaporation of the liquefied carbon dioxide. Due to the latent heat of vaporization, there is a possibility that the temperature of liquefied carbon dioxide will decrease and dry ice will be produced.
When dry ice is generated in this way, the flow of liquefied carbon dioxide within the piping may be obstructed.

For this reason, in liquefied carbon dioxide equipment equipped with tanks and piping that contain liquefied carbon dioxide, the pressure in areas where liquefied carbon dioxide exists, such as inside tanks and piping, must be adjusted to suppress the formation of dry ice. It is necessary to monitor the pressure with a pressure sensor and operate the equipment while managing the pressure.

Special table 2018-528119 publication

By the way, liquefied carbon dioxide, which is obtained by recovering carbon dioxide from exhaust gases generated in various plants and the like, often contains various impurities. The temperature and pressure of the triple point of liquefied carbon dioxide containing such impurities may be different from the temperature and pressure of the triple point of liquefied carbon dioxide that does not contain impurities. Therefore, even in a pressure environment higher than the triple point of liquefied carbon dioxide that does not contain impurities, flash evaporation occurs with liquefied carbon dioxide that contains impurities. Even if pressure sensors are used to monitor the pressure in areas where carbon dioxide exists, dry ice may still be generated.

The present disclosure has been made to solve the above problems, and includes liquefied carbon dioxide equipment that can effectively suppress the production of dry ice even when liquefied carbon dioxide contains impurities; The purpose is to provide a method for estimating the production status of dry ice.

In order to solve the above problems, a liquefied carbon dioxide facility according to the present disclosure includes a tank, piping, a pressure sensor, a temperature sensor, and an estimator. The tank can store liquefied carbon dioxide. The piping is connected to the tank so that the liquefied carbon dioxide can flow therethrough. The pressure sensor detects a pressure in a region where the liquefied carbon dioxide exists inside at least one of the tank and the piping. The temperature sensor detects the temperature of the region where the liquefied carbon dioxide is present. The estimation unit estimates the state of dry ice production in the region where the liquefied carbon dioxide exists based on the detection results of the pressure sensor and the temperature sensor.

The liquefied carbon dioxide equipment according to the present disclosure includes a tank, piping, a solid detection section, and an estimation section. The tank can store liquefied carbon dioxide. The piping is connected to the tank so that the liquefied carbon dioxide can flow therethrough. The solid detection unit detects solids mixed in the liquefied carbon dioxide in a region where the liquefied carbon dioxide exists inside at least one of the tank and the piping. The estimating unit estimates the production status of dry ice in the region where the liquefied carbon dioxide exists based on the detection status of the solid by the solid detection unit.

A method for estimating the production status of dry ice according to the present disclosure is a method for estimating the production status of dry ice in the liquefied carbon dioxide equipment described above. The method for estimating the production status of dry ice includes the steps of detecting pressure and temperature, and estimating the production status of dry ice. In the step of detecting the pressure and temperature, the pressure and temperature of the region where the liquefied carbon dioxide is present are detected. The step of estimating the production status of dry ice estimates the production status of dry ice in the region where the liquefied carbon dioxide exists based on the detection results of the pressure and the temperature.

A method for estimating the production status of dry ice according to the present disclosure is a method for estimating the production status of dry ice in the liquefied carbon dioxide equipment described above. The method for estimating the production status of dry ice includes the steps of detecting the presence or absence of a solid, and estimating the production status of dry ice. The step of detecting the presence or absence of the solid includes detecting the presence or absence of a solid mixed in the liquefied carbon dioxide in the region where the liquefied carbon dioxide exists. In the step of estimating the state of production of dry ice, the state of production of dry ice in the region where the liquefied carbon dioxide exists is estimated based on the detection result of the solid.

According to the liquefied carbon dioxide equipment and dry ice production status estimation method of the present disclosure, even if liquefied carbon dioxide contains impurities, the production of dry ice can be effectively suppressed.

1 is a diagram showing a schematic configuration of a liquefied carbon dioxide facility according to a first embodiment of the present disclosure. FIG. 2 is a cross-sectional view showing a pressure sensor and a temperature sensor provided in piping according to first and second embodiments of the present disclosure. 1 is a diagram showing a hardware configuration of a control device according to first to third embodiments of the present disclosure. FIG. FIG. 2 is a functional block diagram of a control device according to first and second embodiments of the present disclosure. It is a flowchart which shows the procedure of the production situation estimation method of dry ice concerning a first embodiment of this indication. It is a diagram showing a schematic configuration of a liquefied carbon dioxide facility according to a second embodiment of the present disclosure. FIG. 7 is a diagram showing a solid state detection unit according to second and third embodiments of the present disclosure. It is a flowchart which shows the procedure of the production situation estimation method of dry ice concerning a second embodiment of this indication. It is a diagram showing a schematic configuration of a liquefied carbon dioxide facility according to a third embodiment of the present disclosure. FIG. 3 is a functional block diagram of a control device according to a third embodiment of the present disclosure. It is a flowchart which shows the procedure of the production situation estimation method of dry ice concerning a third embodiment of this indication.

<First embodiment>
Hereinafter, a liquefied carbon dioxide facility and a method for estimating the production status of dry ice according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 11.
(Overall configuration of liquefied carbon dioxide equipment)
As shown in FIG. 1, liquefied carbon dioxide equipment 1A in this embodiment includes at least a tank 2, piping 10, a pressure sensor 20, a temperature sensor 30, and a control device 60A.

Tank 2 can store liquefied carbon dioxide. The liquefied carbon dioxide stored in the tank 2 may contain impurities. In the following description, a liquid containing liquefied carbon dioxide and impurities mixed in the liquefied carbon dioxide will be referred to as a stored liquid L. The tank 2 is installed in the hull of a ship, the main body of an offshore floating facility, a liquefied gas storage facility on land, or the like.

The tank 2 has, for example, a cylindrical shape. The tank 2 includes a cylindrical portion 3 and an end plate portion 4. The cylindrical portion 3 extends in the central axis direction Dc in which its central axis extends. In this embodiment, the central axis direction Dc is a direction perpendicular to the vertical direction Dv. The central axis direction Dc may coincide with the horizontal direction, or may be slightly inclined with respect to the horizontal direction. In this embodiment, the cylindrical portion 3 is formed in a cylindrical shape, and has a circular cross-sectional shape perpendicular to the central axis direction Dc. The end plate portions 4 are arranged at both ends of the cylindrical portion 3 in the central axis direction Dc. Each mirror plate portion 4 has a hemispherical shape and closes the openings on both sides of the cylindrical portion 3 in the central axis direction Dc.
Note that the tank 2 may be arranged so that its center axis direction Dc coincides with the vertical direction Dv. Further, the tank 2 is not limited to a cylindrical shape, and may have other shapes such as a spherical shape or a rectangular shape.

The liquefied carbon dioxide equipment 1A of this embodiment includes, for example, a loading pipe 11 and a discharging pipe 12 as the pipe 10. The loading pipe 11 and the discharging pipe 12 are each connected to the tank 2. A storage liquid L of liquefied carbon dioxide can flow through the loading pipe 11 and the discharging pipe 12 as the pipe 10, respectively. The piping 10 is not limited to the loading piping 11 and the discharging piping 12, as long as it is connected to the tank 2, and may be piping used for other purposes.

The loading pipe 11 is a pipe for loading the stored liquid L of liquefied carbon dioxide supplied from the outside into the tank 2 . For example, the loading pipe 11 penetrates the top of the tank 2 and extends inside and outside the tank 2 from above to below in the vertical direction Dv. The tip of the loading pipe 11 (in other words, the lower end in the up-down direction Dv) is open at the lower part of the tank 2 and faces downward.
The loading pipe 11 is provided with an on-off valve 15 . The on-off valve 15 is arranged outside the tank 2, for example. The on-off valve 15 opens and closes the loading pipe 11.

The discharging pipe 12 is a pipe for discharging the stored liquid L in the tank 2 to the outside of the tank 2. For example, the discharge pipe 12 penetrates the top of the tank 2 from the outside of the tank 2 and extends into the inside of the tank 2 . The distal end of the dispensing pipe 12 is arranged at the lower part of the tank 2 . A pump 13 is provided at the tip of the delivery pipe 12. Pump 13 is arranged within tank 2. The pump 13 sucks in the stored liquid L of liquefied carbon dioxide in the tank 2 and sends it out of the tank 2 through the discharge pipe 12 .
The discharge pipe 12 is provided with an on-off valve 16 . The on-off valve 16 is arranged outside the tank 2, for example. The on-off valve 16 opens and closes the delivery pipe 12.

The inside of the tank 2, the inside of the loading pipe 11, and the inside of the discharge pipe 12 are areas where liquefied carbon dioxide exists.

(Pressure sensor, temperature sensor configuration)
The pressure sensor 20 detects the pressure in the area where liquefied carbon dioxide exists inside the tank 2 and inside the piping 10. In this embodiment, the pressure sensor 20 includes, for example, a first pressure sensor 20A to a fifth pressure sensor 20E.

Among these, the first pressure sensor 20A, the second pressure sensor 20B, and the third pressure sensor 20C detect the pressure of each part within the tank 2. The first pressure sensor 20A detects the upper pressure inside the tank 2. The second pressure sensor 20B detects the pressure at the bottom inside the tank 2. The third pressure sensor 20C detects the pressure in the middle part of the tank 2 above the bottom part. The number and arrangement of pressure sensors 20 provided in the tank 2 are not limited in any way, and other pressure sensors 20 may be provided in addition to the first pressure sensor 20A, second pressure sensor 20B, and third pressure sensor 20C. good. Moreover, some of the first pressure sensor 20A, the second pressure sensor 20B, and the third pressure sensor 20C may be omitted.

FIG. 2 is a cross-sectional view showing a pressure sensor and a temperature sensor provided in piping according to an embodiment of the present disclosure.
As shown in FIG. 2, the fourth pressure sensor 20D and the fifth pressure sensor 20E detect the pressure at each part within the pipe 10. The fourth pressure sensor 20D and the fifth pressure sensor 20E are provided in each of the loading pipe 11 and the discharging pipe 12. The fourth pressure sensor 20D detects the pressure near the pipe wall inside the pipe 10. The fifth pressure sensor 20E detects the pressure in the middle part of the pipe 10 away from the pipe wall.
The number and arrangement of pressure sensors provided in the pipe 10 are not limited at all, and other pressure sensors 20 may be provided in addition to the fourth pressure sensor 20D and the fifth pressure sensor 20E. Further, a plurality of sets of the fourth pressure sensor 20D and the fifth pressure sensor 20E may be provided at intervals in the extending direction of the pipe 10.

The temperature sensor 30 detects the temperature of the region inside the tank 2 and the piping 10 where liquefied carbon dioxide exists. In this embodiment, the temperature sensor 30 includes, for example, a first temperature sensor 30A to a fifth temperature sensor 30E.

As shown in FIG. 1, the first temperature sensor 30A, the second temperature sensor 30B, and the third temperature sensor 30C detect the temperature of the liquefied carbon dioxide stored liquid L at each part of the tank 2. The first temperature sensor 30A detects the temperature of the upper part of the tank 2. The second temperature sensor 30B detects the temperature at the bottom inside the tank 2. The third temperature sensor 30C detects the temperature of the middle part above the bottom part of the tank 2. For example, a thermal camera or the like can be used as the first temperature sensor 30A and the second temperature sensor 30B. For example, a thermocouple or the like can be used as the third temperature sensor 30C.
The number and arrangement of temperature sensors 30 provided in the tank 2 are not limited in any way, and other temperature sensors 30 may be provided in addition to the first temperature sensor 30A, second temperature sensor 30B, and third temperature sensor 30C. good. Moreover, some of the first temperature sensor 30A, the second temperature sensor 30B, and the third temperature sensor 30C may be omitted.

As shown in FIG. 2, the fourth temperature sensor 30D and the fifth temperature sensor 30E detect the temperature of each part within the pipe 10. The fourth temperature sensor 30D and the fifth temperature sensor 30E are provided in each of the loading pipe 11 and the discharging pipe 12. The fourth temperature sensor 30D detects the pressure near the pipe wall of the pipe 10. The fifth temperature sensor 30E detects the temperature of an intermediate portion within the pipe 10 that is away from the pipe wall. For example, a thermal camera or the like can be used as the fourth temperature sensor 30D. As the fifth temperature sensor 30E, for example, a thermocouple or the like can be used.
The number and arrangement of temperature sensors provided in the pipe 10 are not limited at all, and other temperature sensors 30 may be provided in addition to the fourth temperature sensor 30D and the fifth temperature sensor 30E. Further, a plurality of sets of the fourth temperature sensor 30D and the fifth temperature sensor 30E may be provided at intervals in the extending direction of the pipe 10.

(Hardware configuration diagram)
FIG. 3 is a diagram showing a hardware configuration of a control device according to an embodiment of the present disclosure.
As shown in FIG. 3, the control device 60A includes a CPU 61 (Central Processing Unit), a ROM 62 (Read Only Memory), a RAM 63 (Random Access Memory), a storage 64 such as an HDD (Hard Disk Drive), and a signal. Includes a transmitting/receiving module 65 It's a computer.

(Functional block diagram)
FIG. 4 is a functional block diagram of a control device according to an embodiment of the present disclosure.
As shown in FIG. 4, the CPU 61 of the control device 60A controls each of the signal input section 70, storage section 71, estimation section 72A, control section 73A, and output section 75 by executing a program stored in advance in the storage 64 or the like. Realize functional configuration. The control device 60A estimates the state of dry ice production in the region where liquefied carbon dioxide exists based on the detection results of the pressure sensor 20 and the temperature sensor 30.

The signal input unit 70 receives detection signals from the pressure sensor 20 and the temperature sensor 30 via the signal transmission/reception module 65.

The storage unit 71 stores triple point information based on the composition of the liquefied carbon dioxide storage liquid L stored in the tank 2. The stored liquid L of liquefied carbon dioxide contains liquefied carbon dioxide and impurities mixed in the liquefied carbon dioxide. The pressure and temperature at the triple point of such stored liquid L are different from those of liquefied carbon dioxide containing no impurities. Further, the pressure and temperature at the triple point differ depending on the amount of impurities relative to the liquefied carbon dioxide in the stored liquid L. For this reason, before storing the liquefied carbon dioxide storage liquid L in the tank 2, analyze the composition of the storage liquid L and obtain information on the triple point of the storage liquid L, including the pressure and temperature at the triple point. . The acquired triple point information is stored in the storage unit 71.

The estimation unit 72A estimates the state of dry ice production in the region where liquefied carbon dioxide exists based on the detection results of the pressure sensor 20 and the temperature sensor 30. The estimation unit 72A determines whether or not the inside of the tank 2 and the pipe 10 are liquefied by the pressure sensors 20 (first pressure sensor 20A to fifth pressure sensor 20E) based on the detection signal from the pressure sensor 20 received by the signal input unit 70. A detection result of the pressure of the stored liquid L in a region where carbon dioxide exists is obtained. The estimating unit 72A is configured to estimate the temperature at each part in the tank 2 and the piping 10 by the temperature sensors 30 (first temperature sensor 30A to fifth temperature sensor 30E) based on the detection signal from the temperature sensor 30 received by the signal input unit 70. , obtain the detection result of the temperature of the stored liquid L in the region where liquefied carbon dioxide exists.

The estimation unit 72A estimates the state of dry ice production based on the detection results of the pressure sensor 20 and the temperature sensor 30 and the triple point information stored in the storage unit 71. The estimating unit 72A estimates the stored liquid L based on the obtained pressure and temperature of the stored liquid L in the region where liquefied carbon dioxide exists and the triple point information of the stored liquid L stored in the storage unit 71. Compare the pressure and temperature at the triple point. The estimating unit 72A calculates that the pressure of the stored liquid L in the region where liquefied carbon dioxide exists is lower than the pressure at the triple point of the stored liquid L, and the temperature of the stored liquid L in the region where liquefied carbon dioxide exists is lower than the pressure of the stored liquid L in the region where liquefied carbon dioxide exists. It is estimated that when the temperature is higher than the triple point temperature of the liquid L, dry ice is generated in the stored liquid L in a region where liquefied carbon dioxide exists.

The control unit 73A controls the operation of the pump 13 and the on-off valves 15 and 16 in order to suppress the production of dry ice based on the dry ice production status estimated by the estimation unit 72A.
When the estimator 72A estimates that dry ice is being generated, the controller 73A stops the operation of the pump 13, for example, to suppress the pressure drop in the tank 2. In addition, when the estimator 72A estimates that dry ice is generated, the control unit 73A increases the rotational speed of the pump 13 to increase the liquefied carbon dioxide stored liquid L in the pipe 10, for example. It may also be pressurized.
Further, the control unit 73A may close the on-off valves 15 and 16 to recover the static pressure in the pipe 10 when the estimation unit 72A estimates that dry ice is generated.
The control unit 73A may control all of the operations of the pump 13 and the on-off valves 15 and 16, or only some of them. Further, the control unit 73A may control the operations of the pump 13 and the on-off valves 15 and 16 at the same time, or may control the operations at different timings. In addition to the above, the control unit 73A may supply pressurized fluid to a region where liquefied carbon dioxide exists.

(Steps for estimating dry ice production status)
FIG. 5 is a flowchart illustrating the procedure of a method for estimating the production status of dry ice according to an embodiment of the present disclosure.
As shown in FIG. 5, the method S10 for estimating the production status of dry ice according to the present embodiment includes a step S11 of detecting pressure and temperature, a step S12 of estimating the production status of dry ice, and a step S12 of estimating the production status of dry ice. The process includes a step S13 in which it is determined whether or not the situation is such that a situation exists, and a step S14 in which the operation of the pump and the on-off valve is controlled.

In step S11 of detecting the pressure and temperature, the pressure sensor 20 and the temperature sensor 30 detect the pressure and temperature of the region in the tank 2 and the pipe 10 where liquefied carbon dioxide exists. For this purpose, the first pressure sensor 20A, the second pressure sensor 20B, and the third pressure sensor 20C detect the pressure of each part within the tank 2. Further, a fourth pressure sensor 20D and a fifth pressure sensor 20E detect the pressure of each part within the pipe 10. Further, a first temperature sensor 30A, a second temperature sensor 30B, and a third temperature sensor 30C detect the temperature of each part within the tank 2. Further, a fourth temperature sensor 30D and a fifth temperature sensor 30E detect the temperature of each part within the pipe 10.
Detection signals indicating the detection results of the pressure sensor 20 and temperature sensor 30 are transmitted to the control device 60A.

In step S12 of estimating the state of production of dry ice, the state of production of dry ice in the region where liquefied carbon dioxide exists is estimated based on the pressure and temperature detection results. For this purpose, the signal input unit 70 of the control device 60A receives detection signals from the pressure sensor 20 and the temperature sensor 30. The estimating unit 72A then estimates the inside of the tank 2 and the piping 10 by the pressure sensors 20 (first pressure sensor 20A to fifth pressure sensor 20E) based on the detection signal from the pressure sensor 20 received by the signal input unit 70. The detection results of the pressure of the stored liquid L in each part are acquired. In addition, the estimating unit 72A calculates the temperature inside the tank 2 and inside the piping 10 by the temperature sensors 30 (first temperature sensor 30A to fifth temperature sensor 30E) based on the detection signal from the temperature sensor 30 received by the signal input unit 70. The detection results of the temperature of the stored liquid L in each part are acquired. Further, the estimation unit 72A acquires information on the triple point of the stored liquid L stored in the storage unit 71.

In step S12 of estimating the production status of dry ice, the estimating unit 72A further estimates whether the dry ice is Estimate the generation status of. This is based on the pressure and temperature of the stored liquid L in the area where liquefied carbon dioxide is present, acquired by the estimating unit 72A, and the triple point information of the stored liquid L stored in the storage unit 71. Compare the pressure and temperature at the triple point of L. Here, the estimation unit 72A determines that the pressure of the stored liquid L in the area where liquefied carbon dioxide exists is lower than the pressure at the triple point of the stored liquid L, and the temperature of the stored liquid L in the area where liquefied carbon dioxide exists. is higher than the temperature of the triple point of the stored liquid L, it is estimated that dry ice is generated in the stored liquid L in a region where liquefied carbon dioxide exists.

In step S13 of determining whether the situation is such that dry ice is generated, it is determined whether the situation is such that dry ice is generated in the stored liquid L in the region where liquefied carbon dioxide exists in step S12. As a result of this determination, if it is determined that dry ice is not generated in the stored liquid L in the area where liquefied carbon dioxide exists (No in step S13), the process returns to step S11.
On the other hand, if it is determined that dry ice is generated in the stored liquid L in the region where liquefied carbon dioxide exists (Yes in step S13), the process proceeds to step S14.

In step S14 for controlling the operation of the pump and on-off valves, if it is determined in step S13 that dry ice is generated in the stored liquid L, the control unit 73A controls the operation of the pump 13 and on-off valves 15 and 16. control the behavior of For example, the control unit 73A stops the operation of the pump 13 to suppress a drop in pressure within the tank 2. Further, the control unit 73A may increase the rotation speed of the pump 13 to pressurize the stored liquid L (liquefied carbon dioxide) in the pipe 10. Further, the control unit 73A closes the on-off valves 15 and 16 to restore the static pressure within the pipe 10. This aims to suppress the growth of dry ice and eliminate the generated dry ice.

(effect)
In the liquefied carbon dioxide equipment 1A of the above embodiment, the pressure sensor 20 and the temperature sensor 30 detect the pressure and temperature of a region where liquefied carbon dioxide exists inside at least one of the tank 2 and the piping 10. As a result, even if the liquefied carbon dioxide contains impurities, the estimation unit 72A calculates the pressure and temperature of the region where the liquefied carbon dioxide exists based on the detection results of the pressure sensor 20 and the temperature sensor 30. However, it can be compared with the pressure and temperature at the triple point of liquefied carbon dioxide containing impurities. This makes it possible to estimate with high accuracy the state of dry ice production in the region where liquefied carbon dioxide exists. Therefore, even if the liquefied carbon dioxide contains impurities, the production of dry ice can be effectively suppressed.

Furthermore, in the embodiment described above, the storage unit 71 stores triple point information based on the composition of the liquefied carbon dioxide storage liquid L stored in the tank 2. The estimation unit 72A estimates the state of dry ice production based on the detection results of the pressure sensor 20 and the temperature sensor 30 and the triple point information stored in the storage unit 71. Thereby, the state of dry ice production in the stored liquid L, which is liquefied carbon dioxide containing impurities, can be estimated with higher accuracy.

Furthermore, in the embodiment described above, the control unit 73A controls the operation of the pump 13 based on the dry ice production status estimated by the estimation unit 72A. As a result, when the estimation unit 72A estimates that dry ice is generated, the operation of the pump 13 is controlled to perform processes such as suppressing the generation of dry ice and eliminating the generated dry ice. can do. Examples of controlling the operation of the pump 13 include stopping the operation of the pump 13 and pressurizing liquid carbon dioxide by the pump 13.

Furthermore, in the embodiment described above, when the estimating unit 72A estimates that the situation is such that dry ice is generated, the on-off valves 15 and 16 are closed, thereby suppressing the generation of dry ice.

In the dry ice production state estimation method S10 of the above embodiment, the dry ice production state in the region where liquefied carbon dioxide exists is estimated based on the pressure and temperature detection results in the region where liquefied carbon dioxide exists. By comparing the pressure and temperature detection results in the area where liquefied carbon dioxide exists with the pressure and temperature at the triple point of liquefied carbon dioxide containing impurities, it is possible to determine if liquefied carbon dioxide contains impurities. However, the production of dry ice can be effectively suppressed.

<Second embodiment>
Next, a second embodiment of the liquefied carbon dioxide equipment and method for estimating the production status of dry ice according to the present disclosure will be described.
(Overall configuration of liquefied carbon dioxide equipment)
FIG. 6 is a diagram showing a schematic configuration of a liquefied carbon dioxide facility according to a second embodiment of the present disclosure.
As shown in FIG. 6, the liquefied carbon dioxide equipment 1B in this embodiment includes at least a tank 2, a pipe 10, a pressure sensor 20, a temperature sensor 30, a solid detection section 50B, and a control device 60B. ing.

Tank 2 can store liquefied carbon dioxide. The liquefied carbon dioxide stored in the tank 2 may contain impurities. In the following description, similarly to the first embodiment, a liquid containing liquefied carbon dioxide and impurities mixed in the liquefied carbon dioxide will be referred to as a stored liquid L. The tank 2 is installed in the hull of a ship, the main body of an offshore floating facility, a liquefied gas storage facility on land, or the like.

The tank 2 has, for example, a cylindrical shape. The tank 2 includes a cylindrical portion 3 and an end plate portion 4. The cylindrical portion 3 extends in the central axis direction Dc in which its central axis extends. In this second embodiment, the central axis direction Dc is a direction perpendicular to the up-down direction Dv. The central axis direction Dc may coincide with the horizontal direction, or may be slightly inclined with respect to the horizontal direction. In this embodiment, the cylindrical portion 3 is formed in a cylindrical shape, and has a circular cross-sectional shape perpendicular to the central axis direction Dc. The end plate portions 4 are arranged at both ends of the cylindrical portion 3 in the central axis direction Dc. Each mirror plate portion 4 has a hemispherical shape and closes the openings on both sides of the cylindrical portion 3 in the central axis direction Dc.
Note that the tank 2 may be arranged so that its center axis direction Dc coincides with the vertical direction Dv. Further, the tank 2 is not limited to a cylindrical shape, and may have other shapes such as a spherical shape or a rectangular shape.

The liquefied carbon dioxide equipment 1B of the second embodiment includes, as the piping 10, a loading piping 11 and a discharging piping 12, for example. The loading pipe 11 and the discharging pipe 12 are each connected to the tank 2. A storage liquid L of liquefied carbon dioxide can flow through the loading pipe 11 and the discharging pipe 12 as the pipe 10, respectively. The piping 10 is not limited to the loading piping 11 and the discharging piping 12, as long as it is connected to the tank 2, and may be piping used for other purposes.

The loading pipe 11 is a pipe for loading the stored liquid L of liquefied carbon dioxide supplied from the outside into the tank 2 . For example, the loading pipe 11 penetrates the top of the tank 2 and extends inside and outside the tank 2 from above to below in the vertical direction Dv. The tip of the loading pipe 11 (in other words, the lower end in the up-down direction Dv) is open at the lower part of the tank 2 and faces downward.
The loading pipe 11 is provided with an on-off valve 15 . The on-off valve 15 is arranged outside the tank 2, for example. The on-off valve 15 opens and closes the loading pipe 11.

The dispensing piping 12 is a piping for discharging the stored liquid L in the tank 2 to the outside of the tank 2. It is extending. The distal end of the dispensing pipe 12 is arranged at the lower part of the tank 2 . A pump 13 is provided at the tip of the delivery pipe 12. Pump 13 is arranged within tank 2. The pump 13 sucks in the stored liquid L of liquefied carbon dioxide in the tank 2 and sends it out of the tank 2 through the discharge pipe 12 .
The discharge pipe 12 is provided with an on-off valve 16 . The on-off valve 16 is arranged outside the tank 2, for example. The on-off valve 16 opens and closes the delivery pipe 12.

The inside of the tank 2, the inside of the loading pipe 11, and the inside of the discharge pipe 12 are areas where liquefied carbon dioxide exists.

(Pressure sensor, temperature sensor configuration)
The pressure sensor 20 detects the pressure in the area where liquefied carbon dioxide exists inside the tank 2 and inside the piping 10. In this embodiment, the pressure sensor 20 includes, for example, a first pressure sensor 20A to a fifth pressure sensor 20E.

Among these, the first pressure sensor 20A, the second pressure sensor 20B, and the third pressure sensor 20C detect the pressure of each part within the tank 2. The first pressure sensor 20A detects the pressure at the top of the tank 2. The second pressure sensor 20B detects the pressure at the bottom inside the tank 2. The third pressure sensor 20C detects the pressure in the middle part of the tank 2 above the bottom part. The number and arrangement of pressure sensors 20 provided in the tank 2 are not limited in any way, and other pressure sensors 20 may be provided in addition to the first pressure sensor 20A, second pressure sensor 20B, and third pressure sensor 20C. good. Moreover, some of the first pressure sensor 20A, the second pressure sensor 20B, and the third pressure sensor 20C may be omitted.

FIG. 2 is a cross-sectional view showing a pressure sensor and a temperature sensor provided in piping according to an embodiment of the present disclosure.
As shown in FIG. 2, the fourth pressure sensor 20D and the fifth pressure sensor 20E detect the pressure at each part within the pipe 10. The fourth pressure sensor 20D and the fifth pressure sensor 20E are provided in each of the loading pipe 11 and the discharging pipe 12. The fourth pressure sensor 20D detects the pressure near the pipe wall inside the pipe 10. The fifth pressure sensor 20E detects the pressure in the middle part of the pipe 10 away from the pipe wall.
The number and arrangement of pressure sensors provided in the pipe 10 are not limited at all, and other pressure sensors 20 may be provided in addition to the fourth pressure sensor 20D and the fifth pressure sensor 20E. Further, a plurality of sets of the fourth pressure sensor 20D and the fifth pressure sensor 20E may be provided at intervals in the extending direction of the pipe 10.

The temperature sensor 30 detects the temperature of the region inside the tank 2 and the piping 10 where liquefied carbon dioxide exists. In this embodiment, the temperature sensor 30 includes, for example, a first temperature sensor 30A to a fifth temperature sensor 30E.

As shown in FIG. 6, the first temperature sensor 30A, the second temperature sensor 30B, and the third temperature sensor 30C detect the temperature of the liquefied carbon dioxide stored liquid L at each part of the tank 2. The first temperature sensor 30A detects the temperature of the upper part of the tank 2. The second temperature sensor 30B detects the temperature at the bottom inside the tank 2. The third temperature sensor 30C detects the temperature of the middle part above the bottom part of the tank 2. For example, a thermal camera or the like can be used as the first temperature sensor 30A and the second temperature sensor 30B. For example, a thermocouple or the like can be used as the third temperature sensor 30C.
The number and arrangement of temperature sensors 30 provided in the tank 2 are not limited in any way, and other temperature sensors 30 may be provided in addition to the first temperature sensor 30A, second temperature sensor 30B, and third temperature sensor 30C. good. Moreover, some of the first temperature sensor 30A, the second temperature sensor 30B, and the third temperature sensor 30C may be omitted.

As shown in FIG. 2, the fourth temperature sensor 30D and the fifth temperature sensor 30E detect the temperature of each part within the pipe 10. The fourth temperature sensor 30D and the fifth temperature sensor 30E are provided in each of the loading pipe 11 and the discharging pipe 12. The fourth temperature sensor 30D detects the pressure near the pipe wall of the pipe 10. The fifth temperature sensor 30E detects the temperature of an intermediate portion within the pipe 10 that is away from the pipe wall. For example, a thermal camera or the like can be used as the fourth temperature sensor 30D. As the fifth temperature sensor 30E, for example, a thermocouple or the like can be used.
The number and arrangement of temperature sensors provided in the pipe 10 are not limited at all, and other temperature sensors 30 may be provided in addition to the fourth temperature sensor 30D and the fifth temperature sensor 30E. Further, a plurality of sets of the fourth temperature sensor 30D and the fifth temperature sensor 30E may be provided at intervals in the extending direction of the pipe 10.

(Solid detection unit configuration)
FIG. 7 is a diagram showing a solid state detection unit according to the second embodiment of the present disclosure.
As shown in FIG. 7, the solid detection unit 50B detects the solid B mixed in the stored liquid L of liquefied carbon dioxide in the region in the piping 10 where liquefied carbon dioxide exists from the outside of the piping 10. As the solid detection unit 50B, for example, a laser detection sensor, a microwave detection sensor, a capacitance type sensor, etc. can be used. For example, when a microwave detection sensor is used as the solid state detection section 50B, the solid state detection section 50B includes a pair of microwave horns 51A, 51B and a microwave generator 52, as shown in FIG. The pair of microwave horns 51A and 51B are opposed to each other with the piping 10 in between.

The microwave generator 52 generates microwaves using a pair of microwave horns 51A and 51B. The solid detection unit 50B detects particulate solids B mixed in the liquefied carbon dioxide stored liquid L in the pipe 10 based on changes in the generated microwaves. The solid detection unit 50B detects, as a solid B, a granular body in which liquefied carbon dioxide is solidified and a granular body in which impurities contained in the liquefied carbon dioxide are solidified in the stored liquid L of liquefied carbon dioxide. Note that the solid detection unit 50B may detect the solid B mixed in the stored liquid L of liquefied carbon dioxide in the area where the liquefied carbon dioxide exists in the tank 2 from outside the tank 2.

(Hardware configuration diagram)
FIG. 3 is a diagram showing a hardware configuration of a control device according to an embodiment of the present disclosure.
As shown in FIG. 3, the control device 60B includes a CPU 61 (Central Processing Unit), a ROM 62 (Read Only Memory), a RAM 63 (Random Access Memory), a storage 64 such as an HDD (Hard Disk Drive), and a signal. Includes a transmitting/receiving module 65 It's a computer.

(Functional block diagram)
FIG. 4 is a functional block diagram of a control device according to an embodiment of the present disclosure.
As shown in FIG. 4, the CPU 61 of the control device 60B controls each of the signal input section 70, storage section 71, estimation section 72B, control section 73B, and output section 75 by executing a program stored in advance in the storage 64 or the like. Realize functional configuration.

The signal input unit 70 receives detection signals from the pressure sensor 20 and the temperature sensor 30 via the signal transmission/reception module 65.

The storage unit 71 stores triple point information based on the composition of the liquefied carbon dioxide storage liquid L stored in the tank 2. The stored liquid L of liquefied carbon dioxide contains liquefied carbon dioxide and impurities mixed in the liquefied carbon dioxide. The pressure and temperature at the triple point of such stored liquid L are different from those of liquefied carbon dioxide containing no impurities. Further, the pressure and temperature at the triple point differ depending on the amount of impurities relative to the liquefied carbon dioxide in the stored liquid L. For this reason, before storing the liquefied carbon dioxide storage liquid L in the tank 2, analyze the composition of the storage liquid L and obtain information on the triple point of the storage liquid L, including the pressure and temperature at the triple point. . The acquired triple point information is stored in the storage unit 71.

The estimation unit 72B determines the state of dry ice production in the region where liquefied carbon dioxide exists based on the detection results of the pressure sensor 20 and the temperature sensor 30 and the presence or absence of detection of solid B in the detection result of the solid detection unit 50B. Estimate.
The estimation unit 72B determines whether or not the inside of the tank 2 and the pipe 10 are liquefied by the pressure sensors 20 (first pressure sensor 20A to fifth pressure sensor 20E) based on the detection signal from the pressure sensor 20 received by the signal input unit 70. A detection result of the pressure of the stored liquid L in a region where carbon dioxide exists is obtained. The estimating unit 72B estimates the temperature at each part in the tank 2 and the piping 10 by the temperature sensors 30 (first temperature sensor 30A to fifth temperature sensor 30E) based on the detection signal from the temperature sensor 30 received by the signal input unit 70. , obtain the detection result of the temperature of the stored liquid L in the region where liquefied carbon dioxide exists.

The estimation unit 72B estimates the state of dry ice production based on the detection results of the pressure sensor 20 and the temperature sensor 30 and the triple point information stored in the storage unit 71. The estimation unit 72B calculates the value of the stored liquid L based on the obtained pressure and temperature of the stored liquid L in the region where liquefied carbon dioxide exists and the triple point information of the stored liquid L stored in the storage unit 71. Compare the pressure and temperature at the triple point. The estimation unit 72B calculates that the pressure of the stored liquid L in the region where liquefied carbon dioxide exists is lower than the pressure at the triple point of the stored liquid L, and the temperature of the stored liquid L in the region where liquefied carbon dioxide exists is lower than the pressure of the stored liquid L in the region where liquefied carbon dioxide exists. It is estimated that when the temperature is higher than the triple point temperature of the liquid L, dry ice is generated in the stored liquid L in a region where liquefied carbon dioxide exists.

Furthermore, when the solid detection unit 50B detects the solid B in the stored liquid L of liquefied carbon dioxide, the estimation unit 72B determines that the liquefied carbon dioxide or the impurities contained in the liquefied carbon dioxide have solidified (solidified). We estimate that.
In this embodiment, the estimating unit 72B estimates that dry ice is generated in the stored liquid L based on the pressure and temperature detection results in the area where liquefied carbon dioxide exists, and When solid B is detected in the stored liquid L, it is assumed that dry ice is generated in the region where liquefied carbon dioxide exists.

The control unit 73B controls the operation of the pump 13 and the on-off valves 15 and 16 in order to suppress the generation of dry ice based on the dry ice generation status estimated by the estimation unit 72B.
When the estimator 72B estimates that dry ice is generated, the controller 73B stops the operation of the pump 13, for example, to suppress the pressure drop in the tank 2. In addition, when the estimating unit 72B estimates that dry ice is generated, the control unit 73B increases the rotational speed of the pump 13 to reduce the amount of liquid L (liquefied carbon dioxide) stored in the pipe 10. It is also possible to apply pressure.
Further, the control unit 73B may close the on-off valves 15 and 16 to recover the static pressure in the pipe 10 when the estimation unit 72B estimates that dry ice is generated.
The control unit 73B may control all or only some of the operations of the pump 13 and the on-off valves 15 and 16. Further, the control unit 73B may control the operations of the pump 13 and the on-off valves 15 and 16 at the same time or at different timings. In addition to the above, the control unit 73A may supply pressurized fluid to a region where liquefied carbon dioxide exists.

(Steps for estimating dry ice production status)
FIG. 8 is a flowchart illustrating the procedure of a method for estimating the production status of dry ice according to an embodiment of the present disclosure.
As shown in FIG. 8, the method S20 for estimating the production status of dry ice according to the embodiment of the present disclosure includes a step S21 of detecting pressure and temperature, a step S22 of detecting the presence or absence of solids, and a step S22 of detecting the presence or absence of solids. The process includes step S23 of estimating the production status, step S24 of determining whether the situation is such that dry ice is produced, and step S25 of controlling the operation of the pump and the on-off valve.

In step S21 of detecting the pressure and temperature, the pressure sensor 20 and the temperature sensor 30 detect the pressure and temperature of the region in the tank 2 and the pipe 10 where liquefied carbon dioxide exists. For this purpose, the first pressure sensor 20A, the second pressure sensor 20B, and the third pressure sensor 20C detect the pressure of each part within the tank 2. Further, a fourth pressure sensor 20D and a fifth pressure sensor 20E detect the pressure of each part within the pipe 10. Further, a first temperature sensor 30A, a second temperature sensor 30B, and a third temperature sensor 30C detect the temperature of each part within the tank 2. Further, a fourth temperature sensor 30D and a fifth temperature sensor 30E detect the temperature of each part within the pipe 10.
Detection signals indicating the detection results of the pressure sensor 20 and temperature sensor 30 are transmitted to the control device 60B.

In step S22 of detecting the presence or absence of a solid, the solid detection unit 50B detects, from the outside of the pipe 10, the solid B mixed in the liquefied carbon dioxide storage liquid L in the region in the pipe 10 where the liquefied carbon dioxide exists. Detect presence or absence. A detection signal indicating the detection result in the solid state detection section 50B is transmitted to the control device 60B.

In step S23 of estimating the production status of dry ice, the production status of dry ice in the region where liquefied carbon dioxide exists is estimated based on the pressure and temperature detection results in step S21 and the detection result of solid B in step S22. Estimate.
For this purpose, the signal input section 70 of the control device 60B receives detection signals from the pressure sensor 20, the temperature sensor 30, and the solid state detection section 50B. The estimating unit 72B then estimates the inside of the tank 2 and the inside of the piping 10 by the pressure sensors 20 (first pressure sensor 20A to fifth pressure sensor 20E) based on the detection signal from the pressure sensor 20 received by the signal input unit 70. The detection results of the pressure of the stored liquid L in each part are acquired. Furthermore, the estimating unit 72B determines the temperature inside the tank 2 and inside the piping 10 by the temperature sensors 30 (first temperature sensor 30A to fifth temperature sensor 30E) based on the detection signal from the temperature sensor 30 received by the signal input unit 70. The detection results of the temperature of the stored liquid L in each part are acquired. Furthermore, the estimation unit 72B acquires information on the triple point of the stored liquid L stored in the storage unit 71.

In step S23 of estimating the production status of dry ice, the estimating unit 72B further estimates whether the dry ice is Estimate the generation status of. This is based on the pressure and temperature of the stored liquid L in the region where liquefied carbon dioxide is present, acquired by the estimating unit 72B, and information on the triple point of the stored liquid L stored in the storage unit 71. Compare the pressure and temperature at the triple point of L. Here, the estimation unit 72B calculates that the pressure of the stored liquid L in the region where liquefied carbon dioxide exists is lower than the pressure at the triple point of the stored liquid L, and the temperature of the stored liquid L in the region where liquefied carbon dioxide exists. is higher than the temperature of the triple point of the stored liquid L, it is estimated that dry ice is generated in the stored liquid L in a region where liquefied carbon dioxide exists.

The estimation unit 72B obtains a detection result indicating the presence or absence of the solid B mixed in the stored liquid L based on the detection signal from the solid detection unit 50B received by the signal input unit 70. The estimation unit 72B calculates that when the solid detection unit 50B detects the presence of the solid B in the stored liquid L of liquefied carbon dioxide, the liquefied carbon dioxide or the impurities contained in the liquefied carbon dioxide solidify, and the stored liquid L It is assumed that this is a situation where dry ice is generated inside.
In the present embodiment, the estimating unit 72B estimates that dry ice is generated in the stored liquid L based on the pressure and temperature detection results of the region where liquefied carbon dioxide exists, and When solid B is detected in the stored liquid L, it is assumed that dry ice is generated in the region where liquefied carbon dioxide exists.

In step S24 of determining whether the situation is such that dry ice is generated, it is determined whether the situation is such that dry ice is generated in the stored liquid L in the region where liquefied carbon dioxide exists in step S23.
As a result of this determination, if it is determined that dry ice is not generated in the stored liquid L in the region where liquefied carbon dioxide exists (No in step S24), the process returns to step S21.
On the other hand, if it is determined that dry ice is generated in the stored liquid L in the region where liquefied carbon dioxide exists (Yes in step S24), the process proceeds to step S25.

In step S25 of controlling the operation of the pump and the on-off valve, if it is determined in step S24 that the situation is such that dry ice is generated in the stored liquid L, the control unit 73B controls the operation of the pump 13 and the on-off valve 15, 16 operations. For example, the control unit 73B stops the operation of the pump 13 to suppress the pressure drop in the tank 2. Further, the control unit 73B may increase the rotation speed of the pump 13 to pressurize the stored liquid L (liquefied carbon dioxide) in the pipe 10. Further, the control unit 73B closes the on-off valves 15 and 16 to recover the static pressure within the pipe 10. This aims to suppress the growth of dry ice and eliminate the generated dry ice.

(effect)
In the liquefied carbon dioxide equipment 1B of the above embodiment, the pressure sensor 20 and the temperature sensor 30 detect the pressure and temperature of a region where liquefied carbon dioxide exists inside at least one of the tank 2 and the piping 10. Thereby, even if the liquefied carbon dioxide contains impurities, the estimating unit 72B calculates the pressure and temperature of the region where the liquefied carbon dioxide exists based on the detection results of the pressure sensor 20 and the temperature sensor 30. However, it can be compared with the pressure and temperature at the triple point of liquefied carbon dioxide containing impurities. Thereby, it is possible to estimate with high accuracy the state of dry ice production in a region where liquefied carbon dioxide exists. Therefore, even if the liquefied carbon dioxide contains impurities, the production of dry ice can be effectively suppressed.

Furthermore, in the embodiment described above, the storage unit 71 stores triple point information based on the composition of the stored liquid L stored in the tank 2. The estimation unit 72B estimates the state of dry ice production based on the detection results of the pressure sensor 20 and the temperature sensor 30 and the triple point information stored in the storage unit 71. Thereby, the state of dry ice production in the stored liquid L, which is liquefied carbon dioxide containing impurities, can be estimated with higher accuracy.

Furthermore, in the embodiment described above, the control unit 73B controls the operation of the pump 13 based on the dry ice production status estimated by the estimation unit 72B. As a result, when the estimator 72B estimates that dry ice is generated, the operation of the pump 13 is controlled to perform processes such as suppressing the generation of dry ice and eliminating the generated dry ice. can do. Examples of controlling the operation of the pump 13 include stopping the operation of the pump 13 and pressurizing liquid carbon dioxide by the pump 13.

Furthermore, in the embodiment described above, when the estimation unit 72B estimates that the situation is such that dry ice is generated, the on-off valves 15 and 16 are closed, thereby suppressing the generation of dry ice.

Further, in the embodiment described above, the solid detection unit 50B detects the solid B mixed in the stored liquid L of liquefied carbon dioxide in the region where liquefied carbon dioxide exists. When solid B is detected in the liquefied carbon dioxide stored liquid L, it can be assumed that the liquefied carbon dioxide or the impurities contained in the liquefied carbon dioxide have solidified. The estimation unit 72B more effectively estimates the state of dry ice production in the region where liquefied carbon dioxide exists, based on the pressure and temperature of the region where liquefied carbon dioxide exists, and whether solid B is detected. be able to.

Further, in the above embodiment, when the solid detection unit 50B detects, as the solid B, a granular body in which liquefied carbon dioxide has solidified and a granular body in which impurities contained in the liquefied carbon dioxide have solidified, the estimation unit 72B It is possible to more effectively estimate the state of dry ice production in a region where liquefied carbon dioxide exists.

In the dry ice production state estimation method S20 of the above embodiment, the dry ice production state in the region where liquefied carbon dioxide exists is estimated based on the pressure and temperature detection results in the region where liquefied carbon dioxide exists. By comparing the pressure and temperature detection results in the area where liquefied carbon dioxide exists with the pressure and temperature at the triple point of liquefied carbon dioxide containing impurities, it is possible to determine if liquefied carbon dioxide contains impurities. However, the production of dry ice can be effectively suppressed.

<Third embodiment>
Next, a third embodiment of the liquefied carbon dioxide equipment and method for estimating the production status of dry ice according to the present disclosure will be described. In the third embodiment described below, the only difference from the second embodiment is that the pressure sensor 20 and the temperature sensor 30 are omitted, so the same parts as in the second embodiment will be described with the same reference numerals. Also, duplicate explanations will be omitted.
(Overall configuration of liquefied carbon dioxide equipment)
FIG. 9 is a diagram showing a schematic configuration of a liquefied carbon dioxide facility according to a third embodiment of the present disclosure.
As shown in FIG. 9, the liquefied carbon dioxide equipment 1C in this embodiment includes at least a tank 2, a pipe 10, a solid detection section 50B, and a control device 60C.

(Functional block diagram)
FIG. 9 is a functional block diagram of a control device according to an embodiment of the present disclosure.
As shown in FIG. 9, the CPU 61 of the control device 60C controls each of the signal input section 70, storage section 71, estimation section 72C, control section 73C, and output section 75 by executing a program stored in advance in the storage 64 or the like. Realize functional configuration.

The estimation unit 72C estimates the state of dry ice production in the region where liquefied carbon dioxide exists, based on whether solid B is detected in the detection result of the solid detection unit 50B.
When the solid detection unit 50B detects the solid B in the stored liquid L of liquefied carbon dioxide, the estimation unit 72C estimates that the liquefied carbon dioxide or the impurities contained in the liquefied carbon dioxide have solidified.

Like the control unit 73B in the second embodiment, the control unit 73C controls the operation of the pump 13 and the on-off valves 15 and 16 based on the dry ice production status estimated by the estimation unit 72C.

(Steps for estimating dry ice production status)
FIG. 11 is a flowchart illustrating the procedure of a method for estimating the production status of dry ice according to an embodiment of the present disclosure.
As shown in FIG. 11, the method S30 for estimating the production status of dry ice according to the embodiment of the present disclosure includes a step S32 of detecting the presence or absence of a solid, a step S33 of estimating the production status of dry ice, and a step S33 of estimating the production status of dry ice. The process includes step S34 of determining whether or not the situation is one in which a is generated, and step S35 of controlling the operation of the pump and the on-off valve.

In step S32 of detecting the presence or absence of a solid, the solid detection unit 50B detects, from the outside of the pipe 10, the solid B mixed in the liquefied carbon dioxide stored liquid L in the area in the pipe 10 where the liquefied carbon dioxide exists. Detect presence or absence. A detection signal indicating the detection result in the solid state detection section 50B is transmitted to the control device 60C.

In step S33 of estimating the state of production of dry ice, the state of production of dry ice in the region where liquefied carbon dioxide exists is estimated based on the detection result of solid B in step S32.
For this purpose, the estimation unit 72C obtains a detection result indicating the presence or absence of the solid B mixed in the stored liquid L based on the detection signal from the solid detection unit 50B received by the signal input unit 70. The estimation unit 72C calculates that when the solid detection unit 50B detects the presence of the solid B in the stored liquid L of liquefied carbon dioxide, the liquefied carbon dioxide or impurities contained in the liquefied carbon dioxide solidify, and the stored liquid L It is estimated that this is a situation in which dry ice is generated.

In step S34 of determining whether the situation is such that dry ice is generated, it is determined in step S33 whether the situation is such that dry ice is generated in the stored liquid L in the region where liquefied carbon dioxide exists.
As a result of this determination, if it is determined that dry ice is not generated in the stored liquid L in the region where liquefied carbon dioxide exists (No in step S34), the process returns to step S31.
On the other hand, if it is determined that dry ice is generated in the stored liquid L in the area where liquefied carbon dioxide exists (Yes in step S34), the process proceeds to step S35.

In step S35 for controlling the operation of the pump and the on-off valve, if it is determined in step S34 that the situation is such that dry ice is generated in the stored liquid L, the control unit 73C controls the operation of the pump 13 and the on-off valve 15. , 16. For example, the control unit 73C stops the operation of the pump 13 to suppress the pressure drop in the tank 2. Further, the control unit 73C may increase the rotation speed of the pump 13 to pressurize the stored liquid L (liquefied carbon dioxide) in the pipe 10. Further, the control unit 73C closes the on-off valves 15 and 16 to restore the static pressure inside the pipe 10. This aims to suppress the growth of dry ice and eliminate the generated dry ice.

(effect)
In the liquefied carbon dioxide equipment 1C and the dry ice production status estimation method S30 of the above embodiment, similarly to the second embodiment, the solid detection unit 50B detects the presence of liquefied carbon dioxide in the storage liquid L in the region where liquefied carbon dioxide exists. Detect solid B mixed in. When solid B is detected in the liquefied carbon dioxide stored liquid L, it can be assumed that the liquefied carbon dioxide or the impurities contained in the liquefied carbon dioxide have solidified. The estimation unit 72C more effectively estimates the state of dry ice production in the region where liquefied carbon dioxide exists, based on the pressure and temperature of the region where liquefied carbon dioxide exists, and whether solid B is detected. be able to. Therefore, even if the liquefied carbon dioxide contains impurities, the production of dry ice can be effectively suppressed.

Further, in the embodiment described above, the solid detection unit 50B detects, as solid B, a granular material in which liquefied carbon dioxide has solidified and a granular material in which impurities contained in liquefied carbon dioxide have solidified. In this case, the estimation unit 72C can more effectively estimate the state of dry ice production in the region where liquefied carbon dioxide exists.

Furthermore, in the embodiment described above, the control unit 73C controls the operation of the pump 13 based on the dry ice production status estimated by the estimation unit 72C. As a result, when the estimator 72C estimates that dry ice is being generated, the operation of the pump 13 is controlled to perform processes such as suppressing the generation of dry ice and eliminating the generated dry ice. can do. Examples of controlling the operation of the pump 13 include stopping the operation of the pump 13 and pressurizing liquid carbon dioxide by the pump 13.

Furthermore, in the embodiment described above, when the estimator 72C estimates that dry ice is generated, the on-off valves 15 and 16 are closed, thereby suppressing the generation of dry ice.

(Other embodiments)
Although the embodiment of the present disclosure has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes design changes within the scope of the gist of the present disclosure. .
In the above embodiment, the configuration of the liquefied carbon dioxide equipment 1A to 1C is shown, but the configuration of each part can be changed as appropriate.
Further, in the above embodiment, the steps of the dry ice production status estimation method S10, S20, and S30 are shown, but the order of the above steps can be changed as appropriate.
Furthermore, in the above embodiment, the case has been described in which each functional configuration is realized by the control devices 60A to 60C executing a program stored in advance, but each function of the control devices 60A to 60C is realized by hardware. You may also do so.

Further, in the above embodiment, a case has been described in which the control units 73A to 73C close the on-off valves 15 and 16 when the estimation units 72A to 72C estimate that dry ice is generated. , when increasing the pressure in the piping 10 on the downstream side of the on-off valves 15 and 16, the on-off valves 15 and 16 may be controlled to open.

Furthermore, in the embodiment described above, a case has been described in which the solid detection units 50A and 50B detect the solid B mixed in the liquefied carbon dioxide stored liquid L in the pipe 10. However, what is detected by the solid detection unit is not limited to the solid B within the pipe 10. For example, the solid detection unit may detect the solid B mixed in the liquefied carbon dioxide stored liquid L in the tank 2.

<Additional notes>
The liquefied carbon dioxide equipment 1A, 1B and dry ice production status estimation method S10 described in each embodiment can be understood, for example, as follows.

(1) The liquefied carbon dioxide equipment 1A, 1B according to the first aspect includes a tank 2 capable of storing liquefied carbon dioxide, a pipe 10 connected to the tank 2 through which the liquefied carbon dioxide can flow, and the tank 2. 2, a pressure sensor 20 that detects the pressure in a region where the liquefied carbon dioxide exists inside at least one of the pipes 10; a temperature sensor 30 that detects the temperature of the region where the liquefied carbon dioxide exists; Estimating units 72A and 72B are provided that estimate the state of dry ice production in the area where the liquefied carbon dioxide exists based on the detection results of the sensor 20 and the temperature sensor 30.

In the liquefied carbon dioxide equipment 1A, 1B, a pressure sensor 20 and a temperature sensor 30 detect the pressure and temperature of a region where liquefied carbon dioxide exists inside at least one of the tank 2 and the piping 10. As a result, even if the liquefied carbon dioxide contains impurities, the estimation units 72A and 72B can estimate the pressure in the area where the liquefied carbon dioxide exists based on the detection results of the pressure sensor 20 and the temperature sensor 30. and temperature can be compared with the pressure and temperature at the triple point of liquefied carbon dioxide containing impurities. This makes it possible to estimate with high accuracy the state of dry ice production in the region where liquefied carbon dioxide exists. Therefore, even if the liquefied carbon dioxide contains impurities, the production of dry ice can be effectively suppressed.

(2) The liquefied carbon dioxide equipment 1B according to the second aspect is the liquefied carbon dioxide equipment 1B of (1), in which the liquefied carbon dioxide exists from the outside of at least one of the tank 2 and the piping 10. The estimation unit 72B further includes a solid detection unit 50B that detects solid B mixed in the liquefied carbon dioxide in a region where the The production status of dry ice is estimated based on the detection results.

In such a configuration, the solid detection unit 50B detects the solid B mixed in the liquefied carbon dioxide in the region where the liquefied carbon dioxide exists. When solid B is detected in liquefied carbon dioxide, it can be assumed that liquefied carbon dioxide or impurities contained in liquefied carbon dioxide have solidified. The estimation unit 72B more effectively estimates the state of dry ice production in the region where liquefied carbon dioxide exists based on the pressure and temperature of the region where liquefied carbon dioxide exists and whether solid B is detected. Can be done.

(3) The liquefied carbon dioxide equipment 1B according to the third aspect is the liquefied carbon dioxide equipment 1B of (2), in which the solid detection unit 50B detects that the liquefied carbon dioxide has solidified in the liquefied carbon dioxide. A granular material and a granular material in which impurities contained in the liquefied carbon dioxide are solidified are detected as the solid B.

As a result, when the solid detection unit 50B detects a granular body in which liquefied carbon dioxide has solidified and a granular body in which impurities contained in the liquefied carbon dioxide have solidified as solid B, the estimation unit 72B determines that liquefied carbon dioxide The production status of dry ice in the area where it exists can be estimated more effectively.

(4) The liquefied carbon dioxide equipment 1A, 1B according to the fourth aspect is the liquefied carbon dioxide equipment 1A, 1B according to any one of (1) to (3), in which liquefied carbon dioxide is stored in the tank 2. The estimation units 72A and 72B further include a storage unit 71 that stores triple point information based on the composition of the stored liquid L containing carbon and impurities mixed in the liquefied carbon dioxide. Based on the detection result of the temperature sensor 30 and the triple point information stored in the storage section 71, the dry ice production status is estimated.

In such a configuration, the storage unit 71 stores triple point information based on the composition of the stored liquid L stored in the tank 2. Estimating units 72A and 72B estimate the state of dry ice production based on the detection results of pressure sensor 20 and temperature sensor 30 and triple point information stored in storage unit 71. Thereby, the state of dry ice production in the stored liquid L, which is liquefied carbon dioxide containing impurities, can be estimated with higher accuracy.

(5) The liquefied carbon dioxide equipment 1A, 1B according to the fifth aspect is the liquefied carbon dioxide equipment 1A, 1B according to any one of (1) to (4), and is estimated by the estimation unit 72A, 72B. The apparatus further includes control units 73A and 73B that control the operation of the pump 13 provided in the tank based on the production status of the dry ice.

Thereby, the control units 73A and 73B control the operation of the pump 13 based on the dry ice production status estimated by the estimation units 72A and 72B. As a result, when the estimating units 72A and 72B estimate that dry ice will be generated, the operation of the pump 13 is controlled to suppress the generation of dry ice and eliminate the generated dry ice. can be carried out. Examples of controlling the operation of the pump 13 include stopping the operation of the pump 13 and pressurizing liquid carbon dioxide by the pump 13.

(6) The liquefied carbon dioxide equipment 1A, 1B according to the sixth aspect is the liquefied carbon dioxide equipment 1A, 1B according to any one of (1) to (5), and includes an on-off valve 15 that opens and closes the pipe 10. , 16, and the control units 73A and 73B close the on-off valves 15 and 16 when the estimating units 72A and 72B estimate that the situation is such that dry ice is generated.

Thereby, when the estimating units 72A and 72B estimate that dry ice will be generated, the on-off valves 15 and 16 are closed, thereby suppressing the generation of dry ice.

(7) The liquefied carbon dioxide equipment 1B, 1C according to the seventh aspect includes a tank 2 capable of storing liquefied carbon dioxide, a pipe 10 connected to the tank 2 through which the liquefied carbon dioxide can flow, and the tank 2. 2, and a solid detection unit 50B that detects the solid B mixed in the liquefied carbon dioxide in a region where the liquefied carbon dioxide exists inside at least one of the pipes 10, and the solid B in the solid detection unit 50B. estimating units 72B and 72C that estimate the production status of dry ice in the area where the liquefied carbon dioxide exists based on the detection status of the liquefied carbon dioxide.

Thereby, the solid detection unit 50B detects the solid B mixed in the liquefied carbon dioxide in the area where the liquefied carbon dioxide exists. The estimating units 72B and 72C estimate the state of dry ice production in the region where liquefied carbon dioxide exists, based on whether solid B is detected. Thereby, when solid B is detected in liquefied carbon dioxide, it can be estimated that liquefied carbon dioxide or impurities contained in liquefied carbon dioxide have solidified. Therefore, even if the liquefied carbon dioxide contains impurities, the production of dry ice can be effectively suppressed.

(8) The liquefied carbon dioxide equipment 1B, 1C according to the eighth aspect is the liquefied carbon dioxide equipment 1B, 1C of (7), in which the solid detection unit 50B detects the liquefied carbon dioxide in the liquefied carbon dioxide. Particulate matter in which carbon and impurities contained in the liquefied carbon dioxide are solidified is detected as the solid B.

As a result, when the solid detection unit 50B detects a granular body in which liquefied carbon dioxide has solidified and a granular body in which impurities contained in the liquefied carbon dioxide have solidified as solid B, the estimation unit 72A determines that liquefied carbon dioxide It can be estimated that dry ice may be generated in the area where it exists.

(9) The liquefied carbon dioxide equipment 1B, 1C according to the ninth aspect is the liquefied carbon dioxide equipment 1A of (7) or (8), and is based on the detection status of the solid B in the solid detection unit 50B. , further includes control units 73B and 73C that control the operation of the pump 13 provided in the tank.

Thereby, the control units 73B and 73C control the operation of the pump 13 based on the dry ice production status estimated by the estimation units 72B and 72C. As a result, when the estimating units 72B and 72C estimate that dry ice will be generated, the operation of the pump 13 is controlled to suppress the generation of dry ice and eliminate the generated dry ice. can be carried out. Examples of controlling the operation of the pump 13 include stopping the operation of the pump 13 and pressurizing liquid carbon dioxide by the pump 13.

(10) The liquefied carbon dioxide equipment 1B, 1C according to the tenth aspect is the liquefied carbon dioxide equipment 1B, 1C according to (9), and includes on-off valves 15, 16 for opening and closing the pipe 10, and the control unit When the solid B is detected by the estimating units 72B and 72C, the estimators 73B and 73C infer that the situation is such that dry ice is generated, and close the on-off valves 15 and 16.

Thereby, when the estimating units 72B and 72C estimate that dry ice will be generated, the on-off valves 15 and 16 are closed, thereby suppressing the generation of dry ice.

(11) Dry ice production status estimation methods S10 and S20 according to the eleventh aspect include dry ice production status estimation methods S10 and 1B in any one of the liquefied carbon dioxide facilities 1A and 1B of (1) to (6), S20, steps S11 and S21 of detecting the pressure and temperature in the region where the liquefied carbon dioxide exists, and dry ice in the region where the liquefied carbon dioxide exists based on the detection results of the pressure and the temperature. Steps S12 and S23 of estimating the generation status of.

These methods S10 and S20 for estimating the production status of dry ice estimate the production status of dry ice in the area where liquefied carbon dioxide exists based on the pressure and temperature detection results in the area where liquefied carbon dioxide exists. can. By comparing the pressure and temperature detection results in the area where liquefied carbon dioxide exists with the pressure and temperature at the triple point of liquefied carbon dioxide containing impurities, it is possible to determine if liquefied carbon dioxide contains impurities. However, the production of dry ice can be effectively suppressed.

(12) Dry ice production status estimation methods S20 and S30 according to the twelfth aspect include dry ice production status estimation methods S20 and 1C in any one of the liquefied carbon dioxide facilities 1B and 1C of (7) to (10), S30, steps S22 and S32 of detecting the presence or absence of solid B mixed in the liquefied carbon dioxide in the area where the liquefied carbon dioxide exists; and based on the detection result of the solid B, the liquefied The method includes steps S23 and S33 for estimating the production status of dry ice in a region where carbon dioxide exists.

These dry ice production status estimation methods S20 and S30 detect the presence or absence of solid B mixed in liquefied carbon dioxide in a region where liquefied carbon dioxide exists, and based on the detection result, determine whether liquefied carbon dioxide is present or not. Estimate the state of dry ice production in the area where it exists. When solid B is detected in liquefied carbon dioxide, it can be presumed that liquefied carbon dioxide or impurities contained in liquefied carbon dioxide have solidified. Therefore, even if the liquefied carbon dioxide contains impurities, the production of dry ice can be effectively suppressed.

1A to 1C...Liquefied carbon dioxide equipment 2...Tank 3...Cylindrical part 4...End plate part 10...Piping 11...Loading piping 12...Discharging piping 13...Pump 15, 16...Opening/closing valve 20...Pressure sensor 20A...First pressure Sensor 20B...Second pressure sensor 20C...Third pressure sensor 20D...Fourth pressure sensor 20E...Fifth pressure sensor 30...Temperature sensor 30A...First temperature sensor 30B...Second temperature sensor 30C...Third temperature sensor 30D...Third temperature sensor Four temperature sensors 30E...Fifth temperature sensor 50B...Solid detection unit 51A, 51B...Microwave horn 52...Microwave generator 60A-60C...Control device 61...CPU 62...ROM 63...RAM 64...Storage 65...Signal transmission/reception module 70...Signal input section 71...Storage section 72A-72C...Estimation section 73A-73C...Control section 75...Output section B...Solid Dc...Central axis direction Dv...Vertical direction L...Stored liquid S10, S20, S30...Dry ice Generation status estimation method S11, S21... Step of detecting pressure and temperature S12, S23, S33... Step of estimating the production status of dry ice S13, S24, S34... Determining whether the situation is such that dry ice is generated Steps for determining S14, S25, S35...Steps for controlling the operation of the pump and on-off valves S22, S32...Steps for detecting the presence or absence of solids

In order to solve the above problems, a liquefied carbon dioxide facility according to the present disclosure includes a tank, piping, a pressure sensor, a temperature sensor, an estimation section, and a storage section . The tank can store liquefied carbon dioxide. The piping is connected to the tank so that the liquefied carbon dioxide can flow therethrough. The pressure sensor detects a pressure in a region where the liquefied carbon dioxide exists inside at least one of the tank and the piping. The temperature sensor detects the temperature of the region where the liquefied carbon dioxide is present. The estimation unit estimates the state of dry ice production in the region where the liquefied carbon dioxide exists based on the detection results of the pressure sensor and the temperature sensor. The storage unit stores triple point information based on the composition of a stored liquid containing liquefied carbon dioxide stored in the tank and impurities mixed in the liquefied carbon dioxide. The information on the triple point is information on the pressure and temperature at the triple point depending on the amount of impurities with respect to the liquefied carbon dioxide, and the estimating section stores the detection results of the pressure sensor and the temperature sensor and the storage section. The generation status of dry ice is estimated by comparing the information on the pressure and temperature of the triple point corresponding to the amount of the impurities stored in .

Claims (12)

A tank capable of storing liquefied carbon dioxide;
piping connected to the tank and through which the liquefied carbon dioxide can flow;
a pressure sensor that detects the pressure in a region where the liquefied carbon dioxide exists inside at least one of the tank and the piping;
a temperature sensor that detects the temperature of the region where the liquefied carbon dioxide exists;
an estimation unit that estimates the state of dry ice production in the region where the liquefied carbon dioxide exists based on the detection results of the pressure sensor and the temperature sensor;
A liquefied carbon dioxide facility equipped with further comprising a solid detection unit that detects solids mixed in the liquefied carbon dioxide in a region where the liquefied carbon dioxide exists from the outside of at least one of the tank and the piping,
The liquefied carbon dioxide equipment according to claim 1, wherein the estimating unit estimates the production status of dry ice based on the detection results of the pressure sensor and the temperature sensor, and the detection results of the solid state detection unit. The solid detection unit detects, as the solid, a granular body in which the liquefied carbon dioxide is solidified and a granular body in which impurities contained in the liquefied carbon dioxide are solidified in the liquefied carbon dioxide. Liquefied carbon dioxide equipment. Further comprising a storage unit that stores triple point information based on the composition of a stored liquid containing liquefied carbon dioxide stored in the tank and impurities mixed in the liquefied carbon dioxide,
3. The estimation unit estimates the production status of dry ice based on the detection results of the pressure sensor and the temperature sensor, and information on the triple point stored in the storage unit. liquefied carbon dioxide facility. The liquefied carbon dioxide equipment according to claim 1 or 2, further comprising a control unit that controls operation of a pump provided in the tank based on the production status of the dry ice estimated by the estimation unit. comprising an on-off valve that opens and closes the piping,
The liquefied carbon dioxide equipment according to claim 5, wherein the control unit closes the on-off valve when the estimation unit estimates that the situation is such that the dry ice is generated. A tank capable of storing liquefied carbon dioxide;
piping connected to the tank and through which the liquefied carbon dioxide can flow;
a solid detection unit that detects solids mixed in the liquefied carbon dioxide in a region where the liquefied carbon dioxide exists inside at least one of the tank and the piping;
an estimating unit that estimates the state of dry ice production in the region where the liquefied carbon dioxide exists based on the state of detection of the solid by the solid state detecting unit;
A liquefied carbon dioxide facility equipped with The liquefied carbon dioxide equipment according to claim 7, wherein the solid detection unit detects, as the solid, the liquefied carbon dioxide and a particulate material in which impurities contained in the liquefied carbon dioxide are solidified in the liquefied carbon dioxide. The liquefied carbon dioxide equipment according to claim 7 or 8, further comprising a control unit that controls operation of a pump provided in the tank based on the detection status of the solid in the solid detection unit. comprising an on-off valve that opens and closes the piping,
The liquefied carbon dioxide equipment according to claim 9, wherein the control unit estimates that the dry ice is generated when the solid is detected by the estimating unit, and closes the on-off valve. A method for estimating the production status of dry ice in the liquefied carbon dioxide equipment according to claim 1 or 2, comprising:
detecting the pressure and temperature of the region where the liquefied carbon dioxide is present;
A method for estimating the production status of dry ice, including the step of estimating the production status of dry ice in the area where the liquefied carbon dioxide exists based on the detection results of the pressure and the temperature. A method for estimating the production status of dry ice in the liquefied carbon dioxide equipment according to claim 7 or 8, comprising:
Detecting the presence or absence of solids mixed in the liquefied carbon dioxide in the region where the liquefied carbon dioxide exists;
A method for estimating the production status of dry ice, including the step of estimating the production status of dry ice in the region where the liquefied carbon dioxide exists based on the detection result of the solid.

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