The present invention relates to a tank container and a method of manufacturing the same.
Tank containers have hitherto been widely used for transporting liquid, powder, or gas such as high-pressure gas. In particular, an ISO tank container is a container that conforms to the standards defined by ISO, and hence the ISO tank container is suitable for overseas transportation as well as domestic transportation by a trailer, a container ship, or the like.
The contents to be transported by the tank container cover a wide variety of things ranging from chemicals, hazardous materials, raw materials for pharmaceuticals to foodstuffs, in addition to the above-mentioned classification by form such as liquid, powder, or gas. Of those, lithium hexafluorophosphate is a raw material for an electrolyte of a lithium/lithium ion secondary battery, and there is an increasing need for exporting lithium hexafluorophosphate overseas, as well as the need for lithium hexafluorophosphate in Japan.
Lithium hexafluorophosphate is white crystalline powder and is rapidly hydrolyzed to generate hydrogen fluoride that is extremely toxic and highly corrosive, when being brought into contact with moisture in the air, as represented by the following chemical formula.
LiPF6+4H2O→LiF (lithium fluoride)+5HF (hydrogen fluoride)+H3PO4 (phosphoric acid)
In addition, lithium hexafluorophosphate has a risk in that, when lithium hexafluorophosphate is brought into contact with moisture in the air, a metal of an accommodation container may be corroded due to the generation of acid to cause contamination, resulting in deterioration of quality.
In addition, lithium hexafluorophosphate has low thermal stability and undergoes thermal decomposition at a relatively low temperature of about 60° C.
Accordingly, in order to accommodate and transport lithium hexafluorophosphate (powder), the airtightness that does not allow lithium hexafluorophosphate to be brought into contact with moisture in the air and the temperature stability that maintains the temperature equal to or lower than a certain temperature are required. In addition, in terms of quality, lithium hexafluorophosphate (powder) is required to be transported under the condition that a high-purity state is maintained without the risk of being mixed with other impurities during accommodation, transportation, and the like.
In general, as a transport container for powder, there are those employing the following dump system, pressurization system, and blow system.
1) Dump System
The dump system is a system in which powder is accommodated in a transport container such as a square container and an end portion of the transport container on an opposite side of a discharge port is lifted to incline the transport container, to thereby discharge the powder under gravity. The dump system has an advantage in that the capacity of the transport container for accommodating the powder can be increased as in a rectangular container. In addition, when the transport container is inclined at an angle equal to or larger than an angle of repose of the powder, the powder can be discharged, and stable discharge is possible. Meanwhile, in the dump system, the discharge port of the transport container is exposed to the atmosphere, and hence it is difficult to maintain airtightness.
2) Pressurization System (Pressure-Resistant Container)
The pressurization system is a system in which gas is introduced into a pressure-resistant container without inclining the container itself accommodating powder and the powder is discharged under a state in which the powder is blown up to decrease density. In this pressurization system, the pressurization and discharge are not performed once, but the pressurization and discharge are repeated a plurality of times in many cases. The pressurization system is used for powder having a low true density in many cases, and it is difficult to apply the pressurization system to powder having a high density, such as lithium hexafluorophosphate (powder).
3) Blow System
The blow system is a system in which, in order to further blow up powder to decrease density as compared to the pressurization system, a rectangular flow path for passing gas is formed in a bottom portion along a longitudinal direction of a horizontal container, the upper surface of the flow path is upholstered with a cloth (canvas) that allows the passage of the gas, and the powder in the container is blown up and discharged through this cloth. A plurality of discharge ports may be formed in the blow system without being limited to one discharge port, and piping is directed upward so as not to be closed. In the blow system, the canvas is made of an organic material, such as synthetic fibers, and there is also a risk of mixing of impurities due to, for example, the detachment of components used for fixing the canvas. The blow system has poor airtightness, and the amount of the powder that remains without being discharged is large.
Further, as a technology related to the tank container capable of transporting powder, for example, the technology disclosed in Patent Literature 1 and the like have already been proposed.
In Patent Literature 1, there is disclosed an elongated container for transporting loose powder in which a bottom of the container includes a thin film support that extends along at least a part of a length of the container and is inclined in a longitudinal direction, a gas permeable thin film is bonded to the support, and the support is configured so as not to be supported by the container between longitudinal ends thereof and between lateral ends thereof.
[PTL 1] JP 2006-509689
An object of the present invention is to provide a tank container which can accommodate and transport powder formed of hazardous material powder or the like while avoiding the contact of the powder with moisture in the air and an temperature rise to a temperature equal to or higher than a predetermined temperature, and which can also easily discharge the powder, and a method of manufacturing the tank container.
According to the invention described in claim 1, there is provided a tank container including:
a tank main body portion formed into an airtight cylindrical shape, which is configured to accommodate powder therein, and which is closed at both ends along a longitudinal direction;
a plurality of accommodation and discharge portions, which are arranged so as to be adjacent to each other along the longitudinal direction in a lower portion of the tank main body portion, which have upper end portions each airtightly joined to an inner wall of the tank main body portion and to an adjacent portion, and which have lower end portions each formed into a downward tapered shape so as to protrude outward respectively from a plurality of openings formed on an outer peripheral surface of the tank main body portion;
a heat insulating portion formed on the outer peripheral surface of the tank main body portion; and
a container frame portion having the tank main body portion fixed thereto.
According to the invention described in claim 2, in the tank container according to claim 1, an inner peripheral surface of the tank main body portion is reinforced with a reinforcing member having an annular shape or having an annular shape including a notch in part arranged between the plurality of accommodation and discharge portions adjacent to each other along the longitudinal direction of the tank main body portion.
According to the invention described in claim 3, in the tank container according to claim 1, the plurality of accommodation and discharge portions each have an inclination angle set to be equal to or larger than an angle of repose of the powder.
According to the invention described in claim 4, in the tank container according to claim 1, one or more introduction ports each configured to introduce pressurized gas into the tank main body portion are formed along the longitudinal direction in an upper end portion of the tank main body portion.
According to the invention described in claim 5, in the tank container according to claim 1, supply ports each configured to supply the powder into the plurality of accommodation and discharge portions are formed so as to correspond respectively to the plurality of accommodation and discharge portions in an upper end portion of the tank main body portion.
According to the invention described in claim 6, in the tank container according to claim 1, injection ports each configured to inject pressurized gas onto the powder accommodated in the plurality of accommodation and discharge portions are formed respectively in the lower end portions of the plurality of accommodation and discharge portions.
According to the invention described in claim 7, in the tank container according to claim 1, the plurality of accommodation and discharge portions are each formed into a downward conical shape, and a discharge port configured to discharge the powder is opened in each of the lower end portions and is opened and closed by a discharge valve formed of a ball valve.
According to the invention described in claim 8, in the tank container according to claim 1, the plurality of accommodation and discharge portions are each formed into a conical shape by joining two respective constituent members divided into semi-conical shapes along a plane in a direction intersecting the longitudinal direction of the tank main body portion to each other inside the tank main body portion.
According to the invention described in claim 9, in the tank container according to claim 1, the tank main body portion has mounting members each formed into an annular shape fixed respectively to both end portions along the longitudinal direction, and the tank main body portion is fixed to the container frame portion through intermediation of the mounting members.
According to the invention described in claim 10, in the tank container according to claim 1, in an upper end portion of the tank main body portion, a spill box portion formed into a rectangular frame shape in plan view is formed so as to surround an outer periphery of an opening formed in the upper end portion of the tank main body portion, and an outer surface of the spill box portion is covered with a heat insulating material.
According to the invention described in claim 11, there is provided a method of manufacturing a tank container, including:
a first step of forming a cylindrical tank main body portion having at least one end portion opened;
a second step of forming two respective constituent members, which are obtained by dividing each of a plurality of accommodation and discharge portions into semi-conical shapes along a plane intersecting a longitudinal direction of the tank main body portion, the plurality of accommodation and discharge portions being arranged so as to be adjacent to each other along the longitudinal direction in a lower portion of the tank main body portion, the plurality of accommodation and discharge portions having upper end portions each airtightly joined to an inner wall of the tank main body portion and to an adjacent portion and having lower end portions each formed into a downward conical shape so as to protrude outward from openings formed on an outer peripheral surface of the tank main body portion; and
a third step of forming the plurality of accommodation and discharge portions by carrying the two respective constituent members into the tank main body portion and joining the two respective constituent members to each other inside the tank main body portion.
According to the present invention, a tank container which can accommodate and transport powder formed of hazardous material powder or the like while suppressing the contact of the powder with moisture in the air and an increase in temperature to a temperature equal to or higher than a predetermined temperature, and which can also easily discharge the powder, and a method of manufacturing the tank container can be provided.
Now, embodiments of the present invention are described with reference to the drawings.
<Overall Configuration of Tank Container>
As illustrated in
As illustrated in
The tank main body portion 4 is mounted on the container frame 3 under a state of being fixed thereto through intermediation of collar members 10 and 11, as an example of short cylindrical mounting members, joined to the both end portions along the longitudinal direction of the end plates 8 and 9 by welding or the like.
An inner peripheral surface of the tank main body portion 4 is reinforced with reinforcing members 12 and 13 each having an annular shape or having an annular shape including a notch in part arranged at equal intervals between four accommodation and discharge portions 5 adjacent to each other along the longitudinal direction of the tank main body portion 4. The tank main body portion 4 is divided into four regions along the longitudinal direction corresponding to the four accommodation and discharge portions 5. The reinforcing members 12 and 13 are respectively arranged at the boundaries of the accommodation and discharge portions 5 in the tank main body portion 4. As each of the reinforcing members 12 and 13, as illustrated in
The length of the tank main body portion 4 is set to a value corresponding to the length of the ISO container. As an example of the ISO container, for example, in the case of a 20-feet tank container 1, the length is set to 6,058 mm, the width is set to 2,438 mm, and the height is set to 2,591 mm, respectively. Accordingly, the container frame 3 is configured to have a length, a width, and a height corresponding to those numerical values. As illustrated in
As illustrated in
In addition, as illustrated in
Further, on the upper end surface of the tank main body portion 4, one or more (four in the illustrated example) introduction ports 25 for introducing pressurized gas into the tank main body portion 4 are formed along the longitudinal direction. As the pressurized gas, for example, dry (water-removed) nitrogen gas N2 is used. The four introduction ports 25 are formed so as to correspond to the four accommodation and discharge portions 5, respectively. As illustrated in
The on-off valve 28 connected to each of the introduction ports 25 formed on the upper end surface of the tank main body portion 4 is driven to be opened and closed by an actuator 34 operated by compressed air, as illustrated in
In addition, on the upper end surface of the tank main body portion 4, as illustrated in
In addition, on a lower end surface of the tank main body portion 4, as illustrated in
As illustrated in
That is, of the four accommodation and discharge portions 5, in the case of the two second and third accommodation and discharge portions 52 and 53 arranged in the center portion along the longitudinal direction of the tank main body portion 4, the members arranged on both sides along the longitudinal direction thereof are the accommodation and discharge portions 5, and 54. In contrast, in the case of the two first and fourth accommodation and discharge portions 51 and 54 arranged in the both end portions along the longitudinal direction of the tank main body portion 4, the members arranged on the respective one sides are the accommodation and discharge portions 52 and 53, but the members arranged on the respective another sides are the end plates 8 and 9 of the tank main body portion 4. Thus, the two first and fourth accommodation and discharge portions 51 and 54 each have a shape different from that of the two second and third accommodation and discharge portions 52 and 53.
More specifically, the first to fourth accommodation and discharge portions 51 to 54 are common in that essentially all the portions are each formed into a downward tapered shape. Each of the accommodation and discharge portions 51 to 54 is formed by, for example, processing a plate material, such as a stainless steel plate or the like having a thickness of about 5.3 mm into a curved shape. In the first embodiment, as illustrated in
As illustrated in
In addition, as illustrated in
Further, in each of the first and fourth accommodation and discharge portions 51 and 54, both end surfaces on an outer side along the longitudinal direction are respectively cut along inner surface shapes of the end plates 8 and 9 of the tank main body portion 4 to be formed into edges 55 and 56 each having a substantially U-shape in side view as illustrated in
In each of the first to fourth accommodation and discharge portions 51 to 54, as illustrated in
Incidentally, in the tank container 1 according to the first embodiment, at the time of manufacturing the tank container 1, instead of directly using each of the first to fourth accommodation and discharge portions 51 to 54 each formed into a conical shape as illustrated in
As described above, the two constituent members 57 and 58 forming each of the first to fourth accommodation and discharge portions 51 to 54 are different in shape of edge between the two first and fourth accommodation and discharge portions 51 and 54 and the two second and third accommodation and discharge portions 52 and 53.
Manufacturing of the tank container 1 includes: a first step of forming the cylindrical portion 7 of the tank main body portion 4 formed into a cylindrical shape; a second step of forming the constituent members 57 and 58 each having a semi-conical shape, which are obtained by dividing each of the four accommodation and discharge portions 51 to 54 into two parts along the plane intersecting the upper end surface (surface having a circular shape in plan view of the conical shape) of the accommodation and discharge portions 51 to 54 and the longitudinal direction in the tank main body portion 4, the four accommodation and discharge portions 51 to 54 being arranged so as to be adjacent to each other along the longitudinal direction in the lower portion of the tank main body portion 4, the four accommodation and discharge portions 51 to 54 having upper end portions each airtightly joined to the inner wall of the tank main body portion 4 and to an adjacent portion and having lower end portions each formed into a downward conical shape so as to protrude downward from the openings 39 formed in the tank main body portion 4; and a third step of forming each of the accommodation and discharge portions 51 to 54 by carrying the two respective constituent members 57 and 58 into the tank main body portion 4 and joining the respective constituent members 57 and 58 divided into two parts to each other inside the tank main body portion 4.
More specifically, as illustrated in
When the constituent members 57 and 58 each having a semi-conical shape divided into two parts are joined to each other by welding or the like, it is desired that a band-shaped plate material 59 be joined to a joining end of one of the constituent members 57 and 58 in advance as illustrated in
In this case, the order of forming each of the four accommodation and discharge portions 51 to 54 by carrying the two constituent members 57 and 58 into the cylindrical portion 7 and joining the two constituent members 57 and 58 to each other is as described below. First, the third accommodation and discharge portion 53 is formed, and then the second accommodation and discharge portion 52 to be adjacent to the third accommodation and discharge portion 53 is joined thereto. Further, the fourth accommodation and discharge portion 54 is joined to the resultant, and finally the first accommodation and discharge portion 51 is joined to the resultant.
The reason for first joining the third accommodation and discharge portion 53 is as described below. When an end portion of the cylindrical portion 7 on the rear side is closed with the end plate 8, a joining operation becomes easier when the joining operation is performed first from the back side near the end plate 8. When the end portion of the cylindrical portion 7 on the rear side is not closed with the end plate 8, any of the third accommodation and discharge portion 53 and the second accommodation and discharge portion 52 may be joined first.
In addition, the reason for joining the fourth and first accommodation and discharge portions 54 and 51 adjacent to the end plates 8 and 9 of the cylindrical portion 7 after the third and second accommodation and discharge portions 53 and 52 in the center portion is as described below. The fourth and first accommodation and discharge portions 54 and 51 are not the same in shape in a front-and-rear direction along the longitudinal direction of the tank main body portion 4. Thus, when the fourth and first accommodation and discharge portions 54 and 51 are joined after the third and second accommodation and discharge portions 53 and 52, the joining operation can be performed in consideration of (by adjusting) the positional relationship with the third and second accommodation and discharge portions 53 and 52 joined first and the shape.
First, before the both end portions of the cylindrical portion 7 of the tank main body portion 4 are closed with the end plates 8 and 9, the two constituent members 57 and 58 forming the third accommodation and discharge portion 53 are carried into the cylindrical portion 7 of the tank main body portion 4 having at least one end portion opened from the opened end portion of the cylindrical portion 7, and the two constituent members 57 and 58 are joined to each other to form the third accommodation and discharge portion 53.
The operation of forming the third accommodation and discharge portion 53 by joining the two constituent members 57 and 58 is performed inside the cylindrical portion 7. In this case, the lower end portion of the third accommodation and discharge portion 53 is arranged so as to protrude downward from the opening 39 formed on a lower surface of the cylindrical portion 7.
Next, of the upper end portions of the third accommodation and discharge portion 53 formed integrally, the upper end portion opposed to an inner surface of the cylindrical portion 7 of the tank main body portion 4 is joined (welded) to the inner surface of the cylindrical portion 7 of the tank main body portion 4. In this case, the reinforcing members 12 and 13 have already been formed on the inner surface of the cylindrical portion 7 of the tank main body portion 4, and hence the third accommodation and discharge portion 53 is joined so as to have an appropriate positional relationship with the reinforcing members 12 and 13.
More specifically, as illustrated in
As illustrated in
After the mounting operation of the third accommodation and discharge portion 53 is finished, the two constituent members 57 and 58 forming the second accommodation and discharge portion 52 are carried into the cylindrical portion 7 of the tank main body portion 4 from the opened end portion of the cylindrical portion 7, and the two constituent members 57 and 58 are joined to each other to form the second accommodation and discharge portion 52.
In this case, the upper end portion of the second accommodation and discharge portion 52 is airtightly joined to the upper end portion of the third accommodation and discharge portion 53 through intermediation of the partition plate 60 as illustrated in
Similarly, as illustrated in
With the above-mentioned configuration, there are provided the four accommodation and discharge portions 51 to 54, which are arranged so as to be adjacent to each other along the longitudinal direction in the lower portion of the tank main body portion 4, which have upper end portions each airtightly joined to the inner wall of the tank main body portion 4 and to an adjacent portion, and which have lower end portions each formed into a downward conical shape so as to protrude downward from the openings 3 of the tank main body portion 4. As illustrated in
As illustrated in
In addition, in the lower end portion of each of the accommodation and discharge portions 51 to 54, an injection port 70 for injecting the pressurized gas to the hazardous material powder P accommodated in the accommodation and discharge portion 5 is opened at a position forming a predetermined angle with respect to the direction intersecting the longitudinal direction of the tank main body portion 4. As illustrated in
As illustrated in
The large-diameter portion 76a increased in diameter on the front side of the tank main body portion 4 is formed in a distal end portion of the supply pipe 76. As illustrated in
As illustrated in
The outer peripheral surface of the tank main body portion 4 is covered with a heat insulating material 80 (see
In addition, as illustrated in
As illustrated in
As illustrated in
As illustrated in
The container frame 3 includes rectangular frames 101 and 102 respectively forming an end surface on the front side and an end surface on the rear side along the longitudinal direction of the tank container and beam members 103 that couple the frames on the front side and the rear side to each other.
The container frame 3 is not limited to a full frame type, and a beam type in which distal ends of frames are connected to the surface of the tank main body portion may be employed.
As illustrated in
<Operation of Tank Container>
The tank container 1 according to the first embodiment can transport the hazardous material powder P while suppressing the contact of the hazardous material powder P with moisture in the air and an increase in temperature, and can also easily discharge the hazardous material powder P.
First, in order to accommodate the hazardous material powder P inside the tank main body portion 4 of the tank container 1, as illustrated in
In this case, pressurized nitrogen gas is supplied to the supply pipes 29 and 30 through the first supply valve 31.
The tank container 1 is held under an airtight state by closing the ball valve 24 and the introduction ports 25 after the accommodation operation of the hazardous material powder P is finished. Thus, the hazardous material powder P accommodated inside the tank main body portion 4 is not brought into contact with outside air at the time of accommodation (including the time of storage) and transportation. Accordingly, even when the hazardous material powder P is made of lithium hexafluorophosphate or the like, the situation in which the powder made of lithium hexafluorophosphate or the like is brought into contact with the outside air containing moisture to be rapidly hydrolyzed to generate hydrogen fluoride that is extremely toxic and highly corrosive can reliably be prevented, as represented by the following chemical formula.
LiPF6+4H2O→LiF (lithium fluoride)+5HF (hydrogen fluoride)+H3PO4 (phosphoric acid)
In addition, in the tank container 1, an outer periphery of the tank main body portion 4 is covered with a urethane foam serving as the heat insulating material 80 (see
Next, in the tank container 1, the principle of discharging the hazardous material powder P which is a load and the operation procedure for discharging the hazardous material powder P which is a load are described.
In the tank container 1, as described above, the hazardous material powder P is accommodated in the internal space of the four accommodation and discharge portions 51 to 54 and the tank main body portion 4. The hazardous material powder P in the internal space of the four accommodation and discharge portions 51 to 54 and the tank main body portion 4 is discharged with the gravity by opening the discharge valve 62 provided in the lower end portion of each of the accommodation and discharge portions 51 to 54 because the four accommodation and discharge portions 51 to 54 are each formed into a substantially conical shape.
In order to discharge the hazardous material powder P to the outside after storing and transporting the hazardous material powder P, as illustrated in
In this case, the order of opening each of the discharge valves 62 is not particularly limited. However, for example, it is desired that each of the discharge valves 62 be opened in the order of from the fourth accommodation and discharge portion 54 located on the most downstream side of the tank main body portion 4 to the third, second, and first accommodation and discharge portions 53 to 51 on the upstream side.
When the fourth discharge valve 62 of the fourth accommodation and discharge portion 54 located on the most downstream side of the tank main body portion 4 is first opened, the hazardous material powder P discharged from the fourth discharge valve 62 of the fourth accommodation and discharge portion 54 can reliably be discharged from a discharge port of the discharge pipe 65 while being assisted by the pressurized gas introduced from the third supply valve 79.
After that, when the third discharge valve 62 of the third accommodation and discharge portion 53 of the tank main body portion is opened, the hazardous material powder P discharged from the third discharge valve 62 of the third accommodation and discharge portion 53 can reliably be discharged from the discharge port of the discharge pipe 65 while being assisted by the introduced pressurized gas.
Next, when the second discharge valve 62 of the second accommodation and discharge portion 52 of the tank main body portion is opened, the hazardous material powder P discharged from the second discharge valve 62 of the second accommodation and discharge portion 52 can reliably be discharged from the discharge port of the discharge pipe 65 while being assisted by the introduced pressurized gas.
Then, when the first discharge valve 62 of the first accommodation and discharge portion 51 of the tank main body portion 4 is finally opened, the hazardous material powder P discharged from the first discharge valve 62 of the first accommodation and discharge portion 51 can reliably be discharged from the discharge port of the discharge pipe 65 while being assisted by the introduced pressurized gas.
In addition, the present invention is not limited thereto, and needless to say, the hazardous material powder P may be discharged from the discharge port of the discharge pipe 65 by simultaneously opening each of the discharge valves 62 of the first to fourth accommodation and discharge portions 51 to 54.
In any case, when the on-off valves 75 are opened under a state in which the remaining amount of the hazardous material powder P in the first to fourth accommodation and discharge portions 51 to 54 is reduced to some degree, the remaining of the hazardous material powder P in the vicinity of the bottom portions of the first to fourth accommodation and discharge portions 51 to 54 can be effectively prevented or suppressed by injecting the high-pressure nitrogen gas from the second supply pipes 73 through the filter members 72 from each of the injection ports 70 opened in the vicinity of the bottom portions of the first to fourth accommodation and discharge portions 51 to 54 as illustrated in
The tank container 1 has a structure having the above-mentioned operation mechanism, and hence can have high airtightness. The leak rate of the gas inside the tank container 1, which is a guideline of airtightness, can be recognized from a change in pressure and a change in temperature when a predetermined period of time has passed after gas (inert gas such as air, nitrogen, helium, or the like) having a constant pressure is sealed into the tank container 1.
The leak rate of the tank container 1 according to the present embodiment was determined to be 5.2×10−5 Pa·m3/sec, which is equal or less than 1.0×10−4 Pa·m3/sec that is the standard of an airtight state. Thus, the hazardous material powder P can be transported while the contact thereof with moisture in the air is suppressed, and the discharge of the hazardous material powder P can also be easily performed. As a result, mass transportation of high-value-added hazardous material powder (effective volume: 11.3 KL) becomes possible.
Number | Date | Country | Kind |
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2020-068032 | Apr 2020 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2021/014465 | 4/5/2021 | WO |