JP6930883B2 - Transportation method of tank with stirrer handling alkali metal dispersion - Google Patents

Description

The present invention relates to a method for transporting a tank with a stirrer that handles an alkali metal dispersion. More specifically, the present invention handles stirring with an alkali metal dispersion without causing spontaneous ignition or hydrogen gas generation due to residual alkali metal, and while preventing damage to the stirring blade, stirring shaft, etc. during transportation. Concerning how to safely transport machined tanks.

A tank with a stirrer may be transported by placing it vertically or horizontally on a transport vehicle in almost the same state without removing the stirrer.
Tanks with an inner diameter of 1000 mm or more or a capacity of 500 L or more (large tanks) usually have a manhole. It is possible to put in a can from a manhole and cure the stirring blades and baffles in the tank. However, in a large tank that handles alkali metal dispersions, when the manhole is opened, the water in the air reacts with the remaining alkali metal, causing spontaneous ignition, hydrogen gas generation, etc. It is practically impossible to do so. In addition, since large tanks are transported horizontally on trucks, the stirring shaft, stirring blades, etc. may be damaged if they are not properly cured.

Since a tank (small tank) having an inner diameter of less than 1000 mm or a capacity of less than 500 L can be placed vertically on a transport vehicle, the stirring shaft is less likely to be bent due to gravity, but the possibility of damage during transportation is not zero. However, the small tank does not have a manhole, and it is not possible to put it in a can and cure the stirring shaft and the like.

As a technique for transporting a tank with a stirrer, Patent Document 1 is characterized in that a nozzle for mounting a support is provided in the tank body of the stirrer, and the nozzle and the stirring shaft are connected by a support to fix the stirring shaft. The integrated transportation structure of the stirrer is disclosed.

Jikkenhei No. 2-150029

An object of the present invention is to provide a stirrer that handles an alkali metal dispersion liquid without causing spontaneous ignition or hydrogen gas generation due to residual alkali metal and preventing damage to the stirring shaft, stirring blade, etc. during transportation. To provide a safe way to transport tanks.

As a result of studies for achieving the above object, the present invention including the following forms has been completed.

[1] Discharge the alkali metal dispersion from the tank with a stirrer that handles the alkali metal dispersion.
Pull out the stirring shaft from the tank and
Attach a protective frame to the drawn stirring shaft,
Then, including carrying the tank on a transport vehicle,
A method for transporting a tank with a stirring blade that handles an alkali metal dispersion.

[2] The transportation method according to [1], wherein the inner diameter of the tank is 1000 mm or more.
[3] The transportation method according to [1] or 2, further comprising substituting the inside of the protective frame with an inert gas.
[4] The transportation method according to any one of [1] to [3], wherein the alkali metal is metallic sodium or metallic lithium.

According to the method of the present invention, stirring using an alkali metal dispersion liquid without causing spontaneous ignition or hydrogen gas generation due to residual alkali metal and preventing damage to the stirring shaft, stirring blade, etc. during transportation. Machined tanks can be transported safely. Furthermore, after cleaning the tank at the transportation destination, the tank can be reused for another purpose without replacing the stirrer.

It is a figure which shows an example of the procedure of transporting a tank with a stirrer which removed a stirrer motor. It is a figure which shows an example of the procedure of pulling out a stirring shaft from a tank, and attaching a protective frame. It is a figure which shows an example of the tank with a stirrer installed on a pedestal. It is a figure which shows an example of the protection frame member. It is a figure which shows the state which formed the protective frame by assembling two protective frame members shown in FIG. It is a figure which shows an example of the protection frame member. It is a figure which shows the state which formed the protective frame by assembling two protective frame members shown in FIG.

Hereinafter, the present invention will be described in detail, but the present invention is not limited to this embodiment.

The target of the transportation method of the present invention is a tank with a stirrer that handles an alkali metal dispersion (see FIG. 3). Alkali metal dispersions, such as sodium dispersions, are used for the treatment of polychlorinated biphenyls (PCBs) and the like. The inner diameter of the tank 1 is preferably 1000 mm or more, more preferably 1200 to 2800 mm. Examples of the alkali metal include metallic potassium, metallic sodium, metallic lithium and the like.

In the method of the present invention, first, the alkali metal dispersion liquid is discharged from the tank with a stirring blade that handles the alkali metal dispersion liquid. The discharge can be performed, for example, through a pipe at the bottom of the tank 1.

To prepare for transportation, the valve, pipe, PH meter, thermometer, pressure meter, level switch, safety valve, etc. connected to the tank 1 can be removed, and the opening on the tank side can be closed with a blind flange, bag nut, etc. ..

For transportation, the stirring motor 7 and / or the speed reducer may or may not be removed. In the form in which the speed reducer shaft end and the stirring shaft (or the intermediate shaft) are connected by a flexible coupling (for example, the capacity is 20 m ³ or more), only the speed reducer may be removed.

Next, in preparation for separating the tank from the pedestal, it is preferable to install a temporary abutment under the tank to support the tank, support the tank with a forklift, or suspend the tank with a hoist or the like. It is preferable to calculate the weight of the tank in advance from drawings and the like, and prepare nylon slings, hanging tools, ropes, etc. having sufficient strength. A nylon sling or the like may be wrapped around the tank. When using a wire rope, it is preferable to protect the part that hits the tank body with rubber or cloth.

Then, the tank 1 is separated from the pedestal 4. The tank 1 separated from the pedestal 4 can be gently lifted by using a forklift, a hoist, a tow truck, or the like. The tank 1 can be gradually tilted to a horizontal state and placed horizontally on a pallet or the like. The tank 1 may be placed vertically on a pallet or the like in a vertical state.

Then, the stirring shaft 2 is pulled out from the tank. The stirring shaft 2 may be pulled out from the tank in the vertical position or may be pulled out from the tank in the horizontal state. Alkali metal may be attached to the drawn stirring shaft 2. When the attached alkali metal comes into contact with water in the air, it ignites or hydrogen gas is generated. Therefore, the protective frame 3 is attached to the drawn stirring shaft 2. The protective frame 3 preferably has a shape corresponding to the shape of the mounting portion. For example, the protective frame 3 is a ring formed by an inner arch formed by assembling a protective frame member (FIG. 4) having a double arch shape. A protective frame (Fig. 5) that covers the stirring shaft portion, a protective frame (Fig. 7) that covers the joint portion between the stirring shaft and the stirring motor shaft formed by assembling a single arch-shaped protective frame member (Fig. 6), etc. Be prepared. The protective frames shown in FIGS. 4 to 7 are designed so that they can be assembled by flanges. The protective frame preferably has a structure that prevents the alkali metal adhering to the stirring shaft from coming into contact with water in the air when attached. The protective frame is preferably made of a material that does not react with the alkali metal. Examples of the material include steel and stainless steel. Alternatively, it may be coated with a material that does not react with the alkali metal. Examples of the coating material include titanium. After attaching the protective frame 3, it is preferable to introduce an inert gas such as dry nitrogen gas into the space inside the protective frame via the gas line 8 and replace the inside of the protective frame with the inert gas.

After the protective frame 3 is attached to the stirring shaft 2, the tank may be packed with ropes, sheets, and cushioning materials. Then, the tank is placed horizontally or vertically on the loading platform of the transport vehicle, fixed, and transported to the target location (see FIG. 1). During transportation, the inert gas may continue to be introduced into the tank 1 via the gas line 8.

When the tank is delivered to the destination, unload the tank from the loading platform of the transport vehicle. It is preferable to visually inspect the appearance. For example, inspect whether there are any abnormalities such as improper packaging, evidence of tank movement during transportation, scratches on the painted surface, or abnormalities in the stirring shaft. Next, the protective frame 3 is removed, and the stirring shaft 2 is pushed into the tank. After that, the tank can be placed vertically and installed on the pedestal of the destination.

For centering of the tank with agitator, for example, the inclination of the tank is checked by using a plumb bob at two circumferences (in the perpendicular direction). Adjust so that the inclination is preferably 1 mm / m or less. The centering of the tank in which the speed reducer is separated and transported is adjusted so that the inclination of the can body is preferably 1 mm / m or less, with the upper surface of the speed reducer stand as a reference surface, for example.

After installing in place and centering, it is preferable to check for looseness of bolts, nuts or clamps during transportation. The packaging can be unpacked and valves, intubations, pH meters, thermometers, level switches, safety valves, etc. can be attached to each opening of the tank.

In the above method, the protective frame 3 suppresses vibration of the stirring shaft, stirring blade, etc. during transportation, and prevents damage to them.

1: Tank 2: Stirring shaft 3: Protective frame 4: Pedestal 5: Deceleration mechanism 6: Stirring blade 7: Stirring motor 8: Gas line

Claims (4)

Discharge the alkali metal dispersion from the tank with a stirrer that handles the alkali metal dispersion.
Pull out the stirring shaft from the tank and
A protective frame having a structure for preventing the alkali metal adhering to the stirring shaft from coming into contact with water in the air and preventing damage to the stirring shaft is attached to the drawn stirring shaft.
Then, including carrying the tank on a transport vehicle,
A method for transporting a tank with a stirring blade that handles an alkali metal dispersion. The transportation method according to claim 1, wherein the inner diameter of the tank is 1000 mm or more. The transportation method according to claim 1 or 2, further comprising substituting the inside of the protective frame with an inert gas. The transportation method according to any one of claims 1 to 3, wherein the alkali metal is metallic sodium or metallic lithium.

Images