JPS592718Y2 - Liquid storage tank liquid receiving equipment - Google Patents

Description

[Detailed description of the invention] This application relates to liquid storage tank receiving equipment that allows flammable liquids to be safely received into the storage tank through vertical receiving piping without the need for complicated equipment or repairs in difficult locations. It is an idea.

Most of the flammable liquids stored in petroleum storage tanks are highly electrically insulating liquids with extremely high resistivity.
A charging phenomenon always occurs, and therefore there is a risk of a fire accident caused by static electricity.

This is because the liquid becomes electrically charged as it flows, and the larger the contact area between the liquid and the solid within a certain period of time, the greater the charge.

Furthermore, since the charging voltage is inversely proportional to the capacitance, the smaller the capacitance, the higher the voltage will appear.

For example, when the pipe is filled with liquid and is flowing down, the capacitance decreases more rapidly at the final moment when the liquid has flowed away, so a sudden rise in the charging voltage can be seen at this time. There is a real risk of ignition at times, and there are examples where static electricity is generated during the handling of flammable liquids and ignites due to the sparks created during the discharge, resulting in gas explosions or oil fires. There are many.

In this process, flammable liquid vapor is ignited by a spark generated when static electricity generated by the flow of liquid is discharged.

Considering the above points, in a large liquid storage tank, the liquid that is sent into the tank through the oil pipe is electrically charged, so the accumulation of static electricity on the liquid surface in the tank cannot be avoided, and the wave crest of the liquid surface There is a risk that the tank may be ignited due to discharge.

Therefore, the liquid receiving hole of the liquid storage tank is generally located at the lower part of the storage tank side wall A (first
Nozzle B that penetrates the bottom (see figure) or the bottom (as shown)
It is done via.

In this case, the conduit connected to the nozzle is provided horizontally, so in this case, the liquid is fed horizontally, so the flow rate can be adjusted, so the charging voltage can be relatively low, and static electricity disasters can be taken into account.

However, there are cases where this conduit C is installed vertically,
In particular, most underground storage tanks (see Figures 2 and 7) are installed vertically.

When receiving flammable liquids, it is generally necessary to control the flow rate to prevent static electricity hazards.

However, if the conduit is installed vertically, it may be very difficult to control the flow rate.

For example, when injecting liquid from the top end of a 50m long vertical pipe, if the liquid falls naturally, it will reach the bottom end at 3 Qm/s.
The speed is faster than ec.

In this state, the liquid will fall as mist or slag, but the tubes and droplets will be charged to a high potential, and the possibility of spark discharge occurring between grounded conductors or between them is extremely high.

If the liquid is flammable and there is air in the pipe or near the outlet, there is an extremely high risk of an explosion.On the other hand, in a gas atmosphere with a high concentration above the explosion limit or in an inert gas atmosphere, such as in a liquefied gas storage tank. When injecting into the air, there is no danger of explosion even at high flow velocities.

The present invention relates to receiving equipment that is easy to operate and maintain when receiving flammable liquid from the upper end of a vertical pipe when air is present in the storage tank. The present invention relates to a liquid receiving facility having an inert gas supply line for inactivating the receiving path, and further having a horizontal discharge pipe for static electricity removal in the storage tank.

Now, to explain one embodiment, a protective shaft 2 or a pot 3 having an inner diameter larger than the vertical receiving pipe 1 is placed very close to the bottom of the storage tank 4 so that the vertical receiving pipe 1 of the liquid receiving hole device can be inserted into the lower end. Insert into the shaft 2 or pot 3 a vertical receiving pipe 1 whose lower end is cut at an angle of 45°, and connect the lower end of the vertical receiving pipe 1 to the bottom of the shaft 2 or pot 3. The inert gas supply nozzle 8 with a valve 7 is provided at the top of the vertical receiving pipe 1, and the inert gas supply nozzle 8 with a valve 9 is provided at the top of the shaft 2 or pot 3. A supply nozzle 10 is provided, and a horizontal discharge pipe 11 with an inner diameter equal to or larger than that of the vertical receiving pipe 1 is installed at a position higher than the lower end of the vertical receiving pipe 1 on the side of the shaft 2 or pot 3 with a length effective for mitigating static electricity. The horizontal discharge pipe 11 and the grounded storage tank bottom plate 12 are connected by a ground wire 13, and the vertical receiving pipe 1 and the shaft 2 or pot 3 are also connected to the outside by a ground wire 14.

With the above-mentioned configuration, the present application uses inert gas while the receiving valve 15 provided in the front part of the nozzle 8 provided in the upper part of the vertical receiving pipe 1 and the pressure relief valve 16 provided in the lower part of the valve 9 of the nozzle 10 are closed. Supply valves 7 and 9 were opened to supply inert gas, and after filling the inside of the vertical intake pipe 1 shaft 2 or pot 3 and horizontal discharge pipe 11 with inert gas, valve 7 was closed and valve 9 was opened. In this state, while continuing to supply inert gas, the receiving valve 15 is opened and the liquid receiving hole is started.

Until the horizontal discharge pipe 11 in the storage tank 4 is submerged in the liquid, the liquid is supplied to the receiving valve 15 at a flow rate that is generally considered safe due to static electricity countermeasures, and is accelerated by gravity in the vertical receiving pipe 1. The liquid drops and accumulates in the shaft 2 or pot 3, and as the supply continues, the liquid level rises at a speed lower than the flow rate at the receiving valve 15, and after the lower end of the vertical receiving pipe 1 is completely immersed in the liquid, the liquid The surface reaches a height at which the horizontal discharge pipe 11 is installed, and the liquid is discharged from the discharge port of the horizontal discharge pipe 1 into the storage tank 4.

When the horizontal discharge pipe 11 is submerged in the liquid accumulated in the storage tank 4, the inert gas supply valve 9 is closed, the pressure relief valve 16 is opened, and the supply flow rate of the liquid receiving hole device is set at an economical flow rate considering static electricity countermeasures. Acceptance is performed after switching to .

Incidentally, the vertical receiving pipe, shaft, pot, etc. are not only installed inside the tank as shown in FIG. 2, but may also be installed outside the tank or inside the concrete side wall of the tank as shown in FIG.

In the present application, as described above, a protection shaft 2 or a pot 3 having an inner diameter larger than the vertical receiving pipe 1 is positioned close to the bottom of the storage tank 4 so that the lower end thereof is positioned so that the vertical receiving pipe 1 of the liquid receiving hole device can be inserted therein. In this way, the vertical receiving pipe 1 whose lower end is cut at an angle of 45° is inserted into the shaft 2 or the pot 3, and the lower end of the vertical receiving pipe 1 is placed on the bottom of the shaft 2 or the pot 3 so that there is no obstruction during discharge. An inert gas supply nozzle 8 having a valve 7 is provided at the top of the vertical receiving pipe 1, and an inert gas supply nozzle 10 having a valve 9 is provided at the top of the shaft 2 or pot 3. installation, shaft 2 or pot 3
A horizontal discharge pipe 1 with an inner diameter equal to or larger than that of the vertical receiving pipe 1 is placed at a position higher than the lower end of the vertical receiving pipe 1 on the side of the
1 with a length effective for mitigating static electricity, and connect the horizontal discharge pipe 11 and the grounded storage tank bottom plate 12 with a ground wire 13.
Since the vertical receiving pipe 1 and the shaft 2 or pot 3 are also connected to the outside with the ground wire 14, there is no risk of explosion even at a high flow velocity to inactivate the receiving route, and by providing a horizontal discharge pipe. Can eliminate static electricity,
Further, it has the advantage that the flexible liquid can be safely received in the storage tank without requiring complicated equipment or repairs in difficult locations.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views of conventional storage tanks, Figures 3 and 4 are cross-sectional views of the storage tank of the present application, and Figures 5 and 6 are main parts of shaft and pot cases. Part cutaway front view, No. 7
The figure is a sectional view of the storage tank when a pipe line is provided outside the storage tank. 1... Vertical receiving pipe, 2... Shaft, 3... Pot, 4... Storage tank, 7...
...Valve, 8...Inert gas supply nozzle, 9...Valve, 10...Inert gas supply nozzle, 11...Horizontal discharge Tube, 12...
...Storage tank bottom plate, 13...Ground wire, 14...
····ground wire.

Claims (1)

[Scope of utility model registration request] In order to insert the vertical receiving pipe 1 of the liquid receiving hole device, a protective shaft 2 or pot 3 having an inner diameter larger than the vertical receiving pipe 1 is provided so that its lower end is located close to the bottom of the storage tank 4, and the shaft 2 or insert the vertical receiving pipe 1 whose lower end is cut at an angle of 45° into the pot 3, and bring the lower end of the vertical receiving pipe 1 as close as possible to the shaft 2 or the bottom of the pot 3 so as not to cause any trouble during discharge. An inert gas supply nozzle 8 having a valve 7 is provided at the top of the vertical receiving pipe 1, and an inert gas supply nozzle 10 having a valve 9 at the top of the shaft 2 or pot 3.
A horizontal discharge pipe 11 with an inner diameter equal to or larger than that of the vertical receiving pipe 1 is installed at a position higher than the lower end of the vertical receiving pipe 1 on the side of the shaft 2 or pot 3 at a length effective for mitigating static electricity. This liquid storage tank liquid reception equipment is formed by connecting a discharge pipe 11 and a grounded storage tank bottom plate 12 with a ground wire 13, and also connecting the vertical reception pipe 1 and shaft 2 or pot 3 to the outside with a ground wire 14.