JPS6316191B2 - - Google Patents

Description

Detailed Description of the Invention This invention crushes and dissolves the sludge accumulated inside the oil tank by jetting oil, drains and removes the internal liquid by the suction action of the suction tank, and after thoroughly cleaning with oil, cleans it with water or hot water. The present invention relates to a method for cleaning an oil tank, characterized in that the final cleaning is carried out by the following methods, and the drained liquid is separated from oil and water.

To remove the wax-like sludge that accumulates inside the oil tank, a high-pressure liquid is injected from an injector installed inside the tank to crush and dissolve the sludge.
A method is adopted in which the liquid from the molten sludge and the injected liquid are discharged to the outside of the tank. In this case, the liquid from the sludge and the sprayed liquid, that is, the liquid that accumulates at the bottom of the tank, must be drained out of the tank as quickly as possible. The reason for this is that when sludge is immersed in liquid, the crushing and dissolving effect due to the injection pressure of high-pressure liquid is reduced, and when exposed to gas, the above effect increases significantly. If it is slow, the sludge will be immersed in the liquid.

Conventionally, in order to discharge the liquid, a suction pipe connected to a pump is exposed to the bottom of the tank through a manhole or the like, and the liquid inside the tank is suctioned and removed by driving the pump. However, this method allows solids such as sludge and rust from the bottom of the tank to enter the pump, reducing pump efficiency and, in extreme cases, damaging the pump. Also, when the liquid level is low, the end of the suction pipe opens into the gas in the tank, so the pump may suck in the gas. Even if this happens, it will take a long time until the liquid is re-suctioned, and the suction ability of the liquid remaining in the tank will be reduced, resulting in a significant reduction in the liquid removal effect of the tank. Furthermore, even after cleaning the inside of the tank with oil, etc., people enter the tank to perform various inspections or perform maintenance work, so in order to remove the oil film on the inside, the tank is finally washed with water. Must be washed with warm water.

The present invention was proposed in order to solve the above-mentioned conventional drawbacks, and the sludge accumulated inside the oil tank is crushed and dissolved by oil injection, and the internal liquid is discharged and removed by the suction action of the suction tank. , After cleaning most of the inside of the tank in this way,
The final cleaning of each internal surface of the tank, especially the wall and ceiling surfaces, is performed with water or warm water by switching operations using a valve, and the waste liquid from this cleaning is sucked into a suction tank and separated from oil and water.

Therefore, according to the present invention, the inside of the tank is cleaned with oil and the final cleaning with water or warm water, and by instantly switching between the two cleanings, there is no time wastage, and the final cleaning is performed. The oil-water mixture discharged by the tank is separated into oil and water, and the water is recycled again for final cleaning, so that almost no oil components are present inside the tank after the final cleaning.

The method of the present invention will be explained below with reference to a floating roof type oil tank shown in the embodiment of the drawings.

A floating roof type oil tank 1 supports a floating roof 2 with a large number of supports 3 when removing sludge a deposited inside, and also extracts as much liquid b from inside as possible. An injector 4 that injects liquid at high pressure is hung from the floating roof 2 and is located inside the tank, and the high-pressure liquid from the injector 4 is directly injected into the sludge a to crush and melt it into a liquid. It is.

According to the present invention, the outflow pipe 5 for discharging the fluid inside the tank is led into the tank from the manhole 1' of the tank 1, and the suction port 6 provided at the tip of the outflow pipe 5 is made to face the inside of the bottom surface of the tank 1. , or the drain pipe 5 is connected to the drain nozzle section 7 provided in the tank 1.
The other end of the outflow pipe 5 is connected to the upper surface of an airtight suction tank 8. A suction pipe 10 of a gas suction pump 9 is connected to the upper surface of the suction tank 8, and a discharge pipe 11 of the suction pump 9 is opened into the tank 1 from a manhole 1' or a roof manhole 2'.

In addition, a suction pipe 13 connected to the suction side of a liquid suction pump 12 is connected to the suction tank 8, and a discharge pipe 14 of the suction pump 12 is connected to a first valve 15 in the middle.
It is connected to the oil storage tank 16 through the intervening.

As this oil storage tank 16, an empty oil tank installed in parallel with the tank 1 may be used.

A pipe 19 connected to the suction side of the pump 17 and provided with a second valve 18 in the middle is connected to the oil storage tank 16, and the discharge port of the pump 17 and the injector 4 are connected by a connecting pipe 20.

Further, a branch pipe 2 having a third valve 21 is connected to the discharge pipe 14 between the suction pump 12 and the first valve 15.
2 is connected, and the other end of the branch pipe 22 is connected to the inflow side of the oil/water separator 23. The oil/water separator 23
The oil outflow pipe 24 of the oil water separator 23 is connected to the discharge pipe 14 on the downstream side of the first valve 15 by providing a fourth valve 25 in the middle, and the water outflow pipe 26 of the oil/water separator 23 is connected to the fifth valve 25 in the middle.
A valve 27 is provided and connected to a heater device 28.
A steam inflow pipe 30 provided with a sixth valve 29 is connected to the heater device 28, and a hot water pipe 31 extending from the heater device 28 is connected to the pump 17 and the second valve 1.
Connect to pipe 19 between 8 and 8.

Note that a water inflow pipe 33 that is opened and closed by a seventh valve 32 is connected to the suction tank 8 .

In the above configuration, in order to inject oil into the tank 1 to clean the sludge a while crushing and dissolving it, the suction pumps 9, 12, and 17 are driven, the first valve 15 and the second valve 18 are opened, and the second valve 18 is opened. 3rd valve 21, 4th valve 25, 5th valve 27, 6th valve
Valve 29 and seventh valve 32 are closed.

When the suction pump 9 is driven, the inside of the suction tank 8 becomes negative pressure, and a suction action is generated at the suction port 6, so that the liquid accumulated in the lower part of the tank 1 is sucked and flows into the suction tank 8 from the outflow pipe 5. When the liquid in the suction tank 8 is discharged from the suction pipe 13 by driving the suction pump 12, a large negative pressure is created in the suction tank 8 together with the action of the suction pump 9, so that the liquid in the tank 1 is continuously discharged. can be sucked into the suction tank 8.

Further, the liquid sucked into the suction pump 12 flows into the oil storage tank 16 from the discharge pipe 14, and the liquid sucked into the suction pump 12 flows into the oil storage tank 16.
The oil in the oil storage tank 16 is pumped into the pipe 1 by the drive of
9 through a connecting pipe 20, and is injected at high pressure from the injector 4.

Therefore, the oil in the tank 1 flows into the suction tank 8 from the outflow pipe 5, flows from the suction pipe 13 through the discharge pipe 14, flows into the oil storage tank 16, and then flows into the oil storage tank 16 through the pipe 19.
A circulating flow is transmitted through the connecting pipe 20 and injected at high pressure from the injector 4, and in particular, the sludge a in the tank 1 is crushed and dissolved by the high-pressure injection of oil from the injector 4.

When the sludge a has been sufficiently crushed and dissolved in this manner and most of the oil in the tank 1 has been discharged, a final cleaning is performed with hot water. In the case of this hot water cleaning, each pump 9, 12, 17 is driven as is, and the first
While closing the valve 15 and the second valve 18, the third valve 21, the fourth valve 25, and the fifth valve 2 are closed.
7. Open the sixth valve 29 and seventh valve 32.

When the seventh valve 32 is opened, water flows into the suction tank 8, and the oil-water mixture discharged from the pump 12 is transmitted from the discharge pipe 14 through the branch pipe 22 to the oil-water separator 2.
3. The oil flowing out from the oil-water separator 23 flows from the outflow pipe 24 downstream of the discharge pipe 14 and into the oil storage tank 16. Water flowing out from the oil-water separator 23 is led from the water outflow pipe 26 to the heater device 28, where it is mixed with steam from the steam inflow pipe 30 and heated, and then transmitted from the hot water pipe 31 through the pipe 19 and connected by the pump 17. tube 20
is fed under pressure and injected at high pressure from the injector 4.

When hot water is injected at high pressure from the injector 4, this hot water cleans the oil film on each surface inside the tank, particularly on the walls and the ceiling surface which is the lower surface of the floating roof 2. The cleaning water then flows into the suction tank 8 which is under reduced pressure by the suction pump 9, and the water content in the suction tank 8 gradually increases and flows out from the pump 12. Therefore, the water injected into the tank also flows into the suction tank 8 from the outflow pipe 5, passes from the suction pipe 13 to the discharge pipe 14, is led from the branch pipe 22 to the oil-water separator 23, and then flows into the water outflow pipe 26.
The water is then heated by the heater device 28, passes through the hot water pipe 31 and the pipe 19, is fed under pressure to the connecting pipe 20 by the pump 17, and becomes a circulating flow that is injected at high pressure from the injector 4.

When the inside of the tank is sufficiently cleaned by such circulating flow of hot water, the final cleaning is completed.

As described above, according to the present invention, the sludge accumulated inside the tank 1 is crushed and dissolved by the high-pressure oil injected from the injector 4, and the liquid generated by the crushing and dissolution of the sludge and the injected liquid are absorbed by the negative pressure of the suction tank 8. It consists of oil cleaning by suction and flowing into the suction tank 8, and final hot water cleaning which is carried out when sludge is no longer present and there is almost no oil in the tank due to oil cleaning. Even if the liquid level in the tank 1 becomes low and the gas in the tank is suctioned from the suction port 6, the suction pump 9 can be driven to maintain negative pressure in the suction tank, reducing the liquid suction efficiency. I have nothing to do.

Also, when cleaning oil, use a sprayer to clean tank 1.
When removing the sludge that accumulates inside the
To prevent explosions caused by static electricity, the inside of tank 1 is filled with inert gas to create an inert atmosphere, but when the inert gas in the tank is sucked, air flows in through the gap and the gas composition changes due to an increase in oxygen concentration. may change and it may not be possible to maintain an inert atmosphere.

However, according to the embodiment of the present invention, the discharge pipe 11 of the suction pump 9 is opened inside the tank 1, so even if gas is inhaled from the suction port 6, it is immediately returned to the tank 1, and the gas composition is changed. Since no change occurs, the oxygen concentration within the tank 1 does not increase. All the exhaust air sucked from inside the tank is sent into the tank, so the gas atmosphere inside the tank is not changed, and gases generated from inert gas and oil are not dissipated around the tank, causing odors and The risk of ignition can be prevented.

According to the embodiment of the drawing, the suction tank 8 is equipped with a pressure gauge 3.
4 and a liquid level gauge 35 are facing, and the pressure gauge 34
to the suction pump 9, and the liquid level gauge 35 to the suction pump 12.
are electrically or pneumatically connected to each other. The pressure gauge 34 detects when the pressure in the suction tank 8 reaches a set value and turns the suction pump 9 on or off.The liquid level gauge 35 detects when the liquid level in the suction tank 8 reaches the set level. This turns the suction pump 12 on or off.

The suction tank 8 is determined by this pressure gauge 34 and liquid level gauge 35.
Since the internal pressure and liquid volume of the tank 1 can be constantly controlled, the work of removing the internal distillate from the tank 1 can be automated. Furthermore, the inside of the suction tank 8 is divided by a partition plate 36 made of plate material or net material, etc.
A chamber 37 and a second chamber 38 are configured, and the liquid from the outflow pipe 5 and the inflow pipe 33 flows into the first chamber 37.
When the liquid in the chamber 37 overflows or passes through the mesh material, it is stored in the second chamber 38, and the liquid in the second chamber 38 is sucked by the suction pump 12.

With such a configuration, even if the liquid flowing into the suction tank 8 from the outflow pipe 5 contains solids such as metals, the solids will settle in the first chamber 37, so the suction pump Not guided by 12,
Since nothing other than liquid is collected, the suction pump will not be clogged or damaged. Moreover, the solid content in the first chamber 37 can be discharged from the drain 39 or the manhole 40 when the work is stopped.

In summary, according to the present invention, the internal liquid in the oil tank is not directly discharged by a pump, but
Since the liquid is discharged by the suction action of the negative pressure of the suction tank, the suction efficiency is not reduced even if gas is mixed in during discharge, and the internal liquid can be continuously suctioned and discharged. In addition, since no solids are sucked into the pump, the operation of the pump is not obstructed and continuous work can be performed for long periods of time.Furthermore, solids do not pass through the collection path for the liquid that has been suctioned and removed. Management of tanks along the recovery path is also advantageous.

Furthermore, according to the present invention, the oil tank and suction tank are closed, and even if gas is inhaled from the suction port of the discharge pipe, it immediately returns to the oil tank, so there is no possibility of changes in the gas composition inside the oil tank. It is possible to reliably prevent the occurrence of odors and the risk of ignition.

Furthermore, according to the present invention, when cleaning the tank, the sludge is crushed and dissolved using oil, and after the oil has been sufficiently removed, each surface inside the tank is finally cleaned with warm water.Switching between the two types of cleaning can be done by operating multiple valves. Just do it. Therefore, if each valve is an electromagnetic valve, both cleaning operations can be electrically controlled, so there is no need to stop the cleaning process over time.

Furthermore, as shown in the drawings, this method is effective in removing sludge from a floating roof type oil tank, but it can also be carried out in the case of other oil tanks and liquid tanks.

In addition, in the present invention, the waste liquid from the cleaning process is removed by suction into a suction tank and separated into oil and water, so the separated oil can be reused, and the water can be recycled for cleaning or used as is.ゝThe treatment is extremely effective because it can be discharged.

[Brief explanation of the drawing]

The drawings are schematic diagrams showing an embodiment of the present invention.

Claims (1)

[Claims] 1. The suction port of the outflow pipe connected to the suction tank faces the inside of the oil tank, and a gas suction pump and a liquid suction pump are connected to the suction tank. The sludge is crushed and melted, and the oil accumulated inside is suctioned and supplied to the suction tank, which has a negative pressure due to the action of both pumps, and the oil supplied to the suction tank is supplied from the discharge pipe to the oil storage tank by the suction pump. When there is almost no oil left in the oil tank, the oil tank is cleaned by spraying water or hot water from the sprayer onto each surface inside the tank, and the cleaning liquid is sucked and removed into a suction tank under negative pressure. A method for cleaning an oil tank characterized by separating oil and water.