JPS584757B2 - Genyusuratsujijiyokiyohouhou - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a method for preventing solids such as wax contained in crude oil from depositing in the tank when storing crude oil in a tank constructed in the ground on a coast. ,
In particular, the present invention relates to a method in which the above-mentioned deposits are skillfully removed by heating and flowing groundwater that has leached out and accumulated in the lower part of the stored crude oil in a tank.

In recent years, the demand for petroleum products has increased rapidly not only from the energy perspective but also from the industrial perspective of chemical products, and as long as this is the case, it is strongly desired that the supply of petroleum products will always be flexible, regardless of whether it is an oil-producing country or an oil-consuming country. It is starting to become possible.

And its supply function is not limited to just a primary supply, but can no longer be ignored from the perspective of stockpiling, and as a matter of course, larger crude oil tanks are desired.

However, from an economic and industrial perspective, it is desirable to build such large tanks in close proximity to industrial plants and chemical complexes. Because construction is continued before the construction is complete, the momentum structure may become strained or unforeseen situations may occur under competing conditions, resulting in brittle fractures, uneven settlements, seismic cracks, etc., resulting in oil spills. As a result, pollution problems such as environmental destruction and marine pollution have become social issues.

In response to this, new technology has recently been developed in which geological surveys are conducted on designated suitable ground such as the coast, and a tunnel-type underground tank is constructed to stockpile large quantities.

Since the underground tank system has advantages such as being harmless to wind, low-cost and safe construction, and non-polluting operation, various structural designs and operation methods are being devised in various fields.

As mentioned above, underground tanks are a new technology, so on the one hand they have various advantages over above-ground tanks, but on the other hand, various unresolved problems have emerged. .

One of them is the problem of solid matter deposition.

In other words, since crude oil originally contains a small amount of delicate solid components such as wax, it accumulates at the bottom of the tank during long-term operation, becomes sludge, solidifies in some cases, and clogs the drain. In addition, after a long period of time, the increase in weight causes the center of gravity to drop, and there is also the disadvantage of causing inaccuracies in volume measurement. Measures such as heating and stirring and dispersion have been devised, but in underground tanks, there is a physical constraint that the tank is located inside the ground, and there is a disadvantage that such equipment cannot always be applied. However, it is expected that the operating efficiency will be poor even if
Furthermore, it also has the disadvantage of being unsuitable due to its large capacity.

The purpose of this invention is to solve the problem of sludge accumulation in underground tanks based on the above-mentioned conventional technology, and to solve the problem by dissolving the sludge that accumulates in the tank, preventing blockages in drains, etc., and stably dissolving the sludge. It is an object of the present invention to provide an excellent method for removing crude oil sludge from a tank, which allows tank operation and benefits the field of tank utilization in the energy industry.

The structure of the present invention in accordance with the above-mentioned object is to utilize groundwater that is necessarily present in an underground tank, thereby heating and circulating the crude oil solids deposited in the groundwater from above and releasing it into the bottom of the valley. The solid content in the underground tank is reduced by dissolving the sludge in the crude oil, making it dissolved in the crude oil, providing non-settling conditions, and separating the solid content during the flow process and removing it from the system. The gist of this is that technical measures have been taken to eliminate various obstacles caused by sedimentation.

Next, embodiments of the present invention that meet the above objectives will be described below with reference to the drawings.

Reference numeral 1 denotes an underground tank constructed on the basis of geological survey in suitable ground 2 such as the coast, the bottom part 3 of which is valley-shaped, a drainage pit 4 is provided at the end, and there is a tank connected to the ground surface. Communication holes 5 and 5' are provided between them, and a drainage pipe 7 equipped with a submerged pump 6, whose lower end faces the drainage pit 4, passes through and extends upward to separate the sludge at the ground surface. It is connected to an appropriate wastewater treatment device (not shown) via the device 8.

Similarly, an oil feed pipe 11 equipped with a pump 10 whose lower part faces the crude oil storage section 9 passes through the communication hole 5 and extends upward to communicate with the next-stage processing equipment.

Similarly, a pipe 12 for underground water circulation passes through the communication hole 5 with the submerged pump 13 at its lower end facing the drainage pit 4, and is passed through the other communication hole 5' through a heating type heat exchanger 14 at the ground surface. It is connected to a pipe 15 for hot water that passes downward through the pipe.

The hot water pipe 15 is connected to a hot water discharge pipe 16 along the longitudinal slope of the bottom 3 of the underground chamber 1, and the hot water discharge pipe 16 is connected to a second pipe 16. As shown in FIG. 3, a plurality of branch pipe nozzles 1B, 18, . There is.

Incidentally, reference numeral 19 denotes a crude oil inflow pipe that extends through the communication hole 5' and faces the inner bottom 3 of the underground tank 1.

After the installation of the above-mentioned equipment, sealers 20 and 21 are installed in the communication holes 5 and 5', and pressure water 22 is sealed between them.

In addition, 23 is a heating underground chamber on the side of the pipe 12 for underground water circulation out of the two partitioned parts of the drainage pit 4, and the opposite side, on the side of the drainage pipe I, is a sludge chamber 24. A movable weir 26 that can be raised and lowered is interposed in the support 25 constructed in the chamber, and although the movable weir 26 is not shown, it can be operated from the ground surface using a chain or the like so that it can be raised and lowered. has been done.

And the operation is also the submerged pump 13 of the drainage pump.
It is possible to perform up-and-down periodic operation by an appropriate device in synchronization with the above.

In the above configuration, when the sludge separator 8 is operated to maintain the underground water 27 seeping from the cave wall at the level of the weir 26 and the crude oil flows into the underground tank 1 through the inflow pipe 19, the crude oil flows above the ground water 27. is stored in

Then, when the submerged pump 13 is started and the heating type heat exchanger 14 is operated at the same time, the groundwater 27 rises from the heating underground water chamber 23 through the pipe 12 and enters the heating type heat exchanger 14.
The hot water is heated, the temperature rises, it descends from the hot water pipe 15, reaches the hot water discharge pipe 16, and is discharged from the branch pipe nozzle 18 along the bottom 3 of the underground tank 1, and at that time, Since the branch pipe nozzle 18 is directed toward the drainage pit 4, the groundwater 27 is heated and flows toward the drainage pit 4.

Therefore, even if subtle solids such as crude oil wax settle from the upper part of the groundwater 27 and are scattered into the groundwater 27, it will become dissolved due to the heating of the groundwater, and it will be sent through the branch pipe nozzle. No sedimentation due to fluidity due to pressure, groundwater 2
7 and flows into the drainage pit 23.

The groundwater 27 that has reached the drainage pit 23 leaks from the walls into the cavity, and the increased groundwater and sludge flow over the weir 26 and overflow into the sludge chamber 24, where it is sucked into the submerged pump 6 and drained from the drainage pipe 7. The sludge rises and reaches the sludge separator 8, where the sludge is separated and treated as appropriate, and the moisture is transferred to the next stage.

The above process is performed by replenishing the groundwater 27 flowing into the underground tank 1, so that the groundwater 27 is on the inner bottom 3 of the underground tank 1, that is, below the crude oil, and solids such as wax always settle from the crude oil into the groundwater 27. will continue to be removed from the system, and as long as this continues, the solid content will not be deposited and solidified in the bottom 3.

Furthermore, if the movable weir 26 is positioned in a fixed position, there is a tendency for solids to accumulate even slightly on the bottom 3, so in that case, as described above, the movable weir 26 may be moved up and down from the ground surface as appropriate at predetermined intervals. It is also possible to adjust and fluctuate the groundwater level 27 to secondarily disturb the fluidity of the groundwater 27 and provide a cleaner action to the bottom 3 to remove the deposited solids.

Furthermore, the movable weir 26 may be moved up and down in synchronization with the operating cycle of the drainage submerged pump 13.

During that time, the crude oil is appropriately transferred to the next stage process via the oil transfer pipe 11, and is replenished via the inflow pipe 19.

As described above, according to the present invention, the sedimentation of the solid content of crude oil stored on the groundwater interposed in the underground tank is dispersed in the groundwater, and the sedimentation and dispersion are carried out by heating and circulating the groundwater. The solid content does not precipitate out due to the rise in temperature due to heating and becomes dissolved, and because of the circulating flow, it does not settle at the bottom of the underground tank and can be skillfully separated and removed from the system using a separator installed in the circulation process. It will be done.

Therefore, underground tanks can constantly remove deposited solids by using the naturally existing intervening groundwater.
There is an advantage that a kind of purification action can be performed during operation.

Moreover, since the equipment can be easily installed without disturbing the underground tank, no maintenance is required.

Therefore, the underground tank does not cause pollution problems due to underground penetration due to the accumulation of solids, there is no change in capacity due to year-round operation, and there is no fear of blockage of equipment such as drainage pumps.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a side sectional view schematically explaining the whole, FIG. 2 is a front view corresponding to the same ■--■ section, and FIG. 3 is a plan view corresponding to the cross-section of the same. It is. 1...tank, 9...crude oil, 27...groundwater, 3
...bottom, 4...pit, 18...nozzle branch pipe,
16...Discharge pipe.

Claims (1)

[Claims] 1. In a method of removing settled sludge of crude oil stored in a tank installed underground by flowing groundwater interposed at the bottom of the crude oil, the bottom of the tank is separated from one end to the other end. A discharge pipe having a nozzle branch pipe is installed in the horizontal direction along the bottom of the valley, and is directed from the upstream side toward the pit so that it is in the ground water. In addition to arranging
A circulation pipe is formed between the pit and the upstream end of the discharge pipe through an above-ground heat exchanger and connected at the upstream end, and crude oil is supplied and stored on a predetermined amount of groundwater that accumulates on the entire bottom surface. A method for removing crude oil sludge, characterized in that the groundwater is heated and circulated by the discharge, and the crude oil sludge deposited in the groundwater is separated and removed from the system.