JPH10245571A - Process and apparatus for separating and recovering sand-contaminated heavy oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process and an apparatus for completely separating heavy oil lumps drifted on shore and recovered together with sand into sand and heavy oil. SOLUTION: Sand-contaminated heavy oil lumps are introduced into a basket tumbled in a heavy liquid of saturated brine filled into an oil/sand separation tank 1 and heated to high temperature, crushed into finer easily meltable lumps. The finer lumps are separated into sand and heave oil, which floats owing to the difference between their specific gravities, and only the supernatant heavy oil is separated and recovered from a discharge trough 10. On the other hand, the sand having a larger specific gravity and settled to the sand collection pit 13 on the bottom a sand separation tank 1 is pulled up from the tank with a sand pull up bucket conveyor 12 and heated again to remove the residual oil, and continuously discharged from a sand discharge trough by means of a sand discharge trough conveyor 16. The heavy oil lumps are introduced into the basket 4 through a net conveyor 24. Sand not contaminated with heavy oil is screened by vertically tumbling the conveyor 24, and only the heavy oil lumps can be introduced. Therefore, a large amount of sand-contaminated heavy oil lumps can be continuously treated without extra energy consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for recovering contaminated heavy oil collected along with sand and foreign matter from sand, foreign matter and heavy oil when recovering heavy oil that has leaked from a tanker accident or an oil storage facility and drifted to the shore. It relates to a method and apparatus for separating and recovering well.

[0002]

2. Description of the Related Art At present, heavy oil that has drifted on a sandy beach has been scattered or swept up by waves when it is hit by waves.
On top of that, drifting sand covers heavy oil and sand in multiple layers, and at present it has to rely on manual recovery. Therefore, the heavy oil recovered in the drum has a large amount of sand (70% sand, 20% water, 6-7% oil) in the component analysis.
Difficulties also arise during incineration. In the separation and recovery of contaminated heavy oil mixed with sand, an experiment was conducted in which the floating oil on the water surface was sucked up and centrifuged (eg, Kevin Costner), but the viscosity of heavy oil was high and separation was difficult. Separation and recovery experiments using MJP (Mochizuki-type air-mixing jet pump) were also conducted, but there was a problem such as oil remaining in the separated sand.
On the other hand, there is no way to treat a large pile of sand with an oil content of 5% accumulated by civil engineering machinery, and landfill disposal of sand with an oil content of less than 5% is being considered, and environmental destruction such as soil and groundwater contamination is being considered. Is feared.

[0003]

[Problems to be solved by the invention] Human power (volunteer)
The foreign bodies such as sand and seaweed are mixed in the heavy oil mass recovered by the method, but the technology to separate heavy oil and sand from it has not been established yet. If the contaminated heavy oil is completely separated at the recovery site and only the heavy oil is collected in drums, the weight will be reduced and the transport volume will be reduced, and it will be possible to reuse it other than incineration. On the other hand, if the separated and collected sand is put into the sea, The small amount of residual oil is treated and purified by petroleum-degrading bacteria, which also preserves the declining beaches. The present invention provides a technique for completely separating recovered heavy oil mixed with foreign substances such as sand into heavy oil and sand.

[0004]

SUMMARY OF THE INVENTION The present invention separates heavy oil lumps contaminated with sand and the like into sand and heavy oil. Since heavy oil with few volatile components drifted on the sandy beach has a large specific gravity and extremely high tackiness, in order to separate recovered heavy oil containing a large amount of sand and seaweed, a heavy oil mass is stirred in a water tank heated to a high temperature. It is crushed, melted, and separated and recovered according to the difference in specific gravity. The second object of the present invention is to facilitate the flotation separation of heavy oil lumps having a large specific gravity with the heavy liquid of high-concentration salt water to improve the recovery rate.
According to a third aspect of the present invention, the collected heavy oil lumps are put into a wire mesh basket provided below the surface of the high-temperature water tank, and the basket is rotated or rocked to crush and refine the heavy oil lumps to facilitate melting. , For removing seaweed and foreign matter remaining in the basket. The heavy oil eluted from the basket into the high-temperature water tank has a reduced viscosity and easily separates from sand, and floats on the water surface due to the difference in specific gravity with high-concentration salt water. The invention described in claim 4 is:
Sand with a higher specific gravity than salt water settles at the bottom of the separation tank, so the bottom of the tank is set at the angle of repose of sand in water (about 30 °).
With the above inclination, the sand is collected in the sand collecting tank at the deepest part of the water tank, and the sand and the sand are lifted by a bucket conveyor, jet conveyor, bubble pump, etc. into the secondary treatment tank on the surface of the water higher than the surface of the oil and sand separation tank. The oil remaining in the sand is completely separated and removed by reheating with a burner and washing with stirring. The rewashed sand is recovered from the secondary treatment tank by using a trough conveyor. On the other hand, the oil film floating on the water surface in the secondary treatment tank is returned to the oil and sand separation tank together with water. According to a fifth aspect of the present invention, the enormous amount of sand with a low content of heavy oil accumulated in the civil engineering machinery contains a large amount of sand not contaminated with oil, and the excess sand is removed by a mechanical sieve. By putting only heavy oil lumps mixed with sand into the separation water tank, it is possible to prevent the temperature of the hot water in the tank from dropping and to save energy for heating. Dry sand that has not been contaminated with oil can be easily sieved with a fine sieve, so that continuous excess surplus can be obtained by intermittently applying a shocking vibration in the vertical direction to the driving chain of the net conveyor. Only heavy oil lumps can be put into the separation tank while sieving the sand. According to the sixth aspect of the present invention, when the excess sand is sieved by the apparatus according to the fifth aspect, if the sand is wet or contains a large amount of water, it is difficult to sieve with a fine sieve. However, since the sand is dispersed in water, it can be easily sieved, and heavy oil does not easily adhere to the wet sieve. Therefore, the lower end of the net conveyor is submerged in a tank filled with seawater, and heavy oil lumps mixed with sand are poured onto the net conveyor in seawater to wash away excess sand. When this method is used on the shore, the surrounding area is surrounded by a fine wire mesh to prevent heavy oil lumps from leaking. However, since the heavy oil dissolved in seawater floats on the sea surface, surround the area with an oil fence and use a separately prepared floating oil. It must be collected by a collecting device.

[0005]

[Function] A heavy oil mass containing sand and foreign matter from which heavy oil collected on a sandy beach is recovered has no volatile components and a specific gravity of 1.002 to 1.007.
It sinks greatly in the water. In addition, since sand particles with a specific gravity of about 2.6 are mixed, they sink in seawater with a specific gravity of 1.03.
Salt is added to seawater and floated and separated according to the difference in specific gravity using a saturated saline solution with a specific gravity of 1.2. In addition, the viscosity of the recovered heavy oil is so large that it does not easily dissolve at room temperature. Therefore, it is necessary to heat saturated brine to a high temperature of 70 ° C to 80 ° C to soften the recovered heavy oil and stir it so that it can be easily separated from sand. is there. Also, since the recovered heavy oil is a large lump and sinks when poured directly into high-temperature salt water, it is poured into a coarse-meshed wire mesh basket installed in the upper layer of the surface of the oil and sand separation tank. By rotating or rocking the basket, the heavy oil lumps are crushed and refined to make it easier to melt and prevent the heavy oil lumps from settling at the bottom of the water tank. The basket is also intended to remove seagrass and foreign substances contained in the recovered heavy oil mixed with sand. Heavy oil softened at high temperature has good fluidity and has a lower specific gravity than saturated brine, so it easily floats and separates. However, some heavy oil lumps that float with sand without melting sufficiently, so only the supernatant is used. Provide a partition plate that flows down, and a partition plate is provided above the water surface to prevent the supernatant liquid from passing through to the recovery tank, and the heavy oil re-emerged from the lower part of the partition plate is transferred to the recovery tank. Make it flow and collect it from a discharge pipe into a drum. On the other hand, the sand that has settled in the oil / sand separation tank is accumulated in the sand collecting pit along the slope of the bottom, so it is pulled up to a secondary treatment tank with a slightly higher water level than the oil / sand separation tank by a bucket conveyor or the like, and reheated. The residual oil is completely suspended and separated, and then lifted and collected with a trough conveyor. Since a thin oil film floats on the water surface of the secondary treatment tank, it is returned to the oil and sand separation tank together with excess water by head.

[0006]

Embodiments of the present invention will be described with reference to the accompanying drawings. As an example, Fig. 1 shows a top view of an oil and sand separation tank, and Fig. 2 shows a side view. The bottom surface 2 of the oil / sand separation tank 1 in FIG. 1 is inclined more than the angle of repose of the sand (about 30 °) so that the sand naturally flows down to the sand collecting pit 13. Its bottom 2
The oil-sand separation tank is heated by a heating burner 3 from below the oil-sand separation tank 1, and the oil-sand separation tank 1 is filled with high-temperature saturated brine. A basket 4 made of a coarse mesh is provided on the water surface at one end, and heavy oil lumps mixed with sand are continuously fed into the basket by a belt conveyor or a net conveyor 24. FIG. 3 shows an AA ′ cross section. When the basket 4 is oscillated by the crank 5 and the swing lever 6, the heavy oil mass in the basket 4 is crushed and fragmented and melted, and the heavy oil and sand are easily separated.
The seaweed and refuse collected together with the heavy oil lumps remain in the basket 4 so that they can be collected and removed. The heavy oil melted at a high temperature has good fluidity and floats on the water surface, and the separated sand precipitates at the bottom and flows down to the sand collecting pit 13. FIG. 4A shows the partition plate 7, and FIG. 4B shows the partition plate 8. Since the heavy oil that has floated still contains heavy oil lumps containing sand, a partition plate 7 shown in FIG. 4A is provided to prevent the heavy oil lumps from flowing directly into the heavy oil recovery box 9 and only the supernatant on the water surface is moved downstream. Pour out. Fig. 4
A partition plate 8 shown in (b) is provided to cut off the water surface portion, and the heavy oil floating from below the inclined cutout portion at the lower portion of the partition plate 8 is sent to the recovery tank 9. FIG. 5 shows a BB ′ cross section. The heavy oil floating from below the partition plate 8 flows over the upper edge of the recovery box 9, flows out of the heavy oil discharge port 10, and is collected in the oil collection tank 18 by the heavy oil discharge gutter 11. The partition plates 7 and 8 can be adjusted up and down as appropriate according to the oil processing situation.

An example of an apparatus for treating sand in the oil / sand separation tank 1 will be described. FIG. 6 shows a section taken along the line CC ′, and FIG. 7 shows a section taken along the line DD ′. The sand collecting tank 1 flows down the slope 2 at the bottom of the oil and sand separation tank 1
The sand accumulated in 3 is lifted by a bucket conveyor 12 shown in FIG. 6 into a secondary treatment tank 14 having a water level higher than the water level of the oil and sand separation tank 1 by H. The secondary treatment tank 14 is heated from the bottom by a reheating burner 15, and the residual oil adhering to the sand is separated and floats on the surface of the water lifted together with the sand. The oil is returned to the oil and sand separation tank 1 by the return pipe 18 using the above.
The sand re-washed in the secondary treatment tank 14 and deposited on the bottom is shown in FIG.
Are discharged from the sand discharge gutter 17 by the trough conveyor 16 shown in FIG.

An inspection window 19 is provided in a heating section below the oil and sand separation tank 1 in FIG. 2, and a water tank 20 for fresh water using residual heat is installed on a wall surface above the inspection window. It can be used for replenishing water to the tank and for cleaning. Further, the exhaust of the heating burner 3 is discharged from the exhaust hole 21 to the exhaust pipe 22.
It is released to the atmosphere via. It is necessary to install a simple flue gas desulfurization device 23 when using the recovered heavy fuel oil or the like as fuel.

In order to operate the oil / sand separation tank 1 efficiently, it is necessary to continuously feed the heavy oil lumps by a constant amount while monitoring the treatment state. For this purpose, a belt conveyor or a net conveyor is suitable. FIG. 8 shows the net conveyor 24.
An example of a device for supplying heavy oil lumps by means of is shown. The figure shows a state in which the lower part of the net conveyor 24 is immersed in the water tank 25, but this may not be necessary depending on the state of the sand. When a heavy oil lump mixed with sand is put on the net 26 of the net conveyor 24 and put into the oil / sand separation tank 1, sand not contaminated with oil is sieved off by the net, and only the heavy oil lump is put into the basket 4. It is. Net 2
The sand sieved in Step 6 is the shielding plate 27 shown in the EE 'section.
This prevents the sand from dropping on the upper side of the return net 26 'by dropping to both outer sides of the conveyor 24. FIG. 9 is a detailed view of a mechanism for applying vibration to the net 26. If the sand is hard to fall from the net 26, as shown in FIG. 9, a chain provided with a rod 29 with a roller at every several pitches of the chain is run on a chain guide rail provided with a serrated protrusion 28. A vertical shock is applied to the chain to facilitate sieving sand from the net 26. By making each interval l of the sawtooth-shaped projections 28 not coincide with an integral multiple of the chain pitch p, each part of the net conveyor 24 can be vibrated alternately.

[0010]

According to the present invention, heavy oil that has drifted to the shore is collected together with sand and seaweed, packed in drums, transported to a processing company, and incinerated. However, since it contains a large amount of sand and water, a huge amount of energy is consumed. Necessary and difficult to process. The present invention relates to a method in which a heavy oil mass having a high viscosity due to a volatile component being vaporized is poured into a high-concentration salt water heated to a high temperature to lower the viscosity of the heavy oil and melt, and separated from sand by a difference in specific gravity. . Therefore, the recovered heavy oil is reduced in weight and the amount of transportation is significantly reduced, and since only heavy oil components are contained without sand or foreign substances, the following effects unique to this system can be obtained. Separated and recovered sand is heat-treated compared to other methods of simply stirring and separating, and has the distinctive effect of completely removing heavy oil attached to the sand. It was found that the smell was slightly left on the sand after the treatment, but it disappeared completely after 2-3 days. Saturated salt water is used as a heavy liquid to increase the separation efficiency due to the difference in specific gravity. The salt water analysis showed that the COD was less than 20 ppm. Also, since the quantity is only the capacity of the oil and sand separation tank, returning it to the ocean as it is does not affect the natural environment at all. Furthermore, the removal of sand that is not contaminated with heavy oil in advance reduces the amount of heat energy consumed, and also has the added effect of collecting and removing foreign substances such as seagrass and dust mixed in the sand. .

[Brief description of the drawings]

FIG. 1 is a top view of an oil and sand separation tank of an embodiment.

FIG. 2 is a side view of the oil and sand separation tank of the embodiment.

FIG. 3 is an explanatory view of a mechanism for swinging a basket in an oil-sand separation tank.

FIG. 4 (a) is an explanatory view of an upstream partition plate, and FIG. 4 (b) is an explanatory view of a downstream partition plate.

FIG. 5 is a sectional view of a heavy oil recovery section.

FIG. 6 is a cross-sectional view of a bucket conveyor for raising sand from a sand collecting pit.

FIG. 7 is a cross-sectional view of a trough conveyor for sand removal from a secondary treatment tank.

FIG. 8 is a cross-sectional view of a net conveyor section for putting heavy oil lumps into the oil and sand separation tank.

FIG. 9 is a detailed explanatory diagram of a net vibrating mechanism of a feeding net conveyor section.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Oil-sand separation tank 3 Heating burner 4 Heavy oil chunk crushing basket 5, 6 Basket swinging mechanism 10 Recovery heavy oil discharge gutter 14 Sand pulling bucket conveyor 15 Secondary treatment tank 18 Sand discharge trough conveyor 19 Sand discharge gutter 21 Shimizu Water heater tank 25 Net conveyor for loading heavy oil lumps 28 Serrated guide rail for net conveyor vibration

Claims (6)

[Claims] 1. A high-viscosity heavy oil mass that has drifted ashore and is contaminated with sand or the like is put into a water tank filled with warm water, stirred and crushed to lower the viscosity of the heavy oil and to form sand and heavy oil. The sand is settled at the bottom of the tank due to the specific gravity difference,
A method for separating and recovering contaminated heavy oil, in which heavy oil having a specific gravity lower than that of hot water is floated to the upper part of the tank and collected. 2. For separation of heavy oil or the like whose specific gravity has increased due to vaporization of volatile components, a water tank is filled with high-concentration salt water as a heavy liquid to increase the difference in specific gravity from heavy oil to increase the efficiency of flotation separation. The method for separating and recovering contaminated heavy oil according to claim 1, wherein the method is improved. 3. A heavy oil mass containing sand is poured into a wire mesh basket placed under the upper surface of the water in an oil / sand separation tank, and the basket is rotated or rocked to finely crush the heavy oil mass. A separation and recovery system for contaminated heavy oil, characterized by promoting the melting of heavy oil lumps and facilitating oil and sand separation. 4. The sand settled at the bottom of the oil / sand separation tank is lifted by a bucket conveyor or the like into a secondary treatment tank having a water surface higher than the water surface of the separation water tank, reheated and stirred and washed to remove residual oil in the sand. An oil characterized by having a secondary treatment tank for completely removing the residual oil content of the recovered sand, which is configured to remove and return the oil film floating on the water surface of the secondary treatment tank to the oil sand separation tank together with the water Sand separator. 5. Heavy oil lumps mixed in a large amount of sand are sieved in advance with excess sand not contaminated with oil through a fine-meshed sieve, and only heavy oil lumps mixed with sand are put into a separation and recovery tank. To perform this operation continuously, a net conveyor is used, but sand and heavy oil lumps are characterized by having a vibration mechanism that intermittently applies vertical shocking vibration to the driving chain of the net conveyor. Sieving separation equipment. 6. A method for separating heavy oil lumps mixed with sand, wherein in the case of wet sand or sand containing a large amount of water, the lower part of the net conveyor is immersed in a water tank or sea filled with water, The wet-sieving separation apparatus for sand and heavy oil according to claim 4, wherein the heavy oil lumps mixed with sand are poured onto a net conveyor in seawater to wash away excess sand.