JP2005199121A - Oil recovery apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil recovery apparatus capable of remarkably enhancing the reduced quantity of oil included in soil irrespective of oil kind, contamination form, contamination history or else and reducing the load of water treatment by efficiently recovering the oil separated from soil particles. <P>SOLUTION: Oil/water separation is efficiently performed in such a manner that a slurry 40 in a tank main body 30 is circulated by a circulation pump 13, fine air bubbles are added into the circulated slurry 40 by using a fine air bubble generator 14, the slurry is injected in the tangential direction of the inner peripheral surface of the tank main body 6 and in the same direction through slurry supply pipes 8a, 8b and, thereby, a swirl flow is imparted to the slurry 40 in the tank main body 6. Oil separating working is performed efficiently. The separated oil floats up to the water surface while swirling and the floating oil is accumulated to the central part having a lower water level and deposited along an oil recovery plate 16 disposed on the upper end part of an oil recovery pipe 15. When the oil 41 is deposited up to the upper end of an upper opening part 17 of the oil recovery pipe 15, the oil 41 is allowed to continuously flow into the oil recovery pipe 15 from the upper opening part 17 and is recovered by an oil recovery tank 42. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an oil recovery device that recovers oil contained in water, and more particularly to improvement of oil recovery efficiency.

  Some soil excavated at construction sites or civil engineering works is contaminated with oil such as oil or heavy oil. If the soil contaminated with this oil is backfilled as it is, it will cause environmental pollution such as water pollution. In order to prevent this environmental pollution, it is necessary to clean up and backfill the soil contaminated with oil.

  As a method for purifying soil contaminated with oil, a biodegradation treatment method and a high thermal decomposition treatment method are generally performed. The biodegradation method is a method in which microorganisms are added to soil contaminated with oil, and organic compounds such as oil are decomposed by the added microorganisms. The high thermal decomposition treatment method is a method for removing oil in soil by incineration in a high-temperature kiln.

  Biodegradation methods can decompose low-molecular substances that are easily decomposed, but high-concentration ones are difficult to decompose, and it takes several months and a long time to decompose the oil contained in the soil. In addition, the high thermal decomposition treatment method requires a large-scale facility such as a rotary kiln to incinerate the oil contained in the soil, and also has a problem that it is necessary to treat the combustion exhaust gas, resulting in high treatment costs. .

In order to improve such a problem, as shown in Patent Document 1, after the soil contaminated with oil is slurried, bubbles are blown using a foam floating separator to float and separate the oil, and the separated oil Has been removed.
JP 2000-167533 A

  As shown in Patent Document 1, the method of slurrying oil-contaminated soil and blowing air bubbles to float and separate the oil component is very expensive due to the increase in the size of the actual scale purification equipment, as well as maintenance and inspection. However, it was not easy.

  The present invention improves such disadvantages, greatly increases the amount of oil contained in the soil regardless of the oil type, contamination form or contamination history, and efficiently recovers the oil separated from the soil particles. An object of the present invention is to provide an oil recovery device that can reduce the load of water treatment.

  The oil content recovery apparatus of this invention has a slurry agitation tank, a slurry circulation part, an oil recovery part, and a slurry supply part, and the slurry agitation tank comprises a tank body, a time trough, a slurry supply pipe, a slurry suction pipe, and a slurry outlet. The tank body is formed in a cylindrical shape, the upper part is open, and when the flow trough is provided concentrically with the tank body on the upper outer periphery of the tank body, the slurry supply pipe has a tip at which the slurry is ejected. The ejection part is formed in an approximately L shape, and is provided at the lower part of the side surface of the tank body. The slurry is ejected from the ejection part in the tangential direction of the inner peripheral surface of the tank body, and the slurry suction pipe is formed on the floor surface of the tank body. The slurry outlets are provided at a plurality of locations on the upper end of the tank body, and the slurry in the tank body is caused to flow out to the flow trough. A circulation pump and a fine bubble generator, wherein the suction port is connected to a slurry suction pipe of a slurry agitation tank, and a series of discharge ports are connected to a slurry supply pipe via a fine bubble generator, The recovery unit has an oil recovery pipe and an oil recovery plate. The oil recovery pipe has a top opening formed in a funnel shape and is disposed in the center of the tank body, and a slurry in which the upper end of the upper opening is provided in the tank body. Located at a position somewhat lower than the lower end of the outlet opening, the lower end penetrates the center of the bottom of the tank body and is fixed to the tank body, and the oil recovery plate runs along the diameter direction of the upper opening of the oil recovery pipe. The slurry supply unit is connected to the slurry supply pump and the discharge port of the slurry supply pump, and has a slurry supply pipe having an outlet at the upper part of the tank body. That.

  It is desirable that the slurry supply pipes of the slurry agitation tank are provided facing a plurality of locations at the lower part of the side surface of the tank body, and the slurry is ejected from the ejection portion in the tangential direction of the inner peripheral surface of the tank body and in the same direction.

  Also, the vicinity of the center of the water surface of the swirling flow in the tank body generated by the slurry jetted from the slurry supply pipe of the slurry agitating tank is somewhat lower than the lower end of the oil recovery plate, and the radial intermediate portion of the swirling flow is The discharge amounts of the slurry supply pump and the circulation pump are adjusted so that the outer periphery of the swirling flow contacts the lower end of the oil recovery plate and reaches the slurry outlet connected to the flow trough.

  Moreover, it is desirable that the oil recovery pipe has a height adjusting means for changing the height of the upper end portion.

  In this invention, while continuously supplying a slurry containing oil to the tank main body of the slurry agitation tank, the slurry in the tank main body is circulated to form a swirling flow, and oil and water are separated while being retained for a certain period of time. Since the oil is deposited and collected near the center of the water surface, the water content of the recovered oil can be reduced, and the oil can be recovered continuously.

  In addition, while circulating the slurry in the tank body with a circulation pump, fine bubbles are mixed in the circulating slurry by the fine bubble generator and the circulating slurry is tangent to the inner peripheral surface at the lower side of the tank body with the slurry supply pipe. Since the swirling flow is given to the slurry in the tank body by the slurry that is jetted in the same direction and in the same direction, fine bubbles can be reliably mixed into the slurry in the tank body, and the oil-water separation action is efficiently performed It can be carried out.

  Furthermore, since the circulating slurry gives a swirling flow to the slurry in the tank body, there is no need to provide a movable part in the tank body, the structure of the tank body can be simplified and maintenance and inspection can be easily performed. .

  Moreover, since the level of the center part and outer peripheral part of the water surface of the slurry swirling in the tank body can be adjusted by the discharge amounts of the slurry supply pump and the circulation pump, the oil recovery process can be performed with a simple operation. .

  1 and 2 are configuration diagrams of an oil content recovery apparatus according to the present invention, FIG. 1 is a side sectional view, and FIG. 2 is a plan view. As shown in the figure, the oil content recovery apparatus 1 includes a slurry agitation tank 2, a slurry circulation part 3, an oil recovery part 4, and a slurry supply part 5. The slurry agitation tank 2 includes a tank body 6, a trough 7 provided in the tank body 6, a slurry supply pipe 8, a slurry suction pipe 9, and a slurry outlet 10. The tank body 6 is formed in a cylindrical shape, the upper part is opened, and the outer peripheral surface is held by a bracket 11. The when-flow trough 7 is provided concentrically with the tank main body 6 on the upper outer peripheral portion of the tank main body 6, and has a discharge port 12 on the outer peripheral surface. The slurry supply pipes 8a and 8b are formed so that the tip jetting portion for jetting the slurry is substantially L-shaped, and is opposed to the two lower portions of the side surface of the tank main body 6, and the slurry is supplied from the jetting portion to the tank main body 6. It ejects in the tangential direction of the inner peripheral surface and in the same direction. The slurry suction pipe 9 is provided on the floor surface of the tank body 6. The slurry outlets 10 are provided at a plurality of, for example, two locations on the upper end of the tank body 6, and allow the slurry in the tank body 6 to flow out to the flow trough 7.

  The slurry circulation unit 3 includes a circulation pump 13 and a fine bubble generator 14. The circulation pump 13 has a suction port connected to the slurry suction pipe 9 of the slurry agitation tank 2 and branches the discharge port into at least two lines. One discharge port is connected to one slurry supply pipe 8a via a fine bubble generator 14. The other discharge port is directly connected to the other slurry supply pipe 8b. The oil recovery unit 4 includes an oil recovery pipe 15 and an oil recovery plate 16. The oil recovery pipe 15 has an upper end opening 17 formed in a funnel shape and is disposed at the center of the tank body 6, and the lower end passes through the center of the bottom of the tank body 6 and is fixed to the tank body 6. The oil recovery pipe 15 has a height adjusting screw 15a for adjusting the height of the upper end of the oil recovery pipe 15 at an intermediate portion. The oil recovery plate 16 is formed in a rectangular shape having a narrow width, is disposed along the diameter direction of the upper opening 17 of the oil recovery pipe 15, and a thin portion is fixed to the upper end of the upper opening 17. The lower end of the oil recovery plate 16, that is, the upper end of the upper opening 17 of the oil recovery pipe 16 is arranged at a position somewhat lower than the lower end of the opening of the slurry outlet 10 provided in the tank body 7. The slurry supply unit 5 includes a slurry supply pump 18 and a slurry supply pipe 19 connected to the discharge port of the slurry supply pump 18 and having an outlet at the top of the tank body 6.

  As shown in the block diagram of FIG. 3, the soil cleaning apparatus 20 using the oil recovery device 1 includes a soil sorting device 21 and a soil cleaning device 22 as a pre-process of the oil recovery device 1, and the oil recovery device 1 As a subsequent process, a solid-liquid separator 23, a gravity concentrator 24, and a filter 25 are provided. The soil sorting device 21 has a vibrating screen having a mesh width of 40 mm, for example, and mechanically separates the raw soil, which is contaminated soil, based on a particle size of 40 mm while applying vibration to the screen surface to prevent clogging. The soil cleaning device 22 includes a stirring device 26, a first classifying device 27, and a second classifying device 28. The stirring device 26 has a biaxial forced-kneading paddle mixer, and 0.1 to 0.4% of surfactant and 10 to 20% of water by weight with respect to the soil having a particle size of less than 40 mm sorted by the soil sorting device 21. And stirring for a certain time, for example, about 10 minutes. The first classifier 27 has a shower ring device 29 and a vibrating screen 30 having a mesh width of, for example, 2 mm. The particle size is measured by the vibrating screen 30 while spraying water from the shower ring device 29 to the soil stirred by the stirring device 26. Separation based on 2 mm. The second classifier 28 has an agitation tank 31 and a classifier 32, rinses the soil having a particle size of less than 2 mm classified by the first classifier 27, and soil having a particle size of 100 μm or more by the classifier 32; The slurry is separated into a slurry containing fine particles having a particle diameter of less than 100 μm.

  The solid-liquid separator 23 includes a cyclone 33, a dehydrator 34, a stirrer 35, and a centrifugal separator 36, and a soil of fine particles having a fixed particle size contained in a chiller that has been recovered by removing oil by the oil recovery device 1. Separate waste liquid. The gravity concentrator 24 is continuously provided with a plurality of concentration tanks 37 having a gentle slope at the bottom, depositing soil particles at the bottom, discharging the accumulated soil particles, and overflowing the separated water from surrounding overflow clogs. Recycle the separated water as treated water. The filter device 25 has, for example, a filter press, and removes moisture from the soil particles discharged from the gravity concentrator 24 to make a dehydrated cake.

  In this soil cleaning apparatus 1, when oil is collected from soil contaminated with oil excavated at civil engineering work or construction site, and the soil is purified, first, the raw material that is soil contaminated with oil excavated at civil engineering work, etc. The soil is separated into soil having a particle size of 40 mm or more and soil having a particle size of less than 40 mm by the vibrating screen of the soil sorting device 21. The separated soil having a particle size of 40 mm or more is recovered as purified soil, and the soil having a particle size of less than 40 mm is taken into the soil cleaning device 22. The soil having a particle size of less than 40 mm taken into the soil cleaning device 22 is supplied to the stirring device 26, and 0.1 to 0.4% of surfactant and 10 to 20% of cleaning water are added by weight ratio for a certain time, for example, Stir for about 10 minutes to remove the oil from the soil particles. At this time, as the surfactant to be added to water, limonene, preferably d-limonene and a nonionic surfactant are used. This d-limonene can be extracted from citrus peel and can prevent environmental pollution and the like.

  The soil stirred by adding washing water and a surfactant by the stirring device 26 is sent to the first classifying device 27 and subjected to the first-stage classification treatment. In the first classifying device 27, the soil sent to the vibrating screen 31 is stirred and rinsed with water while spraying water from the showering device 29 while preventing the clogging of the vibrating screen 30 and classifying with a particle size of 2 mm. To do. The classified soil particles having a particle diameter of 2 mm or more are collected as purified soil. The washing water having soil particles having a particle size of less than 2 mm is sent to the stirring tank 31 of the second classifier 28 and stirred for a certain period of time, for example, about 10 minutes to further rinse the soil particles. After rinsing with the stirring tank 31, washing water having soil particles having a particle diameter of less than 2 mm is sent to the classifier 32 to perform the second-stage classification process. Soil particles having a particle size of 100 μm or more classified by the second classification treatment are collected as purified soil.

  Then, the slurry containing soil particles having a particle size of less than 100 μm is sent to the oil component recovery device 1 by the slurry supply pump 18 of the oil recovery device 1 and supplied from the outlet of the slurry supply pipe 19 into the tank body 6 through the upper opening.

  When the slurry 40 supplied into the tank body 6 from the outlet of the slurry supply pipe 19 is stored above the level of the slurry supply pipes 8a and 8b provided at the lower side of the tank body 6, the circulation pump 13 and fine bubbles are generated. The apparatus 14 is driven, the slurry in the tank main body 6 is sucked from the slurry suction pipe 9 by the circulation pump 13, and the sucked slurry 40 is jetted into the slurry 40 in the tank main body 6 from the slurry supply pipes 8a and 8b. When this slurry 40 is ejected, the slurry 40 ejected from one of the slurry supply pipes 8a includes fine bubbles generated in the fine bubble generating device 14, and these fine bubbles are mixed into the slurry 40 in the tank body 6. To do. Moreover, since the slurry supply pipes 8a and 8b eject the slurry 40 in the tangential direction of the inner peripheral surface of the tank body 6 and in the same direction from the ejection portion formed in an approximately L shape, the slurry in the tank body 6 40 generates a swirling flow along the inner periphery of the tank body 6. Due to this swirling flow, the water surface of the slurry 40 in the tank body 6 is lowered at the center of the tank body 6 and forms a curved surface with a higher outer peripheral portion. The curved surface formed on the water surface of the slurry 40 differs depending on the strength of the swirling flow, that is, the amount of ejection per unit time ejected from the slurry supply pipes 8a and 8b. Therefore, the supply amount of the slurry 40 supplied into the tank body 6 from the slurry supply pump 18 via the slurry supply pipe 19 is adjusted to a constant flow rate, and the discharge amount from the circulation pump 13 is controlled to control the slurry supply pipe 8a, The ejection amount of the slurry 40 ejected into the tank body 6 from 8b is adjusted. When the supply amount of the slurry 40 to the tank main body 6, the circulation amount in the tank main body 6 and the discharge amount to the flow trough 7 reach a steady state, the oil recovery plate 16 is rotated and the middle of the oil recovery pipe 15 is rotated. The height of the upper edge position of the oil recovery pipe 15 is varied using the height adjusting screw 15 a provided in the section so that the upper edge of the oil recovery pipe 15 is slightly higher than the water level at the center of the tank body 6. Adjust to. By adjusting the height of the upper edge of the oil recovery pipe 15, the lower end portion of the oil recovery plate 16 attached to the oil recovery pipe 15 is higher than the water surface in the vicinity of the central portion of the swirl flow, and is intermediate in the radial direction of the swirl flow. It is almost in contact with the water surface. Further, when the outer periphery of the swirl flow reaches the slurry outlet 10 connected to the flow trough 7, the slurry 40 in the tank body 6 flows out from the slurry outlet 10 to the flow trough 7 and is the water surface of the slurry 40. The curved surface is maintained and the supply amount and the outflow amount of the slurry 40 supplied to the tank body 6 are made equal.

The slurry 40 swirling in the tank body 6 contains the fine bubbles generated in the fine bubble generator 14, so that the slurry 40 supplied from the slurry supply pipe 19 stays in the tank body 6. While swirling, oil and water are separated by fine bubbles. For example, when the volume of the tank body 6 is 10 m ³ and the supply amount supplied to the tank body 6 and the outflow amount flowing out from the tank body 6 are 1 m ³ , the supplied slurry stays in the tank body 6 for 10 minutes, and the oil water Undergoes separation. The oil separated by this oil / water separation action floats on the water surface of the slurry 40 while swirling. The oil component that has floated is inhibited from swirling by the oil recovery plate 16 provided at the upper end of the oil recovery pipe 15, and gathers and accumulates along the oil recovery plate 16 in the central portion having a low water level. As shown in FIG. 1, when the oil component 41 accumulates up to the upper end of the upper opening 17 of the oil recovery pipe 15, it continuously flows into the oil recovery pipe 15 from the upper opening 17. The oil 41 that has flowed into the oil recovery pipe 15 is recovered by the oil recovery tank 42.

  In this way, while continuously supplying the slurry 40 containing oil to the tank body 6, the slurry 40 in the tank body 30 is circulated to form a swirl flow, and the oil water is separated and accumulated while being retained for a certain period of time. Therefore, the water content of the recovered oil 41 can be reduced, and the oil 41 can be recovered continuously.

  Further, while circulating the slurry 40 in the tank body 30 with the circulation pump 13, the microbubbles are mixed in the circulating slurry 40 by the microbubble generator 14 and the circulated slurry 40 is added to the tank body 6 by the slurry supply pipes 8 a and 8 b. Since the swirling flow is given to the slurry 40 in the tank body 6 by the circulating slurry 40, the fine bubbles are surely mixed into the slurry 40 in the tank body 30. Therefore, the oil / water separation action can be performed efficiently.

  Furthermore, since the swirling flow is given to the slurry 40 in the tank body 6 by the circulating slurry 40, it is not necessary to provide a movable part in the tank body 6, and the structure of the tank body 6 can be simplified.

  On the other hand, the slurry 40 that has flowed out into the flow trough 7 is sent from the discharge port 12 to the cyclone 33 of the solid-liquid separator 23, and the soil particles are separated by the swirling motion by the cyclone 33. The separated soil particles are sent to a dehydrator 34 and separated into soil particles having a particle size of 45 μm or more and soil particles having a particle size of less than 45 μm by a dehydration screen. The separated soil particles having a particle size of 45 μm or more are collected as purified soil. The separated soil particles having a particle size of less than 45 μm are sent to the cyclone 33 again. The slurry that has overflowed due to the separation of the soil particles by the cyclone 33 is fed into a stirring device 35 having an agitator, and is slowly stirred to prevent the sedimentation of the soil particles. The stirred chiller is sent to the centrifuge 36 to separate the soil particles and the waste liquid, and the separated soil particles are recovered as concentrated sludge soil. Further, the waste liquid separated by the centrifugal separator 36 is sent to the concentration tank 37 of the gravity concentrator 24 and separated into a thick mud and separated water. The separated mud is sent to the filtration device 25 to remove water and form a dehydrated cake, which is collected as concentrated sludge soil. Further, the separated water that has separated and overflowed from the concentration tank 37 is sent to the stirring device 26 or the showering device 29 of the soil cleaning device 20 as treated water and reused.

  In the above description, the case where two sets of slurry supply pipes 8 a and 8 b are provided in the tank body 6 has been described, but one or more sets of slurry supply pipes 8 may be provided according to the outer diameter of the tank body 6.

It is side surface sectional drawing which shows the structure of the oil-component collection | recovery apparatus of this invention. It is a top view which shows the structure of an oil-component collection | recovery apparatus. It is a block diagram of a soil washing processing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Oil content collection apparatus, 2; Slurry stirring tank, 3; Slurry circulation part, 4; Oil recovery part,
5; Slurry supply unit, 6; Tank body, 7; When trough, 8; Slurry supply pipe,
9; slurry suction pipe, 10; slurry outlet, 11; bracket, 12; outlet,
13; Circulation pump, 14; Microbubble generator, 15; Oil recovery pipe,
16; oil recovery plate, 17; upper end opening, 18; slurry supply pump,
19; Slurry supply pipe, 20; Soil washing treatment device, 21; Soil sorting device,
22; soil washing device; 23; solid-liquid separation device; 24; gravity concentration device; 25;
40; slurry, 41; oil content, 42; oil recovery tank.

Claims (4)

A slurry agitation tank, a slurry circulation part, an oil recovery part and a slurry supply part,
The slurry agitation tank has a tank body, a when-flow trough, a slurry supply pipe, a slurry suction pipe, and a slurry outlet, the tank body is formed in a cylindrical shape, an upper part is opened, and the when-flow trough is A slurry body is provided concentrically with the tank body at the upper outer periphery of the tank body. The slurry supply pipe is formed with a substantially L-shaped ejection portion for ejecting slurry, and is provided at a lower portion of the side surface of the tank body. From the ejection part in a tangential direction of the inner peripheral surface of the tank body, the slurry suction pipe is provided on the floor surface of the tank body, and the slurry outlet is provided at a plurality of locations on the upper end of the tank body. Provided, and when the slurry in the tank body flows out to the flow trough,
The slurry circulation unit includes a circulation pump and a fine bubble generator, and the circulation pump has a suction port connected to a slurry suction pipe of the slurry agitation tank, and a series of discharge ports is connected to the fine bubble generator. Connected to the slurry supply pipe,
The oil recovery section includes an oil recovery pipe and an oil recovery plate, and the oil recovery pipe has an upper end opening formed in a funnel shape and is disposed at the center of the tank body, and the upper end of the upper opening is the tank. It is arranged at a position somewhat lower than the lower end of the opening of the slurry outlet provided in the main body, the lower end passes through the center of the bottom of the tank main body and is fixed to the tank main body, and the oil recovery plate is an upper part of the oil recovery pipe. Fixed to the upper end of the upper opening along the diameter direction of the opening,
The said slurry supply part is connected to the discharge port of a slurry supply pump and a slurry supply pump, and has the slurry supply piping which has an outflow port in the upper part of the said tank main body, The oil-component collection | recovery apparatus characterized by the above-mentioned.   The slurry supply pipe of the slurry agitation tank is provided to face a plurality of locations at the lower part of the side surface of the tank body, and the slurry is ejected from the ejection part in the tangential direction of the inner peripheral surface of the tank body and in the same direction. The oil content recovery apparatus according to 1.   The vicinity of the center of the water surface of the swirling flow in the tank body generated by the slurry ejected from the slurry supply pipe of the slurry agitating tank is somewhat lower than the lower end of the oil recovery plate, and the intermediate portion in the radial direction of the swirling flow The discharge amount of the slurry supply pump and the circulation pump is adjusted so that the outer peripheral portion of the swirling flow reaches the slurry outlet connected to the flow trough when the oil comes into contact with the lower end of the oil recovery plate. The oil content recovery apparatus according to 1 or 2. The oil recovery apparatus according to any one of claims 1 to 3, wherein the oil recovery pipe has a height adjusting means for changing a height of an upper end portion.

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