JP6004562B2 - Oil recovery equipment for crude oil sludge - Google Patents

Description

  The present invention relates to an apparatus for recovering oil in crude oil sludge accumulated at the bottom of a crude oil tank, for example.

  Oil contained in crude oil sludge accumulated in a crude oil tank or the like is usually about 30 to 80% by weight, and there is a great need for oil recovery. Examples of the crude sludge treatment method and treatment technique include COW (Crude Oil Washing) method, hot water washing method, chemical treatment method, manual method, and centrifugal separation method.

  In the COW method, crude oil is heated to about 60 ° C., pressurized, sludge accumulated at the bottom of the tank by an injection nozzle is pulverized, dissolved, and transferred to another tank. Although crude sludge can be processed in a short period of time and has a lot of results, sludge is deposited again at the destination. For this reason, it can be said that it is a prescription for turning crude oil sludge. The COW method is a method of forcibly stirring uprooted sludge to make it temporarily fluid and recovering it to another tank, so there is a merit that sludge is not carried out of the tank. The problem has occurred and the problem is not essentially solved. Japanese Utility Model Laid-Open No. 6-81649 discloses a liquid ejecting apparatus used in the COW method.

  The hot water washing method is a method that dissolves and floats crude sludge with hot water, and is a relatively safe treatment method, but it requires a large amount of hot water, so it is expensive, and oil that does not dissolve in hot water cannot be recovered. There are various problems such as emulsion generated by agitation and treatment of a large amount of waste water, and it is not so often used recently.

  The chemical treatment method uses a chemical that dissolves sludge, but for reasons such as requiring heating and stirring operations, limited dissolution effects, and increased costs. This is rarely done recently.

  The manual method has been practiced for a long time by a method in which an operator enters a tank and discharges it outside the tank with a manual or automatic excavator, and there are many places where it is still practiced. There are health, safety and global environment conservation (HSE) in recent years, especially safety issues. There is also a problem that the oil content of the discharged crude oil sludge is not recovered.

  Any of the above methods has a serious problem in terms of recovery of the oil content in the crude oil sludge, and is not an effective method. In this respect, the centrifugal separation method is a promising method in that, for example, a decanter type three-phase (solid matter, water, oil content) separator is used, and an oil content with little solid content or moisture content can be recovered. SEPTEMBER 2009 / STORAGE TERMINALS; pages 27-30 disclose the use of a decanter-type three-phase separator to recover oil from crude sludge. JP-A-2004-243300 discloses a method for treating oil-water mixed sludge accumulated in a crude oil tank or the like, after separating the sludge into a solid content and a liquid content with a centrifugal separator, A method is disclosed in which a polymer flocculant is added to coagulate and precipitate oil suspended in a liquid in a suspended state.

Japanese Utility Model Publication No. 6-81649 JP-A-2004-243300 (Claim 1)

STORAGE TERMINALS; September 2009, pp. 27-30

However, the centrifugal separation method using a decanter type three-phase separator has a processing speed of about 10 kl / hour even with a large sized separator, and it takes time to process a large amount (usually 2000 m ³ or more) accumulated in a large tank. Take it. In addition, it is difficult to feed from a crude oil tank to a centrifuge, and in many cases, it is necessary to feed more than twice the amount of sludge in order to stir and mix with fresh crude oil. In addition, pretreatment such as heating and injection of an emulsion breaker is necessary, and there is a problem that it is difficult to recover and oil is difficult to recover with a stable quality. In addition, it is difficult to completely separate solid sludge, oil, and moisture, and there is a problem that the recovered oil contains solids and, in many cases, at least about 2% of water. For this reason, it is a simple method that does not require pretreatment such as dilution of crude oil sludge and injection of emulsion breaker, and can be directly processed, and the crude oil sludge with little water contamination in the recovered oil Development of an apparatus for carrying out an oil recovery method has been desired.

  Conventionally, the vacuum evaporation tank is used for drying waste containing a large amount of water, such as waste food or excess sludge, or for obtaining dry food. Further, a decompression process such as distillation of petroleum under reduced pressure using a vacuum distillation apparatus or the like is also known. Both are aimed at efficient evaporation with reduced boiling points of water and oil under reduced pressure. However, there is no known vacuum evaporation tank for the purpose of breaking the emulsion in the crude oil sludge, and there is no known oil recovery apparatus for the crude oil sludge having two separators for the purpose of collecting the oil in the subsequent stage.

  Accordingly, an object of the present invention is to provide an oil content recovery device for crude oil sludge that directly processes crude oil sludge and that hardly contains water in the recovered oil content.

  In such a situation, the present inventor has intensively studied, and as a result, the crude oil sludge contains a water-in-oil emulsion phase, so that water is inevitably mixed in the recovered oil in the conventional centrifugal separation method. In addition, the water-in-oil emulsion in crude oil sludge can be easily broken by vacuum evaporation using a vacuum evaporation tank, and the evaporation substance and evaporation residue obtained from the vacuum evaporation tank can be converted into oil that does not contain moisture by a simple separation device. The inventors have found that each can be recovered, and have completed the present invention.

  That is, the present invention separates a crude oil sludge into a vacuum evaporation tank for vacuum evaporation, a condenser for cooling the evaporated substance obtained in the vacuum evaporation tank, and a condensate obtained from the condenser into light oil and water. An apparatus for recovering oil in crude oil sludge comprising a first separator and a pipe having an evaporation residue removal valve and one end connected to the vacuum evaporation tank is provided.

  According to the apparatus of the present invention, crude oil sludge is vacuum evaporated in a vacuum evaporation tank, so that a strong water-in-oil emulsion can be broken without using chemicals, light oil content from the evaporated substance, heavy oil from the evaporation residue Each oil can be recovered efficiently. In addition, since these recovered oil components hardly contain moisture, they can be recovered by blending with crude oil or the like as they are, and the environmental load can be greatly reduced. In addition, since the oil recovery rate is high, the needs for oil recovery can be satisfied with the recent rise in crude oil prices. Further, the heavy oil can be recovered and used together with solids or separated into heavy oil and solids and used individually as industrial fuel.

It is a device that recovers oil from crude sludge.

  In the present invention, as the crude oil sludge, sludge accumulated at the bottom of the crude oil tank outdoors, sludge accumulated at the bottom of the crude oil tank of the crude oil tanker, crude oil sludge exposed to the outdoors or crude oil sludge drifting the ocean, or after drifting the ocean Crude oil sludge berthed. Examples of the sludge accumulated on the bottom of an outdoor crude oil tank include those accumulated at a thickness of 500 to 2000 mm on the bottom of the tank during regular inspection after being used for a long period of 5 to 10 years, for example. Crude oil sludge exposed to the open air is discharged into deserts that are larger than crude oil tanks by the conventional manual method, and is often found in oil producing countries such as the Caspian Sea coast and the Middle East. The crude oil sludge drifting in the ocean or the crude oil sludge docked after drifting includes, for example, an oily pollutant in which crude oil that has flowed into or out of the ocean due to an undersea oil field accident or a tanker accident and seawater are mixed. Such an oil pollutant is generally an emulsion produced by mixing crude oil and seawater, so it is an environmental pollutant called crude oil mousse. Compared with crude oil sludge accumulated in a crude oil tank, Although it has the same or similar composition, it has a high oil content and a low solid content.

  Crude oil sludge contains asphaltenes, coke-like substances, oil and water. The oil content contained in the crude oil sludge is not particularly limited, and is usually 20 to 80% by weight. Crude oil sludge may be diluted with crude oil. A coke-like substance is also called a coke precursor, and is a solid substance in which asphaltenes are condensed. Moreover, as a water | moisture content contained in crude oil sludge, it is 10 to 30 weight% normally. Other substances contained in the crude oil sludge include those in which the wax content in the crude oil crystallizes and settles due to a decrease in temperature or the like, or inorganic substances such as iron and sand. In crude oil sludge, the amount of solids including asphaltene and coke is the remainder excluding oil and moisture.

  Asphaltenes are a general term for petroleum components that are insoluble in n-hexane and soluble in toluene, and are solid components in crude oil alone. Asphaltenes include those that settle as solid particles and become sludge, and those that form an emulsion together with heavy components such as resin and moisture to settle and sludge.

  Asphaltenes that settle as solid particles are those in which crude asphaltene particles are covered with resin (heavy oil) and exist stably in a colloidal form, mixed with different oil types such as light oil. In other cases, the resin is detached from the periphery of the asphaltenes due to a thermal history and settled as solid particles.

  On the other hand, as described above, crude oil sludge contains about 10 to 30% by weight of water regardless of the type of crude oil. For this reason, asphaltenes form a water-in-oil (W / O) emulsion that is stable and does not phase-separate with heavy components such as resins and moisture. This water-in-oil (W / O) emulsion is stable and does not phase separate because the film formed around the water droplets is stable. This is because the asphaltene is three-dimensionally cross-linked and the resin is solvated. This emulsion phase is extremely stable and is the most troublesome component in treating crude oil sludge and does not disappear by centrifugation or the like.

  As described above, crude oil sludge is complexly mixed with asphaltene particles, coke-like substances, water-in-oil emulsions, wax crystallized substances, and the like, and interacts such as aggregation, emulsion, and gelation. In addition, although crude oil sludge is deposited at the bottom of the tank, for example, it is mixed with oil, so what method should be used to separate the crude oil sludge from the oil when discharging it to the outside of the tank? However, the oil and sludge are mixed in order to provide fluidity, and the oil is generally contained in a large amount such as 80% by weight at maximum. For reference, the properties of crude oil sludge accumulated in the crude oil tanks of each company are shown in Table 1. In Table 1, the heptane-insoluble fraction is soluble in the fraction (oil) up to the resin, and asphaltene is insoluble. The benzene insoluble matter is soluble up to asphaltenes, and the insoluble matter is mud moisture, minerals and coke-like substances. The coke-like substance is a main component of benzene insoluble matter. It should be noted that the toluene-insoluble component and the benzene-insoluble component are considered to be substantially the same substance because both solvents have substantially the same solubility. The oil content is a calculated value, which is 100- (heptane-insoluble content)-(water content), and the asphaltene is a calculated value, which is (heptane-insoluble content)-(benzene insoluble content).

  Next, an example of the oil recovery device in the crude oil sludge of the present invention will be described with reference to FIG. An oil content recovery device (hereinafter also simply referred to as “oil content recovery device”) 10 in crude oil sludge includes a vacuum evaporation tank 1 that vacuum-evaporates crude oil sludge, and a condenser that cools the evaporated material obtained in the vacuum evaporation tank 1. 2, a first separator 3 that separates the condensate obtained from the condenser 2 into light oil and water, a pipe having an evaporation residue take-off valve 17, and one end connected to the vacuum evaporation tank (an evaporation residue inflow pipe) ) 18 and a second separator 4 for separating the evaporation residue obtained in the vacuum evaporation tank 1 into a heavy oil and a solid residue. The oil content recovery device 10 may be either a fixed type or a portable type.

  The vacuum evaporation tank 1 has heating means for heating the crude oil sludge in the vacuum evaporation tank 1 to a constant temperature. Examples of such heating means include steam and an electric heater. In this example, the vacuum evaporation tank 1 has an outer heating space (jacket) 12, and the steam 9 generated in the boiler is heated through the steam pipe 91. The front end of the steam pipe 91 on the steam supply source side is a connection port of a known coupling structure that takes in external steam. In addition, when the oil content recovery apparatus 10 is a fixed type, the connection port of a coupling structure is unnecessary and the front-end | tip of the steam piping 91 is directly connected to a boiler. The steam pressure is preferably about 0.1 to 0.3 MPa, and the steam temperature is preferably slightly higher than the saturation temperature. As the boiler fuel, if each of the solid and heavy oil mixture obtained from the second separator 4 of the oil content recovery apparatus 10 of the present invention or the separated heavy oil and solid material is used separately, The operating cost can be reduced.

  The vacuum evaporation tank 1 has a pressure reducing means such as a vacuum pump 5 for reducing the pressure in the tank. The vacuum pump 5 can use a well-known thing, and may be either a water seal type or a dry type. The decompression means is typically a vacuum pump, but is not limited thereto, and for example, an ejector can be used. The ejector uses a compressed gas such as pressurized water or steam as a driving fluid to pass through a nozzle and reduce the pressure by suction. Further, an inlet valve 16 of the vacuum evaporation tank 1 for reducing the pressure reduction system, an evaporation residue takeout valve 17, a drain valve 34 of the first separator 3, and a light oil takeout valve 35 of the first separator 3 are provided. . When the vacuum evaporation tank 1 is decompressed, these valves are closed. That is, the decompression system is up to the vacuum evaporation tank 1, the condenser 4 and the first separator 3.

  The vacuum evaporation tank 1 having the stirring blades 11 is preferable in that the crude oil sludge can be stirred uniformly. The stirring speed (rotational speed) of the stirring blade 11 is not particularly limited, but may be about 2 to 30 rotations / minute. With such a stirring speed, the evaporation of the evaporating substance in the crude oil sludge can be sufficiently promoted. In addition, the shaft (shaft) for rotating the stirring blades may have a hollow structure to increase the heat transfer area through steam through the space. By passing steam through the outer heating space or the like, the temperature of the crude oil sludge can be made more uniform.

  The oil recovery device 10 includes a condenser 2 that cools the evaporated substance obtained in the vacuum evaporation tank 1. A known condenser can be used as the condenser 2. It does not restrict | limit especially as a refrigerant | coolant for cooling of the condenser 2, Well-known refrigerant | coolants other than water, such as seawater and industrial water, are mentioned. The condenser 2 is connected with an evaporative substance outflow pipe 22 and a condensate outflow pipe 23. That is, the evaporated substance obtained in the vacuum evaporation tank 1 flows into the condenser 2 through the evaporated substance outflow pipe 22, and the condensed substance condensed by the condenser 2 is first separated through the condensed substance outflow pipe 23. Sent to vessel 3. Further, when the oil content recovery device 10 is portable, the tip on the refrigerant supply source side of the pipe 21 through which the cooling refrigerant passes is a connection port of a known coupling structure that takes in an external refrigerant. In addition, when the oil content collection apparatus 10 is a fixed type, the connection port of a coupling structure is unnecessary and the front-end | tip of the piping 21 is directly connected to a refrigerant supply source.

  The oil content recovery apparatus 10 includes a first separator 3 that separates the condensed material obtained from the condenser 2 into light oil and water. The first separator 3 is preferably a gravity type oil / water separator in that the condensed substance can be easily and reliably separated into light oil and water. The gravity type oil-water separator is divided into two chambers by a baffle plate 31 having a predetermined height lower than the internal height, for example, and a condensate inflow pipe 23 and a moisture discharge pipe 36 are provided in one chamber 32. The other chamber can be used with a light oil outflow pipe 37 connected thereto. The condensed material 321 flows into the one chamber 32 through the condensed material inflow pipe 23. The condensate 321 flowing into the chamber 32 is a mixture of light oil and water, does not become an emulsion, and is completely separated up and down. A light oil component having a specific gravity lower than that of water, which is statically separated in one chamber 32, flows into the other chamber 33 as it overflows from the chamber 32. For this reason, the light oil collected in the other chamber 33 is hardly mixed with moisture. The separated water remaining in one chamber 32 is drained by opening the drain valve 34. The first separator 3 may have a one-chamber structure without a baffle plate. When the first separator 3 is a single chamber, a light oil content recovery pipe or the like may be installed in the vicinity of the center of the light oil content separator 3 in the height direction.

  The first separator 3 is provided with a liquid level gauge (not shown) for observing the interface level of the oil / water interface. By observing the liquid level gauge of the first separator 3, it can be known that the evaporation of moisture in the crude oil sludge has stopped. A pipe 38 having one end connected to the vacuum pump 5 is connected to the gas phase portion of the first separator 3. Further, a pipe 52 provided with a decompression release valve 51 is connected to the pipe 38. The other end of the pipe 52 is open to the atmosphere. Thereby, by opening the decompression release valve 51, the decompressed system can be brought to atmospheric pressure.

  The oil recovery device 10 includes a second separator 4 that separates the evaporation residue obtained in the vacuum evaporation tank 1 into a heavy oil and a solid residue. That is, the second separator 4 and the vacuum evaporation tank 1 are connected by the evaporation residue inflow pipe 18. The second separator 4 is preferably a gravity type solid-liquid separator in that the fluidized evaporation residue can be easily separated into a solid content and a heavy oil content. The second separator 4 is divided into three chambers whose height decreases from the upstream side toward the downstream side by a plurality of baffle plates 41 and 42 having different inner heights than the inner height. The evaporation residue inflow pipe 18 and the solid content discharge pipe 48 are connected to the chamber 43 on the side, and the heavy oil outlet pipe 49 is connected to the chamber 45 on the most downstream side. The evaporation residue 431 flows into the chamber 43 on the most upstream side of the second separator 4 through the evaporation residue inflow pipe 18 due to gravity drop. The evaporation residue that has flowed into the chamber 43 is a mixture of heavy oil and solids, and has no moisture, so there is no emulsion and it is separated into upper and lower parts. The heavy oil component that has been allowed to stand and separate in the chamber 43 and a part of the solid content flow into the adjacent chamber 44 as it overflows from the chamber 43. In addition, the heavy oil that has been allowed to stand and separate in the chamber 44 flows into the adjacent chamber 45 as it overflows from the chamber 44. The heavy oil recovered in the most downstream chamber 45 contains almost no moisture. The separated solid content remaining in the chamber 43 is discharged by opening the discharge valve 86 to be disposed of as waste.

  The second separator 4 is not limited to the above three rooms, and may be one room, two rooms, or four or more rooms. When the second separator 4 is one chamber, a heavy oil recovery pipe or the like may be installed in the vicinity of the center of the second separator 4 in the height direction. When the second separator 4 has two chambers, the interior is divided into two chambers by a baffle plate having a predetermined height lower than the internal height, and one chamber has an evaporation residue inflow pipe and a solid content discharge pipe. However, the heavy oil outlet pipe is connected to the other chamber.

  In the oil recovery device 10, the installation of the second separator 4 can be omitted. That is, the vacuum evaporation tank 1 may be provided with an evaporation residue take-out valve 17 and an evaporation residue inflow pipe 18 having one end connected to the vacuum evaporation tank 1. Thereby, the other end of the evaporation residue inflow pipe 18 becomes a free end and can be connected to a recovery container (not shown) or a crude oil tank for recovering the evaporation residue obtained in the vacuum evaporation tank 1. For this reason, in the case of crude sludge having a small solid content such as crude mousse, the evaporation residue in the vacuum evaporation tank can be taken out of the vacuum evaporation tank as it is. Since crude mousse has a high oil content and a low solid content, it is efficient to recover the solid content and heavy oil without separating them. For example, if the recovered heavy oil containing a small amount of solids is returned to the crude oil tank, the recovery efficiency is increased.

  The oil content recovery apparatus 10 includes a crude oil sludge supply pipe 17 that introduces crude oil sludge into a vacuum evaporation tank. When the oil content recovery device 10 is portable, the supply-side tip of the crude oil sludge supply pipe 17 through which the crude oil sludge passes is a connection port of a known coupling structure that takes in the crude oil sludge. When the oil content recovery device 10 is fixed, the crude oil sludge supply pipe 17 is connected to the crude oil tank or the crude oil sludge storage tank 6 via the raw material pump 63. For example, crude oil sludge storage tank 6 collects crude oil sludge 61 deposited on land or in a ship's crude oil tank, crude oil sludge left in the field, and oily pollutants (crude oil mousse) drifting or landing in the ocean. The raw material tank transferred to The crude oil tank or the crude oil sludge storage tank 6 has heating means 62 for heating the crude oil sludge 61. Thereby, the fluidity | liquidity of the heated crude oil sludge 61 increases and automatic conveyance with the raw material pump 63 can be performed.

  Next, an example of a method for recovering oil in the crude oil sludge using the oil recovery device 10 will be described. First, crude oil sludge 61 is introduced into the vacuum evaporation tank 1. The method of introducing the crude oil sludge 61 into the vacuum evaporation tank 1 is not particularly limited, but the crude oil sludge 61 heated by the heater 62 and having fluidity may be automatically conveyed by the screw pump 63 or the like.

Next, the crude oil sludge in the vacuum evaporation tank 1 is heated and stirred under vacuum to evaporate the light oil and water in the crude oil sludge 61, and the evaporated substance is cooled to separate into light oil and water. Perform the process. In the vacuum evaporation process, the inlet valve 16 and the distillation residue take-out valve 17 of the vacuum evaporation tank 1 are closed, the condenser 2 and the first separator 3 are sealed in the system, and the vacuum pump 5 is operated to operate the system in the system. Is reduced pressure. Moreover, the crude oil sludge 61 is heated by flowing steam into the outer heating space 12 of the vacuum evaporation tank 1 and, if necessary, the outer heating space of the shaft of the stirring blade. In FIG. 1, symbol E ₁ indicates the exhaust of the vacuum pump.

  In the vacuum evaporation process, the heating and vacuum conditions are such that the evaporated substance of the crude oil sludge 61 contains moisture and a part of oil. Some oil components are light oil components that evaporate with the evaporation of moisture. The light oil has a boiling point of up to 250 ° C. under atmospheric pressure and particularly up to 200 ° C. under atmospheric pressure. Specific examples of the heating and vacuum conditions include a heating temperature of 70 to 150 ° C., preferably 70 to 130 ° C., and a degree of vacuum (gauge pressure) of −80 to −100 KPa, preferably a degree of vacuum (gauge pressure) of −90 to − 100 KPa. Under such heating and vacuum conditions, water in the crude oil sludge can be surely evaporated and the emulsion can be extinguished. Also, the light oil other than water was entrained as an evaporating substance because the water was surely evaporated, and the water and light oil that did not form an emulsion were easily and reliably placed by means such as standing after condensation. This is because they can be separated. On the other hand, evaporating only the moisture from the crude oil sludge requires a delicate operation, and even if only the moisture is evaporated, it is not easy to remove a trace amount of light oil that is inevitably mixed.

  In the vacuum evaporation step, the amount of light oil to be evaporated differs depending on the amount of light oil contained in the crude oil sludge and cannot be determined unconditionally, but is generally 5% by weight or more, preferably 10% by weight to the oil content of the crude oil sludge. 50% by weight. If the amount of the light oil to be evaporated is too small, the evaporation of water becomes insufficient and the emulsion may not be completely extinguished. On the other hand, when the amount is too large, the heating temperature and the degree of vacuum are increased more than necessary, which is not efficient. On the other hand, if the lower limit value of the amount of light oil to be evaporated is the above value, the water is sufficiently evaporated and the emulsion can be completely extinguished.

  Stirring of the crude oil sludge in the vacuum evaporation process is performed in order to uniformly heat and promote evaporation of the evaporated substance in the crude oil sludge. The stirring speed (rotation speed) is not particularly limited, but may be about 2 rotations / minute to 30 rotations / minute. With such a stirring speed, the evaporation of the evaporating substance in the crude oil sludge can be sufficiently promoted.

  In the vacuum evaporation process, with the heating and decompression of the vacuum evaporation tank 1, evaporation of light oil such as gasoline in the crude oil sludge starts, and the water forming the emulsion also evaporates. The emulsion disappears due to the evaporation of moisture.

The evaporated substance obtained by vacuum distillation is cooled through the condenser 2. The condensed material condensed by the condenser 2 is separated into light oil and water by static separation in the first separator 3, and the light oil is recovered. That is, the condensed material 321 is caused to flow into the chamber 32 through the condensed material outflow pipe 23. The condensate 321 flowing into the chamber 32 is a mixture of light oil and water, does not become an emulsion, and is completely separated up and down. A light oil component having a specific gravity lighter than water, which is statically separated in one chamber 32, flows into the other chamber 33 by overflowing the chamber 32. For this reason, the light oil collected in the other chamber 33 is hardly mixed with water, and is usually 0.5% by weight or less, particularly 0.3% by weight or less, and further 0.1% by weight or less. It is. The light oil component 322 accumulated in the chamber 33 is recovered from the light oil component outflow pipe 37 (reference symbol P _{1 in} FIG. ₁ ). The separated water remaining in one chamber 32 may be drained by opening the drain valve 34 (symbol P _{2 in} FIG. 1).

  The vacuum evaporation process is terminated when the evaporation of water in the crude oil sludge substantially stops and the operation of the vacuum pump 5 is stopped. It can be determined by observing the liquid level gauge of the first separator 3 whether or not the evaporation of water in the crude oil sludge has stopped. That is, when the oil-water interface (water level) of the liquid level gauge does not change with time, it can be determined that the evaporation of moisture has stopped. Further, by observing the rising tendency of the temperature in the vacuum evaporation tank 1, it can be determined that the evaporation of moisture has stopped. That is, in the vicinity of the end of the vacuum evaporation step, the evaporation substance in the vacuum evaporation tank 1 decreases, and the heating proceeds, so that the internal temperature of the vacuum evaporation tank 1 rises.

  After the operation of the vacuum pump 5 is stopped, the decompression release valve 51 is further opened to send the atmosphere into the system so that the system is at atmospheric pressure. The evaporation residue in the vacuum evaporation tank 1 consists of a solid content and heavy oil content containing asphaltenes and coke-like substances, and the emulsion in the evaporation residue disappears and contains almost no water. The heavy oil is an oil that is heavier than the light oil in the evaporated substance. Further, the evaporation residue after the vacuum evaporation step is high temperature and has sufficient fluidity.

  Next, the evaporation residue in the vacuum evaporation tank 1 is taken out of the vacuum evaporation tank 1, and preferably, the extracted evaporation residue is separated into a heavy oil component and a solid residue. In order to take out the evaporation residue in the vacuum evaporation tank 1 to the outside of the vacuum evaporation tank 1, the valve 17 installed in the pipe 18 connecting the vacuum evaporation tank 1 and the second separator 4 may be opened. Thereby, the evaporation residue in the vacuum evaporation tank 1 flows into the 2nd separator 4 by gravity fall. That is, the evaporation residue in the vacuum evaporation tank 1 is taken out of the vacuum evaporation tank in a fluidized state.

The evaporation residue 431 flows into the uppermost stream side chamber 43 of the second separator 4. The evaporation residue that has flowed into the chamber 43 is a mixture of heavy oil and solids, and since there is no moisture, there is no emulsion and it is completely separated vertically. The heavy oil component and a part of the solid content that are statically separated in the chamber 43 flow into the adjacent chamber 44 by overflowing from the chamber 43. In addition, heavy oil components that have been stationary and separated in the chambers 44 flow into the adjacent chambers 45 as they overflow from the chambers 44. The heavy oil recovered in the most downstream chamber 45 is hardly mixed with water, and is usually 1.5% by weight or less, particularly 1.0% by weight or less, and further 0.5% by weight or less. It is. The heavy oil collected in the chamber 45 is recovered from the heavy oil outflow pipe 49 (reference numeral P _{3 in} FIG. 1). Note that the separated solid content remaining in the chamber 43 is discharged by opening the discharge valve 46 (reference symbol P _{4 in} FIG. 1), and is recovered, for example, as fuel. If it is required that the remaining amount of solids in the heavy oil is very small, the heavy oil and solids mixture can be further separated by a filter or centrifuge using a metal filter. Also good.

  In the oil recovery method using the oil recovery device of the present invention, the recovery rate of the total oil from the crude oil sludge, that is, the total oil with respect to the oil in the raw material charged in the vacuum evaporation tank is almost 100%. Since there is an oil that cannot be collected that is sucked by the pump, it can be collected at about 98%. The water content in the total oil, which is the sum of the recovered light oil and heavy oil, is usually less than 1.0% by weight, preferably 0.5% by weight or less. The recovered oil may be recovered as a mixture of light oil and heavy oil, or the heavy oil may be recovered as a mixture together with the solid. A mixture of heavy oil and solids, or separated heavy oil and solids can be used as industrial fuels. With such an oil content recovery method, no chemicals are used, so that processing such as chemical recovery is unnecessary, and the environmental burden can be greatly reduced. In addition, the need for oil recovery can be satisfied with the recent rise in crude oil prices.

  The oil recovery device 10 should be portable by installing a vacuum evaporation tank 1, a condenser 2, a first separator 3 and a second separator 4, and, if necessary, a boiler on a base board and connecting pipes or the like. However, it is preferable in terms of easy access to the crude oil tank or the crude oil sludge storage tank. Further, the base board may be provided with wheels, or may be placed on the platform of an improved truck without attaching wheels. In the case where the vacuum distillation tank 1 is heated and steamed and is portable, the steam is received from the external boiler and the refrigerant is received from the external refrigerant supply source.

  EXAMPLES Next, although an Example is given and this invention is demonstrated more concretely, this is only an illustration and does not restrict | limit this invention.

  A vacuum evaporation tank with the following specifications was used as a test separator, a one-chamber gravity oil-water separator was used as the first separator, and a one-chamber gravity solid-liquid separator was used as the second separator. Except for the above, the oil content in the crude oil sludge A was recovered under the following operating conditions using the same device as the oil content recovery device in FIG. That is, the crude oil sludge A was introduced into the vacuum evaporation tank A and heated and stirred under vacuum to evaporate light oil and moisture in the crude oil sludge A. Next, the evaporated substance was cooled and separated into light oil and water, and the light oil was recovered. On the other hand, with the end of generation of the condensed liquid, the operation of the vacuum evaporation tank A was stopped, the vacuum state was returned to atmospheric pressure, and the residue was discharged from the lower part of the vacuum evaporation tank to the second separator. And the heavy oil isolate | separated with the 2nd separator was collect | recovered.

  As a result, 8.2% by weight of a light oil having a specific gravity of 0.770 was recovered from the first separator. No moisture was detected in this light oil. On the other hand, 20.6% by weight of heavy oil having a specific gravity of 0.950 to 0.990 was recovered from the second separator, and 48.1% by weight of the separation residue was recovered. The water content in this heavy oil was 0 (zero) wt%. The separation residue was mostly solid and contained a small amount of heavy oil. The amount of oil recovered from the crude oil sludge A was 98% (28.8% by weight / 29.3% by weight).

(Vacuum evaporation tank and operating conditions)
・ Vacuum evaporation tank A shown in FIG.
-Average rotation speed of stirring blades: 20 rotations / minute-Vacuum degree: -96 kPa, heating temperature (raw material temperature): 80-120 ° C
Evaporative material temperature (condenser inlet temperature); 50-85 ° C
・ Batch treatment: Raw material 47.8 kg, treatment for 2 hours ・ Crude oil sludge A: Moisture 22.9 wt%, oil content 29.3% wt, solid content 47.8 wt%
(Related equipment)
・ Heating means: Jacket system with steam heating from outside ・ Vacuum pump; Water seal type ・ Condenser: Cooling water used

  The same procedure as in Example 1 was performed except that the following vacuum evaporation tank and operating conditions were used. As a result, 5.1% by weight of a light oil having a specific gravity of 0.790 was recovered from the first separator. The water content in this light oil was 0.1% by weight or less. On the other hand, 13.1% by weight as a part of heavy oil was recovered from the second separator, and 60.1% by weight of the separation residue was recovered. The water content in the heavy oil was 1.0% by weight. The recovery rate as a liquid oil from crude oil sludge B was 58% by weight (18.2% by weight / 31.6% by weight). In addition, a part of heavy oil content is contained in the separation residue, and if the solid content or a mixture of the solid content and the heavy oil is used as the fuel, the recovery rate as an energy source is close to 100%.

(Vacuum evaporation tank and operating conditions)
・ Vacuum evaporation tank B shown in Fig.1
・ Average rotation speed of stirring blades: 20 rotations / minute ・ Vacuum degree: −100 kPa, heating temperature (raw material temperature): 75 to 97 ° C.
Evaporative material temperature (condenser inlet temperature): 45-50 ° C
・ Batch treatment: Raw material 41.2 kg, treatment for 5 hours ・ Crude oil sludge B: Moisture 20.4 wt%, oil content 31.6 wt%, solid content 48.0 wt%

  The same procedure as in Example 1 was performed except that the following vacuum evaporation tank and operating conditions were used. As a result, 9.2% by weight of light oil was recovered from the light oil separator. The water content in this light oil was 0.1% by weight or less. On the other hand, 13.4% by weight of heavy oil was recovered from the heavy oil separator, and 56.2% by weight of separation residue was recovered. The water content in the heavy oil was 1.0% by weight. The recovery rate as a liquid oil from crude oil sludge C was 64% by weight (22.6% by weight / 35.3% by weight). In addition, a part of heavy oil content is contained in the separation residue, and if the solid content or a mixture of the solid content and the heavy oil is used as the fuel, the recovery rate as an energy source is close to 100%.

(Vacuum evaporation tank and operating conditions)
・ Vacuum evaporation tank A shown in FIG.
-Average rotation speed of stirring blades: 20 rotations / minute-Vacuum degree: -94.3 kPa, heating temperature (temperature in the tank): 124.9 ° C
Evaporative material temperature (condenser inlet temperature): 58-80 ° C
・ Batch treatment: Raw material 44.7 kg, treatment for 2 hours ・ Crude oil sludge C: Moisture 21.0 wt%, oil content 35.3% wt, solid content 43.7 wt%

  If the oil content recovery apparatus of the present invention is used, since the recovered oil content hardly contains water, it can be recovered by blending it directly with crude oil or the like. The amount of crude oil sludge accumulated in a huge crude oil tank over a long period of time is large, and the oil recovered from it becomes a valuable resource under the recent rise in crude oil prices. In addition, since no chemical is used, secondary processing such as chemical processing becomes unnecessary, and the environmental load can be reduced.

  Crude oil and heavy oil spilled into the ocean, while drifting into the ocean, are affected by wind and waves, and heavy components such as asphaltene are mixed with seawater to form an emulsion. It causes great environmental pollution around the ocean and coast. In the past, oil pollutants that drifted or shored in the ocean were often treated as waste without collecting the oil, and in extreme cases, the drifting oil pollutants settled on the seabed with chemicals. For a long period of time, it caused enormous environmental pollution. On the other hand, the oil content recovery method of the present invention can treat such an oil pollutant as it is without using chemicals and can be separated into an oil content and a solid content, thereby reducing the waste treatment burden, Contributes greatly to global environmental conservation.

DESCRIPTION OF SYMBOLS 1 Vacuum evaporation tank 2 Condenser 3 1st separator 4 2nd separator 5 Vacuum pump 6 Crude oil tank or crude oil sludge storage tank 10 Oil content recovery apparatus in crude oil sludge

Claims (11)

A vacuum evaporation tank for subjecting crude oil sludge to vacuum evaporation;
A condenser for cooling the evaporated substance obtained in the vacuum evaporation tank;
A first separator for separating the condensate obtained from the condenser into light oil and water;
An oil content recovery device in crude oil sludge, comprising an evaporation residue take-off valve, and a pipe having one end connected to the vacuum evaporation tank.   And a second separator for separating the evaporation residue obtained in the vacuum evaporation tank into a heavy oil and a solid residue, and the pipe connects the vacuum evaporation tank and the second separator. The oil content recovery device in the crude oil sludge according to claim 1.   The oil content in the crude oil sludge according to claim 1, further comprising a recovery container for recovering the evaporation residue obtained in the vacuum evaporation tank, wherein the pipe connects the vacuum evaporation tank and the recovery container. Recovery device.   The oil content recovery device in crude oil sludge according to any one of claims 1 to 3, wherein the first separator is a gravity oil water separator.   The gravity type oil-water separator is divided into two chambers by a baffle plate having a predetermined height lower than the internal height. One of the chambers has a condensate inflow pipe and a water discharge pipe in the other chamber. The oil content recovery apparatus for crude oil sludge according to claim 4, wherein light oil content outflow pipes are connected to each other.   The oil content recovery apparatus for crude oil sludge according to claim 4 or 5, wherein the gravity oil / water separator is provided with a liquid level gauge for observing the interface level of the oil / water interface.   The oil content recovery apparatus for crude oil sludge according to claim 2, wherein the second separator is installed at a position below the vacuum evaporation tank.   The oil content recovery device in crude oil sludge according to claim 7, wherein the second separator is a gravity type solid-liquid separator.   The gravity type solid-liquid separator is divided into two chambers by a baffle plate having a predetermined height lower than the internal height, and one chamber has an evaporation residue inflow pipe and a solid content discharge pipe in the other. 9. The oil recovery apparatus for crude oil sludge according to claim 8, wherein a heavy oil discharge pipe is connected to each chamber. The gravity type solid-liquid separator is divided into three or more chambers whose height decreases from the upstream side to the downstream side by a plurality of baffle plates having different heights lower than the internal height. 9. The oil content in the crude oil sludge according to claim 8 , wherein an evaporation residue inflow pipe and a solid content discharge pipe are connected to the upstream chamber, and a heavy oil outflow pipe is connected to the most downstream chamber. Recovery device.   3. The oil content recovery device in crude oil sludge according to claim 2, wherein the vacuum evaporation tank, the condenser, the first separator, and the second separator are arranged on a base board to be portable. .

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