JP2018176059A - Method for treating water-containing oil waste and treatment equipment for water-containing oil waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treatment method of a water-containing oil waste liquid and a treatment apparatus of the water-containing oil waste liquid where an oil having a low water content can be efficiently recovered from the water-containing oil waste liquid, the amount of chemicals required for treatment is small and a COD load to an environment is low.SOLUTION: A treatment method of a water-containing oil waste liquid 1 includes: a first centrifugal separation step 12 separating the water-containing oil waste liquid 1 to three phases such as an oil phase 4, a water phase 6 and solid matter 8 by centrifugal separation without adding an emulsion breaker 3; an addition step adding the emulsion breaker 3 to the oil phase 4 separated by the first centrifugal separation step 12; and a second centrifugal separation step separating an oil phase added with the emulsion breaker 3 to three phases such as an oil phase 5, a water phase 7 and solid matter 9 by centrifugal separation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for treating a water-containing oil waste liquid for oil-water separation of water-containing oil waste liquid and recovering the oil, and a treatment equipment for water-containing oil waste liquid.

  Oil storage tanks (so-called oil tanks) are installed in the national oil stockpiling bases, the petroleum refining industry, the petrochemical industry, the coal chemical industry, and many other industries. These oil reservoirs need to be checked regularly, at which time all the stored oil is withdrawn and the tank is cleaned. The cleaning waste liquid is a mixed liquid of oil and water having various properties and forms depending on the properties of the stored oil.

  For example, if the storage oil is crude oil, “Crude Oil Washing” is performed to wash away the sludge accumulated in the tank with heated crude oil, and the sludge and water are converted to crude oil by finally performing warm water cleaning. Cleaning waste liquid called "warm water cleaning SLOP" mixed is discharged. Hot water cleaning SLOP contains sludge accumulated in a crude oil tank, high boiling point hydrocarbons such as wax and asphaltene contained in crude oil, components having a surface active action in crude oil, suspended substances, etc. Due to these inclusions, the oil and water contained in the warm water cleaning SLOP may be stably present as a W / O type or O / W type emulsion.

  From the viewpoint of effective utilization of resources, it is desirable to recover and refine the crude oil contained in the hot water cleaning SLOP. Also, the crude oil refining process is not originally supposed to process crude oil containing a large amount of water, and when processing a large amount of crude oil-containing waste liquid having a high water content such as hot water cleaning SLOP, warm water Due to the influence of water, salts and the like contained in the cleaning SLOP, problems such as corrosion of the purification equipment may occur. Therefore, the hot water cleaning SLOP is treated little by little, and there is a problem that the untreated hot water cleaning SLOP has to be stored in the storage tank for a long period of time. This problem is not limited to crude oil, but is a problem common to cleaning wastes of oil reservoirs other than crude oil.

For this reason, conventionally, various methods have been developed for separating and recovering oil from water-containing oil waste liquid which is washing waste liquid. For example, an oil-water separation device called API that raises oil by supplying oil-containing waste liquid to a water tank having a fixed residence time using the specific gravity difference between water and oil, and CPI using a slope plate has been put to practical use There is.
However, in the oil-water separator using such a difference in specific gravity, it is necessary to retain the waste liquid for a long time in the apparatus for separation, and there is a problem that the apparatus becomes large and the processing time is long. Moreover, in the separation method using a specific gravity difference, it has often been difficult to sufficiently separate water-containing oil waste liquid stabilized in the form of an emulsion into oil and water.

  In this respect, if a centrifuge is used, oil-water separation can be performed in a relatively short time (for example, Patent Documents 1 and 2). However, in the oil-water separation technology by centrifugation, it is pointed out that the problem is that the water content of the recovered oil is high (Patent Document 3).

  On the other hand, according to Patent Document 4, before supplying excess water (ammonia water) separated from the coal tar layer and the cocoon layer generated by the tarden tanker generated in the process of refining coke oven gas in a coke plant etc. In the above, there is disclosed a method and equipment for treating surplus low-cost water that is separated using a separation plate type centrifuge. Although this method uses two units, a centrifuge for centrifuging excess ammonium water separated by a tar decanter and a centrifuge for centrifuging coal tar, each centrifuge The targets to be treated are different, and it is not intended to improve the oil recovery efficiency by using two centrifuges installed in series for water-containing oil waste solution.

JP, 2006-104233, A JP, 2015-199848, A JP 2012-229403 A JP-A-59-112808

  The inventors of the present invention conducted intensive studies to solve the above-mentioned problems, and as a result, warm-water-washed SLOP was heated, and then a flocculant and an emulsion breaker were added, followed by oil-water separation by a centrifugal separator. It has been found that oil having a water content of about 1% can be recovered, and a patent application has already been filed (Japanese Patent Application No. 2016-43138).

  However, when an oil-soluble emulsion breaker is used in this method, the added emulsion breaker is selectively transferred to the recovered oil side, which may make purification difficult.

  On the other hand, even in the case of using a water-soluble emulsion breaker, there is a problem that the chemical oxygen demand (COD) of the aqueous phase becomes high because the emulsion breaker selectively shifts to the separated aqueous phase side. Moreover, the water-soluble emulsion breaker contained in the water phase in this way had the problem that removal with a coagulant | flocculant or activated carbon was difficult.

  The present invention has been made in view of the above-described conventional problems, and can efficiently recover an oil with low water content from water-containing oil waste liquid, reduce the amount of chemical required for treatment, and reduce the COD load on the environment. It is providing a disposal method of waste liquid and treatment equipment of water-containing oil waste liquid.

The method for treating water-containing oil waste liquid of the present invention is
A first centrifugation step in which the water-containing oil waste is separated into an oil phase, an aqueous phase and a solid by centrifuging without adding an emulsion breaker, and an oil phase separated in the first centrifugation step It is characterized by having an addition step of adding an emulsion breaker, and a second centrifugation step of three-phase separation of an oil phase, an aqueous phase and a solid by centrifuging the oil phase to which the emulsion breaker is added. I assume.

In the method for treating a water-containing oil waste liquid according to the present invention, first, as the first centrifugal separation step, the water-containing oil waste liquid is centrifuged without addition of the emulsion breaker, and the three phases of oil phase, water phase and solid matter It is separated. Therefore, the aqueous phase separated in the first centrifugation step does not contain the emulsion breaker, and even if it is discarded, the emulsion breaker does not increase the COD load on the environment. Then, as a second centrifugation step, an emulsion breaker is added to the oil phase separated from the water-containing oil waste liquid in the first centrifugation step (addition step), whereby the oil phase is emulsified and contained. The second centrifugation step is performed in a state in which the water is separated to form an aqueous phase. For this reason, the water content in the oil phase after the second centrifugation step is lower than the water content in the oil phase before the second centrifugation step. In addition, when the added emulsion breaker is water-soluble, it is selectively extracted in the aqueous phase obtained by the second centrifugation step, and when oil-soluble, it is in the oil phase obtained by the second centrifugation step Although selective extraction is performed, the addition of the emulsion breaker is only performed on the oil phase separated after the first centrifugation step, compared to the case where the emulsion breaker is added to the water-containing oil waste solution from the beginning and centrifuged Usage can be reduced. For this reason, the COD load by the emulsion breaker in each phase separated in the second centrifugation step is low.
Therefore, according to the method for treating water-containing oil waste liquid of the present invention, oil having a low water content can be efficiently recovered from water-containing oil waste liquid, the amount of chemical required for treatment can be small, and COD load on the environment can be reduced. .

  The emulsion breaker added in the second centrifugation step is not particularly limited as long as it breaks the emulsion in the water-containing oil waste solution, and a cationic emulsion breaker, an anionic emulsion breaker, a nonionic emulsion breaker, etc. Can be mentioned. Also, both water-soluble emulsion breakers and oil-soluble emulsion breakers can be used. Furthermore, multiple types of emulsion breakers may be added. Particularly preferred emulsion breakers include alkylphenol condensates.

  The equipment for treating water-containing oil waste liquid according to the first aspect of the present invention comprises a first centrifuge for separating water-containing oil waste liquid into an oil phase, an aqueous phase, and a solid, and the first centrifugal separation. Addition equipment for adding an emulsion breaker to an oil phase separated by a separator, and a second centrifugal separation in which the oil phase to which the emulsion breaker is added is further three-phase separated into an oil phase, an aqueous phase and a solid Characterized by having a machine

  In this water-containing oil waste disposal facility, the water-containing oil waste can be centrifuged by the first centrifuge without adding an emulsion breaker. Then, an emulsion breaker can be added to the oil phase obtained by three-phase separation by the first centrifuge using a drug addition facility. Furthermore, the oil phase to which the emulsion breaker has been added can be three-phase separated into an oil phase, an aqueous phase and a solid by a second centrifuge. That is, the method of treating water-containing oil waste liquid of the present invention can be carried out using the treatment apparatus of water-containing oil waste liquid of the present invention. Therefore, according to the equipment for treating water-containing oil waste liquid of the present invention, an oil having a low water content can be efficiently recovered from the water-containing oil waste liquid, the amount of chemical required for treatment can be small, and the COD load on the environment can be reduced. .

In the equipment for treating water-containing oil waste liquid according to the second aspect of the present invention, there is also provided a centrifuge for separating water-containing oil waste liquid into an oil phase, an aqueous phase and a solid, and oil separated by the centrifugal separator. A pharmaceutical addition facility for adding an emulsion breaker to the phase, and an oil storage facility for storing the oil phase to which the emulsion breaker is added;
The first flow path for supplying the water-containing oil waste to be treated to the centrifuge without adding the emulsion breaker, and the oil phase added with the emulsion breaker stored in the oil storage facility are centrifuged And a second flow path feeding the separator;
A flow path switching unit capable of switching between the first flow path and the second flow path is provided.

  In the equipment for treating water-containing oil waste liquid according to the second aspect of the present invention, first, the channel is switched to the first flow path by the flow path switching unit, and the water-containing oil waste liquid to be treated is supplied to the centrifuge. It can be centrifuged without adding an emulsion breaker to the water-containing oil waste solution. An emulsion breaker can be added to the oil phase separated in this way and to which the emulsion breaker has not been added, using a drug addition facility and stored in an oil storage facility. Furthermore, it is possible to switch to the second flow path by the flow path switching means, and to separate the oil phase to which the emulsion breaker is added into three phases of the oil phase, the water phase and the solid by the centrifuge. That is, by switching the flow path by the flow path switching means, the method for treating water-containing oil waste liquid of the present invention can be carried out using only one centrifugal separator. For this reason, the equipment can be miniaturized as compared with the case where two centrifuges are used, and the equipment cost can also be reduced.

In the treatment equipment for water-containing oil waste liquid of the present invention, it is preferable that a heating equipment for heating the water-containing oil waste liquid to be treated is provided.
By heating the water-containing oil waste liquid, the waxes contained in the water-containing oil waste liquid are melted and dissolved in the oil phase side, so the oil droplets come into direct contact with the surrounding water to destabilize the interface and the oil droplets Three-phase separation is promoted by association and coarsening. In addition, the suspended solids contained in the waste water containing oil have the role of stabilizing the emulsion by covering the oil droplets (or water droplets) together with the waxes, but the waxes deposited on the suspended solids by heating Dissolution and removal in oil also destabilizes the emulsion. Furthermore, heating the water-containing oil waste solution removes waxes from the suspended solids, so that the oil content in the separated solid is reduced. Further, by heating the water-containing oil waste liquid, the viscosity of the water-containing oil waste liquid is reduced, the emulsion breaker is easily mixed, and the emulsion breaking effect is easily exhibited.

  According to the present invention, it is possible to quickly recover an oil having a low water content, with little influence of a drug added for oil-water separation from the water-containing oil waste, so the water-containing oil waste that has not been used conventionally. The oil contained therein can be recovered, purified and effectively used. In addition, since the amount of use of the emulsion breaker is reduced, not only the processing cost is reduced, but also the COD load on the environment can be reduced.

FIG. 2 is a schematic view of a crude oil-containing waste liquid treatment apparatus of Example 1; FIG. 6 is a schematic view of a crude oil-containing waste liquid treatment facility of Example 2. FIG. 7 is a schematic view of a crude oil-containing waste liquid treatment system of Example 3. FIG. 16 is a schematic view showing a first path and a second path in the crude oil-containing waste liquid treatment facility of Example 3. It is a schematic diagram of the processing installation of the crude oil containing waste liquid of comparative example 1.

  The emulsion breaker used in the present invention is not particularly limited as long as it breaks the emulsion in the water-containing oil waste solution, and a cationic emulsion breaker, an anionic emulsion breaker, a nonionic emulsion breaker, etc. may be mentioned. . Also, both water-soluble emulsion breakers and oil-soluble emulsion breakers can be used. Furthermore, multiple types of emulsion breakers may be added.

Examples of the anionic emulsion breaker include a sulfuric acid ester type and a sulfonic acid type emulsion breaker. As a sulfate ester type emulsion breaker, for example, polyoxyalkylene alkyl ether sulfate (more preferably polyoxyalkylene alkyl ether sulfate having an average addition mole number of 1 to 5 of polyoxyalkylene chain), alkyl ether sulfate ester salt (The alkyl ether sulfate ester salt having 8 to 22 carbon atoms of the alkyl group is more preferable) and the like. Moreover, as an emulsion breaker of a sulfonic acid type, for example, dialkyl sulfosuccinate salts, petroleum sulfonates, naphthalene sulfonates, alkyl naphthalene sulfonates (more preferably, alkyl naphthalene sulfone having an alkyl group of 1 to 5 carbon atoms) Acid salts and the like.
When these emulsion breakers are salts, the type of salt includes ammonium salt, alkali metal (potassium, sodium etc.) salt, alkaline earth metal (calcium, barium etc) salt, tertiary amine (eg monoethanol) Amine, diethanolamine, triethanolamine etc. etc. are mentioned. Examples of the polyoxyethylene alkyl ether sulfate ester salt include polyoxyethylene lauryl ether triethanolamine tribasic and polyoxyethylene lauryl sodium sulfate.

  Moreover, as a nonionic emulsion breaker, for example, polyoxyalkylene alkyl ether, alkylphenol alkylene oxide adduct / formalin condensate, polyalkylene glycol copolymer, alkylene oxide adduct of alkylamine, polyether polyol urethane resin, etc. Can be mentioned.

  Furthermore, as a cationic emulsion breaker, a polyamine compound (for example, N-polyoxyethylene polyalkylene polyamine etc.) is mentioned.

  Particularly preferred emulsion breakers are alkylphenol condensates. The present inventors confirmed that oil-water separation by centrifugation is more effectively performed by using an alkylphenol condensate as an emulsion breaker. As an alkyl phenol condensate, the alkylene oxide adduct of an alkyl phenol condensate etc. are mentioned, for example. Hakutoru E-523 (trade name) manufactured by Shoto Co., Ltd. contains a nonionic alkylphenol condensate. In addition, the present inventors have also used a cationic polymer such as EW-01 (trade name) manufactured by Shoto Co., Ltd. or an anionic surfactant such as EW-02 (trade name) by centrifugation. It was confirmed that it was suitable for effective oil-water separation.

  Hachtole E-523, which is oil soluble, acts on the emulsion and then moves mainly to the separated oil side, and there is little remaining on the water (heavy liquid) side, so the advantage is that processing of the heavy liquid becomes easy. is there. On the other hand, since EW-01 and EW-02 are water soluble, they act on the emulsion and then move mainly to the separated heavy liquid side, and there is little residue on the oil side, and the quality of recovered oil and the purification process It has the advantage that the impact is small. An appropriate type of emulsion breaker may be appropriately determined in consideration of the required quality of the recovered oil and the processing equipment for heavy liquid. With regard to the addition amount of the emulsion breaker, it is preferable to conduct an oil-water separation test in advance on a small scale to determine the optimum addition amount.

  Heating is also effective for oil-water separation of the emulsified hydrous oil waste solution. In a crude oil-containing waste liquid such as warm water-washed SLOP, the waxes cover the oil droplets (or water droplets) as described above to prevent the oil droplets from coming into direct contact with the surrounding water, thereby stabilizing the emulsion. By the way, since waxes melt on the oil side when heated, they will dissolve when the water-containing oil waste liquid is heated, and the oil droplets will be in direct contact with the surrounding water to destabilize the interface, so the oil droplets are associated Oil and water separation is promoted by coarsening.

  In addition, the suspended solids contained in the emulsified hydrous waste oil have the role of stabilizing the emulsion by covering the oil droplets (or water droplets) with the waxes, but floating by floating The wax adhering to the substance is also dissolved and removed in the oil to destabilize the emulsion and facilitate oil-water separation. In addition, suspended matter is recovered as sludge in a centrifugal separation step, but the effect of reducing the oil content in the sludge can also be expected by removing waxes from the suspended matter by heating.

  Furthermore, heating the emulsified hydrous oil waste liquid has the effect of reducing the viscosity of the hydrous oil waste liquid, so that the added drug can be easily mixed with the waste liquid, and as a result, emulsion destruction and oil / water separation due to drug addition The effect to promote can be expected.

  From the above reasons, it is preferable to heat the water-containing oil waste solution to a temperature of 45 ° C. or higher. If the temperature of the waste solution is less than 45 ° C., there is a possibility that the wax stabilizing the emulsion of the waste solution may not be dissolved, so that it is difficult to break the emulsion due to the dissolution of the waxes and the oil / water separation may be difficult . In addition, when the temperature of the waste solution is less than 45 ° C., the viscosity of the waste solution does not decrease so much that the effect of facilitating the mixing of the added drug is difficult to be exhibited, and also the oil / water separation may be difficult.

  On the other hand, when the temperature of the water-containing oil waste liquid rises, the volatilization of the oil component in the water-containing oil waste liquid is promoted. Therefore, the temperature of the waste liquid is preferably 65 ° C. or less. In particular, since it exceeds the flash point of heavy oil which is generally considered to be difficult to ignite if the temperature of the waste liquid exceeds 60 ° C., it is more preferable to heat the water-containing oil waste liquid to 55 ° C. or less. In addition, it is desirable that each facility be sealed so that combustible gas does not leak easily so that the volatilized oil component does not stay around the facility. In addition, it is desirable to have a structure in which the gas volatilized from each facility is sucked and volatilized in a safe place.

  From the above reasons, heating of the waste liquid is preferably in the range of 45 ° C. to 65 ° C., and more preferably in the range of 45 ° C. to 55 ° C.

  In the treatment of the aqueous phase (heavy liquid) obtained from the centrifugation step of the present invention, a flocculant can also be used to coagulate particles and oil droplets in water. As a coagulant | flocculant, the coagulant | flocculant which consists of a polymeric coagulant | flocculant and inorganic salt is mentioned, for example. As the polymer coagulant, any or a plurality of cationic polymer coagulants, anionic polymer coagulants, and nonionic polymer coagulants may be appropriately selected in consideration of the surface charge and the like of the particles in the heavy liquid. Just do it. Moreover, as a coagulant | flocculant which consists of mineral salts, aluminum sulfate (sulfated earth), poly aluminum chloride, iron chloride, poly iron sulfate, etc. are applicable.

Examples of cationic polymer flocculants include polyamines, polyimines, polydiallyldialkyl ammonium chlorides, Mannich modified products of polyacrylamide and the like. Particularly preferred are polyamine flocculants. Examples of polyamine flocculants include polyamine condensates.
In addition, examples of the anionic polymer flocculant include poly (meth) acrylic acid and salts thereof.
Moreover, as a nonionic high molecular coagulant | flocculant, a poly (meth) acrylamide etc. are mentioned, for example.

<Water-containing oil waste treatment facility>
Example 1
The treatment facility of Example 1 is a facility for treating a crude oil-containing waste liquid, and as shown in FIG. 1, has a heating facility 11 for heating the crude oil-containing waste fluid 1 by heating steam 2 The crude oil-containing waste liquid 1 warmed by the heating facility 11 is fed to the first centrifuge 12. The first centrifuge 12 is a three-phase separation type centrifugal separator capable of separating the crude oil-containing waste liquid 1 into three components of a light liquid 4 consisting of an oil phase, a heavy liquid 6 consisting of an aqueous phase, and a sludge 8 consisting of solid matter. It is a separator. The first centrifuge 12 is connected to a mixing tank 13 with a stirrer that stores the separated light liquid 4. The mixing tank 13 is provided with a medicine addition facility 13 a for supplying the emulsion breaker 3, and the mixing tank 13 is connected to the second centrifuge 14. Similar to the first centrifuge 12, the second centrifuge 14 is also a three-phase separation type centrifuge that can be separated into three components.

  In the crude oil-containing waste liquid treatment facility of Example 1 configured as described above, the crude oil-containing wastewater 1 is first sent to the heating facility 11 and heated by the heating steam 2. The heated crude oil-containing waste liquid 1 is supplied to the first centrifuge 12, and the light liquid 4 containing oil as a main component and the heavy liquid 6 containing water as a main component are separated, and further sand, iron, etc. The sludge 8 whose main component is inorganic matter is discharged by a screw (not shown) in the first centrifuge 12. In addition, in the centrifugation process by the 1st centrifuge 12, since an emulsion breaker is not added, an emulsion breaker is not contained in the light liquid 4, the heavy liquid 6, and the sludge 8. FIG. The feed rate of the crude oil-containing waste liquid 1 to the first centrifuge 12 is appropriately determined so that sufficient oil-water separation is performed in consideration of the water content in the discharged light liquid 4 and the oil content of the heavy liquid 6 decide. Usually, the feed amount of the crude oil-containing waste liquid 1 is determined so that the water content in the light liquid 4 is 10% by weight or less, more preferably 5% by weight or less. By performing such management, most of the water contained in the crude oil-containing waste liquid 1 is discharged as the heavy liquid 6.

  Thus, the light liquid 4 separated by the first centrifuge 12 is mixed with the emulsion breaker 3 in the mixing tank 13 and then supplied to the second centrifuge 14 and mainly contains the recovered oil 5 and water. It is separated into heavy liquid 7 and sludge 9.

  As described above, according to the treatment facility of Example 1, the three-phase separation is performed by the first centrifuge 12 without adding the emulsion breaker to the crude oil-containing waste fluid 1 to be treated, and the sludge 8 and the heavy liquid 6 are separated. And are excluded. Then, the emulsion breaker 3 is added only to the light liquid 4 discharged from the first centrifuge 12, and the three phases are separated into the sludge 9, the heavy liquid 7 and the recovered oil 5. For this reason, compared with the case where three phases of crude oil-containing waste liquid to which the emulsion breaker 3 is added is separated in a single centrifuge, the amount of use of the emulsion breaker 3 can be reduced, and the COD load on the environment is reduced. . Further, since the light liquid 4 separated by the first centrifuge 12 is further subjected to three-phase separation using the second centrifuge 14 to obtain the recovered oil 5, the recovered oil having a low water content from the crude oil-containing waste liquid 1 5 can be recovered efficiently.

  In this crude oil-containing waste liquid treatment facility, some of the oil and sludge contained in the crude oil-containing waste liquid 1 may remain in the heavy liquid 6 separated from the first centrifuge 12. Since the emulsion breaker is not included and the COD load is small, it can be discarded only by performing a relatively simple treatment method. For example, a separation method utilizing the difference in specific gravity between oil and water, such as an API oil separator or a CPI oil separator, or the like, application of pressure flotation, coagulation sedimentation, etc. can be considered.

On the other hand, the heavy liquid 7 separated by the second centrifuge 14 contains the emulsion breaker 3, so the COD value is higher than that of the heavy liquid 6. In particular, in the case where a water-soluble emulsion breaker 3 is used, the rate at which the emulsion breaker is transferred to the heavy liquid 7 is high, so the COD value in particular is high.
However, most of the water contained in the crude oil-containing waste water 1 is transferred into the heavy liquid 6 by separation by the first centrifuge 12, so the water content in the light liquid 4 is small, and the second centrifugal separation The amount of heavy liquid 7 separated by the machine is extremely small. Therefore, by mixing heavy liquid 7 with a large COD value into a large amount of heavy liquid 6 that has a small COD value and is easy to process, the overall COD load can be reduced, and the processing method for disposal is also easy. It becomes. In addition, since the heavy liquid 7 is generated in a small amount, the entire amount can be disposed of as industrial waste.

  Although the crude oil-containing waste liquid 1 has been described as the crude oil-containing waste liquid treatment facility of Example 1, the same treatment is possible if it is a water-containing oil waste liquid in which oil and water are mixed. For example, SLOP in which various waste oils and various cleaning wastewaters and sludges are mixed can be treated. Since SLOP contains a wax component derived from waste oil and a component having surface activity, the wax component and the component having surface activity gather at the interface between water and oil contained in SLOP, making it difficult for water and oil to directly contact with each other. Form In this state, it is in the form of an O / W type emulsion in which minute oil droplets are stably present in water or a W / O type emulsion in which minute water droplets are stably present in oil.

(Modification of Embodiment 1)
-About the mixing tank 13 It replaces with the mixing tank 13 which provided the stirring apparatus, and the method of installing and mixing a line mixer in piping middle is also applicable. In addition, it is not essential to provide a stirring device in the mixing tank 13, and it may be appropriately determined whether to install according to the mixing state of the emulsion breaker 3 and the light liquid 4.
The facility for heating the light liquid 4 The higher the temperature of the light liquid 4, the lower the viscosity, the easier the mixing with the emulsion breaker 3 becomes, and the higher the liquid temperature, the more unstable the emulsion becomes. It is preferable to provide equipment for heating the light liquid 4. Moreover, when the temperature of the light liquid 4 falls in the isolation | separation process by the 1st centrifuge 12, it is desirable to install the installation which can heat the light liquid 4 again with a heat exchanger etc. as needed. Furthermore, it is desirable that each facility and piping have a heat insulating structure using a heat insulating material or the like.

(Example 2)
The processing facility of the second embodiment is a facility for treating a crude oil-containing waste liquid such as a hot water washing SLOP as in the first embodiment, and the heating facility 11 of the system of blowing the steam directly in the first embodiment (see FIG. 1). Instead of the above, as shown in FIG. 2, a crude oil-containing waste storage tank 15 and a heat exchanger 16 are provided, and the crude oil-containing waste liquid 1 is circulated between the crude oil-containing waste storage tank 15 and the heat exchanger 16 The waste liquid 1 is heated.
Moreover, the mixing tank 13 (refer FIG. 1) in Example 1 is not provided, but instead, as shown in FIG. 2, the light fluid 4 discharged | emitted from the 1st centrifuge 12 is 2nd centrifuge A medicine addition facility 23 for supplying the emulsion breaker 3 directly to the piping 22 for feeding the solution 14 is provided, and is mixed by a line mixer (not shown). The other parts are the same as those of the first embodiment, and the same reference numerals are given to the same components and the detailed description will be omitted.

  In the processing facility of Example 2 configured as described above, the crude oil-containing waste fluid 1 heated by the heat exchanger 16 is sent to the first centrifuge 12 without the addition of the emulsion breaker, and And the heavy liquid 6 and the sludge 8 are separated into three phases. Then, the emulsion breaker 3 is added to the light liquid 4 from the medicine addition equipment 23 and is sent to the second centrifuge 14, and the three phases are separated into the recovered oil 5, the heavy liquid 7 and the sludge 9. For this reason, the amount of use of the emulsion breaker 3 can be reduced, and the COD load on the environment is reduced, as in the processing equipment of the first embodiment. In addition, since the two-step centrifugal separation process is performed, an oil with a low water content can be efficiently recovered from the crude oil-containing waste liquid.

(Example 3)
The processing facility of Example 3 is also a facility for treating a crude oil-containing waste liquid such as warm water washing SLOP, and as shown in FIG. 3, a crude oil-containing waste liquid storage tank 32 for storing crude oil-containing waste liquid 31 and a heat exchanger 33 The crude oil containing waste liquid 31 stored in the crude oil containing waste liquid storage tank 32 is heated by circulating between the crude oil containing waste liquid storage tank 32 and the heat exchanger 33. Further, the crude oil-containing waste liquid 31 in the crude oil-containing waste liquid storage tank 32 can be sent to the centrifuge 36 through the three-way solenoid valve 35. The centrifugal separator 36 is a three-phase separation type centrifugal separator capable of separating the crude oil-containing waste liquid 31 into three components of a light liquid 37 consisting of an oil phase, a heavy liquid 38 consisting of an aqueous phase, and a sludge 39 consisting of solids. It is. The light liquid 37 separated by the centrifugal separator 36 is connected to a light liquid storage tank 42, which is an oil storage facility, via a three-way electromagnetic valve 41, and the light liquid storage tank 42 is further connected to the three-way electromagnetic valve 35. . In addition, the light liquid storage tank 42 is provided with a medicine addition facility 42 a for supplying the emulsion breaker 43. The heavy liquid 38 separated by the centrifugal separator 36 is drained from one of the two drainage pipes 40 a and 40 b through the three-way solenoid valve 40.

In the processing equipment of the third embodiment configured as described above, first, the three-way solenoid valves 35, 40, 41 are driven to be set in the first flow path shown in FIG. 4A.
That is, the crude oil containing waste liquid 31 stored in the crude oil containing waste liquid storage tank 32 is heated by circulating between the crude oil containing waste liquid storage tank 32 and the heat exchanger 33, and the three-way solenoid valve 35 is driven to drive the crude oil containing waste liquid 31. The flow path can be sent to the centrifuge 36. As a result, the heated crude oil-containing waste liquid 31 is supplied to the centrifugal separator 36 via the three-way solenoid valve 35, and consists of the light liquid 37 consisting of the oil phase, the heavy liquid 38 consisting of the water phase, and solids. It is separated into three components with the sludge 39. Thus, the light liquid 37 separated by the centrifugal separator 36 is sent to the light liquid storage tank 42 by the flow path setting by the three-way solenoid valve 41, and the emulsion breaker 43 is added by the medicine addition facility 42a. In addition, since the flow path from the light liquid storage tank 42 to the three-way solenoid valve 35 is in a closed state, the light liquid 37 is continuously stored in the light liquid storage tank 42. On the other hand, the heavy liquid 38 separated by the centrifuge 36 is sent to the drainage pipe 40 a by the flow path setting by the three-way solenoid valve 40.

As described above, after the light liquid 37 to which the emulsion breaker 43 is added is sufficiently stored in the light liquid storage tank 42 in the state of the first flow path shown in FIG. 4A, the three-way solenoid valves 35, 40 41 are driven to set the second flow path shown in FIG. 4 (b).
That is, the three-way solenoid valve 35 is driven to close the flow path from the crude oil-containing waste liquid storage tank 32 to the centrifuge 36 and to open the flow path from the light liquid storage tank 42 to the centrifuge 36. Thereby, the light liquid 37 stored in the light liquid storage tank 42 and to which the emulsion breaker 43 is added is supplied to the centrifuge 36, and the recovered oil 44, the heavy liquid 38 consisting of the water phase, and the sludge consisting of solids 39 are separated into three components. Thus, the light liquid 37 separated by the centrifuge 36 is recovered as the recovered oil 44 without being sent to the light liquid storage tank 42 by the flow path setting by the three-way solenoid valve 41. On the other hand, the heavy liquid 38 separated by the centrifuge 36 is sent to the drainage pipe 40 b by the flow path setting by the three-way solenoid valve 40.

  According to the processing equipment of the third embodiment, the light liquid 37 which is three-phase separated without the addition of the emulsion breaker by the centrifugal separator 36 by the operation of the flow path by switching the three-way solenoid valve 35, 40, 41 With the breaker 43 added, the sludge 39, the heavy liquid 38 and the recovered oil 44 can be obtained again. For this reason, compared with the case where oil breaker is directly recovered by adding the emulsion breaker to the crude oil-containing waste liquid supplied to the centrifugal separator, the amount of use of the emulsion breaker can be reduced, and the COD load to the environment is low. Become. In addition, since the two-step centrifugal separation process is performed, an oil with a low water content can be efficiently recovered from the crude oil-containing waste liquid. Moreover, since only one centrifugal separator 36 is used in the processing equipment of Example 3, as compared with the case where two centrifugal separators are used as in the processing equipment of Example 1 and Example 2. Thus, the equipment can be miniaturized, and the equipment cost can also be reduced.

  In addition, in the processing equipment of the third embodiment, in order to switch between the first flow path and the second flow path, the processing is not continuous processing but batch processing, and it is necessary to temporarily interrupt the processing. In addition, when the light liquid 37 is supplied to the centrifuge 36, sludge and the like when the crude oil-containing waste liquid 31 is centrifuged remains in the centrifuge 36, and these are mixed in the recovered oil 44. There is a fear. For this reason, when switching from the first flow path to the second flow path, it is preferable to clean the inside of the centrifuge 36 and the piping connected to this as needed.

(Modification of Embodiment 3)
Flow Channel Switching Means In the processing equipment of the third embodiment, switching of the first flow channel and the second flow channel is performed using three three-way solenoid valves. However, the first flow channel and the second flow channel are switched. Other channel switching means may be used if it is possible to switch between the channels. For example, a method of combining two two-way valves instead of the three-way solenoid valve may be mentioned.
The facility for heating the light liquid 37 The higher the temperature of the light liquid 37, the lower the viscosity, the easier mixing with the emulsion breaker 43, and the higher the liquid temperature, the more unstable the emulsion, It is preferable to provide equipment for heating the light liquid 37. When the temperature of the light liquid 37 is lowered in the light liquid storage tank 42, it is desirable to install equipment capable of reheating the light liquid 37 with a heat exchanger or the like as necessary. Furthermore, it is desirable that each facility and piping have a heat insulating structure using a heat insulating material or the like.

(Comparative example 1)
The treatment facility of Comparative Example 1 is also a facility for treating a crude oil-containing waste liquid such as warm water washing SLOP, and as shown in FIG. 5, a crude oil-containing waste liquid storage tank 101 and a heat exchanger 102 for storing the crude oil-containing waste liquid 100. The crude oil-containing waste liquid 100 is heated while being circulated between the crude oil-containing waste liquid storage tank 101 and the heat exchanger 102. The crude oil-containing waste liquid storage tank 101 is connected to a centrifuge 107 via a pipe 104. In the middle of the pipe 104 is connected a medicine addition facility 105 for feeding the emulsion breaker 106 into the pipe 104. The centrifuge 107 is capable of separating the crude oil-containing waste fluid 100 to which the emulsion breaker 106 is added into three components of a recovered oil 108 consisting of an oil phase, a heavy liquid 109 consisting of an aqueous phase, and a sludge 110 consisting of solids. It is a phase separation type centrifuge.

  In the crude oil-containing waste liquid treatment facility of Comparative Example 1 configured as described above, the emulsion breaker 106 is added to the entire amount of the crude oil-containing waste liquid 100 to be treated, and then the three phases are separated by the centrifuge 107, The recovered oil 108 is obtained, and the sludge 110 and the heavy liquid 109 are removed. That is, in order to obtain the recovered oil 108 in only one process by the centrifuge 107, the water content contained in the recovered oil 108 as compared with the processing equipment of Examples 1 to 3 in which the centrifugal separation process is performed in two steps. Will increase. In addition, since the emulsion breaker 106 is added to the entire amount of the crude oil-containing waste liquid 100 and then centrifugal separation is performed, the content of the emulsion breaker 106 contained in the recovered oil 108, the sludge 110, and the heavy liquid 109 increases. This increases the COD load on the environment.

<Treatment test of hydrous oil waste liquid>
(Example 4)
In Example 4, the treatment test of the hot water washing SLOP of the crude oil storage tank was performed using the crude oil-containing waste liquid treatment apparatus of Example 2 described above.

・ First centrifugation step S1
The water content of the hot-water-washed SLOP used in the test was 18.6%. The hot water cleaning SLOP was supplied to the crude oil-containing waste liquid storage tank 15 of Example 2 shown in FIG. 2, and the warm water cleaning SLOP was first heated to about 55 ° C. using a circulation line including the heat exchanger 16. The heated warm water cleaning SLOP was then supplied to the first centrifuge 12. The amount of undiluted solution supplied to the centrifuge 12 at this time was 500 L per hour, and the centrifugal force was set to 2500 G. Also, the throughput was about 150 kg. The moisture content of the light liquid 4 discharged from the first centrifuge 12 was about 2.6%, and the amount of generation was 121 kg. On the other hand, 22 kg of heavy liquid 6 was generated and contained black suspended solids. The amount of sludge 8 generated was 6 kg.

・ Addition process S2
To light liquid 4 recovered in the first centrifugal separation step S1, Haktole E-523 (manufactured by Shoto Co., Ltd.) containing an alkylphenol condensation product as emulsion breaker 3 was added at a ratio of 10 mg per liter of light liquid.

· Second centrifugation step S3
Thus, the light liquid 4 to which E-523 was added was supplied to the second centrifuge 14. The amount of light liquid 4 supplied to the second centrifuge 14 was set to 500 L / hr, as in the first centrifugation step S1. Thus, recovered oil 5 and heavy liquid 7 were obtained by the second centrifuge 14. Heavy liquid 7 had a slightly brownish clear aspect. While the moisture content of the light liquid 4 was about 2.6%, the moisture content of the recovered oil 5 was reduced to 1.4%.
On the other hand, the heavy liquid 6 discharged had a COD concentration of 672 mg / L and an amount of generation of about 147 L per 1000 kg of warm water-washed SLOP. The heavy liquid 7 had a COD concentration of 151 mg / L, and the amount of generation was about 10 L per 1000 kg of warm water-washed SLOP.

  Add 200 mg / L of Haktron B-733 (manufactured by Shoto Co., Ltd.) as a coagulant to the heavy liquid 6 obtained in Example 4 at a ratio of 200 mg / L and 6 mg / L of A-151 (manufactured by Watering Co., Ltd.) As a result, the obtained supernatant COD was 153 mg / L, and it was found that the flocculation treatment was effective for the heavy liquid treatment after the first centrifugation. On the other hand, although heavy liquid 7 hardly reduced COD in the same treatment, it was considered that treatment such as combustion as an industrial waste was appropriate because the amount of generation is small.

(Example 5)
In the same manner as in Example 4, Example 5 used the crude oil-containing waste liquid treatment apparatus of Example 2 to conduct a treatment test of the hot water washing SLOP of the crude oil storage tank.

・ First centrifugation step S1
The water content of the hot-water-washed SLOP used in the test was 18.6%.
The hot water cleaning SLOP was supplied to the crude oil-containing waste liquid storage tank 15, and first, the hot water cleaning SLOP was heated to about 55 ° C. using a circulation line including the heat exchanger 16. The heated warm water cleaning SLOP was then supplied to the first centrifuge 12. The amount of undiluted solution supplied to the first centrifuge 12 at this time was set to 500 L per hour, and the centrifugal force was set to 2500 G. Also, the throughput was about 150 kg. The moisture content of the light liquid 4 discharged from the first centrifuge 12 was about 2.6%, and the amount of generation was 121 kg. On the other hand, 22 kg of heavy liquid 6 was generated and contained black suspended solids. The amount of sludge 8 generated was 6 kg.

・ Addition process S2
The emulsion breaker 3 was added to the recovered light liquor 4 and mixed well. In Example 5, as an emulsion breaker different from Example 4, both of cationic polymer EW-01 (manufactured by Shoto Co., Ltd.) and anionic surfactant EW-02 (manufactured by Shoto Co., Ltd.) were added. The amount of addition was 300 mg of EW-01 and 30 mg of EW-02 per liter of light liquid.

· Second centrifugation step S3
After the addition of the emulsion breaker 3, the light liquid 4 was supplied to the second centrifuge 14. The amount of light liquid 4 supplied to the second centrifuge 14 was set to 500 L / hr, as was the amount supplied to the first centrifuge 12. Recovered oil 5 and heavy liquid 7 were obtained by the second centrifuge 14. Heavy liquid 7 had a slightly brownish clear aspect. The moisture content of the recovered oil 5 is 0.8%, which is reduced to 1/3 or less compared to the moisture content of the light liquid 4 before centrifugation and reduced to 1/3 or less, and the emulsion breaker is mixed and then centrifuged. It was found that the separated oil can provide a recovered oil with low water content. The COD concentration of the discharged heavy liquid 6 was 670 mg / L, and the amount generated was about 147 L per 1000 kg of warm water-washed SLOP. The heavy liquid 7 had a COD concentration of 12400 mg / L, and the amount of generation was about 15 L per 1000 kg of warm water-washed SLOP.

Comparison of Example 4 and Example 5
The COD of the heavy liquid 7 of Example 4 discharged from the second centrifuge 14 is compared with that of Example 5, although Example 4 and Example 5 were tested using exactly the same warm water-washed SLOP. It was extremely low. The cause of this is that the emulsion breaker used in Example 5 is water-soluble while the emulsion breaker used in Example 5 is water-soluble, while the emulsion breaker used in Example 5 is mainly separated. It was considered that the extract was selectively extracted to the heavy liquid 7 side.
The COD concentration of heavy liquid 7 in Example 5 was increased, but the amount generated is about 15 L per 1000 kg of warm water-washed SLOP, and generation of heavy liquid 6 with low COD obtained by centrifugation with the first centrifuge 12 It was found that the amount was small compared to about 147 L of the volume, and high concentration COD waste solution could be reduced.

(Example 6)
In Example 6, using the crude oil-containing waste liquid treatment apparatus of Example 2, a treatment test of oil-impregnated sludge at the bottom of the SLOP tank of a petroleum refining plant was conducted. In oil refineries, oily waste water generated in the plant and oily waste liquid such as process oil at the time of equipment shutdown are collected in a storage tank called SLOP tank, and water separated from the lower layer is drained. A SLOP consisting of oil and sludge and oil-containing sludge mixed with water is generated. This SLOP was subjected to the test. The water content of SLOP was 63.3%.

・ First centrifugation step S1
The SLOP was supplied to the crude oil-containing waste storage tank 15, and was first heated to about 55 ° C. using a circulation line including the heat exchanger 16. The warmed SLOP was then fed to the first centrifuge 12. The amount of SLOP supplied to the centrifuge 12 at this time was set to 500 L per hour, and the centrifugal force was set to 2500 G. Also, the throughput was about 250 kg. The moisture content of the light liquid 4 discharged from the first centrifuge 12 was about 8%, and the amount of generation was 77 kg. On the other hand, 152 kg of heavy liquid 6 was generated and contained black suspended solids. The amount of sludge 8 generated was 21 kg.

・ Addition process S2
The emulsion breaker 3 was added to the recovered light liquor 4 and mixed well. As in Example 5, EW-01 as a cationic polymer and EW-02 as an anionic surfactant were added as an emulsion breaker. The addition rate was 300 mg EW-01 and 30 mg EW-02 per liter of light liquor.

· Second centrifugation step S3
After addition of the emulsion breaker, light liquid 4 was supplied to the second centrifuge 14. The amount of light liquid 4 supplied to the second centrifuge 14 was set to 500 L / hr, similarly to the amount of SLOP supplied to the first centrifuge. The recovered oil 5 and the heavy liquid 7 were obtained by the three-phase separation with the second centrifuge 14. Heavy liquid 7 had a slightly brownish clear aspect. The moisture content of the recovered oil 5 is 1.4%, which is lower than the moisture content of 8% of the light liquid 4 before three-phase separation, and by mixing the emulsion breaker and centrifuging, the moisture content is low. It turned out that the recovered oil could be obtained.

(Comparative example 2)
In Comparative Example 2, the crude oil-containing waste liquid treatment facility of Comparative Example 1 shown in FIG. 5 was used to conduct a treatment test of the hot water washing SLOP of the crude oil storage tank.

・ Addition process S4
The water content of the hot-water-washed SLOP used in the test was 18.6%.
The hot water cleaning SLOP was supplied to the crude oil-containing waste liquid storage tank 101, and the hot water cleaning SLOP was first heated to 55 ° C. using a circulation line including the heat exchanger 102. Next, the emulsion breakers EW-01 and EW-02 were added to the heated warm water washing SLOP. The addition rate of EW-01 was set to 300 mg per 1 L of warm water cleaning SLOP, and the addition rate of EW-02 was set to 30 mg.

· Centrifugation step S5
After the emulsion breaker was added, the hot water washed SLOP was supplied to the centrifuge 107. The raw water supply amount to the centrifuge 107 at this time was set to 500 L per hour. Thus, about 118 kg of recovered oil 108, about 26 kg of heavy liquid 109 and about 6 kg of sludge 110 were recovered.

The COD of the heavy liquid 109 was 2000 mg / L, and the amount of generation was about 175 L per 1000 kg of warm water-washed SLOP, and the amount of generation of a high COD waste solution was increased as compared with Example 4 and Example 5. The heavy liquid 109 obtained in Comparative Example 2 had 200 mg / L of Haktron B-733 (manufactured by Shoto Co., Ltd.) and 6 mg / L of A-151 (manufactured by Watering Co., Ltd.) as a coagulant as in Example 4. The addition of 20000 mg / L of powdered activated carbon was also carried out, but the COD of the obtained supernatant was 185 mg / L, as compared with Example 4. The drug injection rate has increased significantly. From this result, it was found that in the one-step centrifugation shown in Comparative Example 2, the generation amount of the heavy liquid including the emulsion breaker which is difficult to process is increased. On the other hand, in Examples 4 and 5, since the generation of the heavy liquid including the emulsion breaker is limited to the heavy liquid from the second centrifugation step, it can be confirmed that the generation amount is reduced.
The amount of emulsion breaker used in Comparative Example 2 was 300 mg per 1 kg of SLOP in EW-01 and 30 mg in EW-02, and the amount used was increased compared to Example 5 in which the emulsion breaker was added to the light liquid. .

1, 31, 100 ... Water-containing oil waste liquid (crude oil containing waste liquid)
3, 43, 106: emulsion breaker 4, 5, 37, 44, 108: oil phase (4, 37: light liquid, 5, 44, 108: recovered oil)
6, 7, 38, 109 ... water phase (heavy liquid)
8, 9, 39, 110 ... Solid matter (sludge)
12 ... 1st centrifuge 14 ... 2nd centrifuge 36, 107 ... centrifuge 13a, 23, 42a, 105 ... pharmaceutical addition equipment 11, 16, 33, 102 ... heating equipment (11 ... heating equipment, 16, 33, 102 ... heat exchangers)

Claims (5)

A first centrifugation step of three-phase separation of the water-containing oil waste into an oil phase, an aqueous phase and a solid by centrifuging without addition of an emulsion breaker;
Adding an emulsion breaker to the oil phase separated by the first centrifugation step;
A second centrifugation step of three-phase separation of an oil phase, an aqueous phase and a solid by centrifuging the oil phase to which the emulsion breaker is added;
A method of treating water-containing oil waste liquid, comprising:   The method according to claim 1, wherein the emulsion breaker contains an alkylphenol condensate. A first centrifuge for three-phase separation of water-containing oil waste into an oil phase, an aqueous phase and a solid;
A drug addition facility for adding an emulsion breaker to the oil phase separated by the first centrifuge;
A second centrifuge that separates the oil phase, to which the emulsion breaker is added, into three phases, an oil phase, an aqueous phase, and a solid;
A treatment facility for water-containing oil waste liquid comprising: A centrifugal separator which separates the water-containing oil waste into three phases, an oil phase, an aqueous phase and a solid;
A drug addition facility for adding an emulsion breaker to the oil phase separated by the centrifuge;
An oil storage facility for storing the oil phase to which the emulsion breaker has been added;
A first flow path for supplying water-containing oil waste to be treated to the centrifuge without adding an emulsion breaker;
And a second flow path for supplying the oil phase, to which the emulsion breaker stored in the oil storage facility is added, to the centrifuge.
An apparatus for treating water-containing oil waste liquid, comprising: a channel switching means capable of switching between the first channel and the second channel. The treatment facility for water-containing oil waste fluid according to claim 3 or 4, further comprising a heating facility for heating the water-containing oil waste fluid to be treated.

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