Liquid separation system and liquid separation method

Abstract

[Problem] To provide a liquid separation system capable of further precisely separating undiluted solution into light fluid and heavy fluid. [Solution] A liquid separation system 1 includes: a centrifugal separator 2 for separating undiluted solution US containing light fluid and heavy fluid into first fluid LF1 mainly composed of the light fluid and second fluid HF1 mainly composed of the heavy fluid; a coalescer filter 3 to which separation solution SS1 composed of the first fluid LF1 or the second fluid HF1 is supplied; and a housing 5 for storing the coalescer filter 3. The coalescer filter 3 is configured so that minute heavy fluid or minute light fluid remaining in the separation solution SS1 is grown to coarse liquid droplets, and the coarse liquid droplets are settled or floated, and thus a light fluid layer LF2 mainly composed of the light fluid and a heavy liquid layer HF2 mainly composed of the heavy fluid are formed in the housing 5.

Description

Liquid separation system and liquid separation method

[0001] The present invention relates to a liquid separation system and a liquid separation method.

[0002] Generally, a centrifugal separator as described in Patent Document 1 is known as an apparatus for separating a raw liquid containing a light liquid such as oil and a heavy liquid such as water into the light liquid and the heavy liquid.

[0003] A characteristic of the centrifuge described in Patent Document 1 is that the larger the particles, the larger the centrifugal force acting on them, and the easier it is to separate large particles, coarse particles, particles with a large mass, and liquid droplets.

[0004] JP 2011-255257 A

[0005] However, in a centrifuge such as that described in Patent Document 1, when separating the raw liquid into a light liquid and a heavy liquid more precisely, the centrifugal force acting on the fine particles and droplets present in the raw liquid, which are small in mass, is weaker, so there is a problem that the centrifuge cannot capture them all and they end up flowing out to the downstream side.

[0006] An object of the present invention is to provide a liquid separation system and a liquid separation method that can solve the above-mentioned problems and separate a raw liquid into a light liquid and a heavy liquid more precisely.

[0007] In order to solve the above problems, the first liquid separation system of the present invention comprises a centrifuge that separates a raw liquid containing a light liquid and a heavy liquid into a first liquid mainly composed of the light liquid and a second liquid mainly composed of the heavy liquid; a coalescer filter to which a separation liquid composed of the first liquid is supplied; and a housing that houses the coalescer filter, wherein the coalescer filter captures and coagulates fine particles of heavy liquid or light liquid remaining in the separation liquid, causing them to grow into coarse droplets, and the coarse droplets sink or float within the housing due to the difference in specific gravity between them and the light liquid, thereby forming a light liquid layer mainly composed of the light liquid and a heavy liquid layer mainly composed of the heavy liquid within the housing.

[0008] The second liquid separation system comprises a centrifuge that separates a raw liquid containing a light liquid and a heavy liquid into a first liquid mainly composed of the light liquid and a second liquid mainly composed of the heavy liquid; a coalescer filter to which a separation liquid composed of the second liquid is supplied; and a housing that houses the coalescer filter, wherein the coalescer filter captures and agglomerates fine light liquid particles remaining in the separation liquid, causing them to grow into coarse droplets, and the coarse droplets float up within the housing due to the difference in specific gravity between them and the heavy liquid, thereby forming a light liquid layer mainly composed of the light liquid and a heavy liquid layer mainly composed of the heavy liquid within the housing.

[0009] The liquid separation method of the present invention includes the following steps: a first step of supplying a raw liquid containing a heavy liquid and a light liquid to a centrifuge and separating the liquid into a first liquid mainly composed of the light liquid and a second liquid mainly composed of the heavy liquid; a second step of supplying a separated liquid composed of the first liquid or the second liquid to a coalescer filter; a third step of growing fine heavy liquid or fine light liquid particles remaining in the separated liquid into coarse droplets; and a fourth step of separating the coarse droplets into a heavy liquid layer mainly composed of the heavy liquid and a light liquid layer mainly composed of the light liquid by settling or floating the coarse droplets.

[0010] The liquid separation system and method of the present invention can separate the raw liquid into a light liquid and a heavy liquid more precisely.

[0011] FIG. 1 is a schematic diagram showing a liquid separation system and a liquid separation method according to a first embodiment. FIG. 1 is a schematic diagram of a filter unit containing a coalescer filter within a housing. FIG. 1 is a schematic diagram showing a separation liquid being supplied to the filter unit and forming coarse droplets of a heavy liquid outside the coalescer filter. FIG. 1 is a schematic diagram showing a separation liquid being supplied to the filter unit and forming coarse droplets of a heavy liquid outside the coalescer filter. FIG. 2 is a schematic diagram showing a heavy liquid layer and a light liquid layer being formed within a housing. FIG. 2 is a process diagram of a liquid separation method according to a first embodiment. FIG. 3 is a schematic diagram showing a liquid separation system and a liquid separation method according to a second embodiment. FIG. 4 is a schematic diagram showing a separation liquid being supplied to a water-repellent filter unit according to a second embodiment and removing moisture as water droplets. FIG. 3 is a schematic diagram showing a liquid separation system and a liquid separation method according to a third embodiment. FIG. 4 is a schematic diagram showing a liquid separation system and a liquid separation method according to a fourth embodiment. FIG. 5 is a schematic diagram showing a liquid separation system and a liquid separation method according to a fifth embodiment. FIG. 6 is a schematic diagram showing a liquid separation system and a liquid separation method according to a sixth embodiment.

[0012] [First Embodiment] A liquid separation system 1 and a liquid separation method according to a first embodiment of the present invention will be described in detail with reference to Figure 1 and Figures 2A to 2E. Figure 1 is a schematic diagram showing the liquid separation system 1 and liquid separation method according to the first embodiment, illustrating the case where a stock liquid US containing a heavy liquid in a light liquid is separated using the liquid separation system 1. Figure 2A is a schematic diagram of a filter unit 50 containing a coalescer filter 3 within a housing 5. In the following description, the up and down directions in Figures 1 and 2A to 2D refer to the vertical direction perpendicular to the top surface of the housing 5 of the coalescer filter 3.

[0013] Liquid Separation System As shown in FIG. 1 , the liquid separation system 1 is an apparatus that separates an undiluted solution US (hereinafter referred to as "US") containing a light liquid and a heavy liquid into a light liquid and a heavy liquid. The liquid separation system 1 includes a centrifuge 2, an undiluted solution supply pipe 22, a separated light liquid supply pipe 23, a separated heavy liquid outlet pipe 24, a coalescer filter 3, a housing 5, a return flow path 33, and a discharge pipe 34.

[0014] Concentrate US is a liquid containing a light liquid with a light specific gravity and a heavy liquid with a heavier specific gravity than the light liquid. Light liquids include oils such as kerosene, diesel, aviation fuel, and gasoline. Heavy liquids include water, which has a heavier specific gravity than oils.

[0015] <First Liquid and Second Liquid> The first liquid LF1 (Light Fluids 1 (hereinafter referred to as "LF1")) and the second liquid HF1 (Heavy Fluids 1 (hereinafter referred to as "HF1")) are liquids separated from the raw liquid US by the centrifuge 2. The first liquid LF1 is a liquid mainly composed of a light liquid, and is a liquid with a light specific gravity that collects near the rotation axis when the raw liquid US is centrifuged in the centrifuge 2. The proportion of light liquid in the first liquid LF1 is, for example, 90% or more. The second liquid HF1 is a liquid mainly composed of a heavy liquid, and is a liquid with a heavy specific gravity that collects at a position far from the rotation axis when the raw liquid US is centrifuged in the centrifuge 2. The proportion of heavy liquid in the second liquid HF1 is, for example, 90% or more.

[0016] Here, examples of the main liquids that will be sequentially described in this embodiment are given. The "raw liquid US" refers to the liquid to be separated, containing a light liquid with a low specific gravity and a heavy liquid with a higher specific gravity than the light liquid. The "first liquid LF1" refers to a liquid primarily composed of a light liquid LL, which is a light liquid that collects near the rotation axis of the centrifuge 2 when the raw liquid US is centrifuged in the centrifuge 2 (see FIG. 1). The "second liquid HF1" refers to a liquid primarily composed of a heavy liquid MD, which is a heavy liquid that collects farther from the rotation axis of the centrifuge 2 when the raw liquid US is centrifuged in the centrifuge 2 (see FIG. 1). The "separated liquid SS1" refers to the liquid composed of the first liquid LF1 separated from the raw liquid US by the centrifuge 2 (see FIG. 1). The "light liquid LL" refers to the liquid that is separated from the separated liquid SS1 within the housing 5, which will be described later, and that becomes the main liquid of the light liquid layer LF2. "Heavy liquid MD" refers to the liquid that is separated from the separation liquid SS1 within the housing 5 described below and that becomes the main component of the heavy liquid layer HF2. "Fine heavy liquid MD1" refers to fine heavy liquid dispersed within the separation liquid SS1, as described below. "Coarse-grained heavy liquid MD2" refers to heavy liquid that has been coarsened by the aggregation of heavy liquid MD1, as described below.

[0017] Centrifuge 2 separates the stock solution US into a first liquid LF1 and a second liquid HF1 by using centrifugal force generated by a rotating rotor (not shown). As shown in FIG. 1, the centrifuge 2 is, for example, a plate-stacked centrifuge incorporating a pump (not shown). When the stock solution US is supplied into the centrifuge 2, the first liquid LF1, which has a lighter specific gravity, collects on the rotating shaft side, and the second liquid HF1, which has a heavier specific gravity, collects on the outer periphery side. The centrifuge 2 is configured to include a casing 21, a rotor (not shown), and a pump (not shown).

[0018] <Casing> As shown in Fig. 1, the casing 21 is a member that forms the entire outer frame of the centrifuge 2. The casing 21 is formed with a supply port 21a, a separated heavy liquid discharge port 21b, and a separated light liquid discharge port 21c. Note that the centrifuge 2 in Fig. 1 is a schematic representation, and the positions of the supply port 21a, the separated heavy liquid discharge port 21b, and the separated light liquid discharge port 21c are not limited to those shown in the figure.

[0019] The supply port 21a is an inlet for the raw liquid US. A raw liquid supply pipe 22 is connected to the supply port 21a. The separated heavy liquid discharge port 21b is an outlet for the second liquid HF1. ​​A separated heavy liquid outlet pipe 24 is connected to the separated heavy liquid discharge port 21b. The separated light liquid discharge port 21c is an outlet for the first liquid LF1. A separated light liquid supply pipe 23 is connected to the separated light liquid discharge port 21c.

[0020] 1, the stock solution supply pipe 22 is a stock solution supply flow path for supplying the stock solution US from a supply source (not shown) to the centrifuge 2. The downstream side of the stock solution supply pipe 22 is connected to the supply port 21 a of the centrifuge 2.

[0021] 1, the separated light liquid supply pipe 23 is a light liquid supply flow path for supplying the separated liquid SS1 made up of the first liquid LF1 separated from the raw liquid US by the centrifuge 2 to the coalescer filter 3. The separated light liquid supply pipe 23 is connected on its upstream side to the separated light liquid discharge port 21c, and as shown in FIG. 2A, on its downstream side is inserted into the coalescer filter 3 as internal piping section 23-1.

[0022] The separated liquid SS1 is pressurized by an impeller built into the centrifuge 2 and transferred via the separated light liquid supply pipe 23. When the separated liquid SS1 overflows from the centrifuge 2, it may be temporarily stored in a tank or the like and then transferred by a separate pump.

[0023] A plurality of through holes 23a are formed in an internal piping section 23-1 of the separated light liquid supply pipe 23 that is inserted into the coalescer filter 3, and the separated liquid SS1 supplied to the separated light liquid supply pipe 23 is discharged from the through holes 23a and supplied into the coalescer filter 3. The lower end of the separated light liquid supply pipe 23 is closed by a plug member 231, and the plug member 231 and the filter support member 31B are screwed together with bolts 232 to fix the separated light liquid supply pipe 23 and the coalescer filter 3.

[0024] 1, the separated heavy liquid outlet pipe 24 is a separated heavy liquid outlet flow path for discharging the second liquid HF1 separated from the raw liquid US by the centrifuge 2. The upstream side of the separated heavy liquid outlet pipe 24 is connected to the separated heavy liquid discharge port 21b of the centrifuge 2.

[0025] If the stock solution US contains solids, the solids are separated into solid and liquid by the centrifuge 2 and discharged separately from a discharge pipe (not shown) separate from the separated heavy liquid outlet pipe 24. In this embodiment, the centrifuge 2 is disposed upstream of the coalescer filter 3, so that the solids in the stock solution US are removed before they reach the coalescer filter 3, preventing clogging of the coalescer filter 3.

[0026] <Coalescer filter> As shown in Fig. 1, the coalescer filter 3 is a filter that can separate, for example, an oil-water mixture containing water into oil and water. As shown in Fig. 2A, the coalescer filter 3 includes a hollow filter material 30, filter support members 31 (31A, 31B) provided above and below the filter material 30, and gaskets 32 (32A, 32B) provided between the filter material 30 and the filter support members 31A, 31B, respectively.

[0027] As shown in Figures 2B and 2C, the separated liquid SS1 supplied by the separated light liquid supply pipe 23 is discharged from inside the separated light liquid supply pipe 23 toward the coalescer filter 3 located outside the pipe through a through hole 23a provided in the internal piping section 23-1 within the coalescer filter 3 of the separated light liquid supply pipe 23.

[0028] 2B and 2C, the separated liquid SS1 is pumped through the separated light liquid supply pipe 23 to the inside (center) of the coalescer filter 3. As the separated liquid SS1 travels from the inside to the outside of the filter material 30 of the coalescer filter 3, the fine heavy liquid (free water droplets) MD1 dispersed in the separated liquid SS1 are captured by the capturing action of the coalescer filter 3, causing the fine heavy liquid MD1 to aggregate and grow into coarse heavy liquid MD2. This causes the coarse heavy liquid MD2 to be separated from the separated liquid SS1.

[0029] In this embodiment, the majority of the separation liquid SS1 is the light liquid LL. As a result, as shown in Figure 2D, the separated coarse droplets (heavy liquid MD droplets in this embodiment) of the coarse heavy liquid MD2 settle in the light liquid layer LF2 outside the coalescer filter 3 due to the difference in specific gravity with the light liquid LL, and form a heavy liquid layer HF2 by accumulating at the bottom of the housing 5. The light liquid LL after separating the coarse droplets accumulates in the upper part of the housing 5, forming a light liquid layer LF2.

[0030] In this way, the coalescer filter 3 can more reliably separate the separated liquid SS (first liquid LF1 mainly composed of light liquid in this embodiment) discharged from the centrifuge 2 into light liquid and heavy liquid.

[0031] As shown in Figure 2D, the separated liquid SS1 introduced into the coalescer filter 3 is separated into a light liquid layer LF2 mainly composed of a light liquid LL and a heavy liquid layer HF2 mainly composed of a heavy liquid MD inside the housing 5. Then, the first liquid (light liquid) L １ is sent out from the upper part of the housing 5 to the discharge pipe 34. On the other hand, the second liquid (heavy liquid) L ２is discharged from a return flow path 33 provided in the lower part of the housing 5. Note that the boundary line BL illustrates the boundary between the heavy liquid layer HF2 and the light liquid layer LF2.

[0032] 1 and 2A, the housing 5 is a tank-shaped sealed container that contains the coalescer filter 3, the light liquid LL, and the heavy liquid MD. Within the housing 5, the coarse-grained heavy liquid MD2 separated by the coalescer filter 3 settles due to the difference in specific gravity with the light liquid LL, while the light liquid LL from which the coarse-grained heavy liquid MD2 has been separated floats. As a result, a light liquid layer LF2 mainly composed of the light liquid LL and a heavy liquid layer HF2 mainly composed of the heavy liquid MD are formed within the housing 5.

[0033] 2A, the housing 5 is configured to include a cylindrical body 51, a lid portion (upper flange 52) provided to close the upper end of the cylindrical body 51, and a bottom portion (lower flange 53) provided to close the lower end of the cylindrical body 51. The housing 5 is formed with a heavy liquid outlet 5a to which a return flow path 33 is connected for discharging the heavy liquid MD that has settled and separated, and a light liquid outlet 5b to which a discharge pipe 34 is connected for discharging the light liquid LL that has floated and separated. The housing 5 containing the coalescer filter 3 is referred to as a filter system (filter portion 50).

[0034] 2A, the coalescer filter 3 is attached to the upper flange 52 so as to hang down via the separated light liquid supply pipe 23. The heavy liquid outlet 5a is formed in the lower flange 53 that forms the bottom surface of the housing 5. The light liquid outlet 5b is formed at a position near the upper side of the cylindrical body 51 that forms the upper side surface of the housing 5.

[0035] <Return Flow Path> As shown in FIGS. 1 and 2D , the return flow path 33 is a flow path for conveying the second liquid (heavy liquid MD) L 2 that constitutes the heavy liquid layer HF2 in the housing 5. ２ The return flow path 33 is a flow path for supplying the second liquid (heavy liquid MD) L to the upstream side of the centrifuge 2. The return flow path 33 is connected to the heavy liquid outlet 5a on the upstream side and to the raw liquid supply pipe 22 on the downstream side. ２ is mixed with the stock solution US and reintroduced into the centrifuge 2.

[0036] 1 and 2D, the discharge pipe 34 is a flow path for discharging the liquid constituting the light liquid layer LF2 in the casing 5 to the outside of the casing 5. The upstream side of the discharge pipe 34 is connected to the light liquid outlet 5b. Therefore, the discharge pipe 34 can discharge from the casing 5 only the light liquid LL of the light liquid layer LF2 that has been separated by flotation within the casing 5, out of the first liquid LF1 centrifuged in the centrifuge 2.

[0037] <<Operation>> Next, the operation of the liquid separation system 1 and the liquid separation method according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2A to 2E.

[0038] 2E is a process diagram of the liquid separation method according to the first embodiment. First, as shown in FIG. 2E, a stock solution US containing a heavy liquid and a light liquid is supplied to a centrifuge 2 from a stock solution supply pipe 22. The stock solution US supplied to the centrifuge 2 is centrifuged within the centrifuge 2 to separate a first liquid LF1 mainly composed of the light liquid and a second liquid HF1 mainly composed of the heavy liquid (first step: S1).

[0039] Next, the separated liquid SS1 made of the first liquid LF1 is supplied into the coalescer filter 3 through the separated light liquid supply pipe 23 (second step: S2). In the coalescer filter 3, the fine heavy liquid MD1 remaining in the separated liquid SS1 is captured and coagulated by the coalescer filter 3, and separated from the separated liquid SS1 as coarse heavy liquid MD2 (third step: S3).

[0040] By allowing the coarsened heavy liquid MD2 separated by the coalescer filter 3 to settle inside the housing 5, the separated liquid SS1 supplied from the centrifuge 2 is separated into a heavy liquid layer HF2 mainly composed of heavy liquid MD and a light liquid layer LF2 mainly composed of light liquid LL (fourth step: S4).

[0041] Next, the second liquid (heavy liquid MD) L constituting the heavy liquid layer HF2 ２is sent to the stock solution supply pipe 22 via the return flow path 33 and mixed with the stock solution US (fifth step: S5). The liquid sent to the centrifuge 2 is then separated into the light liquid LL and the heavy liquid MD by repeating the first step (S1), second step (S2), third step (S3), fourth step (S4), and fifth step (S5).

[0042] Therefore, the heavy liquid MD consisting of water that was not completely centrifuged in the centrifuge 2 and remained in the first liquid LF1 can be further separated, and as a result, it is possible to obtain a light liquid (first liquid L1) consisting of oil that has been separated with high precision, which is the target of purification.

[0043] As an example of the present invention, the heavy liquid has been described as "water" and the light liquid as "oil," but the liquid separation system 1 of this embodiment is not limited to the heavy liquid being "water" and the light liquid being "oil." As long as the raw liquid US contains a light liquid and a heavy liquid with different specific gravities, it can be precisely separated into a light liquid and a heavy liquid.

[0044] 1, the liquid separation system 1 comprises a centrifuge 2 that separates a raw liquid US containing a light liquid LL and a heavy liquid MD into a first liquid LF1 mainly composed of the light liquid LL and a second liquid HF1 mainly composed of the heavy liquid MD, a coalescer filter 3 to which a separation liquid SS1 composed of the first liquid LF1 is supplied, and a housing 5 that houses the coalescer filter 3. The coalescer filter 3 separates minute heavy liquid MD1 remaining in the separation liquid SS1 from the separation liquid SS1, forming a light liquid layer LF2 mainly composed of the light liquid LL and a heavy liquid layer HF2 mainly composed of the heavy liquid MD within the housing 5.

[0045] The liquid separation system 1 according to this embodiment includes the coalescer filter 3, which allows for efficient and precise liquid-liquid separation by capturing, flocculating, and coarsening fine droplets that could not be separated by centrifugal separation in the centrifuge 2. This makes it possible to precisely separate light liquid from heavy liquid even when a model with a small rated throughput is selected as the centrifuge 2, reducing the installation space and size of the centrifuge 2, thereby reducing operating power and costs.

[0046] As shown in FIG. 1, the liquid separation system 1 separates the second liquid L 2 from the heavy liquid layer HF 2 separated by the coalescer filter 3 . ２ The apparatus further includes a return flow path 33 that returns the liquid (liquid) to the stock solution supply pipe 22 that supplies the stock solution US to the centrifuge 2.

[0047] With this configuration, the heavy liquid MD in the housing 5 can be returned to the centrifuge 2 again via the return flow path 33, and even if light liquid remains in the heavy liquid MD due to reasons such as a small difference in specific gravity between the light liquid LL and the heavy liquid MD, the light liquid and heavy liquid can be reliably separated.

[0048] As shown in FIG. 1, the liquid separation method of this embodiment includes a first step (S1) in which a raw liquid US containing a heavy liquid and a light liquid is supplied to a centrifuge 2 and separated into a first liquid LF1 mainly composed of light liquid and a second liquid HF1 mainly composed of heavy liquid; a second step (S2) in which a separated liquid SS1 composed of the first liquid LF1 is supplied to a coalescer filter 3; a third step (S3) in which the coalescer filter 3 captures and aggregates fine heavy liquid MD1 remaining in the separated liquid SS1, causing them to grow into coarse droplets MD2; and a fourth step (S4) in which the coarse droplets MD2 are separated into a heavy liquid layer HF2 mainly composed of heavy liquid MD and a light liquid layer LF2 mainly composed of light liquid LL by settling them due to the difference in specific gravity between them and the light liquid LL.

[0049] That is, in the liquid separation method of this embodiment, the light liquid LL and heavy liquid MD contained in the separated liquid SS1 discharged from the centrifuge 2 are further separated by the coalescer filter 3, so that separation into the heavy liquid and the light liquid can be reliably achieved.

[0050] In the liquid separation method of this embodiment, the liquid constituting the heavy liquid layer HF2 is mixed with the raw liquid US on the upstream side of the centrifugal separator 2, as shown in FIG.

[0051] According to this configuration, the heavy liquid MD in the heavy liquid layer HF2 is returned to and mixed with the raw liquid US, and is subjected to centrifugal force in the centrifuge 2, becoming contained in the second liquid HF1.

[0052] [Second Embodiment] Next, a liquid separation system 1A and a liquid separation method according to a second embodiment will be described with reference to Figures 3A and 3B, focusing on the differences from the liquid separation system 1 (see Figure 1) and liquid separation method according to the first embodiment. Components already described will be assigned the same reference numerals and descriptions thereof will be omitted. Figure 3A is a schematic diagram showing the liquid separation system 1A and liquid separation method according to the second embodiment.

[0053] As shown in Figure 3A, the liquid separation system 1A according to the second embodiment differs from the first embodiment in that a water-repellent filter 4 having water-repellent properties is housed within the housing 5A of the filter section 50A.

[0054] The liquid separation system 1A according to the second embodiment includes a coalescer filter 3 and a water-repellent filter 4 disposed to the side of the coalescer filter 3 within a housing 5A of a filter unit 50A. The coalescer filter 3 and the water-repellent filter 4 are installed so as to hang down from the lid (upper flange 52A) of the housing 5A. The coalescer filter 3 is disposed around a supply pipe (separated light liquid supply pipe 23) that penetrates the lid (upper flange 52A) of the housing 5A and is inserted into the interior of the housing 5A. The water-repellent filter 4 is disposed around a discharge pipe 34A that penetrates the lid (upper flange 52A) of the housing 5A and is inserted into the interior of the housing 5A, and that discharges the liquid separated by the water-repellent filter 4. The return flow path 33 is connected to the lower part of the housing 5A.

[0055] The housing 5A is configured to include a cylindrical body 51A, a lid (upper flange 52A) provided to close the upper end of the cylindrical body 51A, and a bottom (lower flange 53A) provided to close the lower end of the cylindrical body 51A. Inside the housing 5A, the coalescer filter 3 is housed, and on the side of the coalescer filter 3, water-repellent filters 4 are housed side by side at an appropriate interval in the horizontal direction. For this reason, the housing 5A is larger in the horizontal direction than the housing 5 shown in FIG. 1.

[0056] 3A, a heavy liquid outlet 5Aa, to which the return flow path 33 is connected, is provided in the center of a lower flange 53A that forms the bottom surface of the housing 5A. That is, the heavy liquid outlet 5Aa is located below and between the coalescer filter 3 and the water-repellent filter 4 within the housing 5A.

[0057] Within the housing 5A, the separated liquid SS1 (a liquid mainly composed of light liquid with a small amount of heavy liquid remaining) supplied from the separated light liquid supply pipe 23 is separated into light liquid LL and heavy liquid MD by the coalescer filter 3 and discharged into the housing 5A. The heavy liquid MD discharged into the housing 5A settles within the housing 5A to form a heavy liquid layer HF2, and the light liquid LL rises within the housing 5A to form a light liquid layer LF2 mainly composed of light liquid LL.

[0058] The heavy liquid of the settled and separated heavy liquid layer HF2 (second liquid L ２ ) is sent from the heavy liquid outlet 5Aa to the centrifuge 2 via the return flow path 33. Here, the heavy liquid (second liquid L) of the heavy liquid layer HF2 that has been separated and settled and contains water W and solids sent to the centrifuge 2 via the return flow path 33 is ２ ) is centrifuged again in the centrifuge 2, where the heavy liquid containing solids is separated and removed as the second liquid HF1.

[0059] A discharge pipe 34A is inserted into the water-repellent filter 4, and the light liquid that has passed through the water-repellent filter 4 is discharged through the discharge pipe 34A. In this way, the water-repellent filter 4 can suppress the intrusion of water into the light liquid and further improve the purity of the light liquid.

[0060] The liquid separation system 1A of the second embodiment has a water-repellent filter 4 inside the housing 5A, which makes it possible to remove moisture W and solids from the light liquid LL in the separated light liquid layer LF2. This increases the purity of the light liquid discharged from the housing 5A. Furthermore, because the housing 5A houses the coalescer filter 3 and the water-repellent filter 4 in a single housing 5A, it is possible to reduce assembly man-hours and the number of parts, thereby reducing costs, compared to when the coalescer filter and water-repellent filter are installed separately.

[0061] Furthermore, since the water-repellent filter 4 is arranged around the internal piping section 34A-1, which is part of the discharge pipe 34A inside the housing 5A, the light liquid LL that has been separated by floating inside the housing 5A can be further removed of moisture and solids before being discharged from the discharge pipe 34A.

[0062] That is, as shown in FIG. 3B, the moisture W is separated as droplets and falls around the water-repellent filter 4, and the light liquid LLL from which the moisture W and solids have been removed is introduced into the internal piping section 23-1 and discharged.

[0063] [Third embodiment] Next, a liquid separation system 1B and a liquid separation method according to a third embodiment will be described, focusing on differences from the liquid separation system 1 according to the first embodiment (see Figure 1), with reference to Figure 4. Figure 4 is a schematic diagram showing the liquid separation system 1B and the liquid separation method according to the third embodiment.

[0064] As shown in FIG. 4, the liquid separation system 1B according to the third embodiment differs from the first embodiment in that the stock solution US containing a light liquid and a heavy liquid has a higher ratio of heavy liquid to light liquid than the stock solution US according to the first embodiment.

[0065] In addition, the liquid separation system 1B of the third embodiment differs from the first embodiment in that the first liquid LF1, which is mainly composed of light liquid separated from the raw liquid US in the centrifuge 2, is discharged to the outside of the liquid separation system 1B from the separated light liquid outlet pipe 26.

[0066] The liquid separation system 1B of the third embodiment also differs from the first embodiment in that the second liquid HF1 (a liquid mainly composed of heavy liquid and containing a trace amount of light liquid) separated from the raw liquid US by the centrifuge 2 is supplied as separated liquid SS2 from the separated heavy liquid supply pipe 25 to the interior (center) of the coalescer filter 3. The coalescer filter 3 separates the heavy liquid from the separated liquid SS2 by capturing and agglomerating the fine light liquid particles in the separated liquid SS2 supplied from the centrifuge 2 and growing them into coarse droplets. The coarse droplets (light liquid) that have flowed out to the outside of the coalescer filter 3 float within the housing 5B due to the difference in specific gravity between them and the heavy liquid, and can be separated within the housing 5B into a heavy liquid layer HF2 mainly composed of heavy liquid and a light liquid layer LF2 mainly composed of light liquid.

[0067] In addition, the liquid separation system 1B of the third embodiment separates the light liquid LL of the light liquid layer LF2 that has been separated by floating in the housing 5B of the filter unit 50B into the first liquid L. １ The second embodiment differs from the first embodiment in that the raw liquid is returned from the return flow path 33B to the raw liquid supply pipe 22 on the upstream side of the centrifuge 2.

[0068] In addition, the liquid separation system 1B of the third embodiment separates the heavy liquid MD (second liquid L) of the heavy liquid layer HF2 that has settled and separated in the housing 5 of the filter unit 50B. ２ ) is discharged to the outside of the liquid separation system 1B from a discharge pipe 34B provided at the bottom of the housing 5B. By providing the discharge pipe 34B at the inner bottom of the housing 5B in this way, it becomes difficult for the light liquid to be mixed with the heavy liquid discharged from inside the housing 5B.

[0069] 4, the liquid separation system 1B includes a centrifuge 2 that separates a raw liquid US containing a light liquid and a heavy liquid into a first liquid LF1 mainly composed of light liquid and a second liquid HF1 mainly composed of heavy liquid, a coalescer filter 3 to which a separation liquid SS2 composed of the second liquid HF1 is supplied, and a housing 5B that houses the coalescer filter 3. The coalescer filter 3 separates the heavy liquid from the separation liquid SS2 by capturing and agglomerating minute amounts of light liquid remaining in the separation liquid SS2 and growing them into coarse droplets, and the coarse droplets float up within the housing 5B due to the difference in specific gravity between the heavy liquid and the light liquid (coarse droplets), forming a light liquid layer LF2 mainly composed of light liquid and a heavy liquid layer HF2 mainly composed of heavy liquid within the housing 5B.

[0070] According to the liquid separation system 1B, the separated liquid SS2 (liquid mainly consisting of heavy liquid and containing a small amount of light liquid) discharged from the centrifuge 2 can be separated into light liquid and heavy liquid more precisely.

[0071] 4, the liquid separation system 1B further includes a return flow path 33B that returns the first liquid L1 (liquid) that constitutes the light liquid layer LF2 separated by the coalescer filter 3 to the raw liquid supply pipe 22 that supplies the raw liquid US to the centrifuge 2. The return flow path 33B is connected to the upper part of the cylindrical body 51B or to the upper flange 52B.

[0072] According to this configuration, the liquid constituting the light liquid layer LF2 can be returned to the centrifuge 2. The light liquid LL in the light liquid layer LF2 is mixed with the raw liquid US in a coarse state, and therefore becomes contained in the first liquid LF1 during the process of centrifugation in the centrifuge 2.

[0073] [Fourth embodiment] Next, a liquid separation system 1C and a liquid separation method according to a fourth embodiment will be described with reference to Fig. 5, focusing on the differences from the liquid separation system 1A according to the second embodiment (see Fig. 3). Fig. 5 is a schematic diagram showing the liquid separation system 1C and the liquid separation method according to the fourth embodiment.

[0074] As shown in Figure 5, the liquid separation system 1C of the fourth embodiment differs from the second embodiment in that the stock solution US containing a light liquid and a heavy liquid has a higher ratio of heavy liquid to light liquid than the stock solution US of the second actual embodiment.

[0075] In addition, the liquid separation system 1C of the fourth embodiment differs from the second embodiment in that the first liquid LF1 (a liquid mainly composed of light liquid and containing a small amount of heavy liquid) separated from the raw liquid US by the centrifuge 2 is discharged outside the liquid separation system 1B from the separated light liquid outlet pipe 26.

[0076] The liquid separation system 1C of the fourth embodiment also differs from the second embodiment in that the second liquid HF1 (a liquid mainly composed of heavy liquid and containing a trace amount of light liquid) separated from the raw liquid US by the centrifuge 2 is supplied to the inside of the coalescer filter 3 through the separated heavy liquid supply pipe 25 as the separated liquid SS2.

[0077] In addition, the liquid separation system 1C of the fourth embodiment differs from the second embodiment in that the light liquid LL of the light liquid layer LF2 that has been separated and floated within the housing 5C of the filter section 50C is returned from the return flow path 33C to the raw liquid supply pipe 22 upstream of the centrifuge 2.

[0078] The liquid separation system 1C according to the fourth embodiment also differs from the second embodiment in that it includes an oil-repellent filter 6. As shown in FIG. 5 , a coalescer filter 3 is attached to the lid (upper flange 52C) of the housing 5C so as to hang down, and an oil-repellent filter 6 is attached to the bottom (lower flange 53C) of the housing 5C. The coalescer filter 3 is disposed around the internal piping section 25-1 of the supply pipe (heavy liquid separation supply pipe 25) that penetrates the lid (upper flange 52C) of the housing 5C and is inserted into the housing 5C. The oil-repellent filter 6 is disposed around the internal piping section 34A-1 of the discharge pipe 34A that penetrates the lid (upper flange 52C) of the housing 5C and is inserted into the housing 5C, and that discharges the liquid separated by the oil-repellent filter 6. The return flow path 33C is connected to the top of the cylindrical body 51C or the upper flange 52C.

[0079] According to the liquid separation system 1C, the oil-repellent filter 6 in the housing 5C of the filter unit 50C can remove oil and solids from the heavy liquid in the heavy liquid layer HF2 that has settled and separated. This increases the purity of the heavy liquid discharged from the discharge pipe 34C of the housing 5C. Furthermore, because the housing 5C houses the coalescer filter 3 and the oil-repellent filter 6 in a single housing 5C, the assembly time and number of parts can be reduced, thereby reducing costs, compared to when the coalescer filter and oil-repellent filter are installed separately.

[0080] According to the liquid separation system 1C, the light liquid LL separated by floating is separated into the first liquid L １ The light liquid in the light liquid layer LF2 is mixed with the raw liquid US in a coarse state, and is therefore contained in the first liquid LF1 during the process of centrifugation in the centrifuge 2.

[0081] Fifth Embodiment Next, a liquid separation system and a liquid separation method according to a fifth embodiment will be described with reference to Fig. 6. Fig. 5 is a schematic diagram showing the configuration of a liquid separation system and a liquid separation method according to the fifth embodiment, and is a vertical cross-sectional view of the center of a filter unit 50D.

[0082] In the filter unit 50A shown in FIG. 3, the water-repellent filter 4 is disposed to the side of the coalescer filter 3. However, in this embodiment, as shown in FIG. 5, it is preferable to dispose the water-repellent filter 4 and the coalescer filter 3 in a housing 5D that is long in the vertical direction, and to dispose the water-repellent filter 4 above the coalescer filter 3.

[0083] The separated light liquid supply pipe 23 passes through the lower flange 53D of the housing 5D and is inserted into the coalescer filter 3. The upper open end of the separated light liquid supply pipe 23 is closed with a plug member 231, and the separated light liquid supply pipe 23 and the coalescer filter 3 are fixed together by screwing the plug member 231 and the filter support member 31A together with bolts 232. A plurality of through holes 23a are formed in the internal piping section 23-1 of the portion of the separated light liquid supply pipe 23 that is inserted into the coalescer filter 3, and the separated liquid SS1 supplied by the separated light liquid supply pipe 23 is discharged from inside the separated light liquid supply pipe 23 through the through holes 23a toward the coalescer filter 3 located outside the pipe. The coalescer filter 3 includes a cylindrical filter material 30, filter support members 31 (31A, 31B) disposed above and below the filter material 30, and packings 32 (32A, 32B) interposed between the end faces of the filter material 30 and the filter support members 31 (31A, 31B). The filter material 30 is sandwiched between the filter support members 31 (31A, 31B) disposed above and below the filter material 30.

[0084] The housing 5D includes a vertically long cylindrical body 51D, an upper flange 52D provided to close the upper opening of the cylindrical body 51D, and a lower flange 53D provided to close the lower opening of the cylindrical body 51D. The cylindrical body 51D houses a coalescer filter 3 and a water-repellent filter 4. The coalescer filter 3 is housed in the lower part of the cylindrical body 51D, and the water-repellent filter 4 is housed in the upper part of the cylindrical body 51D. A discharge pipe 34 is inserted into the upper flange 52D. A separated light liquid supply pipe 23 and a return flow path 33 are inserted into the lower flange 53D.

[0085] The discharge pipe 34 penetrates the upper flange 52D of the housing 5D and is inserted into the water-repellent filter 4. The lower open end of the discharge pipe 34 is closed with a plug member 341, and the discharge pipe 34 and the water-repellent filter 4 are fixed together by screwing the plug member 341 and the filter support member 31B together with bolts 342. The light liquid LL in the light liquid layer LF2 inside the housing 5D that has passed through the coalescer filter 3 passes through the water-repellent filter 4 and is discharged from the discharge pipe 34 via a through-hole 34a provided in the internal piping portion 34-1 inside the water-repellent filter 3 of the discharge pipe 34.

[0086] The water-repellent filter 4 includes a cylindrical filter material 40, filter support members 41 (41A, 41B) disposed above and below the filter material 40, and gaskets 42 (42A, 42B) disposed between the end faces of the filter material 40 and the filter support members 41 (41A, 41B). The filter material 40 is sandwiched between the filter support members 41 (41A, 41B) disposed above and below the filter material 40. The discharge pipe 34 and the water-repellent filter 4 are fixed by threading a bolt 342 passing through the filter support member 41B onto a plug member 341 of the discharge pipe 34 inserted into the water-repellent filter 4.

[0087] 6 includes, within a housing 5D, a coalescer filter 3 and a water-repellent filter 4 disposed above the coalescer filter 3 in the liquid flow direction. The coalescer filter 3 is disposed around a supply pipe (separated light liquid supply pipe 23) that penetrates the bottom (lower flange 53D) of the housing 5D and is inserted into the housing 5D. The water-repellent filter 4 is disposed around a discharge pipe 34 that penetrates the lid (upper flange 52D) of the housing 5D and is inserted into the housing 5D, and that discharges the liquid separated in the water-repellent filter 4. The return flow path 33 is connected to the bottom (lower flange 53D) of the housing 5D.

[0088] According to this configuration, the housing 5D can be made long in the vertical direction, as shown in Fig. 6. Therefore, the installation area of ​​the housing 5D can be reduced, and the entire filter unit 50D can be made smaller.

[0089] Sixth Embodiment Next, a liquid separation system and a liquid separation method according to a sixth embodiment will be described with reference to Fig. 7. Fig. 7 is a schematic diagram showing the configuration of a liquid separation system and a liquid separation method according to the sixth embodiment, and is a vertical cross-sectional view of the center of a filter unit 50E.

[0090] As shown in FIG. 7, a filter unit 50E may have an oil-repellent filter 6 disposed below the coalescer filter 3 in the liquid flow direction within a housing 5E.

[0091] The separated light liquid supply pipe 23E penetrates the upper flange 52E and is inserted into the coalescer filter 3. The lower open end of the separated light liquid supply pipe 23E is closed with a plug member 231, and the separated light liquid supply pipe 23E and the coalescer filter 3 are fixed together by screwing the plug member 231 and the filter support member 31B together with bolts 232. A plurality of through holes 23Ea are formed in the internal piping section 23E-1 of the portion of the separated light liquid supply pipe 23E that is inserted into the coalescer filter 3, and the separated liquid SS2 supplied by the separated light liquid supply pipe 23E is discharged from inside the separated light liquid supply pipe 23E through the through holes 23Ea toward the coalescer filter 3 located outside the pipe.

[0092] The housing 5E includes a cylindrical body 51E that is long in the vertical direction, an upper flange 52E that closes the upper opening of the cylindrical body 51E, and a lower flange 53E that closes the lower opening of the cylindrical body 51E. A coalescer filter 3 and an oil-repellent filter 6 are housed within the cylindrical body 51E. The coalescer filter 3 is housed in the upper portion of the cylindrical body 51E, and the oil-repellent filter 6 is housed in the lower portion of the cylindrical body 51E. A separated light liquid supply pipe 23E and a return flow path 33 are inserted into the upper flange 52E. A discharge pipe 34E is inserted into the lower flange 53E.

[0093] The discharge pipe 34E penetrates the lower flange 53E and is inserted into the oil-repellent filter 6. The upper open end of the discharge pipe 34E is closed with a plug member 342, and the discharge pipe 34E and the oil-repellent filter 6 are fixed together by screwing the plug member 342 and the filter support member 61A together with bolts 342. A plurality of through holes 34Ea are formed in the internal piping section 23E-1 of the portion of the discharge pipe 34E that is inserted into the oil-repellent filter 6, and the heavy liquid MD in the heavy liquid layer HF2 in the housing 5D that has passed through the coalescer filter 3 passes through the water-repellent filter 6 and is then discharged from the discharge pipe 34 via the through holes 34Ea.

[0094] The oil-repellent filter 6 includes a cylindrical filter material 60, filter support members 61 (61A, 61B) disposed above and below the filter material 60, and gaskets 62 (62A, 62B) disposed between the end faces of the filter material 60 and the filter support members 61 (61A, 61B). The filter material 60 is sandwiched between the filter support members 61 (61A, 61B) disposed above and below the filter material 60. The discharge pipe 34E and the oil-repellent filter 6 are fixed by threading a bolt 342 passing through the filter support member 61A onto a plug member 341 of the discharge pipe 34E inserted into the oil-repellent filter 6.

[0095] 7 includes, within a housing 5E, a coalescer filter 3 and an oil-repellent filter 6 disposed above the coalescer filter 3 in the liquid flow direction. The coalescer filter 3 is disposed around a supply pipe (separated light liquid supply pipe 23E) that penetrates the lid (upper flange 52E) of the housing 5E and is inserted into the housing 5E. The oil-repellent filter 6 is disposed around a discharge pipe 34E that penetrates the lid (lower flange 53E) of the housing 5E and is inserted into the housing 5E, and that discharges the liquid separated in the oil-repellent filter 6. The return flow path 33E is connected to the bottom of the housing 5E.

[0096] 7, the housing 5E of the filter unit 50E can be made long in the vertical direction by disposing the oil-repellent filter 6 inside the housing 5E below the coalescer filter 3. This allows the installation area of ​​the housing 5E to be reduced, thereby enabling the overall size of the filter unit 50E to be reduced.

[0097] [Modifications] The present invention is not limited to the first to sixth embodiments, and various modifications and changes are possible within the scope of the technical concept thereof, and the present invention naturally extends to these modified and changed inventions. For example, in the liquid separation systems 1, 1A, 1B, and 1C of the first to fourth embodiments, the use of one centrifuge 2 has been described, but multiple centrifuges 2 may be installed and the raw liquid US may be centrifuged multiple times.

[0098] In the second embodiment shown in FIG. 3, one coalescer filter 3 and one water-repellent filter 4 are arranged at appropriate intervals in the horizontal direction within the housing 5A, but multiple copies of either filter may be provided.

[0099] Furthermore, when the housings 5A, 5C are large, the number of coalescer filters 3 and water-repellent filters 4 shown in Fig. 3 may be increased appropriately to match the size of the housings 5A, 5C. To increase the number of coalescer filters 3, the separated light liquid supply pipe 23 and separated heavy liquid supply pipe 25 shown in Figs. 2 and 4 may be made into multiple pipes or may be branched on the downstream side, and a coalescer filter 3 may be provided in each downstream portion.

[0100] The housing 5 may also be provided with a bubble generator for generating bubbles in the separated liquids SS1 and SS2 supplied from the centrifuge 2, and a filter for removing the bubbles generated by the bubble generator. This also makes it possible to separate oil and the like contained in the separated liquids SS1 and SS2.

[0101] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C Liquid separation system 2 Centrifuge 3 Coalescer filter 4 Water-repellent filter 5, 5A, 5B, 5C, 5D, 5E Housing 6 Oil-repellent filter 23, 23D Separation light liquid supply pipe (supply pipe) 25 Separation heavy liquid supply pipe (supply pipe) 33, 33B, 33C, 33E Return flow path 34, 34A, 34B, 34D, 34E Discharge pipe 50, 50A, 50B, 50C, 50D, 50E Filter portion 51, 51A, 51B, 51C, 51D, 51E Cylindrical body 52, 52A, 52B, 52C, 52D, 52E Upper flange (lid portion) 53, 53A, 53B, 53C, 53D, 53E Lower flange (bottom portion) HF1 Second liquid HF2 Heavy liquid layer LF1 First liquid LF2 Light liquid layer SS1 Separated liquid US Stock solution

Claims

a centrifuge that separates a raw liquid containing a light liquid and a heavy liquid into a first liquid mainly containing the light liquid and a second liquid mainly containing the heavy liquid; a coalescer filter to which a separation liquid comprising the first liquid is supplied; a housing that houses the coalescer filter; Equipped with The coalescer filter captures and aggregates the fine heavy liquid particles remaining in the separation liquid, thereby growing them into coarse droplets, the coarsened droplets settle within the housing due to the difference in specific gravity between them and the light liquid, thereby forming a light liquid layer mainly composed of the light liquid and a heavy liquid layer mainly composed of the heavy liquid within the housing. Liquid separation system. 　 a centrifuge that separates a raw liquid containing a light liquid and a heavy liquid into a first liquid mainly containing the light liquid and a second liquid mainly containing the heavy liquid; a coalescer filter to which a separation liquid comprising the second liquid is supplied; a housing that houses the coalescer filter; Equipped with The coalescer filter captures and aggregates the fine light liquid particles remaining in the separated liquid, thereby growing them into coarse droplets, The coarsened droplets float up in the housing due to the difference in specific gravity between them and the heavy liquid, thereby forming a light liquid layer mainly made of the light liquid and a heavy liquid layer mainly made of the heavy liquid in the housing. Liquid separation system. 　 a return flow path for returning the liquid constituting the heavy liquid layer separated by the coalescer filter to a raw liquid supply pipe for supplying the raw liquid to the centrifuge; The liquid separation system of claim 1 . 　 a return flow path for returning the liquid constituting the light liquid layer separated by the coalescer filter to a raw liquid supply pipe for supplying the raw liquid to the centrifuge; The liquid separation system of claim 2 . 　 A water-repellent filter having water-repellent properties or an oil-repellent filter having oil-repellent properties is housed in the housing. A liquid separation system according to claim 1 or 3. 　 Within the housing, the coalescer filter; and a water-repellent filter that is disposed above the coalescer filter in a liquid flow direction and has water repellency, The coalescer filter is disposed around a supply pipe that penetrates the bottom of the housing and is inserted into the housing, the water-repellent filter is inserted into the housing through a lid portion of the housing and is disposed around a discharge pipe that discharges the separated liquid from the water-repellent filter; and The return flow path is connected to the bottom of the housing. The liquid separation system of claim 3 . 　 Within the housing, The system comprises the coalescer filter 3 and an oil-repellent filter that is disposed below the coalescer filter in the liquid flow direction and has oil repellency, The coalescer filter is disposed around a supply pipe that penetrates a lid of the housing and is inserted into the housing, The oil-repellent filter is inserted into the housing through a bottom portion thereof and disposed around a discharge pipe for discharging a liquid separated from the oil-repellent filter; and The return flow path is connected to the top of the housing. The liquid separation system of claim 4. 　 Within the housing, the coalescer filter; and a water-repellent filter disposed laterally of the coalescer filter and having water repellency, The coalescer filter is disposed around a supply pipe that penetrates a lid of the housing and is inserted into the housing, the water-repellent filter is inserted into the housing through a lid portion of the housing and is disposed around a discharge pipe that discharges the separated liquid from the water-repellent filter; and The return flow path is connected to the housing. The liquid separation system of claim 3 . Within the housing, The coalescer filter and an oil-repellent filter disposed laterally of the coalescer filter and having oil repellency, The coalescer filter is disposed around a supply pipe that penetrates a lid of the housing and is inserted into the housing, The oil-repellent filter is inserted into the housing through a lid portion of the housing and is disposed around a discharge pipe that discharges the separated liquid from the oil-repellent filter; and The return flow path is connected to the housing. The liquid separation system of claim 4. 　 a first step of supplying a stock solution containing a heavy liquid and a light liquid to a centrifuge and separating the stock solution into a first liquid mainly composed of the light liquid and a second liquid mainly composed of the heavy liquid; a second step of supplying a separation liquid consisting of the first liquid or the second liquid to a coalescer filter; a third step of growing the fine heavy liquid or fine light liquid remaining in the separation liquid into coarse droplets; a fourth step of separating the coarsened droplets into a heavy liquid layer mainly composed of the heavy liquid and a light liquid layer mainly composed of the light liquid by sedimenting or floating the coarsened droplets; Including, Liquid separation method. 　 Further, a fifth step of returning the liquid constituting the heavy liquid layer or the liquid constituting the light liquid layer separated by the coalescer filter to the original liquid is included. The method for separating liquids according to claim 10.

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