JP4592934B2 - Separator plate centrifuge and method for operating the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a separator-plate centrifuge and an operation method thereof, and more specifically, a reliable and stable replacement process when discharging heavy liquid in so-called clarifier operation that separates heavy and light liquids having specific gravity close to each other. The present invention relates to a separator-plate centrifuge that can be implemented in an automated manner and an operating method thereof.
[0002]
[Prior art]
Separating plate type centrifuges, for example, process oils (hereinafter referred to as “stock solutions”) in which suspended substances and water are mixed in oils such as lubricating oils and fuel oils, and then centrifuge the sludge and water with a large specific gravity. Is separated into heavy liquid to clean oil with low specific gravity (light liquid), and is generally used for cleaning lubricating oil and fuel oil for ships and the like. The separator plate type centrifugal separator is, for example, in a state where a rotating drum having an upper end opened, a rotating body lid fitted into the upper end opening of the rotating drum to form a rotating body, and inserted into the rotating drum. A main valve that moves up and down to open and close a discharge port formed on the side of the rotating body, and a plurality of layers stacked at predetermined intervals in the vertical direction in a separation chamber formed between the main valve and the partition plate The separation liquid is centrifuged into a light liquid and a heavy liquid through the separation plate, and the light liquid and the heavy liquid separated in the separation chamber are separated. Discharge each individually.
[0003]
In recent years, marine heavy oil has become denser, and heavy oil with a specific gravity exceeding 0.991 is widely available on the market. Thus, when cleaning heavy oil with a large specific gravity, it is generally treated by clarifier operation. Clarifier operation refers to an operation method in which oil to be treated is centrifuged into two liquid phases, light liquid (heavy oil) and heavy liquid, using a separating plate centrifuge. There is a purifier operation for a clarifier operation. The purifier operation is an operation method in which the oil to be treated is centrifuged into a solid phase composed of a solid substance and two continuous liquid phases (an aqueous phase having a high specific gravity and an oil phase having a low specific gravity). In the clarifier operation, it is not necessary to adjust the specific gravity plate according to the specific gravity of the oil to be treated required in the purifier operation. Therefore, in addition to high-density heavy oil, general heavy oil or mineral oil such as lubricating oil can be used. Widely used for processing.
[0004]
By the way, in the clarifier operation, heavy components other than the sludge separated from the oil to be treated, such as separated water, cannot be continuously discharged as in the purifier operation. Therefore, the separated water separated and filled in the rotating body is intermittently discharged to the outside. However, since the rotating body is filled with a large amount of clean oil as well as separated water, a part of the clean oil may be discharged together with the separated water when the separated water is discharged. In order to prevent such a situation, there is a replacement step of supplying replacement water into the rotating body, replacing a part of the clean oil with the replacement water, and collecting the clean oil. In the conventional replacement step, when supplying replacement water, the replacement water supply time is set in advance by a timer or the like, and the replacement water is supplied for the set time.
[0005]
[Problems to be solved by the invention]
However, the replacement step performed prior to discharging the separation water (including sludge) in the rotating body of the conventional separator plate centrifuge, that is, the step of replacing a part of the cleaning oil in the rotating body with the replacement water. In this case, the preset amount of water is not always supplied depending on the pressure fluctuation on the supply side of the replacement water or the state of the piping, and the amount of water supply is not constant and may be too much or too little. is there. In addition, the same thing may cause the water supply amount to be too much or too little due to an artificial operation mistake such as a mistake in setting the water supply time. If the supply amount of the replacement water is too large, the replacement water is not sufficiently separated in the separation chamber and is mixed into the clean oil, and the moisture value rises in time series. In particular, in the case of a lubricating oil or the like that circulates and cleans the oil to be treated in the same tank, since water is particularly disliked, excessive supply of replacement water is a very serious problem. On the contrary, if the amount of replacement water supplied is too small, extra clean oil is discharged when the separated water is discharged, and the recovery rate of the clean oil decreases and the loss of recovered oil increases. This is particularly a problem in the case of fuel oil that occupies a large weight in operating costs.
[0006]
In the case of the conventional replacement process, it is common to supply replacement water while overflowing a part of the replacement water from the heavy liquid side. When precious fresh water in the ship is used as replacement water, Wastes fresh water, and the overflow water from the heavy liquid side is collected in the sludge tank or finally in the waste oil tank, which increases the amount of sludge treatment.
[0007]
The present invention has been made to solve the above-described problems, and eliminates the overflow of the replacement water from the rotating body and is not affected by the pressure fluctuation on the supply side of the replacement water, and sets the water supply time. It is an object of the present invention to provide a separation plate type centrifugal separator that can supply a certain amount of replacement water into a rotating body reliably and stably without excess or deficiency, and an operation method thereof.
[0008]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a separation plate type centrifugal separator comprising: a rotating drum having an upper end opened; a rotating member lid fitted into the upper end opening of the rotating drum to form a rotating member; and the rotating member cover A partition plate disposed through a gap, a main valve that moves up and down in a state of being inserted into the rotating drum, and opens and closes a discharge port formed in a side portion of the rotating body, and the main valve A separation chamber formed between the valve and the partition plate, and a plurality of separation plates stacked at a predetermined interval in the vertical direction, and the liquid to be treated supplied from the raw liquid supply pipe into the separation chamber The light liquid in the separation chamber is discharged to the outside through the first centripetal pump, while the heavy liquid in the separation chamber is intermittently discharged from the discharge port. A part of the light liquid in the separation chamber by supplying replacement water into the separation chamber prior to external discharge In the separation plate type centrifugal separator that replaces and collects with the replacement water, the replacement water is supplied into the rotating body through the gap between the rotating body lid and the partition plate or through the stock solution supply pipe. From the outer diameter of the second centripetal pump, or the second centripetal pump, and the second centripetal pump below the second centripetal pump for discharging the replacement water flowing through the gap between the rotating body lid and the partition plate A pressure sensor for providing a weir having a small diameter, a connecting pipe for communicating the second centripetal pump and the stock solution supply pipe, and detecting the pressure of replacement water flowing back from the connection pipe into the stock solution supply pipe Is provided in the connecting pipe, and the supply stop timing of the replacement water is detected based on the detection value of the pressure sensor.
[0009]
According to a second aspect of the present invention, there is provided the separation plate type centrifugal separator according to the first aspect, wherein the liquid introduction part of the second centripetal pump is located outside the free surface of the light liquid in the separation chamber. It is characterized by having been arranged in.
[0010]
Moreover, the separation plate type centrifuge according to claim 3 of the present invention is characterized in that, in the invention according to claim 1, the liquid outflow portion of the weir is arranged outside the free surface of the light liquid. To do.
[0011]
According to a fourth aspect of the present invention, there is provided a method for operating a separation plate centrifuge, wherein a liquid to be treated is separated from a light liquid having a specific gravity close to each other by using a plurality of separation plates in a separation chamber of the separation plate centrifuge. a step of centrifuging the heavy liquid, to discharge the light liquid separated in the separation chamber and a step of discharging to the outside through the first centripetal pump, to intermittently outside the heavy liquid in the separation chamber from the exhaust outlet A separation plate-type centrifuge comprising: a step, and a step of supplying replacement water into the separation chamber prior to discharging the heavy liquid and replacing a part of the light liquid in the separation chamber with the replacement water In the operation method of the separator, the step of supplying the replacement water from the side of discharging the heavy liquid or the side of supplying the stock solution, and the step of returning the replacement water to the liquid to be treated via a second centripetal pump And the pressure of the replacement water returning to the liquid to be treated is detected via a pressure sensor. And that step, is characterized in that a step of detecting a supply stop timing of the replacement water into the separation chamber based on the detected value of the pressure sensor.
[0012]
According to a fifth aspect of the present invention, there is provided a method for operating the separation plate type centrifugal separator according to the fourth aspect, wherein the replacement water is returned to the liquid to be treated via the second centripetal pump. The pressure is set higher than the pressure of the liquid to be treated.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on the embodiment shown in FIG. FIG. 1 is a block diagram showing an embodiment of the separation plate type centrifuge of the present invention.
[0014]
As shown in FIG. 1, the separation plate centrifuge of this embodiment includes a separation plate centrifuge main body 10 and a controller 50 that controls the separation plate centrifuge main body 10. First, the separation plate type centrifugal separator 10 will be described. As shown in the figure, the separation plate type centrifugal separator 10 includes a cup-shaped rotary drum 12 that rotates at high speed by a drive mechanism (not shown) around a stock solution supply pipe 11 in the vertical direction, and the rotary drum. 12 is a truncated cone-shaped rotating body lid 14 that is fitted to the upper end opening of 12 by a fastening ring 13 to form a rotating body, and slides up and down below the rotating body cover 14 to A main valve 16 that opens and closes the discharge port 15 while being separated from and in contact with the packing 14A, a separation chamber 17 formed by the main valve 16 and the rotating body lid 14, and a predetermined interval vertically between the separation chamber 17 A plurality of stacked truncated conical separation plates 18, and an oil to be treated (for example, containing less than 1% of water) introduced into the separation chamber 17 from the stock solution supply pipe 11 by clarifier operation. Light liquids with specific gravity close to each other through the separation plate 18 (example) Centrifuge to be clean oil exceeds gravity 0.991) L and a heavy liquid (e.g. separated water) H. Further, when the separation water H is accumulated in the rotating body by the separation operation, the separation plate type centrifugal separator 10 supplies the replacement water prior to the discharge of the separation water H as will be described later and supplies the separated clean oil L after separation. After a part of the oil is recovered, the loss of the cleaning oil L is minimized. The discharge ports 15 are formed at equal intervals in the circumferential direction of the rotary drum 12.
[0015]
Thus, a guide cylinder 19 having an enlarged diameter portion opened in a funnel shape is disposed between the separation plate 18 and the raw liquid supply pipe 11, and from the raw liquid supply pipe 11 via the guide cylinder 19. The oil to be treated is introduced into the separation chamber 17. A flat cylindrical body having a central opening is disposed as the first chamber 20 on the upper end surface of the rotating body lid 14, and the cleaning oil L centrifuged in the separation chamber 17 is indicated by an arrow in FIG. Then, it moves inward in the radial direction according to the separation plate 18, and is allowed to flow through the separation chamber 17 through the weir 17 </ b> A and is stored in the first chamber 20. A second chamber 21 that surrounds the first chamber 20 and shares the axial center is disposed on the upper end surface of the rotating body lid 14. In the separation chamber 17, a partition plate 22 is disposed along the inner peripheral surface from the vicinity of the lower end of the rotating body cover 14 to the upper end, and a predetermined gap is formed between the partition plate 22 and the rotating body cover 14. Yes. A plurality of communication holes 23 communicating with the second chamber 21 are formed in the upper end surface of the rotating body lid 14 at equal intervals in the circumferential direction on the upper end surface of the rotating body lid 14, and between the rotating body lid 14 and the partition plate 22. The cleaning oil L guided using the gap as a flow path is guided into the second chamber 21 from the communication hole 23. In other words, since the water content of the oil to be treated is less than 1%, the clean oil L is removed from the separation chamber 17 between the rotating body lid 14 and the partition plate 22 until the separation water H is accumulated in the separation chamber 17 to some extent. And the gap is used as a flow path. In addition, a water supply pipe 21A for supplying replacement water is connected to the second chamber 21, and prior to the discharge of the separation water H, the rotary body, that is, the separation chamber, has a gap between the rotary body lid 14 and the partition plate 22 as a flow path. The replacement water is supplied into 17 and a part of the cleaning oil L is recovered. Further, instead of the water supply pipe 21A, a water supply pipe 21B may be connected to the undiluted liquid supply pipe 11, and replacement water may be supplied from the water supply pipe 21B. In this case, when the replacement water is supplied through the water supply pipe 21B, the replacement water passes through the gap between the guide tube 19 and the main valve 16, reaches the inside of the separation chamber 17 along the shape of the main valve 16, and the white water in FIG. A portion of the clean oil L can be recovered in the same manner as in the case of supplying the replacement water from the water supply pipe 21A by pushing the clean oil L at its hydraulic pressure as indicated by the arrow drawn.
[0016]
Further, a stationary first centripetal pump 24 faces in the first chamber 20, and the light liquid L accumulated in the first chamber 20 is discharged through the first centripetal pump 24, It leads to an external light liquid storage tank (not shown) through the discharge pipe 25. The second chamber 21 is provided with a stationary second centripetal pump 26 so that the cleaning oil L or replacement water flowing into the second chamber 21 is discharged by the second centripetal pump 26. It has become. Further, a weir 26 </ b> A interposed between the first chamber 20 and the second centripetal pump 26 is disposed in the second chamber 21. The weir 26A is formed in a substantially cap shape, and an opening formed in the upper portion of the cap functions as a weir. The free surface of the clean oil L in the separation chamber 17 is defined by a weir 17A when overflowing from the separation chamber 17 to the first chamber 20, and the interface between the clean oil L and the separated water H is the liquid of the second centripetal pump 26. It is defined by the introduction position (outer diameter position) or the liquid outflow position (inner diameter of the opening) of the weir 26A provided between the first chamber 20 and the second centripetal pump 26. When the interface between the clean oil L and the separated water H is defined by the weir 26A, the outer diameter position of the second centripetal pump 26 is set outside the liquid outflow position (the inner diameter of the opening) of the weir 26A. The outer diameter position of the second centripetal pump 26 or the inner diameter position of the weir 26A is set outside the free surface of the cleaning oil L in the separation chamber 17, and the cleaning oil L or the replacement water in the second chamber 21 is the second. The centripetal pump 26 is press-fitted. The second centripetal pump 26 is connected to the undiluted solution supply pipe 11 via a connecting pipe 27 and, as will be described later, clean oil L or replacement water via the second centripetal pump 26 and the connecting pipe 27 under certain conditions. Is returned to the stock solution supply pipe 11.
[0017]
Further, the inner surface of the lower portion 28 of the rotary drum 12 is formed in accordance with the shape of the main valve 16. A gap 29 is formed between the main valve 16 and the lower portion 28 of the rotary drum 12, and valve-operating water is introduced into the gap 29 via a pipe 32 to place the main valve 16 at the lower end of the rotating body lid 14. Press to close the discharge port 15. Further, a sub-valve 31 that slides in the radial direction is disposed in the lower portion 28 of the rotary drum 12, and the sub-valve 31 is slid inward in the radial direction by valve opening operation water introduced from the pipe 30. 31 is opened, the valve-closing working water in the gap 29 is discharged, the main valve 16 is opened, and the separated water H containing sludge accumulated in the rotation is discharged from the discharge port 15 together with the replacement water to clean the rotating body. It becomes. After the separation water L and the replacement water are discharged, the supply of the valve opening operation water is stopped, and the water accumulated in the supply line is extracted from the drain nozzle 33. When the sub valve 31 is closed, the main valve 16 is closed by the supplied valve closing water, and the oil to be treated is processed.
[0018]
Further, as shown in FIG. 1, in the present embodiment, a pressure sensor 34 is attached to the connecting pipe 27, and the pressure sensor 34 is connected to a controller 50. The pressure sensor 34 detects the pressure of the cleaning oil L (replacement water in the replacement process) flowing in the connecting pipe 27 and outputs the detected value to the controller 50. A pressure gauge 34A for displaying the detection value of the pressure sensor 34 is attached to the connecting pipe 27, and the hydraulic pressure of the cleaning oil L or the replacement water can be known through the pressure gauge 34A. Further, a pressure adjusting valve 35 is attached to the connecting pipe 27, and the pressure of the cleaning oil L or the replacement water flowing through the connecting pipe 27 can be appropriately adjusted via the pressure adjusting valve 35. In the present embodiment, the pressure in the connecting pipe 27 is set to, for example, 0.2 MPa or 0.05 MPa by the pressure adjusting valve 35. 0.2 MPa is the pressure of the cleaning oil L during the separation operation, and 0.05 MPa is the pressure of the replacement water when the replacement of the cleaning oil L is completed. These pressures are set in software by a program, and the separation process and the replacement process are automatically repeated. These pressures are set higher than the pressure of the oil to be treated introduced into the stock solution supply pipe 11.
[0019]
Then, the separation of the oil to be treated proceeds, the separated water H is accumulated in the separation chamber 17, the gap between the rotating body lid 14 and the partition plate 22 is filled with the separated water H, and when this gap is sealed, the liquid flow in the gap The value detected by the pressure sensor 34 is reduced from 0.2 MPa to zero. When the pressure sensor 34 detects zero pressure, it outputs this detection signal to the controller 50 so that the controller 50 recognizes that it is time to discharge the separated water H to the outside.
[0020]
Further, when the controller 50 recognizes the discharge timing of the separated water H, it automatically enters a replacement process for recovering an appropriate amount of the clean oil L in order to prevent the loss of the clean oil L staying in the rotating body. That is, the replacement water is supplied from the water supply pipe 21A or the water supply pipe 21B based on the zero pressure detected value of the pressure sensor 34. As a result, the replacement water flows backward in the gap between the rotating body lid 14 and the partition plate 22 or flows into the rotating body, that is, the separation chamber 17 through the stock solution supply pipe 11 and the guide cylinder 19 and is filled. As indicated by the white arrow 1, the clean oil L is pushed toward the separation plate 18, the clean oil L overflows from the weir 17 </ b> A, and the clean oil tank (not shown) passes through the first centripetal pump 24. to recover. When the supply of the replacement water is continued, the outer surface of the second centripetal pump 26 or the free surface of the replacement water (including the separation water H) defined by the weir 26A and the free surface of the clean oil L are in a pressure equilibrium state. Then, a boundary surface between the replacement water and the clean oil L (shown by a one-dotted line in FIG. 1) is formed, and the replacement of the clean oil L with the replacement water is completed. Further, when the replacement water is supplied, the replacement water overflows the inner diameter position of the weir 26 </ b> A and starts to flow to the stock solution supply pipe 11 via the second centripetal pump 26 and the connecting pipe 27. At this time, the pressure in the connecting pipe 27 increases from zero to a set pressure, in this embodiment, 0.05 MPa. The pressure sensor 34 detects this pressure and outputs this detection signal to the controller 50. Based on this detection signal, the controller 50 recognizes the end of the replacement process, and at the same time controls the control valves 30A and 32A attached to the valve closing operation water pipe 30 and the valve opening operation water pipe 32, respectively. The main valve 16 is opened and closed as described above via water. The flow rate of the replacement water when supplying the replacement water into the rotating body can be set as appropriate, but the lowest pressure (0.05 MPa in the present embodiment) at which the set pressure of the pressure sensor 34 that detects the end of the replacement is generated. The flow rate must be higher than the flow rate. Otherwise, the end of the replacement process cannot be detected.
[0021]
Next, the operation method of the separation plate type centrifugal separator of the present invention will be described together with the operation of the separation plate type centrifugal separator 10. When the oil to be treated is supplied to the raw liquid supply pipe 11 of the separation plate centrifuge 10, the oil to be processed passes through the guide cylinder 19 from the raw liquid supply pipe 11 and enters the separation chamber 17 from the lower end of the guide cylinder 19. Inflow. At this time, since the rotating body 12, the rotating body lid 14, and the main valve 16 are rotating at high speed, the oil to be treated is separated into separated water (including sludge) H and clean oil L in the separation chamber 17 by centrifugal force. To do. When the oil to be treated is continuously supplied, the cleaning oil L separated in the separation chamber 17 gradually moves inward in the radial direction along the separation plate 18 and overflows from the separation chamber 17 to the first chamber 20. As a result, the cleaning oil L accumulates in the first chamber 20. Eventually, the cleaning oil L is sent from the first chamber 20 to the light liquid discharge pipe 25 via the first centripetal pump 24 and continuously discharged to a predetermined storage tank.
[0022]
At this time, since the water content of the oil to be treated is less than 1%, the separated water H accumulates only slightly for the supply amount of the oil to be treated. Therefore, a part of the cleaning oil L separated in the separation chamber 17 flows from the lower end of the partition plate 22 to the gap with the rotating body lid 14. The clean oil L flows above the rotating body lid 14 using the gap as a flow path, and reaches the second chamber 21 via the weir 26A. Then, when the inside of the second chamber 21 is filled with the clean oil L, it is discharged into the connecting pipe 27 via the second centripetal pump 26. The cleaning oil L in the connecting pipe 27 is higher in pressure than the oil to be treated flowing through the raw liquid supply pipe 11 by the centrifugal force of the rotating body and the action of the pressure adjusting valve 35 of the connecting pipe 27. At this time, the pressure in the connecting pipe 27 is detected by the pressure sensor 34, and the detected value is output from the pressure sensor 34 to the controller 50, and the pressure of the clean oil L in the connecting pipe 27 is constantly monitored. Since the pressure of the clean oil L in the connecting pipe 27 is higher than that of the oil to be processed in the liquid supply pipe 11 by about 0.2 MPa, for example, the clean oil L merges with the oil to be processed and is again centrifuged together with the oil to be processed.
[0023]
When the above centrifugal separation operation is continued, the separation water H is gradually accumulated in the separation chamber 17 and eventually fills the gap between the partition plate 22 and the rotating body lid 14, and the gap that was the flow path of the clean oil L is removed. Block with separated water H. As a result, the pressure at the interface between the separated water H and the clean oil L is in an equilibrium state, the flow of the liquid (separated water H) in the gap between the partition plate 22 and the rotating body lid 14 is stopped, and the value detected by the pressure sensor 34 is It becomes zero. The controller 50 recognizes the discharge timing of the separated water H in the separation chamber 17 based on the zero detection signal of the pressure sensor 34 at this time, and automatically starts supplying replacement water from the water supply pipe 21A or the water supply pipe 21B. Then, the replacement water flows backward through the gap between the rotating body lid 14 and the partition plate 22, or is mixed with the separated water H in the separation chamber 17 from the raw solution supply pipe 11 through the guide cylinder 19, and is outlined in FIG. As indicated by the arrow, the cleaning oil L increases and gradually pushes the cleaning oil L in the separation chamber 17 to the outside, and a part of the cleaning oil L is recovered. If the replacement water continues to be supplied, the free surface of the replacement water and the free surface of the clean oil L are in a pressure equilibrium state, and the boundary between the replacement water and the clean oil L in the separation chamber 17 (in FIG. Is formed, and becomes a static interface. At this time, the cleaning oil L remaining in the gap between the rotating body lid 14 and the partition plate 22 is replaced with the replacement water and supplied to the stock solution supply pipe 11 through the second centripetal pump 26 and the connecting pipe 27. The oil is separated together with the oil to be treated. Even if the replacement water is continuously supplied, the replacement water does not flow into the separation chamber 17 but flows into the stock solution supply pipe 11 via the second centripetal pump 26 and the connecting pipe 27. Since the flow rate of the replacement water at this time is set to a flow rate larger than the pressure detected by the pressure sensor 34, the pressure sensor 34 detects the pressure when the replacement water flows into the stock solution supply pipe 11 side, and the pressure sensor A detection signal is output from 34 to the controller 50. The controller 50 recognizes the end of the replacement process based on this detection signal, and outputs an opening command for the control valve 32A. As a result, the control valve 32 </ b> A is opened, the valve-opening operation water operates the sub-valve 31 through the pipe 30 to open the main valve 16, and the separated water H is discharged from the discharge port 15. When the separated water H is discharged, the control valve 32A is closed via the controller 50, and the supply of the valve opening operation water is stopped. Next, in response to a command from the controller 50, the control valve 30A is opened and the main valve 16 is closed to prepare for the next separation operation. In these series of operations, since the water content of the oil to be treated is less than 1%, the pressure in the connecting pipe 27 rises to the set value (0.2 MPa) of the pressure regulating valve 35 by the separated water H, and the separated water. The H discharging operation is not hindered.
[0024]
As described above, according to the present embodiment, the oil to be treated is supplied into the separation chamber 17 of the separation plate centrifuge 10, and the separation plate 18 is used to produce the clean oil L and the separation water H having specific gravity close to each other. Centrifugation is performed and the separation water H is discharged to the outside when a predetermined amount of the separation water H is accumulated in the separation chamber 17. Prior to the separation water H being discharged, a part of the cleaning oil L in the rotating body is replaced with replacement water. A replacement step of replacing and recovering with is performed. In this replacement step, the replacement water is supplied from the side from which the separation water H is discharged or the oil to be treated is supplied, and a part of the cleaning oil L in the separation chamber 17 is replaced with the replacement water and recovered. When the cleaning oil L has been recovered, the replacement water returns to the raw liquid supply pipe 11 side via the second centripetal pump, but when the replacement water returns to the treated oil side, the pressure of the replacement water is increased. Since the controller 50 is detected based on the detection value of the pressure sensor and the supply stop timing of the replacement water, that is, the end of the replacement process can be detected based on the detection value of the pressure sensor, a constant amount of replacement water is always supplied. It can be reliably and stably supplied into the rotating body without excess or deficiency, and the supply amount of the replacement water does not fluctuate due to pressure fluctuation on the replacement water side. In addition, since part of the replacement water does not overflow from the rotating body, it is not necessary to dispose of the separated water H containing sludge, and it is also necessary to set a replacement water supply time as in the prior art. Therefore, the supply amount of replacement water does not fluctuate due to an artificial setting error.
[0025]
In addition, although the said embodiment demonstrated the case where fuel oil was used as to-be-processed oil, this invention is not limited to to-be-processed oil, It is with respect to the various to-be-processed liquids which consist of a liquid with a specific gravity difference. The present invention can be applied.
[0026]
【The invention's effect】
According to the invention described in claims 1 to 5 of the present invention, the overflow of the replacement water from the rotating body is eliminated, and the water supply time is reduced without being affected by the pressure fluctuation on the supply side of the replacement water. It is possible to provide a separation plate type centrifugal separator that can supply a certain amount of replacement water into a rotating body reliably and stably without excess or deficiency, and a method for operating the same.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of a separation plate centrifuge of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Separator plate type centrifuge 11 Stock solution feed pipe 12 Rotating drum 14 Rotating body lid 15 Discharge port 16 Main valve 17 Separation chamber 21A Water feed pipe 21B Water feed pipe 18 Separation plate 24 First centripetal pump 26 Second centripetal pump 26A Weir 27 Connecting pipe 34 Pressure sensor 34A Pressure gauge 35 Pressure regulating valve

Claims (5)

A rotating drum having an upper end opened, a rotating body lid fitted into the upper end opening of the rotating drum to form a rotating body, a partition plate arranged with a gap with respect to the rotating body cover, and the rotating drum A main valve that moves up and down in a state of being inserted into the rotor and opens and closes a discharge port formed in a side portion of the rotating body, and a predetermined interval vertically in a separation chamber formed between the main valve and the partition plate. A plurality of separation plates stacked with a gap between them, and centrifuge the liquid to be treated supplied from the raw solution supply pipe into the separation chamber into light and heavy liquids having a specific gravity close to each other through the separation plate, While the light liquid in the separation chamber is discharged to the outside through the first centripetal pump, the replacement water is supplied into the separation chamber before the heavy liquid in the separation chamber is intermittently discharged from the discharge port. Separation plate type centrifugal separation in which a part of the light liquid in the separation chamber is replaced with the replacement water and recovered A pipe for supplying the replacement water into the rotating body through a gap between the rotating body lid and the partition plate or via the stock solution supply pipe, and between the rotating body cover and the partition plate. A second centripetal pump that discharges the replacement water flowing through the gap, or a second centripetal pump, and a dam having a diameter smaller than the outer diameter of the second centripetal pump at the lower stage, and the second centripetal pump And a connecting pipe that communicates with the undiluted solution supply pipe and a pressure sensor that detects the pressure of the replacement water flowing back from the connecting pipe into the undiluted solution supply pipe is provided in the connecting pipe, and based on the detected value of the pressure sensor. And a separation plate type centrifugal separator characterized by detecting the supply stop timing of the replacement water. The separation plate type centrifugal separator according to claim 1, wherein the liquid introduction part of the second centripetal pump is disposed outside the free surface of the light liquid in the separation chamber. 2. The separation plate type centrifugal separator according to claim 1, wherein a liquid outflow portion of the weir is disposed outside a free surface of the light liquid. A step of centrifuging the liquid to be processed into a light liquid and a heavy liquid having a specific gravity close to each other using a plurality of separation plates in the separation chamber of the separation plate centrifuge, and a first centripetal operation of the light liquid separated in the separation chamber. a step of discharging to the outside through the pump, and a step of discharging the intermittently outside the heavy liquid in the separation chamber from the exhaust outlet, the substituted water prior to discharging the heavy liquid is supplied to the separation chamber In a method for operating a separation plate centrifuge comprising a step of substituting and recovering a part of the light liquid in the separation chamber with the replacement water, the side from which the heavy liquid is discharged or the raw liquid is supplied A step of supplying replacement water, a step of returning the replacement water to the liquid to be treated via a second centripetal pump, and a pressure of the replacement water returning to the liquid to be processed are detected via a pressure sensor. Based on the process and the detected value of the pressure sensor. The method of operating the separating plate type centrifugal separator, characterized in that a step of detecting a supply stop timing of replacement water. The operation of the separation plate type centrifugal separator according to claim 4, wherein the pressure of the replacement water returning to the liquid to be treated via the second centripetal pump is set higher than the pressure of the liquid to be treated. Method.

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