JP4397516B2 - 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, stably and reliably discharge a heavy liquid separated by a so-called clarifier operation that separates a heavy liquid and a light liquid having specific gravity close to each other. The present invention relates to a separation plate type centrifuge that can be detected in a short time and an operation 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, in order to intermittently discharge the separated water that has been separated and filled in the rotating body to the outside, generally, a moisture detector is used to detect the dielectric constant of the moisture in the clean oil, and based on the change in the dielectric constant. The valve is opened and the separated water is discharged to prevent moisture from entering the clean oil.
[0005]
[Problems to be solved by the invention]
However, in the case of a conventional separator-type centrifuge, the moisture in the cleaning oil is monitored as a moisture detector by monitoring the change in the dielectric constant, and the dielectric constant corresponding to the preset moisture value (trigger value) Since the main valve is operated to discharge a heavy liquid such as separated water when equal or exceeding, there are various problems as follows.
(1) In general, in the case of mineral oil (for example, marine fuel oil or lubricating oil), the amount of water contained in the oil to be treated is usually less than 1%. The rate of change was extremely small even when detected, and the rate of change could not be detected without a highly sensitive moisture detector. Increasing the detection sensitivity of the moisture detector will naturally increase the cost of the moisture detector.
(2) In addition, since the rate of change of the dielectric constant varies depending on the type of oil to be treated, a moisture detector with circuit characteristics suitable for each oil to be treated is prepared, or the dielectric constant of the moisture detector is individually set. It is necessary to rework, and the handling is complicated. In addition, since minute dielectric constant changes must be detected with high accuracy, hardware limitations to maintain the resolution of the moisture detector, circuits such as product switching or temperature correction, etc. are required, and the circuit configuration is complicated. Tended to be.
(3) Furthermore, since the moisture detector for detecting the dielectric constant is vulnerable to disturbances such as bubbles in the clean oil and the measurement temperature, a defoaming countermeasure (for example, about 0.2 MPa) is used to eliminate the influence of such disturbances. In addition to the cost of the moisture detector, a further increase in cost was incurred. In addition, the amount of oil to be treated varies constantly, or the amount of separated solids, separated water, and the like varies, so there is a problem in the effectiveness of disturbance countermeasures.
(4) Since the amount of water contained in the oil to be treated is as low as less than 1%, it takes a long time to accumulate as separated water. There is also a risk of being invited.
(5) Further, it can be said that a moisture detector using a dielectric constant is expensive in itself, and there is a problem that the dielectric constant must be set according to the oil to be treated as described above.
[0006]
The present invention has been made to solve the above problems, and can reliably detect the discharge timing of the heavy liquid without depending on disturbance such as bubbles, the type of liquid to be processed, or the processing amount. It is an object of the present invention to provide a separator-type centrifuge that can be manufactured at a lower cost than when a dielectric constant is used as a moisture detector, and an operation method thereof.
[0007]
[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 centrifuged to the outside through the first centripetal pump, and the heavy liquid in the separation chamber is intermittently discharged from the discharge port. In the separation plate type centrifugal separator that discharges to the outside, the clearance between the rotating body lid and the partition plate flows. A second centripetal pump that discharges the processing liquid to be discharged, communicates the second centripetal pump and the stock solution supply pipe via the connection pipe, and returns to the stock solution supply pipe from the connection pipe A pressure sensor for detecting a part of the pressure is provided in the connecting pipe, and the discharge timing of the heavy liquid accumulated in the separation chamber is detected based on the detection value of the pressure sensor.
[0008]
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.
[0009]
According to a third aspect of the present invention, there is provided a method for operating a separation plate type centrifuge, wherein a liquid to be treated is separated from a light liquid having a specific gravity close to each other using a plurality of separation plates in a separation chamber of the separation plate type centrifuge. Centrifugation into heavy liquid, the light liquid separated in the separation chamber is discharged to the outside via the first centripetal pump, and the heavy liquid separated and accumulated in the separation chamber is intermittently discharged to the outside. In the operation method of the separation plate type centrifuge, a step of returning a part of the light liquid separated in the separation chamber to the liquid to be processed through a second centripetal pump, and a light liquid returning to the liquid to be processed The method includes a step of detecting the pressure of the liquid through a pressure sensor, and a step of detecting a discharge timing of the heavy liquid in the separation chamber based on a detection value of the pressure sensor.
[0010]
According to a fourth aspect of the present invention, there is provided a method for operating the separation plate type centrifugal separator according to the third aspect, wherein the pressure of the light liquid returns to the liquid to be treated via the second centripetal pump. Is set higher than the pressure of the liquid to be treated.
[0011]
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.
[0012]
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 cleaned oil exceeds gravity 0.991) L and a heavy liquid (e.g. separated water) H. The discharge ports 15 are formed at equal intervals in the circumferential direction of the rotary drum 12.
[0013]
Between the separation plate 18 and the raw liquid supply pipe 11, a guide cylinder 19 having a diameter-enlarged portion opened in a funnel is disposed, and the oil to be treated from the raw liquid supply pipe 11 passes through the guide cylinder 19. 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, overflows from the separation chamber 17, and accumulates 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.
[0014]
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 flowing into the second chamber 21 is discharged by the second centripetal pump 26. Yes. 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). The outer diameter position of the second centripetal pump 26 is set outside the free surface of the clean oil L in the separation chamber 17 so that the clean oil L in the second chamber 21 is press-fitted into the second centripetal pump 26. It has become. The second centripetal pump 26 is connected to the raw liquid supply pipe 11 via a connecting pipe 27, and the cleaning oil L is returned to the raw liquid supply pipe 11 via the second centripetal pump 26 and the connecting pipe 27. .
[0015]
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 the valve-operating water is introduced into the gap 29 via the pipe 30 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 32. 31 is opened, the valve closing operation water in the gap 29 is discharged, the main valve 16 is opened, and the separation water L in the separation chamber 17 is discharged from the discharge port 15. After the separation water L is 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.
[0016]
Thus, as shown in FIG. 1, in this embodiment, a pressure sensor 34 is attached to the connecting pipe 27, and the pressure sensor 34 is connected to the controller 50. The pressure of the clean oil L flowing in the connecting pipe 27 is detected by the pressure sensor 34, and this detected value is output to the controller 50. The controller 50 controls the control valves 30A and 32A respectively attached to the valve-closing working water pipe 30 and the valve-opening working water pipe 32 based on the detection value of the pressure sensor 34, and the above-described control water is supplied via the respective working water. The main valve 16 is opened and closed as follows. In addition, 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 clean oil L 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 flowing through the connecting pipe 27 can be adjusted as appropriate via the pressure adjusting valve 35. In the present embodiment, the pressure in the connecting pipe 27 is set to 0.2 MPa, for example, by the pressure adjusting valve 35. This pressure is set higher than the pressure of the oil to be treated introduced into the stock solution supply pipe 11. Then, the separation process of the oil to be treated proceeds, the separation 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 separation water H, and the gap is sealed. The flow disappears and the value detected by the pressure sensor 34 becomes zero. When the pressure sensor 34 detects zero pressure, it outputs this detection signal to the controller 50, operates the control valves 30A and 32A via the controller 50, opens and closes the main valve 16, and discharges the separated water H to the outside. It is.
[0017]
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.
[0018]
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 into the gap between the lower end of the partition plate 22 and the rotating body lid 14. The cleaning oil L flows above the rotating body lid 14 using the gap as a flow path, and reaches the second chamber 21. Then, when the inside of the second chamber 21 is filled with the clean oil L, the inside of the connecting pipe 27 is discharged through 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. The clean oil L in the connecting pipe 27 has a pressure higher than that of the oil to be processed in the liquid supply pipe 11 by, for example, about 0.2 MPa.
[0019]
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 outputs an opening command for the control valve 32A. As a result, the control valve 32A is opened, and the valve-opening operation water operates the sub valve 31 via the pipe 32 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.
[0020]
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 supply the clean oil L and the separation water H having specific gravity close to each other. When the separation water H is discharged to the outside after the centrifugal separation and the separation water H is accumulated in the separation chamber 17 in a predetermined amount, the oil to be treated is centrifuged into the clean oil L and the separation water H in the separation chamber 17. Thereafter, a part of the cleaning oil L separated in the separation chamber 17 is returned to the treated oil side via the connecting pipe 27. At this time, the pressure of the clean oil L in the connecting pipe 27 is detected by the pressure sensor 34, and the controller 50 determines the separation water H in the separation chamber 17 based on a signal when the detected value of the pressure sensor 34 becomes zero. Since the discharge timing can be recognized, the discharge timing of the separated water H can be easily and reliably known only by using the pressure sensor 34, and the separated water H can be discharged quickly and reliably. In addition, since the pressure sensor 34 is used as a detector, a detector can be obtained at a lower cost than a conventional moisture detector that detects a dielectric constant, and the oil to be treated can be obtained as in a conventional moisture detector. Various adjustments are not required depending on the type, and handling is simple, and there is no influence of disturbances such as bubbles in the clean oil and measurement temperature. Can do.
[0021]
In the above embodiment, the case where fuel oil is used as the oil to be treated has been described. However, the present invention is not limited to the oil to be treated, and the present invention can be applied to various liquids to be treated. it can.
[0022]
【The invention's effect】
According to the first to fourth aspects of the present invention, it is possible to reliably detect the discharge timing of the heavy liquid without depending on the disturbance such as bubbles, the type of the liquid to be processed or the processing amount. In addition, it is possible to provide a separation plate type centrifugal separator that can be manufactured at a lower cost than a case where the dielectric constant is used as a moisture detector and an operation method thereof.
[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 18 Separation plate 24 First centripetal pump 26 Second centripetal pump 27 Connecting pipe 34 Pressure sensor 34A Pressure gauge 35 Pressure adjustment valve

Claims (4)

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 disposed 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, In the separation plate type centrifugal separator that discharges the light liquid in the separation chamber to the outside through the first centripetal pump and intermittently discharges the heavy liquid in the separation chamber to the outside from the discharge port. And providing a second centripetal pump that discharges the processing liquid flowing through the gap between the partition plates The second centripetal pump and the stock solution supply pipe are connected via a connection pipe, and a pressure sensor for detecting the pressure of a part of the light liquid flowing back from the connection pipe into the stock solution supply pipe is connected to the second centripetal pump. A separation plate type centrifugal separator, which is provided in a pipe and detects the discharge timing of heavy liquid accumulated in the separation chamber based on a detection value of the pressure sensor. 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. The liquid to be treated is centrifuged 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 the light solution separated in the separation chamber is supplied to the first centripetal pump. In the operation method of the separation plate type centrifuge, in which the heavy liquid separated and accumulated in the separation chamber is intermittently discharged to the outside, one of the light liquids separated in the separation chamber is discharged. Based on the detected value of the pressure sensor, the step of returning the liquid portion to the treated liquid side via the second centripetal pump, the step of detecting the pressure of the light liquid returning to the treated liquid side via the pressure sensor And a step of detecting the discharge timing of the heavy liquid in the separation chamber. 4. The method for operating a separation plate centrifuge according to claim 3, wherein the pressure of the light liquid that returns to the liquid to be treated via the second centripetal pump is set higher than the pressure of the liquid to be treated. .

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