JP2004154694A - Solid-liquid separating method using centrifugal separator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-liquid separating method using a centrifugal separator by which the liquid to be treated can be separated into a liquid and a solid without hindrance, and from which the separated liquid and solid can be discharged easily and then the separated solid can be sorted even when the liquid to be treated contains voluminus solid and the solid apt to stick or to break. <P>SOLUTION: The centrifugal separator is constituted so that the solid-mixed liquid to be treated is supplied to the inside of a rotating body and separated into the liquid and the solid by the centrifugal force and at least the separated liquid is discharged continuously. A fixed amount of a viscous substance which is hardly dissolved in the liquid to be treated and has fluidity is supplied to the inside of the rotating body as a solid capturing agent all at once or continuously. The liquid to be treated is supplied continuously and separated into the liquid and the solid by the centrifugal force. Only the separated liquid or all of the separated liquid and the separated solid are discharged continuously, and the supply of the liquid to be treated is stopped and the contents in the rotating body is discharged after the prescribed time passes. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a solid-liquid separation method using a centrifugal separator that supplies a liquid to be treated mixed with solids into a rotating body that rotates at a high speed, performs solid-liquid separation by centrifugal force, and continuously discharges at least the separated liquid. It is.
[0002]
[Prior art]
Conventionally, lubricating oils and fuel oils containing solids and water, etc. are separated and removed to remove the solids and water etc. to recover clean oil, or solids are collected from various liquids containing useful solids. 2. Description of the Related Art A centrifuge that separates solids with a specific gravity difference due to a high centrifugal force of a rotating body that rotates at a high speed is used for solid-liquid separation and the like that are separated and collected.
[0003]
Also, among the centrifugal separators, a separation plate group in which a separation plate group in which a number of separation plates are stacked in a rotating body is mounted, and fine particles and the like can be efficiently separated by utilizing a large settling area of the separation plate group. 2. Description of the Related Art Centrifuges are used in many industrial fields, and are generally used in large numbers for cleaning lubricating oil and fuel oil, particularly in ships.
[0004]
A conventional centrifugal separator will be described with reference to FIG. 2 using a separator plate type centrifuge as an example. The separator plate type centrifugal separator has a rotating drum 11 having a sludge discharge hole 13 on an outer peripheral portion and an upper portion of the rotating drum 11. The rotating body 10 mainly composed of the rotating body lid portion 12 to be covered is fixed to the rotating shaft 22, and a large number of separation plates 14 formed of frustoconical thin plates are laminated in the rotating body 10 in the axial direction of the rotating body. A valve cylinder 16 for opening and closing the formed separation plate group 15 and the sludge discharge hole 13 is mounted.
[0005]
In the separation operation by the centrifugal separator, the undiluted solution is supplied from the undiluted solution inlet 28 of the undiluted solution supply pipe 17 inserted and mounted at the axial position of the rotating body 10, and the supplied undiluted solution descends through the guide cylinder 20. The centrifugal force caused by the high speed rotation of the rotating body 10 introduced into the separation chamber of the rotating body 10 and rotated via the rotating shaft 22 separates the light liquid having a low specific gravity from the heavy liquid or the solid having a high specific gravity with a specific gravity difference. .
[0006]
The separated heavy liquid and solid matter are accumulated in the largest diameter portion in the rotating body 10, and the light liquid flows upward through the gap between the separation plate group 15 and the light liquid discharge impeller provided in the light liquid discharge passage. It is pumped out by 18 and discharged out of the rotating body 10 from the light liquid outlet 26. In the separation and discharge of the light liquid, the remaining heavy liquid and solids are further settled and separated while the light liquid flows upward through the gap between the separation plate groups 15, so that the clarification is efficiently performed. Will be promoted.
[0007]
When a certain amount of heavy liquid and solid liquid accumulated in the maximum diameter portion of the rotating body 10 accumulate, a heavy liquid flow path formed by the heavy liquid guide plate 21 and the inner wall of the rotating body lid 12 is formed. Then, it is pumped out by the heavy liquid impeller 19 and discharged out of the rotating body 10 from the heavy liquid outlet 27.
[0008]
The discharge of the light liquid and the heavy liquid is controlled by adjusting the liquid accumulation position by an adjusting plate 25 provided in the rotating body 10.
[0009]
Further, by supplying water at a predetermined time interval from the water supply device 24, the operation and stop of the pilot valve 23 are controlled, whereby the valve cylinder 16 provided therein is slid up and down to reach the maximum diameter portion. By controlling the opening and closing of the provided sludge discharge hole 13, the discharge of sludge composed of solid matter and a part of heavy liquid accumulated in the maximum diameter portion of the rotating body 10 is controlled. (For example, refer to Patent Document 1).
[0010]
Further, the separator-type centrifuge has a structure for discharging heavy liquid without a heavy liquid discharge impeller or an adjusting plate, a structure for continuously discharging sludge from a nozzle type sludge discharge hole, or a valve cylinder type sludge. An apparatus using both discharge and nozzle-type sludge discharge is generally known (for example, see Patent Document 2).
[0011]
In addition, the present invention is not applied only to the separation plate type centrifugal separator, but supplies a liquid to be treated mixed with solids into a rotating body, performs solid-liquid separation by centrifugal force, and at least separates the separated liquid. As long as it is a centrifugal separator that continuously discharges, a non-porous basket type centrifugal separator or the like can be applied.
[0012]
[Patent Document 1]
Japanese Patent Publication No. 57-034023 [Patent Document 2]
JP 2001-239184 A
[Problems to be solved by the invention]
In the solid-liquid separation method in the conventional centrifugal separator, light liquid, heavy liquid and solids are efficiently separated, and a light liquid having high clarity can be easily obtained, but when the amount of sludge increases, In the valve opening / closing type sludge discharge structure, since the number of times of opening and closing of the valve cylinder for discharging the sludge increases, the valve cylinder, the valve packing, and the like become severely worn, and there is a problem that costs and operating time loss due to replacement of parts increase. . Further, in the nozzle-type sludge discharge structure, there is a possibility that a discharge failure may occur due to accumulation of sludge in the nozzle portion. In particular, in the case of a liquid to be treated containing a solid which is easily fixed, there is a problem that the solid is fixed to the inner wall of the rotating body, making it impossible to discharge the solid. Classification by pod specific gravity is not possible.
[0014]
The present invention has been made in view of the above problems, and a liquid to be treated containing a large amount of solid matter, a liquid to be treated containing a solid matter that easily adheres, or a liquid to be treated containing a solid matter that is easily broken. Even if there is any problem, the object is to provide a solid-liquid separation method using a centrifugal separator, which can be separated and easily discharged without any trouble, and can also classify solids.
[0015]
[Means for Solving the Problems]
The gist of the present invention for achieving the above object is that, in the invention according to claim 1, a liquid to be treated mixed with a solid is supplied to a rotating body and solid-liquid separated by centrifugal force. In a centrifuge that continuously discharges, after supplying a fixed amount of a viscous substance that is difficult to dissolve in the liquid to be treated and has fluidity as a solid substance capturing agent into the rotating body, the liquid to be treated is continuously supplied. A method for separating solid and liquid by a centrifugal separator, wherein solid-liquid separation is performed by centrifugal force, the separated liquid is continuously discharged, and after a predetermined time, the supply of the liquid to be treated is stopped and the contents of the rotating body are discharged. It is.
[0016]
With the above configuration, the solid substance is hardly dissolved in the liquid to be treated and the viscous substance having fluidity is captured and retained in the solid substance capturing agent, and thereafter discharged, whereby the solid substance is rotated. There is no danger of sticking to the inner wall of the tank and causing a problem that discharge becomes impossible.Therefore, a liquid to be treated that contains a large amount of solids, a liquid to be treated that contains solids that easily adhere, or a solid that is easily broken The liquid to be treated can be separated and easily discharged without any trouble. In addition, by appropriately adjusting the viscosity and specific gravity of the solid trapping agent according to the solid, the classification operation can be performed based on the difference in sedimentation speed of the solid in the solid trapping agent.
[0017]
Further, in the invention according to claim 2, in a centrifugal separator that supplies a liquid to be treated mixed with solids into a rotating body, performs solid-liquid separation by centrifugal force, and continuously discharges at least the separated liquid, While continuously supplying a viscous substance that is difficult to dissolve in the liquid to be treated and has fluidity to the rotating body as a solid substance trapping agent, the liquid to be treated is continuously supplied and solid-liquid separated by centrifugal force. A solid-liquid separation method using a centrifugal separator, characterized by continuously discharging a solid substance capturing agent.
[0018]
According to the above configuration, the solid is hardly dissolved in the liquid to be treated and the viscous substance having fluidity is captured in the solid capturing agent, held and continuously discharged, whereby the solid is rotated. Since there is no danger of sticking to the inner wall of the body and causing a problem that discharge becomes impossible, a liquid to be treated containing a large amount of solid matter, a liquid to be treated containing a solid matter which easily adheres, or a solid matter which is easily broken is used. Even the mixed liquid to be treated can be separated and easily discharged without any trouble. In addition, by appropriately adjusting the viscosity and specific gravity of the solid trapping agent according to the solid, the classification operation can be performed based on the difference in sedimentation speed of the solid in the solid trapping agent.
[0019]
According to a third aspect of the present invention, in the solid-liquid separation method using the centrifugal separator according to the first or second aspect, the centrifugal separator is formed of a frustoconical thin plate in a rotating body. Is a solid-liquid separation method using a centrifugal separator, which is a separating plate type centrifugal separator that is internally provided by laminating a large number in the axial direction.
[0020]
According to the configuration, in addition to the effect of the first aspect, while the light liquid flows upward in the gap between the separation plates, the remaining heavy liquid and solids are further settled and separated, and clarification is efficiently promoted. Therefore, the light liquid, the heavy liquid, and the solid matter are efficiently separated, and a light liquid having high clarity can be easily obtained.
[0021]
According to a fourth aspect of the present invention, in the solid-liquid separation method using the centrifuge according to the first, second, or third aspect, the liquid to be treated is an oil mixed with a solid, This is a solid-liquid separation method using a centrifuge in which the substance trapping agent is a viscous substance prepared by dissolving a polymer flocculant in water to adjust the concentration to a predetermined concentration, and the separated liquid is clear oil.
[0022]
With the above configuration, the effects described in claim 1, claim 2, or claim 3 can be maximized.
[0023]
In the above, as the solid substance capturing agent, yam separation extract, gelatin, a biologically produced viscous substance, alginate, agar, natural polymer substances such as gelatin, polyvinyl alcohol, polyacrylic acid, synthetic polymer substances such as polyacrylamide, In addition, various coagulants used in water treatment such as anionic polymer coagulant, cationic polymer coagulant or nonionic polymer coagulant can be used. The concentration is appropriately adjusted according to the type of the solid substance in the liquid to be treated, and the liquid substance is used as a viscous substance such as a gel substance, a sol substance, or a high viscosity substance.
[0024]
When the viscosity of the solid substance capturing agent is adjusted, it is preferable to use a viscous substance having a viscosity of 10,000 to 200,000 cps, preferably 25,000 to 150,000 cps, and a specific gravity of 1.0 to 1 cps. However, the present invention is not limited thereto, as long as it is a viscous substance that is hardly dissolved in the liquid to be treated and has fluidity.
[0025]
The liquid to be treated mixed with the solid matter to be treated in the present separation method includes oils and fats such as fuel oil, waste mineral oil and used edible oil containing 0.1 to 2.0 wt% of inorganic solid matter, plankton. It can be applied to water containing microorganisms such as oils and fats or water which need to be classified by containing solids having a plurality of specific gravity differences.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram of a solid-liquid separator showing an enlarged sectional view of a rotating body of a centrifuge according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a rotating body of a conventional centrifuge. is there. In FIG. 1, the same reference numerals as in FIG.
[0027]
In FIG. 1, reference numeral 1 denotes a rotating body 10 mainly composed of a rotating body 11 having a sludge discharge hole 13 in an outer peripheral portion and a rotating body lid 12 for covering the upper part of the rotating body 11 in a casing (not shown). 22 and a valve cylinder for opening and closing a separation plate group 15 and a sludge discharge hole 13 formed by laminating a large number of separation plates 14 formed of frustoconical thin plates in the rotating body 10 in the axial direction of the rotating body. 16 is a separation plate type centrifugal separator to which No. 16 is attached.
[0028]
Further, in the separation plate type centrifugal separator 1, a stock solution supply pipe 17 is inserted and mounted at an axial position of the rotating body 10, and a guide tube 20 for introducing the supplied stock solution into the separation chamber of the rotating body 10 is provided with a stock solution. A light liquid discharge impeller 18 provided concentrically with the supply pipe 17 and provided in a light liquid discharge passage for discharging the light liquid flowing upward through the gap between the separation plate groups 15, The heavy liquid provided in the heavy liquid discharge flow path passes through the heavy liquid flow path formed by the heavy liquid guide plate 21 for discharging the accumulated heavy liquid and the heavy liquid from the solid matter and the inner wall of the rotating body lid 12. An impeller 19 and an adjusting plate 25 for adjusting discharge of the light liquid and the heavy liquid are provided therein.
[0029]
Further, a hydraulic water supply device 24 and a pilot valve 23 are provided for sliding the valve cylinder 16 provided therein up and down to control opening and closing of the sludge discharge hole 13 provided in the maximum diameter portion.
[0030]
Reference numeral 2 denotes a stock solution tank for storing a liquid to be treated mixed with solids (hereinafter referred to as a stock solution), and reference numeral 3 denotes a fining solution for storing a clarified processing solution in which solids are separated by the centrifuge 1. The liquid tank No. 4 is a solid substance trapping agent tank that stores at least one solid substance trapping agent of a gel-like substance, a sol-like substance, or a high-viscosity substance that is hardly dissolved in the liquid to be treated and has fluidity. is there.
[0031]
Reference numeral 5 denotes a stock solution supply pump that supplies a stock solution from the stock solution tank 2 to the centrifuge 1, and reference numeral 6 denotes a solid material that supplies a solid material capturing agent from the solid material capturing agent tank 4 to the centrifuge 1. It is a capture agent supply pump.
[0032]
By the solid-liquid separator, for example, a method of treating a high-viscosity substance adjusted to a predetermined viscosity or specific gravity by dissolving a polymer coagulant with water as a solid solution, using a fat or oil mixed with a solid as a stock solution, The details will be described below.
[0033]
After the centrifuge 1 is operated, the polymer flocculant is dissolved in water in the solid substance trapping agent tank 4 to adjust the concentration to a predetermined specific gravity, and the adjusted gel-like fluid (hereinafter referred to as a trapping substance) is solidified. When the material capturing agent supply pump 6 supplies the raw material into the rotary body 10 from the raw material inlet 28 of the raw solution supply pipe 17 inserted and mounted at the axial position of the rotary body 10 through the solid material capturing agent supply path b, the captured substance Is stored in the maximum diameter portion of the rotating body 10, and then is pumped out by the heavy liquid impeller 19 through the heavy liquid flow path formed by the heavy liquid guide plate 21 and the inner wall of the rotating body lid 12, and the solid matter is It is circulated from the trapping agent circulation path d to the solid substance trapping agent tank 4.
[0034]
While continuing the circulation of the fluid, the stock solution is supplied from the stock solution tank 2 from the stock solution inlet 28 of the stock solution supply pipe 17 inserted and mounted at the axial position of the rotating body 10 through the stock solution supply path a by the stock solution supply pump. Then, the supplied undiluted solution is introduced into the separation chamber of the rotator 10 by descending the guide cylinder 20 and centrifugal force generated by the high speed rotation of the rotator 10 rotated via the rotation shaft causes the fat and oil (hereinafter, referred to as light grease) to have a low specific gravity. A light liquid) and a solid having a high specific gravity and a mixture of water and a solid (hereinafter referred to as a heavy liquid) are separated by a specific gravity difference.
[0035]
The separated heavy liquid and solid matter are accumulated in the largest diameter portion in the rotating body 10, and the light liquid flows upward through the gap between the separation plate group 15 and the light liquid discharge impeller provided in the light liquid discharge passage. It is pumped out by 18 and discharged out of the rotating body 10 from the light liquid outlet 26 and stored in the clarifying liquid tank 3 through the light liquid discharge channel c.
[0036]
In the separation and discharge of the light liquid, the remaining heavy liquid and solids are further settled and separated while the light liquid flows upward through the gap of the separation plate group 15, so that the clarification is efficiently performed. Will be promoted.
[0037]
When a certain amount of heavy liquid and solid liquid accumulated in the maximum diameter portion of the rotating body 10 accumulate, a heavy liquid flow path formed by the heavy liquid guide plate 21 and the inner wall of the rotating body lid 12 is formed. Then, it is pumped out by the heavy liquid impeller 19 and discharged out of the rotating body 10 from the heavy liquid outlet 27.
[0038]
The discharge of the light liquid and the heavy liquid is controlled by adjusting the accumulation position of the heavy liquid by the adjusting plate 25 provided in the rotating body 10.
[0039]
Further, by supplying water at a predetermined time interval from the water supply device 24, the operation and stop of the pilot valve 23 are controlled, whereby the valve cylinder 16 provided therein is slid up and down to reach the maximum diameter portion. By controlling the opening and closing of the sludge discharge hole 13 provided, the discharge of the sludge composed of the solid matter accumulated in the maximum diameter portion of the rotating body 10 and a part of the heavy liquid is controlled, but most of the solid matter flows. Since the sludge discharge hole 13 is captured and discharged by the animal, there is almost no need to open and close the sludge discharge hole 13, or at least the frequency of opening and closing the sludge discharge hole 13 is reduced as compared with the conventional method.
[0040]
In addition, by appropriately adjusting the viscosity and specific gravity of the solid trapping agent according to the solid, the classification operation can be performed based on the difference in the sedimentation speed of the solid in the solid trapping agent.
[0041]
【Example】
Next, an example in which turbine oil whose solid matter concentration is adjusted by the method of the present invention will be described.
Turbine oil No. 32 Kanto Loam No. 11 was adjusted to a solid concentration of 0.3 kg / m 3 to obtain a stock solution. A high-viscosity substance prepared by dissolving an anionic polymer flocculant with water and adjusting the concentration to 2 wt% was used as a solid substance capturing agent.
The test method was such that the rotating body of the separation plate type centrifuge was rotated at a centrifugal force of 11,150 G, and the solid matter trapping agent was connected to the undiluted liquid supply pipe at 2 L / Hr by a solid matter trapping agent supply pump. It was supplied into the rotating body via the capture agent supply pipe, and was discharged and circulated through the heavy liquid discharge pipe. The liquid to be treated was supplied at 100 L / Hr from a stock solution supply pipe.
[0042]
According to the above test, Kanto loam which is extremely easy to adhere to the rotating body wall is dispersed and captured in the solid matter capturing agent, discharged without being fixed to the rotating body wall surface, and to obtain clear turbine oil as light liquid. And continuous operation for a long time was possible.
[0043]
After completion of the test, the solid matter trapping agent, the turbine oil and the liquid mixed with Kanto loam in the rotating body were all collected and separated by a batch centrifugal sedimentation tube at a centrifugal force of 1,000 G. And the Kanto loam were separated into solid capture agents mixed and dispersed, and there was no sedimentation of the Kanto loam. As a result, it was found that the solid was trapped by the solid trap and was stably dispersed. It has also been found that there is no problem in circulating and using the solid matter trapping agent for a long time.
[0044]
【The invention's effect】
The present invention can separate and easily discharge a liquid to be treated containing a large amount of solids, a liquid to be treated which contains solids which are easily fixed, or a liquid which contains solids which are easily broken. And a solid-liquid separation method using a centrifugal separator that can further classify solids.
[Brief description of the drawings]
FIG. 1 is a system diagram of a solid-liquid separator showing an enlarged sectional view of a rotating body of a centrifuge according to an embodiment of the present invention. FIG. 2 is an enlarged sectional view of a rotating body of a conventional centrifuge. [Explanation of symbols]
1: separation plate type centrifugal separator 2: stock solution tank 3: clarification solution tank 4: solid matter trapping agent tank 5: stock solution supply pump 6: solid matter trapping agent supply pump 10: rotating body

Claims (4)

In a centrifugal separator that supplies a liquid to be treated mixed with solids into a rotating body and separates it into solid and liquid by centrifugal force, and continuously discharges at least the separated liquid, it is difficult to dissolve in the liquid to be treated and has fluidity. After a certain amount of the viscous substance is supplied as a solid trapping agent into the rotating body, the liquid to be treated is continuously supplied, and solid-liquid separation is performed by centrifugal force, and the separated liquid is continuously discharged. A solid-liquid separation method using a centrifuge, wherein the supply of the liquid is stopped and the contents of the rotating body are discharged. In a centrifugal separator that supplies a liquid to be treated mixed with solids into a rotating body and separates it into solid and liquid by centrifugal force, and continuously discharges at least the separated liquid, it is difficult to dissolve in the liquid to be treated and has fluidity. While continuously supplying the viscous substance as a solid trapping agent into the rotating body, the liquid to be treated is continuously supplied and solid-liquid separated by centrifugal force, and the separated liquid and the solid trapping agent are continuously discharged. A solid-liquid separation method using a centrifuge. The centrifugal separator according to claim 1 or 2, wherein the centrifugal separator is a separator-type centrifugal separator in which a plurality of frustro-conical thin plates are stacked in a rotating body in an axial direction and internally provided. Solid-liquid separation method using a machine. The liquid to be treated is an oil mixed with solids, the solids trapping agent is a viscous substance prepared by dissolving a polymer coagulant with water to a predetermined concentration, and the separated liquid is a clear oil. A solid-liquid separation method using the centrifugal separator according to claim 1, 2 or 3.

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