JP2014147882A - Method for concentrating phenol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for concentrating phenol, capable of recovering high-concentration phenol efficiently and easily from a phenol-containing mixture.SOLUTION: The method of the present invention comprises: a gasification step of gasifying a mixture of phenol and water by placing the mixture to an atmosphere having a pressure of 130 Pa or above and 4000 Pa or below and a temperature of 20°C or above and 120°C or below; and a phenol recovery step of recovering phenol deposits by placing the gasified mixture to an atmosphere having a pressure of 130 Pa or above and 4000 Pa or below and a temperature of 0°C or above and 30°C or below. Furthermore, the method of the present invention comprises: a gasification step of placing a mixture of phenol and water to an atmosphere having temperature and pressure sufficient to yield a gasified state of phenol and water; and a phenol recovery step of recovering phenol deposits from the gasified mixture by changing at least either of the temperature and the pressure.

Description

  The present invention relates to a phenol concentration method.

  Phenolic resins are used in many industrial fields such as automobile breakers and electronic parts. However, if a very small amount of phenols is contained in water, chlorophenols are produced during chlorination. In order to produce a strange odor, drainage standards are established. Therefore, it is necessary to separate a very small amount of phenol contained in the waste water.

  Thus, a method using a separation membrane is used as a method for separating a very small amount of phenol contained in water such as waste water. In particular, a method using a pervaporation membrane is used because of its excellent phenol selectivity (see Patent Document 1). Thereby, phenol can be separated from the mixture containing phenol.

  However, the method using a separation membrane has a problem that high-purity phenol cannot be recovered from a mixture containing phenol in a high yield.

Japanese Patent Laid-Open No. 5-57151

  It is an object of the present invention to provide a phenol concentration method capable of efficiently and easily recovering a high concentration of phenol from a phenol-containing mixture.

Such an object is achieved by the present invention described in the following (1) to (9).
(1) A vaporization step of placing the mixture of phenol and water in a gas state by placing the mixture in a pressure of 130 Pa to 4000 Pa and a temperature of 20 ° C. to 120 ° C.
A phenol concentration method comprising: placing the mixture in the gaseous state in an atmosphere of a pressure of 130 Pa to 4000 Pa and a temperature of 0 ° C. to 30 ° C. to recover a phenol precipitate.

(2) a vaporization step of placing a mixture of phenol and water under an atmosphere of temperature and pressure at which the phenol and the water become gaseous;
And a phenol recovery step of changing at least one of the temperature and the pressure, thereby recovering a phenol precipitate.

  (3) The said vaporization process is a phenol concentration method as described in said (1) or (2) which is the process of making the said mixture of a liquid state into the said gaseous state by the osmosis | permeation vaporization method.

  (4) The phenol concentration method according to any one of (1) to (3), further including a heating step of heating the mixture before the vaporization step.

  (5) The phenol concentration method according to (4), wherein the heating temperature in the heating step is 20 ° C. or higher and 95 ° C. or lower.

  (6) The phenol concentration method according to any one of (1) to (5), further including a water recovery step of recovering a water precipitate after the phenol recovery step.

  (7) The phenol concentration method according to any one of (1) to (6), further including a pretreatment step of treating the phenol-containing mixture using a reverse osmosis membrane before the vaporization step.

  (8) The phenol concentration method according to any one of (1) to (7), wherein the mixture includes an inorganic ionic substance.

  (9) The phenol concentration method according to any one of (1) to (8), wherein the mixture exhibits alkalinity.

  According to the present invention, a high concentration of phenol can be efficiently and easily recovered from a phenol-containing mixture.

It is a figure which shows an example of the phenol concentration apparatus for performing the phenol concentration method of this invention. It is the figure which expanded the pervaporation membrane module among phenol concentration apparatuses. It is process drawing which shows suitable embodiment of the phenol concentration method of this invention.

Hereinafter, it demonstrates in detail based on suitable embodiment of the phenol concentration method of this invention.
The phenol concentration method of the present invention is a method for concentrating phenol in a mixture containing phenol and water. According to the phenol concentration method of the present invention, a high concentration of phenol can be efficiently and easily recovered from a mixture. In particular, even in a mixture having a low phenol concentration, the concentration of phenol in the mixture can be increased by using the phenol concentration method of the present invention. Moreover, since the obtained phenol deposit has high purity of phenol, it can be used as a raw material for various industrial products.

≪Phenol concentration device≫
First, prior to describing the phenol concentration method of the present embodiment, a phenol concentration apparatus used for the phenol concentration method of the present embodiment will be described.

  FIG. 1 is a view showing an example of a phenol concentration apparatus for performing the phenol concentration method of the present invention, and FIG. 2 is an enlarged view of a pervaporation membrane module in the phenol concentration apparatus.

  The phenol concentrator 100 shown in FIG. 1 has a mixture tank 110, a pervaporation membrane module 120, a phenol precipitate recovery unit 130, an impermeate storage tank 140, and a water precipitate recovery unit 170.

  Among these, the mixture tank 110 and the pervaporation membrane module 120 are connected by a supply pipe 115. A pretreatment module 150 and a heating unit 160 are provided in the middle of the supply pipeline 115. Examples of the pretreatment module 150 include a module that performs sedimentation treatment using a flocculant, filtration treatment, reverse osmosis membrane treatment, azeotropic treatment, distillation treatment, and the like. Moreover, as the heating unit 160, one provided with heating means such as a heater can be cited.

  On the other hand, the permeation side (secondary side) of the pervaporation membrane module 120 and the phenol precipitate recovery unit 130 are connected by a permeation conduit 125. Furthermore, the phenol precipitate recovery unit 130 and the water precipitate recovery unit 170 are connected by a permeation conduit 135. Further, the supply side (primary side) of the pervaporation membrane module 120 and the impermeable substance storage tank 140 are connected by a discharge conduit 126.

  Further, as shown in FIG. 2, the pervaporation membrane module 120 includes a housing 121 and a pervaporation membrane 1 provided so as to separate the internal space of the housing 121. Of the internal space of the housing 121, the primary side of the pervaporation membrane 1 is the supply side space 122, and the secondary side of the permeation vaporization membrane 1 is the permeation side space 123.

  The mixture 10 processed by the phenol concentrator 100 is a mixture of phenol and water.

  Here, the mixture of phenol and water means a mixture containing at least phenol and water, and may contain other components other than water and phenol. For example, the mixture 10 may include an inorganic ionic substance having an inorganic ion such as sodium ion, sulfate ion, phosphate ion, potassium ion, or ammonium ion, or a salt thereof.

  Moreover, the density | concentration of the phenol in the mixture 10 is not specifically limited, For example, they are 0.1 mass% or more and 20 mass% or less. In particular, even with a dilute mixture 10 having a phenol concentration of 10% by mass or less, a high concentration of phenol can be efficiently and easily recovered by using the phenol concentration method of the present embodiment.

  Moreover, although the phenol concentration method can be used for a mixture having any ion index (pH), it can be preferably used particularly for a material exhibiting alkalinity. Specifically, it can be applied to a mixture having a hydrogen ion index (pH) of 7.5 or more and 9.5 or less.

≪Phenol concentration method≫
Below, suitable embodiment of the phenol concentration method performed using the phenol concentration apparatus 100 shown in FIG. 1, FIG. 2 is described.

FIG. 3 is a process diagram showing a preferred embodiment of the phenol concentration method of the present invention.
As shown in FIG. 3, the phenol concentration method of this embodiment includes [1] pretreatment step S1, [2] heating step S2, [3] vaporization step S3, [4] phenol recovery step S4, [5] A water recovery step S5.

  In the phenol concentration method described below, [3] As the vaporization step S3, the permeation vaporization method will be described as a representative case.

  In the phenol concentration method described below, [1] water is mainly removed from the mixture 10 to obtain the mixture 20, [2] the mixture 20 is heated, and [3] phenol and water in the mixture 25 are mixed. After obtaining the vaporized mixture 30 by placing the mixture 25 in an atmosphere at a temperature and pressure at which the gas phase becomes a gaseous state, [4] recovering the phenol precipitate 40 from the vaporized mixture 30; Furthermore, [5] a method of recovering the water precipitate 50 from the treatment residue 41 remaining by recovering the phenol precipitate 40 from the mixture 30 will be mainly described.

Hereinafter, each step will be described in detail.
[1] Pretreatment step S1
First, a mixture 10 containing phenol and water is prepared.

  In the present embodiment, a case where the following is used as the mixture 10 will be mainly described.

  The mixture 10 is assumed to be composed of phenol and water. The mixture 10 is in a liquid state at room temperature.

  Next, the mixture 10 is pretreated. In the pretreatment, foreign matters in the mixture 10 are removed or the volume of the mixture 10 is reduced.

  As shown in FIG. 1, when the mixture 10 stored in the mixture tank 110 is sent to the pretreatment module 150 via the supply line 115, the pretreatment is performed there.

  As described above, the pretreatment module 150 includes, for example, sedimentation treatment using a flocculant, filtration treatment, reverse osmosis membrane treatment, azeotropic treatment, distillation treatment, and the like. Can be used in combination. Among these, it is particularly preferable to use reverse osmosis membrane treatment. Thereby, the volume of the mixture 10 can be reduced efficiently.

  Here, the reverse osmosis membrane treatment refers to a treatment that removes water contained in the mixture 10 and reduces the volume of the mixture 10 using a reverse osmosis membrane (RO membrane). Specifically, for example, by supplying the mixture 10 to the supply side (primary side) across the reverse osmosis membrane and applying pressure to the supply side, the water in the mixture 10 permeates the reverse osmosis membrane from the supply side. And move to the transmission side. By using such a reverse osmosis membrane treatment, water can be mainly removed from the mixture 10, and a mixture 20 having a smaller amount of water than the mixture 10 can be obtained. That is, the volume of the mixture 10 can be reduced. Further, the reverse osmosis membrane is a membrane having a property that water permeates but phenol hardly permeates. Therefore, by subjecting the mixture 10 to the reverse osmosis membrane treatment, the phenol concentration of the mixture 20 subjected to the reverse osmosis membrane treatment can be made higher than that of the mixture 10 before the reverse osmosis membrane treatment.

  Further, the shape of the reverse osmosis membrane is not particularly limited, and for example, any membrane such as a flat membrane, a hollow fiber membrane, a spiral membrane, and a tuber membrane may be used.

  In addition, the material of the reverse osmosis membrane is not particularly limited, and examples thereof include cellulose acetate, aromatic polyamide, polyvinyl alcohol, polysulfone, and the like, and one or more of these can be used in combination.

  Moreover, what kind of pretreatment is used as the pretreatment module 150 can be appropriately selected according to the substance contained in the mixture 10. For example, when the mixture 10 contains other components other than water and phenol, a filtration process using a separation membrane or the like that selectively separates the other components can be used.

  In addition, what is necessary is just to change suitably the time which performs a pretreatment with the quantity, the kind, etc. of the mixture 10 to be used, For example, it is 5 minutes or more and 24 hours or less.

  Moreover, you may abbreviate | omit this pretreatment process S1 suitably according to the kind, quantity, etc. of a mixture. For example, when the phenol concentration in the mixture is relatively high, this pretreatment step S1 may be omitted.

[2] Heating step S2
Next, the liquid mixture 20 is heated to obtain a mixture 25.

  As shown in FIG. 1, the mixture 20 subjected to the pretreatment is sent to the heating unit 160 through the supply pipe 115 and heated by the heating unit 160. Thereby, the mixture 25 is obtained. By providing such a heating step S2, the processing efficiency of the mixture 20 can be further increased in the vaporization step S3 using a permeation vaporization film described later. This will be described in detail in [3] Vaporization step S3.

  Further, the heating unit 160 is not particularly limited, and examples thereof include those provided with heating means such as a heater.

  Moreover, although the temperature (heating temperature) which heats the mixture 20 is not specifically limited, 20 to 95 degreeC is preferable, 30 to 70 degreeC is more preferable, 40 to 60 degreeC is further more preferable. Thereby, in the vaporization process S3 by the later-described [3] pervaporation method, the pervaporation film 1 can be prevented from being deteriorated, and the processing efficiency of the mixture 20 can be further increased.

  In addition, what is necessary is just to change suitably the time which pre-processes with the quantity, the kind, etc. of the mixture 20 to be used, For example, it is 5 minutes or more and 24 hours or less.

  Moreover, you may abbreviate | omit this heating process S2 suitably according to the kind, quantity, etc. of a mixture. For example, in the vaporization step S3 described later, when the pervaporation method is not used, the main heating step S2 may be omitted.

[3] Vaporization step S3
Next, the liquid mixture 25 is processed by the pervaporation method. Thereby, the gaseous mixture 30 can be obtained from the liquid mixture 25.

  Here, this embodiment is characterized by having a vaporization step S3 in which a mixture of phenol and water is placed in an atmosphere of temperature and pressure at which the phenol and water become gaseous before the phenol recovery step S4. .

  Specifically, in this embodiment, before the phenol recovery step S4, the mixture of phenol and water is placed in a gas state by placing the mixture in a pressure of 130 Pa to 4000 Pa and a temperature of 20 ° C. to 120 ° C. It has a vaporization step S3. In particular, in the vaporization step S3, it is more preferable to place the mixture 25 in an atmosphere at a pressure of 150 Pa to 3500 Pa, a temperature of 30 ° C. to 110 ° C., and an atmosphere of a pressure of 180 Pa to 3000 Pa and a temperature of 40 ° C. to 100 ° C. More preferably,

  By placing the mixture 25 in an atmosphere having a pressure and temperature within the above ranges, the gaseous mixture 30 can be easily and reliably obtained from the mixture 25 only by controlling the temperature and pressure. Thus, prior to the phenol recovery step S4 for recovering the phenol precipitate 40, which will be described in detail later, in the vaporization step S3, the mixture 25 is surely brought into a gaseous state, whereby the phenol precipitate 40 finally obtained is obtained. The phenol concentration can be made particularly high.

  On the other hand, when the pressure is less than the lower limit value, a large amount of energy may be consumed to reduce the pressure, and the stability of the phenol concentrator 100 may not be sufficiently maintained. Moreover, when a pressure exceeds the said upper limit, it may be difficult to make the mixture 25 into a vaporization state. As a result, there is a possibility that the phenol precipitate 40 cannot be recovered in [4] phenol recovery step S4.

  On the other hand, when the temperature is lower than the lower limit, it is difficult to make the mixture 25 in a gas state, and the processing efficiency may be reduced. Moreover, when temperature exceeds the said upper limit, there exists a possibility that a great amount of energy may be consumed for heating. Moreover, when the gaseous mixture 30 is obtained from the liquid mixture 25 using the pervaporation method, the pervaporation membrane 1 may be deteriorated and durability may be reduced.

  In the present embodiment, in the main vaporization step S3, as described above, the liquid state mixture 25 is placed in the atmosphere of the pressure and temperature by using the osmotic vaporization method. A gaseous mixture 30 can be obtained.

  Here, the pervaporation method refers to a method of obtaining the gaseous mixture 30 by using the pervaporation membrane 1 and allowing the permeation vaporization membrane 1 to permeate. Specifically, as shown in FIGS. 1 and 2, the mixture 25 is sent to the supply side space 122 of the pervaporation membrane module 120 through the supply pipe 115. And the permeation | transmission side space 123 of the pervaporation membrane module 120 is made into the pressure within the said range with the decompression pump (not shown) connected to the permeation | transmission pipe | tube path 125. FIG. At this time, the temperature of the supply-side space 122 and the transmission-side space 123 is maintained at a temperature within the above range. Thereby, the mixture 25 passes through the pervaporation membrane 1 from the supply side space 122 and moves to the permeation side space 123. As a result, the gaseous mixture 30 can be obtained in the transmission side space 123. Thus, the gaseous mixture 30 can be more easily and reliably obtained from the mixture 25 by placing it in the atmosphere of the temperature and pressure using the pervaporation method.

  The pervaporation membrane 1 has a function of preferentially permeating phenol over water. Therefore, the phenol in the mixture 25 passes through the pervaporation membrane 1 from the supply side space 122 and moves to the permeation side space 123 with priority over water. As a result, the mixture 30 obtained in the transmission side space 123 has a higher phenol concentration than the mixture 25. Thus, by using the pervaporation method, the mixture 30 in the vaporized state can be obtained from the mixture 25, and the phenol concentration in the obtained mixture 30 can be made higher than that of the mixture 25.

  Furthermore, in [2] heating step S2, by heating the mixture 20 to the temperature described in [2] heating step S2, the treatment efficiency of the mixture 25 in the main vaporization step S3 using the pervaporation method is increased. Can be increased.

  The shape of the pervaporation membrane 1 is not particularly limited. For example, a dense membrane such as a bag shape, a flat membrane shape, a hollow fiber shape, a tubular shape, or a spiral shape can be employed.

  The average thickness of the pervaporation membrane 1 is not particularly limited, but is preferably about 10 to 500 μm, and more preferably about 20 to 400 μm. By setting the average thickness of the pervaporation membrane 1 within the above range, the supply-side space 122 and the permeation-side space 123 can be reliably separated, and the vaporized mixture 30 can be more reliably obtained from the mixture 25. Can do.

  The material of the pervaporation membrane is not particularly limited, and examples thereof include polymer membranes such as polyimide, polyamide, polysulfone, polyethersulfone, and polyamideimide, or composite membranes thereof. Among these, those containing polyamide are particularly preferable. Thereby, the mechanical characteristics of the pervaporation membrane 1 can be enhanced while enhancing the phenol separation performance.

  In addition, although the shaping | molding method of the pervaporation film | membrane 1 is not specifically limited, For example, a dry film forming method, a wet film forming method, an extrusion method etc. are mentioned. Among these, the extrusion method is particularly preferable. When the pervaporation membrane is formed by the extrusion method, for example, the permeation vaporization membrane 1 is obtained by extruding a material containing the material constituting the pervaporation membrane in the range of a melting temperature of 100 ° C. or more and 300 ° C. or less. be able to.

  Further, the pervaporation film 1 is coated with an electron beam irradiation treatment, a corona discharge treatment, an arc discharge treatment, an excimer light irradiation treatment, a plasma treatment, an etching treatment, or a functional group having a high affinity with phenol as required. You may give a process etc. Among these, those subjected to electron beam irradiation treatment are particularly preferable. Thereby, mechanical characteristics, such as the durability of the pervaporation membrane 1, can be improved without greatly impairing the permeability of phenol.

  Moreover, the content rate of the phenol in the mixture 30 obtained using the pervaporation method is 2 mass% or more and 95 mass% or less, for example. By using the pervaporation method as described above, even when a lean mixture 25 having a phenol concentration of 0.1% by mass or more and 10% by mass or less is used, the phenol content is within the above range. The content can be increased up to.

  When the mixture 25 contains an inorganic ionic substance, the inorganic ionic substance is stored in the vaporization step S3 from the supply side space 122 of the pervaporation membrane module 120 through the discharge pipe 126 and stored as an impermeable substance. Since it is sent to the tank 140 and separated from the phenol, the purity of the recovered phenol can be increased.

[4] Phenol recovery step S4
Next, in the vaporization step S3, the gaseous mixture 30 is placed in an atmosphere having a predetermined temperature and pressure. Thereby, the phenol deposit 40 mainly containing phenol can be obtained.

  In the present embodiment, after the vaporization step S3, phenol that recovers phenol precipitates from the gaseous mixture obtained in the vaporization step S3 by changing at least one of the temperature and pressure in the vaporization step S3. And a recovery step S4.

  Specifically, in the present embodiment, the gaseous recovery mixture obtained in the vaporization step S3 is placed in an atmosphere having a pressure of 130 Pa to 4000 Pa and a temperature of 0 ° C. to 30 ° C. to recover a phenol precipitate. And S4. In particular, in the phenol recovery step S4, it is more preferable to place the mixture 30 in an atmosphere of a pressure of 150 Pa to 3500 Pa, a temperature of 5 ° C. to 27 ° C., and a pressure of 180 Pa to 3000 Pa, a temperature of 10 ° C. to 25 ° C. More preferably, it is placed below.

  [3] By placing the mixture 30 in a gaseous state through the vaporization step S3 in an atmosphere having a pressure and temperature within the above range, water remains in a gaseous state, and only phenol is converted from a gaseous state to a solid state or The state can be changed to a liquid state. Thus, phenol and water can be phase-separated by making the state of phenol and the state of water different from each other. Thus, in this phenol recovery process S4, water and phenol can be reliably and easily separated by changing at least one of the temperature and pressure in the vaporization process S3. As a result, it is possible to obtain a liquid or solid phenol precipitate 40 mainly containing phenol and a gas-state treatment residue 41 mainly containing water. In addition, this process residue 41 is provided to [5] water collection | recovery process S5 mentioned later.

  On the other hand, when the pressure is less than the lower limit value, a large amount of energy may be consumed to reduce the pressure, and the stability of the phenol concentrator 100 may not be sufficiently maintained. Moreover, when a pressure exceeds the said upper limit, there exists a possibility that the water which should be kept in a gaseous state originally may be in a liquid state or a solid state. Therefore, both water and phenol in the mixture 30 are in a liquid state or a solid state, and there is a possibility that the mixture 30 cannot be separated into water and phenol. As a result, not only the phenol but also a relatively large amount of water is mixed in the obtained phenol precipitate 40, and there is a possibility that the phenol concentration of the phenol precipitate 40 cannot be increased.

  On the other hand, when the temperature is lower than the lower limit value, water that should be kept in a gaseous state may be in a liquid state or a solid state, and both water and phenol in the mixture 30 are phase-separated. There is a risk that it will not be possible. As a result, not only the phenol but also a relatively large amount of water is mixed in the obtained phenol precipitate 40, and there is a possibility that the phenol concentration of the phenol precipitate 40 cannot be increased. Moreover, when temperature exceeds the said upper limit, the phenol which should be made into a liquid state or a solid state will remain in a gaseous state, and the phenol deposit 40 may not be obtained.

  Thus, the present embodiment is characterized in that the vaporization step S3 as described above is provided prior to the phenol recovery step S4. Furthermore, [1] Pretreatment step S1 is provided before vaporization step S3 and [4] phenol recovery step S4, so that foreign matters in mixture 10 can be removed in advance or volume of mixture 10 can be reduced. Therefore, water and phenol can be separated more efficiently. Therefore, the processing time of the phenol concentration process can be shortened. [1] In the pretreatment step S1, by performing pretreatment using a reverse osmosis membrane, water in the mixture 10 can be removed preferentially, so that the effect of reducing the volume of the mixture 10 is further increased. Prominently demonstrated.

  Moreover, in this phenol collection | recovery process S4, although what is necessary is just to change at least one of the temperature and pressure in vaporization process S3, it is more preferable to change temperature especially. Thereby, since control of each process can be performed easily rather than changing a pressure for every process, a series of phenol concentration processes can be performed more simply. Therefore, the recovery efficiency of the phenol deposit 40 can be improved.

  Moreover, when changing temperature in this phenol collection | recovery process S4, it is preferable to change so that the temperature in this phenol collection | recovery process S4 may become lower than the temperature in vaporization process S3. Moreover, when changing a pressure in this phenol collection process S4, it is preferable to change so that the pressure in this phenol collection process S4 may become lower than the pressure in vaporization process S3. Thereby, in this phenol collection | recovery process S4, the state of phenol and the state of water can be made into a different state more reliably.

  Such a phenol recovery step S4 can be performed using the apparatus shown in FIG. Specifically, as shown in FIG. 1, the mixture 30 is sent from the permeation side space 123 of the pervaporation membrane module 120 to the phenol precipitate recovery unit 130 via the permeation conduit 125. Then, in the phenol precipitate recovery unit 130, the mixture 30 is placed in an atmosphere of a predetermined temperature and pressure. Thereby, the phenol deposit 40 mainly containing phenol can be obtained.

  The phenol precipitate recovery unit 130 may be any unit that adjusts the pressure and temperature to a temperature and pressure within the above-described range, and examples thereof include various temperature adjusting means, a vacuum pump, and the like. .

  Moreover, the content rate of the phenol in the obtained phenol deposit 40 is 85 mass% or more, for example. In particular, even when a lean mixture having a phenol concentration of 0.1% by mass or more and 10% by mass or less is used, if the phenol concentration method of the present embodiment is used, the phenol content is within the above range. The content can be increased up to. In this way, a high concentration of phenol can be recovered.

  Since the phenol precipitate 40 after concentration obtained by the present phenol recovery step S4 has a high phenol concentration as described above, it can be widely used as an industrial raw material. When the phenol precipitate 40 is used as an industrial raw material, for example, a necessary amount of water may be added to the phenol precipitate 40. As described above, the phenol precipitate 40 can be used as a wide range of industrial raw materials because a high-concentration phenol aqueous solution can be easily obtained if diluted with an amount of water suitable for the intended use. Moreover, since the phenol and water in the mixture 10 can be reliably and easily separated by using the phenol concentration method of the present embodiment, the efficiency of phenol disposal and detoxification treatment can be increased.

[5] Water recovery step S5
Next, the treatment residue 41, which is water in a gaseous state from which the phenol precipitate 40 is separated from the mixture 30 through the [4] phenol recovery step S4, is cooled under a predetermined pressure. Thereby, the water precipitate 50 mainly containing water can be obtained.

  Specifically, as shown in FIG. 1, the treatment residue 41 is sent from the phenol precipitate recovery unit 130 to the water precipitate recovery unit 170 through the permeation conduit 135. In the water precipitate recovery unit 170, the treatment residue 41 is placed in an atmosphere having a predetermined temperature and pressure. Thereby, the water precipitate 50 containing mainly water in solid state or liquid state can be obtained.

  Specifically, the treatment residue 41 is preferably placed in an atmosphere of a pressure of 130 Pa to 4000 Pa and a temperature of −200 ° C. to 10 ° C., and an atmosphere of a pressure of 150 Pa to 3500 Pa and a temperature of −150 ° C. to 0 ° C. More preferably, it is placed in an atmosphere of a pressure of 180 Pa to 3000 Pa and a temperature of −100 ° C. to −5 ° C. Thereby, it is possible to easily and reliably obtain the water precipitate 50 mainly containing water in a solid state or a liquid state. Thus, by making the water precipitate 50 into a solid state or a liquid state, it becomes easier to collect water compared to the case where the water precipitate 50 is in a gas state.

  The water precipitate recovery unit 170 may be any unit that adjusts the pressure and temperature to a temperature and pressure within the above range, such as those equipped with various coolers, liquid nitrogen, glycol antifreeze, etc. And those equipped with a vacuum pump or the like.

  [3] The vaporization step S3, [4] the phenol recovery step S4, and [5] the water recovery step S5 may be set to the temperatures and pressures described in the respective steps. It is preferable to change only the temperature of each step while keeping it constant, which makes it easier to control each step than changing the temperature and pressure for each step, and a series of phenol concentration steps. It can be performed more efficiently and more easily. As a result, the recovery efficiency of the phenol precipitate 40 and the water precipitate 50 can be improved. In addition, since it is not necessary to provide a vacuum pump or the like for controlling the pressure for each process, the apparatus can be simplified.

  The total treatment time of [3] vaporization step S3, [4] phenol recovery step S4 and [5] water recovery step S5 is not particularly limited, but is preferably 30 minutes or more and 72 hours or less, preferably 1 hour or more. Particularly preferred is 48 hours or less. Thereby, phenol concentration can be performed efficiently and the collection | recovery efficiency of the phenol precipitate 40 and the water precipitate 50 can be improved.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above.

  For example, in the above-described embodiment, the vaporization step has been described using the osmotic vaporization method, but the vaporization step is not limited to this, for example, a vacuum distillation treatment in which a mixture is vaporized using a vacuum distillation apparatus, or a steam A treatment that vaporizes by heating the mixture, such as a permeation treatment, may be used.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

1. Phenol concentration of the mixture (Example 1)
[1] Pretreatment step First, water, phenol, and an inorganic ionic substance were mixed to prepare a mixture (pH 8.5) of phenol concentration: 2% by mass and inorganic ionic substance: 1% by mass.

  Moreover, a reverse osmosis membrane was prepared, the mixture was arrange | positioned at the supply side of a reverse osmosis membrane, and the reverse osmosis membrane process was performed at 25 degreeC.

[2] Heating step Next, the mixture was heated at 60 ° C.

[3] Vaporization Step Next, a polyamide-containing polymer (polyamide content of 35 to 40%) is used as the pervaporation film, and a film shape (flat surface) having a thickness of 100 μm is obtained by extrusion at a melting temperature of 180 to 230 ° C. A film formed into a shape was prepared.

  Next, the pervaporation membrane was attached to the pervaporation membrane module, and the heat-treated mixture was supplied to the supply side of the pervaporation membrane. Next, the permeation side of the pervaporation membrane module was decompressed to 1330 Pa by a decompression pump. And both the supply side and the permeation | transmission side were hold | maintained in 60 degreeC atmosphere, and the pervaporation was given.

[4] Phenol recovery step Next, the vaporized mixture was placed in an atmosphere at 22 ° C while maintaining 1330 Pa. Thereby, a phenol precipitate was obtained.

[5] Water Recovery Step Next, the processing residue obtained by removing the phenol precipitate from the mixture was placed in a glass trap cooled with a −20 ° C. glycol-based antifreeze liquid at 1330 Pa. Thereby, a water precipitate was obtained.

(Examples 2 and 3)
[2] Phenol was concentrated in the same manner as in Example 1 except that the conditions of the heating step, [3] vaporization step, and [4] phenol recovery step were changed as shown in Table 1.

(Example 4)
[1] Phenol was concentrated in the same manner as in Example 1 except that the pretreatment step was omitted.

(Examples 5 to 17)
[2] Phenol was prepared in the same manner as in Example 4 except that the conditions of the heating step, [3] vaporization step, [4] phenol recovery step and [5] water recovery step were as shown in Table 1, respectively. Concentrated.

(Example 18)
[2] The heating step was omitted, and the phenol was concentrated in the same manner as in Example 4 except that the pressure in the [4] phenol recovery step was changed.

(Example 19)
[2] Vapor permeation treatment in which the heating step is changed, and [3] The vapor permeation method is not performed in the vaporization step, but instead the vapor permeation method is used to treat the mixture at the temperature and pressure shown in Table 1. Except that, phenol was concentrated in the same manner as in Example 4.

(Example 20)
Phenol was concentrated in the same manner as in Example 4 except that a mixture (pH 8.0) having a phenol concentration of 7% by mass and an inorganic ionic substance of 1% by mass was used as the mixture for phenol concentration.

(Comparative Example 1)
[4] Phenol was concentrated in the same manner as in Example 1 except that the temperature of the phenol recovery step was changed to -20 ° C.

(Comparative Example 2)
[4] Phenol was concentrated in the same manner as in Example 4 except that the temperature of the phenol recovery step was changed to -20 ° C.

(Comparative Example 3)
[4] Phenol was concentrated in the same manner as in Example 4 except that the temperature of the phenol recovery step was changed to -10 ° C.

(Comparative Example 4)
[4] Phenol was concentrated in the same manner as in Example 4 except that the temperature in the phenol recovery step was changed to 55 ° C.

(Comparative Example 5)
[3] Phenol was concentrated in the same manner as in Example 4 except that the pressure in the vaporization step, [4] phenol recovery step, and [5] water recovery step was changed to 5320 Pa.

(Comparative Example 6)
[3] Phenol was concentrated in the same manner as in Example 4 except that the pressure in the vaporization step, [4] phenol recovery step, and [5] water recovery step was changed to 93 Pa.

(Comparative Example 7)
[3] Phenol was concentrated in the same manner as in Example 4 except that the temperature of the vaporization step was changed to 150 ° C.

(Comparative Example 8)
[3] Phenol was concentrated in the same manner as in Example 4 except that the temperature of the vaporization step was changed to 5 ° C.

(Comparative Example 9)
[4] Phenol was concentrated in the same manner as in Example 4 except that the pressure in the phenol recovery step was changed to 5187 Pa.

(Comparative Example 10)
[4] Phenol was concentrated in the same manner as in Example 4 except that the pressure in the phenol recovery step was changed to 80 Pa.

(Comparative Example 11)
[3] Phenol was concentrated in the same manner as in Example 4 except that the pressure in the vaporization step was changed to 5187 Pa.

(Comparative Example 12)
[3] The phenol was concentrated in the same manner as in Example 4 except that the pressure in the vaporization step and [4] the phenol recovery step were changed to 80 Pa and the total time of the three steps was changed.

  Tables 1 and 2 collectively show the configurations of phenol aqueous solutions and the phenol concentration conditions in the above Examples and Comparative Examples.

  In the table, reverse osmosis membrane treatment is “reverse osmosis”, treatment by osmosis vaporization method is “permeation vaporization”, treatment using vapor permeation method is “vapor transmission”, vaporization process, phenol recovery process and water recovery process. The total time required was shown as “total time for 3 steps”.

  Moreover, about the mixture used for phenol concentration, it described in the column of the pre-processing process for the convenience of description of a table | surface.

  Moreover, the phenol concentration of the mixture before performing the phenol concentration of the mixture was measured using Shimadzu Corporation make and capillary gas chromatograph system GC-2014.

  Moreover, the phenol deposit obtained by each Example and Comparative Examples 1-3, 9 was a liquid state, a solid state, or the state in which these were mixed.

2. Evaluation of phenol precipitate The phenol concentration of the phenol precipitate obtained as described above was measured. The measurement results are shown in Tables 1 and 2.

  In addition, the phenol concentration of the obtained phenol deposit was measured using Shimadzu Corporation capillary gas chromatograph system GC-2014.

3. Evaluation of total permeation flux The total permeation flux was calculated for the phenol precipitate and water precipitate obtained as described above. The measurement results and calculation results are shown in Tables 1 and 2.

The total permeation flux was obtained from the following relational expression.
Total permeation flux = Permeation / Effective area of pervaporation membrane

  As is clear from Tables 1 and 2, it was recognized that high concentration of phenol can be efficiently concentrated by using the phenol concentration method of the present invention. Moreover, even with a dilute mixture of phenol and water, it was possible to increase the concentration ratio of phenol.

  On the other hand, in the phenol concentration method of each comparative example, it was recognized that the phenol concentration rate was low. Moreover, in Comparative Examples 4-8 and 10-12, a phenol deposit could not be obtained.

DESCRIPTION OF SYMBOLS 1 ... Pervaporation membrane 100 ... Phenol concentrator 110 ... Mixture tank 115 ... Supply pipe line 120 ... Permeate vaporization membrane module 121 ... Case 122 ... Supply side space 123 ... Permeation side space 125 ... Permeation pipe 126 ... Discharge pipe 130 ... Phenol deposit recovery unit 135 ... Permeation conduit 140 ... Imperme reservoir tank 150 ... Pretreatment module 160 ... Heating unit 170 ... Water precipitate recovery unit 10, 20, 25, 30 ... Mixture 40 ... Phenol precipitate 41 ... Treatment residue 50 ... water precipitate S1 ... pretreatment step S2 ... heating step S3 ... vaporization step S4 ... phenol recovery step S5 ... water recovery step

Claims (9)

A vaporizing step of placing the mixture of phenol and water in a gas state by placing the mixture in a pressure of 130 Pa to 4000 Pa and a temperature of 20 ° C. to 120 ° C .;
A phenol concentration method comprising: placing the mixture in the gaseous state in an atmosphere of a pressure of 130 Pa to 4000 Pa and a temperature of 0 ° C. to 30 ° C. to recover a phenol precipitate. A vaporization step of placing a mixture of phenol and water under an atmosphere of temperature and pressure at which the phenol and water become gaseous;
And a phenol recovery step of changing at least one of the temperature and the pressure, thereby recovering a phenol precipitate.   The phenol concentration method according to claim 1, wherein the vaporizing step is a step of bringing the mixture in a liquid state into the gaseous state by an osmotic vaporization method.   The phenol concentration method according to any one of claims 1 to 3, further comprising a heating step of heating the mixture before the vaporizing step.   The phenol concentration method according to claim 4, wherein the heating temperature in the heating step is 20 ° C. or higher and 95 ° C. or lower.   The phenol concentration method according to any one of claims 1 to 5, further comprising a water recovery step of recovering a water precipitate after the phenol recovery step.   The phenol concentration method according to any one of claims 1 to 6, further comprising a pretreatment step of treating the phenol-containing mixture using a reverse osmosis membrane before the vaporization step.   The phenol concentration method according to claim 1, wherein the mixture contains an inorganic ionic substance.   The phenol concentration method according to any one of claims 1 to 8, wherein the mixture exhibits alkalinity.

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