JP2017148735A - Solvent separation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an amount of a residual substance contained in a solvent-rich layer in a solvent separation and recovery system using a heat-phase separation substance.SOLUTION: A method of extracting a solvent from a supply flow includes at least: a first separation process in which a solvent-rich first permeation substance flow, which is made by counter-flowing or parallel-flowing a supply flow containing a solvent with a first permeation substance flow containing a heat-phase separation substance having an osmotic pressure through a semi-permeable membrane and in which the solvent is moved to the first permeation substance flow, is heated to a first separation temperature (T1) higher than a temperature (T0) which can thermally separate the heat-phase separation substance and not higher by 30°C than the temperature (T0) which can thermally separate, and is separated into a solvent-rich phase (A1) and a heat-phase separation substance-rich phase (B1); and a second separation process of further heating the B1 phase to a second separation temperature (T2) higher by 20°C and not higher by 115°C than the first separation temperature (T1), and separating into a solvent-rich phase (A2) and a heat-phase separation substance-rich phase (B2).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for separating a solvent from a solution. The present invention is useful for separating water from a solution, for example, and is particularly suitable for separating water from a solution containing an inorganic salt.

  A process for separating and recovering a solvent from a solution containing a solute is widely practiced industrially. The separated high-quality solvent containing no solute is used for, for example, a chemical industrial process. Among the solvents, water is important not only for industrial use but also for agricultural use and beverages. Therefore, a process for separating and purifying water from an aqueous solution containing impurities such as inorganic compounds, organic compounds, and bacteria is required. Water separation and purification methods include distillation and reverse osmosis methods, but distillation methods require enormous heat energy, and reverse osmosis methods have limitations on the concentration of solutes that can be concentrated. Absent. Therefore, a process that can efficiently separate and collect water is desired. In response, water separation and recovery processes using forward osmosis have been studied. For example, a forward osmosis process (for example, Patent Document 1) that uses a thermal phase separation substance as an osmotic substance that draws water from a solution through a membrane by osmotic pressure and separates water by heat, or includes an inorganic compound as an osmotic substance. There is a forward osmosis process (for example, Patent Document 2) that uses a small molecule and then uses a thermal phase separation material for water separation.

US Patent Application Publication No. 2012/0267308 U.S. Pat. No. 8,852,436

As described above, a solvent separation and recovery system using a thermal phase separation material in a forward osmosis process is already known. In general, in a forward osmosis process using a thermal phase separation material, a solvent-rich phase and a thermal phase separation material-rich phase are separated by thermal phase separation. At this time, a part of the thermal phase separation substance remains in the solvent-rich phase, or a small amount of solute that has passed through the semipermeable membrane is dissolved. In particular, in a forward osmosis process using a small molecule containing an inorganic compound as an osmotic substance as in Patent Document 2 and using a thermal phase separation substance for subsequent water separation, the inorganic compound used as the osmotic substance is partially heated. It mixes in the solution containing the phase separation material and dissolves in the solvent rich phase when the thermal phase separation occurs.
The substance remaining in the solvent-rich phase is removed by, for example, a membrane. If the concentration of the remaining substance is high, the amount of energy required to remove the remaining substance increases, or the amount that permeates the purified solvent through the membrane. Or increase. Therefore, in the forward osmosis process using the thermal phase separation material, it is necessary to reduce the amount of the residual material contained in the solvent rich phase.
In addition, in the study by the present inventors, it was found that the inorganic compound dissolved in the solvent-rich phase has an action of promoting the rust generation of the piping particularly when the solvent is water. Thus, it has been found that the suppression is a problem in the chemical industry process.
Therefore, the present invention aims at reducing the amount of residual material contained in the solvent-rich phase in a solvent separation and recovery system using a thermal phase separation material, and in addition, rusting of piping especially when the solvent is water. It aims at providing the water containing the thermal phase separation substance to suppress.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have caused a permeation material flow containing a solvent and a thermal phase separation material to undergo thermal phase separation, and the first solvent-rich phase and the first thermal phase separation material-rich phase After that, it was found that the amount of residual material contained in the second solvent-rich phase can be reduced by re-separating the first thermal phase-separated material-rich phase again at a higher temperature. Moreover, when the solvent was water, it was found that the resulting produced water had a rust preventive effect on the piping, and in addition, it was found to be effective against freezing.
That is, the present invention is as follows.

[1] A supply stream containing a solvent is caused to counter-flow or co-current with a first osmotic substance stream containing a thermal phase separation substance having osmotic pressure through a semipermeable membrane, and the solvent is made to flow into the first osmotic substance. The solvent-rich first osmotic material stream is transferred to a first stream having a temperature not lower than the temperature (T0) at which the thermal phase separation material can be separated by heat and not higher than 30 ° C. at the temperature at which the thermal separation is possible (T0). A first separation step of heating to the separation temperature (T1) to separate the solvent-rich phase (A1) and the thermal phase separation substance-rich phase (B1), and further, the B1 phase to the first separation temperature (T1) At least a second separation step of separating the solvent-rich phase (A2) and the thermal phase separation substance-rich phase (B2) by heating to a second separation temperature (T2) of 20 ° C. or higher and 115 ° C. or lower. Have
Removing the solvent from the feed stream;
[2] The solvent-rich feed stream containing the solvent is caused to counter-flow or co-current with the salt-containing second osmotic material flow through the semipermeable membrane to move the solvent to the second osmotic material flow. The second osmotic material stream is mixed in a state that is incompatible with the first osmotic material stream containing the thermal phase separation material, and the solvent is transferred to the first osmotic material flow to A first osmotic material stream, and the first material stream is heated to a first separation temperature (T1) that is not less than the temperature (T0) at which the thermal phase separation material can be thermally separated and not more than 30 ° C. A first separation step of heating to separate the solvent-rich phase (A1) and the thermal phase separation substance-rich phase (B1);
Further, the previous B1 phase is heated to a second separation temperature (T2) of 20 ° C. or more and 115 ° C. or less of the first separation temperature (T1), and the solvent rich phase (A2) and the thermal phase separation substance rich phase At least a second separation step of separating into (B2),
Removing the solvent from the feed stream;
[3] The method according to [1] or [2], wherein the solvent is water.
[4] The first osmotic substance flow is at least one polymer selected from the group consisting of polyalkylene polymer, polyvinyl alcohol polymer, polyvinyl acetate polymer, acrylic acid polymer, polyacrylamide polymer, ionic liquid polymer, and polyether-modified silicone. The polyalkylene polymer contains at least one species, and the polyalkylene polymer is at least a part selected from the group consisting of polyethylene oxide, polyethylene oxide / polypropylene oxide copolymer, polyethylene oxide / polybutylene oxide copolymer, or a modified hydrophobic group thereof. The method according to any one of [1] to [3], wherein the polymer comprises an ethylene oxide unit.
[5] The method according to any one of [1] to [4], wherein the second osmotic material stream includes at least an inorganic salt or an organic salt selected from a metal salt and / or an ammonium salt.
[6] The second osmotic material stream is sodium hydroxide, sodium carbonate, sodium silicate, sodium sulfate, sodium phosphate, sodium formate, sodium succinate, sodium tartrate, lithium sulfate, ammonium sulfate, ammonium carbonate, ammonium carbamate, sulfuric acid. Zinc, copper sulfate, iron sulfate, magnesium sulfate, aluminum sulfate, sodium chloride, magnesium chloride, disodium monohydrogen phosphate, monosodium dihydrogen phosphate, potassium phosphate, potassium carbonate, manganese sulfate, sodium citrate, thiosulfuric acid The method according to [5], comprising at least the inorganic salt or organic salt selected from the group consisting of sodium and sodium sulfite.
[7] Thermal phase separation substance-containing water containing at least 200 ppm to 20,000 ppm of the thermal phase separation substance and containing 1,000 to 60,000 ppm of the salt.
[8] The thermal phase separation material is at least one polymer selected from the group consisting of polyalkylene polymer, polyvinyl alcohol polymer, polyvinyl acetate polymer, acrylic acid polymer, polyacrylamide polymer, ionic liquid polymer, and polyether-modified silicone. In addition, the polyalkylene polymer is contained in at least a part selected from the group consisting of polyethylene oxide, polyethylene oxide / polypropylene oxide copolymer, polyethylene oxide / polybutylene oxide copolymer, or a hydrophobic group-modified product thereof. The thermal phase separation substance-containing water according to [7], which is a polymer containing an ethylene oxide unit.
[9] The thermal phase separation substance-containing water according to [7] or [8], wherein the salt includes at least an inorganic salt or an organic salt selected from a metal salt and / or an ammonium salt.
[10] The salt is sodium hydroxide, sodium carbonate, sodium silicate, sodium sulfate, sodium phosphate, sodium formate, sodium succinate, sodium tartrate, lithium sulfate, ammonium sulfate, ammonium carbonate, ammonium carbamate, zinc sulfate, sulfuric acid. Copper, iron sulfate, magnesium sulfate, aluminum sulfate, sodium chloride, magnesium chloride, disodium monohydrogen phosphate, monosodium dihydrogen phosphate, potassium phosphate, potassium carbonate, manganese sulfate, sodium citrate, sodium thiosulfate, sulfurous acid The thermal phase separation substance-containing water according to [9], comprising at least an inorganic salt or an organic salt selected from the group consisting of sodium.
[11] A method for producing contained water according to any one of [7] to [10], wherein at least the method according to any one of [1] to [6] is used. .

According to the present invention, since the amount of the remaining substance in the second stage solvent-rich phase (A2) can be reduced by carrying out the two separation steps under specific temperature conditions, the solvent-rich phase may be used depending on the application. Can be used as a product as it is, and even when a process for removing the residual material is performed at a later stage, the concentration of the residual material is low, so that the recovery of the solvent is efficient.
In addition, the water obtained by the solvent removal method of the present invention, including intermediate water, can suppress the rust formation of the piping due to residual salt by allowing the thermal phase separation material to remain in the solvent-rich phase, It also has the effect of preventing the solvent-rich phase from freezing in a low temperature environment.

It is one of the schematic diagrams for demonstrating the system of this invention. It is one of the schematic diagrams for demonstrating the system of this invention.

Hereinafter, the solvent separation and recovery system of the present invention will be described in detail with reference to the drawings.
Hereinafter, an example of the configuration of the solvent separation and recovery system of the present invention will be described with reference to FIG. A feed stream 102 containing solvent 101 is flowed countercurrently or co-currently through a semipermeable membrane 104 with respect to the first osmotic material stream 103 containing the thermal phase separation material, and the solvent 101 into the first osmotic material stream 103. The stream 105 is moved to obtain a stream 105, and the stream 105 is heated by the heat exchanger 106 to a temperature at which the thermal phase separation material is thermally separated, and the first solvent rich stream 108 and the first thermal phase separation substance rich stream are separated in the separation device 107. 109. The first thermal phase separation rich stream 109 is heated to a temperature higher than that of the first stage thermal phase separation process by the heat exchanger 113, and the second solvent rich stream 115 and the second thermal phase separation substance rich stream 116 are separated by the separator 114. And the second solvent-rich stream is purified by filtration membrane 110 to obtain purified solvent 111 and membrane recovery stream 112. The second thermal phase separated material rich stream 116 is reused as the first osmotic material stream 103. At this time, the first solvent rich stream 108 is mixed with the membrane recovery stream 112, for example, but may be mixed directly with the stream 105 or with the feed stream 102. In some cases, the first solvent rich stream 108 may be provided with a separate post-treatment device. The membrane recovery stream 112 is also mixed with, for example, the stream 105, but may be mixed with the second hot phase separated material rich stream 116 or may be mixed with the feed stream 102.

  An example of the configuration of the solvent separation and recovery system of the present invention will be described below with reference to FIG. A feed stream 202 containing solvent 201 is flowed countercurrently or co-currently through a semipermeable membrane 204 with respect to a salt-containing second osmotic material stream 203 to move the solvent 201 to the second osmotic material stream 203. , A flow 205 is brought into contact with the first osmotic material stream 206 containing the thermal phase separation material, and the second osmotic material stream 203, the first osmotic material stream 206 and the solvent 201 are separated in the separation device 207. Is separated into a stream 208 and heated to a temperature at which a heat phase is separated by a heat exchanger 209, and a first solvent rich stream 211 and a first osmotic substance stream (first thermal phase separated substance rich stream) 212 are separated by a separation device 210. To separate. The first thermal phase separation material rich stream 212 is heated again to a temperature higher than that in the first stage thermal phase separation process by the heat exchanger 216, and the second solvent rich stream 218 and the second thermal phase separation material are separated by the separation device 217. Separated into a rich stream 219, the second thermal phase separated material rich stream 219 is reused as the first osmotic material stream 206, and the second solvent rich stream 218 is purified by the filtration membrane 213 to be purified solvent 214 and membrane recovery stream 215. Get. At this time, the first solvent-rich stream 211 is mixed with, for example, the membrane recovery stream 215, but may be mixed directly with the stream 205 or with the feed stream 202. In some cases, the first solvent-rich stream 211 may be provided with another post-treatment device. The membrane recovery stream 215 is also mixed with, for example, the stream 205, but may be mixed with the stream 208, may be mixed with the feed stream 202, and in some cases, another post-processing device may be provided.

The solvent in the present invention is an inorganic solvent or an organic solvent, preferably water. The solute that constitutes the feed stream with the solvent is selected from inorganic and organic compounds and may be a liquid. Examples of the supply stream that is a liquid include various wastewaters such as life, mining, agriculture, and industry, seawater, and accompanying water that is produced as a result of the production of oil and gas.
The semipermeable membrane has pores of a size that allows the solvent to pass but not the solute. A reverse osmosis membrane can also be used, but a forward osmosis membrane is preferred. The material of the membrane is not particularly limited, and examples thereof include cellulose acetate, polyamide, polybenzimidazole, and polyvinyl alcohol. The form of the semipermeable membrane and the form of the membrane module are not particularly limited, and in the form of the semipermeable membrane, any of a flat membrane, a hollow fiber membrane, etc. may be used. A hollow fiber membrane is preferred from the viewpoint of effective use of the membrane. In the form of the membrane module, any of a plate and frame type, a hollow fiber type, a spiral type and the like may be used. A forward osmosis process is adopted as a method of permeating the solvent. The membrane surface through which the osmotic material flow flows may be on the active layer side or on the opposite side of the active layer.

  For the permeate stream containing salt as the main component of the solute, for example, sodium hydroxide, sodium carbonate, sodium silicate, sodium sulfate, sodium phosphate, sodium formate, sodium succinate, sodium tartrate, lithium sulfate, ammonium sulfate, ammonium carbonate , Ammonium carbamate, zinc sulfate, copper sulfate, iron sulfate, magnesium sulfate, aluminum sulfate, sodium chloride, magnesium chloride, disodium monohydrogen phosphate, monosodium dihydrogen phosphate, potassium phosphate, potassium carbonate, manganese sulfate, Sodium citrate, sodium thiosulfate, sodium sulfite and the like can be used. These penetrating substances can be used alone or in combination.

  The thermal phase separation substance in the present invention refers to a substance that is phase-separated from the solvent by heating a solution dissolved in the solvent. In addition, the solvent-rich in the present invention refers to a solution having a lower concentration of the thermal phase separation substance among the two-phase solutions subjected to the thermal phase separation, and a solution having a higher concentration of the thermal phase separation substance is subjected to the thermal phase separation. A substance-rich solution.

As the thermal phase separation material in the present invention, polyalkylene polymer, polyvinyl alcohol polymer, polyvinyl acetate polymer, acrylic acid polymer, polyacrylamide polymer, ionic liquid polymer, polyether-modified silicone and the like can be used. The polyalkylene polymer is a polymer containing at least a part of an ethylene oxide unit, such as polyethylene oxide, polyethylene oxide / polypropylene oxide copolymer, polyethylene oxide / polybutylene oxide copolymer, or a modified hydrophobic group thereof. It is done. Hydrophobic groups include hydrocarbon groups. These thermal phase separation materials can be used alone or in combination.
In the present invention, the process using a semipermeable membrane uses a forward osmosis process, and therefore the forward osmosis process will be described as an example.
In the forward osmosis process, an osmotic flow having a higher osmotic pressure than the feed flow needs to flow through the semipermeable membrane. At this time, if the osmotic pressure is high, the feed stream can be concentrated to a high concentration. By concentrating the feed stream to a high concentration, the amount of the concentrated feed stream that is discharged can be reduced. Therefore, it is preferable that the concentration rate of the feed stream is high, and that the feed stream is concentrated at least twice. In addition, if the difference in osmotic pressure between the supply flow and the osmotic substance flow is large, the permeation rate of the solvent that permeates the membrane increases, so that the membrane area can be reduced and the equipment cost can be reduced. For the above reasons, it is better that the osmotic pressure of the osmotic substance flow is high.
For example, in the case of the process of FIG. 2, when recovering water from seawater, if the concentration rate of the feed stream is doubled, the osmotic pressure of the concentrated feed stream is about 60 atm, but the water is moved through the semipermeable membrane. The osmotic pressure of the first osmotic material flow is preferably 80 atm or more in order to secure the driving force for driving and the driving force for moving water from the second osmotic material flow to the first osmotic material flow. When processing a supply stream containing a high salt concentration, such as associated water in an oil field or gas field, for example, a supply stream having a salt concentration of 8 wt%, the driving force for moving the water by doubling the concentration rate of the supply stream Is ensured, the osmotic pressure of the first osmotic material flow is preferably 145 atm or more. As described above, the osmotic pressure of the first osmotic material flow is preferably higher, but on the other hand, in order to regenerate the first osmotic material flow having a high osmotic pressure, high energy is required. The osmotic pressure is preferably 250 atm or less, more preferably 200 atm or less, and further preferably 175 atm or less.

From the viewpoint of separability when performing solution separation, the viscosity of the thermal phase separation substance is preferably 250 mPa · s or less, and more preferably 100 mPa · s or less. The viscosity in the present invention is a value obtained by measuring a 90 wt% aqueous solution of a thermal phase separation substance at 30 ° C. using a cone of R24 at an angle of 1 ° 34 ′ in a viscometer TVL-33L (Toki Sangyo Co., Ltd.). Means.
The osmotic material can be used as it is as the osmotic material flow, but a solution dissolved in an appropriate solvent can also be used as the osmotic material flow. The solvent used here is preferably compatible with the solvent to be separated and recovered, and more preferably the same substance. The osmotic pressure of the osmotic flow is set to be higher than the feed flow.

  When the solvent is moved by directly contacting the second osmotic material stream containing the salt and the first osmotic material stream containing the thermal phase separation material, mixing may be performed. For example, line mixing may be performed or a mixer may be used. Separation is performed after the contact, and for example, gravity sedimentation or centrifugation may be used. Contact and separation may be performed simultaneously by countercurrent extraction, and the contact or mixing and separation process may be performed multiple times.

In the membrane filtration of the solvent-rich flow after the thermal phase separation, for example, ultrafiltration may be performed, or microfiltration, nanofiltration, or reverse osmosis filtration may be performed. However, from the viewpoint of the quality of the purified solvent, it is desirable that 90% or more of the residual material in the solvent-rich stream is preferably blocked by the filtration membrane. From the viewpoint of solvent recovery efficiency, the purified solvent recovered by membrane filtration is preferably 50%, more preferably 70%, and even more preferably 90% or more of the solution supplied to the filtration membrane. desirable.
The thermal phase separation of the thermal phase separation material-rich flow may be two stages, three stages or more, but is preferably two stages from the viewpoint of equipment scale.

In the present invention, the heat-separable temperature (T0) means that the solvent-rich first osmotic material stream is heated while stirring in a small glass reactor TEM-V (Pressure-resistant Glass Industry Co., Ltd.), and stirring is stopped. It refers to the temperature at which droplets coalesced with the upper phase of the solution can be visually confirmed when allowed to stand for 10 minutes.
An object of the present invention is to reduce the amount of residual substances contained in the solvent-rich phase by performing thermal phase separation in multiple stages. Most of the residual material contained in the solvent-rich phase is material (eg, inorganic salts) that was dissolved in the solvent-rich first osmotic material stream. It is considered that when the first osmotic material stream is separated into a solvent-rich phase and a thermal phase separation material-rich phase, the first osmotic material stream is distributed according to the amount of solvent in each phase and is in an equilibrium state. That is, the substance dissolved in the first osmotic substance stream is easily distributed to the solvent-rich phase of the two phases subjected to the thermal phase separation. Therefore, in the present invention, in the first stage thermal phase separation, the remaining substance is distributed to the solvent rich phase (A1), and the thermal phase separation substance rich phase obtained in the first stage in the second stage thermal phase separation. The object is achieved by phase-separating (B1) to obtain a solvent-rich phase (A2) in which the concentration of the remaining substance is reduced.

Since the solvent-rich phase (A1) taken out in the first stage thermal phase separation only needs to have a sufficient amount of solvent to dissolve the remaining substances, the first separation temperature (T1) is the temperature at which heat separation is possible. (T0) or more is sufficient. On the other hand, when the first separation temperature (T1) is set to a temperature considerably higher than the temperature (T0) at which heat separation is possible, the solvent-rich phase (A1) increases, and the water recovery rate decreases. Therefore, the first separation temperature (T1) is preferably T0 or more and T0 + 30 ° C or less, and more preferably T0 or more and T0 + 20 ° C or less.
The solvent rich phase (A2) taken out in the second stage thermal phase separation is obtained by treating the thermal phase separated substance rich phase (B1) obtained in the first stage at a temperature sufficiently higher than the first separation temperature (T1). Thus, the water recovery rate can be increased. However, when the thermal phase separation temperature is too high, there are problems such as an increase in equipment cost to secure pressure resistance performance and an increase in energy loss due to heat dissipation. Therefore, the second separation temperature (T2) is preferably T1 + 20 ° C. or higher and T1 + 115 ° C. or lower, and more preferably T1 + 30 ° C. or higher and T1 + 90 ° C. or lower.

The concentration of the thermal phase separation substance in the water containing the thermal phase separation substance, which is a solvent-rich flow obtained in the present invention, is preferably 200 ppm or more and 20,000 ppm or less. As a result of the study by the present inventors, it has been confirmed that the presence of the salt in the contained water, which will be described later, has the effect of preventing the freezing as well as the effect of rust generation on the piping. It was found that the thermal phase separation substance contained in the water contained in the present invention has an effect of suppressing the rust generation of the pipe due to the salt due to the influence of the salt. As for the above effect, the polymer (thermal phase separation substance) concentration is preferably 200 ppm or more at the lower limit, more preferably 500 ppm or more, still more preferably 1,000 ppm or more, and particularly preferably 2,500 ppm or more. On the other hand, the polymer (thermal phase separation substance) concentration is sufficient if it is 20,000 ppm or less, more preferably 10,000 ppm or less, still more preferably 5,000 ppm, and 4,000 ppm or less. It is particularly preferred. The thermal phase separation substance has a freezing prevention effect due to a sufficient freezing point depression even in the above concentration range, and when the upper limit is 20,000 ppm or less, the viscosity of water containing the thermal phase separation substance does not become excessively high. Even if a purification process (for example, a filtration process using a nanofilter) is performed, it can be easily performed, which is preferable.
Examples of the thermal phase separation substance in water containing the thermal phase separation substance in the present invention include polyalkylene polymers, polyvinyl alcohol polymers, polyvinyl acetate polymers, acrylic acid polymers, polyacrylamide polymers, ionic liquid polymers, polyether-modified silicones, and the like. The polyalkylene polymer is a polymer containing at least a part of an ethylene oxide unit, such as polyethylene oxide, polyethylene oxide / polypropylene oxide copolymer, polyethylene oxide / polybutylene oxide copolymer, or a modified hydrophobic group thereof. It is done. Hydrophobic groups include hydrocarbon groups. These thermal phase separation materials are used alone or as a mixture.

The salt concentration in the water containing the thermal phase separation substance is preferably 0.1 wt% or more and 6.0 wt% or less. When the salt is contained in the contained water within the above range, the freezing point of the contained water is lowered and the freezing effect has been found by the present inventors. Therefore, the lower limit of the salt concentration is 0.1 wt% or more, preferably 0.6 wt% or more, more preferably 1.0 wt% or more.
On the other hand, the presence of salt in the contained water has been confirmed by the study of the present invention to cause rusting of the piping, so the upper limit of the salt concentration is preferably 6.0 wt% or less, more preferably 3.5 wt%. % Or less. Moreover, when 3.5 wt% or less is further purified in the subsequent membrane separation step, the filtration pressure can be set to an appropriate value.

The salt in the water containing the thermal phase separation substance is a salt containing at least an inorganic salt or an organic salt selected from metal salts and / or ammonium salts, such as sodium chloride, sodium hydroxide, sodium carbonate, sodium silicate, sulfuric acid. Sodium, sodium phosphate, sodium formate, sodium succinate, sodium tartrate, lithium sulfate, ammonium sulfate, ammonium carbonate, ammonium carbamate, zinc sulfate, copper sulfate, iron sulfate, magnesium sulfate, aluminum sulfate, magnesium chloride, disodium phosphate It is a salt containing at least an inorganic salt or an organic salt selected from the group consisting of monohydrogen, monosodium dihydrogen phosphate, potassium phosphate, potassium carbonate, manganese sulfate, sodium citrate, sodium thiosulfate, and sodium sulfite.

Examples of the present invention will be specifically described below, but the present invention is not limited to them.
In the following examples, water was used as a solvent, AH-0673A (Toho Chemical Co., Ltd.) was used as a thermal phase separation substance, and ammonium sulfate (Wako Pure Chemical Industries, Ltd.) was used as an inorganic salt. The concentration of the thermal phase separation substance in the solution was measured by the refractive index using PAL-RI manufactured by Atago Co., Ltd. The concentration of ammonium sulfate in the solution was measured by titration using a barium chloride solution (Sigma Aldrich Co.) and Alizarin Red S (Sigma Aldrich Co.) solution, and the titration end point was determined by visual observation of a change in color tone.
A solution containing 63.5 wt% AH-0673A and 0.60 wt% ammonium sulfate is obtained as a solvent-rich first osmotic material stream, and is 20 with respect to AH-0673A heat separable temperature (T0, 60 ° C.). A hot phase separation was performed at 80 ° C., which is a high temperature, and a first hot phase separation material-rich stream was subjected to a thermal phase separation at 150 ° C. As a comparative example, a solution containing 63.5 wt% AH-0673A and 0.60 wt% ammonium sulfate was subjected to thermal phase separation at 80 ° C. and 150 ° C., respectively.

For example, in FIG. 2, the water recovery rate was obtained by the thermal phase separation process among the solvents contained in 1 kg of the solvent-rich first osmotic material stream (flow 208) entering the first stage thermal phase separation process. It refers to the ratio of the solvent weight of the solvent rich phase.

Water recovery (%) = 100 × (solvent weight of solvent-rich phase obtained from 1 kg of first osmotic material stream) / (solvent weight contained in 1 kg of solvent-rich first osmotic material stream)

That is, in the separation methods A and B, since the thermal phase separation is one stage, out of the solvent contained in 1 kg of the first osmotic material stream, the solvent rich phase (A1, That is, the ratio of the solvent weight of 211). In the separation methods C, D, and E, the thermal phase separation process is a two-stage process, so that among the solvents contained in 1 kg of the first osmotic material stream, the solvent rich phase (A2) obtained from 1 kg of the first osmotic material stream. I.e. the proportion of the solvent weight of 218).
The salt removal rate is calculated from the weight of inorganic salt (ammonium sulfate) contained in 1 kg (208) of the solvent-rich first osmotic material stream entering the first-stage thermal phase separation process to the solvent-rich phase obtained by the thermal phase separation process. The value obtained by subtracting the amount of inorganic salt contained, and dividing the value after the reduction by the amount of inorganic salt contained in 1 kg (208) of the solvent-rich first osmotic material stream entering the first stage thermal phase separation process is 100. Multiplied by.

Salt removal rate (%) = 100 × {(weight of inorganic salt contained in 1 kg of solvent-rich first osmotic substance stream) − (weight of inorganic salt contained in solvent-rich phase obtained from 1 kg of first osmotic substance stream) )} / (Weight of inorganic salt contained in 1 kg of solvent-rich first osmotic stream)

In the separation methods A and B, the solvent-rich phase means a solvent-rich phase (A1, ie 211), and in the separation methods C, D and E, the solvent-rich phase is a solvent-rich phase (A2, ie 218). Means.
As for the water recovery rate and salt removal rate in FIG. 1, 1 kg of the solvent-rich first osmotic material flow entering the first stage thermal phase separation flow is flow 105, A1 is flow 108, and A2 is The flow of reference numeral 115 was obtained in the same manner as in the case of FIG.

When the thermal phase separation was performed at 150 ° C. in one stage, the recovery rate of water was as high as 63.6%, but the salt in the feed stream to the thermal phase separation process could not be removed (less than 5%). When the thermal phase separation was performed at 80 ° C. in one stage, the water recovery rate was moderate at 24.5%, but the salt removal rate was still low at 14.9%. In contrast, as shown in the examples, when two-stage thermal phase separation was performed at 80 ° C. and 150 ° C., the water recovery rate was 36.7%, and the salt removal rate was 86. High production water of 0% could be obtained.
When two-stage thermal phase separation was performed at 80 ° C. and two-stage thermal phase separation was performed at 150 ° C., the water recovery rate was very low.

Table 2 shows the results of the first-stage thermal phase separation (thermal phase separation at 80 ° C. in the example and 150 ° C. in the comparative example).
The concentration of AH-0673A in the first hot phase separated substance-rich stream in the comparative example was 81.2 wt%, and the concentration in the example was 68.7 wt%. Moreover, the AH-0673A density | concentration of the 1st solvent rich stream in a comparative example was 3.7 wt%, and the density | concentration in an Example was 9.8 wt%. The thermal phase separation temperature of the comparative example and the example in the first stage thermal phase separation process is different, and the thermal phase separation temperature is higher in the comparative example, so the concentration of the thermal phase separation material in the hot phase separation rich flow is higher. Thus, the concentration of the thermal phase separation material in the solvent-rich stream is lowered. This is a phenomenon generally understood for a thermal phase separation material exhibiting a lower critical solution temperature (LCST).

  For the examples, the first hot phase separation material rich stream was heated to 150 ° C. to obtain a second solvent rich stream and a second hot phase separation material rich stream. The respective concentrations are shown in Table 3. The concentration of ammonium sulfate contained in the second solvent-rich stream is 0.64 wt%, which is a value equal to or less than 1/4 compared with 2.73 wt% of the comparative example in which the thermal phase separation is performed in one stage at 150 ° C. . In addition, the concentration of AH-0673A contained in the second solvent rich stream in the examples was 1.6 wt%. This is a value of ½ or less compared to 3.7 wt% of the comparative example in which the thermal phase separation was performed in one stage at 150 ° C., and greatly reduced the thermal phase separation material in the solvent-rich flow. You can see that

  As described above, by using the present invention, in the solvent recovery process using the thermal phase separation material, the amount of the residual material contained in the solvent rich stream can be reduced, thereby recovering the solvent more efficiently than before. can do.

Rust generation cannot be confirmed even when water containing a heat phase separation material containing 1.6 wt% of AH-0673A as a heat phase separation material and 0.64 wt% of ammonium sulfate as an inorganic salt is exposed to a pipe made of SUS316 for 10 days. It was.
Even if the water containing the heat phase separation substance containing 1.6 wt% of AH-0673A as the heat phase separation substance and 0.64 wt% of ammonium sulfate as the inorganic salt is allowed to stand in an environment of −0.1 ° C. for 12 hours or more, it solidifies. I did not.

  The present invention is a solvent separation and recovery system using a thermal phase separation substance, which provides efficient solvent recovery by reducing the membrane filtration load in the subsequent stage and increasing the concentration rate of the feed stream. is there. The present invention can be suitably used in fields such as desalination of seawater, regeneration of domestic wastewater, regeneration of factory wastewater, and recovery of water from associated water in oil and gas fields.

DESCRIPTION OF SYMBOLS 101 Solvent 102 Supply stream 103 First osmotic material stream containing thermal phase separation material 104 Semipermeable membrane 105 Flow composed of solvent 101 and first osmotic material stream 103 106 Heat exchanger 107 Separator 108 First solvent rich stream 109 First Thermal phase separation substance rich stream 110 Filtration membrane 111 Purified solvent 112 Membrane recovery stream 113 Heat exchanger 114 Separation device 115 Second solvent rich stream 116 Second thermal phase separation substance rich stream 117 Concentrated supply stream 201 Solvent 202 Supply stream 203 Salt A second osmotic material stream 204 comprising a semi-permeable membrane 205 a stream composed of a solvent 201 and a second osmotic material stream 203 206 a first osmotic material stream 207 containing a thermal phase separation material 207 a separator 208 comprising a second osmotic material stream 206 and a solvent 201 Stream 209 Heat exchanger 210 Separator 211 First solvent rich stream 212 First thermal phase separation material li It flows 213 filtration membrane 214 purified solvent 215 film recovery flow 216 heat exchanger 217 separator 218 second solvent-rich stream 219 second thermal phase separation material rich stream 220 enriched feed stream

Claims (11)

The solvent-containing feed stream is counter-flowed or co-flowed with the first osmotic material stream containing the thermal phase separation material having osmotic pressure through the semipermeable membrane, and the solvent is transferred to the first osmotic material stream. A first separation temperature that is not less than the temperature (T0) at which the thermal phase separation material can be separated by heat and the temperature (T0) at which the thermal separation can be performed (T0) is 30 ° C. or less. A first separation step of heating to T1) and separating the solvent-rich phase (A1) and the thermal phase separation substance-rich phase (B1);
Furthermore, the B1 phase is heated to a second separation temperature (T2) of 20 ° C. or more and 115 ° C. or less of the first separation temperature (T1), and the solvent rich phase (A2) and the thermal phase separation substance rich phase At least a second separation step of separating into (B2),
Removing the solvent from the feed stream; A solvent-containing feed stream is countercurrently or cocurrently flowed through the semipermeable membrane with a salt-containing second osmotic material stream to move the solvent into the second osmotic material stream, and the solvent rich second. The solvent-rich first osmotic material is prepared by mixing the osmotic material stream in an incompatible state with the first osmotic material stream containing the thermal phase separation material and transferring the solvent to the first osmotic material stream. The first osmotic material stream is heated to a first separation temperature (T1) that is not less than the temperature (T0) at which the thermal phase separation material can be thermally separated and not more than 30 ° C. that is the temperature at which the heat separation is possible (T0). A first separation step of separating the solvent rich phase (A1) and the thermal phase separation substance rich phase (B1),
Furthermore, the B1 phase is heated to a second separation temperature (T2) of 20 ° C. or more and 115 ° C. or less of the first separation temperature (T1), and the solvent rich phase (A2) and the thermal phase separation substance rich phase At least a second separation step of separating into (B2),
Removing the solvent from the feed stream;   The extraction method according to claim 1 or 2, wherein the solvent is water.   The first osmotic material stream includes at least one polymer selected from the group consisting of a polyalkylene polymer, a polyvinyl alcohol polymer, a polyvinyl acetate polymer, an acrylic acid polymer, a polyacrylamide polymer, an ionic liquid polymer, and a polyether-modified silicone. And the polyalkylene polymer is an ethylene oxide unit in at least a part selected from the group consisting of polyethylene oxide, polyethylene oxide / polypropylene oxide copolymer, polyethylene oxide / polybutylene oxide copolymer, or a modified hydrophobic group thereof. The method according to any one of claims 1 to 3, wherein the polymer comprises a polymer.   The method according to any one of claims 1 to 4, wherein the second osmotic substance stream contains at least an inorganic salt or an organic salt selected from metal salts and / or ammonium salts.   The second osmotic material stream is sodium hydroxide, sodium carbonate, sodium silicate, sodium sulfate, sodium phosphate, sodium formate, sodium succinate, sodium tartrate, lithium sulfate, ammonium sulfate, ammonium carbonate, ammonium carbamate, zinc sulfate, sulfuric acid Copper, iron sulfate, magnesium sulfate, aluminum sulfate, sodium chloride, magnesium chloride, disodium monohydrogen phosphate, monosodium dihydrogen phosphate, potassium phosphate, potassium carbonate, manganese sulfate, sodium citrate, sodium thiosulfate, sulfurous acid The method according to claim 5, comprising at least the inorganic salt or organic salt selected from the group consisting of sodium.   A thermal phase separation substance-containing water containing at least the thermal phase separation substance at 200 ppm to 20,000 ppm and the salt at 1,000 ppm to 60,000 ppm.   The thermal phase separation material contains at least one polymer selected from the group consisting of polyalkylene polymer, polyvinyl alcohol polymer, polyvinyl acetate polymer, acrylic acid polymer, polyacrylamide polymer, ionic liquid polymer, polyether-modified silicone, In addition, the polyalkylene polymer has an ethylene oxide unit in at least a part selected from the group consisting of polyethylene oxide, polyethylene oxide / polypropylene oxide copolymer, polyethylene oxide / polybutylene oxide copolymer, or a modified group thereof. The thermal phase-separated substance-containing water according to claim 7, which is a polymer containing.   The thermal phase separation substance-containing water according to claim 7 or 8, wherein the salt includes at least an inorganic salt or an organic salt selected from a metal salt and / or an ammonium salt.   The salt is sodium hydroxide, sodium carbonate, sodium silicate, sodium sulfate, sodium phosphate, sodium formate, sodium succinate, sodium tartrate, lithium sulfate, ammonium sulfate, ammonium carbonate, ammonium carbamate, zinc sulfate, copper sulfate, sulfuric acid Iron, magnesium sulfate, aluminum sulfate, sodium chloride, magnesium chloride, disodium monohydrogen phosphate, monosodium dihydrogen phosphate, potassium phosphate, potassium carbonate, manganese sulfate, sodium citrate, sodium thiosulfate, sodium sulfite The water containing a thermal phase separation substance according to claim 9, comprising at least an inorganic salt or an organic salt selected from the group.   It is a manufacturing method of the contained water in any one of Claims 7-10, Comprising: The manufacturing method of the contained water using at least the method as described in any one of Claims 1-6.

Images