JP2002336681A - Gas-liquid contact apparatus and freezing concentration separation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a gas-liquid contact apparatus which maintains solvent absorption efficiency and increases the concentration of a solvent in finally discharged water by reducing the quantity of water to be replenished. SOLUTION: Before the water in which the solvent in gas is absorbed is discharged from a treating tank 14 and sent to a freezing apparatus, initial ice C1 in which the solvent is hardly contained is formed on a cooled surface with fresh water. When the water containing the solvent is introduced on the initial ice C1, the solvent is not frozen but water is frozen to form ice of nearly pure water due to the difference of the freezing point. Because the initial ice C1 has a smoothed surface free from ruggedness, the ice plate C2 formed on the surface of the initial ice C1 hardly contains the solvent. The ice is melted to be recycled in the treating tank 14 to reduce the use quantity of the fresh water. The solvent in the unfrozen water separated from the water has high concentration and the water in which the concentration of the solvent is increased, is used for a detergent, fuel or a coating liquid to be applied to a planographic printing plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-liquid contacting device for recovering, for example, volatile organic compound (VOC) gas discharged from a plant or the like into the atmosphere, and a freeze concentration separation method.

[0002]

2. Description of the Related Art As shown in FIG. 6, water used in a water spray type gas-liquid contacting device 158 for absorbing and processing VOC gas G discharged from a plant or the like to the atmosphere is supplied to processing towers 160 and 16.
In 2 and 164, the solvent concentration gradually increases due to contact with the gas. When the water that has absorbed the solvent is returned to the processing tanks 166, 168, and 170 as it is, the concentration of the solvent in the water in the entire processing tank increases. Cannot absorb solvent (solvent collection efficiency is reduced).

Therefore, in order to maintain the solvent absorption efficiency, it is necessary to continuously supply fresh water W from the water pipe 172 to the treatment tank 170, and it is not possible to reduce the amount of replenishing water.

[0004] Further, it is determined how high the concentration of the solvent contained in the water W1 finally discharged from the drain pipe 174 of the treatment tank 166 of the water spray type gas-liquid contacting device 158 is, and how the solvent is distilled and reused. This is a major point in reducing running costs.

Accordingly, the present applicant has proposed a gas-liquid contacting device that separates water that has absorbed a solvent into ice and concentrated water containing a solvent by using a freeze-concentrating / separating device (Japanese Patent Application No. 200-131).
0-074783).

By using this gas-liquid contact device, the amount of replenishing water can be reduced, the solvent absorption efficiency can be maintained, and the concentration of the solvent contained in the finally discharged water can be increased. However, it is necessary to devise a little more in order to prevent the solvent from being contained in the ice during the freeze concentration separation.

[0007]

SUMMARY OF THE INVENTION In view of the above facts, the present invention regulates freezing conditions when freezing water that has absorbed a solvent, thereby making ice containing as little solvent as possible. And reduce the amount of makeup water.

[0008]

According to a first aspect of the present invention, there is provided a processing tower into which a gas is introduced from a gas generating source, a processing tank for supplying water to the processing tower and refluxing water having absorbed a solvent. A gas-liquid contact unit composed of, a freezing means for freezing water containing a solvent drained from the processing tank, and a recycling means for melting the ice frozen by the freezing means and sending water to the processing tank, The cooling surface of the freezing means, to which the water containing the solvent freezes and adheres, is smoothed.

In the above configuration, the water having absorbed the solvent in the gas is drained from the treatment tank and sent to the freezing means. When the freezing means freezes the water containing the solvent, the water does not freeze due to the difference in the freezing point, and the water freezes to become ice close to pure water.

Since the cooling surface of the freezing means to which the water containing the solvent freezes and adheres is smoothed, the solvent is taken in at the time of freezing as compared with the cooling surface having unevenness or cracks on the surface. Because it is difficult, beautiful ice is made. Then, the recycling means melts the ice containing little solvent and sends it to the processing tank, and again contacts the gas introduced into the processing tower to absorb the solvent in the gas. In this way, the amount of fresh water to be supplied to the treatment tank can be reduced by melting and reusing clean ice as water.

Further, the concentration of the solvent of the unfrozen water separated from the water is concentrated and higher than that of the conventional gas-liquid contacting device. It can also be used as a fuel and a coating liquid for applying to a lithographic printing plate.

According to a second aspect of the present invention, as means for smoothing the cooling surface, clear water having a low solvent content is sent to the freezing means to form initial ice on the surface of the cooling surface. .

In the above configuration, by sending clear water having a low solvent content to the freezing means, ice without irregularities or cracks on the surface of the cooling surface is formed as initial ice. By flowing treated water containing a solvent over the surface of the initial ice, ice that hardly takes in the solvent is made, and the solvent and water can be separated efficiently.

The invention according to claim 3 is characterized in that the concentration of the solvent contained in the fresh water is 500 ppm or less.

According to a fourth aspect of the present invention, the temperature of water containing a solvent to be introduced into the freezing means in which initial ice is formed on the surface of the cooling surface is set to 5 ° C. or less.

In the above configuration, the temperature of the water containing the solvent introduced into the freezing means is set to 5 ° C. or less, so that the surface of the initial ice is melted and irregularities and cracks are not generated. Ice containing almost no solvent is produced.

According to a fifth aspect of the present invention, there is provided a freeze-concentration / separation method in which water containing a solvent is frozen by a freezing device and separated into ice and a concentrated solution having a high solvent concentration. In this method, initial ice is formed with clear water, and water containing a solvent is made on the surface of the initial ice to separate it into ice and a concentrated liquid.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, the gas-liquid contact device 10 according to the present embodiment includes a gas-liquid contact unit 30 composed of a processing tower 12 and a processing tank 14.

In the processing tank 14 of the gas-liquid contact unit 30,
A supply pipe 24 is connected. The supply pipe 24 is provided with a pump 20. By operating the pump 20, fresh water and recycle water described later are supplied from the storage tank 52 as treated water. A liquid supply pump 28 is provided in a water supply pipe 26 connected to the side wall of the processing tank 14, and water is pumped to the top of the processing tower 12. Processing tower 1
The water pumped to the top of 2 is sprinkled downward by a sprinkler 32.

A gas pipe 34 for taking in a volatile organic compound (VOC) gas discharged from the plant P is connected to the outer peripheral wall of the processing tower 12, and the VOC gas is continuously introduced into the processing tower 12. Is sent.

The VOC gas taken into the processing tower 12 from the gas pipe 34 comes into contact with the water sprinkled by the sprinkler 32 while being raised, and is batch-processed, so that the concentration of the contained solvent is reduced. Then, the VOC gas that has come into contact with water is released to the atmosphere as a gas that does not affect the environment through an exhaust pipe 40 connected to the top of the processing tower 12.

A drain pipe 44 is connected to the processing tank 14. The drain pipe 44 is provided with an electromagnetic valve 78. By operating the electromagnetic valve 78, water in the processing tank 14 is drained to the intermediate tank 16.

The amount of water supplied to the processing tank 14 from the supply pipe 24 and the amount of water drained from the processing tank 14 are substantially the same, so that the solvent can be recovered without stopping the VOC gas in batch processing. It has become.

On the other hand, a concentration sensor 80 is provided in the processing tank 14, detects the solvent concentration in the processing tank 14, and sends a signal to the control unit 84. The control unit 84 is connected to the electromagnetic valve 78 and the pump 20, and replaces water in the processing tank 14 based on the detection result of the concentration sensor 80.

Here, when the concentration of the solvent in the water in the processing tank 14 detected by the concentration sensor 80 exceeds a predetermined value, the pump 2
0, and fresh water is supplied to the treatment tank 1 through the supply pipe 24.
At the same time, the electromagnetic valve 78 is opened, and water having a high solvent concentration is drained from the drain pipe 44 to replace the processing tank 14 with fresh water.

By repeating the above operation,
The solvent in the VOC gas can be collected with high efficiency, and the solvent concentration of the drained water becomes high. For this reason, the recovery efficiency in the next step is increased, and equipment costs and running costs can be reduced.

As the gas-liquid contact method, a water spray method,
Although the filling method is known, the method is not specified. The number of gas-liquid contact units is not limited to one as in the present embodiment, but may be plural.

Further, the concentration of the volatile organic compound gas to be treated is preferably 100 ppm or more,
At pm or more, the effect appears remarkably. Further, as a type of the solvent gas, a difference in solubility parameter with water is 19 (cal ·
cm ⁻³ ) within ^1/2 , preferably 15 (cal · cm ⁻³ )
More preferably within ^1/2 (solubility parameter: Hild)
ebrand dissolution parameters).

Further, the solvent of the volatile organic compound is not limited to methyl ethyl ketone as long as it is water-soluble. Alcohols such as methanol, ethanol and n-propanol, polyhydric alcohols such as ethylene glycol, acetone, methyl Ketones such as acetone and cyclohexane, and esters such as methyl formate, ethyl formate, methyl acetate, ethyl acetate, and ethyl lactate may be used. further,
It can be treated with mixed solvent gas.

Further, the temperature of the replenished water is preferably 30 ° C. or lower, more preferably 15 ° C. or lower. The solvent concentration of the replenished water is preferably 2000 ppm or less. Furthermore, in this example, water was used as the treated water for recovering the solvent in the VOC gas, but the same effect can be obtained with activated sludge containing sludge water or microorganisms.

Next, how to use the waste water of one batch stored in the intermediate tank 16 as recycled water will be described.

A water supply pipe 94 of a fresh water tank 90 in which fresh water is stored is connected to the electromagnetic switching valve 18. By switching the electromagnetic switching valve 18, fresh water is sent from the fresh water tank 90 to the freezing device 22. Alternatively, water containing a solvent stored in the intermediate tank 16 is sent to the freezing device 22.

The freezing device 22 includes a tubular cooling pipe 36 connected in a ring shape. Water or fresh water containing a solvent is supplied to the cooling pipe 36 from a supply pipe 38. Then, the water in the cooling pipe 36 is circulated along the cooling surface 36A (see FIG. 3) at the set flow velocity by the circulation pump 42 whose driving force is controlled by the control unit 84.

The vertical portion of the cooling pipe 36 is cooled by a cooling coil 46 through which a refrigerant circulates, and is shown in FIGS.
As shown in (C), an initial ice C (described later) is formed on the cooling surface 36A.
1 and an ice plate C2 are formed.

An opening / closing door 48 is provided below the cooling pipe 36.
Are provided so that the initial ice C1 and the ice plate C2 can be taken out. The unfrozen water in the cooling pipe 36 is
It is sent to the still 64 through the drain pipe 50.

On the other hand, the initial ice C1 and the ice plate C2 containing almost no solvent removed from the freezing device 22 are temporarily stored in the ice storage tank 56 through the input pipe 54, and thereafter, are cooled with cold water (or mixed ice particles). Chilled water pipe 6 with pump 58
2 to the heat exchanger 60. Thus, by storing ice and supplying it as cold water, stable supply of the refrigerant to the heat exchanger 60 becomes possible. This heat exchanger 60 is
It uses the cold heat of cold water, and is used for air conditioning in factories and the like.

Further, the cold water (water containing almost no solvent) heat-exchanged in the heat exchanger 60 is sent to the storage tank 52 as recycled water, and sent again to the processing tank 14.

On the other hand, the water containing the high-concentration solvent discharged from the freezing device 22 is sent to the still 64. The distillation device 64 separates the solvent and the water by vaporization by utilizing the difference in boiling point between the solvent and the water. Water containing a high concentration of the solvent is supplied to the distillation column 66 from the supply port 68. Distillation tower 66
Inside, the vapor and the liquid come into contact with each other, so that the solvent with a low boiling component collects toward the vapor and the water with a high boiling component collects more toward the liquid.

As a result, the solvent is sent to the condenser 72 through the exhaust pipe 70 as vaporized vapor, and is condensed by the condenser 72 to be collected in the collection tank 74 as a solution containing a high-concentration solvent. The water separated from the solvent is
The water is drained from the drain port 76 and sent to the storage tank 52 through a water pipe 82 having a water pump 86.

Here, a procedure for freezing and separating water containing a solvent in the refrigeration apparatus 22 to separate ice containing almost no solvent and water containing a high concentration of solvent will be described.

First, before supplying water containing a solvent from the intermediate tank 16 to the cooling pipe 36, the control unit 84 operates the electromagnetic switching valve 18, and fresh water is sent from the fresh water tank 90 to the cooling pipe 36. . This clean water contains almost no impurities (solvents, etc.), and is circulated through the cooling pipe 36, so that the cooling surface 36A has a height of 2.0 m as shown in FIG.
m or less of initial ice C1 is formed.

Since the initial ice C1 contains almost no solvent, it is possible to produce ice having a surface state free from irregularities and cracks. The unfrozen water remaining in the cooling pipe 36 is returned to the fresh water tank 90 through the circulation pipe 96 by the water supply pump 92. In addition, the solvent concentration of the fresh water is 500 pp
m or less can be used, and preferably 300 ppm or less.

Next, the electromagnetic switching valve 18 is switched, and the water containing the solvent is supplied from the intermediate tank 16 to the cooling pipe 36.
Water, and as shown in FIGS. 3 (B) and 3 (C),
An ice plate C2 is made on the surface of the initial ice C1. Here, the temperature of the water containing the solvent to be sent to the cooling pipe 36 is preferably 5 ° C. or lower, more preferably 3 ° C. or lower.

This is because if the temperature of the water containing the solvent is high, the surface of the initial ice C1 is melted to generate irregularities and cracks, and the ice plate C2 into which the solvent is taken may be iced. Because there is. As a means for controlling the temperature of the water containing the solvent, it is conceivable to attach a cooling coil to the intermediate tank 16.

As described above, the cooling surface on which the ice plate C2 is made is smoothed with the initial ice, so that ice containing almost no solvent is made as compared with the case where the surface has irregularities or cracks. As means for smoothing the cooling surface, coating the cooling surface 36A may be considered.

Next, in order to demonstrate the effect of the present invention, an ice making test was performed under different conditions as shown in the table of FIG. Note that the present invention is not limited to this test, and is included in the present invention without departing from the gist of the present invention.

From the exhaust gas containing methanol discharged from the plant P, methanol was collected by a scrubber as a gas-liquid contact device.

The exhaust gas containing methanol is 1.0 Nm
^It was introduced into the processing tower 12 at a rate of ³ / min. The content of methanol in the exhaust gas was 3000 ppm. The water pumped up from the treatment tank 14 was sprinkled from the sprinkler 32 of the treatment tower 12, and was subjected to batch treatment by introducing exhaust gas. The methanol concentration in the water discharged from the treatment tank 14 was 1000
It became 0 ppm.

The methanol concentration of this solvent is 1000
0 ppm of water was introduced into the freezing device 22 and subjected to freeze concentration treatment. At this time, the conditions of the thickness of the initial ice, the solvent concentration of the fresh water for forming the initial ice, and the temperature of the water containing the solvent to be introduced to the initial ice surface are changed to change the concentration of the solvent contained in the ice and the concentration of the unfrozen concentrate. The solvent concentration was measured and viewed.

As can be seen by comparing condition 5 and condition 6,
If the concentration of the solvent contained in the initial ice C1 is high, the concentration of the solvent in the whole ice produced becomes 405 ppm,
1 is larger than 270 ppm when no solvent is contained. However, the solvent concentration of the unfrozen concentrate is 29200
ppm and 29500 ppm, and there is no significant difference.

Further, as can be seen by comparing the conditions 1 to 3, the temperature of the water containing the solvent introduced to the surface of the initial ice C1 was changed to 23 ° C., 10 ° C., and 5 ° C. Due to the change in the surface state, the solvent content of the whole ice was 473 ppm, 434.5 ppm, 290 ppm.
ppm. However, the solvent concentration of the unfrozen concentrate was 29000 ppm, 29100 ppm, 29400 ppm.
ppm, there is not much difference.

As described above, after the ice-making plate is melted and returned to the treatment tank 14 to treat the exhaust gas, as shown in the table of FIG. Samples were taken to determine the removal rate of volatile organic compound (VOC) gas.

As a result, when the concentration of the solvent in ice was 100 p
pm, 300 ppm, 800 ppm, 2000 ppm, the removal rate of VOC gas was 93%, 90%, 85%
% And 70%, indicating that the solution can be reused as a processing solution absorbing VOC gas.

The concentration of the solvent component contained in the water sent to the freezing device 22 is preferably 1000 ppm, and more preferably 5000 ppm or more in order to concentrate the solvent to a high concentration.

Further, the water concentrated by the freezing device 22 may be reused as it is as an alternative fuel such as a washing liquid or heavy oil. When this concentrated water is sent to the still 64, the concentration of the solvent component contained in the water is preferably 1% or more, preferably 1% or more.
0% or more is more preferable.

Further, the cold water that has undergone heat exchange may be decomposed in a wastewater treatment facility using activated sludge or the like, and depending on the concentration of the contained solvent component (if the COD value and the BOD value are within the allowable values, ), It may be discharged as it is.

The type of the water scrubber, such as a spray type or a filling type, is not limited, and the type of absorbing gas into water may not be a scrubber. Further, the freezing device 22
The distiller 64 is used as a means for separating the water containing the solvent concentrated in the above into the solvent and the water, but a membrane separator, a centrifuge, or the like may be used.

Here, the production process of the PS plate, which is one of the production processes for generating VOC gas, will be briefly described.

The PS plate is a JIS containing 99.5% by weight of aluminum, 0.01% by weight of copper, 0.03% by weight of titanium, 0.3% by weight of iron, and 0.1% by weight of silicon.
-A1050 rolled sheet of aluminum material with a thickness of 0.30 mm was converted to a 400 mesh
Weight percent aqueous suspension and a rotating nylon brush (6,10-
(Nylon) and the surface was grained, and then washed well with water.

This was immersed in a 15% by weight aqueous solution of sodium hydroxide (containing 4.5% by weight of aluminum), etched so that the amount of aluminum dissolved was 5 g / m ² , and washed with running water. Furthermore, neutralize with 1% by weight nitric acid,
Next, in a 0.7% by weight nitric acid aqueous solution (containing 0.5% by weight of aluminum), a rectangular wave alternating waveform voltage (current ratio r = 0.9) having an anode voltage of 10.5 volts and a cathode voltage of 9.3 volts was used.
0, a current waveform described in Examples of JP-B-58-5796), and an electrolytic surface roughening treatment was carried out at an anode electricity amount of 160 coulomb / dm ² . After washing with water,
It was immersed in a 0% by weight aqueous sodium hydroxide solution, etched so that the amount of aluminum dissolved was 1 g / m ² , and washed with water. Next, it was immersed in a 50% by weight aqueous solution of 30% by weight sulfuric acid, desmutted, and washed with water.

Further, a porous anodic oxide film forming treatment was carried out in a 20% by weight aqueous sulfuric acid solution (containing 0.8% by weight of aluminum) at 35 ° C. using a direct current. That is, electrolysis was performed at a current density of 13 A / dm ² , and the anodic oxide film weight was adjusted to 2.7 g / m ² by adjusting the electrolysis time. To prepare a negative photosensitive lithographic printing plate using a diazo resin and a binder, the support was washed with water, immersed in a 3% by weight aqueous solution of sodium silicate at 70 ° C. for 30 seconds, washed with water and dried.

[0063] The thus-obtained aluminum support, reflection density was measured with Macbeth RD920 reflection densitometer 0.30, the center line average roughness R _a as defined in JIS B00601 is 0.58μm met Was.

Next, methyl methacrylate /
A 1.0% by weight aqueous solution of ethyl acrylate / 2-acrylamide-2-methylpropane sodium sulfonate copolymer (average molecular weight: about 60,000) (molar ratio: 50/30/20) was dried by a roll coater to obtain an applied amount of 1.0% by weight. 0.05g
/ M ² .

Further, the following photosensitive solution-1 was used as a coating solution.
Apply using the bar coater used in the present embodiment, 110 ° C
For 45 seconds. The dry coating amount was 2.0 g / m ² . Photosensitive solution-1 Diazo resin-1 0.50 g Binder-1 5.00 g Stylite HS-2 (manufactured by Daido Kogyo Co., Ltd.) 0.10 g Victoria Pure Blue BOH 0.15 g Tricresyl phosphate 0.50 g Dipicolinic acid 0 .20 g FC-430 (Surfactant manufactured by 3M) 0.05 g Solvent 1-methoxy-2-propanol 25.00 g Methyl lactate 12.00 g Methanol 30.00 g Methyl ethyl ketone 30.00 g Water 3.00 g The above diazo resin-1 Is obtained as follows. First, 29.4 g of 4-diazodiphenylamine sulfate (99.5% purity) was added at 25 ° C. to 96% sulfuric acid 70%.
ml and stirred for 20 minutes. to this,
3.26 g of paraformaldehyde (92% purity)
The mixture was gradually added over 0 minutes, and the mixture was stirred at 30 ° C. for 4 hours to allow the condensation reaction to proceed. The condensation molar ratio between the diazo compound and formaldehyde is 1: 1. The reaction product was poured into 2 liters of ice water with stirring, and treated with a cold concentrated aqueous solution in which 130 g of sodium chloride was dissolved. The precipitate is collected by suction filtration, the partially dried solid is dissolved in one liter of water, filtered, cooled on ice and washed with potassium hexafluorophosphate 23.
g was dissolved in an aqueous solution. Finally, the precipitate was collected by filtration and air-dried to obtain 1 g of diazo resin.

Binder-1 was 2-hydroxyethyl methacrylate / acrylonitrile / methyl methacrylate / methacrylic acid copolymer (weight ratio 50/20/26 /
4, average molecular weight 75,000, acid content 0.4 meq /
g) is a water-insoluble, alkaline water-soluble film-forming polymer.

Stylite HS-2 (manufactured by Daido Industry Co., Ltd.)
Is a polymer compound having a higher oil sensitivity than the binder,
It was a copolymer of styrene / mono-4-methyl-2-pentyl maleate = 50/50 (molar ratio), and the average molecular weight was about 100,000. A mat layer-forming resin solution was sprayed on the surface of the thus prepared photosensitive layer as described below to form a mat layer.

As a resin solution for forming a mat layer, methyl methacrylate / ethyl acrylate / 2-acrylamide-
2-methylpropanesulfonic acid (65: 2 weight ratio charged)
0:15) 12% of a part of the copolymer as a sodium salt
Prepare an aqueous solution and use a rotary atomizing electrostatic coating machine to atomize the head 2 times
5,000 rpm, the feeding amount of the resin liquid is 4.0 ml / min,
The voltage applied to the atomizing head was -90 kV, the ambient temperature during coating was 25 ° C, the relative humidity was 50%, and the coating surface was sprayed with steam for 2.5 seconds to wet the coating surface. Hot air with a temperature of 60 ° C. and a humidity of 10% was blown for 5 seconds to dry. The average height of the mat was about 6 μm, the average size was about 30 μm, and the application amount was 150 mg / m ² .

[0069]

Since the present invention has the above-described structure, the amount of replenishing water can be reduced, the solvent absorption efficiency can be maintained, and the solvent concentration of the treatment liquid finally discharged can be increased and reused. In addition, energy can be saved by using cold heat.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a gas-liquid contact device according to the present embodiment.

FIG. 2 is a block diagram showing a gas-liquid contact device according to the embodiment.

FIG. 3 is a schematic diagram showing a state in which an ice plate is made with ice.

FIG. 4 shows test results obtained by changing the solvent content of the initial ice and the temperature of the treated water introduced into the freezing apparatus, and obtaining the concentration of the solvent contained in the ice and the concentration of the solvent in the concentrated solution.

FIG. 5 is a table showing a recovery rate when a gas is recovered using recycled water.

FIG. 6 is a side view showing a conventional gas-liquid contact device.

[Explanation of symbols]

 Reference Signs List 12 processing tower 14 processing tank 22 freezing device (freezing means) 36 cooling pipe 36A cooling surface 42 circulation pump (freezing means) 56 ice storage tank (recycling means) 60 heat exchanger (recycling means, heat exchange means) 90 fresh water tank C1 Initial ice C2 ice plate

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 53/77 B01D 53/34 ZAB C02F 1/22 F-term (Reference) 4D002 AA40 AB03 AC10 BA02 BA13 CA01 CA07 DA35 EA02 EA08 EA14 FA01 GA01 GA02 GA03 GB02 GB05 GB08 GB11 GB20 HA08 4D020 AA08 BA23 BC01 BC10 CB25 CC10 CC12 DA02 DA03 DB06 DB20 4D037 AA15 AB11 BA21 4G075 AA03 AA37 AA45 BB02 BB04 BD13 CA02 CA03 CA01 EC02

Claims (5)

[Claims] A gas-liquid contact unit comprising: a processing tower into which gas is introduced from a gas generating source; a processing tank for supplying water to the processing tower and refluxing water having absorbed a solvent; A gas-liquid contact device comprising: a freezing unit that freezes water containing a solvent drained from the container; and a recycling unit that melts the ice frozen by the freezing unit and sends the water to the processing tank. A cooling surface of the freezing means on which the freezing water is frozen and adhered, is smoothed. 2. The air according to claim 1, wherein the means for smoothing the cooling surface includes sending clear water having a low solvent content to the freezing means, and forming initial ice on the surface of the cooling surface. Liquid contact device. 3. The solvent concentration in the fresh water is 500 p.
3. The gas-liquid contact device according to claim 2, wherein the pressure is not more than pm. 4. The temperature of water containing a solvent to be introduced into the freezing means, in which initial ice is formed on the surface of the cooling surface, is set at 5 ° C.
The gas-liquid contact device according to claim 2 or 3, wherein: 5. A freeze-concentration / separation method for freezing water containing a solvent with a freezing device to separate ice and a concentrated solution having a high solvent concentration, wherein an initial ice is formed on the cooling surface of the freezing device with fresh water. A freeze-concentration / separation method characterized in that water containing a solvent is made into ice on the surface of the initial ice to separate it into ice and a concentrate.