JP2016073940A - Concentration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concentration system for concentration treatment of a large amount of treatment target liquid with a simple system of a vacuum type membrane distillation unit and at a low cost.SOLUTION: A concentration system 1 for a treatment target liquid W has four branch lines 2A of a raw water line 2, which are provided respectively with vacuum type membrane distillation units 3 in parallel. These vacuum type membrane distillation units 3 have raw water chambers that introduce the treatment target liquid W and condensation chambers and makes a vacuum pump 4 as decompression degree measurement means communicate with the condensation chamber side and are provided with vacuum gauges 5 as decompression degree measurement means. Valves 6 for adjusting vacuum degrees are provided between the vacuum pump 4 and the vacuum type membrane distillation units 3 to be capable of controlling inflow amounts of the treatment target liquid W.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a concentration system for concentrating a large amount of liquid to be processed using a vacuum membrane distillation unit.

  Membrane distillation technology is expected to save energy and save space in applications that assume desalination from seawater, dehydration from solvents and oils, and other food processes such as fruit juice, sugar solution, and honey. . In particular, interest in vacuum membrane distillation units has increased in recent years.

  This vacuum membrane distillation unit has a flow path (raw water chamber) for passing a liquid to be treated at about 60 ° C. to 80 ° C. on one side through a hydrophobic porous membrane that repels water (permeates only water vapor). The water vapor that has passed through the hydrophobic membrane is led to the condensing part on the opposite side of the liquid to be treated and condensed to obtain distilled water as a unit structure, and this unit structure is arranged in multiple stages in series. Become. The concentrated liquid concentrated in the first stage of the unit structure is further concentrated in the second stage arranged in series, the processed liquid concentrated in the second stage is further concentrated in the third stage, and so on. It is concentrated one after another and collected after being concentrated in the final stage. On the other hand, the condensing chamber condenses the water vapor that has passed through the hydrophobic membrane to obtain distilled water, and is therefore at a temperature that is several degrees lower than the liquid to be treated. In this condensing chamber, the water vapor is condensed into distilled water, which is collected separately from the concentrated liquid. As the hydrophobic porous film, a Teflon (registered trademark) resin film having high water repellency is widely used. As this vacuum membrane distillation unit, techniques as disclosed in Patent Documents 1 and 2 are known.

JP 2011-173097 A JP 2013-212464 A

  Since the vacuum membrane distillation unit as described above is for evaporating and condensing a low-temperature liquid of several tens of degrees C. to less than 100.degree. C. under reduced pressure conditions, the degree of vacuum in the unit is distilled in addition to the liquid temperature. In order to influence the speed, the unit has a highly sealed structure and processing using a highly sealed material. A vacuum membrane distillation unit is not affected by osmotic pressure unlike a reverse osmosis membrane. In addition, by selecting the material of the unit, it can withstand high temperatures, acids and alkalis compared to reverse osmosis membranes, and it can be made lighter and less rusted by acids and alkalis than metal distillation cans. There are merits such as. For example, a hydrophobic porous membrane is made of Teflon (registered trademark) resin, and other units are made of polypropylene resin, Teflon (registered trademark) resin or vinylidene fluoride resin, and each member is welded and sealed. What is necessary is just to comprise a vacuum type film | membrane distillation unit by improving property.

  Because of the advantages as described above, a widely used vacuum membrane distillation unit is made of synthetic resin. However, since the strength of synthetic resin materials is weaker than that of metal materials, it is not easy to increase the size of a single unit in order to securely and reliably weld this synthetic resin material. There was a problem that it was not easy to concentrate the liquid. For this reason, a technique for increasing the amount of processing liquid by combining a plurality of units inexpensively and simply has been demanded.

  Therefore, as shown in FIG. 4, vacuum membrane distillation units are provided in parallel. In FIG. 4, the concentration system 31 of the liquid W to be treated has a branch line 32A in which the raw water line 32 is branched into a plurality (here, four), each of which has a vacuum membrane distillation unit 33 as a concentration means. A heat exchanger as a heating means (not shown) is arranged on the upstream side of the raw water line 32. These vacuum membrane distillation units 33 have a raw water chamber into which the liquid W to be treated and a condensation chamber are introduced, and the vacuum membrane distillation unit 33 has a decompression degree measuring means on the condensation chamber side. The vacuum pumps 34 are individually communicated with each other, and a vacuum gauge 35 is provided as a decompression degree measuring unit. The branch line 32A is provided with a valve 36 as a means for controlling the amount of inflow of the liquid W to be processed and a flow meter 37 for measuring the amount of inflow of the liquid W to be processed into the vacuum membrane distillation unit 33. ing.

  Thus, in the conventional concentration system provided with the vacuum membrane distillation unit 33 in parallel, the liquid W to be processed is heated to a predetermined temperature by a heat exchanger (not shown), and is, for example, less than 100 ° C., preferably 40 to 90 ° C. In particular, the temperature is adjusted to about 50 ° C. to 80 ° C., and then supplied to the vacuum membrane distillation unit 33 at the subsequent stage via the branch line 32A.

  At this time, the condensation chamber of the vacuum membrane distillation unit 33 is depressurized by the vacuum pump 34, and the vacuum state is monitored by the vacuum gauge 35 and maintained under reduced pressure, whereby the vapor of the liquid W to be treated is condensed into the condensation chamber. Be drawn into. As a result, the concentrate W1 is obtained in the raw water chamber, and is discharged and collected. At this time, in order to obtain a homogeneous concentrated solution W1 in each vacuum membrane distillation unit 33, the vacuum state of the vacuum membrane distillation unit 33 is monitored by a vacuum gauge 35, and the liquid to be treated to each vacuum membrane distillation unit 33 is monitored. The inflow amount of W is confirmed with the flow meter 37, and the opening condition of the valve 36 is adjusted to adjust the concentration condition.

  Thus, conventionally, in order to make the concentrate W1 obtained from each vacuum membrane distillation unit 33 substantially homogeneous, the flow meter 37 and the valve 36 are combined to provide a vacuum membrane distillation unit for the liquid W to be processed. The supply amount to 33 is adjusted. However, in the food process, for example, the conductivity of the liquid W to be processed is extremely low, the viscosity of the liquid W to be processed is extremely high, or a lot of fine suspensions are included. In many cases, an electromagnetic flow meter and an area type flow meter that are inexpensive and less contaminated cannot be applied, and the supply amount of the liquid W to be processed to each vacuum membrane distillation unit 33 cannot be measured easily. For this reason, it is necessary to manually measure the amount of concentrated liquid, the amount of distilled water, and the amount of demister, or to apply an expensive and low flow meter such as a Coriolis flow meter, and the flow measurement is complicated. There was a problem that mass measurement was not easy.

  Furthermore, in the conventional system described above, when the vacuum membrane distillation units 33 are arranged in parallel, the same number of expensive flow meters as the units 33 are required, which is accompanied by a significant increase in cost, and is not suitable for mass processing. Met.

  The present invention has been made in view of the above problems, and provides a simple system and a concentration system for concentrating a large amount of liquid to be processed at a low cost using a vacuum membrane distillation unit. To do.

  In order to solve the above problems, the present invention is a concentration system comprising two or more stages of vacuum membrane distillation units for concentrating a liquid to be treated, wherein the vacuum membrane distillation unit comprises a hydrophobic porous membrane. Partitioned raw water section and condensing section, depressurizing means for maintaining the condensing section in a depressurized state, depressurization degree measuring means for measuring the depressurizing state of the condensing section, and the liquid to be processed to the vacuum membrane distillation unit Control means for controlling the inflow amount, the decompression means is provided in common to the parallel vacuum membrane distillation unit, the control means based on the measurement value of the decompression degree measurement means, Provided is a concentration system characterized in that the degree of decompression by the decompression means or the inflow amount of the liquid to be treated into the raw water part can be adjusted (Invention 1).

  According to this invention (Invention 1), the degree of vacuum of the vacuum membrane distillation unit measured by the degree of vacuum measuring means is adjusted, or the degree of pressure reduction by the pressure reducing means or the amount of inflow of the liquid to be treated into the raw water section is adjusted. Thus, a homogeneous concentrate can be obtained from each vacuum membrane distillation unit. This is because in a vacuum membrane distillation unit, the vacuum membrane distillation unit is depressurized and the liquid to be treated is sucked into the vacuum membrane distillation unit due to the increased vacuum, so the vacuum membrane distillation unit The supply amount of the liquid to be processed is proportional to the degree of vacuum in the unit. By utilizing this property, the supply amount of the liquid to be processed can be adjusted without using an expensive flow meter. Thus, the vacuum membrane distillation unit can be suitably applied to process a large amount of liquid to be processed.

  In the said invention (invention 1), it is preferable that the said control means is connected with the said pressure reduction means, and the pressure reduction degree by the said pressure reduction means can be adjusted (invention 2).

  According to this invention (Invention 2), based on the vacuum degree of each vacuum membrane distillation unit measured by the vacuum degree measuring means, the vacuum degree by the vacuum means is adjusted by the control means communicating with the vacuum means, and each vacuum It is possible to obtain a uniform concentrated solution from each vacuum membrane distillation unit by making the degree of vacuum of the membrane distillation unit uniform and uniformly controlling the supply amount of the liquid to be treated. As a result, the supply amount of the liquid to be processed can be adjusted without using an expensive flow meter. Thus, the vacuum membrane distillation unit can be suitably applied to process a large amount of liquid to be processed.

  Moreover, in the said invention (invention 1), the said control means is provided in the introduction side of the raw | natural water part of the said vacuum-type membrane distillation unit, and it becomes possible to adjust the inflow amount of the to-be-processed liquid to the said raw | natural water part. (Invention 3)

  According to this invention (invention 3), based on the degree of vacuum of each vacuum membrane distillation unit measured by the degree of reduced pressure measurement means, the control means provided on the introduction side of the raw water section allows the liquid to be treated to the raw water section. By adjusting the inflow amount, the supply amount of the liquid to be treated can be controlled according to the degree of vacuum of each vacuum membrane distillation unit, and a homogeneous concentrated liquid can be obtained from each vacuum membrane distillation unit. As a result, the supply amount of the liquid to be processed can be adjusted without using an expensive flow meter. Thus, the vacuum membrane distillation unit can be suitably applied to process a large amount of liquid to be processed.

  Furthermore, in the said invention (invention 1-3), it is preferable to provide the heating means which heats the said to-be-processed liquid introduce | transduced into the said raw | natural water part of the said vacuum membrane distillation unit using waste heat (invention 4). .

  According to this invention (invention 4), it is possible to effectively use heat energy by utilizing waste heat as a heat source of the heating means, and further energy saving and cost saving can be achieved. It is also effective for industrial revitalization.

  The concentration system of the present invention adjusts the degree of decompression by the decompression means or the amount of inflow into the raw water section based on the degree of vacuum of each vacuum membrane distillation unit measured by the degree of decompression measurement means, thereby By controlling the supply amount of the liquid to be treated according to the degree of vacuum, a homogeneous concentrated liquid can be obtained from each vacuum membrane distillation unit. As a result, the supply amount of the liquid to be processed can be adjusted without using an expensive flow meter. This enables vacuum membrane distillation in industrial applications that require large-scale processing such as seawater desalination, dehydration from solvents and oils, and food processes such as concentration of fruit juice, sugar solution, and honey. The unit can be suitably applied.

It is the schematic which shows the concentration system which concerns on 1st embodiment of this invention. It is the schematic which shows an example of a vacuum type film | membrane distillation unit. It is the schematic which shows the concentration system which concerns on 2nd embodiment of this invention. It is the schematic which shows the conventional concentration system.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing a concentration system according to a first embodiment of the present invention. In FIG. 1, the concentration system 1 of the liquid W to be processed has branch lines 2A in which the raw water line 2 branches into a plurality (four in the present embodiment), each of which is a vacuum membrane distillation as a concentration means. The units 3 are provided in parallel, and a heat exchanger as heating means (not shown) is arranged on the upstream side of the raw water line 2. These vacuum membrane distillation units 3 have a raw water chamber for introducing the liquid W to be treated and a condensing chamber. A vacuum pump 4 as a depressurizing means communicates with the condensing chamber side. A vacuum gauge 5 is provided as a measuring means. A valve 6 is provided between the vacuum pump 4 and the vacuum membrane distillation unit 3 as a control means for adjusting the degree of vacuum by the vacuum pump 4 to control the inflow amount of the liquid W to be processed. It is possible.

  FIG. 2 shows an example of the vacuum membrane distillation unit 3. The vacuum membrane distillation unit 3 uses a low temperature waste heat to pass a liquid W to be treated heated by a heat exchanger (not shown) through a hydrophobic porous membrane, and distills the vapor under reduced pressure and low temperature conditions. Or use a membrane distillation technique to concentrate.

  The vacuum membrane distillation unit 3 includes a hydrophobic porous membrane 11, and a raw water chamber 12 and a condensing chamber 13 are formed by being partitioned by the hydrophobic porous membrane 11. The raw water chamber 12 is an example of a raw water unit that introduces the liquid W to be treated, and the condensing chamber 13 is an example of a condensing unit that condenses the vapor S that has passed through the hydrophobic porous membrane 11.

  The hydrophobic porous membrane 11 is an example of means for selectively allowing only the vapor of the liquid W to be treated introduced into the raw water chamber 12 to pass through. As the hydrophobic porous membrane 11, a fluororesin porous membrane can be suitably used because of its excellent heat resistance. In this hydrophobic porous membrane 11, only the vapor S of the liquid to be treated W is permeated, hardly affected by the osmotic pressure and viscosity of the liquid W to be treated with respect to the amount of vapor passing through the membrane, has high vapor permeability, and is treated. Concentration of the suspended component of the liquid W can be performed efficiently.

  A vacuum pump 14 (the vacuum pump 4 in FIG. 1) is connected to the condensation chamber 13, and a cooling unit 15 is provided on the wall surface of the condensation chamber 13. The raw water chamber 12 is decompressed by the vacuum pump 14 together with the condensing chamber 13 and maintained in a depressurized state, and the cooling unit 15 is cooled by a cooling means (not shown) to a temperature at which the steam S in contact therewith is condensed.

  In addition, as the to-be-processed liquid W used as the said concentration object, the food related solution containing sugars, such as fruit juice, liquid sugar, and honey, is suitable. Here, in the liquid W to be treated, the initial concentration of the target concentrated component such as sugar is 10% or less, particularly about 2 to 7%. It can also be suitably applied to process discharge in industrial processes such as seawater desalination and dehydration from solvents and oils.

  Next, the operation of the concentration system 1 of the present embodiment including the four vacuum membrane distillation units 3 as described above in parallel will be described.

  First, the temperature of the liquid W to be treated is adjusted to a predetermined temperature, for example, less than 100 ° C., preferably 40 to 90 ° C., particularly about 50 ° C. to 80 ° C. by a heat exchanger (not shown), and then passes through the branch line 2A. It is supplied to the vacuum membrane distillation unit 3 at the subsequent stage. Here, each vacuum membrane distillation unit 3 is decompressed by a single vacuum pump 4. Therefore, the liquid W to be treated is sucked into the raw water chamber 12 of the vacuum membrane distillation unit 3 if the valve 6 is open.

  In this case, since the condensing chamber 13 is maintained in a reduced pressure state, it has not only a function of drawing the steam S but also a function of lowering the boiling point of the liquid W to be processed. Thereby, the vapor | steam S which arises from the to-be-processed liquid W becomes remarkable, and the vapor | steam amount which permeate | transmits the hydrophobic porous membrane 11 increases. As a result, the concentrate W1 is obtained in the raw water chamber 12. That is, since much steam S is condensed and removed from the liquid W to be processed and converted into the concentrated liquid W1, the liquid W to be processed in the raw water chamber 12 is efficiently concentrated. Accordingly, a large amount of concentrated liquid W1 is generated from the raw water chamber 12 and recovered from the concentrated liquid recovery line 16. On the other hand, the vapor S touches the cooling unit 15 of the condensation chamber 13 and condenses, and water droplets L are generated. Thereby, the steam S is condensed in the cooling unit 15, and the distilled water W <b> 2 is discharged from the distilled water discharge line 17.

  In such membrane distillation, when the liquid W to be processed is concentrated to obtain the concentrated liquid W1, the channel width and the membrane surface line flow rate of the liquid W to be processed are important. The channel width is a size such as a channel diameter effective for passing the liquid W to be processed. On the other hand, the film surface linear velocity is a linear velocity given by a value obtained by dividing the flow rate of the liquid W to be processed by the effective cross-sectional area in the apparatus, and is apparently the velocity of the liquid W to be processed. Specifically, the average flow velocity of the liquid W to be processed is parallel to the membrane surface of the hydrophobic porous membrane 11.

  In the vacuum membrane distillation unit 3, the flow path width w of the liquid W to be processed may be, for example, 1 [mm] or more and 30 [mm] or less, and more preferably 3 [mm] or more and 20 [ mm] or less. Further, the membrane surface flow velocity V of the liquid W to be treated is, for example, 0.01 [m / s] or more and 5 [m / s] or less, more preferably 0.05 [m / s] or more and 2 [m]. / S] or less.

  Here, it is preferable that the four vacuum membrane distillation units 3 have the same conditions. Therefore, the height position of each vacuum membrane distillation unit 3 and the suction port height of the liquid W to be processed are preferably the same.

  The inflow amount of the liquid W to be treated into the raw water chamber 12 is usually determined by the degree of vacuum of the vacuum membrane distillation unit 3. The amount of the liquid W to be treated flowing into the raw water chamber 12 can be increased or decreased by adjusting the degree of vacuum of the vacuum membrane distillation unit 3, that is, by adjusting the opening of the valve 6. The exhaust capacity of the vacuum pump 4 may be determined according to the volume and the number of vacuum membrane distillation units 3.

  Specifically, in this embodiment, each vacuum membrane distillation unit 3 is depressurized by a common vacuum pump 4, so the vacuum degree of each vacuum membrane distillation unit 3 and the object to be treated are reduced. If the flow path length of the liquid W is the same and the vacuum membrane distillation unit 3 has the same conditions, the suction force of the liquid W to be treated between the vacuum membrane distillation units 3 is basically the same. The same amount of the liquid W to be treated flows into the vacuum membrane distillation unit 3 and is concentrated by distillation, whereby a concentrated liquid W1 and distilled water W2 having the same concentration can be obtained.

  On the other hand, when the length of the branch line 2A of the liquid W to be processed is different for each vacuum membrane distillation unit 3, the vacuum gauge is considered in consideration of the difference in flow path resistance caused by the length of the flow path 2A of the liquid W to be processed. The opening degree of the valve 6 of each vacuum membrane distillation unit 3 is adjusted so that the measured value of 5 is different. Needless to say, the difference in the pressure difference caused by the difference in the pipe diameter of the branch line 2 </ b> A of each vacuum membrane distillation unit 3 is considered in the difference in the degree of vacuum of each vacuum membrane distillation unit 3.

  The relationship between the amount of inflow of the liquid W to be processed and the degree of vacuum of the unit 3 into the plurality of (four) vacuum membrane distillation units 3 controlled as described above is the property of the liquid W to be processed. In particular, since it depends on temperature and viscosity, it is confirmed beforehand by experiment. By adjusting the valve 6 so that the degree of vacuum of the vacuum membrane distillation units 3 connected in parallel in this way is constant, the same amount of liquid W to be treated flows into each unit 3 and is concentrated by distillation. Thus, the concentrated solution W1 having the same concentration can be obtained from each vacuum membrane distillation unit 3. And the density | concentration of this concentrate W1 can also be controlled to some extent.

  In this vacuum membrane distillation unit 3, the concentration of the liquid W to be processed depends on the property and temperature of the liquid W to be processed, but it is a high concentration of about 70 to 80% (volume reduction rate, the same applies hereinafter). To about 40-70%. Therefore, depending on the target concentration rate, the vacuum membrane distillation unit 3 can be further concentrated in series as necessary in multiple stages, for example, 2 to 12 stages, preferably 3 to 10 stages.

  Next, a concentration system according to a second embodiment of the present invention will be described. FIG. 3 is a schematic view showing a concentration system according to the second embodiment. In FIG. 3, the concentration system 21 of the liquid W to be treated has branch lines 22A in which the raw water lines 22 are branched into a plurality (four in this embodiment), each of which is a vacuum membrane distillation as a concentration means. Units 23 are provided in parallel, and a heat exchanger as a heating means (not shown) is arranged upstream of the raw water line 22. These vacuum membrane distillation units 23 have a raw water chamber for introducing the liquid W to be treated and a condensing chamber. A vacuum pump 24 as a depressurizing means communicates with the condensing chamber side, and the degree of decompression is measured. A vacuum gauge 25 is provided as a means. And the valve | bulb 26 as a control means of the inflow amount of the to-be-processed liquid W is each provided in the introduction side of the raw | natural water chamber 12 of the vacuum membrane distillation unit 23 of each branch line 22A. As the vacuum membrane distillation unit 23, the one shown in FIG. 2 can be used as in the first embodiment described above.

  Next, the operation of the concentration system 1 of the second embodiment including the four vacuum membrane distillation units 23 as described above in parallel will be described.

  First, the temperature of the liquid W to be treated is adjusted to a predetermined temperature, for example, less than 100 ° C., preferably about 40 to 90 ° C., particularly about 50 ° C. to 80 ° C. by a heat exchanger (not shown), and then passes through the branch line 22A. It is supplied to the vacuum membrane distillation unit 23 in the subsequent stage. Here, the vacuum membrane distillation unit 23 is depressurized by a single vacuum pump 24. Therefore, the liquid W to be treated is sucked into the raw water chamber 12 of the vacuum membrane distillation unit 23 if the valve 26 is opened. The liquid W to be treated in the raw water chamber 12 is efficiently concentrated to produce a concentrated liquid W1, which is recovered from the concentrated liquid recovery line 16. On the other hand, the vapor S touches the cooling unit 15 of the condensation chamber 13 and condenses, and water droplets L are generated. As a result, the steam S is condensed in the cooling unit 15, and distilled water W <b> 2 is discharged from the distilled water discharge line 17.

  Here, it is preferable that the four vacuum membrane distillation units 23 have the same conditions. Therefore, it is preferable that the height position of each vacuum membrane distillation unit 23 and the suction port height of the liquid W to be processed are the same.

  The inflow amount of the liquid W to be treated into the raw water chamber 12 is usually determined by the degree of vacuum of the vacuum membrane distillation unit 23. Therefore, the amount of the liquid W to be treated flowing into the raw water chamber 12 is increased or decreased by adjusting the opening of the valve 26 in accordance with the degree of vacuum of the vacuum membrane distillation unit 23. The exhaust capacity of the vacuum pump 24 may be determined according to the volume and number of vacuum membrane distillation units 23.

  Specifically, in this embodiment, each vacuum membrane distillation unit 3 is depressurized by a common vacuum pump 4, so the vacuum degree of each vacuum membrane distillation unit 23 and the processing target are reduced. If the flow path length of the liquid W is the same and the vacuum membrane distillation unit 23 has the same conditions, the suction force of the liquid W to be treated between the vacuum membrane distillation units 23 is basically the same. The same amount of the liquid W to be treated flows into the vacuum membrane distillation unit 23 and is concentrated by distillation, whereby a concentrated liquid W1 and distilled water W2 having the same concentration can be obtained.

  On the other hand, when the length of the branch line 22A of the liquid W to be processed is different for each vacuum membrane distillation unit 23, the vacuum gauge is considered in consideration of the difference in flow path resistance caused by the length of the branch line 22A of the liquid W to be processed. The opening degree of the valve 26 of the branch line 22A is adjusted so that the 25 measured values are different. That is, when the degree of vacuum is high, the opening degree of the valve 26 is increased so that the inflow amount of the liquid W to be processed increases, and when the degree of vacuum is low, the opening degree is decreased so that the inflow amount of the liquid W to be processed decreases. Needless to say, the difference in the pressure difference caused by the difference in the diameter of the branch line 22 </ b> A of each vacuum membrane distillation unit 23 is taken into account in the difference in the degree of vacuum of each vacuum membrane distillation unit 23.

  The relationship between the amount of inflow of the liquid W to be processed and the degree of vacuum of the units 23 into a plurality of (four) vacuum membrane distillation units 23 controlled as described above is the property of the liquid W to be processed. In particular, since it depends on temperature and viscosity, it is confirmed beforehand by experiment. By adjusting the inflow amount of the liquid W to be processed in accordance with the degree of vacuum of the vacuum membrane distillation units 23 connected in parallel in this way, the liquid to be processed corresponding to the degree of vacuum in each unit 23 is adjusted. As W flows in and is concentrated by distillation, concentrated liquid W1 having the same concentration can be obtained from each vacuum membrane distillation unit 3. And the density | concentration of this concentrate W1 can also be controlled to some extent.

  Like this embodiment, you may adjust by providing the valve | bulb 26 in the inflow side (introduction side of the raw | natural water chamber 12) of the to-be-processed liquid W, and adjusting the inflow amount according to a vacuum degree.

  Although the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made. The degree of opening and closing of the valves 6 and 26 as the control means in the first embodiment and the second embodiment may be automatically adjusted according to the degree of vacuum of the vacuum membrane distillation unit 23 using an automatic valve. Good.

  In addition, the distilled water W2 can be used for water, for example, a reverse osmosis membrane, the washing water of a membrane distillation unit, or dilution water as needed, and can use resources effectively.

  According to the concentration system of the present invention, it is possible to obtain a homogeneous concentrate from each vacuum membrane distillation unit by controlling the supply amount of the liquid to be treated according to the degree of vacuum of the plurality of vacuum membrane distillation units. As a result, in addition to seawater desalination, dehydration from solvents and oils, etc., food processing, such as vacuum for industrial applications where large-scale treated water needs to be processed, such as concentration of fruit juice, sugar solution, honey, etc. The applicability of the formula membrane distillation unit can be enhanced.

1, 21 ... Concentration system 2, 22 ... Raw water line 2A, 22A ... Branch line 3, 23 ... Vacuum membrane distillation unit 4, 24 ... Vacuum pump (pressure reduction means)
5, 25 ... Vacuum gauge (pressure reduction measuring means)
6, 26 ... Valve (control means)
DESCRIPTION OF SYMBOLS 11 ... Hydrophobic porous membrane 12 ... Raw water chamber 13 ... Condensing chamber 14 ... Vacuum pump 15 ... Cooling part W ... Liquid W1 ... Concentrated liquid W2 ... Distilled water S ... Steam

Claims (4)

A concentration system comprising two or more stages of vacuum membrane distillation units for concentrating a liquid to be treated,
The vacuum membrane distillation unit is
Raw water section and condensation section partitioned by a hydrophobic porous membrane;
Pressure reducing means for maintaining the condensing part in a reduced pressure state;
Decompression degree measuring means for measuring the depressurized state of the condensing part,
Control means for controlling the flow rate of the liquid to be treated into the vacuum membrane distillation unit,
The decompression means is shared by the parallel vacuum membrane distillation units,
The concentration system characterized in that the control means can adjust the degree of pressure reduction by the pressure reduction means or the inflow amount of the liquid to be treated into the raw water part based on the measurement value of the pressure reduction degree measurement means.   The concentration system according to claim 1, wherein the control unit communicates with the decompression unit, and the degree of decompression by the decompression unit can be adjusted.   The said control means is provided in the introduction side of the raw | natural water part of the said vacuum-type membrane distillation unit, The inflow amount of the to-be-processed liquid to the said raw | natural water part can be adjusted. Concentration system.   The concentration system according to any one of claims 1 to 3, further comprising heating means for heating the liquid to be treated introduced into the raw water portion of the vacuum membrane distillation unit using waste heat.

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