JP3527263B2 - How to operate the cooling tower - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention relates to a method for operating a cooling water tower,
For more information, SupplementCooling tower operation method that can reduce water supply
Related. [0002] 2. Description of the Related Art A cooling water tower is used to keep water below its temperature.temperature
ofContact with airTouchAnd evaporate a part of it into the air and evaporate
By releasing latent heatThe waterLet it coolYes,Large amounts of
Various factories, plants, building air conditioning equipment that requires cooling water
Etc. are widely used. [0003] Regarding the cooling water tower, regardless of the method,
Water is circulated and used for cooling.
Constant for evaporation phenomena according to temperature, humidity, etc.
A quantity of water is lost as evaporating water. As a result, in the circulating water
It causes an increase in the salt concentration of the contained Na salt, Ca salt, K salt, etc.
If left unchecked, pumps, pipes and heat
It is not preferable because it causes corrosion of devices such as exchangers.ButWhat
The salt concentration in the circulating water must always be kept below a specified value.
Yes, so a predetermined amount of water is circulated as blowdown water
Removed from water and circulates water with low salt concentration as makeup water
The water needed to be replenished. [0004] [Problems to be solved by the invention]recent years,Low salt concentration
Obtaining pure water becomes increasingly difficultCageIn the cold water tower
SupplementReduction of water supply is strongly desired. [0005] The present invention solves the above problems.
This is done in order to determine
Circulate make-up water corresponding to the amount of lowdown water and evaporating water.
In an operation method of a cooling water tower that cools while supplying to the ring water,
Using a monovalent anion selective permeable membrane as the anion exchange membrane
WasIn the dilution room of the electrodialysis tankBlowdown water or makeup water
ToSupply and energize,From blowdown water or makeup water
The monovalent anion is selectively removed and obtained from the dilution chamber.
Circulating blowdown water or makeup water with reduced salt concentration
Supply toIt is characterized by doing. [0006]BookThe cooling tower operated by the invention is natural or strong.
Any of the ventilation towers may be used.
Countercurrent type or cross-flow type may be used.
Is also applicable. The cooling water obtained in these cooling water towers is
StatementEquipmentetcThe water that is used in
After being returned to the cooling water tower and cooled again, it is recycled. Or
The circulating water flows there due to the evaporation of water in the cooling tower.
NaCl and CaCO contained in_Three, MgCO_Three, Na_TwoS
O_FourThe concentration of salt such as
Preferably 2000 ppm or less, especially 1000 ppm or less.
Need to control down. If the above concentration is exceeded,
This is because a problem such as corrosion of the device occurs. To control the salt concentration in the circulating water, the salt concentration
Part of the circulating water that has risen out of the system as blowdown water
As well as lost due to evaporation and blowdown.
Low make-up water with low salt concentration
New water is supplied to the circulating water. Thus, the broker
CWaterWhen the amount is large, the amount of makeup water increases. [0008] In the present invention,WaterTo reduce the volume
To,Lowdown waterOr make-up waterIs electrodialyzed. Electrical
In dialysis,Lowdown waterOr make-up waterIs a rare electrodialysis tank
It is supplied to the chamber and is energized. Of the above,
water supplyTheElectrodialysis of blowdown water in case of hemodialysis
Cell voltage rises as dialysis progresses as if
The present invention can be implemented more efficiently.
Wear. The electrodialysis tank used in the present invention is a
Exchange membrane and anion exchange membrane(Preferably monovalent anion selection
Selective anion exchange membrane)And multiple arrays between electrodes
Electrodialysis tank in which a dilution chamber and a concentration chamber are alternately formed
It is. As a cation exchange membrane,Fluoric acid group
On-exchange groupIs preferred,Ion exchange volumeThe quantity is
0.5-10 meq / g dry resinPreferably
K,thicknessIs50-500 μmIs preferably. Sun
Ion exchange membranes can be either homogeneous or heterogeneous
Can be used, but homogeneousDesuTylene-divinylben
It is preferable to use a membrane having a zen copolymer as a base. Positivity
Exchange membranes can be polyolefin, polyvinyl chloride
Reinforced with woven or non-woven fabric such as
Can be used. [0010] The anion exchange membrane is preferably
Anion having a secondary ammonium group as an anion exchange group
Exchange membrane is usedYou.Monovalent anion selectionSex anion
The exchange membrane isMonovalent anions such as chloride ion and nitrate ion
Is more selective than polyvalent anions such as sulfate ions.
Has the property of passingAnd preferablyused. In this case
Monovalent anion / multivalentshadowIon selectivityIs 2More than twice, especially
Is more than 5 timespreferable.Anion exchange membraneIon exchange volume
amountIs 0. 5-10 meq / g dry resinGood to be
Magusuku,thicknessIs50-500 μmPreferably
I. Anion exchange membrane is uniformFamilyIs any of heterogeneousof
thingCan be used.
Use of membranes based on lubenzene copolymerIs preferred. ElectrodialysisTank, Cation exchange membranes and anions
Exchange membrane andTo10 to 600 sheets are alternately arranged between the electrodes.
Line up to form dilution and concentration chambersPreferably.
Means for assembling the electrodialysis tank is disclosed in
JP-A-55-24538 and JP-B-51-47663.
Any of the known listed may be used. In the present invention,
Of these, a clamping type (filter press type) device is preferably used
Is done. In the present invention,Lowdown waterOr supply
waterIs the dilution chamber of the above electrodialysis tankTo5-50cm / se
supplied by cPreferably. ElectrodialysisTankConcentration room
When the operation of the electrodialysis tank is started,
Ions and anions migrate as water moves
Supply of aqueous electrolyte solutionMustNot necessary,coldBu from the water tower
Lowdown water is supplied at 0.5-5cm / sec
Preferably. The blowdown water contains various
ContaminationYouIn many cases, the
Deposited on the exchange membraneThere is a risk. For this reasonElectrodialysis tank
On supply to, Suspended matter concentration is less than 1 ppm
It is preferable to filter. At both ends of the electrodialysis tank, an anode and a cathode
Is containedLuyangIn the pole room and cathode room,Aqueous solution, example
For example, the same aqueous electrolyte solution supplied to the above-mentioned concentration chamber
Supplied. [0014]ElectricIn the dialysis tank, a low
Preferably 0.1 to 10 A / dm^TwoWith a current density of
Supplied to the dilution chamberTabLowdown waterOr make-up water
During ~SunshineIons and anions are converted to cation exchange membrane and
And transfer to the concentration chamber through anion exchange membrane
Desalted. Monovalent anion selection as anion exchange membrane
sexAnion exchangeIf a membrane is used, SO_Four ^2-Such as
Compared to divalent or higher polyvalent anionsColdIn water towers, etc.
Corrosion of equipmentEasy to do Cl ^- , NO _Three ^- Etc.Monovalent shade
Especially, since ON is almost selectively transferred to the concentration chamber and removed.
preferable. In such cases, the allowable salt concentration in the circulating waterTo
Blow down water as it can be largeThrough And discharge outside the system
WaterMore effective in reducing water consumption and, consequently, make-up water.
is there. [0015]BookAccording to the invention, by electrodialysis,Low
Down waterOr make-up waterThe salt concentration in is preferably 1000
Desalted to ~ 2000ppm, especially 200 ~ 500ppm
Be done. ProfitWater with reduced salt concentration is supplied to the cooling tower
With waterCirculating waterIs added during. On the other hand, the concentration of electrodialysis
Water with an increased salt concentration is obtained from the constriction chamber.Is the systemOutside
ToEmissionIs done. [0016] In the present invention,,Lowdown waterOr make-up waterThe electricity
Dialysis reduces salt concentration in these waters
Recruited and eventually replenishedWater volumeIs reduced. The mechanism
Is as follows. When electrodialysis is performed on the makeup water, supply the circulating water.
Salt concentration in supplied waterToTo be able to reduce
Even if water evaporates, the rise of salt concentration in circulating water can be controlled
Come on, resulting in blowdown waterIs discharged out of the system through
WaterThe amountFewCan, Reducing the amount of makeup waterYou. On the other hand, when blowdown water is electrodialyzed
Can regenerate blowdown water as water with low salt concentration
And re-use this as make-up water,
Reduce the amountWear. [0019] Embodiment 1 CirculationWater is5000m^Three/ Day, evaporationWater is800m^Three/ Day, bu
Lowdown water (TDS 1000ppm, Na⁺150p
pm, Ca⁺⁺70 ppm, Cl^-250 ppm) is 20
0m^Three/ Day, make-up water (TDS 200ppm, Na⁺30p
pm, Ca⁺⁺14 ppm, Cl^-50 ppm) is 100
0m^Three/ Day of the cooling tower.Here, TDS is all
Shows the amount of dissolved solids (hereinafter, also referred to as TDS). The blowdown water of the cooling water tower is
Dialyzed. The following was used as the electrodialysis tank. Strong acid
Cation exchange membraneIs"Seremion CMV" (Asahi Glass
Styrene-divinylbenzene having a sulfonic acid group
Copolymer membrane, ion exchange capacity 3.4 meq / g dry
Resin, thickness 150μm) and strong basic anion exchange membraneIn
To"Seremion AMV" (Asahi Glass Co., Ltd., Quaternary Ammonium
Styrene-divinylbenzene copolymer film having a rubber group,
Ion exchange capacity 3.4 meq / g dry resin, thickness 14
0 μm) and 30 eachEach,cathode・Polypropylene between anodes
Filters arranged and assembled alternately via len spacers
-Press type electrodialysis tank Selemion DB-4 (Asahi Glass Co., Ltd.)
Made, effective membrane area 0.8m^Two)It was used. In the dilution chamber of the electrodialysis tank, the blow
Down water is supplied by the circulation pump through the diluent tank
The concentrate chamber, the cathode chamber and the anode chamber also
And the same pump as above with a circulation pump through the anolyte tank.
Circulate the lowdown water and reduce the voltage from the DC power supply to about 50
V was applied, current was supplied at a current of 80 A, and the operation was continued. When the operation is stabilized after a while,
Dilution liquid flowing out of the diluent tank and concentrate tank
And the concentrate were as follows. That is, the dilution liquid,TD
S200ppm, Na⁺30 ppm, Ca⁺⁺14pp
m, Cl^-50 ppmIs, Concentrate is TDS180
0 ppm, Na⁺270 ppm, Ca⁺⁺126 ppm,
Cl^-450 ppmIs, Liquid volume is 100m^Three/
Was the day. UpDiluent for electrodialysis tankComplementIn addition to water supply
It was supplied to the circulating water of the cooling water tower. This results in blowdown water
Out of, Concentration of the above electrodialysis tankLiquid 100m^Three/DayIs outside the system
Is discharged to, Make up water 100m^Three/DayonlySaving 9
00m^Three/ Day. Embodiment 2 In Example 1, the blowdown waterThe electrodialysis tank dilution
Supply to the room900m of make-up water instead^Three/ Electric transparent
It was supplied to the dilution chamber of the precipitation tank and electrodialyzed in the same manner..
SetThe analysis was performed when normal operation was reached.
From the dilution chamber, TDS 588 ppm, Na⁺9pp
m, Ca⁺⁺4.2 ppm, Cl^-14.7ppm dilution
Liquid is 850m^Three/DayGet inTDS2
600 ppm, Na⁺390 ppm, Ca⁺⁺182pp
m, Cl^-650ppm concentrated solution is 50m^Three/DaysoObtained
Was. The above-mentioned diluted solution was completely cooled as make-up water for a cooling water tower.
After driving to the water tower,Cold water towerAre, TDS
1000 ppm, Na⁺150 ppm, Ca⁺⁺70pp
m, Cl^-250 ppmBlowdown water50m^Three/Day
Obtained byWas. Embodiment 3 In Example 2, a normal anion was used as the anion exchange membrane.
Monovalent anion-selective anion exchange membrane instead of ion exchange membrane
"Seremion ASV" (Asahi Glass Co., Ltd., quaternary ammonium
Group-containing styrene-divinylbenzene copolymer,
Exchange capacity 3.4 meq / g dry resin, thickness 140μ
m) using an electrodialysis tank and supplying it to the dilution chamber
Supply water860m³/ Day, except that
For electrodialysis. As a result, from the dilution chamber of the electrodialysis tank, T
DS 43 ppm, Na⁺11 ppm, Ca⁺⁺7 ppm,
Cl^-830m of the diluted solution of 3.6ppm^Three/DaysoObtained
From the concentration chamber, TDS4543 ppm, Na⁺548p
pm, Ca⁺⁺203 ppm, Cl^-1333 ppm concentration
30m^Three/DaysoObtained. The above-mentioned diluted solution was completely cooled as make-up water for a cooling water tower.
When the water tower was supplied and operated,Are, TDS
1200 ppm, Na⁺304 ppm, Ca⁺⁺193p
pm, Cl^-100 ppmBlowdown water30m^Three/
DayObtained byWas. Embodiment 4 In Example 3, whether the enrichment chamber of the electrodialysis tank was initially energized
Water (TDS800p) discharged from the cooling tower
pm, Na⁺120 ppm, Ca⁺⁺56 ppm, Cl^-2
00ppm) 35m^ThreeOther than supply
Electrodialysis was performed in the same manner as in Example 3. As a result, in the steady state,
33.5 ppm of TDS, Na⁺5pp
m, Ca⁺⁺2.4 ppm, Cl^-8.4 ppm dilution
Is 835m^Three/ Day, and TDS340
0 ppm, Na⁺510 ppm, Ca⁺⁺238 ppm,
Cl^-850 ppmconcentratedLiquid is 50m^Three/ Day.
Operation by supplying the entire amount of the above diluent as makeup water for the cooling tower
Water was supplied to the dilution chamber of the electrodialysis tank.
Is 850m^Three/DayObtained byWas. [0030] Advantageous Effects of the InventionToExtremely efficient reduction of makeup water
And thereby save water resources.AboutExtremely
It is for.

Claims (1)

(57) [Claim 1] A method of operating a cooling water tower for cooling while supplying blowdown water discharged from the system and make-up water corresponding to the amount of evaporating water to circulating water. As an anion exchange membrane
The above-mentioned blowdown water or makeup water is supplied to the dilution chamber of the electrodialysis tank using the monovalent anion selective permeable membrane, and the electricity is treated, and the monovalent anion is selected from the blowdown water or makeup water.
And the salt concentration obtained from the dilution chamber was reduced.
A method for operating a cooling water tower , comprising supplying blowdown water or makeup water to circulating water .