CN1396124A - Equipment and procedure for preparing purified water - Google Patents
Equipment and procedure for preparing purified water Download PDFInfo
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- CN1396124A CN1396124A CN 02129044 CN02129044A CN1396124A CN 1396124 A CN1396124 A CN 1396124A CN 02129044 CN02129044 CN 02129044 CN 02129044 A CN02129044 A CN 02129044A CN 1396124 A CN1396124 A CN 1396124A
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Abstract
A process for preparing the purified water from raw material includes such steps as low-pressure membrane separation, adsorption by activated carbon, electric deionizing and desalting, and filtering by microfilter membrane. Its advantages are high effect, and low energy consumption, noise and cost.
Description
Technical field
The present invention relates to a kind of production equipment and process of pure water, the production equipment and the process of the pure water that particularly a kind of low-pressure membrane combines with the electrodeionization membrane separation technique.
Background technology
According to Chinese bottled purified water for drinking hygienic standard GB17323-1998, " bottled purified water for drinking " is defined as: " with the water that meets drinking water sanitary standard is raw material; make by electroosmose process, ion exchange method, reverse-permeation process, distillation method and other suitable working methods, is sealed in the container and does not contain any additive water capable of direct drinking." for the preparation of drummed pure water, the concerned countries standard has been stipulated electrodialysis, ion-exchange, reverse osmosis, distillation and other suitable production methods equally.The most important thing is physical and chemical index " specific conductivity " and microbiological indicator in the water-quality guideline of pure water, stipulate that wherein pure electrical conductivity of water should be not more than 10 μ s/cm, total number of bacterial colony should be not more than 20cfu/mL.
In water technologies such as distillation, ion-exchange, electrodialysis, reverse osmosis, distillation is owing to high energy consumption, low water quality, shortcomings such as system is huge, operation is inconvenient, easy contaminate environment are eliminated gradually, be not re-used as at present the core process of pure water technology, but the many and purpose of other pure water technology collocation uses to realize that some are specific.Electrodialysis is under the effect of DC electric field, utilizes anion and cation exchange membrane to remove a kind of membrane sepn process that obtains de-salted water to the different choice perviousness of zwitterion in the water and with salt ion.Yet, generally can only reach the ratio of desalinization of 60-95% with electrodialytic desalting, the typical ratio of desalinization of the electrodialyzer of following industry scale is at 70-90%, for the most general be that the city tap-water of hundreds of μ s/cm is for the situation of former water with specific conductivity, product water conductivity with electrodialytic desalting then can't reach below the 10 μ s/cm, therefore must combine with ion-exchange just to make product water quality meet the requirements, and promptly takes the prepared pure water of " electrodialysis+ion-exchange ".
Prepare pure water for independent " ion-exchange " or " electrodialysis+ion-exchange " technology, unavoidable problem is exactly a chemical regeneration saturated, the ion exchange resin that lost efficacy.With chemical acid alkali ion exchange resin is regenerated and to have following distinct disadvantage:
1, it is very low to be used for regenerated chemical agent utilization ratio, and the ion that accounts for very big weight percent in used acid or the alkali does not obtain utilizing.
2, regeneration consumes a large amount of rinse water, produces a large amount of spent acid waste lye dischargings, and polluted-water and surrounding enviroment are destroyed the eubiosis.
3, regeneration system rapidly complexity, operation inconvenience.
4, water manufacturing system can not continuous operation.
In the production of current purified drinking water both domestic and external, what obtain widespread is reverse osmosis technology.Reverse osmosis is to be motivating force with pressure, the solvent in the solution (water) is separated the membrane sepn process that obtains pure water by reverse osmosis membrane.Its main separate object is the ion in the solution, also can remove molecular weight at the organism more than 300 simultaneously.In the production of present commercialization pure water, the part above 90% all is to use reverse osmosis technology, wherein generally takes the pre-treatment as reverse osmosis of ultrafiltration or micro-filtration.
Because the ratio of desalinization of reverse osmosis membrane is generally about 98%, therefore, be lower than 400 μ s/cm as specific conductivity, just then adopt first-stage reverse osmosis can obtain qualified pure water for raw water quality situation preferably; And when raw water quality is higher than 400 μ s/cm more at large, then must take two steps ro just can obtain safe, qualified product water.Take reverse osmosis technology to prepare pure water, also have two following point defects:
1, cost height
The reverse osmosis membrane and high-pressure pump, stainless steel or the glass reinforced plastic putamina that adopt cost an arm and a leg.For the water production rate of tonne scale, if adopt first-stage reverse osmosis, then production line only equipment cost just need tens thousand of units, if adopt two steps ro, then up to more than 10 ten thousand yuan.
2, water use efficiency is low excessively, and water resource waste is serious
The scale that general pure water is produced all is that hundreds of liter one is several ton/hour, and is lower.Because the water yield (utilization ratio) of single reverse osmosis membrane assembly only is about 8%, therefore for hundreds of liters/hour reverse osmosis for, its water use efficiency is lower than 20%, promptly surpassing 80% former water will be discharged; For several tons/hours reverse osmosis system, by many placed in-line methods of membrane module, its typical water use efficiency is also only about 50%, and if system design is a two steps ro, then water use efficiency will reduce greatly.This extremely low water utilization rate is very disadvantageous for the situation of current Freshwater resources growing tension.
Electrodeionization (the English EDI that is called for short) technology, it is a new membrane isolation technique using chemical acid alkali to come the defective of regenerating resin in the ion exchange process and develop in order to overcome, its principal character is to fill the mixed bed ion exchange resin in the freshwater room of electrodialyzer, under reasonably combined operational condition, just electrodialysis and ion exchange technique can be organically combined, both the effect by electric energy and ion-exchange membrane and resin realized water demineralizing, realize continuous migration and the discharge of salt ion by electric energy again simultaneously by the resin phase, and the cyclic regeneration of ion exchange resin, therefore avoided electrodialysis can not directly produce the shortcoming that pure water and ion exchange resin need use the soda acid frequent regeneration simultaneously.Compare with reverse osmosis, EDI can not remove organic impurities, but at aspects such as ratio of desalinization, water use efficiency, equipment cost, system complex degree remarkable superiority is arranged all.Patent US4632745 is that the patent of first practicability EDI technology is used, and ZL99241918.2, ZL00200207.8 etc. then is that the patent of the EDI technology of China is used.
Patent EP916620A2, US6017433 have taked the technology of " pH regulator one EDI " to carry out desalination.This patent design has been carried out the acidifying pre-treatment in order to prevent the fouling in the EDI device with the former water of EDI, promptly before Yuan Shui enters the EDI freshwater room, its pH value is adjusted to 0-3, and condensed water is water inlet separately then.Because this design regulates the pH value of former water low excessively, so EDI product water and condensed water all still be tangible acidity, so can not be as the production technique of tap water.When the core desalination process produced as pure water with EDI, then need to carry out more rational process design.
Summary of the invention
The objective of the invention is shortcoming and defect, a kind of dependable performance, easy and simple to handle, installation cost greatly reduces, water use efficiency then significantly improves pure water new process of production and device are provided at above-mentioned pure water production technology.
The objective of the invention is to realize by the following technical solutions:
Take the low pressure liquid separatory membrane to do pre-treatment, the electric deionization pure water device is the desalination core, three tandem process of microfiltration membrane end-filtration and make qualified pure water.
1, low-pressure membrane pre-treatment
Described low-pressure membrane can be ultra-filtration membrane or supermicro filtration membrane (Ultramicrofiltration Membrane), is good with ultra-filtration membrane and supermicro filtration membrane generally.The aperture of ultrafiltration (the English UF that is called for short) film then is the 0.001-0.1 micron, and molecular weight cut-off is 10
3-10
6Supermicro filtration membrane then is a kind of special ultra-filtration membrane, and separation performance is between ultrafiltration and micro-filtration, and its membrane pore size is the 0.07-0.08 micron, and pore size distribution is minimum and be evenly distributed, and membrane flux is then much larger than traditional UF.
For common be the situation of former water with city tap-water, the UF film of employing can be the UF film of organic polymer material or inorganic materials.Organic materials UF film mainly contains polysulfones and polyolefin film, as polysulfones (PS), SPSF (SPS), polyethersulfone (PES), polypropylene (PP), polyacrylonitrile (PAN) etc.; Inorganic materials UF film mainly is an inorganic ceramic film.For the present invention, above-mentioned various UF film all can be used, and its molecular weight cut-off is controlled to be 2-5 ten thousand dalton.
UF is to be motivating force with pressure, utilizes the physics sieving action that liquid is carried out isolating membrane sepn process, and its working pressure is generally 0.2-0.3MPa far below nanofiltration and reverse osmosis.Utilize above-mentioned low-pressure membrane to do pre-treatment, can effectively remove particulate, colloid, pigment, bacterium, virus and larger molecular organics in the former water, prevent the organic fouling in the downstream electrical deionization for the electrodeionization assembly in downstream.Utilize the supermicro filtration membrane assembly more can carry out the effectively isolating higher flux that obtains simultaneously.Relatively poor relatively when raw water quality, when turbidity is too high, take before low-pressure membrane, to increase the method for quartz sand filter, alleviate the pressure of low-pressure membrane, slow down its flux attenuation, prolong the use and the cleaning interval of low-pressure membrane.The filtration medium of sand-bed filter adopts the quartz sand of 0.4-1.0mm.
2, electrodeionization desalination
Make pretreated water by low-pressure membrane and enter the electrodeionization assembly, the control The reasonable operating conditions can make its ratio of desalinization reach more than 99%, and water use efficiency can reach 60-80% simultaneously.Be lower than the former water of 1000 μ s/cm for specific conductivity, can directly obtain qualified pure water.Relatively poor when raw water quality, when specific conductivity is too high, can take the multistage electrodeionization assembly of separate unit, perhaps two placed in-line methods of electrodeionization assembly obtain qualified product water.
If the organic impurities index in the former water is too high, can before the electrodeionization assembly, increase the charcoal absorption means to lower organic content, alleviate the Organic pollutants level in the EDI assembly, prolong its use and cleaning interval.
If the pH value of former water is higher, then, guarantee the safe operation of EDI in order to prevent the fouling in the EDI assembly, can the pH regulator device be set before the low-pressure membrane or between charcoal absorption and the EDI, to 5-7, is good with 5.5-6.5 with the pH regulator of former water generally, slightly slant acidity.PH regulator can use chemical agents such as dilute hydrochloric acid or dilute sulphuric acid.
3, microfiltration membrane end-filtration
Micro-filtration (the English MF that is called for short) belongs to the secondary filter technology, and pore size filter is the 0.1-75 micron, and commonly used is the 0.1-20 micron.Among the present invention, as the MF film that end-filtration is used, its material also can be cellulose acetate (CA), polymeric amide, polysulfones, polyolefins and inorganic ceramic MF film.
For the present invention, employed terminal microfiltration membrane, its pore size filter is generally 0.22 micron less than 0.45 micron, in order to hold back bacterium and particulate fully, obtains safe and reliable product water.
Each unit for treating water of the present invention is integrated as a whole, can produce following effect:
Low-pressure membrane (ultrafiltration or ultra filtration) pre-treatment can be removed particulate, colloid, pigment, microorganism and the larger molecular organics in the former water; The electrodeionization assembly can be under the condition that does not consume any soda acid the continuous high-efficient desalination, make the product water conductivity reach below the 10 μ s/cm; The terminal micro-filtrate membrane filtration can be removed bacterium and particulate, thereby makes qualified pure water.
Description of drawings
Fig. 1 is a process flow diagram of the present invention.
Among the figure:
The 1-topping-up pump; The 2-sand-bed filter; The 3-pH modulator; 4-low-pressure membrane assembly; 5-charcoal absorption filter; The 6-EDI assembly; The online conductivitimeter of 7-; The 8-micro-filtrate membrane filtration
Embodiment
Generally, the production scale of producing purified drinking water is all less, is hundreds of liters-several tons/hours.When water production rate be no more than the 1-2 ton/hour, and former water is normal city tap-water, hydraulic pressure is 0.2-0.3MPa, when water quality meets national standard, can not use former water topping-up pump and quartz sand filter, thereby equipment cost is significantly reduced.In addition, for for the EDI device of tonne scale, compare with the reverse osmosis of using high-pressure pump for water production rate, its cost still the not enough latter 25%, the water use efficiency of 60-80% then significantly improves than the latter's 15-50% simultaneously.Water production rate is more little, and it is just big more that water use efficiency differs, and uses the advantage of EDI desalination just obvious more.In addition, use low-pressure membrane-electrodeionization explained hereafter pure water, exempted the power-driven pump of greater energy consumption and high noisy in the system, even under the lower condition of water production rate, can also realize not having the quiet operation of pump, therefore compare with the reverse osmosis production technique, also have advantage energy-conservation, low noise.
The EDI assembly that uses among the present invention, its major technique characteristics are to be filled with the negative and positive mixture iron exchange resin in the freshwater room of electrodialyzer.The left and right sides of EDI assembly is the positive and negative terminal electrode, middle anion and cation exchange membrane and diluting compartment and concentration compartments for alternately arranging.The deionized ultimate principle of EDI process mainly comprises three aspects of electricity regeneration of ionic selective migration and resin under ion-exchange, the DC electric field.Ion in the former water at first is adsorbed on the resin particle because of exchange interaction, and " the ion transport passage " that constitutes via resin particle under electric field action moved to the film surface and seen through ion-exchange membrane and enter the concentration compartments again.When the polarization in the interfacial diffusion layer that resin, film contact with water develops into to a certain degree (depending on operational condition), just set up high potential gradient, forcing water decomposition is H
+And OH
-They are except that the subparticipation load current, and another part plays the in-place regeneration effect to resin again, thereby ion-exchange, ion selectivity migration, three processes of electricity regeneration are taken place together, mutually promote, and have reached the successive deionising process.Compare with ion-exchange, the major advantage of EDI is can be exempting under the chemical acid alkali regenerated prerequisite to realize that continuous desalination prepares pure water, efficient, energy-conservation, pollution-free.
Shown in Figure 1 is process flow diagram of the present invention.Former water is through topping-up pump 1 pressurization, enter quartz sand filter 2, remove big particulate, colloid and turbidity, after pH modulator 3 is regulated the pH value, purify through low-pressure membrane assembly 4-1,4-2 again, remove macromolecular organism, particulate, colloid, pigment and microorganism, its condensed water is directly discharged, and low-pressure membrane is purified waste water and enter EDI assembly 6 desalinations behind charcoal absorption filter 5, the condensed water of EDI and the discharging of utmost point water, the desalination desalination water obtains product water at last through micro-filtrate membrane filtration 8 terminal process.Wherein, between microfiltration membrane 8 and EDI, be provided with online conductivitimeter 7 in order to monitoring product water quality.
Small-sized EDI device embodiment
It is right that the EDI membrane stack contains 8 films altogether, and by two sections assemblings of one-level, the dividing plate specification is 100 * 300mm, membrane stack operating voltage 20-25V, working current 150-200mA, 10 liters/hour of the fresh water production water yields, EDI water use efficiency 60%.Different time adopt former water and product electrical conductivity of water data, and the zwitterion content detection data in the desalination water are respectively as shown in the table: the former water of table one, EDI desalting process and desalination electrical conductivity of water (μ s/cm)
The water quality compositional analysis (ppm) of table two, EDI desalination water
| Former water 680 665 670 708 668 620 660 582 620 |
| Desalination water 4.6 3.0 3.9 4.4 3.6 3.8 8.7 6.4 4.0 |
| ????K | ????Na | ????Ca | ????Mg | ??Cu | ??Zn |
| ????6.36 ????Fe ????＜0.001 | ????4.81 ????Si ????0.148 | ????0.830 ????F -????0.010 | ????0.208 ????Cl -????0.790 | ??＜0.001 ??NO 3 -??0.011 | ??0.467 ??SO 4 2-??0.130 |
As seen, be lower than the former water of 800-1000 μ s/cm,, then must adopt the technology of two steps ro if use reverse osmosis technology to prepare pure water for specific conductivity; And in most cases, use EDI to carry out desalination, and then only need one-level EDI device just can obtain the pure water of specific conductivity below 10 μ s/cm, its equipment cost greatly reduces.
Pure water production technique provided by the present invention, compared with prior art, its major advantage is that equipment cost greatly reduces, water use efficiency significantly improves, simultaneously device simple, be convenient to operation and maintenance, reliable, energy-saving and low noise, so easy to utilize.
Claims (3)
1, a kind of production equipment of pure water and process, it is to be former water with city tap-water, make pure water through sand filtration, low-pressure membrane pre-treatment, charcoal absorption, electrodeionization desalination and microfiltration membrane end-filtration process successively, it is characterized in that: sand filtration is to be that the sand-bed filter of the quartz sand of 0.4-1.0mm is finished by adopting filtration medium; Low-pressure membrane is to be 2-5 ten thousand daltonian ultra-filtration membranes by adopting molecular weight cut-off, and perhaps membrane pore size is that the membrane module of the supermicro filtration membrane of 0.07-0.08 μ m is finished; Desalination is by adopting ratio of desalinization to finish greater than 99% electrodeionization assembly; End-filtration is to be that the micro-filtration membrane module of 0.22-0.45 μ m is finished by adopting pore size filter, and before the low-pressure membrane assembly, or before the electrodeionization assembly, the pH modulator of water being set, the pH value of regulating water with dilute hydrochloric acid or dilute sulphuric acid is 5.5-6.5.
2, the production equipment of a kind of pure water according to claim 1 and process is characterized in that, employed ultra-filtration membrane, its membrane material are polysulfones, perhaps a kind of in SPSF, polyethersulfone, polypropylene, polyacrylonitrile and the inorganic ceramic material.
3, the production equipment of a kind of pure water according to claim 1 and process is characterized in that, employed microfiltration membrane, and its membrane material is a kind of in cellulose acetate, polymeric amide, polysulfones or the inorganic ceramic material.
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| CN 02129044 CN1396124A (en) | 2002-08-29 | 2002-08-29 | Equipment and procedure for preparing purified water |
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| CN 02129044 CN1396124A (en) | 2002-08-29 | 2002-08-29 | Equipment and procedure for preparing purified water |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101954221A (en) * | 2010-08-23 | 2011-01-26 | 张亚宁 | Tap water source filter device |
| CN101475275B (en) * | 2008-01-04 | 2011-04-20 | 财团法人工业技术研究院 | Water recovery processing system and water recovery processing method |
| CN102936069A (en) * | 2012-12-04 | 2013-02-20 | 天津中天海盛环保科技有限公司 | Ultrawater purifier for lab |
| CN104086036A (en) * | 2014-07-25 | 2014-10-08 | 马鞍山市西满塑料包装有限公司 | Water treatment method |
| CN104507875A (en) * | 2012-08-03 | 2015-04-08 | 三菱重工机电系统株式会社 | Water treatment device |
| US20150175448A1 (en) * | 2013-12-19 | 2015-06-25 | Benq Materials Corporation | System for treating wastewater containing boron and iodine |
| CN104743716A (en) * | 2015-03-02 | 2015-07-01 | 陈永军 | Application of concentrated polar water circulating frequent electrodialysis reversal (EDR) technology in domestic water purification equipment |
| CN107445259A (en) * | 2017-09-20 | 2017-12-08 | 江苏科技大学 | A kind of small-sized household capacitive deionization water purifier |
-
2002
- 2002-08-29 CN CN 02129044 patent/CN1396124A/en active Pending
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101475275B (en) * | 2008-01-04 | 2011-04-20 | 财团法人工业技术研究院 | Water recovery processing system and water recovery processing method |
| CN101954221A (en) * | 2010-08-23 | 2011-01-26 | 张亚宁 | Tap water source filter device |
| CN104507875A (en) * | 2012-08-03 | 2015-04-08 | 三菱重工机电系统株式会社 | Water treatment device |
| US9718715B2 (en) | 2012-08-03 | 2017-08-01 | Mitsubishi Hitachi Power Systems Environmental Solutions, Ltd. | Water treatment device |
| CN104507875B (en) * | 2012-08-03 | 2018-04-27 | 三菱日立电力系统环保株式会社 | Water treatment facilities |
| CN102936069A (en) * | 2012-12-04 | 2013-02-20 | 天津中天海盛环保科技有限公司 | Ultrawater purifier for lab |
| US20150175448A1 (en) * | 2013-12-19 | 2015-06-25 | Benq Materials Corporation | System for treating wastewater containing boron and iodine |
| CN104086036A (en) * | 2014-07-25 | 2014-10-08 | 马鞍山市西满塑料包装有限公司 | Water treatment method |
| CN104086036B (en) * | 2014-07-25 | 2016-05-18 | 马鞍山市西满塑料包装有限公司 | A kind of method for treating water |
| CN104743716A (en) * | 2015-03-02 | 2015-07-01 | 陈永军 | Application of concentrated polar water circulating frequent electrodialysis reversal (EDR) technology in domestic water purification equipment |
| CN107445259A (en) * | 2017-09-20 | 2017-12-08 | 江苏科技大学 | A kind of small-sized household capacitive deionization water purifier |
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