CN1440933A - Desalting method and desalting device - Google Patents
Desalting method and desalting device Download PDFInfo
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- CN1440933A CN1440933A CN02105330A CN02105330A CN1440933A CN 1440933 A CN1440933 A CN 1440933A CN 02105330 A CN02105330 A CN 02105330A CN 02105330 A CN02105330 A CN 02105330A CN 1440933 A CN1440933 A CN 1440933A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/124—Water desalination
- Y02A20/131—Reverse-osmosis
Abstract
The present invention is desalting method of water and especially sea water. Several membrane assmblies are set in a series, permeated water from the first stage of the membrane assemblies is fed to the second stage to obtain further permeated water. The desalting process includes: the influent water processing step to process at least partial influent water and mix the processed water and other part of influent water to obtain processed water with salt concentration of 65-90 of the influent water and calcium ion concentration of 70% or lower of the influent water; and the step to feed the water processed in the first step to the second stage of membrane assembly. The apparatus for the processing includes at least the first and the second membrane assemblies.
Description
Technical field
The present invention relates to a kind of desalting method and desalter that utilizes particularly hyperfiltration of membrane module (nanofiltration) film and reverse osmosis membrane, be applicable to high-recovery and produce fresh water by seawater.
Background technology
In recent years, the technology that is obtained service water or tap water by liquid such as seawater or high dense salt water is developed, replaces traditionally the generally method of evaporation of use, utilizes the sea water desalination method of reverse osmosis membrane to receive publicity.Estimate that this reverse osmosis membrane sea water desalination method can because it is minimum to produce the required energy of fresh water, and can obtain high-quality fresh water in each field application.
In normal reverse osmosis sea water desalinization, the seawater that to supply with reverse osmosis membrane assembly with high-pressure pump is forced into about 6.0 to 6.5MPa, thereby obtain infiltration water (typically being fresh water), but reclaim the rate of recovery (percentage) maximum about 40% of fresh water in the case by the seawater of supply." fresh water " should satisfy drinking water standard, and dissolved solute total amount is 500ppm or lower." rate of recovery " is the fresh water volumetric ratio of unit volume by the water inlet generation of desalter processing.For sea water desaltination, described water inlet is a seawater.
In sea water desaltination, fresh-water recovery rate directly influences the desalination cost, so the rate of recovery is high more good more.But the actual increase of the normal reverse osmosis seawater desalting rate of recovery is limited.That is, improve the rate of recovery, need high pressure.This causes following problem: the difference of pressing in the osmotic pressure and the driving of assembly upstream seawater under the low situation of water supply salt concn is too big, the amount of seepage of reverse osmosis membrane is too big, contained external component (suspended substance) is stopped up reverse osmosis membrane rapidly in the water supply, thereby causes degradation.
For addressing the above problem, JP-A-08-108048 discloses a kind of device that comprises multistage reverse osmosis membrane assembly, wherein make pressure rising from the condensed water of first step reverse osmosis membrane assembly, infeed second stage reverse osmosis membrane assembly, operation is carried out the method that sea water desaltination prevents the degradation of reverse osmosis membrane simultaneously so that every grade working pressure is not too high thereby provide with high-recovery so simultaneously.Arrange by this, for example under the about 9.0MPa of pressure of about 6.5MPa of the pressure of first step reverse osmosis membrane assembly and second stage reverse osmosis membrane assembly, operate can 60% the rate of recovery be 3.5% seawater acquisition fresh water by salt concn.
Yet, promptly use above method described in the JP-A-08-108048, about 60% also is the upper limit of fresh-water recovery rate.This has two reasons.First, the concentration increase that fresh-water recovery rate raises and causes the reverse osmosis membrane concentrated seawater, the concentration that is included in so-called dirt component in the seawater such as calcium sulfate under about 65% the rate of recovery surpasses the dissolving limit of material balance, cause this dirt component to be deposited on the reverse osmosis membrane, thereby film is stopped up with the dirt form.The second, because of salt concn raise due to the osmotic pressure 9.0MPa that raises and require pressure even be higher than operation second stage membrane module.
Summary of the invention
Therefore, the present invention is devoted to the problems referred to above of conventional art, attempt to provide a kind of with in addition the higher rate of recovery produce the desalting method and the desalter of fresh water by seawater with stationary mode.
For this reason, the invention provides a kind of method that in being provided with multistage (promptly two-stage) at least of membrane module unit separately, makes water desalination, wherein the infiltration water from first step membrane module unit infeeds the infiltration water of second stage membrane module unit by its acquisition desalination, described method comprises: the first step, the processing total salt concentration is that 3.0-4.8% (weight) and calcium ion concn are 200 to 500mg/l water inlet, in the first step, handle at least a portion water inlet and obtain infiltration water with first step membrane module unit, described infiltration water is mixed with other water inlet, is the 55-90% of described water inlet thereby make the total salt concentration of described the first step treated water, calcium ion concn be described water inlet 95% or lower; With second step, described the first step treated water is infeeded second stage membrane module unit, thereby obtain the water of desalination.
Below in conjunction with accompanying drawing the preferred embodiments of the invention are described, wherein:
Fig. 1 is the desalter schema of explanation one embodiment of this invention;
Fig. 2 is the desalter schema that explains another embodiment of the present invention;
Fig. 3 is the schema of explanation reverse osmosis membrane assembly unit structure, and described reverse osmosis membrane assembly unit is the modification of embodiment of the present invention shown in Figure 2; With
Fig. 4 is the schema of another structure of explanation reverse osmosis membrane assembly unit, and described reverse osmosis membrane assembly unit is the another kind of modification of embodiment of the present invention shown in Figure 2.
Use following mark among Fig. 1 to 4:
1: seawater stream
2: clarifying plant
3: the hyperfiltration membrane module unit
3a: first step hyperfiltration membrane module
3b: second stage hyperfiltration membrane module
4: topping-up pump
5: the water inlet bypass passageways
6: from the infiltration current of hyperfiltration membrane module unit
7: mixing tank
8: supply with the unitary current of reverse osmosis membrane assembly
9: the reverse osmosis membrane assembly unit
9a: first step reverse osmosis membrane assembly
9b: second stage reverse osmosis membrane assembly
10: high-pressure pump
11: from the unitary infiltration current of reverse osmosis membrane assembly
12: from the thickened waste current of hyperfiltration membrane module unit
13: from the unitary thickened waste current of reverse osmosis membrane assembly
14: energy recycle device
15: from the concentrated current of first step reverse osmosis membrane assembly
16: supercharging device
17: the scale inhibitor injection device
In the desalination process of the present invention, any film that can regulate salt and calcium ion concentration all can be used for multistage The membrane module unit that arranges, its example comprises that reverse osmosis membrane, amberplex and electric charge inlay (mosaic) film, but what be specially adapted to the first order is that separative efficiency is good and can be under lower pressure The hyperfiltration film unit of operation. What in addition, be applicable to the second level is that salt rejection rate is high and can provide a large amount of The reverse osmosis membrane unit of infiltration water.
First order hyperfiltration membrane module unit itself can have a plurality of (namely at least two) to be arranged on a plurality of The assembly in the substate separately, thus will feed from the condensed water of the first substate hyperfiltration membrane module the Two substate hyperfiltration membrane modules obtain infiltration water. Equally, also availablely be arranged on a plurality of separately substates In the reverse osmosis membrane assembly of a plurality of assemblies as reverse osmosis membrane assembly unit, the second level, wherein from The condensed water of one substate reverse osmosis membrane assembly feeds the second substate reverse osmosis membrane assembly and obtains infiltration water. Special Not preferably feed the second substate reverse osmosis membrane group in the condensed water from the first substate reverse osmosis membrane assembly Part improves the pressure of described condensed water before to obtain infiltration water. In addition, the first substate reverse osmosis membrane group Between the operating pressure P (n) of part and the operating pressure P (n+1) of the second substate reverse osmosis membrane assembly Relation is preferred in the given scope of following formula:
1.15≤P(n+1)/P(n)≤1.8。
In the above-mentioned desalination process, preferably before carrying out hyperfiltration to supplying with hyperfiltration membrane module list Inject scale preventative in the water of unit, because produce can prevent from using the high hyperfiltration film of calcium ion removal efficiency the time Give birth to calcium sulfate dirt and can improve the rate of recovery.
In addition, preferably use filtered water that micro-filtration (microfiltration) or ultrafiltration membrane treatment cross, can alleviate because of the hyperfiltration film pollutes and cause degradation as the water inlet that is provided.
Use desalting method of the present invention, 30 to 100%, more preferably 35 to 95% even more preferably 40 to 90% of water inlet can be handled with first step membrane module unit, is untreated into remaining that water mixes then, infeeds second stage membrane module unit.
In addition, according to the present invention, described desalting method preferably carry out like this so that the percentage (based on the water yield that infeeds first step membrane module unit) of first step membrane module unit gained amount of seepage in 65% to 95% scope, more preferably 75 to 90%, even the percentage (based on the water yield that infeeds second stage membrane module unit) that more preferably makes second stage membrane module unit gained amount of seepage is in 70 to 85% scope.
In addition, described desalting method preferably carry out like this so that based on the water inlet total amount from the percentage (so-called total yield) of the amount of seepage of second stage membrane module unit in 60% to 80% scope, more preferably 65 to 75%.
In addition, for realizing above-mentioned desalting method, desalter of the present invention comprises:
Respectively at least the first and second membrane module unit that are used for water infiltration of first and second grades of successive,
As described first film unit of the first step, the hyperfiltration membrane module unit has membrane module and through the output channel of the water of its infiltration,
As partial described second film unit, the reverse osmosis membrane assembly unit is arranged in the infiltration water output channel of described hyperfiltration membrane module unit;
Thereby be used to make the part water inlet of supplying with the described hyperfiltration membrane module unit of pointing to described output channel to turn to the device of walking around described membrane module; (preferably)
In described output channel, be used to make the water blended device of described part water inlet in the hyperfiltration membrane module infiltration of the upstream, reverse osmosis membrane assembly unit, the second stage and the first step.
Preferred embodiment of the present invention comprises:
First step membrane module unit, the hyperfiltration membrane module unit more preferably has a plurality of assemblies in a plurality of substates separately,
The second stage membrane module unit of reverse osmosis membrane assembly unit form also has a plurality of assemblies in a plurality of substates separately, is arranged in the permeate channel of described hyperfiltration membrane module unit,
Be used to make the device of the part water inlet bypass of supplying with described hyperfiltration membrane module unit, and (more preferably)
Be used to make described bypass water inlet and infiltration water blended device from described hyperfiltration membrane module unit, described mixing device is arranged in the unitary water channel of described reverse osmosis membrane assembly.
In the above-mentioned desalter, more preferably described first step hyperfiltration membrane module unit has a plurality of assemblies in substate separately, and the second substate hyperfiltration membrane module is arranged in the condensed water passage of the first substate hyperfiltration membrane module.Explain in each substate separately, at least one assembly is arranged as following, but in any substate, particularly described first substate can there be a plurality of assemblies parallel with one another.In addition, the relation between total film surface-area S1 (n+1) of total film surface-area S1 (n) of described or each first substate hyperfiltration membrane module and described or each second substate hyperfiltration membrane module is preferably in the given scope of following formula:
1.5≤S1(n)/S1(n+1)≤5。
Similarly, second stage reverse osmosis membrane assembly unit more preferably have a plurality of be arranged in the substate separately assembly so that the second substate reverse osmosis membrane assembly be arranged in the condensed water passage of the first substate reverse osmosis membrane assembly.Explain in each substate separately, at least one assembly is arranged as following, but in any substate, particularly described first substate can there be a plurality of assemblies parallel with one another.In addition, the relation between total film surface-area S2 (n+1) of total film surface-area S2 (n) of described or each first substate reverse osmosis membrane assembly and described or each second substate reverse osmosis membrane assembly is preferably in the given scope of following formula:
1.67≤S2(n)/S2(n+1)≤2.5。
In addition, the supercharging device that is used for improving condensed water pressure preferably is arranged in each the condensed water passage of the condensed water passage of described reverse osmosis membrane assembly of last reverse osmosis membrane assembly upstream or a plurality of reverse osmosis membrane assemblies.
In addition, the scale inhibitor injection device preferably is arranged in the passage of supply water inlet of described hyperfiltration membrane module unit.
In addition, micro-filtration membrane module unit or hyperfiltration membrane assembly unit preferably are arranged in the passage of supply water inlet of described hyperfiltration membrane module unit.
Below in conjunction with accompanying drawing embodiment of the present invention are described.One embodiment of desalter of the present invention is described in conjunction with Fig. 1.Among Fig. 1, described desalter comprises the clarifying plant 2 that is used for removing from described water inlet one seawater (streamline 1) suspended substance, hyperfiltration membrane module unit 3 and be used for force (forcing) pump 4 to the water inlet pressurization of the supply of described hyperfiltration membrane module unit 3, be used to make the bypass passageways 5 of the part water inlet bypass of supplying with described hyperfiltration film unit 3, be used to make infiltration water (streamline 6) and described bypass water inlet blended mixing device 7 from the hyperfiltration membrane module unit, the reverse osmosis membrane assembly unit 9 that is used to make feedwater (streamline 8) desalination and obtains infiltration water 11, with the high-pressure pump 10 that is used for to feedwater 8 pressurizations of described reverse osmosis membrane assembly unit 9.In this embodiment, in each hyperfiltration and the reverse osmosis membrane assembly unit, described assembly is all provided by single component.
Here, with regard to first step hyperfiltration membrane module unit 3, perhaps the water inlet of all supplies is all handled through hyperfiltration, and perhaps part water inlet is handled through hyperfiltration, passes through mixing device 7 through the water inlet of bypass passageways 5 bypass and mixes with the infiltration water (streamline 6) of hyperfiltration film.At this moment, the total salt concentration of supplying with the feedwater (streamline 8) of reverse osmosis membrane assembly unit, the second stage 9 is adjusted to 55 to 90% of described water inlet, calcium ion concn be adjusted to equally described water inlet 95% or lower.Also preferably sulfate ion concentration is adjusted to described water inlet 80% or lower, this amount is generally 1500 to 3500mg/l in seawater.
The reason of the solute concentration of control feedwater 8 is as follows.If total salt concentration is in above-mentioned scope, then the osmotic pressure of the feedwater 8 of second stage reverse osmosis membrane assembly unit 9 descends, can set the working pressure of reverse osmosis membrane lower, thereby can reduce the current consumption of high-pressure pump 10, also can reduce the pressure load on the reverse osmosis membrane, this means the life-span that can prolong reverse osmosis membrane or under identical operations pressure, can the higher rate of recovery obtain more infiltration water.In addition, if calcium ion concn in above-mentioned scope, then can be suppressed at the calcium sulfate (CaSO of reverse osmosis membrane surface scale under high-recovery
4) precipitation, thereby can improve the infiltration water rate of recovery of using reverse osmosis membrane assembly unit 9.
The type or the performance of hyperfiltration film do not have particular restriction, any hyperfiltration film all is suitable for, as long as all water inlets are handled or the part water inlet is handled then with after the water inlet of bypass mixes through hyperfiltration through the hyperfiltration film, total salt concentration is 55 to 90% of described water inlet, calcium ion concn be described water inlet 95% or lower; But the preferred hyperfiltration film that forms by such as polymeric amide, poly-piperazine amide, polyesteramide and crosslinked materials such as water-soluble ethylene based polyalcohol that uses.In addition, about membrane structure, the preferred film that uses at least one side that tight zone is arranged, described film have diameter inboard or to the pore (being asymmetric membrane) that the opposite side of film enlarges gradually to film from described tight zone, perhaps form the film of separating layer as thin as a wafer with differing materials on the tight zone of this asymmetric membrane.In addition, when selecting preferred mould material, the film that should remember to produce relatively large filtered water under lower pressure is more economical.Therefore, consider special preferred polyamide film from aspects such as amount of seepage and chemical proofings, more preferably poly-piperazine amide film.
The dull and stereotyped film formed element that described hyperfiltration film can be made into the spiral winding element of flat sheet membrane around the collection tube, stretch in the both sides of tabular back up pad is tied up bunchy by intervenient dividing plate with the plate and frame element of predetermined space stratification assembly, the tube element that uses tubular film or tubular fibre and is stored in hollow fibre membrane component in the container, and one or more element linear connects also and is stored in the pressure vessel.Described element can be taked above-mentioned any form, but sees preferred use spiral winding element from operability.The quantity of element can be set arbitrarily according to the performance of film.Under the situation of using spiral winding element, in series be arranged on a number of elements in the assembly and be preferably about 4 to 6.
In addition, performance about the hyperfiltration membrane element, preferred layout like this, wherein filter under the condition that 25 ℃ total salt concentration is 3.5% seawater with the rate of recovery of the working pressure of 1.5MPa and 13%, ratio of desalinization (TDS (Total Dissolved Solids): evaporation residue) in 30 to 80% scope, the calcium ion decreasing ratio is in 20 to 80% scope, and the decreasing ratio of sulfate ion is 95% or higher, the seepage discharge of film 0.3 to 1.5m
3/ m
2In the scope of/d, because can realize the total salt concentration and the calcium ion concn scope of above-mentioned feedwater (streamline 6) easily.Arrange like this that more preferably wherein ratio of desalinization is in 35 to 70% scope, the calcium ion decreasing ratio is in 30 to 60% scope, and the decreasing ratio of sulfate ion is 97% or higher.
Water inlet ratio by bypass can be set arbitrarily, as long as total salt concentration and calcium ion concn scope satisfy the requirement of above-mentioned feedwater (streamline 8), the bypass amount is big more, and the amount of handling in described hyperfiltration film is more little, thereby hyperfiltration institute energy requirement (electric power) is less.But then, if the bypass amount is too big, the total salt concentration that then need reduce hyperfiltration membrane permeation water is adjusted in the above-mentioned scope to incite somebody to action back blended total salt concentration, thereby needs the rate of recovery of the working pressure or the reduction hyperfiltration membrane permeation water of rising hyperfiltration film, and this is uneconomic.Therefore, preferable range be with the hyperfiltration membrane module unit handle 30 to 100% water inlet then with bypass be untreated into that water mixes, more preferably 35 to 95%, more preferably 40 to 90%.
Being used to make hyperfiltration membrane permeation water and bypass water inlet blended mixing device 7 no particular restriction, can be the tempering tank that for example disposes in the equipment or such as devices such as static mixers.
As for the infiltration water rate of recovery of first step hyperfiltration membrane module unit 3, the total salt concentration of gained infiltration water is low under the lower situation of the rate of recovery, but is difficult to obtain the water of predetermined amount, so total yield can not improve.In addition, if the rate of recovery is too high, total yield is easy to improve, but is difficult to reduce the salt concn of the infiltration water of hyperfiltration film, thereby can not improve the rate of recovery of reverse osmosis membrane assembly unit, the second stage 9.Therefore, from the amount of seepage of hyperfiltration membrane module unit 3 with respect to the ratio of the water yield of supplying with hyperfiltration membrane module unit 3 preferably in 65 to 95% scope, more preferably in 75 to 90% scope.
In addition, for operating first step hyperfiltration membrane module unit 3 effectively with the predetermined rate of recovery, the preferred employing as shown in Figure 2 arranged, wherein a plurality of hyperfiltration membrane modules are arranged in the substate, the first substate hyperfiltration membrane module 3a is to second substate hyperfiltration membrane module 3b supply condensed water, thus the acquisition infiltration water.In embodiment shown in Figure 2, two first such substate hyperfiltration membrane modules in parallel are to a substate hyperfiltration membrane module supply condensed water.At this moment, the relation between the film surface-area S1 (n+1) of the total film surface-area S1 (n) of each first substate hyperfiltration membrane module 3a and the second substate hyperfiltration membrane module 3b preferably following formula (1) in the given scope:
1.5≤S1(n)/S1(n+1)≤5 (1)。
As mentioned above, the membrane area that the first and second substate hyperfiltration membrane modules are set can improve the interior film surface velocity of membrane module, can suppress because of strainability variation due to the concentration polarization phenomenon on hyperfiltration film surface, thereby can under high-recovery, keep the total salt concentration of infiltration water lower.Outside the scope of formula (1) defined, may cause the strainability variation because of film surface velocity deficiency, if perhaps flow velocity is too fast, then the pressure-losses in the assembly may be too big, the danger that has assembly to be out of shape or to damage in the case.
Substate quantity about the hyperfiltration membrane module, substate quantity is big more, then can get over the film surface velocity of setting every grade clearly, thereby is easy to show the filtration capacity of hyperfiltration film, but the too many increase of substate quantity causes the complicated and increase cost of unit configuration, thereby uneconomical.Consider that from this respect actual substate quantity is about 2 to 4.
In any given substate, a plurality of hyperfiltration membrane modules can be arranged in parallel, and the water that infeeds can distribute betwixt.For example, as previously described, first substate has two assemblies among Fig. 2, introduces from the condensed water of each assembly in the single component of second substate.No matter the component count of each substate is how, all preferably walk around all component in downstream from the penetrant of assembly in the substate of front, introduce in the penetrant streamline from last substate assembly.
The type that is used for the topping-up pump 4 of hyperfiltration membrane module unit 3 does not have particular restriction, and various types of pumps all can use, as impeller pump, spiral pump, turbo-pump and ram pump.
Subsequently, in the second reverse osmosis membrane assembly unit 9, to be forced into the predetermined pressure of the osmotic pressure that is equal to or greater than described infiltration water from the feedwater (streamline 8) of first step hyperfiltration membrane module unit 3 with topping-up pump 10, with the desalination of reverse osmosis membrane assembly unit, be separated into infiltration water (streamline 11) and concentrated waste water (streamline 13).
Any reverse osmosis membrane all is suitable for, as long as optionally infiltration water also can prevent whole salt penetrations.About membrane structure, the preferred asymmetric membrane that uses, its at least one side has tight zone, the pore that has diameter to enlarge gradually to the opposite side of film from described tight zone, the composite membrane of the active layer as thin as a wafer that perhaps useful differing materials forms on the tight zone of described asymmetric membrane.The material that can be used for described film comprises cellulose acetate polymers, polymeric amide, polyester, polyimide, vinyl polymer and other similar polymer materials.The preferred representational reverse osmosis membrane that uses includes the composite membrane of rhodia or polymeric amide asymmetric membrane and polymeric amide or polyureas active layer and the composite membrane of aromatic poly active layer is arranged.Wherein, the composite membrane of special preferred aramid because even under the situation that water quality changes, also show stable performance, and can suitably remove environmental hormones such as objectionable impurities such as haloform.
The same with the hyperfiltration film, spendable reverse osmosis membrane form comprises spiral winding element, plate and frame element, tube element and hollow fibre membrane component, though any form all can be used, considers the preferred spiral winding element that uses from operability.The quantity of element can be set arbitrarily according to the performance of film, under the situation of using spiral winding element, in series is arranged on the number of elements that forms single component in the pressurized vessel and is preferably about 4 to 6.
In addition, performance about reverse-osmosis membrane element, preferred setting like this, wherein filtering 25 ℃ total salt concentration with the rate of recovery of the working pressure of 5.5MPa and 13% is that 3.5% seawater carries out under the condition of reverse osmosis isolation, ratio of desalinization (TDS: be 99% or higher the evaporation of residual substrate concentration), the seepage discharge of film 0.3 to 1.5m
3/ m
2In the scope of/d, because the water quality of described infiltration water is good and can obtain infiltration water effectively.
About the infiltration water rate of recovery of above-mentioned reverse osmosis membrane assembly unit 9, this rate of recovery is high more, and total yield is high more, and this wishes, if but this rate of recovery is too high, and then action required pressure uprises, and the water quality of gained infiltration water is variation also, so this is uneconomic.In addition, the described rate of recovery is provided with to such an extent that the lower water quality of gained infiltration water that makes improves, but the gained water yield is few, and total yield descends, and is also uneconomical.Therefore, be suitably for 70 to 85% from the unitary amount of seepage of reverse osmosis membrane assembly with respect to the ratio of supplying with the unitary water yield of reverse osmosis membrane assembly.
In addition, for operating described reverse osmosis membrane assembly unit 9 effectively with the predetermined rate of recovery, the preferred employing as shown in Figure 2 arranged, wherein a plurality of reverse osmosis membrane assemblies are arranged in the substate, the first substate reverse osmosis membrane assembly 9a is to second substate reverse osmosis membrane assembly 9b supply condensed water, thus the acquisition infiltration water.In embodiment shown in Figure 2, two first such substate reverse osmosis membrane assemblies in parallel are to one second substate reverse osmosis membrane assembly supply condensed water.At this moment, the relation between the film surface-area S2 (n+1) of total film surface-area S2 (n) of described or each first substate reverse osmosis membrane assembly 9a and described or each second substate reverse osmosis membrane assembly 9b preferably following formula (2) in the given scope:
1.67≤S2(n)/S2(n+1)≤2.5 (2)。
As mentioned above, the membrane area of setting the first and second substate reverse osmosis membrane assemblies can improve the film surface velocity of second stage membrane module, can suppress because of separation performance variation due to the concentration polarization phenomenon on reverse osmosis membrane surface, thereby the water quality that can make infiltration water under high-recovery keeps higher, and can suppress to reduce because of the amount of seepage that causes that descends of working pressure due to the concentration polarization.Outside the scope of formula (2) defined, may damage infiltration water quality or water production rate because of the film surface velocity is not enough, if perhaps flow velocity is too fast, then the pressure-losses in the assembly may be too big, the danger that has assembly to be out of shape or to damage in the case.
About the unitary substate quantity of reverse osmosis membrane assembly, substate quantity is big more, then can get over the film surface velocity of setting every grade clearly, thereby is easy to show the filtration capacity of reverse osmosis membrane, but the too many increase of substate quantity causes the complicated and increase cost of unit configuration, thereby uneconomical.Consider that from this respect actual substate quantity is about 2 to 4.
In any given substate, a plurality of reverse osmosis membrane assemblies can be arranged in parallel, and the water that infeeds can distribute betwixt.For example, as shown in Figure 2, first substate has two such assemblies, introduces from the condensed water of each assembly in the single component of second substate.No matter the component count of each substate is how, all preferably walk around all component in its downstream from the penetrant of assembly in the substate of front, introduce in the penetrant streamline from last substate assembly.
Working pressure about reverse osmosis membrane assembly in each substate, enough efficient manner is operated the second substate reverse osmosis membrane assembly from the working pressure of the feedwater of the first substate assembly and is obtained infiltration water by only using, and supercharging device is not set separately, thereby described condensed water is infeeded layout that the second substate reverse osmosis membrane assembly obtains infiltration water more preferably but the supercharging device 16 that is used for improving the pressure of condensed water passage 15 condensed water as shown in Figure 3 between the unitary first substate reverse osmosis membrane assembly 9a of reverse osmosis module and the second substate reverse osmosis membrane assembly 9b raises described working pressure, because the separation efficiency of reverse osmosis membrane assembly further improves in each substate, can obtain infiltration water economically.At this moment, about the working pressure of each substate, the relation between the working pressure P (n) of the first substate reverse osmosis membrane assembly and the working pressure P (n+1) of the second substate reverse osmosis membrane assembly preferably following formula (3) in the given scope:
1.15≤P(n+1)/P(n)≤1.8 (3)。
In addition, for example under the total salt concentration of seawater is 3.5% situation, described reverse osmosis membrane assembly action required pressure is 5.5 to 7.0MPa under 40% the rate of recovery, be 8.5 to 10.0MPa under 60% the rate of recovery, but use the present invention, the total salt concentration of supplying with the seawater of described reverse osmosis membrane assembly has been reduced to about 2.0 to 3.1% by the hyperfiltration film, so working pressure can be lower than the routine operating pressure under the identical rate of recovery.Concrete working pressure is according to the concentration of water inlet, the adjusting of total salt concentration and the rate of recovery in the reverse osmosis membrane assembly unit 9 are suitably selected in hyperfiltration membrane module unit 3; But regulating with hyperfiltration membrane module unit 3 under the situation that total salt concentration for example is 3.5% seawater, be 80% reverse osmosis membrane assembly unit, 9 supply total salt concentrations when being 2.5% seawater to the rate of recovery, working pressure is fit to be set in 8.0 to 9.5MPa the scope.
Various types of pumps all can be used for the high-pressure pump 10 of reverse osmosis membrane assembly unit 9, as impeller pump, spiral pump, turbo-pump and ram pump.In addition, described supercharging device 16 can use topping-up pump such as impeller pump or spiral pump under being provided with a plurality of reverse osmosis membrane assembly substates and making from the situation of the condensed water supercharging of the first substate reverse osmosis membrane assembly.
In addition, as previously described, the working pressure of reverse osmosis membrane assembly unit 9 is high, and for example about 8.0 to 9.5MPa, and the condensed water of discharging from this unit also has approximately uniform pressure.Therefore, as shown in Fig. 2 and 3, the pressure energy that energy recycle device 14 reclaims condensed water is set preferably.As energy reclaiming method several different methods is arranged,, can use any method as reversing pump, Pelton turbine, turbocharger and pressure convertor.
The another kind of method of recovered energy is that the pressure of energy recycle device 14 with the condensed water of first substate that improves a plurality of reverse osmosis membrane assembly substates is set as shown in Figure 4.In the case, as energy recycle device (for example be disclosed in JP-A-01-294903 in), this is preferred with turbocharger, but because the structure of simplified apparatus and working method.
Described evaluation method selecting optimal equipment like this operation so that be illustrated in the percentage form of flooding quantity by the final amount of seepage of reverse osmosis membrane assembly unit 9 gained in 60% to 80% the scope, more preferably 65% to 75%.
Now, in the condensed water side of hyperfiltration film and reverse osmosis membrane, the concentration that the salt concn increase also is accompanied by calcium ion and sulfate ion increases, and they are fouling components.At this moment,, then be deposited on the film surface, cause the film properties variation with the calcium sulfate dirt form if these two kinds of ionic concentration increase.We prove by experiment and cause the sedimentary ionic concn boundary of calcium sulfate dirt to be: the about 1200mg/l of calcium ion, the about 2900mg/l of sulfate ion as long as described ionic concn does not surpass above-mentioned value simultaneously, does not then have the danger of dirt at the film surface precipitation.
According to the present invention, can regulate the operational condition of hyperfiltration membrane module unit and the ratio of mixture of intaking with bypass, and can set the unitary operational condition of reverse osmosis membrane assembly as the rate of recovery so that as described in the reverse osmosis membrane surface precipitating action of calcium sulfate dirt does not take place, thereby in reverse osmosis membrane assembly, do not have any problem relevant with dirt precipitation.On the other hand, in hyperfiltration membrane module side, as previously described, the calcium ion decreasing ratio difference relevant with the ability of used hyperfiltration film is very big.Therefore, though use the lower hyperfiltration film of calcium ion decreasing ratio to be difficult for taking place dirt at hyperfiltration film surface precipitation, because even the calcium ion concn of the concentration side of described hyperfiltration film also is difficult for uprising under high-recovery, but when using the high hyperfiltration film of calcium ion decreasing ratio, the condensed water side calcium ion concn that has a hyperfiltration film surface uprises and the sedimentary danger of calcium sulfate dirt takes place.Therefore, when using the high hyperfiltration film of calcium ion decreasing ratio, preferably in the water inlet of supplying with the hyperfiltration membrane module unit, add and prevent the dirt precipitation agent, operate this equipment.
Position as for the described scale inhibitor of injection, thereby with scale inhibitor is directly injected water inlet and also scale inhibitor is introduced described bypass-side and compared, shown in mark among Fig. 1 17, the scale inhibitor that need add when being close to injection before the hyperfiltration membrane module unit after telling described bypass is less, thereby is preferred.
As for the type of scale inhibitor, any kind all can use, as long as can prevent the calcium sulfate dirt precipitation.But from price and effectiveness aspect, preferably use polyphosphate such as Sodium hexametaphosphate 99 (SHMP), organic monomer as with ethylenediamine tetraacetic acid (EDTA) (EDTA) as representative, organic polymer such as polyacrylic acid or alginic acid.
About the scale inhibitor injection device, there is not particular restriction for pattern, as long as stable amount can be injected described feedwater, but preferably inject the suction side (low-tension side) of the topping-up pump of hyperfiltration membrane module, because can inject accurately and efficiently with surge pump or toothed gear pump.
In addition, though the present invention applicable to various types of water as water inlet 1 as river, lakes and marhshes water, underground water and trade effluent, preferably treatment seawater or highly spissated slightly salty are because can demonstrate its feature such as high-recovery and economic benefit.
Index one silt density index (SDI) (SDI value) of the impurity of indication water inlet preferably is controlled at 4 or lower.Using the SDI value is 4 or lower water, does not almost have the pollution of suspended substance attached to hyperfiltration film or reverse osmosis membrane surface, and described equipment can the stable manner prolonged operation.Note the concentration of small suspended substance in the described SDI value indication water, by (1-T
0/ T
15) * 100/15 expression, wherein T
0When carrying out pressure filtration with the microfiltration membrane of 0.45 μ m under 0.2MPa, representative filters first 500ml sample water required time, T
15Represent T under the same conditions
015 minutes another 500ml sample water required times of after-filtration of after-filtration.This value of water of basic no suspended substance is 0, and the maximum value of most of impure waters is 6.67.
Be used for will water inlet SDI value be controlled at 4 or the defecation method of lower clarifying plant 2 do not have particular restriction, but preferably adopt condensation sedimentation for example commonly used or condensation sand filtration processing, refining filtration or other filtration.More preferably filter,, can make stable operation, and can prolong the life-span of membrane element because can reduce the pollution to hyperfiltration membrane module and reverse osmosis membrane assembly such as suspended substance, microorganism with micro-filtration membrane module or hyperfiltration membrane assembly.Here, microfiltration membrane is narrow hole that 0.1 to 1 μ m is arranged, is used for infiltration water and dissolved constituent but removes the separatory membrane of suspended substance, particulate and microorganism (0.1 μ m or bigger).Ultra-filtration membrane is narrow hole that 0.01 to 0.1 μ m is arranged, be used for infiltration water and dissolved constituent but remove the separatory membrane of organic polymer, suspended substance, particulate, virus and microorganism (0.1 μ m or bigger).Among the present invention, described microfiltration membrane or ultra-filtration membrane can be made by any material, can be any type of, as long as described film has above-mentioned functions or narrow hole.Under arbitrary situation, the examples of material that can be used for described film comprises organic polymer films such as polyacrylonitrile, polysulfones, polyvinylidene difluoride (PVDF), polyethylene, polypropylene, polyethersulfone and rhodia polyimide, and ceramic membrane such as aluminum oxide, zirconium white and aluminum oxide silicon monoxide, its form can be tubular film such as tubular fibre, tubulose or one-piece construction or flat component such as volution or plate and frame.
In addition, except that the above-mentioned layout that adopts filter method, under the situation of using 200m or darker deep-sea water or fetching water as strainer with the submarine sand, do not need the filtration treatment device, this layout also is preferred.
Embodiment
Below in conjunction with following examples and Comparative Examples the preferred embodiments of the invention are described in more detail.
Embodiment 1-10 and Comparative Examples 1-5
Estimate the influence of hyperfiltration to the rate of recovery and working pressure.Be configured with the desalter shown in Figure 1 of the two-stage membrane module of arranged in series with hyperfiltration membrane module and reverse osmosis membrane assembly.
About the hyperfiltration membrane module, make 4 inches of diameters, membrane area 7.0m
2Element, 4 to 6 such elements are placed on form membrane module in the pressurized vessel.The performance of used hyperfiltration membrane module is as follows: with the rate of recovery of the working pressure of 1.5MPa and 13% filter down at 25 ℃ that pH6.5, total salt concentration are about 3.5%, under the condition of the seawater of the about 350mg/l of calcium ion concn, the about 2100mg/l of sulfate ion concentration, total ratio of desalinization about 62%, calcium ion decreasing ratio about 53%, the sulfate ion decreasing ratio is about 97%, the about 4.9m of the output of water
3/ d.About reverse osmosis membrane assembly, make 4 inches of diameters, membrane area 7.0m in the mode identical with the hyperfiltration film
2Element, 6 to 8 such elements are placed on form membrane module in the pressurized vessel.The performance of used reverse osmosis membrane assembly is as follows: under the condition of 25 ℃ of seawater that filter pH6.5, total salt concentration about 3.5% down, total ratio of desalinization is 99.7%, the about 5.0m of the output of water with the rate of recovery of the working pressure of 5.5MPa and 13%
3/ d.In this desalter, infeed with the ultra-filtration membrane device SDI value is transferred to seawater in 2.5 to 3.5 scopes, the total salt concentration of described seawater about 3.5%, the about 350mg/l of calcium ion concn, the about 2100mg/l of sulfate ion concentration.Handle described seawater with described hyperfiltration membrane module unit, water former state after the filtration use or with the bypass sea water mixing, what thereby preparation had salt concn shown in the table 1 and a calcium ion concn will supply with the unitary water of described reverse osmosis membrane assembly, and described water is infeeded in the described reverse osmosis membrane assembly under the operational condition shown in the embodiment 1-10 in table 1.On the other hand, as a comparison case, use and the identical desalter of these embodiment, shown in Comparative Examples 1-5 in the table 1, under the operational condition outside the scope of the invention, carry out sea water desaltination, operate 24 hours postevaluation performances.
The result, the step of these embodiment can be operated described reverse osmosis membrane assembly under the lower working pressure and the higher rate of recovery, obtain the fresh water of good quality, causing rate of recovery deficiency, needing higher working pressure to obtain fresh water or can only be with the problems such as rate of recovery operation lower than the embodiment under the identical reverse osmosis membrane working pressure under the rate of recovery identical with embodiment because of the reverse osmosis membrane surface scale then appears in Comparative Examples.
In addition, analyze the calcium ion concn of the condensed water of the condensed water of hyperfiltration film and reverse osmosis membrane with the ICP emission spectrometry method of JIS K0101 regulation, with the ion chromatography analysis sulfate ion concentration of JIS K0101 regulation.The concentration of analyzing the condensed water that shows embodiment 1-10 and Comparative Examples 1-3 is lower than the precipitation boundary of calcium sulfate dirt, prove and do not have the dirt precipitation in the described condensed water, but do not carrying out the hyperfiltration processing and under high-recovery, carrying out in the layout (Comparative Examples 5) of reverse-osmosis treated, the calcium ion concn of reverse osmosis membrane assembly and sulfate ion concentration meet or exceed described dirt precipitation boundary simultaneously, and proving has the calcium sulfate dirt precipitation in the described condensed water.
Embodiment 11-13
Estimate the effect of scale inhibitor with the hyperfiltration film of high decalcification rate.Adopt the equipment identical with embodiment 1, but the performance of used hyperfiltration membrane module is as follows: with the rate of recovery of the working pressure of 1.5MPa and 13% filter down at 25 ℃ that pH6.5, total salt concentration are about 3.5%, under the condition of the seawater of the about 350mg/l of calcium ion concn, the about 2100mg/l of sulfate ion concentration, total ratio of desalinization about 65%, the calcium ion decreasing ratio is higher, be about 72%, the sulfate ion decreasing ratio is about 99%, the about 4.8m of the output of water
3/ d.In table 1 illustrated embodiment, in the water inlet of supplying with described hyperfiltration membrane module, add Sodium hexametaphosphate 99 as scale inhibitor with ratio shown in the embodiment 11-13, under condition shown in the table 1, carry out desalination.As a result, among the embodiment 11-13, because described scale inhibitor although calcium ion concn is very high in the condensed water of described hyperfiltration membrane module, fouling does not take place yet.Therefore, reverse osmosis membrane assembly is also operated with high-recovery when carrying out the hyperfiltration processing with high-recovery, and does not produce dirt.
Estimate the effect that hyperfiltration assembly unit and reverse osmosis module unit adopt multistage layout respectively.Use 8 hyperfiltration membrane elements identical with embodiment 1, two groups (every group of three elements) are placed on the hyperfiltration membrane module that forms in the pressurized vessel separately separately and are used as the first substate assembly, one group (two elements) is placed on and forms the hyperfiltration membrane module in the pressurized vessel as single second stage assembly, thereby assembling hyperfiltration membrane module unit, use 12 reverse-osmosis membrane elements identical with embodiment 1, three groups (every group of four elements) are placed in the pressurized vessel separately and form reverse osmosis membrane assembly, wherein two groups as separately the first substate assemblies, one group as the second substate assembly, thereby be assembled into the reverse osmosis membrane assembly unit, assemble desalter shown in Figure 2.
In this desalter, infeed with the condensation sand filtering device SDI value is transferred to seawater in 3 to 4 scopes, the total salt concentration of described seawater about 3.5%, the about 350mg/l of calcium ion concn, the about 2100mg/l of sulfate ion concentration.70m wherein
3/ d (for flooding quantity 70%) infeed described hyperfiltration membrane module unit, under the working pressure of 25 ℃ and 2.5MPa, handle through hyperfiltration, described hyperfiltration membrane module unit produces 57.7m with 82.4% the rate of recovery
3The infiltration water of/d, the total salt concentration of described infiltration water are 2.07%, calcium ion concn is that 239mg/l, sulfate ion concentration are 133mg/l.Then, the infiltration water that is obtained by described hyperfiltration membrane module unit is mixed with remaining 30% water inlet in static mixer, produce 87.7m
3/ d, total salt concentration are 2.56%, calcium ion concn is that 276mg/l, sulfate ion concentration are the water of 805mg/l.
Then, the seawater after the described adjusting is infeeded the reverse osmosis membrane assembly unit, all through reverse osmosis isolation, the rate of recovery with 80% obtains 70m under the working pressure of 9.0MPa
3The product water of/d, it is that total salt concentration as the water quality of infiltration water is the fresh water of 226mg/l.At this moment, by the 100m that infeeds desalter
3/ d the calculating of intaking, the total yield of described reverse osmosis membrane assembly infiltration water is 70%.
Operate continuously is about 3 months under the aforesaid operations condition, and is almost identical when beginning to operate from the unitary fresh-water flow of reverse osmosis membrane assembly, water quality, the rate of recovery, working pressure etc., promptly do not observe performance degradation.
Embodiment 15
Under the situation that increases first step enriched material pressure, estimate the effect of the multistage layout in reverse osmosis module unit.Assemble desalter in the mode identical, but in the condensed water passage of first step reverse osmosis membrane assembly, centrifugal blower-pump is set, thereby form reverse osmosis membrane assembly shown in Figure 3 with embodiment 14.
In this desalter, infeed with the ultra-filtration membrane device SDI value is transferred to 1.5 or lower seawater, the total salt concentration of described seawater about 3.5%, the about 350mg/l of calcium ion concn, the about 2100mg/l of sulfate ion concentration.Under the condition identical, carry out hyperfiltration and handle, mixes, thereby identical water inlet is with supply reverse osmosis membrane assembly unit among preparation composition and amount and the embodiment 14 with the bypass water inlet with embodiment 14.
Then, whole seawater after the described adjusting are infeeded the reverse osmosis membrane assembly unit, and through reverse osmosis isolation, the working pressure of first step reverse osmosis membrane assembly is 6.5MPa, the working pressure of second stage reverse osmosis membrane assembly is 9.0MPa, thereby obtains 66m with 75% the rate of recovery
3The product water of/d, it is that total salt concentration as the water quality of infiltration water is the fresh water of 174mg/l.At this moment, by the 100m that infeeds desalter
3/ d the calculating of intaking, the total yield of described reverse osmosis membrane assembly infiltration water is 66%.
Operate continuously is about 3 months under the aforesaid operations condition, and is almost identical when beginning to operate from the unitary fresh-water flow of reverse osmosis membrane assembly, water quality, the rate of recovery, working pressure etc., promptly do not observe performance degradation.
Effect of the present invention
According to the present invention, can suppress because of suspension and calcium dirt obstruction reverse osmosis membrane, because total salt concentration falls Low, described reverse osmosis membrane can operate by high-recovery, for example can be higher in the rate of recovery, lower-cost Produce fresh water in stable mode by seawater in the situation.
Table 1
| Sequence number | Water inlet (m3/d) | Bypass ratio (%) | The hyperfiltration membrane module unit | |||||||||||
| Feedwater | Number of elements | Infiltration water (after 24 hours) | Condensed water (after 24 hours) | |||||||||||
| Flow (m3/d) | Pressure (MPa) | Scale preventative (ml/l) | Flow (m3/d) | The rate of recovery (%) | Salinity (mg/l) | Ca 2+ (mg/l) | Ca 2+ (mg/l) | SO 4 2- (mg/l) | Have or not dirt | |||||
| Embodiment | 1 | 40 | 0 | 40.0 | 2.5 | - | 6 | 35.4 | 88.6 | 22393 | 254 | 1092 | 17190 | Do not have |
| 2 | 40 | 0 | 40.0 | 2.5 | - | 6 | 35.4 | 88.6 | 22393 | 254 | 1092 | 17190 | Do not have | |
| 3 | 40 | 10 | 36.0 | 2.0 | - | 6 | 29.8 | 82.8 | 20741 | 239 | 884 | 11565 | Do not have | |
| 4 | 40 | 10 | 36.0 | 2.0 | - | 6 | 29.8 | 82.8 | 20741 | 239 | 884 | 11565 | Do not have | |
| 5 | 45 | 20 | 36.0 | 2.5 | - | 5 | 30.6 | 85.1 | 21397 | 245 | 850 | 13300 | Do not have | |
| 6 | 50 | 30 | 35.0 | 2.5 | - | 5 | 30.3 | 86.5 | 21796 | 249 | 998 | 14610 | Do not have | |
| 7 | 55 | 40 | 33.0 | 2.0 | - | 5 | 25.8 | 78.1 | 19782 | 230 | 779 | 9161 | Do not have | |
| 8 | 70 | 50 | 35.0 | 2.5 | - | 5 | 30.3 | 86.5 | 21796 | 249 | 998 | 14610 | Do not have | |
| 9 | 75 | 60 | 30.0 | 2.5 | - | 4 | 25.0 | 83.5 | 21067 | 242 | 897 | 12023 | Do not have | |
| 10 | 100 | 70 | 30.0 | 2.5 | - | 4 | 25.0 | 83.5 | 21067 | 242 | 897 | 12023 | Do not have | |
| 11 | 40 | 0 | 40.0 | 2.5 | 1.0 | 6 | 34.7 | 86.8 | 20534 | 176 | 1492 | 15660 | Do not have | |
| 12 | 50 | 30 | 35.0 | 2.0 | 0.5 | 6 | 28.9 | 82.5 | 19383 | 165 | 1222 | 11843 | Do not have | |
| 13 | 100 | 70 | 30.0 | 2.5 | 1.5 | 5 | 27.4 | 91.4 | 22340 | 195 | 2001 | 23937 | Do not have | |
| Comparative Examples | 1 | 150 | 80 | 30.0 | 2.5 | - | 4 | 25.0 | 83.5 | 21067 | 242 | 897 | 12023 | Do not have |
| 2 | 150 | 80 | 30.0 | 2.5 | - | 4 | 25.0 | 83.5 | 21067 | 242 | 897 | 12023 | Do not have | |
| 3 | 150 | 86 | 22.5 | 2.0 | - | 4 | 19.5 | 86.7 | 21974 | 250 | 998 | 14772 | Do not have | |
| 4 | 40 | 100 | - | - | - | - | - | - | - | - | - | - | - | |
| 5 | 40 | 100 | - | - | - | - | - | - | - | - | - | - | - | |
Water inlet: salinity 34987mg/l, Ca2+Concentration 350mg/l, SO4 2-Concentration 2100mg/l,
25 ℃ of temperature, pH6.5
Hyperfiltration membrane component performance: salt rejection rate 62%, Ca2+Removal efficiency 53%, SO4 2-Removal efficiency 97%, fresh water yield 4.9m3/d
[under the pressure of above-mentioned flow condition and 1.5MPa, assessing]
Table 1 (continuing)
| The reverse osmosis membrane assembly unit | Overall recovery (%) | ||||||||||
| Feedwater (hyperfiltration+bypass water inlet) | Number of elements | Infiltration water (after 24 hours) | Condensed water (after 24 hours) | ||||||||
| Flow (m3/d) | Salinity (mg/1) | Ca 2+ (mg/1) | Pressure (MPa) | Flow (m3/d) | The rate of recovery (%) | Salinity (mg/1) | Ca 2+ (mg/1) | SO 4 2- (mg/1) | Have or not dirt | ||
| 35.4 | 22393 | 254 | 8.5 | 6 | 28.0 | 79.0 | 269 | 1191 | 731 | Do not have | 70.0 |
| 35.4 | 22393 | 254 | 9.2 | 6 | 29.5 | 83.3 | 301 | 1492 | 903 | Do not have | 73.8 |
| 33.8 | 22428 | 252 | 8.4 | 6 | 26.7 | 79.0 | 283 | 1184 | 1732 | Do not have | 66.8 |
| 33.8 | 22428 | 252 | 9.2 | 6 | 27.8 | 82.2 | 312 | 1400 | 2030 | Do not have | 69.5 |
| 39.6 | 24485 | 269 | 8.7 | 6 | 30.5 | 77.0 | 250 | 1160 | 2547 | Do not have | 67.8 |
| 45.3 | 26171 | 282 | 9.0 | 6 | 34.4 | 75.9 | 234 | 1176 | 3306 | Do not have | 69.0 |
| 47.8 | 26789 | 285 | 8.7 | 8 | 36.3 | 75.9 | 289 | 1188 | 4303 | Do not have | 66.0 |
| 32.7 | 28876 | 303 | 9.0 | 6 | 24.5 | 74.9 | 361 | 1190 | 4765 | Do not have | 70.0 |
| 35.0 | 30018 | 311 | 9.0 | 6 | 25.9 | 74.0 | 343 | 1197 | 5378 | Do not have | 69.1 |
| 47.5 | 31329 | 322 | 9.0 | 8 | 34.7 | 73.1 | 329 | 1185 | 5852 | Do not have | 69.4 |
| 34.7 | 20534 | 176 | 9.0 | 6 | 28.5 | 82.1 | 290 | 980 | 221 | Do not have | 71.3 |
| 43.9 | 24722 | 228 | 9.0 | 8 | 34.9 | 79.5 | 333 | 1142 | 3708 | Do not have | 69.8 |
| 48.7 | 31436 | 306 | 9.2 | 8 | 35.6 | 73.1 | 323 | 1178 | 5854 | Do not have | 71.2 |
| 48.3 | 32594 | 331 | 10.1 | 6 | 34.8 | 72.0 | 272 | 1183 | 6290 | Do not have | 69.6 |
| 48.3 | 32594 | 331 | 9.0 | 6 | 31.9 | 66.0 | 234 | 973 | 5172 | Do not have | 63.8 |
| 49.0 | 33272 | 337 | 9.0 | 6 | 31.3 | 63.9 | 233 | 936 | 5110 | Do not have | 62.7 |
| 40 0 | 34990 | 350 | 9.0 | 6 | 24.5 | 61.3 | 307 | 901 | 5414 | Do not have | 61.3 |
| 40.0 | 34990 | 350 | 11.5 | 6 | 27.6 | 69.0 | 307 | 1241 | 7442 | Have | 69.0 |
Reverse-osmosis membrane element performance: salt rejection rate 99.7%, fresh water yield 5.0m3/d
[under the pressure of above-mentioned flow condition and 5.5MPa, assessing]
Scale preventative: calgon
Claims (26)
1. one kind makes the method for water desalination in being provided with membrane module unit separately multistage, thereby wherein supplies with second stage membrane module unit by its infiltration water that obtains desalination from the infiltration water of first step membrane module unit, and described method comprises:
The first step, handling total salt concentration is that 3.0-4.8 weight % and calcium ion concn are the water inlet of 200～500mg/l, in the first step, handle at least a portion water inlet and obtain infiltration water with first step membrane module unit, described infiltration water is mixed with other water inlet, thus make the total salt concentration of described the first step treated water be 55-90%, the calcium ion concn of described water inlet be described water inlet 95% or lower; With
In second step, described the first step treated water is supplied with second stage membrane module unit, thereby obtain the water of desalination.
2. the process of claim 1 wherein that the sulfate ion concentration of described water inlet is 1500～3500mg/l, by the described the first step with sulfate ion concentration transfer to described water inlet 80% or lower.
3. the process of claim 1 wherein that 30～100% usefulness first step membrane module unit of described water inlet handle, mix with untreated water inlet then, supply with described second stage membrane module unit.
4. the method for claim 3,35 to 95% usefulness first step membrane module unit of wherein said water inlet are handled, and mix with untreated water inlet then, supply with described second stage membrane module unit.
5. the method for claim 4,40 to 90% usefulness first step membrane module unit of wherein said water inlet are handled, and mix with untreated water inlet then, supply with described second stage membrane module unit.
6. the method for claim 1, described method carry out representing that with the percentage that accounts for total supply amount of seepage is in 65% to 95% scope so that provide infiltration water and condensed water by the water of supplying with first step membrane module unit like this.
7. the method for claim 6, the percentage of wherein said amount of seepage is in 75% to 90% scope.
8. the method for claim 1, described method carry out representing that with the percentage that accounts for total supply amount of seepage is in 70% to 85% scope so that provide infiltration water and condensed water by the water of supplying with second stage membrane module unit like this.
9. the method for claim 1, described method is carried out like this so that represent to be that so-called total yield is in 60% to 80% scope from the infiltration water total amount of second stage membrane module unit with the percentage that accounts for flooding quantity.
10. the method for claim 9, wherein said amount of seepage percentage from second stage membrane module unit is in 65% to 75% scope.
11. the process of claim 1 wherein that described first step membrane module unit uses the hyperfiltration film unit, described second stage membrane module unit is used reverse osmosis membrane unit.
12. the method for claim 11, wherein said first step hyperfiltration membrane module unit has respectively first and second membrane modules in first and second substates of the described first step at least, each membrane module all provides infiltration water and condensed water, wherein supplies with the second substate hyperfiltration membrane module from the condensed water of the first substate hyperfiltration membrane module.
13. the method for claim 11, reverse osmosis membrane assembly unit, the wherein said second stage has respectively first and second membrane modules in described partial first and second substates at least, each membrane module all provides infiltration water and condensed water, wherein supplies with the second substate reverse osmosis membrane assembly from the condensed water of the first substate reverse osmosis membrane assembly.
14. the method for claim 13 wherein makes the pressure raising from the condensed water of the first substate reverse osmosis membrane assembly, then described condensed water is supplied with the second substate reverse osmosis membrane assembly to obtain the water of desalination.
15. the method for claim 14, wherein in being provided with a plurality of substates of reverse osmosis membrane assembly, the pass between the working pressure P (n) of the first substate reverse osmosis membrane assembly and the working pressure P (n+1) of the second substate reverse osmosis membrane assembly ties up in the given scope of following formula:
1.15≤P(n+1)/P(n)≤1.8。
16. the method for claim 11 was wherein injected scale inhibitor in the water of supplying with described hyperfiltration membrane module unit before carrying out hyperfiltration.
17. the process of claim 1 wherein that described water inlet is the filtered water of crossing with microfiltration membrane or ultrafiltration membrane treatment.
18. a desalter comprises:
Respectively at least the first and second membrane module unit of first and second grades of the successive that is used for water infiltration,
As described first film unit of the first step, the hyperfiltration membrane module unit has membrane module and by the output channel of the water of its infiltration,
As partial described second film unit, the reverse osmosis membrane assembly unit is arranged in the output channel of water of infiltration of described hyperfiltration membrane module unit; With
Thereby be used to make the part water inlet of supplying with the described hyperfiltration membrane module unit of pointing to described output channel to turn to the device of walking around described membrane module.
19. being useful on, the desalter of claim 18, the output channel of wherein said hyperfiltration membrane module unit make the water blended device of the described part water inlet that turns in the hyperfiltration membrane module unit infiltration of the upstream, reverse osmosis membrane assembly unit, the second stage and the first step.
20. the desalter of claim 18, wherein said first step membrane module unit is the hyperfiltration membrane module unit that at least one first membrane module in first and second substates of successive separately of the described first step and at least one second membrane module are arranged, each membrane module can both provide infiltration water and condensed water, and wherein the second substate hyperfiltration membrane module is arranged in the condensed water output channel of the first substate hyperfiltration membrane module.
21. the desalter of claim 20, the pass between total film surface-area S1 (n) of wherein said or each first substate hyperfiltration membrane module and the total film surface-area S1 (n+1) of described or each second substate hyperfiltration membrane module ties up in the given scope of following formula:
1.5≤S1(n)/S1(n+1)≤5。
22. the desalter of claim 20, wherein said second stage membrane module unit is the reverse osmosis membrane assembly unit that at least one first membrane module in described partial first and second substates of successive separately and at least one second membrane module are arranged, each membrane module can both provide infiltration water and condensed water, and wherein the second substate reverse osmosis membrane assembly is arranged in the condensed water output channel of the first substate reverse osmosis membrane assembly.
23. the desalter of claim 22, the pass between total film surface-area S2 (n) of wherein said or each first substate reverse osmosis membrane assembly and the total film surface-area S2 (n+1) of described or each second substate reverse osmosis membrane assembly ties up in the given scope of following formula:
1.67≤S2(n)/S2(n+1)≤2.5。
24. the desalter of claim 22, the supercharging device that wherein is used for improving condensed water pressure are arranged in the condensed water output channel of at least one first reverse osmosis membrane assembly of described partial first substate.
25. the desalter of claim 18, wherein the scale inhibitor injection device is arranged in the water entry of described hyperfiltration membrane module unit upstream.
26. the desalter of claim 18, wherein micro-filtration membrane module unit or hyperfiltration membrane assembly unit are arranged in the water entry of described hyperfiltration membrane module unit upstream.
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| CN102791637A (en) * | 2010-03-15 | 2012-11-21 | 东丽株式会社 | Method for producing fresh water |
| CN102985373A (en) * | 2010-08-17 | 2013-03-20 | 东丽株式会社 | Fresh water producing apparatus and method for operating same |
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