CN1011577B - Concentration of solids in suspension - Google Patents

Abstract

The present invention relates to a concentrator (10) used for concentrating superfine solids in a suspension, which is provided with a sleeve pipe (11), wherein the inside of the sleeve pipe is provided with a bundle of microporous fibers (12). A pressurized suspension enters an inlet (15) and passes through the outer walls of the fibers (12), clear liquid flows out from hollow cavities of the fibers (12) through an outlet (16), and condensed feed liquid is discharged through an outlet (17). Solids remained in the sleeve pipe are removed by that firstly pressurizing liquid is used for expanding all holes of the fibers, all residual solids are washed out, then gas with sufficient pressure is used for ensuring that the gas can pass through the larger holes of the fibers, and solids in the sleeve pipe (11) are removed and sent to an external collection point through the outlet (17).

Description

Concentration of solids in suspension

The present invention relates to concentrate the micro-solid in the suspension material liquid.

The problem of micro-solid is to replenish mutually with the problem that makes suspension revert to clear liquid in the concentrated suspension liquid.

The clear liquid producer regards all visible traces of solids as refuse usually.The method that adopts often comprises adding flocculant and filter aid, and this can pollution solid.The content of solid has the tendency of step-down, this just impels the employing certain methods to move away clear liquid from the suspension material liquid jar of continuous charging, solids content increases in jar, after presenting some injurious effects, material row in the suspension material liquid jar need be discharged in some other equipment and go.Solid gather the production of must slowing down constantly, and adopt the equipment of some continuous blow-down thickened solid, productivity ratio is improved.

On the contrary, fine powdery solid manufacturing industry often is food, exploitation or process industry, that is, wish to obtain solid, and liquid preferably recycles.Also have, solid is having certain specification requirement aspect granularity and the purity, often needs further processing and mostly needs to obtain highly filled concentrate.Certainly, filter aid will polluted product.

R.Bertera, H.Steven and M.Metcalfe to needing in this class aspect the cross flow one micro porous filtration, have done up-to-date going through at the The Chemical in June, 1984 Engineer 10-14 page or leaf.

Shown in Figure 8 as above-mentioned quoted passage, if under constant density cross flow one (laterally filtering) pattern, processing contains the feed liquid of fine inorganic fillers, go backwash with the clear liquid that passes filter membrane, even up-to-date 1984 commodity anka-Man Bulanna Co., Ltd (Enka Membrana A.G.) filter assemblies, also can stop up and make the clear liquid flux constantly to descend rapidly.

Also can overcome serious obstruction of solid economically without filter aid is the most pressing problem.This class blockage problem is well-known already, and has put down in writing some on the technology and replace clear liquid to go backwash with gas, and clear liquid is counter to flow to the trial of going in the suspension material liquid to avoid.Therefore, the patent publication No. 53(1978 of Japanese unexamined)-108882 indicate:

" owing to oppositely come cleaning filter membranes without filtrate among the present invention, the critical defect of prior art method (being that filtrate is returned original liquid in fact) is overcome, and is obviously favourable to industry.”

Gas passes the filter membrane back flush, and to the filter in atomic hole, it is inapplicable resembling reverse osmosis membrane and ultrafilter, because overcome the required pressure of surface tension, and the hollow fibre film strength commonly used of doing this purposes that surpasses far away; Wettable liquid can pass through this film, but gas is not all right.Each bubble that passes this class film all shows have pin-hole like defects on film.Therefore, this invention is not suitable for reverse osmosis membrane or real ultrafilter.

This invention is relevant with millipore filter, and this filter has the hole bigger than ultrafilter, and its scope is 0.001 to 10 micron.Usually, the distribution in bigger hole should be able to make clear liquid not have any visible turbidity.Turbidity not only relates to the size of particle, and it draws and obey this law by the optical laws of knowing.

Originally millipore filter stops up rapidly, be owing to particle that their are handled is not to be suspended state by Brownian movement or diffusion, but these particles is filled out in the hole similar to its granule size in the mode of stifled sieve aperture.

A kind of prior art that addresses this problem is to allow hydrophilic millipore filter work under the cross flow one pattern, passes filter membrane with clear liquid and comes backwash.High cross flow one rate request suspension material liquid is in bigger fiber outer surface and is in a ratio of less inner filtration surface, chamber on one side.Like this, backwash pressure just must be limited, to avoid the fiber that crushes.Less filter area has reduced output, so need not this means solve blockage problem usually.

At Japanese publication 53(1978) disclosed another prior art in-108882, method is wherein made a kind of hollow fiber bundle that resembles a branch of " candle light " the sort of shape of scattering that has with a kind of hydrophilic " polyvinyl alcohol (PVA) " fiber, so that make the fibre bundle twisting when the inner chamber backwash of carrying out (one minute) for a long time with air.This class " candle light " shape filter of narrating in this part Japanese description more resembles the filter of end sealing, and not too resembles cross flow one thimble tube and cast filter, and these filters are hollow jar of shape of elongation in the sealing of one end.

Point out in the example of above-mentioned Japanese description and the individual event claim, disclosed invention is to rely on air to flow to blind end vibration or the vibrations that cavity causes fiber, thereby 50/1000000ths tiny iron colloid of suspension material liquid in the pressurization suspension material liquid jar can be separated.Japanese description indicates:

" (depend merely on cavity gas) in this way, the fine particle of deposition can be removed after introducing compressed air fully.”

We experiment showed, that this is because " iron colloid " is thicker than the hole, is blocked in fiber surface fully.Have other obstruction material such as rough sucrose mix juice or starch wastewaters of wider size distribution particle scope, removing will be much more difficult.

" candle light " shape device of 2,120,952 pairs of above-mentioned hydrophilic " polyvinyl alcohol (PVA) high polymer " porous hollow fibers of discovery british patent specification is developed.The test suspension of narrating in this part specification only contains 5/1000000ths iron oxide, and average grain diameter is 0.6 micron, and particle diameter guarantees too to clean to the relation in aperture and is not difficult to carry out.Loosely is tied up fiber and with they pack into sleeves of opening, stoped the twisting of fibre bundle to a certain extent, so just avoided referring in the entanglement of fiber and the fracture (this break at above-mentioned Japanese publication number 53(1978)-108882), but the gas backwash need continue 5 minutes.

Should be pointed out that relevant prior art only uses one type fiber, be named as vinal, its person's character is hydrophilic.But, if employing is nonwetting property iron colloid and hydrophobic fiber, resembling polypropylene fibre, the gas backwash will cause the obstruction in hole.

This gas can be predicted by theory after being blocked in and having done " bubble point pressure " mensuration.This class gas obstruction is serious in practicality.As far as we know, prior art was not revealed the fiber that comes down to hydrophobic with the gas backwash, and once pointed out to run into the situation that gas stops up after the gas backwash extended to 5 minutes from 1 minute.

Prior art comprise other one piece with several incoherent gas backwashes reports of " jar in cured candle " type, but what adopted is heat cured rather than thermoplastic high polymer, so that make a kind of chemically stable hydrophilic filter.

This report is included in Russian Patent 955, among 986, this patent relates to big jar of (250 millimeters long, 70 millimeters bores and 25 millimeters wall thickness) use, this class jar is to make with a kind of undocumented technology with the hard microballoon of polishing, the microballoon material is thermosetting plastics phenol/formaldehyde, resorcin/formaldehyde, catechol/formaldehyde or melamine/formaldehyde.From 0.5 to 5 micron of microsphere diameter scope has 0.1 to 1.6 micron hole.These holes are infiltrated 0.3 to 0.5 millimeter with fine inorganic particulate matter.Though satisfied the purposes of Soviet Union's description on the surface, this equipment and cross flow one device and minimum clear liquid backwash are different in kinds.

Although the prior art millipore filter can be reclaimed micro-solid from suspension, their operation does not reach industrial success in this as yet.The reason why this technology does not obtain to generally acknowledge is exactly: because the variation in aperture, the variation of both character of solid and filter medium and physical characteristic, and need remove the hole support greatly and hold back solid, make effectively and apace micro-solid to be separated from filter medium to become complicated.

The prior art millipore filter is used to separate another reason that micro-solid do not reach industrial success as yet, used fiber is too poor to the corrosion resistance of concentrated hydrochloric acid and NaOH, these acid, alkali often are used to remove the natural products in the filter, the latter is present in the raw material, has stopped up the fiber of filter.

In addition, the hollow fibre of prior art millipore filter can be by hypochlorite, chlorine and hydrogen peroxide destroy rapidly, and these materials are regularly to be used for sterilizing and filter rinsed.

Another shortcoming of prior art is, before backwash cycles is not finished, can not carry out removing the operation of tamper from filter container, and this has just increased the downtime of filter.

The purpose of this invention is to provide and a kind ofly come concentrated suspension liquid and discharge to hold back solid, guarantee to remove rapidly the method for holding back solid with counter-flow pattern with the cross flow one clastotype.Separation in this method and discharge pattern be repetitive cycling for a long time.

Further purpose of the present invention provides the method for the solid in a kind of concentrated suspension liquid, this method can be with a kind of elasticity microporous hollow fiber, this fiber is not only stood and is repeated support greatly, this support is greatly often to take place in the cycling pattern, also stands the chemical environment under the industrial filtercondition.

According to the present invention, the method for solid in a kind of concentrated suspension liquid is provided, the step of this method comprises:

(I) is added to suspension on the outer surface of elasticity microporous hollow fiber of housing or casing, makes:

(a) part suspension becomes clear liquid and flows out by fibre wall from fiber core,

(b) at least one part solid is trapped on the fiber or in the fiber, or on the contrary in housing, does not remove from housing together with residual liquid and be trapped solid,

(II) discharges the solid of holding back from housing, apply by fiber core:

(a) fluid under pressure makes it pass through all basically holes, thereby all basically holes are all supportted greatly, holds back solid to wash out, then feed,

(b) gas-pressurized makes it support big these holes by bigger hole, removing any solid of holding back in these holes, and the outer wall of purge fiber and enclosure interior, all solids is removed in housing, transfer to the collected outside point.

As a kind of form of invention, using gas-pressurized is to be used for whole length of backwash fiber in the incipient stage, and its method is under the pressure that is lower than the fibre wall bubble point pressure, with all cavity liquid of gas displacement.Use incompressible relatively reinforced liquid sealing housing then, when captive gas pressure was elevated to above bubble point pressure, gas can not flow through fibre wall.Remove the liquid sealing then, allow captive gas pass through fibre wall and escape equably basically,, so just reduced near the situation in the hole of constantly preferential flushing gas inlet even also like this from cavity inlet farthest.

The repetitive cycling of preferably utilizing solid accumulation and solid to discharge makes the method for invention be undertaken by continuous process.Can estimate that in desirable fiber pressurized fluid is known from experience by all holes, yet in fact has some holes to have thinner wall, wall can be crushed and make these hole plugs.

Solid is discharged after the step, postpone the quite a while possibly, recover the step that suspension material liquid flows through fiber again, so that the hole of expansion can return to their original aperture, so the particle of crossing coarsegrain in the suspension material liquid just can not enter or the hole by having enlarged.

In some cases, recovering flowing of feed liquid can be by the delay that is used for of gas itself, as long as the pressure of gas is higher than the pressure of suspension material liquid.Since discharge step when finishing gas pressure descend, the hole of fiber will begin to recover, and gas pressure drop to be lower than feed pressure before, just returned to their original aperture, so but the recovered part feed liquid flows through fibre wall.

If be ready, can control from the processed suspension material liquid of housing or casing outflow with valving, act on feeding liquid to produce counter-pressure, and this class valving can also be used for fluid under pressure and gas retrograde flow moving during to the control of suspension material liquid inlet.

According to invention on the other hand, provide a kind of inspissator, be used for reclaiming the micro-solid of suspension material liquid, this inspissator comprises:

(I) housing;

Flexible in a large number, hollow in (II) housing, the microporous polymer fibres;

(III) is to the device of fiber outside supplied with pressurized suspension material liquid;

(IV) device of sucking-off clear liquid in the fiber core,

(V) is earlier behind the liquid gas being sent into fiber core under pressure, to realize penetrating the device that filter membrane cleans fiber, the pressure of liquid will be enough to support all basically holes of big fiber, the pressure of gas also want sufficient to guarantee gas can by fiber than macropore, to remove any solid of its trapped inside, and the outer wall of purge fiber and enclosure interior, any solid is removed in housing, transfer to the collected outside point.

At one preferably in the mode of the present invention, inspissator also comprises with behind the gas-pressurized displacement fiber intracavity liquid, relative incompressible liquid is sealed in device in the housing, and therefore, gas just can be trapped in the chamber under the pressure of the bubble point pressure that is higher than fibre wall; Comprise that also unexpected release gas makes its device by fibre wall equably basically.

The most handy thermal plasticity high polymer of fiber is made, such as:

Polypropylene, poly-4-methylpent-1-alkene, the copolymer of propylene, poly-difluoroethylene, polysulfones, polyphenylene sulfid, polyoxygenated penylene, phenoxy resin, polytetrafluoroethylene (PTFE) and poly--chlorotrifluoroethylene.

This fibrid low price, and have gratifying elasticity, counter-bending fracture property and aperture, this is applicable under all temps them.

Though the characteristic of processed suspension material liquid is depended in the selection of fiber, come in summary, should select fiber like this, so that:

(a) distribution in aperture can allow to remove minimum in the case, wishes the particle removed, still,

(b) air can be passed through in some holes of fiber, and the diameter in all holes is below 10 microns, and

(c) cleaning solution of fiber anti-strong acid of energy or highly basic, and can tolerate heating or chemical disinfection repeatedly, also have

(d) in all holes with the clear liquid of certain volume (equaling total pore volume at least) when carrying out pressure wash, it is big that the character of fiber allows its hole to do the elasticity support, then be,

(e) clean supportting big hole with gas, its pressure is enough to the bigger hole of forced gas by the overwhelming majority, and solid is removed from fiber surface and housing wall, sends a transfer device to, so that the accumulation solid transfer outside system gatherer and

(f) elastic characteristic of fiber should make the bore in hole, can restore rapidly before returning to suspension material liquid after support is big, does not allow and is concentrated material and passes or hold back with regard to not having excessive hole like this.

If desired, but the above-mentioned flexible polymer fibres stable hydrophilic coating of anti-strong acid and highly basic on the coated also.The hydrophilic composite fiber that some are fit to comprises hydrophobic micropore thermoplastic elastic matrix and the cross-linked hydrophilic overcoat is arranged on hole wall, in our common unsettled International Patent Application PCT/AU84/00179 this is narrated.

Discharge in the process of step at gas, gas will be replaced those bubble point pressures and will be lower than feed liquid and/or clear liquid in the fiber holes of gas pressure.Under the situation of polypropylene and other hydrophobic fibers, these holes will become by air stops up shape, and still, this can be overcome with several ways, for example:

(a) before carrying out cross-flow operation or in the middle of operation, make hydrophobic fiber stand the plug flow of wetting agent, to reduce the surface tension of feed liquid to housing, make it be lower than 50(and be preferably 32 to 35) dynes per centimeter, at this moment the hole just becomes hydrophilic, and just heavily cover processing once at set intervals, when the trace thing of hydrophilic feed liquid is adsorbed on the hydrophobic fiber

(b) selected the initial of above-mentioned (a) method or after, handle hydrophobic fiber with enough feed pressure, dwindle remaining in the interior bubble of fiber holes and help them and from the hole, pass through, and keep the enough solubility of gas in feed liquid and/or penetrating fluid.

In order to be easier to understand this invention and to carry out practical operation easilier, existing accompanying drawing is done following with reference to explanation:

Fig. 1 is a hollow fibre cross flow one inspissator schematic diagram, concentrates or operator scheme for it shown in the figure,

Fig. 2 is the schematic diagram that is similar to Fig. 1, shown in inspissator be in the adverse current cleaning model,

Fig. 3 is the time dependent curve of clear liquid flux of hollow fibre cross flow one inspissator,

The back flow of gas purging system schematic diagram of Fig. 4 for making according to one embodiment of the invention,

Fig. 5 is the time dependent curve of clear liquid flux of the hollow fibre cross flow one inspissator of employing liquids and gases backwash, and,

Fig. 6 is the time dependent curve of clear liquid flux of only using the hollow fibre cross flow one inspissator of clear liquid backwash.

Comprise a filter cylinder housing 11 at the hollow fibre cross flow one inspissator 10 shown in Fig. 1 and Fig. 2, wherein settled a branch of hollow, porous, high polymer fibre 12. In this example, every fiber all is to make with polypropylene, 0.2 micron of average pore size, 200 microns of wall thickness, 200 microns of intracavity diameters. In bundle 12,3000 hollow fibres being arranged, no matter but the size of every fiber, or the quantity of the interior fiber of bundle, all can change by operation requirements.

With the end socket 13,14 that polyurethane is done, the end of fiber 12 is in position, but do not stop up their cavity, and the two ends of closure casing 11. The suspension material liquid that concentrates is pumped into housing 11 by suspension material liquid entrance 15 usefulness, passes through then the outer wall of hollow fibre 12. The wall that the partial suspended feed liquid is passed fiber 12 enters fiber lumen, and is logical as clear liquid Crossing cavity outlet 16 discharges.

Remaining suspension feed liquid and some floating things flow between fiber 12, and discharge housing 11 by outlet 17. Remaining floating thing then is adsorbed on the top or inner of fiber, or remains in the housing. Cavity entrance 18 was closed in inspissator shown in Figure 1 operating period always.

In order to remove residue, cavity outlet 16 is closed, allow clear liquid stop to flow out, then the clear liquid of pressurization is introduced cavitys along cavity entrance 18, and support big basically all hole, and with being that the clear liquid that equals whole pore volumes goes to clean them at least. After the clear liquid cleaning is finished, gas-pressurized enters along cavity entrance 18, pass fibre wall enters in suspension material liquid/concentrate stream along the chamber of fiber 12, cause strong bubbling, so just can remove all residues in the housing, these residues may be to accumulate on the outer wall of fiber, or when clear liquid cleans, in fiber holes, come out.

After (this is to long and thin fiber particularly suitable) unlatching cavity exports 16 1 limited periods in one embodiment of the invention, gas-pressurized enters from entrance 18, and gas passes through along the cavity of fiber 12, so just so that there is not the hole of gas permeation fiber at this one-phase. Close then housing entrance 15 and housing outlet 17 and make the housing seal that is full of liquid. Even gas pressure has raise much, surpassed the normal bubble point pressure point of fibre wall, gas still can not see through micro-pore wall, because the liquid in the housing is relatively incompressible. Like this, in fiber core, produced a high-pressure air source with regard to accumulation.

At this moment export 17 and open, so that gas sees through from the hole along whole length of every fiber. Originally, the vibration of bubbled gas is full and uniform, but the final because decline of pressing in the viscous at thin fiber place, makes at the bubbling away from an end place of cavity entrance 18 slack-off. Under the few cases, after having carried out above-mentioned pressurization, catching gas-operated, wish to allow gas pass through from cavity interface 16 and 18 two-way.

Be preferably in the time that delay phase is worked as after the purge of gas, the adding that recovers again suspension material liquid, with Just can be returned to original aperture by the big hole of gas support, the particle of crossing like this coarsegrain in the suspension material liquid just can not enter or pass through the hole of expansion.

What Fig. 3 represented is to the impact of clear liquid throughput rate about solid discharge in the narration of Fig. 2. When curve A represents not carry out the solid discharge, the decay in time of clear liquid flux, curve C then shows after each liquids and gases cooperate the discharge circulation, the recovery situation of clear liquid flux. Although the discharge of solid makes the clear liquid flux almost get back to initial value, after through one long period, can find that effective flux descends, discharge successively come what may also like this.

Clear liquid of the present invention/gas is discharged technology and can be provided in the system shown in Figure 4, and it can operate under the several modes. Concentrate under the pattern in cross flow one, pump 38 is extracted suspension material liquid out by the aspiration line 39 of pump from suspension material liquid tank 27, by inlet pressure valve 37, be transported to suspension material liquid entrance 29(suspension material liquid cut-off electromagnetic valve 41 be installed there), enter cross flow one inspissator 20.

Suspension material liquid leads on the hollow fibre surface in the cross flow one inspissator 20, and has some fluids to pass fiber to enter cavity and be transported to purified liquor outlet pipe 21. Clear liquid in the pipe 21 enters clear liquid and is detained tube 47, and this tube is handled by solenoid 47a, passes through clear liquid control valve 22(by solenoid 22a control again) and flow sensor 32, arrive the clear liquid collection and deposit a little.

The suspension material liquid that is concentrated in the cross flow one inspissator 20 flows through check (non-return) valve 35 and the solenoid operated words of bobbin seal valve 55(as being equipped with) enter pipeline 28, by being transported to threeway concentrate transfer valve 30 here, it is controlled by solenoid 30a. Valve 30 has exit passageway (a) and (b), leads to respectively suspension material liquid tank 27 and the concentrate collection is deposited a little. Under the pattern of concentrating, valve 30 is in position (a), and the suspension material liquid that therefore is concentrated enters tank 27 through backpressure valve 33.

By-passing valve 34 on the bypass pipe 40 is being controlled together with inlet pressure valve 37 and is being entered friendship The flow velocity of the moving inspissator 20 of distributary. Suspension material liquid tank 27 is equipped with suspension material liquid entrance 53 and flushing entrance 52.

Gas passes into pipeline 23 on request, and this pipeline comprises 24, one gas flow valves 25 of a gas-pressure controlling valve, by gas stop valve 26 and the check (non-return) valve 51 of solenoid 26a control.

Suspension inlet pressure, the suspension outlet pressure that is concentrated and clear liquid pressure are respectively by valve 37,33 and 22 controls or setting. During concentrating pattern, valve 26 cuts out, valve 55 be open and valve 30 place path (a). In this embodiment of the present invention, formerly follow with after the gas back flushing with clear liquid, when returning to the pattern of concentrating, be in order to remove in the given time the gas in the filter hole at inspissator housing 20 interior set pressures.

Monitored with flow sensor 32 from the liquid that valve 22 flows out, the parameter that detects is used as the input of cyclelog 31. Controller 31 with the clear liquid actual flow with preset flow value and time and compare to start and discharge circulation.

In this embodiment of the present invention, two criterions of independently determining the suitable time that inspissator 20 is discharged are arranged. Article one, criterion is delivery flow, in case it is lower than flow value predetermined and that set, controller 31 just starts discharges circulation. The second criterion is the time, and controller starts the discharge circulation under the interval at a fixed time. Fluid flow is descended not can very fast suspension material liquid, and the second criterion is more suitable.

In order to realize discharging, cyclelog 31 instruction solenoid 22a, 26a, 43a and 30a action, system is placed the discharge pattern, and its method is shut off valve 22 in turn, open valve 26, shut off valve 43 and change threeway and concentrate the exit passageway of liquid transfer valve 30 to path (b) therefore just can be discharged the delay clear liquid of continuous variable volume and gas discharge medium and the material under fiber removes from system.

So solid is discharged and just have been started by cyclelog 31, its instruction solenoid 26a Action, open gas trap 26, and start the solenoid 47a that clear liquid is detained tube 47, make the liquid in this equipment under the gas pressure effect that provides by valve 26, enter cavity, and pass across fiber by the direction opposite with normal operating, be trapped in any solid in the fiber holes in order to expand all holes and displacement.

Be detained tube 47 emptying after, cyclelog 31 continues to allow gas flow cross the bigger hole that valve 26 and pipeline 21 enter cavity and pass fiber concentrate and solid are gone out fiber, and the flushing enclosure interior. Finish when the gas discharge stage, solenoid 26a has closed valve 26.

For make the gas that bigger hole is passed through on the whole length of thin narrow fiber discharge more evenly, be preferably in be detained tube 47 emptying after, allow gas pass through cavity check (non-return) valve 46 and cavity stop valve 43(is opened it by cyclelog 31 instruction solenoid 43a). Then, controller 31 instruction solenoid 55a close bobbin seal valve 55, and instruction solenoid 41a closes reinforced stop valve 41, so that the gas pressure in the housing 20 rises to the maximum pressure that gas regulator 24 is set. By controller 31 instruction solenoid 55a, open housing seal valve 55 by predetermined gas efflux time then. Circulation timei to be discharged finishes, and cyclelog 31 instruction systems change the concentrated pattern such as above-mentioned step over to, only not with: be detained before tube 47 is full of by clear liquid, valve 22 cuts out always.

Processing to some suspension material liquid, special in the situation of high-pressure charging, during ejection preferably stop suspension material liquid and flow, make it when discharging beginning in this case controller 31 programs of enrolling, instruction solenoid 41a moves with shut off valve 41, open valve 41 when discharging end. This can be avoided concentrate to be diluted by suspension material liquid, and guarantees that the big hole of support recovers its aperture if having time, enters wherein with regard to the solid that prevented coarsegrain like this.

To some suspension material liquid, may wish with the form that classification concentrates residue to be collected. There are several selection schemes under the condition of the operator scheme that adopts concentration systems shown in Figure 4, to make this class more feasible and effective to the collection of trapped substance. For example, because some trapped substance at the film table Accumulation on the face is faster than other trapped substances, might in step successively a kind of trapped substance enrichment be become another kind of denseer concentrate stream, and the additional advantage of this scheme is to make total flux bigger. For realizing this enrichment, when processing a collection of suspension material liquid, the trapped substance that is concentrated in fiber surface can be transported to different destinations, perhaps to the continuous system of segmentation, each step is concentrated fluid collection in different containers.

Non-floating thing resemble the salt can start cycles of washing and remove from trapped substance. Under cleaning model, the suspension material liquid of suspension material liquid entrance 53 is closed, and clear water entrance 52 is opened, and comes the rinsing trapped substance with the flow the same with the clear liquid discharging flow. Scavenging period was determined by holdup time or the half-life of the system that the standard engineering computing technique is tried to achieve.

Referring now to following example the present invention is done further narration, wherein example 1 has adopted inspissator shown in Figure 4 to example 5 when operating, but does not have housing seal valve 55, check (non-return) valve 46 and stop valve 43.

Example 1

The colloidal aluminium hydroxide that contains the new precipitation of 146.2 grams in 78.3 premium on currency to the fine calcium carbonate that wherein adds the new precipitation of 281.9 grams, is made liquid reinforced suspension.The grain diameter of hydroxide is little more many than carbonate, but can just stop up the 0.2 micron hollow fibre of polypropylene through hydrophilic treated very soon.Therefore, in order to separate concentrate fast, at first to remove hydroxide.

Suspension material liquid feeds the cross flow one inspissator of the above-mentioned type, and wherein the hollow fibre area is one square metre, passes the filter membrane backwash with clear liquid and air.Housing porch suspension material liquid pressure is 200 kPas, and outlet pressure is transferred to 100 kPas.The clear liquid flow does not give adjusting.When the clear liquid productive rate drop to be lower than regeneration value last time 80% the time, under 500 kPas of pressure, pass filter membrane and carry out backwash with clear liquid and air.

Beginning moves twice under the pattern that inspissator at one end seals, and productivity ratio descends fast.Required time when having write down clear liquid productive rate in twice experiment and dropping to initial value 80%.The solids content of suspension material liquid has increased, because clear liquid and the solid discharge that is transferred go out system, and the average solids content of calculating the suspension material liquid that is changing according to analysis and clear liquid volume to trasfer of solids.

Analyzed aluminium and the calcium in the trasfer of solids, just can evaluate the selectivity of removing aluminium.For quick concentrating and separating, it is critical selectively removing quick tamper earlier.

After aluminium is removed, stop up and to cause that the rate of discharge 20% required time (in second) that descended just elongated, this just shows that chocking-up degree has reduced.Said " 20% silt index " that is defined as practical application during this period of time, but need to proofread and correct, to provide a homogeneous solid content at the suspension material liquid of this section period.Along with the solid concentration in the rapid discharge suspension material liquid of clear liquid rises continuously, this result has shortened duration of congestion again and has hindered the effect that selectivity is removed aluminium during the purification of inspissator system, and selectivity can prolong duration of congestion except that aluminium.

Done approximate correction, way is the solids content that 20% silt index be multiply by average suspension material liquid under this time.Like this, corrected silt index is approximately equal to 20% silt index under the 1 grams per liter solids content.When suspension material liquid is kept a constant density, relatively be preferably in accurately under constant density (cleaning) pattern and carry out.

After the test of one end closed mode was finished, system transferred the cross-flow operation under clear liquid and air discharge pattern to.Again the results averaged of two kinds of backwashes and repeated experiments.The indicated selectivity of experimental result shifts quick obstruction solid and lists in the table I to reducing the influence of stopping up frequency and increasing total seepage discharge.

Show with the cross flow one filtration test of air discharge pattern then with liquid earlier, it is three times of an end closed mode that selectivity is removed filtering rate that aluminium hydroxide obtains, illustrates that the cross flow one pattern is not more stirred suspension material liquid " candle light " pattern or an end closed mode is all superior.The clearance that improves aluminium hydroxide just can prolong the correction time between twice backwash, is equivalent to 285% of closed mode at one end correction time this correction time.

20.3 liters of concentrates to remnants are analyzed.Inspissator good flushing and air blowing have been carried out.In the remaining concentrate aluminium dilution 13% gone because there is part aluminium optionally to be rejected in the part of transfer.The material that adheres in the inspissator is easy to remove with hydrochloric acid.

Example 2:

City tap-water is fed in the cross flow one inspissator, and it comprises the polypropylene fibre of a branch of 2500 hydrophobics, and every is 500 millimeters long and 200 micron pore size, 200 microns wall thickness.Fiber is with the pre-wetting mistake of isopropyl alcohol.The suspension material liquid inlet pressure is 60 kPas, and outlet pressure is lower than 2 kPas (counter-pressure of clear liquid can not be surveyed).Like this, on average passing filter membrane pressure is 29 kPas.

Liquid was the discharge of air then before this, carried out for 6 seconds in per 2 minutes under 500 kPas of pressure.After the circulation, the liquid rate of discharge dropped to 100 liters/square metre/hours from 480 liters/square metre/hours several times, this be since air be blocked in fiber than in the macropore, and stopped too low 29 kPas pass filter membrane pressure.Further discharge, cause fiber to be stopped up by air in fact entirely with air.

In this experiment that repeats respectively, air stops up available following method and slowly removes:

(a) improve average penetration filter membrane pressure,

(b) flow of raising suspension material liquid,

(c) under the operating condition of inspissator, with air suspension material liquid is done the unsaturation dissolving,

(d) (a) and (b) in conjunction with adopting, and

(e) with (a), (b) with (c) combination employing.

Reduce the fluid flow that surface tension also can be recovered to discharge.

Temperature is to some complexity that influences of suspension material liquid, and low temperature helps the dissolving of gas, and high temperature helps the diffusion of gas.These influences will certainly be cancelled out each other, and up near boiling temperature, at this moment the solubility of air is minimum, make to clean very slowly, have only above bubble point pressure just can obtain satisfied result.

Example 3:

Repeat example 2, the filter membrane pressure that penetrates of employing is that 50 kPas and cross flow are 3600 liters/hour, 25 ℃ of temperature.Hydrophobic fiber is very fast to be stopped up by air, and infiltration rate drops to 75 liters/square metre/hours.

Then the suspension material liquid inlet pressure is risen to 6.5 kPas from 60 kPas, obtaining flow is 113 liters/square metre/hours, and this flow was kept stable at 10 minutes in the duration of test.

The table II is inlet suspension material liquid pressure resulting result when 85 kPas of substeps are elevated to 322 kPas:

The table II

The pressure that increases suspension material liquid is to the influence of bubble point pressure to the clear liquid discharging amount

Suspension material liquid pressure clear liquid discharging amount elapsed time

(kPa) rise/square metre/hour (minute)

Begin to end

85 139 113 26

105 138 124 14

125 157 128 26

148 157 141 5

168 171 156 13

190 189 163 15

210 211 200 4

233 200 189 11

255（＊） 211 248 11

295 360 360 9

322 360 360 7

(*) bubble point pressure; This first evidence of removing is stopped up in attention after surpassing bubble point pressure.

Then suspension material liquid is improved, its method is to add the 0.02%(weight per volume) neopelex in solution, stop up to help removing air.That obtains under different inlet pressures the results are shown in Table III:

The table III

Adopting surfactant to remove air stops up

Suspension material liquid pressure clear liquid discharging amount elapsed time

(kPa) rise/square metre/hour (minute)

Begin to end

322 480 480 2

100 280 370 20

322 1100 stable 2

85 470 get back to wetting entirely

It may be noted that from above result hydrophobic fiber initial obstruction when liquid/gas is discharged is very fast.The pressure that utilizes suspension material liquid to pass filter membrane can make flow increase to some extent, but few (also the reducing in some cases) that increase estimates that the increase of flow is greater and be added on some holes of opening by hydraulics pressure.Infiltration capacity slowly downward trend shows the compression of fiber holes or the influence of obstruction, surpass the influence that any air slowly diffuses out in the hole.

Add in the sharp increase of the bubble point pressure clear liquid output utmost point, just slowly and stably rise then.Can see that air discharges in clear liquid.

In suspension material liquid, add suddenly wetting agent, the output of clear liquid is had surprising influence.As giving material, it is better than being diluted in same quantity in the solution to use dense wetting agent.

The result shows, if adopt liquid and air to discharge, the way of the most handy insoluble hydrophilic material coated becomes permanent hydrophilic with hydrophobic fiber.

Certainly this is applicable to less hole, and this class Kongzui remains full of liquid well, if these holes are in their intrinsic hydrophobic state, just may be stopped up by gas.Be under the gas blocked state, they come again wetting compared with bigger Kong Gengnan by improving feed pressure, some bigger holes when each gas backwash all by purge, because the gas backwash pressure surpasses their bubble point pressure, if but suspension material liquid pressure surpasses bubble point pressure, gas blocks again can very fast removing.The hole of bubble point pressure between these two pressure, the most difficult wetting state that maintains.

When hydrophobic fiber is used for the cross flow one pattern, can in suspension material liquid, use the suitable surfactant of a fritter.Using potassium oleate to do under the situation of surfactant, it is bound to be consumed by the dilution calcium salt in the suspension material liquid jar, forms insoluble oleic acid calcium, and it is repelled by fiber.

If do not allow to add surfactant, should reduce intrastitial temperature and should under this temperature, apply the high-penetration filter membrane pressure that can allow suspension material liquid.Concentration systems is operated under the sort of pressure, up to clear liquid output no longer owing to remove air stop up increase till.

When the gas obstruction takes place once more, need repeat above-mentioned two kinds of processing.When containing biological substances such as resembling sugar, juice, milk, starch wastewater and beer brewery water in the suspension material liquid, fiber very fast owing to adsorbed hydrophilic substance become hydrophilic, and the above-described remedial measure several hrs that only need be used to bring into use.Hydrophilic substance is often removed by the Chemical cleaning step, so above-mentioned processing need repeat.

Example 4:

50 premium on currency are separated the wheaten starch sample with 50 tm screen coarse filtration, add aliphatic acid again to obtain muddy suspension.By device shown in Figure 4, this device adopts polypropylene hollow fibre inspissator with this suspension, and it is connected on the transferring path of transfer valve 30, and valve 55,46 and 43 are not installed.In advance that fiber is wetting with surfactant solution, for quick humidification, give this solution with pump pressure, then clean it with water.Suspension material liquid pressure is 200 kPas, and its counter-pressure is 160 kPas, and clear liquid output is 58 liters/hour, reduces to 31 liters/hour after 24 minutes.

Use a small amount of clear liquid backwash fiber in the clear liquid pipeline then, its consumption surpasses the total fiber pore volume, is that the way of 500 kPas air is carried out the impact type flushing with adding upward pressure suddenly.Then feed the air in 10 seconds.Under 400 kPas, fiber holes is only big by slight support, is fully supportted big under 500 kPas.

Clear liquid output returns to 58 liters/hour of beginning at once.Through after 15 minute a period of time, clear liquid output has dropped to 31 liters/hour again again.Repeat flush cycle again, get back to 58 liters/hour when beginning again again.Whole circulation has repeated again one time, draws the same curve of Fig. 3.

This reluctant suspension contains dense solid, the quick separation of this suspension is promptly produced the concentrate and the filbert clear liquid of clarification of thickness.The inventive method your presentation is smashing.Particularly need gas to come the swelling fiber surface and remove lip-deep concentrate to lump, this point is confirmed by the inspissator experiment of transparent shell.

Example 5:

Inspissator with hydrophilic crosslinked polyamide lining, is made with this composite in hole on the polypropylene hollow fibre of hydrophobic, be used for the sticking protein of thickened waste egg.Inspissator has transparent shell.When the suspension material liquid average pressure was 100 kPas, initial clear liquid flow was 20 liters/hour, but reduced to 12 liters/hour after 20 minutes.

The sticking protein coated that can see thickness and it seems it is that surperficial frozen glue layer has limited flow on fiber.Carried out verifying the test of this supposition, only under 500 kPas of pressure, oppositely passed through with air.Can see the sign of removing surperficial concentrate accumulation, but clear liquid output only is raised to 15 liters/hour.

It's only 5 seconds is past the clear liquid reverse flow of pressurizeing, and pressure is for making big 500 kPas of hole support, so that the pore volume in the liquid displacement hole so just returns to flow initial 20 liters/hour.We find earlier to wash for 5 seconds with clear liquid, wash for 3 seconds with air again, and two kinds are all carried out making under the 500 kPas big pressure of hole support, even use three times high dense sticking proteins, also can return to identical flow with gluing protein.

Like this, just as can be seen, support the method that material in the hole is removed in the mode back flush of macropore, all be effectively to all holes, but can not fully remove surperficial concentrate with clear liquid.The effect of gas is the most favourable to removing the surperficial concentrate that has formed the frozen glue limiting layer.Synergy is absolutely necessary.

Example 6:

Carried out the comparative test of filter, raw materials used is iron hydroxide, two used inspissators, and one resembles shown in Figure 4ly, and another just is provided with valve 43,46 and 55.Experiment shows, for previous inspissator, in the cleaning process to fibre bundle (first seal casinghousing comes pressurized cavity, puts pressure then), only just finished backwash operation with half of improvement inspissator required circulation timei.

Example 7:

With vanilla extract is reform example 6 and obtain similar results of raw material.

Example 8:

Suspension material liquid is made up of the diatomite of the bentonite of 2.5 grams per liters and 2.5 grams per liters, and temperature is 43 degrees centigrade.Feed liquid is with the systems compliant of hollow fibre cross flow one concentration and Fig. 4 of narrating previously, and clear liquid carries out pulse backwashing in tins 47 with being detained, and consumption only equals the volume in hole.Per uniform gas discharging of carrying out for 4 seconds in 10 minutes.

Inspissator feeds running water with 800 liters/hour at first.Bentonite/diatomite suspends

Claims (11)

1, a kind of method by micro-solid in the micro-filter concentrated suspension liquid in the method, is added to the outer surface of many elasticity being contained in housing or the casing, micropore, hollow fibre with suspension, so:

(a) a part of suspension passes fibre wall, and discharges from fiber lumens as clear liquid,

(b) at least a portion solid is trapped within on the fiber or in the fiber, or in housing, the solid that is not trapped is then discharged by housing with residual liquid,

In the method, described fiber is carried out periodic gas backwash step, described method is characterised in that, is to make them carry out following operation by fiber core by feeding fluid under pressure and gas-pressurized to reach with holding back solid from the housing discharge:

(a) make fluid under pressure pass through all basically holes, thereby all basically holes are all supportted greatly, to wash out any solid of holding back, then

(b) make gas-pressurized pass through above-mentioned bigger hole, its time need be enough to the support of those holes big, removing any solid of holding back in these holes, and the inside of the outer wall of purge fiber and housing, all solids is discharged by housing, transfer to the collected outside point.

2, method according to claim 1 is characterized in that, uses the step of gas-pressurized to comprise:

(a) its pressure of gas that originally uses is lower than the bubble point pressure of fibre wall, so that any liquid in the displacement fiber lumen,

(b) outer surface of usefulness liquid seal casinghousing and fiber,

(c) pressure with gas is elevated to more than the fibre wall bubble point pressure, and

(d) remove fluid-tight, make captive gas can pass fibre wall basically equably and overflow.

3, method according to claim 2 is characterized in that, the liquid that seal casinghousing is used is feeding liquid.

According to any one described method among the claim 1-3, it is characterized in that 4, each step is that the repetitive cycling utilizing solid to hold back to discharge with solid is as the continued operation process flow operation in the described method.

5, method according to claim 4 is characterized in that, what described solid discharge step was followed later is the interpolation step of wetting agent.

6, method according to claim 4, it is characterized in that, after solid is discharged step, recover operation that suspension material liquid flows through fiber and need postpone till to be enough to make supportted and just carry out after big hole returns to time in their original apertures, so that cross the hole that the particle of coarsegrain can not enter or pass through to support big in the suspension material liquid.

7, method according to claim 4, it is characterized in that, the recovery feed operation of after the solid discharging operation, then carrying out, be to be enough to make bubble remaining in the fiber holes to dwindle at pressure, impelling bubble in the hole, to discharge, and keep gas and in feed liquid and/or clear liquid, have under the pressure of enough solubility and carry out.

8, method according to claim 6, it is characterized in that, flowing of wherein said delayed recovery suspension material liquid, reach by following step: add the gas that pressure is higher than suspension material liquid pressure, and the pressure that makes this gas drops to and is lower than feed pressure, the hole that its decompression rate needs to make fiber returns to their original aperture before feed liquid flows recovery.

9, method according to claim 1 is characterized in that, the wherein said suspension material liquid stream that leaves the processing of housing needs to be controlled with valving, so that a counter-pressure to be provided to feeding liquid.

10, a kind of inspissator (10) with micro-solid in the concentrated suspension material liquid of the described method of claim 1-9, it comprises:

(I) filter housings (11),

(II) is a kind of to be contained in the polymer fiber (12) of many elasticity in (11), hollow, micropore,

(III) suspension inlet (15) and relative assembly thereof, they are used for the suspension feeding liquid of pressurization is delivered to the outer surface of fiber (12),

The outlet of (IV) cavity (16) and relative assembly thereof, they are used for clarified solution is discharged to gatherer from fiber core,

(V) cavity inlet (18) and relative assembly thereof, they are used for earlier with the liquid that pressurizes, then the gas of pressurization is sent into fiber core to realize penetrating the effect that filter membrane cleans fiber (12), the pressure of fluid under pressure will be enough to support all basically holes of big fiber (12), the pressure of gas-pressurized also wants sufficient to guarantee gas can pass through the bigger hole of fiber (12), its time need be enough to remove any solid of wherein holding back, and the outer wall of purge fiber (12) and housing (11) inside, so that all solids is got rid of the bleeding point of transferring to the outside from housing (11).

11, according to the described a kind of inspissator of claim 10, this inspissator also comprises suspension inlet (15), suspension outlet (17) and relevant device thereof, they be liquid in fiber core by gas displacement after, the suspension material liquid that is used for not compressing relatively is sealed in the housing (11), thereby make gas can under the pressure that is higher than the fibre wall bubble point pressure, be trapped in device in the chamber, and can discharge gas suddenly, make its device by fibre wall equably basically.

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