A kind of annoying external pressure pillar hollow fiber film assembly that dashes
Technical field
The present invention relates to a kind ofly, relate in particular to a kind of structure design and using method thereof of hollow fiber film assembly, belong to membrane bioreactor and wastewater treatment and reuse technical field at the employed membrane module of membrane bioreactor.
Background technology
(Membrane Bioreactor MBR) is a kind of new and effective wastewater treatment and reuse technology with membrane separation technique and the combination of traditional biological treatment technology to film-bioreactor.In the application of film-bioreactor, need the larger area film usually.The minimum unit that film is installed is called as membrane module.Membrane module has a variety of forms, can be divided into two big classes basically: tubular type and flat.Membrane module form commonly used has flat sheet membrane, tubular membrane, capillary membranes, hollow fiber film assembly or the like, and its performance sees Table 1-1.
Table 1-1 membrane module performance table look-up
Project | Tubular membrane component | Plate basket formula membrane module | Rolled membrane module | The capillary type membrane module | Hollow fiber film assembly |
External diameter | ??6~25mm | - | ??- | ??0.5~2mm | ??40~500um |
Feed liquid flows | Walk in the pipe | - | ??- | Walk in the pipe | In walking to manage or outside the pipe |
Supporting tube | Have | - | ??- | Do not have | Do not have |
Packing density | Low | Lower | Medium | High | Very high |
Membrane area | Very little | Medium | Medium | Medium | Very big |
The face shearing rate | Very high | Medium | Medium | Medium | Very low |
Membrane flux | Greatly | Greatly | Medium | Greatly | Little |
Cost | High | Medium | Medium | Low | Very low |
Pollution condition | Be difficult for polluting | Be difficult for polluting | Be difficult for polluting | Easily stop up | Easily stop up |
The cleaning situation | Easy cleaning | Easy cleaning | Easy cleaning not | Easy cleaning not | Easy cleaning not |
Range of application | Micro-filtration, ultrafiltration, reverse osmosis | Micro-filtration, ultrafiltration, reverse osmosis, gas delivery | Reverse osmosis, nanofiltration, gas delivery, pervaporation | Ultrafiltration, gas delivery, membrane distillation, pervaporation | Micro-filtration, ultrafiltration, reverse osmosis |
From table 1-1 as can be seen: because hollow-fibre membrane packing density and membrane area are very big, low price, and overcome the not withstand voltage shortcoming of capillary type membrane module, in wastewater treatment, be used widely at present.
For a membrane sepn process, select which type of membrane module to depend on two aspects: one is the character of film itself, and another is the singularity of process.In membrane bioreactor and since handle to as if mud, it is inevitably that film pollutes, and relatively more serious, the amount of sewage is all bigger simultaneously, so should select anti-pollution, kit form that membrane flux is big.Carrying out along with the membrane sepn process, macromolecular substance in the solution, dissolved substance are adsorbed to the film surface, and then enter inner fenestra and the depositional phenomenon of particulate matter on the film surface stopped up of fenestra and be called film and pollute, film promptly shows as the increase of membrane resistance and the decline of membrane flux after polluting.In general, in membrane bioreactor, make the two big class materials that mainly contain that film pollutes.One class is macromolecular substance, the dissolved matter (as microbial metabolites SMP) in the solution, and this class material can be adsorbed to film surface and form gel coat, perhaps and then enter the inner fenestra that stops up of fenestra, is called irreversible pollution.Another kind of material is granular material, carrying out along with the membrane sepn process, this class material can form cake layer at the film surface deposition, the film that grows up like this pollutes often to pollute in the total-resistance at film and occupies bigger ratio, but this pollution generally is a reversible, be called reversible pollution, development how to adopt effective physical means to control reversible pollution is that biological the sending out of film answered the key that controlling diaphragm pollutes in the device.
According to the position that is provided with of membrane module, film-bioreactor can be divided into separated type film-bioreactor and integral type (or immerseable, built-in) film-bioreactor two big classes.Traditional external membrane bioreactor generally adopts column-type film components, and takes the water power operator scheme of single-phase cross flow filter, the water-out manners of the film forming driving pressure of malleation shape that provides by recycle pump.It has, and membrane flux is big, film cleans convenient two main advantages.But, for controlling diaphragm effectively pollutes, often needing bigger crossflow velocity, required flow and lift are bigger, energy consumption also big (be built-in membrane bioreactor 4~6 times).Traditional integral type film biological reactor generally adopts curtain type film assembly, utilizes gas to put forward principle, forms an air water two-phase flow and flows district's circulation in the up-flow district with falling, and the film surface is washed away, and controlling diaphragm pollutes.The water-out manners of the film forming driving pressure of suction pump aspiration vacuum shape that adopts.Its major advantage is that energy consumption is relative to low than external placed type, and land used is economized, but its film cleans inconvenience, and it is higher that film cleans cost, and membrane flux is also less relatively.And, be suspension in the whole reactor because gas carries, the fluid section of air water two-phase flow is also bigger, and how reducing its energy consumption still is people's a significant concern point.About 1.0~the 2.4kwh/m of processing energy consumption of present integral type film biological reactor unit's water yield of using
3(turn round and look at equality, 2000, Chinese water supply and drainage Vol.16 (3), 5-8; Tatsuki Ueda and Kenji Hata 1999, waterreseach, 33,2888-2892).
Can design novel membrane module, external membrane bioreactor and built-in membrane bioreactor are organically combined, get separately the chief, mend shortage separately, make it have that energy consumption is low, flux big, film pollutes slower development, film cleans characteristics easily.
Summary of the invention
Purpose of the present invention just provides a kind of annoying external pressure pillar hollow fiber film assembly that dashes, under the situation of keeping lower aeration rate, higher membrane flux is kept in the development of controlling diaphragm pollution effectively, further reduce its operation energy consumption, realize and keep its long-time running.
The objective of the invention is to be achieved through the following technical solutions.
A kind of annoying external pressure pillar hollow fiber film assembly that dashes, mainly comprise membrane module shell cylinder, be arranged on the intravital U shape of shell post hollow-fibre membrane silk, the material liquid outlet at top, be arranged on the liquor inlet and fixed area that is used for fixing the adhesive film silk and permeate water outlet of bottom, it is characterized in that: in the middle of the film silk of hollow fiber film assembly bottom, is provided with special-purpose gas towards parts.
Gas described in the present invention can adopt boring aeration pipe, micropore aeration pipe or micro porous aeration head towards parts.
Feature of the present invention also is the fluidised form of the movement locus and the two-phase flow of reasonable standard gas, water.This mainly is that the length-to-diameter ratio of film silk, the packing density of membrane module realize by the aspect ratio of setting membrane module shell post.The aspect ratio of the shell cylinder of membrane module of the present invention is 5~20: 1; Described membrane module the length-to-diameter ratio of film silk be 50~300: 1; The film silk packing density of described membrane module is 500~1500m
2/ m
3
The present invention also provides a kind of using method of the annoying external pressure pillar hollow fiber film assembly that dashes, i.e. utilization " subcritical flux methodology " rationally, make the subcritical flux operating area work of membrane module under selected operational condition, described subcritical flux operating area adopts flux stepwise incremental method to determine, can carry out as follows:
(1) under the Xuan Ding operational condition, adopt the method for permanent flux to make a time period of film work Δ T be at least 30min, the variation of observation membrane operations pressure in Δ T, constant if membrane operations pressure keeps, regulate the progression of water outlet suction pump, make membrane flux increase a rank amount; Again observe the variation of membrane operations pressure in another Δ T, so continue, till membrane operations pressure occurring and in Δ T, can not stablizing;
(2) note membrane flux at this moment is F
N+1, i.e. F
N+1For under this operational condition, making the membrane flux of the minimum that membrane operations pressure goes up, F
NMembrane flux for the maximum of membrane operations constant pressure under this operational condition; Then critical flux is between F
N+1And F
NBetween, greater than F
N+1Flux regions be called overcritical flux regions under this operational condition, less than F
NFlux regions be called subcritical flux regions under this operational condition, make membrane module in this subcritical flux operating area work.
The present invention compares with existing hollow fiber film assembly, has the following advantages and the high-lighting effect:
(1) flux is big, and its working flux can reach 15~30L/m
2H.The known membrane flux that generally is used for the hollow fiber film assembly of integral type film biological reactor only is 5~10L/m
2H.
(2) gas-water ratio can be reduced to 20~25: 1, thereby cuts down the consumption of energy.The known gas-water ratio that generally is used for the hollow fiber film assembly of integral type film biological reactor is 40~60: 1.
(3) reduce face cross-flow velocity to 0.04~0.1m/s greatly, thereby reduce circular flow and energy consumption.The known face cross-flow velocity that generally is used for separate film biological reactor is 2~4m/s.
(4) antifouling property is good, owing to directly concentrate aeration in membrane module, is 20~25: 1 o'clock at aeration rate like this, and its aeration intensity just can reach 125~200m
3/ m
2H.Therefore can increase the turbulent fluctuation of membrane module fluidic greatly, the control particulate matter improves the antifouling property of membrane module greatly in the deposition on film surface.
Description of drawings
Fig. 1 is the structural representation that is used for the external pressure pillar hollow fiber film assembly of separate film biological reactor provided by the invention.
Fig. 2 is the external pressure pillar hollow fiber film assembly structural representation that is used for integral type film biological reactor provided by the invention.
Fig. 3 represents that external pressure pillar hollow fiber film assembly is used for the process device figure of separate film biological reactor.
Fig. 4 represents that external pressure pillar hollow fiber film assembly is used for the process device figure of integral type film biological reactor.
Embodiment
Below in conjunction with drawings and Examples technical solution of the present invention is further described.
Fig. 1 is the structural representation that is used for the external pressure pillar hollow fiber film assembly of separate film biological reactor provided by the invention.Its main composition comprises that " U " shape hollow-fibre membrane silk 1, membrane module shell cylinder 2, gas export 5 towards liquor inlet 6, the permeate water of parts 3, bottom, the material liquid outlet 7 at top, piezometric tube interface 8 and film silk bonding fixed area 4.
Fig. 2 is the external pressure pillar hollow fiber film assembly structural representation that is used for integral type film biological reactor provided by the invention.Its main composition comprises that " U " shape hollow-fibre membrane silk 1, membrane module shell cylinder 2, gas export 5 towards liquor inlet 6, the permeate water of parts 3, bottom, the material liquid outlet 7 at top and film silk bonding fixed area 4.
Fig. 3 represents that external pressure pillar hollow fiber film assembly is used for the process device figure of separate film biological reactor.This installs by bio-reactor 9, circulating water inlet 13, recycle pump 14, air feeder 10, water outlet suction pump 11, top water inlet pipe 12, pressure warning unit 15 and external pressure pillar hollow fiber film assembly are formed, and the gas that is arranged on membrane module bottom is connected with air feeder 10 towards parts 3.Gas forms the air water two-phase flow with the water outlet of recycle pump and pollutes with controlling diaphragm in membrane module.And the air water two-phase flow flows into from reactor 9 bottoms, makes that on the one hand the feed liquid in the reactor is mixed fully, provides oxygen for the microorganisms in the reactor 9 on the other hand.Mix fully after circulating water inlet 13 is injected in the membrane modules by recycle pump 14 with reactor 9 interior feed liquids by the 12 former water that flow into.The film permeate water is discharged by water outlet suction pump 11 through seeing through water pipe 5.
Fig. 4 represents that external pressure pillar hollow fiber film assembly is used for the process device figure of integral type film biological reactor.This installs by bio-reactor 9, air feeder 10, and water outlet suction pump 11, top water inlet pipe 12 and external pressure pillar hollow fiber film assembly are formed.The gas that is arranged on membrane module bottom is connected with air feeder 10 towards parts 3.Membrane module shell side bottom is provided with opening, when air feeder is given the membrane module aeration, with membrane module shell post jamb is the water conservancy diversion ring flat-plate, in membrane module, form the ascending zone of air water two-phase flow, between membrane module shell post jamb and reactor wall, form the district that descends, thereby form round-robin air water two-phase flow.
The aspect ratio of membrane module shell cylinder is (5-20) among the present invention: 1, the fluidised form of air water unstable flow is a standard to form the Taylor bubble, plenum system can freely be evenly distributed on the membrane module cylinder transverse section bubble for using perforated pipe, micro-filtrate, micro porous aeration head or other vesicular material the centre of gas importing membrane module body skin inner membrance silk.
Unstable fluid motion is meant that in flow system relevant physical quantitys such as flow rate of fluid, pressure, density not only change with the position on each face, and time to time change.Compare with the stable state turbulent flow, unstable flow can both be played the intensive filtration effect under laminar flow and turbulence state, fluid unstable flow flowing mode is that a kind of strengthening effect is good, energy is lower, the simple practical technique of equipment, and efficient to designing, resistant to pollution membrane module has very big pushing effect.The air water two-phase flow is a kind of unstable flow, and appropriate membrane module shell cylinder aspect ratio makes the fluidised form of air water two-phase flow be able to effective development, even under the very little situation of quantity of circulating water, mixes with appropriate tolerance, also is enough to form the intensive unstable flow.
For hollow-fibre membrane, the length of film silk and the ratio of diameter directly influence fluidised form and the film silk axial flux of permeate water in the film silk and distribute.If film silk length-to-diameter ratio is excessive, then the non-outlet terminal membrane flux partly near the film silk will be little more a lot of than the outlet terminal membrane flux partly of film silk, cause the membrane flux skewness.If the film filament diameter is excessive, then can too reduce the specific surface area of film silk.The film silk length-to-diameter ratio that the present invention requires is: 50~300: 1.
The packing density of membrane module can exert an influence to the fluidised form of air water two-phase flow, and packing density is excessive, and the film silk does not just have enough vibration spaces, and turbulent fluctuation will weaken, and is unfavorable for controlling the deposition of particulate matter.The too small meeting of packing density causes the economy of membrane module to descend, and the membrane module packing density that the present invention requires is: 500~1500m
2/ m
3
When the present invention also requires membrane module work, continuous air feed, but membrane module adopts the intermittent suction water outlet.
The present invention rationally uses " subcritical flux methodology " to determine the membrane module using method of film working flux.Critical flux is one and film is polluted the notion that extremely important meaning is arranged, it is meant and has a threshold value in permanent flux filters, when membrane flux was worth greater than this, membrane operations pressure TMP (Transmembrane Pressure) rose rapidly, and film pollutes sharply development; When membrane flux was worth less than this, the film pollution did not take place or develops very slow.Critical flux is relevant with waterpower operational condition, membrane sepn operator scheme, feed liquid character and the character of film own.The subcritical operation of membrane bioreactor just is based on such notion, and under certain operational condition, it is following to obtain the operation of membrane bioreactor long-term stability to make membrane flux maintain critical flux.
Usually, polluted membrane two big class materials are arranged: a class is deliquescent macromolecular substance, as solvability microbial product (Soluble Microbial Products, be called for short SMP) and extracellular polymeric (Extracelluar Polymers, abbreviation ECP is along with the carrying out of membrane sepn, this class material can be adsorbed to the film surface and form gel coat (Gel Layer), it generally is irreversible polluting, but development is comparatively slow, is called irreversible pollution (Irreversible Fouling).Another kind of material is a particulate matter, as the mud flco, this class material forms sludge blanket (Cake Layer) at the film surface deposition, pollution is a reversible, be called reversible pollution (Reversible Fouling), this class is polluted and occupy very big deal (more than 80%) in dead-end filtration, and development rapidly, and it also is the main object of film polluted water kinetic control.In membrane bioreactor, critical flux is also at reversible pollution, and the dominant ideas of subcritical operation are exactly to make film in the process of operation, avoid as far as possible mud granule deposition, avoid reversible pollution.
Embodiment 1
Please refer to Fig. 3 external pressure pillar hollow fiber film assembly and be used for the separate film biological reactor process device figure.The shell cylinder aspect ratio of compression leg formula hollow fiber film assembly is 11: 1 in addition, hollow-fibre membrane silk length-to-diameter ratio 200: 1, film silk packing density 829m
2/ m
3, membrane area 0.5m
2When the mixed solution sludge concentration was 3~10g/L in the reactor, membrane flux can reach 20L/m
2H, recycle pump quantity of circulating water 200L/h, lift 2.0m, unit total efficiency 0.49, then the energy consumption of processed in units water yield water circulating pump is 0.21kwh/m
3Face cross-flow flow velocity can be controlled in 0.04~0.06m/s, and is little more a lot of than the cross-flow velocity 3~4m/s of known separate film biological reactor technology.Aeration rate 250L/h, the 20kPa that boosts, air blast efficient 0.44, then the energy consumption of processed in units water yield gas blower is 0.35kwh/m
3Gas-water ratio only is 25: 1, than the gas-water ratio (40~60: 1) little a lot of of known integral type film biological reactor.Suction pump flow 10L/h, lift 10m, unit total efficiency 0.49, then processed in units water yield suction pump energy consumption 0.06kwh/m
3Then processed in units water yield total energy consumption is 0.62kwh/m
3, than the processed in units water yield energy consumption 3.0~5.5kwh/m of known cross-flow separate film biological reactor
3Little a lot.
Concentrate aeration owing to adopt, make that the aeration intensity in the membrane module can reach 160 ~ 190m
3/ m
2H, the turbulent fluctuation that this has just increased the air water two-phase flow greatly helps controlling particulate matter reaches the reversible pollution of controlling diaphragm in the deposition on film surface purpose, and the rate of increase of the membrane operations pressure of system is 0.15kPa/d.Thereby realize the permanent stable operation of membrane bioreactor.
Embodiment 2
Please refer to Fig. 4 external pressure pillar hollow fiber film assembly and be used for the integral type film biological reactor process device figure.The shell cylinder aspect ratio of compression leg formula hollow fiber film assembly is 6: 1 in addition, hollow-fibre membrane silk length-to-diameter ratio 100: 1, film silk packing density 702m
2/ m
3, membrane area 1.0m
2When the mixed solution sludge concentration was 3~10g/L in the reactor, membrane flux can reach 15L/m
2H, aeration rate 390L/h, the 20kPa that boosts, air blast efficient 0.44, then the energy consumption of processed in units water yield gas blower is 0.49kwh/m
3Gas-water ratio only is 26: 1, than the gas-water ratio (40~60: 1) little a lot of of known integral type film biological reactor.Suction pump flow 15L/h, lift 10m, unit total efficiency 0.49, then processed in units water yield suction pump energy consumption 0.06kwh/m
3Then processed in units water yield total energy consumption is 0.55kwh/m
3, than the processed in units water yield energy consumption 1.0~2.4kwh/m of known integral type film biological reactor
3Little a lot.
But the aeration intensity in the membrane module can reach 130~150m
3/ m
2H, the turbulent fluctuation that this has just increased the air water two-phase flow greatly helps controlling particulate matter reaches the reversible pollution of controlling diaphragm in the deposition on film surface purpose, and the rate of increase of the membrane operations pressure of system is 0.25kPa/d.Thereby realize the permanent stable operation of membrane bioreactor.