EP2621863A1 - Dispositif pour purifier l'eau - Google Patents

Dispositif pour purifier l'eau

Info

Publication number
EP2621863A1
EP2621863A1 EP11761350.5A EP11761350A EP2621863A1 EP 2621863 A1 EP2621863 A1 EP 2621863A1 EP 11761350 A EP11761350 A EP 11761350A EP 2621863 A1 EP2621863 A1 EP 2621863A1
Authority
EP
European Patent Office
Prior art keywords
cavitation
light
water
polluted water
main light
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP11761350.5A
Other languages
German (de)
English (en)
Inventor
Rahul Kashinathrao Dahule
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from PCT/EP2010/064239 external-priority patent/WO2012041360A1/fr
Application filed by Individual filed Critical Individual
Priority to EP11761350.5A priority Critical patent/EP2621863A1/fr
Publication of EP2621863A1 publication Critical patent/EP2621863A1/fr
Withdrawn legal-status Critical Current

Links

Definitions

  • the invention relates to a device for purifying water comprising :
  • reactor housing having an inlet opening for supplying polluted water and an outlet opening for draining the purified water from the reactor housing;
  • hydrodynamic cavitation means arranged in the reactor housing for causing hydrodynamic cavitation in the polluted water
  • main light means for irradiating the polluted water with ultraviolet light.
  • US 4990260 describes a device for purifying water comprising two separate steps. In the first step, the polluted water is transported through a venturi, arranged in a reactor chamber, such that cavitation is caused. In the second step the oxidizable contaminants are oxidized by UV light in a separate reactor chamber.
  • This invention exploits hydrodynamic cavitation, which is the result of a substantial pressure reduction in the liquid at a constant temperature. If the pressure is reduced and maintained long enough below a certain critical pressure, determined by the physical properties and conditions of the liquid, cavitation will result.
  • the Shockwave caused by the implosion of the bubbles will disrupt or weaken microbes in the polluted water.
  • the implosion of a bubble generates a micro-jet, which depends on the intensity of cavitation and can break the cell wall of nearby microbes or even completely destroy the cells of microbes.
  • Cell disruption takes place by a combination of several actions of cavitation such as high velocity liquid jets and shock waves.
  • cavitation Another aspect of cavitation is the decomposition of water.
  • liquid vapour tends to condense at the bubble wall. But during extremely rapid transient bubble collapse, the vapour at the centre of the bubble has insufficient time to escape and this excess vapour is trapped in the bubble at the time of minimum radius reached during the collapse when the temperatures and pressures inside the bubble is at the extreme. At these conditions the vapour inside the bubble can decompose to yield OH radicals which get mixed with the bulk liquid when the bubble bursts during the transient collapse and induce various chemical reactions. This chemical effect of cavitation is known as the sonochemical effect .
  • the short lived radicals are capable of oxidation and reduction in the immediate vicinity of the bubble. With cavitation, Hydroxyl (OH.) and Hydrogen (H.) radicals are formed. These radicals initiate chemical reactions and lead to degradation of organic pollutants. Hydrogen peroxide, a strong oxidizing agent, can be formed by the reaction between two hydroxyl radicals.
  • UV light is used to further inactivate microorganisms, which are not or only slightly affected by the cavitation process.
  • UV light is the electromagnetic radiation in the range of 100-400 nanometers (nm) . From this range, the range of 200 - 280 nm is particularly important as light within this range is absorbed by DNA (or RNA in some viruses), causing the destruction of the DNA and accordingly of the microbe. UV light causes the damage of the DNA and can also trigger a photochemical reaction affecting other bio-molecules like proteins and repair enzymes. Biochemical reactions induced by UV such as Protein absorption in the wavelengths ranging from 240 to 280 nanometers (nm) effectively inactivates microorganisms by irreparably damaging their nucleic acid. The most potent wavelength for damaging DNA is approximately 265 nm. Certain wavelengths of UV light also produce free radicals providing oxidation.
  • UV rays can also be used to trigger advanced oxidation, producing hydroxyl radicals in various modes such as vacuum UV photolysis ( wavelengths lesser than 190 nm) , titanium dioxide catalytic UV, hydrogen peroxide assisted UV ( wavelengths lesser than 300 nm )etc.
  • Mold/fungi, bacteria and viruses are the three basic types of biological contaminants, and are all susceptible to UV energy. The dose of UV needed to affect each group varies. Generally, viruses are the easiest to sterilize, followed by bacteria. Mold and fungi are the hardest to eliminate and require very long exposure times.
  • the invention is related to hydrodynamic cavitation and not to acoustic cavitation.
  • AC Acoustic Cavitation
  • the ultrasound waves pass through the medium in a series of alternate compression and expansion cycles.
  • the acoustic amplitude is large enough to stretch the molecules during its negative pressure (rarefaction) cycle to a distance that is greater than the critical molecular distance to hold the liquid intact, microbubbles are created that then collapse in the subsequent compression cycle, giving rise to extremes of temperature and pressure.
  • temperatures greater than 5,000°C and pressures greater than 1000 atm can be produced locally during the collapse of these vapor bubbles.
  • Hydrodynamic Cavitation is a pressure variation in a flow of liquid due to pressure variation in velocity of flow which is a result of change in geometry.
  • the pressure variation in HC is substantially linear.
  • HC is generated by pressure reduction, which is present throughout the main/bulk part of the liquid, while AC only affects a small part of the liquid.
  • the actual volume of the bulk liquid exposed to cavitation is higher for HC than that in AC.
  • bubble/cavity collapsing behavior in the case of HC is accompanied by a large number of pressure pulses of relatively smaller magnitude, compared with just one or two pulses under AC.
  • the radial motion of a bubble due to time variation of bulk pressure in the liquid medium and overall bubble dynamics are different in AC and HC .
  • a problem with the known devices is photo-reactivation and dark repair by UV irradiated microbes. Under certain conditions, some organisms are capable of repairing damaged DNA and reverting back to an active state in which reproduction is again possible. Typically, photo-reactivation occurs as a consequence of the catalyzing effects of sunlight at visible wavelengths outside of the effective disinfecting range. The extent of reactivation varies among organisms. As this publication is not focused on killing the organisms, some of these organisms are capable of repairing themselves despite the combined effect of cavitation and UV light.
  • US 6555011 uses acoustic cavitation along with polarity of energies such as a monochromatic pulsed laser, a microwaves, a Tio2 ( p h o t o c a t a 1 y s t ) coated surface to concentrate diversified electromagnetic and acoustic energies in a compounded concentrator geometry.
  • the acoustic energy is used to cause acoustic cavitation, which could be time synchronized with UV-light.
  • the main light means provide a pulsed ultraviolet light, which is synchronized with the hydrodynamic cavitation mechanism in the polluted water.
  • cavitation improves the penetration of UV light through the microbial cell membrane. Also, cavitation can facilitate the disagglomeration of micro-organism clusters in solution, such that the UV light can more easily reach the individual micro ⁇ organisms .
  • cavitation occurs at a length scale (ranging from few micrometers to few nanometers ) which is typically also the size of the microbial cell.
  • the cavitation increases the pressure and provides disagglomeration, which increases the effectiveness of the ultraviolet light on the microbes .
  • hydrodynamic cavitation affects larger volumes and is uniform throughout the water processing chamber due to efficient mixing and thus there is no problem of directional sensitivity. Because of large number of pressure pulses of relatively smaller magnitude in HC reactor compared to those in the AC reactor, number of active UV pulse synchronization with specific yet variable hydrodynamic cavitation event (s) are maximized at an optimal energy input which further catalyses the events of killing action on the microbes .
  • Synchronizing Pulsed UV with selective hydrodynamic cavitation event (s) thus triggers an optimal energy transformation for the microbial disinfection at complementary mechanisms of UV and hydrodynamic cavitation.
  • This combined synchronization optimally delivers energy for the maximized killing efficiency for the microbial disinfection on the length scale of transformation in contrast to conventional methods of disinfection, where most of the energy is wasted in raising the energy level of whole bulk of liquid which otherwise is not required .
  • this invention can also be used to address mass transfer intensification to accelerate chemical or mixing processes in liquid-liquid or gas-liquid mediums.
  • the bubble collapse event (mode of transient cavitation), within the cavitation, falls at an interval of simmer time of pulsed UV. This way upon release of energy from the bubble collapse, pulsed UV can be easily penetrated into the weakened / disrupted microbial structure.
  • the main light means can comprise additional light means which also provide pulsed UV light and which overlaps with the other pulsed UV light.
  • the pulsed UV cycle may be matched with the oscillation frequency of the cavitation bubbles so that there is successive action of a peak power pulse of the UV followed by the imposed, yet increased, stress resulting from the oscillation of the cavity.
  • variable energy dissipation rate in the water resulting from the variable turbulent shear stresses developed with bubble oscillations from the stable cavitation can additionally be synchronized with the pulsed UV.
  • pulsed UV synchronization can be selectively performed based on the respective yet different cavitation event (s) along the differential cavity trajectories of stable and transient cavitation modes.
  • Design parameters of pulse width and pulse frequency can be altered to change the simmer time and can be made dependent on the size of the cavitation bubble and bubble collapsing duration, which typically varies from 1CT 8 to 1CT 3 seconds.
  • the main light means are positioned downstream from the cavitation means near the implosion area.
  • the position of the main light means is variable.
  • the device can be tuned to the composition of the polluted water entering the device.
  • the composition of the polluted water could influence the cavitation characteristics as a result of which the optimal position of the main light means may have to be varied.
  • Main light means could be smart combination of pulsed polychromatic lamps such as Xenon-based flash lamps, surface discharge lamps, and/or monochromatic UV LEDs, dielectric barrier discharge lamps.
  • Another preferred embodiment comprises secondary light means for continuously irradiating the polluted water with ultraviolet light.
  • the light means are arranged axially or concentrically relative to the water flow. This ensures that the light means irradiate the cavitation zone evenly.
  • the light means could comprise an elongate lamp, a ring shaped light and/or a spiral shaped light.
  • UV LEDs and dielectric barrier discharge (DBD) UV lamps of different monochromatic wavelengths can be used as secondary light means in the vicinity of the bubble collapse to accelerate timely UV penetration towards the microbes.
  • the secondary light means contribute to the effect of the main light means.
  • Reflector materials such as polished sheet of aluminum, Alzak
  • Reflector materials along the inside walls of the water processing housing may be considered for the selective surface to further optimize the variable synchronization of main and/or secondary light means with variable hydrodynamic cavitation event (s) .
  • Yet another embodiment of the device according to the invention comprises a sensor for registering the cavitation frequency of oscillating bubbles which may or may not burst, wherein the sensor is coupled to the main light means.
  • the frequency of the main light means can be controlled, such that the light is synchronized with the cavitation. It must be understood that a number of such frequencies can be controlled since each of these frequencies will indirectly represent variable synchronization event (s) of main/secondary light means with variable hydrodynamic cavitation event (s) .
  • the cavitation means may additionally comprise ultrasound means producing an acoustic wave for causing secondary cavitation , and are coupled to the main light means to synchronize the pulsed light with the cavitation effect.
  • the ultrasound means can be supplemented with other cavitation means.
  • the ultrasound means cause acoustic cavitation, which can contribute to the main hydrodynamic cavitation with intense, rapid and localized collapse of the bubbles.
  • secondary acoustic cavitation may be considered for inactive and/or selective cavitation zone inside the water chamber.
  • the main hydrodynamic cavitation is combined with secondary acoustic cavitation.
  • the cavitation reactor-area following a point where air is sucked in is a potential region of local formation of hydrogen peroxide .
  • Another preferred embodiment of the device according to the invention comprises an air-inlet arranged downstream of the hydrodynamic cavitation means, such that the reactor area where air is sucked into the polluted water, which is a potential region of hydrogen peroxide formation.
  • this zone is irradiated with continuous or pulsed UV rays of monochromatic wavelength preferably in the range of 210-225 nm. This action maximizes the killing mechanism on the microbes with combined UV and hydrogen peroxide assisted advanced oxidation in the selective area of the reactor.
  • a filter or a hydrocyclone connected to the outlet opening of the reactor housing is provided.
  • This filter may be used to remove the debris of microbes.
  • the cavitation means of a device according to the invention can comprise at least one venturi and/or at least one orifice plate having a plurality of holes.
  • the light means are preferably arranged adjacent the orifice plate on the cavitation side.
  • the light means are to be arranged outside of the plurality of holes, in such a way that the light means do not block the holes.
  • the light means could be arranged at the outer boundary of the orifice plate, or in between the plurality of holes. Alternatively the light means could also be individually arranged for each of the individual hole on the orifice plate. UV light reflectors and/or peripherals of the light means such as electrodes, vibration-proof assembly, supporting system, wiper system, earthing may be arranged on the orifice plate without blocking the holes.
  • the hydrodynamic cavitation means are concentrically arranged with the water flow. This ensures that the generated hydrodynamic cavitation spreads evenly over the water to be purified.
  • a gas supply is arranged upstream of the hydrodynamic cavitation means to selectively synchronize specific cavitation event (s) associated with gas bubbles and/or bubbles with substantial gas content with pulsed and/or continuous UV.
  • Pulsed UV synchronization in such gas-fed venturi configuration is done differently on gaseous bubbles. This synchronization is thought to be more energy efficient to provide ease of control and scale-up options.
  • the gas supply was positioned to as to introduces gas bubbles into a selected number of holes of the orifice plate and triggers cavitation event (s) along the paths of gaseous cavities which get selectively synchronized with variable operating parameters of pulsed UV.
  • Two hydrodynamic cavitation means with UV light means can also be combined in parallel, wherein the outlet openings of both cavitation means are combined to collide with significant kinetic energy and shear in the center. This could improve the synergetic effect as the water flow in which the cavitation and UV effects occur is combined towards the single outlet opening.
  • the mixing zone from the collision area may additionally be irradiated with extra UV light means to bring out magnified synergy from the dual action of hydrodynamic cavitation and UV.
  • the said extra UV light means for this purpose can preferably be arranged in/around the collision cluster and in the perpendicular direction to the flow for their ease of removal and exchange .
  • Figure 1 shows a schematic cross sectional view of a first embodiment of a device according to the invention.
  • Figure 2 shows a schematic cross sectional view of a second embodiment of a device according to the invention.
  • Figure 3 shows a schematic cross sectional view of a third embodiment of a device according to the invention.
  • Figure 4 shows a schematic cross sectional view of a fourth embodiment of a device according to the invention.
  • Figure 5 shows a side view of an orifice plate of figure
  • Figure 6 shows a schematic cross sectional view of a fifth embodiment of a device according to the invention.
  • Figure 7 shows a side view of a variant of an orifice plate for the invention.
  • Figure 1 shows a first embodiment 1 of a device according to the invention.
  • the device 1 has a reactor housing 2 with an inlet opening 3 and an outlet opening 4. Both the inlet opening 3 and the outlet opening 4 have flanges 5, 6 with which the reactor housing 2 can be mounted into a pipeline.
  • a venturi 7 is arranged downstream of the inlet opening 3 in the reactor housing 2. When polluted water is fed to the inlet opening 3, the water is subjected to cavitation by the venturi 7, such that cavitation bubbles 8 are created.
  • main light means 9 Downstream of the venturi 7 main light means 9 are arranged. These main light means 9 can provide polychromatic pulsed ultraviolet light for irradiating the polluted water at the cavitation zone 10.
  • a sensor 11 is provided for sensing the frequency of the cavitation, such that a controller 12 can control the main light means 9 based on the frequency of the cavitation and thus synchronize the pulsed ultraviolet light with the cavitation.
  • secondary light means 13 which provide a monochromatic ultraviolet light to assist in the purifying of the water. These secondary light means 13 are used in this embodiment to irradiate the selective reactor area where there is a potential formation of hydrogen peroxide.
  • the monochromatic light from the secondary light means could originate from a DBD lamp and could be pulsed.
  • Figure 2 shows a second embodiment 20 of a device according to the invention.
  • a reactor housing 21 Within a reactor housing 21 an orifice plate 22 and a venturi 23 are arranged in series.
  • the orifice plate 22 is provided with a plurality of holes, such that cavitation zone 24 is generated downstream of the plate 22.
  • This cavitation zone 24 is irradiated with polychromatic pulsed ultraviolet light 25 with the same or a different polychromatic spectrum to destroy the microbes within the water.
  • the polluted water is subjected to cavitation again, resulting in a second caviation zone 26.
  • This second cavitation zone 26 is again irradiated by polychromatic pulsed ultraviolet light 27 to further destroy the microbes within the water.
  • FIG. 3 shows a third embodiment 30 according to the invention.
  • This third embodiment 30 has a reactor housing 31 with an inlet opening 32 and an outlet opening 33.
  • a venturi 34 is arranged in the housing 31 causing a cavitation zone 35 in the polluted water, which is fed to the inlet opening 32.
  • This cavitation zone 35 is irradiated by polychromatic pulsed ultraviolet light from main light means 36.
  • an air inlet 37 is arranged through which ambient air A is sucked into the polluted water as a result of the low pressure.
  • Secondary light means 38 are provided to have the water continuously irradiated with preferably monochromatic ultraviolet light, to trigger advanced oxidation with UV and locally formed hydrogen peroxide in the selective area within the reactor.
  • Figure 4 shows a cross sectional view of an embodiment 40 according to the invention.
  • the embodiment 40 comprises a reactor housing 41 with two separate inlets 42 and one outlet 43. Inside each inlet part 42 an orifice plate 44 is arranged to provide hydrodynamic cavitation in the water flow entering the inlet 42.
  • Ring shaped UV lights 45, 46 are arranged downstream of each orifice plate 44 (see also figure 5) . These UV lights 45, 46 are concentrically arranged and promote the elimination of bacteria and the like. UV light means 45, 46 may be optimized to choose one of them to operate in pulsed mode whilst the second one to be operated in continuous mode.
  • FIG. 6 shows a cross sectional view of a fifth embodiment 50 of the invention.
  • This embodiment 50 has a reactor housing 51 with an inlet 52 and an outlet 53.
  • venturi 54 Inside the reactor housing a venturi 54 is arranged and downstream of this venturi 54 is arranged an orifice plate 55. This venturi 54 and orifice plate 55 will create two cavitation zones 56, 57, eliminating bacteria and the like.
  • An elongate UV-light 58 is axially arranged in the reactor housing 51 and extends in both the two cavitation zones 56, 57. This embodiment has the advantage, that the elongate UV- light 58 can easily be exchanged when the light 58 fails.
  • Figure 7 shows a side view of an embodiment 60 of an orifice plate 61 with a spirally shaped UV light 62 placed in front of the orifice plate 61.
  • the holes 63 are preferably also arranged in a spiral shape, such that the spiral UV light 62 can easily be placed in between the holes 63.
  • the advantage of this embodiment is that the UV light 62 is arranged near each hole 63 of the orifice plate 61, while the UV light 62 is still one single part and thus can easily be exchanged.

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Abstract

Cette invention concerne un dispositif (1) pour purifier l'eau comprenant : - une enveloppe de réacteur (2) comportant une ouverture d'admission (13) pour introduire l'eau polluée et une ouverture d'évacuation (4) pour évacuer l'eau purifiée contenue dans l'enveloppe de réacteur (2) ; - un moyen de cavitation hydrodynamique (7) qui se trouve dans l'enveloppe de réacteur (2) pour créer une cavitation (10) dans l'eau polluée ; - un moyen de lumière principal (9) pour irradier l'eau polluée d'une lumière ultraviolette, ledit moyen de lumière principal générant une lumière ultraviolette polychrome et/ou monochrome pulsée, qui est sélectivement synchronisée sur le ou les événements de cavitation spécifiques créés dans l'eau polluée à l'aide d'un capteur (11) et d'un contrôleur (12).
EP11761350.5A 2010-09-27 2011-09-22 Dispositif pour purifier l'eau Withdrawn EP2621863A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP11761350.5A EP2621863A1 (fr) 2010-09-27 2011-09-22 Dispositif pour purifier l'eau

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
PCT/EP2010/064239 WO2012041360A1 (fr) 2010-09-27 2010-09-27 Dispositif pour purifier l'eau
PCT/EP2011/050609 WO2012041526A1 (fr) 2010-09-27 2011-01-18 Dispositif pour purifier l'eau
EP11761350.5A EP2621863A1 (fr) 2010-09-27 2011-09-22 Dispositif pour purifier l'eau
PCT/EP2011/066538 WO2012041766A1 (fr) 2010-09-27 2011-09-22 Dispositif pour purifier l'eau

Publications (1)

Publication Number Publication Date
EP2621863A1 true EP2621863A1 (fr) 2013-08-07

Family

ID=45631039

Family Applications (1)

Application Number Title Priority Date Filing Date
EP11761350.5A Withdrawn EP2621863A1 (fr) 2010-09-27 2011-09-22 Dispositif pour purifier l'eau

Country Status (1)

Country Link
EP (1) EP2621863A1 (fr)

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2012041766A1 *

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