Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
  • B03D1/00—Flotation
  • B03D1/02—Froth-flotation processes
  • B03D1/028—Control and monitoring of flotation processes; computer models therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
  • B01F23/20—Mixing gases with liquids
  • B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
  • B01F23/234—Surface aerating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
  • B01F25/20—Jet mixers, i.e. mixers using high-speed fluid streams
  • B01F25/25—Mixing by jets impinging against collision plates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
  • B03D1/00—Flotation
  • B03D1/14—Flotation machines
  • B03D1/1431—Dissolved air flotation machines
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
  • B03D1/00—Flotation
  • B03D1/14—Flotation machines
  • B03D1/24—Pneumatic
  • B03D1/247—Mixing gas and slurry in a device separate from the flotation tank, i.e. reactor-separator type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F2215/00—Auxiliary or complementary information in relation with mixing
  • B01F2215/04—Technical information in relation with mixing
  • B01F2215/0413—Numerical information
  • B01F2215/0418—Geometrical information
  • B01F2215/0427—Numerical distance values, e.g. separation, position
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F2215/00—Auxiliary or complementary information in relation with mixing
  • B01F2215/04—Technical information in relation with mixing
  • B01F2215/0413—Numerical information
  • B01F2215/0418—Geometrical information
  • B01F2215/0431—Numerical size values, e.g. diameter of a hole or conduit, area, volume, length, width, or ratios thereof
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F2215/00—Auxiliary or complementary information in relation with mixing
  • B01F2215/04—Technical information in relation with mixing
  • B01F2215/0413—Numerical information
  • B01F2215/0436—Operational information
  • B01F2215/0481—Numerical speed values

Definitions

• the invention relates to a device for pressurizing a liquid with a gas and to such a device in combination with a device for
• Flotation plants are used to remove solids from aqueous suspensions.
• gas bubbles are introduced into the suspension, which attach to the solids so that they float to the surface of the liquid.
• the particles can then be removed from the surface by means of clearing devices.
• a known method for producing fine gas bubbles is the saturation of a water stream with air at pressures of 3-10 bar. This pressure-saturated water is then added to the water to be cleaned via valves.
• the valve causes a spontaneous drop in pressure from the saturation pressure to the ambient pressure plus the hydrostatic pressure in the flotation apparatus, which suddenly reduces the gas solubility. As a result, the excess gas is eliminated by the formation of fine gas bubbles.
• the object of the invention is to provide a device for pressure saturation and pressure relief, which does not have the disadvantages of the systems of the prior art.
• the solution to the problem according to the invention consists in a device for pressure accumulation containing
• a pressure saturation container - one or more nozzles for injecting liquid into the pressure saturation container at the head of the pressure saturation container, tubes open at the top and closed at the bottom (dissolver tubes), which are arranged below the nozzle (s) in the pressure saturation container, one or more nozzles being assigned to each dissolver tube - liquid outlet below the dissolver tubes at the bottom of the pressure saturation tank.
• the liquid, which is to be saturated with gas, preferably air, is introduced at the head of the pressure saturation tank via one or more nozzles, preferably conventional smooth jet nozzles. These can be screwed into the lid of the pressure saturation tank.
• the pressure loss at the nozzles should be less than 1 bar, preferably less than 0.5 bar, under operating conditions.
• the nozzle diameters preferably have gap widths larger than 4 mm at their narrowest flow cross sections, which means that clogging by fine particles can be excluded.
• the nozzles can be protected by upstream, backwashable sieve filters.
• the flow of the supplied liquid can be divided beforehand into individual feed pipes.
• the liquid flow through the individual nozzles can be regulated separately for each nozzle by upstream or downstream shut-off devices, for example by a battery of shut-off valves.
• the amount of liquid supplied to the pressure saturation container can be adjusted as required.
• the liquid is injected at a speed of more than 3 m / sec, preferably more than 6 m / sec.
• the choice of the speed of the injection depends on the degree of pressure saturation that is to be achieved for the liquid to be saturated. In order to achieve a saturation of more than 90% with water, the speed of the injection should be more than 8 m / sec, for a saturation of more than 95% more than 10 m / sec.
• the liquid in each nozzle first passes through the gas cushion in the space between the nozzles and the dissolver tubes in the form of a free jet and then enters one of the dissolver tubes.
• the distance between each of the dissolver tubes and the associated nozzle is in the range of 100-400 mm, preferably in the range of 150-250 mm.
• the liquid is swirled in the dissolver tubes and emerges from the top of the dissolver tube a short time later. Due to the liquid flowing continuously from each nozzle, the respectively associated dissolver tube is always filled with liquid. Due to the free jet of the liquid through the gas cushion, gas molecules are entrained and introduced in the form of gas bubbles into the interior of the dissolver tube.
• a nozzle is preferably assigned to each dissolver tube, but several, e.g. four nozzles can be assigned to a dissolver tube.
• the residence time of the liquid in the dissolver tubes depends on the one hand on the speed of the injection and on the other hand on the ratio of the diameter of the dissolver tubes to the diameter of the assigned nozzles at the liquid outlet of the nozzles.
• the ratio of the diameter of the dissolver tube to the diameter of the assigned nozzle in the case of an assigned nozzle is preferably in the range from 3 to 8, preferably 3 to 5, particularly preferably 4.
• the ratio of the diameter of the dissolver tube to the diameter of one of the assigned nozzles is in the range from 6 to 16, preferably 3 to 10, particularly preferably 8, because a double diameter of the dissolver tube is assigned a 4-fold throughput through the nozzles. If other nozzle numbers are assigned to a dissolver tube, the ratio must then be adjusted accordingly.
• the residence time of the liquid in the dissolver tubes is less than 10 seconds, preferably less than 5 seconds, particularly preferably less than 2.5 seconds.
• the liquid flows out of the dissolver tubes and collects or accumulates in the lower area of the container, where it can escape through the liquid outlet below the dissolver tubes on the bottom of the container.
• the liquid outlet at the bottom of the gas saturation container is in particular dimensioned such that the outflow speed of the liquid from the gas saturation container is in the range between 50 and 150 m / h, preferably in the range of 70 and 90 m / h.
• the liquid accumulated in the container has the function of a bubble filter. Larger bubbles (d> 100 ⁇ ) cannot get into the liquid outlet as they rise faster than the liquid moves down.
• Liquid in the gas saturation tank is made by regulating the gas supply.
• the level of the liquid in the container can be controlled using a level meter.
• a vertical pipeline outside the gas saturation tank is preferably connected in communication with the tank interior.
• a float in the pipeline indicates the level.
• the float is preferably magnetically detectable and activates a minimum and maximum circuit. In the minimum case, the supply of gas is stopped automatically. In the maximum case, the gas supply is opened.
• the maximum pressure in the tank can be set using a pressure reducing valve in the gas supply line.
• the level meter in combination with the min and max circuits not only regulates the level of the pressure saturation tank with the liquid, but also ensures that the pressure saturation tank is adequately supplied with gas. In this way, as much gas is automatically added to the liquid as is consumed by the dissolving process.
• the achievement of the object according to the invention further comprises a device for pressure saturation and pressure release of liquid for introduction into a flotation cell containing
• a flotation cell a pressure saturation tank, the liquid supply of which is connected via liquid lines to the liquid outlet of the flotation cell, one or more pressure relief valves which are located in the liquid lines between the liquid outlet of the pressure saturation tank and the
• Liquid supply line to the flotation cell are arranged.
• the flotation cell known per se comprises a baffle plate, an inner pot and a device for circular suction evacuation on the outer part of the liquid surface.
• the amount of flotate in the flotation cell is deducted by the Control of liquid inflow (e.g. dirty water inflow) and outflow of the cleaned liquid (e.g. pure water outflow).
• the pressure saturation container can be one of the devices for pressure saturation according to the invention described above.
• the amount of liquid from each pressure relief valve can be connected by a shut-off device upstream or downstream e.g. a ball valve can be regulated.
• a shut-off device upstream or downstream e.g. a ball valve can be regulated.
• the flotation cell can be operated at different gassing rates.
• a central shut-off valve can be arranged between the liquid outlet of the pressure saturation container and the pressure relief valves.
• the pressure relief valves can consist of perforated plates into which one or more nozzles are screwed.
• the perforated plates are fitted into flanges in a similar way to perforated disks.
• the nozzles used in the pressure relief valves can have the flow profile of a simple commercial Laval nozzle.
• the pressure relief valves can consist of plates into which
• Hole or slot nozzles are milled with appropriate flow profiles.
• the nozzle diameters in the pressure relief valves preferably have gap widths greater than 4 mm at their narrowest flow cross sections, which means that clogging by fine particles can be ruled out.
• the nozzle diameters in the pressure relief valves preferably have gap widths greater than 4 mm at their narrowest flow cross sections, which means that clogging by fine particles can be ruled out.
• Nozzles are protected by upstream backwashable sieve filters.
• the pressure relief valves and the feed line to the flotation cell there is preferably a piece of liquid line in which the pressure-released liquid covers a distance in the range from 10 to 100 cm, preferably 10 to 30 cm, before it is mixed into the inflow of the flotation cell.
• This is advantageous is responsible for a complete expulsion of the excess gas from the liquid and for achieving a fine-bubble spectrum of bubbles with bubble diameters between 30 and 70 ⁇ m.
• An advantage of the device for pressure saturation according to the invention is that foam formation is largely prevented. Floating foam bubbles are smashed out of the nozzles by the liquid jets cutting through the gas space.
• the saturation takes place in the device for pressure saturation according to the invention with a particularly high space-time yield, because over 90% pressure saturation can be achieved with short dwell times in the dissolver tubes (less than 10 seconds).
• the devices according to the invention for pressure saturation and pressure relief are constructed from very simple components and can therefore be manufactured at extremely low cost.
• Another advantage of the devices for pressure saturation and pressure release according to the invention is that the connection and disconnection of individual nozzle elements, the liquid throughput and thus the gas input can be flexibly regulated.
• FIG. 1 Structure of a combined pressure saturation pressure relaxation system with flotation cell
• Nozzles in a pressure sump with different outlet openings are provided.
• FIG. 1 shows the structure of a combined pressure saturation pressure relaxation system with the flotation cell 10.
• clear water is led from the outlet 11 of the flotation cell 10 into the pressure saturation tank 1.
• the introduction takes place in a flow-controlled manner at the head of the pressure saturation tank 1 via one or more conventional smooth jet nozzles 8, which are screwed into the tank lid 2.
• the flow of the supplied water is previously divided into individual feed pipes 12, which can be switched on and off individually by a battery of shut-off valves 13.
• the liquid In the pressure accumulator 1, the liquid first passes through the gas cushion 3 in the form of a free jet 14 and then enters a dissolver tube 4, is swirled there and exits again a short time later at the top.
• the water flows out of the dissolver tubes 4 and collects or accumulates in the lower region 5 of the container 1.
• the liquid exits through the liquid outlet 16 at the bottom of the container 1.
• the fill level 17 of the water in the container 1 is regulated by means of a fill level measurement.
• a vertical pipeline 6 is preferably connected outside of the container 1 in communication with the inside of the container.
• a magnetically detectable float 18 in the tube identifies the position of the fill level 17 and activates a minimum and maximum circuit 19 which is connected to a gas passage valve 20. In the minimum case, the supply of gas is stopped automatically. In the maximum case, the gas supply is opened.
• the maximum pressure in the container can be set by a pressure reducing valve 21 in the gas supply line.
• the water flows via a central shut-off valve 22 via one or more pressure relief valves 7, via subsequent liquid line pieces 29 into the feed line 23 of the flotation cell 10.
• Individual pressure relief valves 7 can be switched on or off by the ball valves 24 connected downstream.
• FIG. 2a shows a pressure relief valve 200 consisting of a plate 210, into which perforated or slotted nozzles 220 are milled with corresponding flow profiles.
• the perforated plate 210 is fitted into the flange 230 in a manner similar to a perforated disk.
• FIG. 2b shows a pressure relief valve 240 consisting of a perforated plate 250 into which one or more conventional nozzles 260 are screwed.
• a container 31 made of transparent plastic as shown in FIG. 3 was used as the pressure saturator 30. It was a 1000 mm long, vertical, 190 mm inside tube reactor. A 500 mm long dissolver tube 32, fastened at the bottom and attached to four steel rods, was suspended concentrically in the reactor, the distance between the
• a Drac-air supply was connected to the top of the pressure saturator 30, the pressure from the dedicated line being reduced to 3 bar by means of a conventional pressure reducing valve.
• a magnetic valve was connected between the drain valve and the reactor, which opened when the maximum level was reached and closed when the minimum level was reached. As a result, the pressure in the tank was almost constant at 3 bar.
• the flow of the gas flowing out of the degassing tank could be determined using a gas meter.
• the expansion nozzle 50 had a circular flow cross section of 4.7 mm in diameter at the narrowest point. At the furthest point it was
• the test arrangement was operated with a liquid throughput of 1.5 m 3 / h.
• the degree of saturation of the water achieved was 95%.
• the pressure drop across the smooth jet nozzle was 0.4 to 0.5 bar.
• the gas introduced into the expansion tank is gas bubbles which penetrate through the expansion nozzle 50 without having dissolved in the liquid.
• the transparent outer tube of the container 31 clearly showed that the liquid flowing downward in the container was clear in the lower region and thus free of bubbles. This means that the gas entered in the expansion tank could only be gas which was previously only in dissolved form and was then released again by expansion.
• Example 2 The experiment was carried out in a similar way to Example 1, except that it was not introduced into a closed degassing container, but into a round, transparent flotation cell 10 holding approximately 1 m 3 of liquid. The water released via the expansion nozzle 7 was added to the vertical inlet pipe 23 via a horizontal liquid line piece 29, as shown in FIG. 1.
• Nozzle head influences the degree of saturation achieved in the reactor.
• the exit speed was varied in the range of 6 to 11 m per second.
• the degree of saturation achieved was increased from 0.8 to 0.95 (FIG. 6).
• the degree of saturation was determined as described in Example 1 by the gas flow measured during degassing.
• Example 3 An experiment as in Example 3 was repeated, with 100 ppm of ethanol being added to the process water used for the experiment, which suppresses the coalescence of the air bubbles in water.
• the resulting very fine air bubbles have a larger surface overall than under coalescence conditions. It was found that a saturation of 0.97 to 0.98 is achieved at flow speeds at the nozzle head of 9 to 10 m / s.

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Biotechnology (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Engineering & Computer Science (AREA)
• Physical Water Treatments (AREA)
• Food Preservation Except Freezing, Refrigeration, And Drying (AREA)
• Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)

Applications Claiming Priority (3)

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• 2002
  • 2002-06-25 DE DE10228261A patent/DE10228261B3/de not_active Expired - Lifetime
• 2003
  • 2003-06-12 BR BR0312067-8A patent/BR0312067A/pt not_active Application Discontinuation
  • 2003-06-12 MX MXPA04012839A patent/MXPA04012839A/es unknown
  • 2003-06-12 AU AU2003237929A patent/AU2003237929A1/en not_active Abandoned
  • 2003-06-12 CA CA002490756A patent/CA2490756A1/en not_active Abandoned
  • 2003-06-12 JP JP2004514699A patent/JP2005530604A/ja active Pending
  • 2003-06-12 EP EP03735609A patent/EP1517743A2/de not_active Withdrawn
  • 2003-06-12 WO PCT/EP2003/006171 patent/WO2004000447A2/de active Application Filing
  • 2003-06-24 US US10/602,282 patent/US20040055941A1/en not_active Abandoned
• 2004
  • 2004-12-21 IL IL16589204A patent/IL165892A0/xx unknown

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