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
  • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
  • B03C3/02—Plant or installations having external electricity supply
  • B03C3/04—Plant or installations having external electricity supply dry type
  • B03C3/09—Plant or installations having external electricity supply dry type characterised by presence of stationary flat electrodes arranged with their flat surfaces at right angles to the gas stream
• • 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
  • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
  • B03C3/02—Plant or installations having external electricity supply
  • B03C3/16—Plant or installations having external electricity supply wet type
• • 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
  • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
  • B03C3/34—Constructional details or accessories or operation thereof
  • B03C3/40—Electrode constructions
  • B03C3/41—Ionising-electrodes
• • 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
  • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
  • B03C3/34—Constructional details or accessories or operation thereof
  • B03C3/40—Electrode constructions
  • B03C3/45—Collecting-electrodes
  • B03C3/47—Collecting-electrodes flat, e.g. plates, discs, gratings
• • 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
  • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
  • B03C3/34—Constructional details or accessories or operation thereof
  • B03C3/40—Electrode constructions
  • B03C3/45—Collecting-electrodes
  • B03C3/53—Liquid, or liquid-film, electrodes
• • 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
  • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03C2201/00—Details of magnetic or electrostatic separation
  • B03C2201/10—Ionising electrode has multiple serrated ends or parts

Definitions

• the invention relates to an ionizer in an exhaust gas purification system for drop-laden, condensing moist gases.
• the ionizer is used to charge liquid and solid particles in process gases, which is why a wet electrostatic filter or dry electrostatic precipitator is used.
• DE 101 13 582 describes a system for electrostatically cleaning gas, namely a wet electrostatic filter system.
• the system is built into the gas flow channel, in which the gas to be cleaned flows into the system from above. If the system is turned over so that the gas flow flows from bottom to top, it is observed that a water film is pushed up from the lower nozzle part to the upper nozzle part and the cross section is narrowed. This causes flashovers before the high voltage reaches such a value that sufficient ionization current can flow. This effect occurs especially with condensing and drop-laden gases at speeds of around 3 m / s from bottom to top through the nozzle. In addition, it is observed that the negatively charged center electrode bulges the water film, which hovers practically weightlessly on the edge, inwards and causes flashovers.
• No. 4,449,159 describes a conical cylinder nozzle, a so-called Venturi nozzle, which is oriented horizontally and into which the electrode is deeply immersed down to the throat.
• the electrode pin carries the ionization disk, on the circumference of which the corona current flows through the gas to the anode.
• the thicker electrode pin also serves as the focusing electrode.
• the horizontal Venturi nozzle from US Pat. No. 4,449,159 is not suitable for drip-laden, wet gas, since a film of water is always entrained in the nozzle or, at lower speeds, water drips in the throat from above onto the ionizer disc and causes flashovers.
• the disc must be adjusted very precisely to evenly distribute the current over the circumference. This is practically not possible in rough operation. Since the electrode pins have to be immersed in the nozzle, assembly is complex.
• the spray disks from US Pat. No. 4,247,307 have the task of strengthening the ionization along its circumference, while the ionization along the wire becomes smaller. Particle separation is to be improved by disks lined up along the flow direction on the wire.
• the ionizer is constructed in such a way that the nozzle plate is flowed from below and the high-voltage electrode with its pins and one star each sits in the gas stream behind it, i.e. above the nozzle plate ; this is usually the case with flue gas flows from boilers, wash columns, filters etc., before entering the chimney.
• the circular ionization streams flowing parallel from bottom to top nozzles have a diameter such that the gas velocity remains below 4 m / s, but preferably below 3 m / s.
• the height of an ionization nozzle is not significantly larger or, for the sake of simplicity, just the same size as the thickness of the nozzle plate. Except for an edge chamfer or edge rounding at the top and bottom, the nozzle has no profile in the direction of flow.
• the electrode is above the nozzle when viewed in the direction of flow. The lowest point of the electrode is still above the highest elevation of the nozzle.
• the electrode is split in a star shape at the lower end, with the star tips pointing in the direction of the nozzle circumference pointing horizontally or evenly downwards at the end. The number of peaks is greater than 1 and is preferably odd.
• the number of peaks is determined in such a way that the ionization current that can be achieved with the stable ionization voltage becomes just so large that per hour operating gas gas flowing through the nozzle has an electrical output of 0.01 to 0.5, preferably 0 , 05 to 0.3 watts is consumed.
• the distance between the tips and the edge of the nozzle is determined by the stable ionization voltage, which results from the type of gas as well as from the absolute pressure and the absolute temperature (see description of the exemplary embodiment, there the distance is 15 mm for flue gas with approx. 50 vol% water vapor at 75 ° C and 1000 mbar and 13 kV).
• vertical drainage tubes are inserted in the imaginary center of gravity of 3 nozzles in holes in the nozzle plate.
• the tubes look out about 1 to 10 plate thicknesses below the nozzle plate.
• the intake area of the tubes on the top of the nozzle plate is extended by an approximately 5 - 30 ° funnel-shaped chamfer.
• the tube preferably consists of a smooth plastic material with little wall adhesion, for example polytetrafluoroethylene, PTFE.
• the nozzle is assigned a central electrode with several tips oriented in a star shape towards the edge. This enables the nozzle for a higher gas throughput as well as for heavier ionizable gases, e.g. B. air-water vapor mixtures to operate so that the power required for particle charging can still be introduced.
• heavier ionizable gases e.g. B. air-water vapor mixtures
• the electrode star can be exchangeably attached to the end of the central electrode. If for changed operating conditions, e.g. B. other temperatures,
• the number of tips has to be adjusted, it is sufficient to replace only the electrode star. With just one electrode tip, it would have been necessary to change the number of nozzles beforehand.
• the nozzle no longer has to be milled out of a thicker plate or assembled using cylindrical, separately manufactured parts, but the slightly gripped or rounded edge of a normally drilled or water-jet cut metal plate is sufficient. Because the nozzle has no bead at the edge, liquid that collects on the top of the nozzle plate can simply drip down through the nozzle.
• the lowest point of the central electrode with the star electrode still protrudes approx. 3 - 6 mm above the upper edge of the nozzle plate. Therefore, the nozzle plate can be pulled out horizontally under the grid plate that holds the electrodes, which makes installation and removal much easier.
• the central adjustment tolerance of the central electrode is correspondingly larger due to the enlarged nozzle diameter, so that practical advantages result in particular with large-area nozzle plates. Deposits on the edge of the nozzle, due to the larger nozzle diameter, result in a smaller distortion of the current-voltage characteristic.
• the drainage tube which is inserted into the center of each nozzle between 3 nozzles, ensures that liquid that collects on the top of the plate can also drain off here.
• the inside diameter of the tube is selected so that, on the one hand, no significant amount of gas flows through in the short circuit, but on the other hand, the water that collects can run off freely.
• droplets hanging down here preferentially collect on the tube and can thus drip down the outside of the tube.
• the ionizer is used in the flow channel of a filter system together with a tube bundle separator, in such a way that it precedes it in the flow direction.
• the gas / air to be cleaned which is electrically charged in the ionizer, flows to the cone-shaped indented or bulged outflow face of the tube bundle separator after passage.
• the tube bundle separator is spatially above the ionizer and has the conical concave or convex flow face, so that the water running down the separator runs down the face towards the wall or towards the center and is directed away from there and does not drip onto the ionizer, otherwise its electrical properties would be impaired or canceled.
• the ionizer In addition to the cleaning of moist air / gas from drying processes and exhaust gases from combustion processes, the ionizer also cleans damp or natural gas displaced with drop swarms, i.e. the gas to be cleaned is already mixed with drop swarms before entering the cleaning system due to the previous usage process or is forcibly displaced by spraying through nozzles protruding into the flow channel.
• a filter system constructed in this way thus even cleans / scrubs gas / air that is mixed with gaseous pollutants, such as HC1, S0 2 , S0 3 , NOX.
• Figure 1 is a plan view of three immediately adjacent nozzles.
• Fig. 2 shows the side view
• Fig. 3 shows the seat of the ionizer in the flow channel.
• the installation of the ionizer is mechanically and insulation technology in the structure of the same as shown and described in DE 101 32 582.
• the material for the electrode depends on the gas to be processed and the components contained therein and their chemical reaction properties.
• the material can for example be copper or brass, each also covered with a protective metal, or stainless steel or titanium or alloyed titanium.
• the electrically conductive plate 4 is installed horizontally in the vertical gas duct.
• the bores 3, the nozzles, are arranged regularly, here in such a way that three immediately adjacent bores with their centers point the corners of an equilateral one Form triangle, through the triangular center of gravity is the axis of the drainage tube 6, which protrudes from the plate 8 against the stream 8 and has a funnel-shaped chamfer 7 of 30 ° on the downstream side of the nozzle plate 4 (see FIG. 2).
• the gas stream 8 flows onto this nozzle plate 4 from below and passes through the nozzles 3.
• the bores are advantageously at a uniform distance from one another or are arranged in a uniform division pattern.
• the electrode grid 5, here a gas-permeable and conductive electrode holder plate 5, is located downstream in the flow direction and above the plate 4 at a distance which is approximately one and a half to five times the bore diameter.
• the electrode holder plate 5 is fastened horizontally in the gas duct via insulators and connected to a negative high voltage compared to plate 4 (see DE 101 32 582).
• the electrode holder plate 5 When projected exactly in the center of the holes in the plate 4, the electrode holder plate 5 carries the central electrodes or electrode pins 1, which are directed downward and counter to the direction of flow toward the center of the associated nozzle 3.
• the lower end of the central electrode 1 ends approximately 0.05 to 0.2 times the nozzle bore diameter above the plate 4.
• the lower end of the respective central electrode 1 tapers or is spread out in a star shape, the individual ends at an angle project from 60 - 90 ° from the longitudinal axis of the associated electrode pin 1.
• the circle diameter, which the split ends describe as a star, is approximately 0.1 to 0.9 times the diameter of the nozzle bore.
• the number of tips is approximately the circumference of the hole in mm divided by 10 to 50 mm, so that an integer is rounded up or down. Odd numbers are preferred.
• the connection technology for the high-voltage electrode 1, 2, 5 is here a detachable one, the electrode pin 1 is screwed at one end to the electrode plate and the star 2 is free at the other.
• the dimensions here are as examples:
• a droplet separation stage according to FIG. 3 is connected downstream.
• FIG. 3 shows the ionizer stage according to FIG. 1 and accommodated in the vertical channel section 18. 2. Downstream of the flow and located above the ionizer stage, the channel section 19 is arranged, which contains an inwardly indented, conical or pyramid-shaped support grid (12 in section, 13 shown in plan view), on which there are separator pipes 16 combined into a tube bundle. The lower circumference of the support grid 12, 13 near the wall is surrounded by a drainage channel 14 with a slight slope (here to the right). This collects the drip that runs down from the pipes water, which is collected by the support grid and discharged to the duct wall 19 due to the action of gravity.
• an inwardly indented, conical or pyramid-shaped support grid (12 in section, 13 shown in plan view)
• the lower circumference of the support grid 12, 13 near the wall is surrounded by a drainage channel 14 with a slight slope (here to the right). This collects the drip that runs down from the pipes water, which is collected by the support grid and discharged to the duct wall 19
• the pyramid or cone angle ⁇ is preferably less than 90 °.
• the grid division of the support grid 12, 13 is preferably square or rectangular, the individual grid struts not running horizontally, but preferably at an angle of 45 ° to the horizontal and vertical plane.
• 8.1 is the gas, which is still heavily loaded with partially electrically charged drops, after passing through the ionizer stage.
• the clean gas largely freed from the drops and harmful gases is designated with 8.2.
• the electrical fastening of the electrode grid 5 fastened to the hanging device 10 and insulated from the gas to be processed is denoted by 11 and described elsewhere.
• the high drop concentration in the gas can be achieved in addition to the naturally existing one by feeding pure water in the flow direction upstream of the ionizer stage.
• the pure water is able to physically absorb harmful gases and vapors as in the case of e.g. B. HCl or NOx. If a soluble or insoluble basic reagent is added to the pure water, many other acidic harmful gases can also be chemically sorbed, e.g. B. S0 2 .

Applications Claiming Priority (3)

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• 2002
  • 2002-09-21 DE DE10244051A patent/DE10244051C1/de not_active Expired - Fee Related
• 2003
  • 2003-07-18 WO PCT/EP2003/007818 patent/WO2004033104A1/de active Application Filing
  • 2003-07-18 AU AU2003250987A patent/AU2003250987A1/en not_active Abandoned
  • 2003-07-18 EP EP03807751A patent/EP1539359A1/de not_active Withdrawn
  • 2003-07-18 JP JP2004542267A patent/JP4250591B2/ja not_active Expired - Fee Related
• 2005
  • 2005-01-28 US US11/046,640 patent/US7101424B2/en not_active Expired - Fee Related

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