EP0342539B1 - Elektrostatic dust separator - Google Patents

Elektrostatic dust separator Download PDF

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Publication number
EP0342539B1
EP0342539B1 EP89108577A EP89108577A EP0342539B1 EP 0342539 B1 EP0342539 B1 EP 0342539B1 EP 89108577 A EP89108577 A EP 89108577A EP 89108577 A EP89108577 A EP 89108577A EP 0342539 B1 EP0342539 B1 EP 0342539B1
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Prior art keywords
electrode
flow
dust
electrodes
deposition
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EP89108577A
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German (de)
French (fr)
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EP0342539A3 (en
EP0342539A2 (en
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Gottfried Kneifel
Sven Kneifel
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Cs Kneifel KG
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Cs Kneifel KG
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    • 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
    • B03C3/14—Plant or installations having external electricity supply dry type characterised by the additional use of mechanical effects, e.g. gravity
    • B03C3/145—Inertia
    • 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
    • B03C3/12—Plant or installations having external electricity supply dry type characterised by separation of ionising and collecting stations
    • 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
    • B03C3/51—Catch- space electrodes, e.g. slotted-box form

Definitions

  • the invention relates to an electrostatic precipitator for electrical dedusting (electrical flue gas cleaning), formed from a grounded housing, dirty gas inlet and flue gas outlet connection piece, in which in the gas flow one behind the other a high-voltage pulsating direct current preionization electrode and one or more opposite polarity from the gas flow Precipitation electrode (s) through which flow can be arranged and slide along the (s) precipitation electrode (s) solids, which discharge the dust-like particles carried in the dirty gas stream and clean the precipitation electrode.
  • a spray field is formed in the vicinity of the pre-ionization electrode. If a dust-laden flue gas stream gets into this spray field, the dust particles carried in it are ionized, which means that negative gas ions are created which negatively charge the individual dust particles. If these negatively charged dust particles enter the positively charged precipitation electrode, they are bound to it by the electric field forces. The dust particles agglomerate, which creates an increasingly thick layer that significantly reduces the effectiveness of the device.
  • the deposited dirt particles are removed by shaking, the vertically standing plate electrodes being set in vibration so that the agglomerated dust is detached.
  • the disadvantage of these devices is that complete cleaning, especially of the fine dust, is not possible. Rather, these re-enter the clean gas stream by shaking, which significantly reduces the degree of filter separation.
  • the plate electrodes are therefore mostly switched off or cleaned using special wet processes. However, this can only be done in discontinuous operation, which is considered to be very disadvantageous.
  • electrostatic filters are known in which solids flow along the precipitation electrodes and clean them. The dust-like particles are removed with the solids.
  • a solid-state bed surrounds the precipitation electrode and the bed is delimited by ring-shaped cylindrical units which are at ground potential.
  • the precipitation electrode is located in the middle of the filter bed. The field strength increases from the outside to the precipitation electrode. The highest voltage potential is therefore directly at the precipitation electrode.
  • a special position in these electrostatic filters, which are equipped with a solid, is provided by a device in which the precipitation electrode located in the middle of the filter bed is additionally cleaned by temporarily supplying it with AC voltage.
  • a disadvantage of these fixed bed electrostatic precipitators is that they also have difficulties in separating very fine dusts in grain sizes of approximately 0.001 to 0.01 mm. Due to the poor flow conditions at the precipitation electrodes, which are always in the middle of the filter bed, and the unfavorable electrical field distribution, these very fine dusts mostly return to the clean gas flow, so that the filter efficiency also drops significantly here.
  • the precipitation electrode consists of a frame which is insulated in the housing and is located on the opposite polarity to the preionization electrode.
  • This frame is formed by a cylindrical electrode, in which a wire-shaped counter electrode is housed centrally.
  • this electrostatic filter also has the disadvantages already described above.
  • the invention is therefore based on the object of avoiding the disadvantages described above, that is to provide an electrostatic filter which can be operated continuously and in which dust or dirt particles with a particle size of 0.01 to 0.001 mm are also reliably separated.
  • the precipitation electrode of such an electrostatic precipitator consists of an essentially flat-lying S-shaped inner side of a frame which is arranged in the direction of flow of the gas flow and is opposite one another at a distance from one another profiled electrode plates on which and in the space between which solids flow from an overlying pouring device to a cleaning and regeneration unit arranged below.
  • the solids should have a diameter of approximately between 3 mm and 8 mm.
  • the entire precipitation electrode is therefore under voltage with a potential opposite to the pre-ionization electrode.
  • the flue gas stream flows through this precipitation electrode, this flue gas stream entering the S-shaped profiled electrode sheets on the one hand, passing between these electrode sheets into the free space between the opposing S-shaped profiled electrode sheets, and then S-shaped on the other side profiled electrode sheets emerges from the precipitation electrode.
  • a dirty gas inlet connector for introducing the dirty gas flow (9) and on the other side a smoke gas outlet connector for removing the cleaned smoke gas (6).
  • a pre-ionization electrode (3) and a precipitation electrode (13) are accommodated on insulators (4) in the interior of the housing (8).
  • the precipitation electrode is formed from S-shaped electrode sheets (1) arranged in a frame (2), between which a fixed bed stream consisting of fixed bed bodies flows from an overhead pouring device (7) to a collecting container (10) located below. Below the collecting container (10) there is a cleaning and regeneration unit (11) which frees the fixed bed body from adhering dirt and dust and regenerates it for reuse. From there, the fixed bed bodies get back into the pouring device (7) by a lifting device (not shown).
  • the S-shaped profiled electrode sheets (1) are housed flat in the frame (2) and, as indicated by the markings (x) or as shown in Fig.3, the flue gas flows through them.
  • the S-shaped electrode sheets (1) arranged in the frame (2) on its inner sides enclose a space (5) between them, which the fixed bed moves from above can hike down below.
  • the S-shaped profiled electrode sheets (1) are connected to a positive voltage between 1,500 and 4,000 V; the pre-ionization electrode has a potential of approximately minus 50,000 V (50 kV). This voltage potential between the two electrodes and the resulting electrical field strengths cause the pre-ionized dust particles to adhere to the electrode sheets (1) and the ionized solids.
  • the specially designed Newtonian fluid of the solid body firstly cleans the S-shaped electrode plates (1) and the solid particles of the edge zone (12), which are heavily loaded. Due to the special flow conditions in the middle of the precipitation electrode (13), solids and dust particles are removed to the cleaning and regeneration unit (11).
  • FIG. 4 shows the flow conditions of the solid bed again as quasi Newtonian fluid.
  • the solids which have an irregular shape, are under the weight (F N ).
  • the static force sigma at right angles to the weight also acts on them.
  • the solid current between the S-shaped profiled electrode sheets (1) has the speed (v1), in the edge zone (12) the speed (v2).
  • This different speed or the relative speeds between v1 and v2 result in different rotational speeds (v rot ).
  • the solids located at the edge zone rotate faster (v rot2 ) than those towards the center of the fixed bed flow .
  • the shear stress tau which results from the static pressure sigma together with the shape of the S-shaped profile of the electrode sheet (1), is also shown in FIG.

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  • Electrostatic Separation (AREA)
  • Filtering Materials (AREA)
  • Elimination Of Static Electricity (AREA)
  • Luminescent Compositions (AREA)
  • Detergent Compositions (AREA)

Abstract

The known electrostatic filters operate either only discontinuously or ineffectively, since they are not capable of retaining fine or very fine dust particles. A continuous operation in which even very fine dust particles are retained is obtained in a manner according to the invention by means of a collecting electrode, arranged in such an electrostatic filter, with flat-lying S-shaped profiled electrode plates, between which a stream of solids flows through. <IMAGE>

Description

Die Erfindung betrifft einen Elektrofilter zur Elektroentstaubung (Elektro-Rauchgasreinigung), gebildet aus einem an Masse liegenden Gehäuse, Schmutzgaseintritts- und Rauchgasaustritts-Stutzen, in dem im Gasstrom hintereinander eine an hochgespanntem pulsierenden Gleichstrom liegende Vorionisationselektrode und eine oder mehrere an entgegensetzter Polarität liegende vom Gasstrom durchströmbare Niederschlagselektrode(n) angeordnet sind und an der (den) Niederschlagselektrode(n) Festkörper entlanggleiten, die die im Schmutzgasstrom mitgeführten staubförmigen Partikel austragen und die Niederschlagselektrode reinigen.The invention relates to an electrostatic precipitator for electrical dedusting (electrical flue gas cleaning), formed from a grounded housing, dirty gas inlet and flue gas outlet connection piece, in which in the gas flow one behind the other a high-voltage pulsating direct current preionization electrode and one or more opposite polarity from the gas flow Precipitation electrode (s) through which flow can be arranged and slide along the (s) precipitation electrode (s) solids, which discharge the dust-like particles carried in the dirty gas stream and clean the precipitation electrode.

Infolge des auf minus 50 kV hochgespannten pulsierenden Gleichstromes bildet sich in der Umgebung der Vorionisationselektrode ein Sprühfeld aus. Gelangt ein staubbeladener Rauchgasstrom in dieses Sprühfeld, so werden die in ihm mitgeführten Staubteilchen ionisiert, das heißt, es entstehen negative Gasionen, die die einzelnen Staubteilchen negativ aufladen. Treten nun diese negativ aufgeladenen Staubteilchen in die positiv geladene Niederschlagselektrode ein, werden sie durch die elektrischen Feldkräfte an diese gebunden. Dabei agglomerieren die Staub- partikel, wodurch eine immer dicker werdende Schicht entsteht, die die Effektivität der Einrichtung deutlich vermindert.As a result of the pulsating direct current being raised to minus 50 kV, a spray field is formed in the vicinity of the pre-ionization electrode. If a dust-laden flue gas stream gets into this spray field, the dust particles carried in it are ionized, which means that negative gas ions are created which negatively charge the individual dust particles. If these negatively charged dust particles enter the positively charged precipitation electrode, they are bound to it by the electric field forces. The dust particles agglomerate, which creates an increasingly thick layer that significantly reduces the effectiveness of the device.

Bei den bekannten Elektro-Plattenfiltern geschieht das Entfernen der abgelagerten Schmutzpartikel durch Rütteln, wobei die vertikal stehenden Platten-Elektroden so in Schwingung versetzt werden, daß ein Ablösen des agglomerierten Staubes erfolgt. Nachteilig ist bei diesen Einrichtungen, daß eine vollständige Abreinigung, insbesondere der Feinstäube, nicht möglich ist. Diese treten durch das Abrütteln vielmehr wieder in den Reingasstrom ein, wodurch der Filterabscheidegrad erheblich sinkt. Um diesem Nachteil zu begegnen, beziehungsweise um eine vollständige Reinigung der Elektroden zu erhalten, werden daher die Plattenelektroden zumeist abgeschaltet oder über spezielle Naß-Verfahren gereinigt. Dies kann allerdings nur im diskontinuierlichen Betrieb, der als sehr nachteilig angesehen wird, erfolgen.In the known electric plate filters, the deposited dirt particles are removed by shaking, the vertically standing plate electrodes being set in vibration so that the agglomerated dust is detached. The disadvantage of these devices is that complete cleaning, especially of the fine dust, is not possible. Rather, these re-enter the clean gas stream by shaking, which significantly reduces the degree of filter separation. In order to counter this disadvantage, or to obtain complete cleaning of the electrodes, the plate electrodes are therefore mostly switched off or cleaned using special wet processes. However, this can only be done in discontinuous operation, which is considered to be very disadvantageous.

Des weiteren sind Elektrofilter bekannt, bei denen Festkörper an den Niederschlagselektroden entlangströmen und diese reinigen. Mit den Festkörpern werden die staubförmigen Partikel ausgetragen. Gemeinsam ist diesen Einrichtungen, daß ein Festkörperbett die Niederschlagselektrode umgibt und das Bett durch ringförmige zylindrische Einheiten, welche auf Massepotential liegen, begrenzt sind. Die Niederschlagselektrode befindet sich hierbei inmitten des Filterbettes. Damit nimmt die Feldstärke von außen her bis zur Niederschlagselektrode hin zu. Das höchste Spannungspotential liegt also direkt an der Niederschlagselektrode.Furthermore, electrostatic filters are known in which solids flow along the precipitation electrodes and clean them. The dust-like particles are removed with the solids. Common to these devices is that a solid-state bed surrounds the precipitation electrode and the bed is delimited by ring-shaped cylindrical units which are at ground potential. The precipitation electrode is located in the middle of the filter bed. The field strength increases from the outside to the precipitation electrode. The highest voltage potential is therefore directly at the precipitation electrode.

Eine Sonderstellung bei diesen mit einem Festkörper ausgestatteten Elektrofiltern nimmt eine Einrichtung ein, bei der die inmitten des Filterbettes liegende Niederschlagselektrode durch zeitweise Speisung mit Wechselspannung zusätzlich gereinigt wird. Hierbei werden die negativ ionisierten Staubteilchen, die sich durch die umgekehrte Polarität an der Niederschlagselektrode angesetzt haben, durch die Wechselspannung von der Niederschlagselektrode losgelöst und sodann von dem Festkörper-Filterbett ausgetragen.A special position in these electrostatic filters, which are equipped with a solid, is provided by a device in which the precipitation electrode located in the middle of the filter bed is additionally cleaned by temporarily supplying it with AC voltage. Here, the negatively ionized Dust particles that have accumulated on the precipitation electrode due to the reverse polarity, detached from the precipitation electrode by the AC voltage and then discharged from the solid-state filter bed.

Als Nachteil ist bei diesen Festbett-Elektrofiltern wiederum festzustellen, daß auch bei Ihnen Schwierigkeiten bei der Abscheidung von Feinststäuben in Korngrößen von etwa 0,001 bis 0,01 mm auftreten. Diese Feinststäube gelangen durch die schlechten Strömungsverhältnisse an den stets inmitten des Filterbettes befindlichen Niederschlagselektroden und die ungünstige elektrische Feldverteilung zumeist wieder in den Reingasstrom zurück, sodaß auch hier der Filterwirkungsgrad deutlich absinkt.A disadvantage of these fixed bed electrostatic precipitators is that they also have difficulties in separating very fine dusts in grain sizes of approximately 0.001 to 0.01 mm. Due to the poor flow conditions at the precipitation electrodes, which are always in the middle of the filter bed, and the unfavorable electrical field distribution, these very fine dusts mostly return to the clean gas flow, so that the filter efficiency also drops significantly here.

Weiter bekannt, nach der WO 81/00 524, ist ein Elektrofilter, bei dem die Niederschlagselektrode aus einem im Gehäuse isoliert angeordneten, an der zur Vorionisationselektrode entgegengesetzten Polarität liegenden Rahmen besteht. Dieser Rahmen wird durch eine zylindrische Elektrode gebildet, in der zentral eine drahtförmige Gegenelektrode untergebracht ist. Auch diesem Elektrofilter hängen jedoch die oben bereits beschriebenen Nachteile an.Also known, according to WO 81/00 524, is an electrostatic filter, in which the precipitation electrode consists of a frame which is insulated in the housing and is located on the opposite polarity to the preionization electrode. This frame is formed by a cylindrical electrode, in which a wire-shaped counter electrode is housed centrally. However, this electrostatic filter also has the disadvantages already described above.

Der Erfindung liegt damit die Aufgabe zugrunde, die vorstehend beschriebenen Nachteile zu vermeiden, also einen Elektrofilter anzugeben, der kontinuierlich betrieben werden kann und bei dem auch Staub beziehungsweise Schmutzteilchen einer Korngröße von 0,01 bis 0,001 mm zuverlässig abgeschieden werden. Erreicht wird dies nach der Erfindung dadurch, daß die Niederschlagselektrode eines derartigen Elektrofilters aus in einem in Durchströmungsrichtung des Gasstroms gegenüberliegenden Innenseiten eines Rahmens angeordneten, mit Abstand voneinander gegeneinander gerichteten, im wesentlichen flachliegenden S-förmig profilierten Elektrodenblechen besteht, auf denen und in dem Raum zwischen denen Festkörper von einer darüber angeordneten Schüttvorrichtung zu einer darunter angeordneten Reinigungs- und Regenerierungseinheit fließen. Hierbei sollen die Festkörper einen etwa zwischen 3 mm und 8 mm liegenden Durchmesser aufweisen.The invention is therefore based on the object of avoiding the disadvantages described above, that is to provide an electrostatic filter which can be operated continuously and in which dust or dirt particles with a particle size of 0.01 to 0.001 mm are also reliably separated. This is achieved according to the invention in that the precipitation electrode of such an electrostatic precipitator consists of an essentially flat-lying S-shaped inner side of a frame which is arranged in the direction of flow of the gas flow and is opposite one another at a distance from one another profiled electrode plates on which and in the space between which solids flow from an overlying pouring device to a cleaning and regeneration unit arranged below. The solids should have a diameter of approximately between 3 mm and 8 mm.

Bei der erfindungsgemäßen Einrichtung steht demnach die gesamte Niederschlagselektrode unter Spannung mit einem, zu der Vorionisationselektrode entgegengesetzten Potential. Außerdem wird diese Niederschlagselektrode von dem Rauchgasstrom durchströmt, wobei dieser Rauchgasstrom einerseits bei den S-förmig profilierten Elektrodenblechen eintritt, zwischen diesen Elektrodenblechen hindurch in den freien Raum zwischen den gegenüber stehenden S-förmig profilierten Elektrodenblechen gelangt und sodann bei den jenseits angeordneten wiederum S-förmig profilierten Elektrodenblechen aus der Niederschlagselektrode austritt. Dadurch entsteht ein Effekt, der noch bei keinem derartigen Elektrofilter bekannt wurde, nämlich, daß sich die im Rauchgasstrom mitgeführten Staubpartikel zum größten Teil eingangsseitig an den dortigen S-förmig profilierten Elektrodenblechen beziehungsweise an den Festbettkörperchen ablagern, daß aber sodann ausgangsseitig eine nochmalige Nachreinigung stattfindet, bei der insbesondere die Fein- und Feinststäube aus dem Rauchgasstrom an den ausgangsseitigen wiederum S-förmigen Elektrodenblechen ausgeschieden werden. Insbesondere ist dies der Feldverteilung innerhalb der Niederschlagselektrode zu verdanken, die ja eingangs- und ausgangsseitig die höchste Feldstärke aufweist.In the device according to the invention, the entire precipitation electrode is therefore under voltage with a potential opposite to the pre-ionization electrode. In addition, the flue gas stream flows through this precipitation electrode, this flue gas stream entering the S-shaped profiled electrode sheets on the one hand, passing between these electrode sheets into the free space between the opposing S-shaped profiled electrode sheets, and then S-shaped on the other side profiled electrode sheets emerges from the precipitation electrode. This creates an effect that has not yet been known for any such electrostatic precipitator, namely that the dust particles carried in the flue gas stream are mostly deposited on the input side on the S-shaped electrode sheets there or on the fixed bed body, but that a subsequent subsequent cleaning then takes place on the output side. in which in particular the fine and ultra-fine dusts are separated from the flue gas flow on the outlet-side S-shaped electrode plates. This is due in particular to the field distribution within the precipitation electrode, which has the highest field strength on the input and output side.

Äußerst bedeutsam und noch bei keiner derartigen Einrichtung bekannt ist die Ausführung der durchströmten Niederschlagselektrode, mit den in dem Rahmens angeordneten S-förmig profilierten Elektrodenblechen auf denen und zwischen denen die Festkörper "fließen". In der Ausführung der S-förmig profilierten Elektrodenbleche liegt konkrete Forschungsarbeit. Sie sind so berechnet und in Versuchsreihen so optimiert worden, daß der durch die Niederschlagselektrode führende Festbettstrom ein quasi Newton'sches Fluid bildet. Hierbei wurde erreicht, daß die Festkörperteilchen Rotationsarbeit leisten, die sich aus dem Differential der Coulomb-Reibung und dem Differential der Arbeit der Stoßvorgänge im Festkörperbett zusammensetzen. Durch die Form der Elektrodenbleche bedingt tritt am Rande der Bleche für die Festkörper eine Schubspannung auf, die wiederum eine spezielle Rotation der Festkörper zur Folge hat. Dadurch wird folgendes erreicht:

  • 1. Die Festkörper, insbesondere diejenigen der Randzone, vergrößern ihre schmutzaufnehmende Oberfläche durch die Rotation um etwa 40%. Daraus ergibt sich eine gute Abscheidung an den Stellen, die vom Staub besonders stark belastet sind.
  • 2. Durch unterschiedliche Relativgeschwindigkeiten der Festbettkörperchen folgen unterschiedliche Rotationsgeschwindigkeiten, was zur Folge hat, daß die Festkörper der Randzone sehr schnell von anhaftendem Staub befreit werden. Die Festkörper in der Mitte des Festkörperbettes jedoch rotieren nur in sehr geringem Maße, sodaß dort der Staub gut haften kann und damit mit den Festkörpern sicher abtransportiert wird.
The design of the flow-through precipitation electrode, with those arranged in the frame, is extremely important and is not yet known in any such device S-shaped profiled electrode sheets on and between which the solids "flow". Specific research work has been carried out in the execution of the S-shaped profiled electrode sheets. They have been calculated and optimized in series of tests so that the fixed bed current leading through the precipitation electrode forms a quasi Newtonian fluid. It was achieved that the solid particles perform rotational work, which are composed of the differential of the Coulomb friction and the differential of the work of the impact processes in the solid bed. Due to the shape of the electrode plates, a shear stress occurs at the edge of the plates for the solid bodies, which in turn results in a special rotation of the solid bodies. This achieves the following:
  • 1. The solids, especially those in the peripheral zone, increase their dirt-absorbing surface by the rotation by about 40%. This results in a good separation in the places that are particularly heavily polluted by dust.
  • 2. Due to different relative speeds of the fixed bed bodies, different rotational speeds follow, which has the consequence that the solid bodies of the peripheral zone are very quickly freed of adhering dust. The solids in the middle of the solid bed, however, rotate only to a very small extent, so that the dust can adhere well there and is therefore safely transported away with the solids.

Insgesamt ergibt sich damit ein Elektrofilter, der wie gefordert kontinuierlich betrieben werden kann und nicht nur höchst effektiv ist, sondern auch Fein- und Feinststäube sicher aus dem Rauchgasstrom aufnimmt.Overall, this results in an electrostatic precipitator that can be operated continuously as required and is not only extremely effective, but also reliably absorbs fine and fine dust from the flue gas stream.

Auf der Zeichnung ist ein Ausführungsbeispiel des Elektrofilters nach der Erfindung schematisch dargestellt und zwar zeigen

  • Fig.1 den Elektrofilter in Ansicht, teilweise geschnitten,
  • Fig.2 den Feldstärkeverlauf,
  • Fig.3 einen Schnitt durch die Niederschlagselektrode und
  • Fig.4 eine Teilansicht bei den S-förmig profilierten Elektrodenblechen.
In the drawing, an embodiment of the electrostatic filter according to the invention is shown schematically and that show
  • 1 shows the electrostatic filter in a view, partly in section,
  • 2 shows the field strength curve,
  • 3 shows a section through the precipitation electrode and
  • 4 shows a partial view of the S-shaped profiled electrode sheets.

An einem Gehäuse (8) ist einerseits ein Schmutzgaseintrittsstutzen zum Einführen des Schmutzgasstromes (9) und jenseits ein Rauchgasaustrittsstutzen zum Abführen des gereinigten Rauchgases (6) angebracht. Im Innern des Gehäuses (8) sind auf Isolatoren (4) eine Vorionisationselektrode (3) und eine Niederschlagselektrode (13) untergebracht. Die Niederschlagselektrode wird gebildet aus in einem Rahmen (2) angeordneten S-förmig profilierten Elektrodenblechen (1), zwischen denen ein aus Festbettkörperchen bestehender Festbettstrom von einer oben liegenden Schüttvorrichtung (7) zu einem unten liegenden Sammelbehälter (10) hindurch strömt. Unterhalb des Sammelbehälters (10) befindet sich eine Reinigungs- und Regenerie rungseinheit (11), die die Festbettkörper von anhaftendem Schmutz und Staub befreit und zur Wiederverwendung regeneriert. Von dortaus gelangen die Festbettkörper durch eine (nicht eingezeichnete) Hebevorrichtung wieder in die Schüttvorrichtung (7).On a housing (8), on the one hand, a dirty gas inlet connector for introducing the dirty gas flow (9) and on the other side a smoke gas outlet connector for removing the cleaned smoke gas (6). A pre-ionization electrode (3) and a precipitation electrode (13) are accommodated on insulators (4) in the interior of the housing (8). The precipitation electrode is formed from S-shaped electrode sheets (1) arranged in a frame (2), between which a fixed bed stream consisting of fixed bed bodies flows from an overhead pouring device (7) to a collecting container (10) located below. Below the collecting container (10) there is a cleaning and regeneration unit (11) which frees the fixed bed body from adhering dirt and dust and regenerates it for reuse. From there, the fixed bed bodies get back into the pouring device (7) by a lifting device (not shown).

Die S-förmig profilierten Elektrodenbleche (1) sind flachliegend in dem Rahmen (2) untergebracht und werden, wie durch die Markierungen (x) angedeutet, beziehungsweise wie in Fig.3 gezeigt, vom Rauchgas durchströmt. Die in den Rahmen (2) an seinen Innenseiten angeordneten S-förmig profilierten Elektrodenbleche (1) schließen zwischen sich einen Raum (5) ein, den das Festbett von oben nach unten durchwandern kann. Die S-förmig profilierten Elektrodenbleche (1) liegen hierbei an einer positiven Spannung zwischen 1.500 und 4.000 V; die Vorionisationselektrode weist ein Potential von etwa minus 50.000 V (50 kV) auf. Durch dieses Spannungspotential zwischen den beiden Elektroden beziehungsweise durch die sich hierbei ergebenden elektrischen Feldstärken lagern sich die vorionisierten Staubteilchen an den Elektrodenblechen (1) und den ionisierten Festkörpern an.The S-shaped profiled electrode sheets (1) are housed flat in the frame (2) and, as indicated by the markings (x) or as shown in Fig.3, the flue gas flows through them. The S-shaped electrode sheets (1) arranged in the frame (2) on its inner sides enclose a space (5) between them, which the fixed bed moves from above can hike down below. The S-shaped profiled electrode sheets (1) are connected to a positive voltage between 1,500 and 4,000 V; the pre-ionization electrode has a potential of approximately minus 50,000 V (50 kV). This voltage potential between the two electrodes and the resulting electrical field strengths cause the pre-ionized dust particles to adhere to the electrode sheets (1) and the ionized solids.

Durch das speziell ausgebildete Newton'sche Fluid der Festkörper werden zum einen die S-förmig profilierten Elektrodenbleche (1) und die Festkörperteilchen der Randzone (12), welche stark belastet sind, gereinigt. Durch die speziellen Strömungsverhältnisse inmitten der Niederschlagselektrode (13) werden Festkörper und Staubpartikel zur Reinigungs- und Regenerierungseinheit (11) abtransportiert.The specially designed Newtonian fluid of the solid body firstly cleans the S-shaped electrode plates (1) and the solid particles of the edge zone (12), which are heavily loaded. Due to the special flow conditions in the middle of the precipitation electrode (13), solids and dust particles are removed to the cleaning and regeneration unit (11).

In Fig.4 sind die Strömungsverhältnisse des Festkörperbettes als quasi Newton'sches Fluid nochmals dargestellt. Die Festkörperchen, die eine unregelmäßige Form aufweisen, stehen unter der Gewichtskraft (FN). Weiter wirkt auf sie die rechtwinklig zu der Gewichtskraft liegende statische Kraft sigma. Der Festkörperstrom zwischen den S-förmig profilierten Elektrodenblechen (1) weist die Geschwindigkeit (v1), in der Randzone (12) die Geschwindigkeit (v2) auf. Durch diese unterschiedliche Geschwindigkeit beziehungsweise die Relativgeschwindigkeiten zwischen v1 und v2 folgen unterschiedliche Rotationsgeschwindigkeiten (vrot). Dies hat zur Folge, daß die an der Randzone befindlichen Festkörper schneller rotieren (vrot2) als diejenigen zur Mitte des Festbettstromes hin. Dadurch ergibt sich der erwünschte Effekt, daß die Festkörper der Randzone (12) schneller von anhaftendem Staub und Schmutz befreit werden, während die Festkörper innerhalb des Festbettstromes, also die Festkörper, die sich im Raum (5) befinden, den Schmutz und Staub sicher nach unten zur Reinigungs- und Regenerierungseinheit (11) befördern.4 shows the flow conditions of the solid bed again as quasi Newtonian fluid. The solids, which have an irregular shape, are under the weight (F N ). The static force sigma at right angles to the weight also acts on them. The solid current between the S-shaped profiled electrode sheets (1) has the speed (v1), in the edge zone (12) the speed (v2). This different speed or the relative speeds between v1 and v2 result in different rotational speeds (v rot ). As a result, the solids located at the edge zone rotate faster (v rot2 ) than those towards the center of the fixed bed flow . This results in the desired effect that the solids of the edge zone (12) more quickly from adhering Dust and dirt are freed, while the solids within the fixed bed flow, that is to say the solids which are in the room (5), convey the dirt and dust down to the cleaning and regeneration unit (11).

Eingezeichnet in Fig.4 ist auch die Schubspannung tau, die sich aus dem statischen Druck sigma zusammen mit der Form des S-förmigen Profils der Elektrodenbleehe (1) ergibt.The shear stress tau, which results from the static pressure sigma together with the shape of the S-shaped profile of the electrode sheet (1), is also shown in FIG.

Claims (2)

1. An electrostatic filter for the electrostatic removal of dust, formed from an earthed housing (8) with dirty gas intake (9) and flue gas outlet connections (6) and in which there are arranged in succession in the flow of gas passing therethrough a pre-ionisation electrode (3) which is connected to a high-tension pulsating direct current and one or more deposition electrodes (3) through which the gas flow can pass and which are at a polarity opposite to said pre-ionisation electrode (3) and which comprise a frame (2) arranged insulatedly in the housing (8), and solid bodies which are slidable along the deposition electrode or electrodes (13) and which carry out the dust particles entrained in the dirty gas flow, and clean the deposition electrode or electrodes (13), characterised in that the deposition electrode (13) comprises electrode plates (1) which lie substantially flat and which are of a substantially S-shaped profile and which are directed opposite to each other at a spacing from each other and which are arranged at the insides of the frame (2) which are opposite to each other in the direction of flow of the gas flow therethrough, solid bodies flowing on the electrode plates and in the space between them from a charging device (7) arranged thereabove to a cleaning and regenerating unit (11) arranged therebeneath.
2. An electrostatic filter according to claim 1 characterised in that the solid bodies are of a diameter of between 3 mm and 8 mm.
EP89108577A 1988-05-14 1989-05-12 Elektrostatic dust separator Expired - Lifetime EP0342539B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89108577T ATE73017T1 (en) 1988-05-14 1989-05-12 ELECTROSTATIC DUST COLLECTOR.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3816525 1988-05-14
DE3816525 1988-05-14

Publications (3)

Publication Number Publication Date
EP0342539A2 EP0342539A2 (en) 1989-11-23
EP0342539A3 EP0342539A3 (en) 1990-05-09
EP0342539B1 true EP0342539B1 (en) 1992-03-04

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Application Number Title Priority Date Filing Date
EP89108577A Expired - Lifetime EP0342539B1 (en) 1988-05-14 1989-05-12 Elektrostatic dust separator

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EP (1) EP0342539B1 (en)
AT (1) ATE73017T1 (en)
DE (1) DE58900899D1 (en)
ES (1) ES2029914T3 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2343387B (en) * 1998-10-20 2001-02-28 Jeffrey Carl Alexander Electrostatically controlled process for contacting of gases and solid particles

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE749624C (en) * 1937-10-09 1944-11-27 Trap precipitation electrode for electric gas cleaners
DE2340716A1 (en) * 1972-11-02 1975-02-20 8601 Steinfeld DEVICE FOR ELECTRONIC DUST SEPARATION
US4308036A (en) * 1979-08-23 1981-12-29 Efb Inc. Filter apparatus and method for collecting fly ash and fine dust

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DE58900899D1 (en) 1992-04-09
EP0342539A3 (en) 1990-05-09
EP0342539A2 (en) 1989-11-23
ES2029914T3 (en) 1992-10-01
ATE73017T1 (en) 1992-03-15

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