EP0210675B1 - Control method for an electrostatic filter - Google Patents

Control method for an electrostatic filter Download PDF

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Publication number
EP0210675B1
EP0210675B1 EP86201035A EP86201035A EP0210675B1 EP 0210675 B1 EP0210675 B1 EP 0210675B1 EP 86201035 A EP86201035 A EP 86201035A EP 86201035 A EP86201035 A EP 86201035A EP 0210675 B1 EP0210675 B1 EP 0210675B1
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Prior art keywords
characteristic
voltage
recorded
value
electrostatic precipitator
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German (de)
French (fr)
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EP0210675A1 (en
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Wilhelm Leussler
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GEA Group AG
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Metallgesellschaft AG
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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
    • B03C3/34—Constructional details or accessories or operation thereof
    • B03C3/66—Applications of electricity supply techniques
    • B03C3/68—Control systems therefor

Definitions

  • the invention relates to a method for operating an electrostatic precipitator with the lowest possible energy consumption for a given clean gas dust content by regulating the operating voltage by means of semipulses.
  • an electrostatic filter in which dust is separated by applying a DC high voltage that can be regulated by means of a thyristor between the precipitation electrodes and the spray electrodes.
  • a control circuit for intermittently actuating the thyristor is provided, by means of which the repetition period and / or the pulse width of the direct current high voltage can be set manually or automatically.
  • the separation performance of the electrostatic filter is to be improved, in particular in the case of a high specific dust resistance in the range from 1011 to 10 ⁇ m ⁇ cm, in which an electrostatic filter normally only works unsatisfactorily as a result of counter-corona effects.
  • the thyristor is driven in such a way that the DC high voltage is applied during a first phase Ti (from, for example, 0.001 to 1 s) and interrupted during a second phase T 2 (from, for example, 0.01 to 1 s) .
  • the expression k-value is used for the ratio of Ti to (T 1 + T 2 ), that is to say from the on-time to the on-time and pause time of each switching cycle, and for the entire method "regulation by means of semipulses".
  • the known method aims in particular to avoid a counter-corona effect, which is characterized in the current-voltage map by a comparatively very steep increase in the current with only a slight increase in the voltage. With such characteristics, high energy consumption is associated with low dust removal performance of the electrostatic filter.
  • the method of semipulsing since the occurrence of the counter-corona effect occurs with a certain delay compared to an increase in the voltage or the current caused by the usual regulation, it is possible with the method of semipulsing to largely avoid the counter-corona effects and to operate the electrostatic filter economically to reach.
  • the measures according to DE-OS 3114 009 are therefore aimed at achieving optimum separation performance even in the area of high specific dust resistances.
  • the characteristic diagram is created either when an electrostatic filter is started up or on the basis of empirical values. It is also provided that the map is continuously corrected using the current characteristic curves determined during operation. The setting of the k value according to measure d) in claim 1 is repeated at predetermined time intervals. Finally, it is provided in the method according to the invention that all method steps run completely automatically.
  • the energy is fed into the electrostatic filter according to FIG. 1 via two antiparallel connected Thyristo ren 1, a high voltage transformer 3 and a rectifier 4.
  • the precipitation electrodes are like the filter housing 7 to earth 8, while the spray electrodes are connected to the negative pole of the high voltage source.
  • the primary current of the high-voltage transformer 3 is measured by means of a current transformer 2.
  • the secondary or filter current is determined via a shunt 5, while the secondary or filter voltage is measured via a measuring bridge 6a, 6b.
  • the measured values (from 2, 5, 6a and 6b) are fed to an electronic control device 9, which generates the pulses for firing the thyristor 1.
  • the control device 9 works fully automatically; it monitors the current and prevents the nominal current from being exceeded; it monitors the voltage and ensures that the voltage used is as close as possible to the breakdown voltage, that the voltage is reduced in the event of flashovers and that the system is switched off in the event of a permanent short circuit.
  • a microcomputer 10 is provided in which the digitized characteristics of the filter with the associated k values are stored. At predetermined intervals, the current current-voltage characteristic curve of the filter is recorded via the control device 9, compared with the stored characteristic curves and a new k value passed on to the control device if a more favorable k value has resulted from the comparison of the characteristic curves.
  • the characteristic values recorded under different operating conditions are each assigned the k values with which a predetermined clean gas dust content can be maintained with the least possible energy expenditure. Since the measurement and calculation processes run very quickly, there is no deterioration in the degree of separation during the recording of a new characteristic. Since modern electrostatic precipitators generally also have several filters connected in series, which are checked and optimized in succession in the manner described, even strongly and rapidly changing changes in the operating states can be compensated for while maintaining the energy consumption optimization without exceeding the predetermined clean gas dust contents.
  • the repetition intervals can be set between a few minutes and hours, depending on whether, like the dedusting of steel converters, there are rapidly changing operating states or only minor and slow changes, such as the dedusting of the boiler exhaust gases from power plants.
  • FIG. 3 shows the secondary current of the rectifier 4 or the filter current during a pulse operation according to FIG. 1. Every two pulses are followed by an unpowered time of twice the pulse time.
  • Fig. 4 shows the voltage applied to the electrostatic filter. Since the filter acts as a capacitor, the voltage does not go back to zero after pulsing, but to a more or less high "residual value". When pulsing again, it is raised again to the maximum value.
  • Fig. 5 shows the characteristic field of a filter, i.e. the current consumed as a function of the applied voltage for various operating states. The latter are determined by the gas temperature, the gas composition, the dust resistance and by a number of other influencing factors. According to the invention, the various characteristic curves have been assigned the k-values which have to be used if the specified clean gas dust content is to be achieved with the least possible energy expenditure.
  • the other two characteristics relate to dust resistance in between.
  • the following can be seen from the assignment of the k values to the characteristic curves. While the specified clean gas dust content is best achieved with a low-pulsation method at low dust resistances, the same goal is achieved with very high dust resistances if the pause time is, for example, 9 times as long as the pulse time T i , i.e. if only during a 1/10 the time is pulsed.
  • the characteristic curves between the k values 1 and 0.1 are particularly interesting and need to be optimized because the dust resistance is in many cases between 1011 and 10 13 Q cm and a repeated, precise adjustment to the current conditions is particularly important and worthwhile.

Abstract

Disclosed is a method for the operation of an electrostatic precipitator so as to provide a pure gas having a predetermined dust content with a minimum consumption of energy. Characteristics for the operation with an unpulsed voltage are recorded for different dust resistivities. Each characteristic has then associated with it that k value with which a pure gas having a predetermined dust can be achieved with a minimum energy consumption. During operation, the actual characteristic is compared with the recorded characteristics and that k value is selected which is associated with the recorded characteristic which coincides with the actual characteristic or is next below the actual characteristic. The actual characteristic is determined in predetermined intervals, the duration of which is determined in dependence on the speed with which the operating conditions may be expected to change.

Description

Die Erfindung bezieht sich auf ein Verfahren zum Betreiben eines Elektrofilters mit kleinstmöglichem Energieaufwand bei vorgegebenem Reingasstaubgehalt durch Regelung der Betriebsspannung mittels Semipulsen.The invention relates to a method for operating an electrostatic precipitator with the lowest possible energy consumption for a given clean gas dust content by regulating the operating voltage by means of semipulses.

Aus der DE-OS 31 14 009 ist ein Elektrofilter bekanntgeworden, bei dem die Staubabscheidung dadurch erfolgt, daß zwischen den Niederschlagselektroden und den Sprühelektroden eine mittels Thyristor regelbare Gleichstrom-Hochspannung angelegt wird. Außerdem ist eine Steuerschaltung zur intermittierenden Ansteuerung des Thyristors vorgesehen, durch die die Wiederholungsperiode und/oder die Impulsbreite der Gleichstromhochspannung manuell oder automatisch einstellbar ist. Mit einer derartigen Steuerschaltung soll die Abscheideleistung des Elektrofilters insbesondere bei hohem spezifischen Staubwiderstand im Bereich von 1011 bis 10is ß cm verbessert werden, in dem ein Elektrofilter normalerweise infolge von Gegen-Koronaeffekten nur unbefriedigend arbeitet.From DE-OS 31 14 009, an electrostatic filter has become known, in which dust is separated by applying a DC high voltage that can be regulated by means of a thyristor between the precipitation electrodes and the spray electrodes. In addition, a control circuit for intermittently actuating the thyristor is provided, by means of which the repetition period and / or the pulse width of the direct current high voltage can be set manually or automatically. With such a control circuit, the separation performance of the electrostatic filter is to be improved, in particular in the case of a high specific dust resistance in the range from 1011 to 10 μm β cm, in which an electrostatic filter normally only works unsatisfactorily as a result of counter-corona effects.

Bei der bekannten Steuerschaltung wird der Thyristor in der Weise angesteuert, daß die Gleichstrom-Hochspannung während einer ersten Phase Ti (von beispielsweise 0,001 bis 1 s) angelegt und während einer zweiten Phase T2 (von beispielsweise 0,01 bis 1 s) unterbrochen wird. Für das Verhältnis von Ti zu (T1 + T2), also von Einschaltzeit zu Einschalt- und Pausenzeit eines jeden Schaltzyklus ist der Ausdruck k-Wert gebräuchlich und für das gesamte Verfahren "Regelung mittels Semipulsen".In the known control circuit, the thyristor is driven in such a way that the DC high voltage is applied during a first phase Ti (from, for example, 0.001 to 1 s) and interrupted during a second phase T 2 (from, for example, 0.01 to 1 s) . The expression k-value is used for the ratio of Ti to (T 1 + T 2 ), that is to say from the on-time to the on-time and pause time of each switching cycle, and for the entire method "regulation by means of semipulses".

Das bekannte Verfahren zielt insbesondere darauf ab, einen Gegen-Koronaeffekt zu vermeiden, der im Strom-Spannungskennfeld durch einen vergleichsweise sehr steilen Anstieg des Stroms bei nur geringfügiger Erhöhung der Spannung gekennzeichnet ist. Bei derartigen Kennlinien ist ein hoher Energieaufwand mit niedriger Staubabscheideleistung des Elektrofilters verbunden. Da jedoch das Auftreten des Gegen-Koronaeffektes mit einer gewissen Verzögerung gegenüber einer von der üblichen Regelung veranlaßten Erhöhung der Spannung bzw. des Stroms erfolgt, ist es möglich mit der Methode des Semipulsens die Gegen-Koronaeffekte weitgehend zu vermeiden und einen wirtschaftlichen Betrieb des Elektrofilters zu erreichen.The known method aims in particular to avoid a counter-corona effect, which is characterized in the current-voltage map by a comparatively very steep increase in the current with only a slight increase in the voltage. With such characteristics, high energy consumption is associated with low dust removal performance of the electrostatic filter. However, since the occurrence of the counter-corona effect occurs with a certain delay compared to an increase in the voltage or the current caused by the usual regulation, it is possible with the method of semipulsing to largely avoid the counter-corona effects and to operate the electrostatic filter economically to reach.

Die Maßnahmen gemäß DE-OS 3114 009 zielen also darauf ab, auch im Bereich hoher spezifischer Staubwiderstände eine optimale Abscheideleistung zu erreichen.The measures according to DE-OS 3114 009 are therefore aimed at achieving optimum separation performance even in the area of high specific dust resistances.

Unberücksichtigt bleibt dabei aber, daß mit einer optimalen Abscheideleistung - je nachdem wie hoch der spezifische Staubwiderstand ist - ganz unterschiedliche Reingasstaubgehalte erreicht werden, die von einem vorgeschriebenen Wert nach oben und unten abweichen können. Mit anderen Worten, die bekannte Regelung orientiert sich nicht an dem eigentlichen Ziel der Staubabscheidung, nämlich den ursprünglich vorhandenen Staubgehalt auf einen Wert zu senken, der den Vorschriften entspricht. Eine wesentliche Unterschreitung vorgegebener Reingasstaubgehalte mag im Hinblick auf den Umweltschutz an sich zwar wünschenswert sein, belastet die Produktion aber mit vermeidbaren Kosten und gefährdet zumindest tendenziell die Wettbewerbsfähigkeit. Ohne Einbeziehung des Reingasstaubgehaltes in das Regelsystem für einen Elektrofilter mag die Regelung zwar technisch optimal sein, eine wirtschaftliche Optimierung kann so aber nicht erreicht werden.However, it is not taken into account that with an optimal separation performance - depending on how high the specific dust resistance is - very different clean gas dust contents can be achieved, which can deviate from a prescribed value upwards and downwards. In other words, the known regulation is not based on the actual goal of dust separation, namely to reduce the originally present dust content to a value that complies with the regulations. A significant drop below the specified clean gas dust levels may be desirable in terms of environmental protection as such, but it imposes avoidable costs on production and at least tends to jeopardize competitiveness. Without including the clean gas dust content in the control system for an electrostatic precipitator, the control may be technically optimal, but economic optimization cannot be achieved in this way.

Es besteht somit die Aufgabe, das anhand der DE-OS 31 14 009 skizzerte Regelverfahren für ein Elektrofilter dahingehend weiterzuentwicklen, daß unter wechselnden Betriebsbedingungen nicht nur die jeweils optimale Abscheideleistung erreicht wird, sondern daß der vorgeschriebene Reingasstaub jeweils unter wirtschaftlich optimalen Bedingungen, d.h. mit kleinstmöglichem Energieaufwand eingehalten wird.It is therefore the task of further developing the control method for an electrostatic filter, sketched on the basis of DE-OS 31 14 009, in such a way that not only the optimum separation performance is achieved under changing operating conditions, but that the prescribed clean gas dust is achieved under economically optimal conditions, i.e. is observed with the lowest possible energy consumption.

Zur Lösung dieser Aufgabe wird bei dem gattungsmäßigen Verfahren vorgeschlagen, daß

  • a) für ein vorgegebenes Elektrofilter ein repräsentatives Feld der Strom-Spannungs-Kennlinien für ungepulste Spannung (k = 1) bei verschiedenen Staubwiderständen aufgenommen wird (I = f(V,92»,
  • b) zu jeder Kennlinie derjenige kleinste k-Wert ermittelt wird, mit dem der vorgegebene Reingasstaubgehalt noch erreicht wird,
  • c) jeder Kennlinie der so ermittelte kleinste k-Wert zugeordnet wird und die laufende Regelung des Elektrofilters anhand dieses Kennfeldes vorgenommen wird, indem
  • d) die aktuelle Kennlinie bei ungepulster Spannung mit dem Kennfeld verglichen und schließlich der k-Wert eingestellt wird, der zu der Kennlinie des Feldes gehört, die mit der aktuellen Kennlinie zusammenfällt bzw. als nächste unterhalb der aktuellen Kennlinie liegt.
To solve this problem it is proposed in the generic method that
  • a) for a given electrostatic filter, a representative field of the current-voltage characteristic curves for unpulsed voltage (k = 1) with different dust resistances is recorded (I = f (V, 92 »,
  • b) the smallest k-value is determined for each characteristic with which the specified clean gas dust content is still achieved,
  • c) each characteristic curve is assigned the smallest k value determined in this way and the current control of the electrostatic filter is carried out on the basis of this characteristic map by
  • d) the current characteristic with unpulsed voltage is compared with the characteristic diagram and finally the k-value is set which belongs to the characteristic of the field that coincides with the current characteristic or is next below the current characteristic.

In weiterer Ausbildung des Erfindungsgedankens ist vorgesehen, daß das Kennfeld entweder bei der Inbetriebnahme eines Elektrofilters oder anhand von Erfahrungswerten erstellt wird. Außerdem ist vorgesehen, daß das Kennfeld unter Verwendung der im Betrieb ermittelten aktuellen Kennlinien laufend korrigiert wird. Die Einstellung des k-Wertes gemäß Maßnahme d) in Anspruch 1 wird in vorgegebenen zeitlichen Abständen wiederholt. Schließlich ist bei dem erfindungsgemäßen Verfahren vorgesehen, daß alle Verfahrensschritte völlig automatisch ablaufen.In a further development of the inventive concept, it is provided that the characteristic diagram is created either when an electrostatic filter is started up or on the basis of empirical values. It is also provided that the map is continuously corrected using the current characteristic curves determined during operation. The setting of the k value according to measure d) in claim 1 is repeated at predetermined time intervals. Finally, it is provided in the method according to the invention that all method steps run completely automatically.

Weitere Einzelheiten und Vorteile werden anhand der Figuren 1 bis 5 näher erläutert.

  • Fig. 1 zeigt das vereinfachte Schaltbild für die Spannungsversorgung eines Elektrofilters mit Semipuls-Regelung.
  • Fig. 2 zeigt den zeitlichen Verlauf der Primärspannung bei einem k-Wert = 1/3.
  • Fig. 3 zeigt den zeitlichen Verlauf des Filterstromes bei einem k-Wert = 1/3.
  • Fig. 4 zeigt die am Elektrofilter anliegende Spannung bei einem k-Wert = 1/3.
  • Fig. 5 zeigt vier Strom-Spannungskennlinien, denen vier verschiedene k-Werte zugeordnet sind.
Further details and advantages are explained in more detail with reference to FIGS. 1 to 5.
  • Fig. 1 shows the simplified circuit diagram for the voltage supply of an electrostatic filter with semi-pulse control.
  • 2 shows the time profile of the primary voltage at a k value = 1/3.
  • Fig. 3 shows the time course of the filter current at a k value = 1/3.
  • Fig. 4 shows the voltage applied to the electrostatic filter at a k-value = 1/3.
  • 5 shows four current-voltage characteristics, to which four different k values are assigned.

Die Einspeisung der Energie in das Elektrofilter erfolgt gemäß Fig. 1 über zwei antiparallel geschalteten Thyristo ren 1, einen Hochspannungstransformator 3 und einen Gleichrichter 4. Die Niederschlagselektroden liegen wie das Filtergehäuse 7 an Erde 8, während die Sprühelektroden mit dem Minuspol der Hochspannungsquelle verbunden sind. Der Primärstrom des Hochspannungstransformators 3 wird mittels Stromwandler 2 gemessen. Die Ermittlung des Sekundär- bzw. Filterstroms erfolgt über einen Shunt 5, während die Sekundär- bzw. Filterspannung über eine Meßbrücke 6a, 6b gemessen wird. Die Meßwerte (von 2, 5, 6a und 6b) werden einem elektronischen Regelgerät 9 zugeführt, das die Impulse zum Zünden des Thyristors 1 erzeugt. Das Regelgerät 9 arbeitet vollautomatisch; es überwacht den Strom und verhindert, daß der Nennstrom überschritten wird; es überwacht die Spannung und sorgt dafür, daß immer mit einer möglichst nahe an der Überschlagsspannung liegenden Spannung gearbeitet wird, daß bei Überschlägen die Spannung abgesenkt und bei Dauerkurzschluß die Anlage abgeschaltet wird.The energy is fed into the electrostatic filter according to FIG. 1 via two antiparallel connected Thyristo ren 1, a high voltage transformer 3 and a rectifier 4. The precipitation electrodes are like the filter housing 7 to earth 8, while the spray electrodes are connected to the negative pole of the high voltage source. The primary current of the high-voltage transformer 3 is measured by means of a current transformer 2. The secondary or filter current is determined via a shunt 5, while the secondary or filter voltage is measured via a measuring bridge 6a, 6b. The measured values (from 2, 5, 6a and 6b) are fed to an electronic control device 9, which generates the pulses for firing the thyristor 1. The control device 9 works fully automatically; it monitors the current and prevents the nominal current from being exceeded; it monitors the voltage and ensures that the voltage used is as close as possible to the breakdown voltage, that the voltage is reduced in the event of flashovers and that the system is switched off in the event of a permanent short circuit.

Außerdem ist ein Mikrocomputer 10 vorgesehen, in dem die digitalisierten Kennlinien des Filters mit den zugehörigen k-Werten abgespeichert sind. In vorgegebenen Intervallen wird über das Regelgerät 9 die aktuelle Strom-Spannungskennlinie des Filters aufgenommen, diese mit den gespeicherten Kennlinien verglichen und ein neuer k-Wert an das Regelgerät weitergegeben, falls sich aus dem Kennlinienvergleich ein günstigerer k-Wert ergeben hat.In addition, a microcomputer 10 is provided in which the digitized characteristics of the filter with the associated k values are stored. At predetermined intervals, the current current-voltage characteristic curve of the filter is recorded via the control device 9, compared with the stored characteristic curves and a new k value passed on to the control device if a more favorable k value has resulted from the comparison of the characteristic curves.

Erfindungsgemäß sind den unter verschiedenen Betriebsbedingungen aufgenommenen Kennlinien jeweils die k-Werte zugeordnet, mit denen ein vorgegebener Reingasstaubgehalt mit geringstmöglichem Energieaufwand eingehalten werden kann. Da die Meß- und Rechenvorgänge sehr schnell ablaufen, tritt während der Neuaufnahme einer Kennlinie keine Verschlechterung des Abscheidegrades auf. Da moderne Elektrofilter zudem in der Regel mehrere hintereinander geschaltete Filter aufweisen, die in der beschriebenen Weise nacheinander überprüft und optimiert werden, können selbst stark und rasch wechselnde Änderungen der Betriebszustände unter Beibehaltung der Energieverbrauchsoptimierung ohne Überschreitung vorgegebener Reingasstaubgehalte ausgeregelt werden.According to the invention, the characteristic values recorded under different operating conditions are each assigned the k values with which a predetermined clean gas dust content can be maintained with the least possible energy expenditure. Since the measurement and calculation processes run very quickly, there is no deterioration in the degree of separation during the recording of a new characteristic. Since modern electrostatic precipitators generally also have several filters connected in series, which are checked and optimized in succession in the manner described, even strongly and rapidly changing changes in the operating states can be compensated for while maintaining the energy consumption optimization without exceeding the predetermined clean gas dust contents.

Außerdem ist es möglich, jeweils nur ausgewählte Teilstücke der Kennlinien miteinander zu vergleichen, wobei die Zeit für die Aufnahme des Kennlinienteils entsprechend verkürzt und dementsprechend auch schneller auf Änderungen im Filterbetrieb reagiert werden kann. Die Wiederholungsintervalle können zwischen wenigen Minuten und Stunden eingestellt werden, je nach dem ob es sich wie bei der Entstaubung von Stahlkonvertern um rasch wechselnde Betriebszustände oder um nur geringfügige und langsame Änderungen wie bei der Entstaubung der Kesselabgase von Kraftwerken handelt.In addition, it is possible to compare only selected sections of the characteristic curves with one another, the time for recording the characteristic curve part being shortened accordingly and, accordingly, also being able to react more quickly to changes in filter operation. The repetition intervals can be set between a few minutes and hours, depending on whether, like the dedusting of steel converters, there are rapidly changing operating states or only minor and slow changes, such as the dedusting of the boiler exhaust gases from power plants.

In Fig. 2 ist die Primärspannung des Hochspannungstransformators 3 als gestrichelte Linie für den Wert k=1 (umgepulst) und als durchgezogene Linie für den Wert k=1/3 dargestellt, d.h. es wird von insgesamt 3 vollen Sinuswellen über den Thyristor nur jede dritte gezündet.In Fig. 2 the primary voltage of the high voltage transformer 3 is shown as a broken line for the value k = 1 (wrapped) and as a solid line for the value k = 1/3, i.e. of a total of 3 full sine waves, only every third is fired via the thyristor.

In Fig. 3 ist der Sekundärstrom des Gleichrichters 4 bzw. der Flterstrom bei einem Pulsbetrieb gemäß Fig. 1 dargestellt. Auf jeweils zwei Pulse folgt eine stromlose Zeit von doppelter Länge der Pulszeit.FIG. 3 shows the secondary current of the rectifier 4 or the filter current during a pulse operation according to FIG. 1. Every two pulses are followed by an unpowered time of twice the pulse time.

Fig. 4 zeigt die am Elektrofilter anliegende Spannung. Da das Filter als Kondensator wirkt, geht die Spannung nach dem Pulsen nicht auf Null zurück, sondern auf einen mehr oder weniger hohen "Restwert". Bei erneutem Pulsen wird sie wieder auf den maximalen Wert angehoben.Fig. 4 shows the voltage applied to the electrostatic filter. Since the filter acts as a capacitor, the voltage does not go back to zero after pulsing, but to a more or less high "residual value". When pulsing again, it is raised again to the maximum value.

Fig. 5 schließlich zeigt das Kennlinienfeld eines Filters, d.h. den aufgenommenen Strom als Funktion der angelegten Spannung für verschiedene Betriebszustände. Letztere werden durch die Gastempertur, die Gaszusammensetzung, den Staubwiderstand und durch eine Reihe weiterer Einflußgrößen bestimmt. Erfindungsgemäß sind den verschiedenen Kennlinien die k-Werte zugeordnet worden, die angewandt werden müssen, wenn der vorgegebene Reingasstaubgehalt mit kleinstmöglichem Energieaufwand erreicht werden soll.Finally, Fig. 5 shows the characteristic field of a filter, i.e. the current consumed as a function of the applied voltage for various operating states. The latter are determined by the gas temperature, the gas composition, the dust resistance and by a number of other influencing factors. According to the invention, the various characteristic curves have been assigned the k-values which have to be used if the specified clean gas dust content is to be achieved with the least possible energy expenditure.

Die mit k=1 bezeichnete Kennlinie zeigt den für niedrige Staubwiderstände bis etwa 1011 Q cm typischen Verlauf, während die mit k = 0,1 bezeichnete Kennlinie den Verlauf bei sehr hohen Staubwiderstand mit mehr als 1013 0 cm zeigt. Die beiden anderen Kennlinien beziehen sich auf dazwischen liegende Staubwiderstände.The characteristic curve labeled k = 1 shows the curve typical for low dust resistances up to about 10 11 Q cm, while the curve labeled k = 0.1 shows the curve for very high dust resistance with more than 10 13 0 cm. The other two characteristics relate to dust resistance in between.

Aus der Zuordnung der k-Werte zu den Kennlinien läßt sich folgendes ablesen. Während man bei niedrigen Staubwiderständen den vorgegebenen Reingasstaubgehalt am besten mit einer ungepulsten Arbeitsweise erreicht, wird das gleiche Ziel bei sehr hohen Staubwiderständen erreicht, wenn die Pausenzeit beispielsweise 9 mal so lang ist, wie die Pulszeit Ti, d.h. wenn nur während einem 1/10 der Zeit gepulst wird. Interessant und optimierungsbedürftig sind insbesondere die Kennlinien zwischen den k-Werten 1 und 0,1, weil der Staubwiderstand in vielen Fällen zwischen 1011 und 1013 Q cm liegt und hier eine wiederholte, genaue Anpassung an die aktuellen Gegebenheiten besonders wichtig und lohnend ist.The following can be seen from the assignment of the k values to the characteristic curves. While the specified clean gas dust content is best achieved with a low-pulsation method at low dust resistances, the same goal is achieved with very high dust resistances if the pause time is, for example, 9 times as long as the pulse time T i , i.e. if only during a 1/10 the time is pulsed. The characteristic curves between the k values 1 and 0.1 are particularly interesting and need to be optimized because the dust resistance is in many cases between 1011 and 10 13 Q cm and a repeated, precise adjustment to the current conditions is particularly important and worthwhile.

Mit dem erfindungsgemäßen Verfahren ist es möglich, unter allen vorkommenden Betriebszuständen einen vorgegebenen Reingasstaubgehalt mit geringstem Energieaufwand zu erreichen. Bei der Festlegung von Emissionsgrenzen kann man nicht nur eine möglichst geringe Umweltbelastung anstreben, man muß auch die technischen Möglichkeiten und wirtschaftlichen Belastungen berücksichtigen. Würden die Reingasstaubgehalte beispielsweise bei einer Stromerzeugungsanlage so niedrig angesetzt, daß der Aufwand sie zu realisieren, so hoch ist, daß mit dem erzeugten Strom keine Gewinne gemacht werden können, dann würde man solche Anlage nicht mehr betreiben bzw. gar nicht erst bauen. Will man aber die Stromversorgung sicherstellen, dann müssen die Reingasstaubgehalte realistisch festgelegt werden. Wenn nun unter Verwendung des Erfindungsgedankens nicht ein kleinstmöglicher Reingasstaubgehalt - ohne Rücksicht auf den Energieaufwand - sondern die Einhaltung eines vorgegebenen Reingasstaubgehaltes mit gerinstmöglichem Energieaufwand angestrebt und realisiert wird, so kann das dazu führen, daß auch niedrigere Reingasstaubgehalte realistisch, d.h. technisch und wirtschaftlich realisierbar werden.With the method according to the invention, it is possible to achieve a predetermined clean gas dust content with the least energy expenditure under all occurring operating conditions. When setting emission limits, one can not only strive for the lowest possible environmental impact, one must also take into account the technical possibilities and economic impact. If the clean gas dust contents were set so low, for example in a power generation plant, that the effort to implement them is so high that no profits can be made with the electricity generated, then such a plant would no longer be operated or would not be built at all. But if you want to ensure the power supply, then the clean gas dust content must be set realistically. If, using the concept of the invention, not the smallest possible clean gas dust content - regardless of the energy effort - but the adherence to a specified clean gas dust content with the lowest possible energy expenditure is sought and realized, this can lead to the fact that even lower clean gas dust contents are realistic, ie technically and economically feasible.

Claims (6)

1. An automatic control method for an electrostatic precipitator which is supplied with energy from an alternating current grid by thyristors, a high-voltage transformer and a rectifier, and in which the power control takes place by intermittent triggering of the thyristors in such a way that during a first phase T1 the direct current high voltage is applied between the electrodes and that it is interrupted during a second phase T2, the repetition period and the pulse width being adjustable, characterised in that the expenditure of energy at a predetermined pure gas dust content is minimised by
a) representative current-voltage characteristics for unpulsed voltage (k = 1) being recorded at different dust resistivities (I = f(V, Q)),
b) for each characteristic the lowest k-value being determined with which the predetermined pure gas dust content is still achieved,
c) the lowest k-value thus determined being associated with each characteristic, and the continuous automatic control of the electrostatic precipitator being performed with reference to these recorded characteristics by
d) comparing the actual characteristic at unpulsed voltage with the recorded characteristics and finally setting the k-value which belongs to the recorded characteristic which coincides with the actual characteristic or is next below the actual characteristic for a given electrostatic precipitator.
2. A method according to Claim 1, characterised in that the characteristics are recorded when an electrostatic precipitator is put into operation.
3. A method according to Claim 1, characterised in that the characteristics are drawn up with experimental values.
4. A method according to one of Claims 1 to 3, characterised in that the recorded characteristics are continually corrected using the actual characteristics determined during operation.
5. A method according to one of Claims 1 to 4, characterised in that the setting of the k-value in accordance with measure d) in Claim 1 is repeated at predetermined intervals in time.
6. A method according to one of Claims 1 to 5, characterised in that the sequence of individual steps takes place fully automatically.
EP86201035A 1985-07-26 1986-06-14 Control method for an electrostatic filter Expired EP0210675B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86201035T ATE46630T1 (en) 1985-07-26 1986-06-14 CONTROL METHOD FOR AN ELECTRIC FILTER.

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DE19853526754 DE3526754A1 (en) 1985-07-26 1985-07-26 CONTROL METHOD FOR AN ELECTRIC FILTER
DE3526754 1985-07-26

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EP0210675A1 EP0210675A1 (en) 1987-02-04
EP0210675B1 true EP0210675B1 (en) 1989-09-27

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JP (1) JPS6336856A (en)
KR (1) KR930009721B1 (en)
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DE (2) DE3526754A1 (en)
ES (1) ES2000746A6 (en)
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CN105992651A (en) * 2013-11-13 2016-10-05 首要金属科技奥地利有限责任公司 Filtering of an exhaust gas of a metallurgical plant, which exhaust gas comprises solid particles

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DK552186A (en) * 1986-11-19 1988-05-20 Smidth & Co As F L METHOD AND APPARATUS FOR DETECTING RETURN RADIATION IN AN ELECTROFILTER WITH GENERAL OR INTERMITTING POWER SUPPLY
DE3910123C1 (en) * 1989-03-29 1990-05-23 Walther & Cie Ag, 5000 Koeln, De Method for optimising the energy consumption when operating an electrostatic precipitator
DE10050188C1 (en) * 2000-10-09 2002-01-24 Siemens Ag Electrofilter operating method uses filter model divided into zones assigned characteristic values used for regulating energy feed for ensuring operation within particle emission limits
CH713394A1 (en) * 2017-01-30 2018-07-31 Clean Air Entpr Ag Electrostatic precipitator.
CN114100860B (en) * 2022-01-29 2022-04-19 华能平凉发电有限责任公司 Flashover voltage control method and device for electric dust collector

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DE2540084C2 (en) * 1975-09-09 1983-08-25 Metallgesellschaft Ag, 6000 Frankfurt Device for detecting flashovers on the high voltage side in an electrostatic precipitator
CA1089002A (en) * 1976-08-13 1980-11-04 Richard K. Davis Automatic control system for electric precipitators
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Publication number Priority date Publication date Assignee Title
CN105992651A (en) * 2013-11-13 2016-10-05 首要金属科技奥地利有限责任公司 Filtering of an exhaust gas of a metallurgical plant, which exhaust gas comprises solid particles

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IN168831B (en) 1991-06-22
DE3665820D1 (en) 1989-11-02
ZA865571B (en) 1988-03-30
DE3526754A1 (en) 1987-01-29
EP0210675A1 (en) 1987-02-04
CA1271516A (en) 1990-07-10
ATE46630T1 (en) 1989-10-15
US4680036A (en) 1987-07-14
KR930009721B1 (en) 1993-10-09
KR870000967A (en) 1987-03-10
ES2000746A6 (en) 1988-03-16
AU6056286A (en) 1987-01-29
AU580503B2 (en) 1989-01-12
JPS6336856A (en) 1988-02-17

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