EP0734773B1 - Méthode pour l'optimisation continu du régime de travail d'un électrofiltre - Google Patents

Méthode pour l'optimisation continu du régime de travail d'un électrofiltre Download PDF

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Publication number
EP0734773B1
EP0734773B1 EP96103433A EP96103433A EP0734773B1 EP 0734773 B1 EP0734773 B1 EP 0734773B1 EP 96103433 A EP96103433 A EP 96103433A EP 96103433 A EP96103433 A EP 96103433A EP 0734773 B1 EP0734773 B1 EP 0734773B1
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EP
European Patent Office
Prior art keywords
phase
voltage
test phase
period
normal phase
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP96103433A
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German (de)
English (en)
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EP0734773A3 (fr
EP0734773A2 (fr
Inventor
Achim Dr. Deiwick
Frank Bock
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Babcock Prozessautomation GmbH
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Babcock Prozessautomation GmbH
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Application filed by Babcock Prozessautomation GmbH filed Critical Babcock Prozessautomation GmbH
Priority to SI9630411T priority Critical patent/SI0734773T1/xx
Publication of EP0734773A2 publication Critical patent/EP0734773A2/fr
Publication of EP0734773A3 publication Critical patent/EP0734773A3/fr
Application granted granted Critical
Publication of EP0734773B1 publication Critical patent/EP0734773B1/fr
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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

  • An electrostatic precipitator has two sets of electrodes: precipitation electrodes and spray electrodes.
  • the precipitation electrodes usually exist from profiled sheet metal strips that lead to several parallel walls are composed. Two adjacent walls form an alley for the gas stream to be cleaned. They are in the middle of the alley Spray electrodes arranged. They often consist of wires or Ribbons with laces. Usually they are Precipitation electrodes are grounded, and the spray electrodes are with a High voltage source connected.
  • the dust particles to be separated are separated by electrons the spray electrodes are released, ionized and in the between Spray electrodes and precipitation electrodes existing electrostatic field deflected from the gas flow and to the Precipitation electrodes deposited.
  • the carried electrical transfer charge to the precipitation electrode.
  • the dust particles to be separated have a very high specific resistance (> 10 11 ⁇ cm)
  • the electrical charge from the dust layer deposited on the precipitation electrodes cannot flow away as quickly as it is charged by the influx of further charged particles .
  • the result is the so-called back spraying, ie a discharge which is opposite to the discharge occurring at the spray electrodes.
  • the back spraying throws dust back into the gas stream. The degree of separation deteriorates.
  • the electrostatic separation of high-resistance dusts is one certain strength of the current flowing between the electrodes of a Electrofilter flows, optimally.
  • the deposition deteriorates Increase in the current, this is an indication that the Back spraying has started.
  • the optimal operating point depends on the parameters of the cleaning gas flow. If the parameters change, then in a change in the operating point is also generally required. This be explained using a few simple examples:
  • An electrostatic filter can remove the fly ash from the flue gas separate the coal-fired boiler.
  • a generator can be used to generate electrical energy via a turbine operate. The need for electrical energy increases within of the daily load cycle, less steam is required. For Reduced steam generation, less coal is fired. Accordingly, the amount of fly ash that the e-filter decreases must cut off. By changing the mode of operation of the boiler from Full load to partial load thus changes an essential parameter, namely the volume flow of the fly ash.
  • Soot bubbles Water vapor emitted. This process is called Soot bubbles. Soot blowing can be done 3 to 4 times a day and take half an hour to an hour each. The Steam leaves the boiler with the flue gas through the Dust collector. Part of the moisture is deposited on the fly ash particles and changes the electrical properties of fly ash and Flue gas. Soot blowing also changes the operation of the Electro filter essential parameters.
  • Load changes and soot bladders are only examples of perfectly ordinary ones Operations in the operation of an electrostatic filter, in which the Change the parameters of the gas flow to be cleaned.
  • EP 0 097 161 B1 discloses an electrostatic Operate separator with a current that is just the point of insertion of spraying back. Current and voltage are monitored in which one increases or decreases the arousal to the point determine at which the back spraying begins.
  • the stream consists of one Pulse train, and the voltage is a DC voltage with superimposed AC component. With conventional two-way rectification the mains voltage results for the current and the AC component of the voltage a frequency of 100 Hz.
  • EP 0 140 855 B1 describes a method for changing one of the Electrodes of an electrostatic dust collector Known voltage, in which the voltage by one of the Grid frequency derived pulse train is generated and the change by causing the length of the interval between two successive individual pulses by hiding a straight one Number of pulses is varied. The number of pulses per second is depending on the number of hidden pulses, this means that the number is 33, 20, 14, 11, etc. degraded.
  • the mains voltage is one via thyristors High voltage transformer supplied, the secondary side with a Two-way rectifier is connected. The output voltage of the The rectifier is connected to the electrodes of the electrostatic filter.
  • the thyristors are controlled by a control loop that is switched so that it between two pulses that are fed to the electrostatic filter, one Deletes even number of pulses from the mains voltage.
  • the invention has for its object a method for operating an electrostatic precipitator at which the set operating point is continuously monitored and tracked so that the filter is constantly in works close to the optimal operating point. This task will solved according to the invention by the features specified in claim 1.
  • Figure 1 illustrates the course of current and voltage for different cases, characterized by different length of the interval distinguish between two successive pulses.
  • FIG. 1 illustrates the succession of operating periods.
  • Figure 3 illustrates the sequence of cycles within a single one Phase.
  • FIG. 2 shows several successive operating periods m, m + 1, m + 2, ... shown schematically.
  • Each operating period includes one Normal phase and a subsequent test phase.
  • the normal phase takes much longer than the test phase.
  • the duration of the normal phase is preferably about 4: 1 to 20: 1 for the duration of the test phase.
  • the normal phase lasts e.g. B. 1 h, the test phase 5 - 10 min.
  • a constant pulse number is used in each normal phase, also in every test phase. However, the pulse number deviates from the test phase the pulse number of the immediately preceding normal phase by ⁇ 1 as explained below.
  • the normal phase and the test phase each comprise a sequence of cycles, which are consecutively numbered 1, 2, 3, ..., k, k + 1, ...
  • the cycles follow one another at intervals of 20-40 s, preferably approximately 30 s.
  • the associated residual voltage is measured and due to of the measured value obtained becomes the current limit for the following Cycle set, as explained below with reference to Figure 3.
  • the time 0 in FIG. 3 can be any time during the Operation, z. B. the switch-on time or the start of a Normal phase.
  • the current limit for the Cycle k set to 450 mA.
  • the associated residual voltage is according to the upper diagram of Figure 3 at about 25 kV.
  • the current limit is increased to 500 mA to try out whether a higher residual voltage now arises.
  • the increased Current limitation results in a residual voltage of in cycle k + 1 25.8 kV.
  • As the increase in the current limit leads to an increase in the Residual voltage has led to k + in the following cycle Current limit increased again, this time to 550 mA. It follows again an increased residual voltage, namely 26.2 kV.
  • test phase follows the normal phase. In the test phase should be tried out whether with a changed pulse number Deposition can be improved.
  • a pulse number is used that differs from the Pulse number of the immediately preceding normal phase by ⁇ 1 differs. Also in the test phase are analogous to the normal phase go through numerous cycles. After becoming a quasi stationary State has been set, an average of the Voltage calculated and saved. This mean is compared with the Average of the associated normal phase compared.

Claims (6)

  1. Procédé d'optimisation avancée de l'état de fonctionnement d'un électrofiltre avec les caractéristiques suivantes:
    a) on utilise une tension continue dérivée de la tension réseau par un redressement pleine onde avec impulsions superposées, l'écart temporel entre impulsions successives pouvant être modifié par masquage d'un nombre sélectionnable d'ondes réseau entières;
    b) des périodes d'exploitation successives (1, 2, 3, ..., m, ...) comprennent chacune une phase normale et une phase de test subséquente;
    c) Lors de chaque période d'exploitation, on travaille avec un nombre d'impulsions constant dans la phase normale et dans la phase de test;
    d) pendant la phase normale et la phase de test, on mesure chaque fois la tension résiduelle au cours de cycles successifs (1, 2, 3, ..., k, ...) pour une limitation donnée du courant ou de la tension et la limitation est modifiée de manière itérative de cycle en cycle en fonction de la modification de la tension résiduelle, de façon à rechercher un maximum de la tension résiduelle;
    e) lors de chaque période d'exploitation (1, 2, 3, ..., m, ...), on travaille dans la phase de test avec un nombre d'impulsions modifié de ± 1 en comparaison avec la phase normale et les valeurs moyennes de la tension dans la phase normale et dans la phase de test sont mesurées et comparées entre elles, et, en fonction de la différence, le nombre d'impulsions est modifié de manière itérative de période d'exploitation en période d'exploitation, de sorte que la valeur moyenne de la tension s'approche d'un maximum.
  2. Procédé suivant la revendication 1 d'optimisation continue de l'état de fonctionnement d'un électrofiltre avec les caractéristiques suivantes:
    a) on utilise une tension continue dérivée de la tension réseau par un redressement pleine onde avec impulsions superposées, l'écart temporel entre impulsions successives pouvant être modifié par masquage d'un nombre sélectionnable d'ondes réseau entières;
    b) des périodes d'exploitation successives (1, 2, 3, ..., m, ...) comprennent chacune une phase normale et une phase de test subséquente;
    c) lors de chaque période d'exploitation, on travaille avec un nombre d'impulsions constant dans la phase normale et dans la phase de test;
    d) le nombre d'impulsions de la phase de test diffère de ± 1 du nombre d'impulsions de la phase normale immédiatement précédente, le signe étant déterminé suivant les caractéristiques subséquentes h et i :
    e) la phase normale et la phase de test comprennent chacune une suite de cycles (1, 2, 3, ..., k, ...) selon le schéma suivant:
    ea) le courant est limité à ik;
    eb) la tension résiduelle uk est mesurée;
    ec) le courant est limité à une valeur ik+1 = ik + Δik différant de ik, Δik étant positif ou négatif et la valeur absolue | Δik | étant petite par rapport à ik;
    ed) la tension résiduelle uk+i est mesurée;
    ee) la différence Δuk = uk+1 - uk est déterminée;
    ef) le courant est limité à une valeur ik+2 = ik+1 ± Δik différant de ik+1, le signe correspondant au signe de Δik suivant ec) si et seulement si le signe de Δuk suivant ee) est positif;
    f) tant dans la phase normale que dans la phase de test, on détermine et enregistre au moins dans la période finale une valeur moyenne de la tension;
    g) la valeur moyenne de la phase de test est comparée à la valeur moyenne de la phase normale correspondante.
    h) si au cours de la période (m) la valeur moyenne de la phase de test n'est pas supérieure à celle de la phase normale, on travaille au cours de la phase normale de la période suivante (m + 1) avec le même nombre d'impulsions que dans la phase normale de la période (m) et lors du passage à la phase de test le nombre d'impulsions est modifié en sens inverse de celui de la période (m);
    i) si cependant au cours de la période (m) la valeur moyenne de la phase de test est supérieure à celle de la phase normale, on travaille au cours de la phase normale de la période suivante (m + 1) avec le même nombre d'impulsions que dans la phase de test de la période (m) et lors du passage à la phase de test le nombre d'impulsions est modifié dans le même sens que celui de la période (m) ;
  3. Procédé suivant la revendication 1 ou 2, caractérisé en ce que la durée de la phase normale est à celle de la phase de test dans un rapport de 4:1 à 20:1.
  4. Procédé suivant l'une des revendications 1 à 3, caractérisé en ce que la durée d'une période d'exploitation est de 1 à 2 h.
  5. Procédé suivant l'une des revendications 1 à 4, caractérisé en ce que la durée d'un cycle est de 10 à 30 s.
  6. Procédé suivant l'une des revendications 2 à 5, caractérisé en ce que la valeur absolue | Δik | est comprise entre 0,05 ik et 0,15 ik.
EP96103433A 1995-03-30 1996-03-06 Méthode pour l'optimisation continu du régime de travail d'un électrofiltre Expired - Lifetime EP0734773B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
SI9630411T SI0734773T1 (en) 1995-03-30 1996-03-06 Method for continuous optimization of the operating condition of an electrofilter

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19511604A DE19511604C2 (de) 1995-03-30 1995-03-30 Verfahren zum fortgesetzten Optimieren des Betriebszustandes eines Elektrofilters
DE19511604 1995-03-30

Publications (3)

Publication Number Publication Date
EP0734773A2 EP0734773A2 (fr) 1996-10-02
EP0734773A3 EP0734773A3 (fr) 2000-02-02
EP0734773B1 true EP0734773B1 (fr) 2001-10-24

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EP96103433A Expired - Lifetime EP0734773B1 (fr) 1995-03-30 1996-03-06 Méthode pour l'optimisation continu du régime de travail d'un électrofiltre

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EP (1) EP0734773B1 (fr)
AT (1) ATE207388T1 (fr)
DE (2) DE19511604C2 (fr)
SI (1) SI0734773T1 (fr)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108380391B (zh) * 2018-02-11 2024-01-30 洁通科技（北京）有限公司 无臭氧双路四电压高压静电除尘器及其控制方法

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2949786A1 (de) * 1979-12-11 1981-06-19 Siemens AG, 1000 Berlin und 8000 München Verfahren zum ermitteln der filterstromgrenze eines elektrofilters
DE3275706D1 (en) * 1981-07-24 1987-04-23 Rodney John Truce Detecting, measuring and applying back corona parameters on an electrostatic precipitator
SE451675B (sv) * 1983-10-05 1987-10-26 Flaekt Ab Sett och anordning for att variera en mellan elektrostatiska stoftavskiljares elektroder upptredande spenning
JPS6125650A (ja) * 1984-07-17 1986-02-04 Sumitomo Heavy Ind Ltd 電気集塵装置の荷電制御方法
GB8431294D0 (en) * 1984-12-12 1985-01-23 Smidth & Co As F L Controlling intermittant voltage supply
DE3526009A1 (de) * 1985-07-20 1987-01-22 Metallgesellschaft Ag Regelverfahren fuer ein elektrofilter
SE463353B (sv) * 1989-03-28 1990-11-12 Flaekt Ab Saett att reglera stroempulsmatning till en elektrostatisk stoftavskiljare
US5311420A (en) * 1992-07-17 1994-05-10 Environmental Elements Corp. Automatic back corona detection and protection system

Also Published As

Publication number Publication date
DE19511604C2 (de) 1999-08-12
DE59607969D1 (de) 2001-11-29
SI0734773T1 (en) 2002-06-30
DE19511604A1 (de) 1996-10-02
EP0734773A3 (fr) 2000-02-02
EP0734773A2 (fr) 1996-10-02
ATE207388T1 (de) 2001-11-15

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