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Keywords:

  • atmospheric emissions;
  • flue gas;
  • fly ash

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODOLOGY
  5. PLANNING OF THE TESTS
  6. RESULTS
  7. CONCLUSIONS
  8. ACKNOWLEDGMENT
  9. LITERATURE CITED

This article describes a number of tests that have been carried out using a pilot electrostatic precipitator (ESP) which operates with flue gases from a coal power plant. The purpose of these tests was to show the influence of the characteristics of the ash (resistivity) and the main design variables of an ESP (type of discharge electrode and collecting plate spacing) on the fouling of plates and discharge electrodes and the reentrainment of dust. Two types of coal, with high and low resistivity ashes, respectively, three types of discharge electrodes, and three typical collecting plate spacings were used in the tests. In fouling tests, the dust emission growth rate during periods with no rapping, the maximum permissible rapping interval, and the recuperation rate of the dust emission level after rapping were characterized. The maximum permissible rapping interval was defined as the time in which no alteration is observed in the operational variables of the ESP. In rapping tests, the relative increase of the dust emission level due to reentrainment was also characterized. The results of these tests have made possible to identify, for each of the tested coals, the ESP configurations (plate spacing and type of electrode) less sensitive to the formation of a permanent layer of ash and to the particle reentrainment due to rapping. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 7–14, 2015


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODOLOGY
  5. PLANNING OF THE TESTS
  6. RESULTS
  7. CONCLUSIONS
  8. ACKNOWLEDGMENT
  9. LITERATURE CITED

During the ESPs' performance, electrostatically fixed ash layers are removed from both collecting plates and discharge electrodes by rapping. Rapping is normally carried out by means of rotating hammers activated at specific intervals. The fouling of collecting and discharge electrodes and the particle reentrainment due to rapping usually place serious limitations on the efficiency of ESPs operating with coal ash. In this sense, the correct timing and intensity of rapping is especially important for a proper elimination of the ash layers and thus avoiding the deterioration of the ESPs operation [1, 2].

The degree of fouling of the electrodes and the reentrainment level due to rapping mainly depend on the design characteristics of the equipment (geometry of the ESP and electrical operating variables) and the characteristics of the ash, particularly resistivity [3]. Excessive fouling of high resistivity ash over collecting and discharge electrodes causes an increase of the electric field strength into the dust layer and drives to an increase in dust emission as a consequence of back corona problems [4-6]. Low resistivity in the collected ash layer produces an increase in dust emissions due to the reentrainment of captured particles during rapping, especially in the final sections of the unit [4-6].

Different solutions have been proposed for reduction of rapping reentrainment and fouling of the electrodes [7-10]. However, only some fundamental works have been done on the mechanic for removing the electrostatically fixed ash layers from the electrodes [11, 12]. These studies, carried out at laboratory scale, are not very useful to reach conclusions about design and operation of industrial ESPs. Another experimental work at pilot scale regarding the study and the minimization of the effect of rapping and fouling of ESPs only consider the influence of the rapping system on the reentrainment [13]. Nevertheless, ash properties and design parameters as type of discharge electrode, plate spacing, and energization mode play a very important contribution to rapping reentrainment and fouling [14]. On other hand, theoretical and laboratory studies have been carried out to determine the influence of the ash properties and geometric configuration on the global ESP performance [15, 16]. The specific influence of these parameters on the fouling and reentrainment effect has been little studied [9].

With the aim to characterize the influence of the main design parameters of ESPs on fouling and reentrainment due to rapping in an ESP, a number of experiments have been carried out in a pilot electrostatic precipitator (PESP). The PESP treats flue gases from the operation in a 550 MWe power plant (Los Barrios, Spain). In the test, the effect of the use of different PESP configurations, discharge electrodes, and collecting plate spacing, on fouling and reentrainment was evaluated for two types of coal with high and low resistivity ashes, respectively.

METHODOLOGY

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODOLOGY
  5. PLANNING OF THE TESTS
  6. RESULTS
  7. CONCLUSIONS
  8. ACKNOWLEDGMENT
  9. LITERATURE CITED

The tests were carried out by operating the PESP with a flue gas stream isokinetically extracted from the main flow of intake gases to the ESP in a Spanish coal power plant. The PESP is capable of treating up to 20,000 m3/h of flue gas, equivalent to 12 MWt in the boiler [17]. Its configuration is very versatile. It is possible to alter the plate spacing, the type of discharge electrode, the energization mode, the flow rate, and the rapping variables. The PESP consists of three independent electrical sections in series. Each plate courtain and each discharge electrode frame is rapped independently with oscillating hammers. The main characteristics of this pilot unit are shown in Table 1 and in Figures 1 and 2.

Table 1. Characteristics of the pilot ESP.
 
Precipitation chamber dimensions
Length (m)12.6
Width (m)2.5
Height (m)2.6
Number of electrical sections3
Configuration of electrical sections
Effective length (m)2
Effective height (m)2.2
Number of gas passages3–7
Plate spacing (mm)200–500
Number of electrodes per passage4–12
Operating conditions
Gas flow (m3/h)9,000–20,000
Precipitation area (m2)79.2–184.8
SCA (m2/m3s)14–74
Gas velocity (m/s)0.8–1.8
Transformers-rectifiers
Peak voltage (kV)120
Average maximum voltage (kV)78
Maximum effective current (mA)42
image

Figure 1. ESP pilot plant layout.

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image

Figure 2. Pilot electrostatic precipitator. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

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The pilot plant is equipped with a complete automatic control and monitoring system, as shown in Figure 3. This system controls the gas flow and the chamber pressure by using two fans located upstream and downstream of the PESP, respectively. Gas temperature is controlled by a heating element located in the gas intake. The gas flow is continuously measured by a venturi. The emission of dust is monitored by using the extinction signal (attenuation of a light beam traversing a medium through absorption and scattering translated into an electrical signal) from a MIP-Oy opacimeter model LM3188. Also, to correlate the extinction signal from the opacimeter and the dust emission value, gas samples were taken using EPA method 17A during the tests.

image

Figure 3. Pilot ESP instrumentation and control diagram.

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In addition, continuous monitoring was carried out for every electrical parameter characteristic of each section of the PESP: voltage, current, and sparking level. It is possible to use different energization systems: continuous, intermittent, voltage limited, or current limited. To maintain similar electrical conditions in all of the tests, the PESP was operated with continuous energization controlled by voltage maximization and arc or sparking level limiting.

PLANNING OF THE TESTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODOLOGY
  5. PLANNING OF THE TESTS
  6. RESULTS
  7. CONCLUSIONS
  8. ACKNOWLEDGMENT
  9. LITERATURE CITED

Two types of tests were carried out: rapping tests and fouling tests.

In the rapping tests, dust emission was characterized without rapping, emissions base level (EBL), and during rapping (ER). As a result of this test, the relative increase in emission (ΔE) was calculated as: ΔE=100(ER − EBL)/EBL.

The fouling tests consisted of the monitoring of the PESP operational parameters during a long period of operation with no rapping. Deterioration levels were determined for the variables affected by the deposit of the layer of stable dust on the plates and discharge electrodes. After the period with no rapping, exhaustive cleaning was carried out by continuous rapping of the plates and discharge electrodes frames for 10–15 min. Dust emission was characterized at the beginning of the test, before, and after rapping. Rapping was activated when one of the following limits was exceeded:

  • Emission: Ext = 1.05 × Extinitial
  • Average operating voltage: V = 1.15 × Vinitial
  • Average operating current: I = 0.70 × Iinitial
  • Sparking: S = 40 spark/min
  • Appearance of signs of back corona, if they did not exist at the beginning of the test.

The period with no rapping is called maximum characteristic time (maximum period of time for intervals between rapping operation without a significant deterioration in the ESP operation).

To guarantee the same baseline conditions, all the tests were carried out by maintaining the same gas flow rate velocity through the PESP, same temperature, and approximately the same intake dust load. Also, the tests were carried out within the same timeframes, so that possible interferences due to operations in the boiler could be the same in all cases.

Different PESP configurations were tested as the result of the combination of two types of coal, three types of electrodes, and three different plate spacings.

Coals' properties are shown in Table 2. These are good quality internationally traded coals, with low ash content, which generate ash layers with different physical and chemical properties. This means that the electrical and cohesive behavior in the electrostatic precipitation process is very different. Resistivity values were determined in situ, in the gas intake duct of the plant, with a Whalco Resistivity Probe.

Table 2. Characteristics of the types of coal used.
Ultimate analysis (% w/w d.b.)South African coalColombian coal
C74.379.0
H4.15.2
N1.81.5
O6.47.3
S0.70.8
Ash12.76.2
Humidity8.08.0
Higher heating value (gross, d.b.) (kcal/kg)6,8007,600
Fly ash resistivity (Ω cm)1012−1013108−109
Inlet PESP particulate concentration (mg/Nm3)6,500–8,5004,000–5,000

The types of discharge electrodes selected are those with the most widely different electrical characteristics (Figure 4):

  • Barb electrode, a high power electrode, supplying high voltages and currents.
  • Pipe and spike electrode, medium power, supplying high voltage levels with intermediate currents.
  • Twisted rod electrode, low power, supplying very high voltages and low currents.
image

Figure 4. Types of discharge electrodes.

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The plate spacings tested are those most commonly used in Europe and the USA and a wider spacing that permits the evaluation of the operation for applications with a greater saving in internals:

  • 300 mm
  • 400 mm
  • 500 mm

Only those configurations with some interest from the efficiency point of view were tested for fouling and reentrainment. The configurations which get very low particulate matter capture rates or which brought to light serious operational problems were rejected. Thus the final matrix of considered tests out is that shown in Table 3.

Table 3. Test matrix.
 Plate spacing
Type of coalType of electrode300 mm400 mm500 mm
South AfricanBarb   
Pipe and spike   
Twisted rod   
ColombianBarb   
Pipe and spike   
Twisted rod   

RESULTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODOLOGY
  5. PLANNING OF THE TESTS
  6. RESULTS
  7. CONCLUSIONS
  8. ACKNOWLEDGMENT
  9. LITERATURE CITED

For each test performed, the main results collected were the evolution of the electrical variables (V, I, and sparking level), gas flow, extinction and particulate emissions. In this sense, it was possible to monitor the trends over time of these variables and characterize the deterioration of the precipitation operation as the internals were impregnated with stable ash layers. Figure 5 shows an example corresponding to the fouling tests with South African coal and pipe and spike electrode. It can be seen how during the operation of the PESP without rapping of plates and electrodes, the extinction level gradually increases. Thus the cleaning efficiency becomes lower and lower. The evolution of the extinction level shows two different periods. A first stage with a soft increasing is registered. Only same transient puff emissions are detected in this stage. A second stage with a quick increment of the extinction level. A lot of puff emissions occur in this second stage. Figure 5 shows that fluctuations in emissions are greater after 8 h without rapping. When a specific grade of fouling is reached, performance of the ESP becomes unstable with continuous and spontaneous dislodging of thick layers of dust due to gravity and the force of the gas flow.

image

Figure 5. Extinction evolution during a complete fouling test. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

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When the plates and electrodes are rapped at the end of the test, an important increase in extinction peaks for this period is detected, because of the reentrainment due to rapping, but once rapping ceases, the extinction levels decrease sharply. With some configurations, the base level registered at the beginning of the test is recovered. In other cases, when the base level is not recovered, an excessive fouling produces impregnations of ash which are not eliminated by rapping. This implies a decrease in the equipment efficiency.

Rapping reentrainment was monitored during rapping tests. Figure 6 shows the evolution of the extinction, measured by the opacimeter in a rapping test using South African coal and pipe and spike electrode.

image

Figure 6. Extinction evolution during a rapping test. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

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This pattern of behavior, shown in Figures 5 and 6 as an example, is similar in all configurations, although with differences which have been quantified in accordance with the parameters described in the Methodology section.

Fouling and Operational Deterioration

Table 4 shows the main results obtained from the fouling tests. This table shows the particulate emission values at the beginning of the test, with clean plates and electrodes, emission after the period with no rapping, and emission after the final exhaustive rapping of the plates and electrodes. It also shows the characteristic value of the emission growth rate, measured in the linear growth portion of each test. This linear growth in periods with no cleaning by rapping is observed in practically all cases, after an initial period when emission is maintained. However, in some of the tests there was stabilization or sudden decreases in emission at certain points, as a result of the self-cleaning effect which is produced spontaneously if the mass of ash deposited is enough to dislodge the layer by the effect of gravity.

Table 4. Main results of fouling tests.
Type of coalType of electrodePlate spacing (mm)Initial emission (mg/Nm3)Before rapping emission (mg/Nm3)After rapping emission (mg/Nm3)Emission growth rate (%/h)Characteristic time between rapping (min)
South AfricanBarb3003263493340.180
4002752872780.01>120
5003361,3743060.02>120
Pipe and spike3001232812200.2710
4002202932080.1245
5003304153060.06>120
Twisted rod3002083062200.1530
4003061,3344640.6710
ColombianBarb3005175460.0780
4001001101040.02>120
Pipe and spike300104143980.0460
400901201060.01>120
Twisted rod3001101631310.0620

Table 4 also shows the maximum characteristic time. This maximum characteristic time acts as a guide parameter for adjusting the programming of the timing of successive rapping operations in normal continuous operation. It is observed that some of the configurations can last more than 2 h without affecting the efficiency of the filter. Thus, some PESP configurations appears as very insensitive to fouling.

In cases of irregular evolution, the representative values of emission growth rate and characteristic time were always taken in the most unfavorable period, for safety, except in intervals where there was evidence that the irregular evolution was due to other causes than actual fouling of plates and electrodes, such as boiler or preheaters blowing, boiler load movements, start up of mills, and so on.

The most important results derived from Table 4 and the observation of extinction monitoring signal curves are the following:

  • The configurations that show the less effect of fouling due to impregnation with high resistivity coal ash (South African) are those with barb electrodes with spacing of 400 and 500 mm and pipe and spike electrodes with spacing of 500 mm. With low resistivity Colombian coal ash, the configurations with the less effect of fouling are those with barb and pipe and spike electrodes with spacing of 400 mm. None of these configurations showed appreciable changes in electrical variables or in particulate emissions in the first 2 h with no rapping.
  • In configurations with both, barb and pipe-and-spike electrodes, and for both South African and Colombian coal, plate spacing has a clear effect on the tendency to fouling. It is observed that the characteristic time increases as the plate spacing grows. This tendency may be due to the fact that the ash layer adhered to the plates is subject to a weaker electric field when plate spacing grows, and so, the electrostatic pressure over the layer decreases. Thus, the ash layer may be more easily dislodged spontaneously by convective gas flow forces and gravity forces.
  • The low energy electrode (twisted rod) is very sensitive to fouling in the three tests in which it was used. It produces high emission growth rates, some of the lowest characteristic times and, more important, after rapping it does not recover the base emission levels of the beginning of the test. In particular, with Colombian coal with spacing of 300 mm and South African coal with spacing of 400 mm, after continuous rapping, particulate emission levels are 50% higher than the base levels. This means an unacceptable deterioration of precipitation, which may be caused by the formation of stable ash layers, not affected by rapping on the discharge electrodes. If these layers continue to grow, especially when they are formed from high resistivity ash, they will produce a sustained reduction in efficiency with time and may even quench the corona discharges on the discharge electrodes.
  • The rapping efficiency of the pipe and spike electrode is midway between the efficiency of the other types. It shows significant sensitivity to fouling but maintains a good recovery index after rapping and recovers the particulate emission levels present at the beginning of the test (Figure 7). The only exception to this general behavior is the case of the South African coal with spacing of 300 mm, in which it does not recover the base level after rapping having the lowest characteristic time.
  • The estimation of characteristic time gives an idea of the maximum time between rapping operations before the formation of ash layers on the plates and electrodes appreciably deteriorates the precipitation mechanisms. When the characteristic time is high, the rapping times during operation should be determined taking into account the requirements for extracting ash from the equipment, not to overload the extraction systems if rapping occurs at excessively long intervals. However, it should also be taken into account that the characteristic time between rapping determined in a pilot plant will always be greater than that for a real unit, considering the more ideal conditions in the pilot plant.
image

Figure 7. Emission increases after rapping during fouling tests.

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Reentrainment of Particles During Rapping

An important aspect of electrostatic precipitation concerning the electrical sections cleaning is the level of reentrainment that occurs during rapping. When the plates or electrodes are rapped to dislodge the ash, it falls into the hopper in the form of aggregate. A portion of fine particulate matter may be picked up by the gases, producing the reentrainment of dust into the flow, causing a negative effect on performance. This phenomenon mainly happens using low resistivity ash. So, more attention should be paid to the effect of rapping during design and operation of the equipment when utilising high resistivity ash.

The consequences of reentrainment due to rapping on efficiency have been determined, for each configuration, from the peak extinction values at the time of rapping with respect to the base level during previous tests. The existence of these extinction peaks can be seen in Figure 5. Table 5 shows numeric values expressed as the relative increase in emissions over the base level, for the reference test for each series.

Table 5. Results of reentrainment of particles during rapping.
Type of coalType of electrodePlate spacing (mm)Emissions base level (EBL, mg/Nm3)Relative increase in emissions (ΔE, %)
Active fieldsActive fields
123123
South AfricanBarb3001,0484342742.04.03.0
4006894492426.310.95.0
5001,85966136112.938.538.9
Pipe and spike30099837316312.922.633.3
40097240720119.230.028.6
5001,35847124943.632.540.0
Twisted rod3001,04433217213.529.341.7
4001,13846325616.729.734.6
ColombianBarb300188713025.050.035.1
40073332510245.750.036.4
Pipe and spike30091032113145.060.055.0
40053117269104.5128.6400
Twisted rod30057525410065.0116.6400

Attending to reentrainment, the behavior of low resistivity (Colombian) coal is clearly different to high resistivity coal (South African). Low resistivity coal shows higher relative increases in emission level due to reentrainment (Figure 8).

image

Figure 8. Emission increases produced by rapping reentrainment for different electrode types.

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The behavior of the different configurations with regard to rapping can be summarized as follows:

  • In the tests of high resistivity (South African) coal with barb electrodes and spacing of 300 and 400 mm, the effects of rapping on emission levels can be considered low. Thus, it can be deduced that reentrainment has a negligible effect on emission levels. With 300 mm spacing, no significant increases of emission on rapping the electrical fields were observed. In tests using barb electrodes and 400 mm spacing, there is only a slight increase in the amplitude of extinction fluctuations on rapping the third field. However, considering spacing of 500 mm and the other electrodes, there are significant extinction increases, up to 40% compared to the base level.
  • For low resistivity coal (Colombian), it can be seen that rapping causes important levels of reentrainment of dust into the gas stream. In general, reentrainment is higher considering rapping electrodes instead of rapping plates, especially in the last field. On some occasions, the extinction peaks due to rapping reentrainment cause increases in emissions which are over 100% of the average baseline levels, which gives an idea of the relative importance of the proportion of reentrained particulate matter on the emissions recorded at the moment of rapping.
  • An increase in plate spacing with the same type of electrode always produces an increase in the absolute reentrainment value, for both high and low resistivity coals. This result could be a consequence of a diminution of the electrical field strength [9]. As a result, the use of larger plate spacings makes necessary to modify the average design performance value, to introduce the effect of reentrainment on the overall level of emissions and, where necessary, to compensate this loss of efficiency with an additional increase in the specific capture area (SCA), to avoid the appearance of peaks of emissions which exceed maximum limits during rapping.
  • With respect to the electrodes, the highest absolute reentrainment values occur with the twisted rod electrode, followed by the pipe and spike electrode and by the barb electrode with a much lower value.
  • Taking into account the rise in extinction, which measures the importance of reentrainment due to rapping, it is observed in general terms that high relative increases in emissions correspond with low emissions base levels. This way, peaks of low value mean relative increases of 400% over the baseline level when using Colombian coal, especially with pipe and twisted rod electrodes. However, there are exceptions such as South African coal, spacing of 500 mm and pipe and spike electrode in which the higher emissions base level, the greater relative increases. In any case, both magnitudes, emissions base level and relative increase, should be taken into account when designing or remodelling an ESP.

CONCLUSIONS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODOLOGY
  5. PLANNING OF THE TESTS
  6. RESULTS
  7. CONCLUSIONS
  8. ACKNOWLEDGMENT
  9. LITERATURE CITED

The above results make possible to reach the following main conclusions:

  • High resistivity ash produces, in general, and specially for those configurations that achieve a high current density (high energy electrodes combined with low plate spacings), greater fouling by stable layers of ash than with low resistivity ash. With the same electrode and plate spacing, the electrofiltration operation deteriorates more quickly with high resistivity ashes if rapping is halted. It is therefore necessary to use more energetic and more continuous rapping when operating with this type of ash.
  • The increase of plate spacing for the same type of electrode gives a lower risk of fouling, more evident for high resistivity ash from South African coal. However, and particularly with low resistivity ash, an increase in plate spacing gives rise to important increases of reentrainment due to rapping.
  • Low resistivity ash produces much higher reentrainment due to rapping considering the same type of electrode. The less sensitive internal configuration for this type of ash is that using a high-energy electrode. Low and medium energy electrodes produce reentrainment of up to 400% over the extinction baseline.
  • The low energy electrode is not recommended for design, from the point of view of both fouling and reentrainment. Both problems are more serious with this type of electrode.
  • If there are constant changes of fuel producing ashes of different resistivities, it is advisable to design the ESP with a high-energy electrode and a medium plate spacing of around 400 mm. The high-energy electrode gives higher efficiency than the others for both high and low resistivity ashes.

ACKNOWLEDGMENT

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODOLOGY
  5. PLANNING OF THE TESTS
  6. RESULTS
  7. CONCLUSIONS
  8. ACKNOWLEDGMENT
  9. LITERATURE CITED

The authors wish to express their sincere thanks to the technical personnel of the Los Barrios Coal Power Plant for the use of their facilities and their cooperation in the development of these tests.

LITERATURE CITED

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODOLOGY
  5. PLANNING OF THE TESTS
  6. RESULTS
  7. CONCLUSIONS
  8. ACKNOWLEDGMENT
  9. LITERATURE CITED
  • 1
    Spencer, H.W. (1976) Rapping reentrainment in a nearly full-scale pilot electrostatic precipitator. EPA Tech. Rep. No. 600/2-76-140, Environmental Protection Agency, USA.
  • 2
    Juricic, D., & Herrmann, G. (1976). Response of collecting plates in electrostatic precipitators due to shear rapping. Journal of Mechanical Design, 100, 105112.
  • 3
    Juricic, D., & Herrmann, G. (1978). Modelling and simulation of dust dislodgement on collecting plates in electrostatic precipitators. Modelling and Simulation (Volume 9), Part 1, 161166, Proceedings of the 9th Annual Pittsburgh Conference, Published: Instrument Society of America.
  • 4
    White, H.J. (1963). Industrial electrostatic precipitation, Reading, MA: AddisonWesley.
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    Parker, K.R. (1997). Applied electrostatic precipitation, London: Chapman & Hall.
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    Böhm, J. (1982). Electrostatic precipitators, New York: Elsevier.
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    Neundorfer, M. (1981). Electrode cleaning systems: Optimizing rapping energy and rapping control. Environmental International, 6, 279287.
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    Xu, D., Li, J., Wu, Y., Wang, L., Sun, D., Liu, Z., & Zhang, Y. (2003). Discharge characteristics and applications for electrostatic precipitation of direct current: Corona with spraying discharge electrodes. Journal of Electrostatics, 57, 217224.
  • 9
    Dai, Y., & Huang, K. (2008). Analytical study on ZT collecting electrode, Proceedings of 11th International Conference on Electrostatic Precipitation (pp. 175178), Hangzhou, China.
  • 10
    Francis, S.L., Bäck, A., & Johansson, P. (2008). Reduction of rapping losses to improve ESP performance. Proceedings of the 11th International Conference on Electrostatic Precipitation (pp. 45–49), Hangzhou, China.
  • 11
    Lee, J-K., Ku, J-H., Lee, J-E., Kim, S-C., Ahn, J-H., & Choung, S-H. (1998). An experimental study of electrostatic precipitator plate rapping and reentrainment, Proceedings of the 7th International Conference on Electrostatic Precipitation, Kyongju, Korea.
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    Yamamoto, T., Mitsuhiro, M., & Shibata, K. (1998). Studies of rapping reentrainment from electrostatic precipitators, Proceedings of the 7th International Conference on Electrostatic Precipitation, Kyongju, Korea.
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    Self, S.A., & Moslehi, G.B. (1981). Electromechanics and reentrainment of precipitated ash, Proceedings of the International Conference on Electrostatic precipitation (pp. 399–440), Monterey, CA.
  • 14
    Bush, V.P. (1984). Study of rapping reentrainment emissions from a pilot-scale electrostatic precipitator. Environmental Science & Technology, 18, 699705.
  • 15
    Jedrusik, M., Swierczok, A., & Teisseyre, R. (2003). Experimental study of flay ash precipitation in a model electrostatic precipitator with discharge electrodes of different design. Powder Technology, 135136, 295–301.
  • 16
    Jedrusik, M., & Swierczok, A. (2009). The influence of fly ash physical and chemical properties on electrostatic precipitation process. Journal of Electrostatics, 67, 105109.
  • 17
    Cañadas, L., Ollero, P., Salvador, L., Galindo, J. (1994). A flue gas desulphurisation and electrofiltration pilot plant: Design and objectives. Proceedings of the 3rd Florence world energy research symposium, Energy for the 21st century: Conversion, utilisation and environmental quality (pp. 745–763), Padova: SG Editoriali.