FI20245093A1

FI20245093A1 - Electrostatic precipitator and cyclone separator including an electrostatic precipitator

Info

Publication number: FI20245093A1
Application number: FI20245093A
Authority: FI
Inventors: Sampo Saari
Original assignee: Aeroff Oy
Priority date: 2024-01-31
Filing date: 2024-01-31
Publication date: 2025-08-01
Also published as: EP4596108A1

Abstract

Keksintö koskee sähkösyklonierottimen sähkösuodatinta (ESP), joka käsittää ainakin kolme samanmuotoista ja sisäkkäistä keruulevyä, joilla on sama muoto, jolloin ainakin yksi samanmuotoista ja sisäkkäisistä keruulevyistä on HV-keruulevy, joka on liitetty suurjännitteeseen ja joka HV-keruulevy on järjestetty sijoitettavaksi kahden maatetun GND-keruulevyn väliin. Keksintö koskee lisäksi aerosolin puhdistusmeneteThe invention relates to an electrostatic precipitator (ESP) of an electrocyclone separator, comprising at least three identically shaped and nested collection plates having the same shape, wherein at least one of the identically shaped and nested collection plates is an HV collection plate connected to a high voltage and each HV collection plate is arranged to be placed between two grounded GND collection plates. The invention further relates to an aerosol purification method

Description

An electrostatic precipitator and an electro-cyclone separator comprising an electrostatic precipitator

Technical field

The present invention relates to an electrostatic precipitator and an electro- cyclone separator comprising an electrostatic precipitator.

The invention also relates to a method for removing gaseous and particulate impurities from aerosol by an electro-cyclone separator comprising an electrostatic precipitator.

Background

Aerosol consists of gaseous compounds and solid or liquid particles suspended in a gas i.e. itis a suspension of fine solid particles or liquid droplets in air or another type of gas. Aerosols can be natural or anthropogenic.

Industry, power plants and various combustion processes are examples, which generate harmful gases and particles that are removed from the process before they are released into the environment.

An electrostatic precipitator (ESP) is a device often used in removing harmful gases and particles in industry, power plants and various combustion processes. The ESP produces an electric corona discharge, which produces electrical charges that adhere to the aerosol particles, which are then collected from the aerosol by an electric field. The ESP enables the separation of both

N large and small particles. A typical problem with ESPs is the accumulation of

N dust in the collector plates, which leads to malfunction of the ESP. Another

O problem is the accumulation of dust on the corona discharge electrode, which e 30 also leads to malfunction of the ESP. 7

NN Summary > a It is the aim of the invention to provide and present an electrostatic precipitator

R 35 comprising collector plates configured to remove gaseous and particulate impurities from aerosol. A further aim is to provide a method for removing gaseous and particulate impurities from aerosol by an electro-cyclone separator. The scope of protection sought for various embodiments of the invention is set out by the independent claims. The embodiments, examples and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the invention.

According to a first aspect, there is provided an electrostatic precipitator (ESP) for an electro-cyclone separator comprising at least three uniform and nested collector plates having a uniform form. At least one of the uniform and nested collector plates is a HV collector plate that is connected to high voltage and is configured to be arranged between two grounded GND collector plates of the at least three uniform and nested collector plates.

According to an embodiment, the electrostatic precipitator comprises more than three uniform and nested cylindrical collector plates so that every other cylindrical collector plate is a cylindrical HV collector plate arranged between two grounded cylindrical GND collector plates. According to an embodiment, the electrostatic precipitator comprises a corona discharger unit, which is kept clean by a clean aerosol flow that is circulated from cleaned gas flow or from outside of the process. According to an embodiment, the shape of the electrostatic precipitator is annular having cylindrical collector plates.

According to an embodiment, the shape of the electrostatic precipitator is rectangular, pentagonal, hexagonal, heptagonal, or octagonal. According to an embodiment, the electrostatic precipitator further comprises cleaning means for cleaning the cylindrical collector plates, wherein the cleaning means is an acoustic resonator.

S

N According to a second aspect, there is provided an electro-cyclone separator

O comprising an electrostatic precipitator (ESP) according to the first aspects m 30 and its embodiments and a cyclone for removing large particles of inlet aerosol. 7

N According to an embodiment, the shape of the cyclone is rectangular, 2 pentagonal, hexagonal, heptagonal, or octagonal.

N

R 35 According to a third aspect, there is provided an aerosol purification method at least comprising supplying aerosol comprising particles into an electro-cyclone separator, charging aerosol particles by a corona discharger unit of an electrostatic precipitator (ESP) according to any of the claims 1 to 6, if the input aerosol is not already naturally charged, removing large aerosol particles by a cyclone, and removing small particles by an electrostatic precipitator by the electrostatic precipitator.

According to an embodiment, the method further comprises circulating cleaned aerosol flow to the corona discharger unit, if the input aerosol is not already naturally charged. According to an embodiment, the circulated aerosol flow is 1-20% of the total cleaned aerosol flow amount. According to an embodiment, the circulated aerosol flow is circulated using blower, venturi or ejector.

According to an embodiment, the method further comprises outputting the cleaned aerosol from the electro-cyclone separator. According to an embodiment, the method further comprises performing a cleaning process for circular collecting plates of the electrostatic precipitator, regularly or if needed, by an acoustic resonator. According to an embodiment, the method further comprises removing dust from the cyclone through an outlet at the bottom of the cyclone.

Brief description of the drawings

In the following, the invention will be described in more detail with reference to the appended drawings, in which

Fig. 1 shows from above an annular ESP according to an embodiment of the invention,

N Fig. 2 shows from above an annular ESP according to an embodiment

N of the invention,

S m 30 Fig. 3 shows a cross-sectional view of an electro-cyclone separator = according to an embodiment of the invention, a & Fig. 4 shows a cross-sectional view of an electro-cyclone separator 3 according to an embodiment of the invention, & 35

Fig. 5 shows a cross-sectional view of an electro-cyclone separator according to an embodiment of the invention,

Fig. 6 shows method steps performed by an electro-cyclone separator according to an embodiment of the invention,

Fig. 7 shows process steps performed by an electro-cyclone separator according to an embodiment of the invention in a simplified manner,

Fig. 8 shows from above a rectangular ESP according to an embodiment of the invention,

Fig. 9 shows from above a pentagonal ESP according to an embodiment of the invention, and

Fig. 10 shows from above a hexagonal ESP according to an embodiment of the invention.

Detailed description

Aerosol consists of gaseous compounds and solid or liquid particles suspended in a gas meaning that aerosol is a suspension of fine solid particles or liquid droplets in air or another type of gas. In the present application, the terms “aerosol”, “aerosol flow”, “gas flow”, “air”, and “air flow” have the same meaning i.e. to refer the aerosol to be cleaned if not otherwise indicated. An electrostatic precipitator (ESP) is a device often used in removing harmful gases and particles in industry, power plants and various combustion

N processes. The operation is based on three major factors: particle charging,

N electrostatic collection of charged particles and removal of collected particles.

O The ESP first produces an electric corona discharge, which produces electrical m 30 charges that adhere to the aerosol particles. The charged particles are then = collected from the aerosol by an electric field formed between collector plates of the ESP. The ESP enables the separation of both large and small particles.

S Electrostatic precipitation has generally been used in the particle size range a 0.1 - 10 um. However, accumulation of dust in the collector plates and/or

R 35 corona discharge electrode of ESPs cause problems, which leads to malfunction of the ESP. In order to maintain the function of an ESP, its collector plates and/or corona discharge electrode should be kept clean.

A cyclone separator is a separation device that uses the principle of inertia to remove particles from flue gases or other aerosols. The cyclone comprises a cylindrical part and a cyclone part below the cylindrical part. Cyclone 5 separators are some of several air pollution control devices usually known as pre-cleaners because they mainly remove larger particles of the aerosol.

Cyclone separators are used in an earlier stage than ESPs. They prevent finer filtration methods, for example just as already mentioned ESPs from having to deal with larger, more abrasive particles in a later stage. Whereas an electro- cyclone separator is a combination of a cyclone separator and an ESP in the same unit that removes particles in the wide size range also in a dirty and wet environment for long time.

The electro-cyclone separator of the present invention is a combined particle removal system comprising an annular ESP comprising cylindrical collector plates placed inside the electro-cyclone separator and a cyclone arranged below the ESP. In the purifying process the cyclone is before the ESP and it removes most of the large particles before the aerosol reaches the annular

ESP. The ESP itself has two stages; a corona discharger unit arranged before cylindrical electrostatic collector plates. Aerosol particle electrical charging is done using the corona discharger unit before the collector plates of the ESP.

One or more corona discharger(s) of the corona discharger unit of the ESP produce an electric corona discharge that adhere to the aerosol particles. Each corona discharger unit may comprise one or more corona needles. The corona discharger unit may be placed in various places, for example in the middle of the ESP so that it extends below the bottom of the ESP, underneath and on

N the side of the ESP, or near the inlet of the electro-cyclone separator. It should

N be noted that aerosol particles may not need to be charged by an air flow

O protected corona discharger unit, if the input aerosol particles are already m 30 naturally charged particles. 7

N The charged particles are then collected from the inlet aerosol by an electric 2 field formed between cylindrical collector plates i.e. cylinders of the ESP. The 3 geometry of internal cylinders provides annular electric fields for electrostatic precipitation of particles. A DC high voltage, for example typically 5-50 kV, is, for example in a case of three cylindrical collector plates, connected to a cylindrical HV collector plate arranged in the middle i.e. between two GND cylindrical collector plates, which are cylindrical collector plates connected to ground. A strong electric field will be formed between a cylindrical HV collector plate and cylindrical GND collector plates. It is obvious that the annular ESP may have more than three internal cylinders. If there are more than three cylindrical collector plates, then every other cylindrical collector plate is so called cylindrical HV collector plate, which is connected to DC high voltage and arranged between two cylindrical GND collector plates that are grounded.

Material of cylindrical HV or GND collector plates may be, for example steel.

The cylindrical shape of collector plates of the ESP enables an aerosol particle collector structure without leaks in the electric field, so the particle collection efficiency is higher. This is because the geometry formed by internal cylinders of the ESP according to the present invention allows enhanced performance and lower residence time for particle collection in the electric field, which means that air is cleaned more effectively. The cylindrical collector plates are insulated from each other, for example by using insulation bolts, which may be made of, for example high resistive insulator material(s), such as PTFE.

The ESP may also have another shape instead of the cylindrical shape, for example a rectangular, pentagonal, hexagonal, heptagonal, or octagonal etc. shape. Collector plates have a corresponding shape as the ESP so that when the ESP has a cylindrical shape the collector plates also have a cylindrical shape, or when the ESP has a rectangular shape the collector plates also have a rectangular shape, or when the ESP has a pentagonal shape the collector plates also have a pentagonal shape etc.. The cyclone may also have corresponding shapes as the ESP when seen above ie. cylindrical,

N rectangular, pentagonal, hexagonal, heptagonal, or octagonal shape. For

N example, the shapes of the ESP and the cyclone may, but not necessarily,

O correspond each other so that when the ESP has a cylindrical shape the m 30 cyclone also has a cylindrical shape, or when the ESP has a rectangular shape = the cyclone also has a rectangular shape, or when the ESP has a pentagonal shape the cyclone also has a pentagonal shape etc. $ a The corona discharger unit may be protected and/or kept clean by clean air

R 35 flow that is circulated from cleaned gas flow or from outside of the process i.e. corona discharger unit may be protected and/or by sheath flow. The circulated air flow may be, for example about 1-20% of the total cleaned inlet airflow. This kind of solution may be called as an air protected corona discharger unit.

However, providing of clean air flow to the corona discharger unit can be done in different ways, for example, there may be a cavity inside the ESP for an air flow to be supplied for a corona discharger unit or there may be a pipe or corresponding that is arranged outside the ESP for supplying air flow to corona discharger unit. In addition, instead of recirculated cleaned air outside air can be added to the process and provide it for the corona discharger unit. Clean air flow can be blown i.e. supply for the corona discharger unit, for example by a blower, venturi or ejector or any other suitable means.

The annular ESP may further be equipped with cleaning means of collector plates that enables low maintenance. The cleaning may be carried out regularly or when needed. Cleaning means may be any suitable means such as an acoustic resonator, hammer, pressure impulse, mechanical brush or washing means. Dust collected in a cyclone can be removed from the cyclone, for example through an outlet arranged in the bottom of the cyclone.

The above mentioned characteristics of the electro-cyclone separator comprising a cyclone, an annular ESP, an air protected corona discharger unit, or cleaning means of collector plates or one or more of their combinations enable high particle removal efficiency in a wide particle size range for dirty and wet aerosol emission. The cleaning of collector plates and air protected corona discharger unit enable long-term operation with low maintenance.

Thus, an annular ESP integrated inside the cyclone structure enables not only a compact size for a particle removal unit, but also high efficiency.

N Figure 1 shows from above an annular ESP 100 according to an embodiment

N of the invention. The annular ESP 100 is suitable to be used in an electro-

O cyclone separator according to an embodiment of the invention, but also as m 30 such or in connection with other gas purifying devices. The annular ESP 100 = of figure 1 comprises three cylindrical collector plates 101, 102 each having a uniform cylindrical form. One of them is a cylindrical HV collector plate 101 that

S is arranged between two cylindrical GND collector plates 102. The cylindrical 3 collector plates 101, 102 are insulated from each other. The cylindrical collector plates 101, 102 are fixed in place inside the ESP 100 and insulated from each other by fixing them to insulating means 104, which are, for example insulating brackets or any other suitable means. By a reference number 103 is indicated a wall of a cylindrical part 103 of the electro-cyclone separator inside which the annular ESP 100 is suitable to be used.

In the middle of the annular ESP 100, inside all the cylindrical collector plates 101, 102, is a corona discharger unit 105. The corona discharger unit 105 first produces an electric corona discharge, which produces electrical charges that adhere to the aerosol particles, which are then collected from the aerosol by an electric field formed between the cylindrical collector plates 101, 102. The corona discharger unit 105 may reach as far down as the bottom surface of the annular ESP 100, but it is also possible that it extends some extent below the bottom of the annular ESP 100, for example some centimetres to tens of centimetres. The center of the annular ESP 100 i.e. the area above and around the corona discharger unit 105 is a hollow space like a cavity, which has an open top and through which clean air can be supplied for the corona discharger unit 105 for keeping it clean. The corona discharger unit 105 may comprise at least one corona charge needle, which is toward the ground i.e. downwards.

The annular ESP 100 further comprises cleaning means 106, which in this embodiment is an acoustic resonator, which cleans the cylindrical collector plates 101, 102 by resonating the cylindrical collector plates 101, 102 acoustically. The cleaning means 106 may be fixed to the annular ESP 100 or connected to the annular ESP 100 when needed. The cleaning means 106 are optional.

Figure 2 shows from above an annular ESP 200 according to an embodiment of the invention. The annular ESP 200 is also suitable to be used in an electro-

N cyclone separator according to an embodiment of the invention, but also as

N such or in connection with other aerosol purifying devices. This annular ESP

O 200 comprises five nested cylindrical collector plates 201, 202 each having a m 30 uniform cylindrical form. The cylindrical HV collector plates 201 are arranged = between two cylindrical GND collector plates 202. By a reference number 203 is indicated a wall of a cylindrical part 103 of the electro-cyclone separator.

S The cylindrical collector plates 201, 202 are fixed in place inside the ESP 200 3 and insulated from each other by fixing them to insulating means 204, which are, for example insulating brackets or any other suitable means.

In the middle of the annular ESP 200 and its nested cylindrical collector plates 201, 202 is again a corona discharger unit 205 that may extend as low as the bottom surface of the annular ESP 200 or some extent lower than the annular

ESP 200, for example some centimetres to tens of centimetres. The area above and around the corona discharger unit 205 is hollow and it is suitable for providing air from above for the corona discharger unit 205. The corona discharger unit 205 may comprise at least one corona charge needle.

The annular ESP 200 further comprises cleaning means 206 for cleaning the cylindrical collector plates 201, 202. The cleaning means 206, which may be, for example an acoustic resonator, hammer, pressure impulse, mechanical brush or washing means is optional.

Figures 3-5 show cross-sectional views of electro-cyclone separators 300, 400, 500 according to an embodiment of the invention, the electro-cyclone separators 300, 400, 500 have a little different structures compared to each other.

Figure 3 shows a cross-sectional view of the electro-cyclone separator 300, which comprises an annular ESP 301, a cyclone 302, an inlet 305 for an aerosol flow to be purified i.e. cleaned, an outlet 306 for purified i.e. cleaned air flow, and a dust outlet 307 in the bottom of the cyclone 302. The annular

ESP 301 is placed inside the electro-cyclone separator 300, more precisely inside a cylindrical part 303 of the electro-cyclone separator 300 and the cyclone 302 is in a cyclone part 304 of the electro-cyclone separator 300 that is below the cylindrical part 303. The annular ESP 301 comprises cylindrical

N collector plates 308 i.e. cylinders, a corona discharger unit 309, and insulating

N means 204310. The high voltage is connected to every other cylinder and other

O cylinders are connected to the ground. n 30 = In this embodiment of figure 3, the inlet 305 is in the upper part of the electro- cyclone separator 300. In the electro-cyclone separator 300, dirty aerosol

S comprising particles of different sizes is fed into the electro-cyclone separator 3 300 through the inlet 305 and inside of the electro-cyclone separator 300 a spiral vortex is formed around the ESP 301 downwards. The corona charging unit 309 below the middle part of the ESP 301 charges the particles of the dirty inlet aerosol in the vicinity of the corona charging unit 309 i.e. in its influence area. Then the lighter particles of this inlet gas, which have less inertia, are influenced by the vortex and they travel up towards the annular ESP 301, the direction is shown by bending arrays 311. The ESP 301 removes the lighter particles from the gas by an electric field formed between the plates 308.

Larger particles have difficulty following the high-speed spiral motion of the gas and the vortex, therefore the larger particles hit the inside walls of the cyclone 302 of the electro-cyclone separator 300 and drop down to be cleaned through the dust outlet 307 in the bottom of the cyclone 302.

Clean recirculated air flow 312 that is a part of ESP 301 cleaned air flow is supplied after the annular ESP 301 down towards the corona discharger unit 309, for example by a blower, venturi or ejector or any other suitable means.

The non-recirculated part of the cleaned air flow is led outside from the electro- cyclone separator 300 through the outlet 306.

Figure 4 shows a cross-sectional view of the electro-cyclone separator 400, which differs from the electro-cyclone separator 300 of figure 3 in that its corona discharger unit 409 is in the side of the lower part of a cylindrical part 403 of the electro-cyclone separator 400, underneath the annular ESP 401, but above the cyclone 402. The center part of the annular ESP 401 is gas- closed. The clean recirculated air flow 412 is provided for the corona discharger unit 409, for example by a blower, venturi or ejector or any other suitable means, through a separate pipe 413 arranged outside the electro- cyclone separator 400. Insulator bolts of the annular ESP 401 are not shown in this figure 4.

N Figure 5 shows a cross-sectional view of the electro-cyclone separator 500,

N which differs from the electro-cyclone separators 300 and 400 in that its corona

O discharger unit 509 is placed above the cylindrical part 503 of the electro- m 30 cyclone separator 500 i.e. in the upper part of the electro-cyclone separator = 500. It is in the route of an aerosol flow to be purified that is fed to the electro- cyclone separator 500 through an aerosol inlet 505 so that it can charge

S aerosol particles of the aerosol flow. Insulator bolts 510 of the annular ESP 3 501 are shown in this figure 5. & 35

As mentioned, also in both electro-cyclone separators 400 and 500 the corona charging units 409, 509 charge the particles of the dirty inlet aerosol passing by them. Then the lighter particles of this inlet gas travel up towards the annular

ESPs 401, 501. These ESPs 401, 501 remove the charged lighter particles from the gas by electric fields formed between the cylindrical collector plates.

Larger particles of the inlet gas are dropped down to the bottom of the electro- cyclone separators 400 and 500 to be cleaned through the dust outlet in the bottom of the electro-cyclone separators 400 and 500.

Clean recirculated air flow 512 that is a part of cleaned air flow is supplied after the annular ESP 501 for the corona discharger unit 509, for example by a blower, venturi or ejector or any other suitable means. The non-recirculated part of the cleaned air flow is let outside from the electro-cyclone separator through the outlet. The annular ESPs 301, 401, 501 of the electro-cyclone separators 300, 400 and 500 may further comprise cleaning means for cleaning the cylindrical collector plates of the annular ESPs 301, 401, 501.

In some circumstances, electro-cyclone separators may need a fan or corresponding to push the aerosol to be cleaned towards annular ESPs, but in some circumstances, for example in a case of a hot fuel gas as an inlet aerosol, the inlet aerosol rises upwards without a fan.

Figure 6 shows a block diagram of an aerosol purification method 600. In step 610, aerosol is inputted i.e. dirty gas flow is fed to an electro-cyclone separator.

In step 620, aerosol particles are charged by a corona discharger unit, if the input aerosol is not already naturally charged. In step 630, large aerosol particles, for example >10 um are removed by a cyclone in a known manner of the field. In step 640, small particles, for example <10 um are removed by

N an annular electrostatic precipitator. In step 650, a part of the cleaned air, for

N example 1-20% of the total cleaned air amount is circulated to the corona

O discharger unit as a protective sheath using e.g. blower, venturi or ejector. If m 30 the input aerosol is already naturally charged, this step 650 is not necessary. = In step 660, cleaned aerosol is outputted from the electro-cyclone separator.

The method may further comprise the following steps; performing a cleaning

S process for circular collecting plates of the annular electrostatic precipitator, 3 regularly or if needed, with an acoustic resonator, hammer or by washing, and/or removing dust from the cyclone through an outlet at the bottom of the cyclone.

Figure 7 shows process steps performed by an electro-cyclone separator according to an embodiment of the invention in a simplified manner. In process step 1, aerosol is fed in. In process step 2, aerosol particles are charged. In process step 3, large aerosol particles are removed by a cyclone. In process step 4, small aerosol particles are electrostatically precipitated by an annular

ESP. In process step 5, which is optional, a part of the cleaned air is used to provide clean air i.e. a so called protective sheath flow for corona charging means i.e. a corona discharger unit. In process step 6, cleaned aerosol is outputted.

Figure 8 shows from above a rectangular ESP 800 according to an embodiment of the invention. The rectangular ESP 800 comprises three rectangular collector plates 801, 802 each having a uniform and continuous rectangular form. One of them is a rectangular HV collector plate 801 that is arranged between two rectangular GND collector plates 802.

Figure 9 shows from above a pentagonal ESP 900 according to an embodiment of the invention. The pentagonal ESP 900 comprises three pentagonal collector plates 901, 902 each having a uniform and continuous pentagonal form. One of them is a pentagonal HV collector plate 901 that is arranged between two pentagonal GND collector plates 902.

Figure 10 shows from above a hexagonal ESP 1000 according to an embodiment of the invention. The hexagonal ESP 1000 comprises three hexagonal collector plates 1001, 1002 each having a uniform and continuous hexagonal form. One of them is a hexagonal HV collector plate 1001 that is

N arranged between two hexagonal GND collector plates 1002.

N

O As explained above, considerable advantages are achieved by the present m 30 invention when compared to existing aerosol cleaning methods and aerosol = cleaning devices and systems. These advantages are achieved by combining certain features of ESP and cyclone. Longer residence time of target gas

S molecules and particles in the electric fields formed by cylindrical collector 3 plates enhances the collection of charged particles from the inlet aerosol that is precleaned by the cyclone. Further, an electro-cyclone separator is also affordable to implement because it is a compact and an efficient solution of removing particles having a wide size range.

However, it should be noted that the shape of the annular ESP may in some cases be, for example oval, rectangular, pentagonal, hexagonal, etc. instead of an annular cylindrical shape, but in any case there are at least three nested collector plates of which every other one is always a HV collector plate and every other one is a GND collector plate. An ESP for an electro-cyclone separator comprises at least three uniform and nested collector plates having a uniform form, which uniform form means in this connection that they have continuous structure. However, nested collector plates have different sizes i.e. cross section sizes so that they fit in the nested like form, one inside the other.

The place of the corona discharger unit in an electro-cyclone separator may be before or after the cyclone. If it is arranged before the cyclone i.e. the aerosol to be cleaned reaches the cyclone before the corona discharger unit, the residence time of the particles of the aerosol increases. Whereas, if the aerosol to be cleaned reaches the corona discharger unit before the cyclone, then the probability of contamination of the corona discharger unit increases.

It is obvious that the present invention is not limited solely to the above- presented embodiments, but it can be modified within the scope of the appended claims. <

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Claims

Claims:

1. An electrostatic precipitator (ESP) for an electro-cyclone separator comprising at least three uniform and nested collector plates having a uniform form, wherein at least one of the uniform and nested collector plates is a HV collector plate that is connected to high voltage and which HV collector plate is configured to be arranged between two grounded GND collector plates.

2. The electrostatic precipitator (ESP) according to claim 1, wherein the electrostatic precipitator comprises more than three uniform and nested cylindrical collector plates so that every other cylindrical collector plate is a cylindrical HV collector plate arranged between two grounded cylindrical GND collector plates.

3. The electrostatic precipitator (ESP) according to claim 1 or 2, wherein the electrostatic precipitator comprises a corona discharger unit, which the corona discharger unit is kept clean by a clean aerosol flow that is circulated from cleaned gas flow or from outside of the process.

4. The electrostatic precipitator (ESP) according to any of the claims 1 to 3, wherein the shape of the electrostatic precipitator is annular having cylindrical collector plates.

5. The electrostatic precipitator (ESP) according to any of the claims 1 to 3, wherein the shape of the electrostatic precipitator is rectangular, pentagonal, hexagonal, heptagonal, or octagonal. S

N 6. The electrostatic precipitator (ESP) according to any of the claims 1 to 5, O wherein the electrostatic precipitator further comprises cleaning means for m 30 cleaning the cylindrical collector plates, wherein the cleaning means is an = acoustic resonator. a

3 7. An electro-cyclone separator comprising an electrostatic precipitator (ESP) a according to any of the claims 1 to 6 and a cyclone for removing large particles N 35 of inlet aerosol.

8. An electro-cyclone separator according to claim 7, wherein the shape of the cyclone is rectangular, pentagonal, hexagonal, heptagonal, or octagonal.

9. An aerosol purification method comprising: supplying aerosol comprising particles into an electro-cyclone separator, charging aerosol particles by a corona discharger unit of an electrostatic precipitator (ESP) according to any of the claims 1 to 6, if the input aerosol is not already naturally charged, removing large aerosol particles by a cyclone, and removing small particles by an electrostatic precipitator by the electrostatic precipitator.

10. An aerosol purification method according to claim 9, wherein the method further comprises: circulating cleaned aerosol flow to the corona discharger unit, if the input aerosol is not already naturally charged.

11. The aerosol purification method according to claim 10, wherein the circulated aerosol flow is 1-20% of the total cleaned aerosol flow amount.

12. The aerosol purification method according to claim 10 or 11, wherein the N circulated aerosol flow is circulated using blower, venturi or ejector. & O

13. An aerosol purification method according to any of claims 9-12, wherein m 30 the method further comprises: = outputting the cleaned aerosol from the electro-cyclone separator. a O 2

14. An aerosol purification method according to any of claim 9-13, wherein the 3 method further comprises: performing a cleaning process for circular collecting plates of the electrostatic precipitator, regularly or if needed, by an acoustic resonator.

15. An aerosol purification method according to any of claims 9-14, wherein the method further comprises: removing dust from the cyclone through an outlet at the bottom of the cyclone. i N O N S ™ I = O oO O LO + N oo Al