EP2195115B1 - Physical structure of exhaust-gas cleaning installations - Google Patents

Abstract

A waste-gas cleaning system for cleaning aerosol-laden gases or atmospheres includes an inlet configured to intake raw gas, an outlet configured to discharge clean gas and at least one assembly including an ionization section and a downstream central collection section disposed centrally with respect to a channel axis. The ionization section includes at least one level at a right angle to the channel axis. The at least one assembly includes at least two substantially identical ionization stages disposed in a plane and arranged uniformly about the channel axis and configured to conduct a gas flow radially, with respect to the channel axis, inward therethrough into the downstream central collection section so as to be similarly diverted such that a flow profile over an inside cross section in the downstream central collection section is not inclined with respect to the channel axis in the course of the gas flow.

Description

The invention relates to the structure of emission control systems for cleaning aerosols loaded gases or atmospheres and types of emission control systems having such a structure. The invention is to be embedded in the technology of electrostatic particle separation, in particular of a space-charge-type electrostatic particle separator. In a space charge separator unipolar charged particles are deposited according to the field of their own space charge [1].

Depending on the structural design of the separator, the self-separation in a wet scrubber within the tubular electrodes takes place in a filter. Wet scrubbers have provided a useful improvement in efficiency in which the particles / aerosols are loaded prior to entering the scrubber. Charged particles are separated by the wet scrubbing process and the electrostatic deposition under the influence of the space charge.

An electrostatic precipitator also operates on the principle of mutual repulsion of the charged particles on a wall to reference potential, preferably ground potential. As the charged particles pass through the grounded portion of a precipitator, a portion of the charged particles are forced to the grounded wall by the electric field generated by the space charge. Deposited particles are entrained and discharged in the co-flowing water flowing down the walls of the grounded tube electrodes.

In an ionizing wet scrubber (see for example DE 22 35 531 ), a gas stream to be processed is ionized prior to its passage through the wet scrubber to provide the particles / aerosols in the gas stream with an electrical charge of predetermined polarity. During the flow of the gas stream, the charged particles / aerosols become close to the scrubber liquid and / or packing elements as an effect of the attractive forces between the charged particles and the electrically neutral packing elements and the liquid carried. The particles are removed from the gas stream through the scrubber liquid.

A particle of ionizing scrubber (see for example US Apl. Publ. 2006/0236858 A1 consists of a charge and collector section. The collector consists of either a fixed or liquid bed packed section, which is irrigated continuously from above. The gas stream and the charged particles are transported directly from the charging means to the collector means and the clean gas then passes through a liquid separator to remove liquid droplets.

The described separator have a collection chamber between the charging device and the collector device, therefore, the space charge distribution at the collector input is homogeneous. The direction of the gas flow at the inlet and at the outlet of the collector is the same.

There are electrostatic space charge separators without collecting chamber between the charging device and the collector device (see for example U.S. 4,072,477 or DE 10 2006 055 543 ). In this case, the output of the charging device is attached to a chamber which has electrically conductive packing material, for. B. tower packing elements. The direction of the gas flow at the entrance and exit is either the same or the gas flow changes direction within the collector means. In the latter case, the space charge distribution in the input area of the collector is not homogeneous. It is maximum in the area where the gas flow enters the collector, and is minimal compared to the inlet area on the wall. There is a non-homogeneous space charge distribution. As particles are separated, the space charge field decreases and the aerosol collection worsens in the central area opposite the flow entrance. Therefore, the entrance area of the collector is often ineffective for particle collection.

The invention has for its object to make the deposition of electrically charged particles in the inlet region of a collector of an electrostatic emission control system more effective. Such an exhaust gas purification system for purifying aerosols loaded gases or atmospheres is known to consist of at least one assembly of an ionization and adjoining it in the flow direction collector device. The emission control system is fitted with its input to a raw gas duct or to raw gas ducts. It flows at its outlet clean gas flows into the environment or in a secondary exhaust duct.

The object of more effective particle separation is achieved by a structural structure of the emission control system according to the characterizing features of claim 1.

The ionization device of an assembly consists of at least one plane perpendicular to the channel axis with at least two identical, lying in a plane, the channel axis equally distributed ionization, through which the gas flows radially with respect to the channel axis. In the case of a gas flow through the ionization stages, either radially inward, the gas streams change their direction of flow into the associated collector device, which is centrally seated with respect to the channel axis. They are deflected into a common flow direction after the confluence with the collector, so that, in the collector region, the clear cross section in FIG Course of the gas flow with respect to the channel axis not oblique, not one-sided flow profile sets.

Or in a gas flow through the ionization stages radially outward, the collector device consists of collector stages, which in each case connects to an ionization of the ionization, in which the radial gas flow from the associated ionization stage opens and pivots in the course of gas flow parallel to the channel axis to (claim 1) ,

This is according to claim 2, an emission control system specified as follows, namely the emission control system consists of at least two, channel axially juxtaposed assemblies of one ionization and central collector device, in which the central collector devices follow each other directly and initial component of the gas continuing channel. The first upstream central collector device upstream of the gas allows the gas streams flowing into it to flow and flow only to the following central collector device. Finally, an additive, composed of currents gas stream exits from the gas collector downstream last collector device. According to claim 3, the assemblies with respect to the channel axis similar or twisted to each other.

In claim 4, on the structural basis of claim 1, the exhaust gas purification plant is specified as follows:

The emission control system now consists of at least two groups arranged axially one after the other, each comprising one ionization and collector device. The number of ionization stages per module is the same and the gas flow in the ionization stages of successive modules is radially opposite. The channel leading the raw gas with its end, closed at the end channel piece fanned either the raw gas flow through openings in its jacket wall to the attached ionization of the first device flowed into partial gas streams to one ionization in order to flow radially outwardly there to the respective attached collector stage. From this, a channel piece leads to associated ionization stage of the following module, in which the partial gas flow flows radially inward. All partial gas flows through this assembly open into the associated central collector means, redirect there and continue to flow together axially for discharging or reprocessing.

Or the channel leading the raw gas fans out at its end into channels which each open into an ionization stage of the following assembly to radially inwardly to the central collector means to stream. From there, the gas stream composed of the partial gas streams flows into the axially adjoining, end-side sealed channel piece and fanning in through openings in the jacket wall back into the attached ionization stages of the following assembly. Now they flow radially outward to the respective collector stage to continue from there to the respective or summarized discharge or reprocessing in a subsequent assembly.

Another specification based on claim 1 is described in claim 5. Thereafter, the exhaust gas purification system consists of a first gas channel cross-section-like hollow cylindrical piece as an ionization device whose wall intersects at least one plane perpendicular to the channel axis. In this sit the ionization stages through the hollow cylinder wall around the circumference uniformly distributed. They are surrounded by a second gas channel cross-section-like hollow cylinder piece like a shell over at least the length of the first hollow cylinder. In this case, either the raw gas channel opens into the first hollow cylindrical piece, which is closed on the opposite end, so that the raw gas must flow radially outwardly through the ionization stages, and the second, surrounding hollow cylindrical piece gas-tight connected by an annular disc Rohgasseitig with the first hollow cylindrical piece is. This forms the collector for the gas flowing in from the ionization stages, from where the gas stream recombined therein exits as clean gas stream on the off-gas side, open end.

Or the raw gas channel flanges on the second hollow cylinder on the front side. The second hollow cylinder is connected to the first hollow cylinder on the side facing away from the raw gas stream via a gas-tight annular disk, while the first hollow cylindrical piece is closed at the end facing the raw gas stream.

Or the raw gas channel flanges on the second hollow cylinder shell wall side and forms with the first hollow cylinder a front side gas-tight closed, annular cavity. Thus, in the frontal and shell wall side inflow of the raw gas opens the entire Raw gas stream through the ion stages radially inward into the clear area of the first hollow cylinder. The partial flows redirect there and continue to flow as a total flow from the first hollow cylinder through the collector device. Now, the clear cross-section of the first hollow cylinder is closed gas-tight at the end facing away from the further flow. Geometrically, according to claim 6, the gas channel cross-section seen from the outside convex round or convex polygonal.

The situation is thus improved by changing the way in which a gas stream flows into the inlet area of a collector device. The improvement relates to electrostatic precipitators without collecting chamber between the charging / ionizing device and the collector device, in which the gas in the input of the collector device only through an opening in a side wall of the collector device, in which the gas flow within the collector changes direction.

To improve the space charge distribution in the inlet region of the collector device is therefore proposed to flow the gas stream with charged particles through at least two mutually opposite in a plane openings in the side wall of the collector. The distribution of the space charge can therefore also be improved by the gas flow with charged particles flowing uniformly and uniformly through a plurality of openings in the side wall of the collector housing which sit in one or more successive planes.

Inadequacies of conventional emission control systems are eliminated. Responsible is the structurally direct succession of charge / ionization stage and collector as well as with respect to the collector axis quasi symmetrical space charge distribution over the clear cross section of the inlet area at the collector. By such a structural structure of the emission control system is also a technically simple and easy to handle construction.

Figur 1a

Abscheider ohne Sammelkammer nach dem Stand der Technik;

Figur 1b

Abscheider ohne Sammelkammer nach dem Stand der Technik;

Figur 2a

Kollektoreinrichtung mit drei Gebieten im Eintrittsbereich;

Figur 2b

Raumladungsdichteverlauf bei einseitiger Einströmung;

Figur 2c

Raumladungsdichteverlauf bei beidseitiger Einströmung;

Figur 3a

Seitenansicht des Abscheiders mit zwei einander gegenüberliegenden Ionisierungsstufen;

Figur 3a

Draufsicht des Abscheiders mit zwei einander gegenüberliegenden Ionisierungsstufen

Figur 4

Draufsicht des Abscheiders mit vier einander paarweise gegenüberliegenden Ionisierungsstufen;

Figur 5a

Seitenansicht eines Abscheiders aus zwei Abscheiderebenen;

Figur 5a

Draufsicht eines Abscheiders aus zwei Abscheiderebenen;

Figur 6

Draufsicht eines Abscheiders aus zwei zueinander verdrehten Abscheiderebenen;

Figur 7a

kreiszylindrische Kollektoreinrichtung in Seitenansicht mit einem Wandabschnitt als Ionisierungseinrichtung;

Figur 7b

kreiszylindrische Kollektoreinrichtung in Draufsicht mit einem Wandabschnitt als Ionisierungseinrichtung;

Figur 8

prismatische Kollektoreinrichtung in Seitenan- und Draufsicht mit einem Wandabschnitt als Ionisierungseinrichtung;

Figur 9

Seitenansicht eines Abscheiders aus zwei Abscheiderebenen mit ebenenweise radial entgegengesetzter Gasströmung in den Ionisierungseinrichtungen

The invention will be explained in more detail below with reference to the drawing. Show it:

FIG. 1a

Separator without collecting chamber according to the prior art;

FIG. 1b

Separator without collecting chamber according to the prior art;

FIG. 2a

Collector device with three areas in the inlet area;

FIG. 2b

Space charge density profile with one-sided inflow;

Figure 2c

Space charge density profile with bilateral inflow;

FIG. 3a

Side view of the separator with two opposite ionization stages;

FIG. 3a

Top view of the separator with two opposite ionization stages

FIG. 4

Top view of the separator with four mutually opposite ionization stages;

FIG. 5a

Side view of a separator of two separator levels;

FIG. 5a

Top view of a separator from two separator levels;

FIG. 6

Top view of a separator of two mutually twisted Abscheiderebenen;

Figure 7a

circular cylindrical collector device in side view with a wall portion as ionization device;

FIG. 7b

circular cylindrical collector device in plan view with a wall portion as ionization device;

FIG. 8

prismatic collector device in side and top view with a wall portion as ionization;

FIG. 9

Side view of a separator consisting of two separator planes with plane-wise radially opposite gas flow in the ionization devices

The space charge separators, known from the prior art ( U.S. 4,072,477 Fig. 1 , and DE 10 2006 055 543 , Fign.13 and 14) are presented here as a juxtaposition in Fig. 1 presented. In the separators, the output of the charging / ionizing device is coupled to a grounded collector device constructed of electrically conductive packing material, for example tower packing elements. The gas flow changes its flow direction in the input region of the collector device. In FIG. 2a If the gas stream enters the inlet area of the collector device only from the one left-hand opening in the picture, it is roughly and divided by two parallel vertical lines into the areas following one another in the entrance area over the clear width: entrance, central and opposite. The space charge density decreases there in the axial extension of the opening axis to the opposite wall of the collector device from. FIG. 2b shows the course of the decrease of the space charge or the space charge density curve qualitatively with one-sided inflow from the ionization stage: the space charge density is initially maximum in the entrance area, decreases rapidly towards the center and is minimal on the opposite wall. The course of the space charge density decreases from the inflow opening to the opposite wall, ie over the clear diameter there, monotonously or obliquely. In such a structural arrangement, the entrance area of the collector means is used inefficiently for particle deposition / collection.

Due to the inflow of the gas stream with charged particles through the wall of the collector device into the inlet region from opposite directions through at least two opposing openings, the space charge distribution is significantly improved there, because two space charge density profiles overlap oppositely. This result is qualitative in Figure 2c represented over the clear diameter of the inlet region of the collector device. There is no space-poor area on the opposite wall more. At most there is a depression of the central Space charge distribution or space charge density profile. Two inflow openings must be present at least.

The loaded with charged particles / aerosols gas penetrates via opposing openings in the collector. Therefore, more charged particles penetrate into the central entrance area, where they increase the space charge density. This increases the deposition efficiency and makes more intensive use of the entry area for particle collection. When gas flows from opposite directions / openings mix in the central area, the turbulence increases the space charge distribution and thus the collector efficiency.

The separator, in which the gas stream with charged particles / aerosols from at least two mutually opposite openings in the side walls enters the inlet region of the collector 3, is schematically shown in FIGS FIGS. 3a ) in the side view and in FIG. 3b ) shown in plan view. The separator includes the charging / ionizing device consisting of these, for example, two channels / ionization stages 1 and 2. The direction of gas flow is indicated by arrow.

The charging / ionizing device can consist of two but also more than two channels / ionization stages. An even number of ionization stages is preferable because then, with equal distribution about the axis of the separator, there are always two openings of ionization stages in the entry region axially facing each other and the space charge densities in the two successive gas flows over the clear cross section of the collector entry region as desired , hump-shaped superimpose, provided that the inflows are equally strong. With 3 or more odd-numbered, high-flow inflows into the collector inlet area, an asymmetrical space charge density distribution over the clear cross-section with increasing number of inflows is always weaker, ie becomes more symmetrical. Unequal strong Inflows into the inlet region result in an asymmetry of the space charge profile over the clear cross section with respect to the separator axis, which is dependent on the inflow intensities.

FIG. 4 shows the structure of a separator, in which the four ionization stages 1, 2, 4, 5 of the ionization lie in a plane perpendicular to the axis of the separator, evenly distributed sit around this axis and always two such ionization stages 1, 2 and 4, 5 with their inlet opening in the central collector means 3 are opposite, that is, the respective two gas flows from the ionization stages 1 and 2 and 4 and 5 are directed towards each other or the axes of these inlet openings coincide in pairs. The respective gas flow through the ionization stages 1, 2, 4, 5 flows radially to the axis of the separator, as indicated by the arrows.

If the ionization device consists of at least four ionization stages, these can be distributed on at least two levels arranged one after the other in a deposition-axial manner. Seen in Abscheideraxialer direction, congruent or rotated by an angle α against each other, if the planes are identical. Otherwise, the uniform distribution of the ionization stages around the separator axis applies, so that the required space charge density distribution in the entry region of the central collector device is more easily achieved. FIGS. 5a and 5b show a congruent two-level construction of the separator with each radially inwardly directed to the separator axis flow through the ionization stages 1, 2 and 4, 5 (claim 3). The two central collector devices are built together, they follow one another continuously and therefore form the entire central collector means 3. The two inflows per plane are directed towards each other at the exit from the respective ionization stage, bend upwards and flow as a gas flow from this plane in the Collector device further to unite with the gas flow of the following level to the entire gas stream from the separator. FIG. 5a shows the side view of the separator assembly with the respective indicated High voltage connection HV per ionization stage. FIG. 5b shows the top view and the view in Abscheideraxialer direction. FIG. 6 shows, for example, the rotation of the two identical planes of the ionization device, which are rotated around the Abscheiderachse by the angle α, which is pointed here, against each other. A rotation of successive levels of the ionization device of 0 <= α <= 90 ° can be realized (claim 3).

A construction of the space charge separator such that the ionization device with its inflow openings in the collector device form part of the same is in a convex round, here especially circular cylindrical design in the FIGS. 7a and 7b shown. The gas stream enters the charging / ionizing device 7 through the shell wall side flange 9 for the raw gas channel in the comprehensive annular channel 6 and radially inwardly through the ionizing 8 therethrough. The ionizing nozzles 8 are located in several parallel successive planes in the circular hollow cylinder wall, or the ionizing device 7 is formed here. The plane-wise radial inflow therefrom into the central collector device causes per plane the distribution of the space charge density over the clear cross-section of the inlet region and is rotationally symmetrical with at least planar flow equality from the ionizing nozzles 8 to the separator axis. Thus, there is no charge-dead distribution regions of the space charge in this entry region and thus an extensive equal attraction of the grounded inner wall of the collector device to the charged particles / aerosols from the passing gas stream, whereby the particles / aerosols impinging on the grounded wall are electrically neutralized, with flushing liquid running down thereupon entrained and emanated from the separator.

The hollow cylindrical wall section with the ionizing nozzles 8 in the inlet region of the collector device with a circular light cross section (claim 6) can be used as a circular curved, grounded nozzle plate, as shown in DE 10 2006 055 543 , ( DE 10 2005 4045 010 and DE 10 2005 023 521 and DE 102 44 051 Be known, to be directly to the central collector device in the flow direction frontally, here in the picture above the Figure 7a , is grown. FIGS. 8a and 8b show a convex polygonal, specially quadrangular construction of the separator (claim 6) in the way as the convex round, specially circular separator according to FIGS. 7a and 7b , Its ionization device consists of four flat nozzle plates approximately according to DE 10 2006 055 0543 , which form a rectangular clear cross-section. Rohgaseinströmung and clean gas outflow are as in Figure 7a displayed. Here, too, several levels of ionization stages are strung together in a separator-like manner.

To force the gas flow of the separator is at one end by a plate as in the structure of the FIGS. 7a and 8a closed, this is indicated by the thick line in the picture below.

FIG. 9 illustrates how the embodiment according to claim 4 can be realized by way of example. The raw gas shown in the picture (arrow) enters vertically centrally into the separator, the channel leading to the raw gas, he is not shown flanges with its tail on the end face closed in channel piece 11, from which the raw gas flow to the left and on the right in the picture, that is under direction change, in the respective charge / ionization stage 1 and 2 divides, preferably evenly. Both partial gas streams flow through their ionization stage 1, 2 with respect to the Abscheiderachse radially outward, in which in each case the ionization of the particles / aerosols via high voltage HV. From the two ionization stages 1 and 2, the gas streams enter the outside, directly mounted collector 10, the outer collector 10, and are forcibly deflected upward in the image. In extension downwards flanges a front side down closed pipe section, which is closed at its lowest point and there has a discharge device, see indicated small flange. At the output of both outer collectors 11 flanges each again an end face in extension closed pipe section, the flanged wall side flanks to the associated ionization. The initially vertically upwardly flowing partial gas flow thus enters with deflection into the following ionization stage 4 or 5 and flows therein radially inwardly towards the separator axis. In these two ionization stages 4 and 5, an ionization of the remaining, electrically neutral particles / aerosols in the respective partial gas flow over high voltage HV is given. The partial gas streams emerge from the opening of their respective ionization stage 4, 5 and into the inlet region of the jacket wall-side flanged central collector device 3. In this inlet region, the two partial gas streams meet again, pivot in the same direction, in the image upwards as a recombined gas stream, and finally emerge from the central collector device 3 as clean gas flow. In the inlet region of the central collector 3, the non-oblique, possibly two-humped, preferably symmetrical to the separator axis space charge distribution is again achieved, which causes the effective deposition of particles / aerosols at the collector.

The high efficiency of particle separation in such a structured separator is summarized below in the process inside the electrostatic space charge separator:

The gas flow with particles / aerosols passes through the charging / ionizing device, which is not presented in detail here in writing or in the drawing. For example, she is from the DE 10 2006 055 546 refer to. The particles in the gas stream are electrically charged in the field of a corona discharge. In the electrostatic "single-field" separator, the aerosol-laden gas stream passes through the ionization stages 1 and 2 or 1, 2, 4, 5, depending on the construction of the separator into the inlet region of the collector device 3.

Since, when entering the collector device, viewed over the clear cross-section, there is no longer a one-sided space charge density distribution decreasing towards the opposite wall, a much more effective collection of the electrically charged ones occurs in the collector Particles. This advantageous over the clear cross-section, preferably symmetrical to the separator axis, so no longer unilaterally decreasing distribution of space charge leads to the much more effective deposition, which comes about only by the counterflow and rectified deflection of two partial gas streams.

For the construction of the collector reference is made to the state of the art, for example DE 102 59 410 , in which a spray system for washing is presented.

The advantage of the separator according to the invention is the process-supporting use of the inlet region of the collector device. As a result, the size of the collector device can be significantly reduced and the collector housing can be made smaller. Thus, a compact design of the separator is given, in particular, this jumps to the exemplary embodiment according to the FIGS. 7a to 8b out. This leads to the cost reduction for the construction of the space charge separator and thus investment costs.

List of reference numerals only for FIGS. 2a to 9:

1

ionization

2

ionization

3

collector device

4

ionization

5

ionization

6

annular channel

7

Ionization / n

8th

jet

9

flange

10

Collector, outdoor collector

11

channel piece

Claims (6)

1. Physical structure of flue gas cleaning systems for cleaning aerosol-laden gases or atmospheres,
   consisting of at least one assembly of an ionization device and collector device following it in the direction of flow,
   with the flue gas cleaning system being attached by its inlet to a raw gas duct or raw gas ducts and at whose outlet scrubbed gas flows into the environment or enters an attached duct,
   characterised in that
   the ionization device of an assembly comprises at least one level at right angles to the centreline of the duct having at least two identical ionization stages lying in a plane and uniformly distributed about the centreline of the duct, through which the gas flows radially relative to the centreline of the duct,
   when gas flows through the ionization stages radially inwards, the gas streams enter the associated collector device which sits centrally relative to the centreline of the duct and are all identically deflected there, such that, in the course of the gas flow, a flow profile which is not at an angle to the centreline of the duct forms in the collector region across the unobstructed cross-section, or
   when gas flows through the ionization stages radially outwards, the collector device consists of collector stages each of which follows an ionization stage of the ionization device in which the radial gas stream enters from the associated ionization stage and in the course of the gas flow is deflected parallel to the centreline of the duct.
2. A flue gas cleaning system having a physical structure according to claim 1, characterised in that the flue gas cleaning system consists of at least two assemblies in line adjacent to one another on the centreline of the duct, each comprising an ionization device and a central collector device, the central collector devices follow on one another immediately and are an initial constituent of the duct carrying the gas, wherein the central collector device which comes first in the direction of gas flow only allows the gas streams entering it to flow on and through to the next central collector device so that a cumulative gas stream exits the collector device which comes last in the direction of gas flow.
3. A flue gas cleaning system according to claim 2, characterised in that the assemblies are strung together either the same way relative to the centreline of the duct or skewed relative to one another.
4. A flue gas cleaning system having a physical structure according to claim 1, characterised in that the flue gas cleaning system consists of at least two assemblies in line adjacent to one another on the centreline of the duct, each assembly comprising an ionization and a collector device, with the number of ionization stages being the same in each assembly and the gas flow in the ionization stages of successive assemblies being radially opposed, wherein
   either the raw-gas-carrying duct with its end-blanked terminating section divides up the raw gas stream through openings in its jacket wall with the attached ionization device of the first assembly facing the flow into partial gas streams, each to one ionization stage, to then flow radially outwards to the respectively attached collector stage from where a section of duct leads to the associated ionization stage of the subsequent assembly in which the partial gas stream flows radially inwards, and all partial gas streams through this assembly open into the associated central collector device where they are deflected and flow axially together onward to the discharge or further processing, or the raw-gas-carrying duct divides at its end into channels each of which opens out into one ionization stage of the subsequent assembly to then flow radially inwards to the central collector device from where the gas stream that is made up of the partial gas streams flows into the axially adjoining, end-blanked section of duct where it again divides up through openings in the jacket wall into the attached ionization stages of the subsequent assembly to now flow radially outwards to their respective collector stage and from there to flow onward to their respective or combined discharge or to further processing in a subsequent assembly.
5. A flue gas cleaning system having a physical structure according to claim 1, characterised in that the flue gas cleaning system consists of a first hollow-cylinder section similar to the cross-section of the gas duct as an ionization device whose wall intersects at least one level perpendicular to the centreline of the duct and in which sit the ionization stages uniformly distributed about the periphery by the hollow cylinder wall, and is enclosed jacket-like by a second hollow-cylinder section similar to the cross-section of the gas duct over at least the length of the first hollow cylinder, either the raw gas duct opens out into the first hollow-cylinder section - which is blanked at its opposite end-face - in such a way that the raw gas is forced to flow radially outwards through the ionization stages, and the second enclosing hollow-cylinder section is connected gas-tight to the first hollow-cylinder section by a disk plate on the raw gas side, forming the collector for the gas inflowing from the ionization stages, from where the recombined gas stream exits as a scrubbed gas stream from the open end-face on the side facing away from the raw gas,
   or the raw gas duct is flange-mounted to the second hollow cylinder, the second hollow cylinder is connected to the first hollow cylinder on the side facing away from the raw gas stream by a gas-tight disk plate, the first hollow-cylinder section being blanked at the end facing towards the raw gas stream,
   or the raw gas duct is flange-mounted to the second hollow cylinder at the jacket-wall end and with the first hollow cylinder forms an annular space that is blanked gas-tight at the end face so that upon the inflow of raw gas on the end-face side and jacket-wall side the entire raw gas stream flows radially inwards through the ion stages [sic] into the unobstructed region of the first hollow cylinder where the partial streams are deflected and flow as a combined stream out of the first hollow cylinder and on through the collector device, the clear cross-section of the first hollow cylinder being blanked gas-tight at the end facing away from the onward flow.
6. A flue gas cleaning system according to claim 5, characterised in that the gas duct cross-section is convexly round or convexly polygonal when seen from the outside.

Images