CH710382B1 - Process for exhaust aftertreatment. - Google Patents

Abstract

A method for exhaust aftertreatment of an internal combustion engine (10) exiting exhaust (11), wherein the exhaust gas (11) is guided over a rotary particle filter (12) such that a part of the filter medium is flowed through by the exhaust gas (11), and that a part or section of the filter medium which is rotated out of the exhaust gas flow is not passed through by the exhaust gas, wherein the part or section of the filter medium rotated out of the exhaust gas flow inside the rotary particle filter (12) is initially located in a first sub-chamber (14) outside the exhaust gas flow. the rotary particle filter (12) is regenerated with oxidation of soot in the filter medium, that subsequent to this regeneration in a second outside of the exhaust gas flow sub-chamber (15) of the rotary particle filter (12) is removed from the out of the exhaust flow portion or portion of the filter medium ash; and that subsequently to the Re generation and ash removal turned out of the exhaust stream portion or portion of the filter medium is screwed into the exhaust stream.

Description

Description: The invention relates to a method for exhaust gas aftertreatment.

From practice, methods for exhaust aftertreatment of the exhaust gas of internal combustion engines are known, which use a particulate filter and at least one upstream of the particulate filter arranged in the flow direction of the exhaust gas aftertreatment assembly. The term "particle filter" should be understood as meaning both conventional particle filters which have a filter medium through which the exhaust gas flows, and particle separators in which the exhaust gas flows around a filter medium serving as a separation structure.

When viewed in the flow direction of the exhaust gas upstream of the particulate filter positioned exhaust aftertreatment assembly is in particular an oxidation catalyst for the oxidation of nitrogen monoxide (NO) in nitrogen dioxide (NO2).

Then, when viewed in the flow direction of the exhaust gas stream upstream of the particulate filter, an oxidation catalyst for the oxidation of NO is positioned in NO2, oxidized in the oxidation catalyst NO using the residual oxygen contained in the exhaust stream O2 to NO2 according to the following equation:

In this oxidation of nitrogen monoxide to nitrogen dioxide is at high temperatures, the equilibrium of the oxidation reaction on the side of nitrogen monoxide. This has the consequence that at high temperatures, the recoverable amount of nitrogen dioxide is severely limited.

In the particulate filter, the nitrogen dioxide obtained in the oxidation catalyst is reacted with carbonaceous particles collecting in the particulate filter, so-called soot, to carbon monoxide (CO), carbon dioxide (CO2), nitrogen (N2) and nitrogen monoxide (NO). In this case, in the sense of a passive regeneration of the particulate filter, a continuous removal of the carbon-containing particulate matter or of the carbon black deposited in the particulate filter takes place, this conversion taking place according to the following equations:

Then, if with such a passive regeneration of the particulate filter can not be a complete conversion of embedded in the particulate filter, carbonaceous particulate matter or soot, the carbon content or soot content in the particulate filter increases, with a particulate filter with a flow of exhaust gas through the filter medium then Constipation tends, which ultimately increases a so-called exhaust back pressure on an upstream of the exhaust aftertreatment system internal combustion engine. An increasing exhaust back pressure on the internal combustion engine reduces the performance of the internal combustion engine and causes increased fuel consumption. In order to avoid an increase in the carbon-containing fines particles or the soot in the particle filter, it is already known from practice to provide the exhaust gas flowed through filter medium of a particle filter with a catalytic coating. In this case, platinum-containing coatings are preferably used. However, the use of such particle filters with catalytic coating can prevent the charge of the particulate filter with carbonaceous particulate matter, ie soot, only to an insufficient extent.

Furthermore, it is known from practice to reduce the loading of a flow-through of the filter medium of a particulate filter with soot, to use an active regeneration of the filter medium. In such an active regeneration, the exhaust gas temperature is actively raised in order to burn off carbon-containing fines particles or soot particles which have accumulated in the filter medium via an exothermic reaction or oxidation of the hydrocarbons. The burning off of the carbon with the help of oxygen in a particle filter takes place according to the following equation:

In an active regeneration by burning off the soot particles, a strong rise in temperature up to 1000 ° C can form in the particulate filter. With such a strong increase in temperature can lead to damage of the particulate filter.

From US 5 013 340 a method for the exhaust aftertreatment of an internal combustion engine exiting exhaust gas using a rotary particle filter is known, wherein an in the exhaust gas flowed-in part or portion of the filter medium of the rotary particle filter is flowed through by exhaust gas, and wherein a from the exhaust stream rotated part or section of the filter medium of the rotary particle filter is not flowed through by the exhaust gas, but for cleaning the filter medium of compressed air.

On this basis, the present invention has the object to provide a novel method for exhaust aftertreatment.

This object is achieved according to a first aspect by a method for exhaust aftertreatment according to claim 1.

According to the first aspect of the invention, a turned-off from the exhaust stream portion or portion of the filter medium, while the twisted into the exhaust stream part or portion of the filter medium is flowed through by exhaust gas within the rotary particle filter initially in a first outside of the exhaust gas flow sub-chamber of the Rotationspartikelfilters regenerated under oxidation of soot in the filter medium, which is then removed to this regeneration in a second outside of the exhaust gas flow sub-chamber of the rotary particle filter from the respective out of the exhaust stream twisted portion or portion of the filter medium ash, and wherein subsequent to the regeneration and ash removal of the respective rotated out of the exhaust stream part or portion of the filter medium is screwed into the exhaust stream.

With the first aspect of the present invention, it is proposed for the first time, in a rotary particle filter parallel to the exhaust gas purification using the rotated in the exhaust stream portion or portion of the filter medium, the rotated out of the exhaust stream portion or portion of the filter medium regeneration by oxidation of soot and then subjected to an ash removal. The regeneration of the rotated out of the exhaust stream portion or portion of the filter medium by oxidation takes place in a first outside of the exhaust gas flow sub-chamber of the rotary particle filter, wherein the ash removal takes place in a second, located outside the exhaust flow sub-chamber of the rotary particle filter.

Accordingly, at least three sub-chambers of the rotary particle filter are used in parallel, namely a partial chamber of the rotary particle filter for exhaust gas purification located in the exhaust gas flow and two sub-chambers of the rotary particle filter for regeneration and ash removal located outside the exhaust gas flow. Accordingly, in parallel to the exhaust gas purification, the filter medium of the rotary particle filter is regenerated in sections or sections and freed from ash. This allows a particularly advantageous exhaust aftertreatment.

According to an advantageous embodiment of the first aspect of the invention, the rotated out of the exhaust stream portion or portion of the filter medium is then heated to the regeneration and ash removal and before screwing into the exhaust stream in a third outside the exhaust gas flow sub-chamber of the rotary particle filter to a to compensate for the ash removal adjusting temperature drop of the filter medium.

With this advantageous development can be avoided that, as a result of adjusting itself in the ash removal temperature drop of the filter medium, when the corresponding part or portion of the filter medium is again flowed through by exhaust gas, an exhaust gas temperature drop forms, which the effectiveness of exhaust aftertreatment in downstream of the rotary particle filter exhaust aftertreatment assemblies, such as in catalysts affected.

According to a further advantageous embodiment of the first aspect of the invention, a screwed into the exhaust stream portion or portion of the filter medium is rotated out of the exhaust stream for regeneration and screwed into the first outside of the exhaust flow sub-chamber of the rotary particle filter, followed by the regeneration for ash removal this section or part of the filter medium out of the first out of the exhaust flow part chamber of the rotary particle filter and rotated into the second outside of the exhaust gas flow sub-chamber of the rotary particle filter, the flow side of the first outside of the exhaust gas flow sub-chamber is separated, is rotated, and then turned off at the ash removal of this section or part of the filter medium from the second outside of the exhaust gas flow sub-chamber of the rotary particle filter and either direktba r or indirectly via the third outside of the exhaust gas flow sub-chamber of the rotary particle filter, which is on the flow side of the second outside of the exhaust gas flow subchamber of the same separated, is screwed into the exhaust gas flow. As a result, the filter medium of the rotary particle filter can be subjected to regeneration and ash removal by oxidation of soot in a particularly advantageous manner.

According to a further advantageous embodiment of the first aspect of the invention, the regeneration is carried out as active regeneration by heating the untwisted from the exhaust stream portion or portion of the filter medium, wherein for heating the actively regenerated part or portion of the filter medium the same in the first outside The exhaust gas flow lying sub-chamber is flowed through by heated air. Preferably, with a sensor positioned downstream of the rotary particle filter, the oxygen content downstream of the rotary particle filter and optionally with a sensor positioned upstream of the rotary particle filter is measured upstream of the rotary particle filter based on the oxygen content measured by the or each sensor, loading of the rotary particle filter with soot and / or or determining a temperature increase of the rotary particle filter as a result of the regeneration and / or a rate of regeneration, and wherein the active regeneration is controlled based on the oxygen content measured by the or each sensor. As a result, the active regeneration in the rotary particle filter can be realized particularly advantageously, namely a

Control of active regeneration while avoiding high temperatures and thus a risk of damage to the rotary particle filter.

According to a second aspect, this object is achieved by a method for exhaust aftertreatment according to claim 8.

According to the second aspect, an exhaust gas leaving the exhaust engine is guided over a rotary particle filter, that in the exhaust gas flowed part or portion of the filter medium is flowed around by the exhaust gas, and not rotated from the exhaust stream portion or portion of the filter medium is not flowed around by the exhaust gas in which the part or section of the filter medium turned out of the exhaust gas flow is removed from a sub-chamber of the rotary particle filter outside the exhaust gas flow and freed from soot and ash outside the rotary particle filter, then returned to the sub-chamber of the rotary particle filter which is outside the exhaust gas flow and returned to the exhaust gas flow is screwed into it. According to the second aspect of the invention, it is proposed for the first time to use filter medium flowed around exhaust gas in a rotary particle filter, which is then removed from the rotary particle filter when it has been removed from the exhaust gas stream in order to free the filter medium from soot and ash outside the rotary particle filter. Again, a particularly effective treatment is possible.

According to an advantageous development of the first aspect and the second aspect of the invention, it is possible to treat in parallel to the treatment of the rotated out of the exhaust stream portion or portion of the filter medium and the rotated into the exhaust stream portion or portion of the filter medium, so to to remove the part or section of the filter medium, which has been screwed into the exhaust gas stream, within the rotary particle filter in the sense of regenerating soot. For this purpose, preferably in an upstream of the rotary particle filter arranged oxidation catalyst SO2 is oxidized in SO3, wherein the SO3 and / or precipitated H2SO4 of the oxidation of soot in the rotary particle filter on the screwed into the exhaust stream portion or portion of the filter medium, and wherein in the oxidation catalyst as an active component for oxidation of SO 2 in SO 3 at least vanadium in a proportion of more than 5%, preferably more than 7%, more preferably more than 9%, and preferably additionally potassium and / or sodium and / or iron and / or cerium and / or cesium and / or oxides of these elements is used, being used in the oxidation catalyst as the base material titanium oxide and / or silica preferably stabilized by tungsten oxide. To the SO 2 oxidation catalyst, a NO oxidation catalyst may be connected in parallel.

Preferred embodiments of the invention will become apparent from the dependent claims and the description below. Embodiments of the invention will be described, without being limited thereto, with reference to the drawing. Showing:

1 shows a block diagram for clarifying a first variant of the inventive method for exhaust aftertreatment according to the first aspect of the invention;

FIG. 2 shows a cross section through the rotary particle filter of FIG. 1; FIG.

3 shows a block diagram for clarifying a second variant of the method according to the invention for exhaust aftertreatment according to the first aspect of the invention;

4 shows a cross section through the rotary particle filter of FIG. 3;

5 shows a block diagram for clarifying a first variant of the method according to the invention for the exhaust gas aftertreatment according to the second aspect of the invention;

FIG. 6 shows a cross section through the rotary particle filter of FIG. 5; FIG.

7 shows a block diagram for clarifying a second variant of the method according to the invention for exhaust aftertreatment according to the second aspect of the invention; and

8 shows a block diagram to illustrate a third variant of the method according to the invention for the exhaust gas aftertreatment according to the second aspect of the invention.

The invention relates to a method for exhaust aftertreatment of exhaust gas leaving an internal combustion engine. In particular, the invention is used in operated with excess air large internal combustion engines, such as in marine diesel engine.

With reference to FIGS. 1 and 2, a method according to the invention for the exhaust gas aftertreatment of exhaust gas 11 leaving an internal combustion engine 10 according to a first aspect of the invention will now be described. 1 shows an internal combustion engine 10, the exhaust gas 11 leaving the internal combustion engine 11 being guided via a rotary particle filter 12 for exhaust gas aftertreatment.

The rotary particle filter 12 comprises a filter medium, which is flowed through by exhaust gas. In this case, a first portion or a first part of the filter medium is screwed into the exhaust gas stream and is flowed through by exhaust gas, wherein a second part or a second portion of the filter medium is rotated out of the exhaust gas and is not flowed through by exhaust gas.

The exhaust gas flowed through and thus turned into the exhaust gas flow portion or part of the filter medium is positioned in a sub-chamber 13 of the rotary particle filter 12, which is flowed through by exhaust gas.

The rotated out of the exhaust stream portion or portion of the filter medium is first regenerated within the rotary particle filter 12 in a first outside of the exhaust gas flow sub-chamber 14 of the rotary particle filter 12 with oxidation of soot in the filter medium, followed by this regeneration of the filter medium this from the exhaust stream removed part or portion of the filter medium in a second outside of the exhaust gas flow sub-chamber 15 of the rotary particle filter 12 is removed from ash by ash is removed from this part or portion of the filter medium.

Subsequent to the regeneration of this part or portion of the filter medium in the first sub-chamber 14 and the ash removal from this part or portion of the filter medium in the second sub-chamber 15, this part or portion of the filter medium can then be screwed back into the exhaust stream. The rotational movement of the filter medium is visualized in Fig. 2 by an arrow 16.

The exhaust gas aftertreatment process described with reference to FIGS. 1 and 2 therefore uses at least three subchambers of the rotary particle filter 12, namely a subchamber 13 located in the exhaust gas flow and the two subchambers 14 and 15 located outside the exhaust gas flow, the filter medium passing through Turning the same in the direction of the arrow 16 in sections or sections of the sub-chamber 13 in the sub-chamber 14, from the sub-chamber 14 in the sub-chamber 15 and subsequently from the sub-chamber 15 back into the sub-chamber 13 can be moved to parallel to the exhaust aftertreatment in the Partial chamber 13 to make the regeneration in the partial chamber 14 and the ash removal in the sub-chamber 15 serially.

The sectioned or partial regeneration of the exhaust gas stream herausgedrehten filter medium in the sub-chamber 14 of the rotary particle filter 12 is preferably carried out as active regeneration and heating of the rotated out of the exhaust stream portion or portion of the filter medium, including heating the active part to be regenerated or Section of the filter medium of the same in the out of the exhaust gas flow sub-chamber 14 of the rotary particle filter 12 is flowed through by heated air 17, which can be heated, for example by means of a heater, not shown, to a defined temperature, so as to actively regenerate part or portion of the filter medium for active regeneration to a defined process temperature.

Following the preferably active regeneration of a rotated out of the exhaust stream portion or portion of the filter medium in the sub-chamber 14 of the rotary particle filter 12, the regenerated part or portion of the filter medium after transferring it into the sub-chamber 15 of the rotary particle filter 12 in the sub-chamber 15 a Ash removal is performed by removing ash from the previously regenerated part or portion of the filter medium, so that this part or portion of the filter medium is preferably flowed through by a solvent 18.

This solvent 18 may be, for example, water or sulfuric acid.

If sulphate-containing ash deposits are to be removed from the filter medium of the rotary particle filter 12, a sodium carbonate-containing solution may be passed as the solvent through the part or section of the filter medium which is located in the partial chamber 15 of the rotary particle filter 12. This forms water-soluble sodium sulfate, which can be washed out. The possibly forming carbonates from the ash constituents are water-soluble and can be brought into solution and washed out with the aid of an acid, for example with the aid of CaSO 4, for example. The reaction product CaCl 2 is readily soluble in water and can easily be washed out of the filter medium with water. As an example for CaSO4, this is done as follows:

According to the first aspect of the invention, a rotary particle filter is used for exhaust aftertreatment, which has at least three sub-chambers, wherein a first sub-chamber 13 of the rotary particle filter 12 or in this first sub-chamber 13 screwed filter medium is flowed through by exhaust gas, and one from this sub-chamber 13 and therefore rotated out of the exhaust gas flow part or portion of the filter medium in a first outside the exhaust gas flow sub-chamber 14 is subjected to regeneration by oxidation of soot and subsequently in a further outside of the exhaust gas flow sub-chamber 15 of an ash removal.

In the exhaust gas flowed-in filter medium is therefore turned out for regeneration from the exhaust stream and thus the sub-chamber 13 and first into the first out of the exhaust flow compartment chamber 14 of the particulate filter 12 is rotated to be regenerated in this sub-chamber 14, wherein subsequently to the Regeneration in the sub-chamber 14 of the rotary particle filter 12 located outside the exhaust-gas flow, the corresponding part or section of the filter medium from the first sub-chamber 14 lying outside the exhaust-gas flow

is rotated out of the rotary particle filter 12 and into the second outside of the exhaust gas flow sub-chamber 15 of the rotary particle filter is rotated to make in this sub-chamber 15, which is separated from the flow side of the sub-chamber 14, the ash removal.

Advantageous developments of the method described with reference to FIGS. 1 and 2 for exhaust aftertreatment according to the first aspect of the invention will be described below with reference to FIGS. 3 and 4, wherein in Figs. 3 and 4 for the same components same Reference numerals are used as in Figs. 1 and 2. Therefore, reference is made to avoid unnecessary repetition with respect to these in Figs. 3 and 4 identical assemblies to the relevant embodiments of FIGS. 1 and 2.

A first difference of Fig. 3 and 4 compared to Figs. 1 and 2 is that in Figs. 3 and 4, the rotary particle filter 12 adjacent to the two outside of the exhaust gas flow sub-chambers 14 and 15 another outside the Exhaust gas flow lying sub-chamber 19 includes, wherein that portion or part of the filter medium, which is located in this third outside the exhaust gas flow sub-chamber 19, following the ash removal and before screwing into the exhaust gas flow through the sub-chamber 13 and therefore before screwing in the exhaust gas flow is heated within the sub-chamber 19 in order to compensate for a drop in temperature of the filter medium occurring during the ash removal. This is accomplished in Fig. 3, characterized in that the heated air 17, which is guided for active regeneration in the first outside of the exhaust gas flow sub-chamber 14 of the particulate filter 12 via the filter medium located in the same, returned and then via the sub-chamber 19 and the is guided in the sub-chamber 19 located filter medium to heat the same. In this way it can be avoided that, when a filter medium subjected to regeneration and ash removal is subsequently turned into the exhaust gas flow, the exhaust gas is cooled at the same, which can ensure that possibly further exhaust aftertreatment assemblies positioned downstream of the rotary particle filter 12 operate at an optimum process temperature of the exhaust gas can be.

A further difference of the embodiment of FIGS. 3 and 4 with respect to the embodiment of FIGS. 1 and 2 is that in FIGS. 3 and 4 both upstream of the rotary particle filter 12 and downstream of each of the same sensor 20 and 21st is present, with the aid of which upstream and downstream of the rotary particle filter 12, namely upstream and downstream of the first out of the exhaust gas flow sub-chamber 14 of the rotary particle filter 12, the oxygen content in the guided for active regeneration via the first sub-chamber 14 air can be measured.

On the basis of the oxygen content detected by the sensors 20, 21, a loading of the respective part or portion of the filter medium of the rotary particle filter 12 to be regenerated with soot before regeneration and / or a temperature increase due to the regeneration and / or a regeneration rate can be determined in order, for example, when a too high temperature rise due to the regeneration is detected, to regulate the active regeneration, in particular by influencing the heating device which serves to heat the air used for active regeneration.

From the oxygen content downstream of the rotary particle filter 12, which is measured by the sensor 21, and additionally from the oxygen content upstream of the rotary particle filter 12, which is detected by the sensor 20, the amount of soot burned can be determined according to the following equation:

Here, each burned oxygen molecule corresponds to a carbon molecule. By integration over time, the loading of the respective part or section of the filter medium of the rotary particle filter 12 to be regenerated with soot can be determined prior to the soot combustion.

The temperature increase due to Rußabbrands can be determined according to the following equation:

where ΔΤ corresponds to the temperature increase due to Rußabbrands, mc corresponds to the load of each part or section of the filter medium to be regenerated with soot before Rußabbrand, Huc corresponds to the calorific value of soot, At the duration of Rußabbrands, d / dt (m) the air mass flow corresponds, and α corresponds to the heat capacity of the air.

Upstream of the rotary particle filter 12, an oxidation catalyst (not shown) for oxidizing NO may be positioned in NO 2 to provide the portion or portion of the passive regeneration filter medium NO 2 contained in the sub-chamber 13 and thus in the exhaust gas flow. In this case, the NO 2 fraction relative to the total NO x fraction is preferably set such that the NO 2 fraction in the total NO x fraction is more than 10%, preferably more than 20%, particularly preferably more than 50%, to ensure an optimal passive regeneration of the filter medium within the sub-chamber 13 and use of NO2. The desired NO2 proportion of the total NOx content can

be adjusted by the NO oxidation catalyst, possibly supported by a lowering of the combustion temperature in the internal combustion engine.

In the embodiment of FIGS. 3 and 4, an oxidation catalyst 22 for the oxidation of SO 2 in SO 3 is positioned upstream of the rotary particle filter 12, wherein the SO 2 generated in the oxidation catalyst 22 and / or precipitating H 2 SO 4 can be utilized in the filter medium through which exhaust gas flows Within the sub-chamber 13 of the rotary particle filter 12 to oxidize soot.

As an active component for the oxidation of SO 2 in SO 3, at least vanadium in a proportion of more than 5%, preferably more than 7%, more preferably more than 9%, is used in the oxidation catalyst 22, wherein as additional active components for the oxidation of SO2 in SO3, where appropriate, potassium and / or sodium and / or iron and / or cerium and / or cesium and / or oxides of these elements can be used. In the oxidation catalyst 22, titanium oxide or silicon oxide, preferably stabilized by tungsten oxide, is used as base material in order to oxidise SO 2 in SO 3.

Then, if an oxidation catalyst 22 for the oxidation of SO 2 in SO 3 is present upstream of the rotary particle filter 12, a mass ratio between SO 3 and carbon black of at least 7: 1, preferably of at least 12: 1, is particularly preferred in the region of the rotary particle filter 12 of at least 16: 1.

In the embodiments of FIGS. 1 to 4, the flow directions of the sub-chambers 13 to 15, 19 are preferably all in the same direction or identical, ie not in opposite directions. This can be taken from FIGS. 1 and 3 by the orientation of the arrows representing a flow direction of exhaust gas, air and solvent.

An embodiment of an inventive method according to a second aspect of the present invention will be described below with reference to FIGS. 5 and 6, wherein in Fig. 5, an internal combustion engine 30 is shown, the exhaust gas 31 is passed through a rotary particle filter 32 for exhaust aftertreatment , The rotary particle filter 32 takes on a filter medium, which, in contrast to the embodiments of FIGS. 1 to 4 is not traversed by exhaust gas, but rather flows around exhaust gas. This filter medium is preferably a granulate, with soot and ash or reaction products of soot and ash being deposited on the granulate during the exhaust gas aftertreatment.

According to FIG. 6, the rotary particle filter 32 has two subchambers 33, 34, namely a subchamber 33 located in the exhaust gas flow and a subchamber 34 located outside the exhaust gas flow. The filter medium, which is located in the subchamber 33, is surrounded by exhaust gas. whereas the filter medium, which is located in the sub-chamber 34, is not flowed around by exhaust gas. The filter medium can be screwed in the direction of arrow 35 from the first sub-chamber 33 of the rotary particle filter 32 into the second sub-chamber 34 of the rotary particle filter 32 and thus rotated out of the exhaust gas flow, as well as the filter medium from the second sub-chamber 34 of the rotary particle filter 32 into the first sub-chamber 33rd transferred to the rotary particle filter 32 and are therefore screwed into the exhaust stream.

According to the second aspect of the invention, the filter medium, which is flowed around in the sub-chamber 33 of the rotary particle filter 32 of exhaust gas, when it has been displaced into the sub-chamber 34 of the rotary particle filter 32 and thus was rotated out of the exhaust gas flow, from the Partial chamber 34 of the rotary particle filter 32 removed and fed to a separator 36. The arrow 37 in FIG. 5 visualizes the removal of the filter medium or of granules from the sub-chamber 34 of the rotary particle filter 32 and the transfer of the same into the separating device 36.

In the separating device 36 is removed from the filter medium, which is preferably granules, soot and ash, in particular by a mechanical peeling process, such as with the aid of a trained as a drum peel separator 36 to subsequently purified granules in the sense of Arrow 38 again the rotary particle filter 32, namely the second part of the same chamber 34, feed and subsequently turn back in the direction of the arrow 35 in the sub-chamber 33 and thus the exhaust stream. Soot and ash particles and / or reaction products of the soot and ash particles with the granules, which were separated from the granules in the separator 36, are discharged from the separator 36 in the direction of the arrow 39.

Fig. 7 illustrates a development of the method described with reference to Figs. 5 and 6, wherein in Fig. 7 in accordance with Fig. 3 upstream of the rotary particle filter 12, an oxidation catalyst 22 for the oxidation of SO2 is positioned in SO3, the SO2 produced by the oxidation catalytic converter 22 and / or precipitated H2SO4 serves to oxidize carbon black directly in the rotary particle filter 32, ie in the filter medium which is located in the partial chamber 33 of the rotary particle filter 32 through which exhaust gas flows.

At least vanadium, preferably additionally potassium and / or sodium and / or iron and / or cerium and / or cesium and / or in turn in the oxidation catalyst 22 as an active component for the oxidation of SO 2 in SO 3

Oxides of these elements, used in the oxidation catalyst 22 as the base material titanium oxide or silicon oxide, preferably stabilized by tungsten oxide, is used.

In this case, the vanadium content is at least 5%, more preferably at least 7%, more preferably at least 9%, wherein downstream of the oxidation catalyst 22 in the region of the rotary particle filter 32, namely in the region of the sub-chamber 33 thereof, a mass ratio between SO3 and soot of at least 7: 1, preferably of at least 12: 1, more preferably of at least 16: 1, is set. In the variant of FIG. 7, therefore, oxidation of soot in the rotary particle filter 32 takes place on the one hand, namely within the partial chamber 33 through which exhaust gas flows. On the other hand, soot is removed from the filter medium outside of the rotary particle filter 32 in the separating device 36.

Fig. 8 shows a development of the method of Fig. 7, in which upstream of the rotary particle filter 32, not only the oxidation catalyst 22, which serves for the oxidation of SO 2 in SO 3, is arranged, but moreover a further oxidation catalyst 40, which the oxidation of NO in NO2 serves. These two oxidation catalysts 22, 40 are connected in parallel with each other, wherein each of the oxidation catalysts 22 and 40 can be shut off or disconnected via shut-off valves 41 of exhaust gas flow. If highly sulfur-containing fuel is used in the internal combustion engine 30, the exhaust gas flow is conducted via the oxidation catalytic converter 22 for the oxidation of SO 2 to SO 3 and the NO oxidation catalytic converter 40 is separated from the exhaust gas flow via the valves 41. As a result, the NO oxidation catalyst 40, which serves to oxidize NO to NO 2, is kept sulfur-free. If, on the other hand, a relatively weak sulfur-containing fuel is used, then the SO 2 oxidation catalytic converter 22 can be separated from the exhaust gas flow by closing the corresponding valves 41 and the exhaust gas is led via the NO oxidation catalytic converter 40 to the oxidation of NO into NO 2. The variant of FIG. 8 is particularly suitable for use in marine engines, which are operated on the one hand with highly sulfur-containing fuel and on the other hand with low-sulfur fuel.

An alternative to FIG. 8 for this purpose is to dispense with the shut-off valves 41 and to make the oxidation catalyst 40 operational after operation with highly sulfur-containing fuel in such a way that the exhaust gas temperature is raised and thus sulfur is desorbed in the oxidation catalyst 40. The variant with the shut-off valves 41 is preferred, however, since then, after operation of the internal combustion engine 1 with sulfur-containing fuel, the oxidation catalytic converter 40 is then immediately ready for use.

As granules can be used in the rotary particle filter 32 kataytisch inactive granules. Granules of cordierite, granite, corundum, aluminum oxide or metallic materials are used in particular. By deflecting the soot and ash particles in the rotary particle filter 32, the soot and ash particles are deposited by impaction and / or diffusion and / or interception on the catalytically inactive granules. Preferably, catalytically active granules are used. In this case, components of the exhaust gas may react with the granules in the rotary particle filter 32.

Then, when catalytically active granules is used, comes as a separator 36 is preferably a drum peeler used. Then, if catalytically inactive granules is used, can be used as a separator 36, a drum screen, a vibrating screen, a mill or a washing device, the water as a washing medium, for cleaning the granules.

The rotary particle filter 32 may be multi-stage. Exhaust gas to be cleaned in the rotary particle filter 32 then first flows through a first stage and then a second stage of the rotary particle filter 32. Both stages of the rotary particle filter 32 can then be designed as described above and are connected in series one behind the other. In the region of each of the stages, the granulate is rotatable out of the exhaust gas flow, can be liberated from soot and ash outside the step of the rotary particle filter 32 in a separating device 36, and then fed back to the respective step of the rotary particle filter 32.

Then, as shown in Fig. 2, the rotary particle filter 32 is made multi-stage, preferably differs in the individual stages of the rotary particle filter 32, the chemical composition of the granules and / or the size of the granules from each other.

Vanadium-containing fuel can also be used to operate the internal combustion engine 30. In this case, vanadium oxide is deposited on the surface of the granules, whereby soot and SO 2 can be oxidized in the sub-chamber 33 of the rotary particle filter 32.

The above methods can also be used in supercharged internal combustion engines. An SO 2 oxidation catalyst is then advantageously positioned upstream of a turbine of the exhaust gas turbocharger to promote the oxidation of SO 2 in SO 3 by the pressures and temperatures prevailing upstream of the turbine.

DESCRIPTION OF SYMBOLS 11 Internal combustion engine 11 Exhaust gas 12 Rotary particle filter 13 Partial chamber 14 Partial chamber 15 Partial chamber 16 Direction of rotation 17 Air 18 Solvent 19 Partial chamber 20 Sensor 21 Sensor 22 Oxidation catalyst 30 Internal combustion engine 31 Exhaust 32 Rotary particle filter 33 Partial chamber 34 Partial chamber 35 Direction of rotation 36 Separator 37 Granules 38 Granules 39 Russ / Ash 40 oxidation catalyst 41 shut-off valve

Claims (12)

claims 1. A method for exhaust aftertreatment of an internal combustion engine (10) leaving the exhaust gas (11), wherein the exhaust gas (11) via a rotary particle filter (12) is guided, that in the exhaust gas flowed-in part or portion of the filter medium flows through the exhaust gas (11) is, and that a rotated out of the exhaust stream portion or portion of the filter medium is not flowed through by the exhaust gas (11), characterized in that a rotated out of the exhaust stream portion or portion of the filter medium within the rotary particle filter (12) initially in a first outside of the exhaust gas flow lying partial chamber (14) of the rotary particle filter (12) is regenerated under oxidation of soot in the filter medium, that subsequent to this regeneration in a second outside of the exhaust gas flow sub-chamber (15) of the rotary particle filter (12) from the respective rotated out of the exhaust stream part or section of the filter medium ash removed is, and that subsequently to the regeneration and ash removal of the respective rotated out of the exhaust stream portion or portion of the filter medium is screwed into the exhaust stream. 2. The method according to claim 1, characterized in that the regeneration is carried out as active regeneration while heating the respective portion of the filter medium which has been turned out of the exhaust gas flow, wherein for heating the respective active part or section of the filter medium to be regenerated the same in the first outside The exhaust gas flow lying sub-chamber (14) of the rotary particle filter (12) is traversed by air (17), which is preferably heated by a heating device. 3. The method according to claim 1 or 2, characterized in that for the ash removal of the respective out of the exhaust stream rotated portion or portion of the filter medium in the second outside of the exhaust gas flow sub-chamber (15) of the rotary particle filter (12) is flowed through by a solvent (18) , 4. The method according to any one of claims 1 to 3, characterized in that the respective turned out of the exhaust stream part or portion of the filter medium subsequent to the regeneration and ash removal and before screwing into the exhaust stream in a third outside of the exhaust gas flow sub-chamber (19) of the rotary particle filter (12) is heated in order to compensate for an adjusting in the ash removal temperature drop of the filter medium. 5. The method according to claim 2 and 4, characterized in that the active regeneration in the first outside of the exhaust gas flow sub-chamber of the rotary particle filter (12) guided over the respective part or portion of the filter medium, heated air (17) returned to compensate for the In the ash removal adjusting temperature drop of the filter medium in the third outside of the exhaust gas flow sub-chamber (19) of the rotary particle filter (12) is again performed over the respective part or portion of the filter medium. 6. The method according to any one of claims 1 to 5, characterized in that a twisted into the exhaust stream portion or portion of the filter medium for regeneration unscrewed from the exhaust stream and in the first outside of the exhaust gas flow sub-chamber (14) of the rotary particle filter (12) is screwed in that subsequent to the regeneration for ash removal, this section or part of the filter medium is rotated out of the first outside of the exhaust gas flow sub-chamber (14) of the rotary particle filter (12) and in the second outside of the exhaust gas flow sub-chamber (15) of the rotary particle filter (12), which is separated from the first partial chamber (14) of the same, is turned in, and that subsequently to the ash removal this portion or part of the filter medium from the second outside of the exhaust gas flow sub-chamber (15) of the rotary particle filter (12) unscrewed and either directly or m Ittelbarbar via the third outside of the exhaust gas flow sub-chamber (19) of the rotary particle filter (12), which is separated from the flow side of the second partial chamber (15) thereof, is rotated into the exhaust gas flow. 7. The method according to any one of claims 1 to 6, characterized in that in the regeneration of the rotated out of the exhaust stream portion or portion of the filter medium with a flow direction downstream of the rotary particle filter (12) positioned sensor (21), the oxygen content downstream of the rotary particle filter ( 12) and optionally with a sensor (20) positioned upstream of the rotary particle filter (12), the oxygen content upstream of the rotary particle filter (12) is measured, and on the basis of the oxygen content measured by the sensor or sensors, a loading of the rotary particle filter (12 ) with soot before the regeneration and / or a temperature increase of the rotary particle filter (12) as a result of the regeneration and / or a speed of regeneration is determined. 8. A method for exhaust aftertreatment of an internal combustion engine (30) leaving the exhaust gas (31), wherein the exhaust gas (31) via a rotary particle filter (32) is guided, that in the exhaust gas flowed-in part or portion of the filter medium flows around the exhaust gas (31) is, and a rotated out of the exhaust stream portion or portion of the filter medium is not flowed around by the exhaust gas (31), wherein the rotated out of the exhaust stream portion or portion of the filter medium from a lying outside the exhaust flow part chamber (34) of the rotary particle filter (32) and removes outside of the rotary particle filter (32) is freed from soot and ash, then returned to the outside of the exhaust gas flow sub-chamber (34) of the rotary particle filter (32) is returned and screwed back into the exhaust stream. 9. The method according to claim 8, characterized in that as the exhaust gas flowed around the filter medium, a granulate is used, outside of the rotary particle filter (32) via a separator (36) the granules of soot and ash particles and / or reaction products of soot and Ash particle is separated with the granules, and wherein purified granules are recycled to the rotary particle filter (32). 10. The method according to any one of claims 1 to 9, characterized in that upstream of the rotary particle filter (12, 32) in an oxidation catalyst (22) SO2 is oxidized in SO3, wherein the SO3 and / or precipitated H2SO4 of the oxidation of soot in the rotary particle filter ( 12, 32) serves on the part or section of the filter medium which is screwed into the exhaust gas stream, and wherein in the oxidation catalyst (22) as active component for the oxidation of SO 2 in SO 3 at least vanadium with a proportion of more than 5%, preferably more than 7%, particularly preferably more than 9%, and preferably additionally potassium and / or sodium and / or iron and / or cerium and / or cesium and / or oxides of these elements is used, wherein in the oxidation catalyst as the base material titanium oxide and / or silicon oxide preferably stabilized by Tungsten oxide is used. 11. The method according to claim 10, characterized in that downstream of the oxidation catalyst (22) in the region of the rotary particle filter a mass ratio between SO3 and carbon black of at least 7: 1, preferably of at least 12: 1, more preferably of at least 16: 1, is set , 12. The method according to claim 10 or 11, characterized in that upstream of the rotary particle filter (12, 32) in an oxidation catalyst (40) NO in NO2 is oxidized, wherein the NO2 of the oxidation of soot in the rotary particle filter (12, 32) on the in and the oxidation catalyst (40) is connected in parallel to the oxidation catalyst (22) for the oxidation of SO2 in SO3, and both oxidation catalysts (40, 22) are connected via shut-off valves ( 41) are separable from the exhaust stream.