DE102014018211A1 - 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 which is screwed into the exhaust gas flow is passed through by the exhaust gas (11), and that a part or section of the filter medium which has been turned out of the exhaust gas flow is not flowed through by the exhaust gas, the part or section of the filter medium turned out of the exhaust gas flow inside the rotary particle filter (12) initially in a first sub-chamber (14) lying outside the exhaust gas flow of the rotary particle filter (12) is regenerated with oxidation of soot in the filter medium, that after this regeneration in a second outside of the exhaust gas flow sub-chamber (15) of the rotary particle filter (12) is removed from the untwisted from the exhaust stream 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

The invention relates to a method for exhaust 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 disposed in the flow direction of the exhaust gas disposed exhaust aftertreatment assembly. The term particulate filter should be understood as meaning both conventional particulate filters which have a filter medium through which the exhaust gas flows, and also particulate separators in which the exhaust gas flows around a filter medium serving as a precipitation structure.

An exhaust aftertreatment assembly positioned upstream of the particulate filter in the flow direction of the exhaust gas is, in particular, an oxidation catalyst for the oxidation of nitrogen monoxide (NO) into nitrogen dioxide (NO ₂ ).

Then, when seen in the flow direction of the exhaust gas stream is positioned upstream of the particulate filter, an oxidation catalyst for oxidising NO to NO _{2, 2} is oxidized to NO ₂ by the following equation in the oxidation catalyst NO with the aid of the residual oxygen O contained in the exhaust gas stream: 2NO + O ₂ → 2NO ₂

In this oxidation of nitrogen monoxide to nitrogen dioxide, at high temperatures, the equilibrium of the oxidation reaction is 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 form carbon monoxide (CO), carbon dioxide (CO ₂ ), nitrogen (N ₂ ) 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 carbon black deposited in the particulate filter takes place, this conversion taking place according to the following equations: 2NO ₂ + C → 2NO + CO ₂ NO ₂ + C → NO + CO 2C + 2NO ₂ → N ₂ + 2CO ₂

Then, if with such a passive regeneration of the particulate filter, a complete conversion of carbon particulate matter stored in the particulate filter or the soot can not occur, the carbon content or soot content increases in the particulate filter, with a particulate filter with a filter medium flowed through by exhaust gas then tends to block, whereby ultimately a so-called exhaust back pressure rises 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 of the carbon-containing fines particles or of the soot in the particle filter, it is already known from practice to provide the filter medium of a particle filter, through which exhaust gas flows, 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, to an insufficient extent.

Furthermore, it is known from practice to reduce the loading of an exhaust gas-flowed through the filter medium of a particulate filter with soot to use an active regeneration of the filter medium. In such 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: C + O ₂ → CO ₂

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 the 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 a turned into the exhaust stream or portion of the filter medium of the rotary particle filter is traversed by Abas, and wherein a rotated out of the exhaust stream portion or portion of the filter medium of the rotary particle filter not From the Abas but to clean the filter medium is flowed through by 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 the exhaust aftertreatment system according to claim 1.

According to the first aspect of the invention, a part or section of the filter medium turned out of the exhaust gas flow, while the part or section of the filter medium that has been turned into the exhaust gas stream flows through Agas, is first oxidized within the rotary particle filter in a first sub-chamber of the rotary particle filter outside of the exhaust gas flow regenerated by soot in the filter medium, which is followed by 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 removed, and wherein subsequent to the regeneration and ash removal of the respective from the exhaust stream twisted part or portion of the filter medium is screwed into the exhaust stream.

The first aspect of the present invention proposes for the first time, in a rotary particle filter parallel to the exhaust gas purification using the part or section of the filter medium turned into the exhaust gas flow, the part or section of the filter medium turned out of the exhaust gas stream, a regeneration by oxidation of carbon black and then a To undergo 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 the exhaust gas flow sub-chamber of the rotary particle filter, wherein the ash removal takes place in a second, lying outside the exhaust gas flow sub-chamber of the rotary particle filter.

Accordingly, at least three partial 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 partial 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 further development of the first aspect of the invention, the part or section of the filter medium turned out of the exhaust gas stream is heated in the exhaust gas stream in a third sub-chamber of the rotary particle filter outside the exhaust gas flow to regenerate and remove ashes and before turning into the exhaust gas stream Ash removal adjusting temperature drop of the filter medium to compensate.

With this advantageous development it can be avoided that, as a result of a temperature drop of the filter medium occurring during the ash removal, when exhaust gas flows through the corresponding part or section of the filter medium, an exhaust gas-side temperature drop is formed, which subordinates the effectiveness of the exhaust gas aftertreatment in the rotary particle filter Exhaust aftertreatment assemblies, such as in catalysts impaired.

According to a further advantageous development of the first aspect of the invention, a part or section of the filter medium that has been turned into the exhaust gas flow is rotated out of the exhaust gas flow for regeneration and screwed into the first sub-chamber of the rotary particle filter outside the exhaust gas flow, this section then following the regeneration for ash removal or part of the filter medium out of the first out of the exhaust flow sub-chamber of the rotary particle filter and rotated into the second lying outside the exhaust flow sub-chamber of the rotary particle filter, which is on the flow side of the first part of the exhaust gas flow outside thereof, is rotated, and wherein subsequently to the Ash removal of this section or part of the filter medium from the second located outside the exhaust gas flow sub-chamber of the rotary particle filter and either directly or indirectly via the third located outside the exhaust gas flow sub-chamber of the rotary particle filter, which is the same on the flow side separated from the second part of the exhaust gas flow, it 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 carbon black in a particularly advantageous manner.

According to a further advantageous development of the first aspect of the invention, the regeneration is carried out as active regeneration by heating the part or section of the filter medium turned out of the exhaust gas flow, wherein for heating the actively regenerated part or section of the filter medium the same in the first outside of 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 is positioned downstream of the rotary particle filter and optionally with an upstream of the rotary particle filter Sensor, the oxygen content is measured upstream of the rotary particle filter, wherein on the basis of the oxygen content measured by the or each sensor, a loading of the rotary particle filter with soot and / or a temperature increase of the rotary particle filter due to the regeneration and / or a speed of regeneration is determined, and wherein Based on the oxygen content measured by the or each sensor, the active regeneration is regulated. As a result, the active regeneration in the rotary particle filter can be realized particularly advantageously, namely a regulation of the active regeneration while avoiding too 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 system according to claim 8.

According to the second aspect, an exhaust gas leaving an internal combustion engine is passed over a rotary particle filter, that flows around a portion of the filter medium or in the exhaust gas flow from the Abas, and an untwisted from the exhaust stream portion or portion of the filter medium is not flowed around by the Abas, wherein the part or section of the filter medium turned out of the exhaust gas stream is removed from a partial chamber of the rotary particle filter which is outside the exhaust gas flow and freed of soot and ash outside the rotary particle filter, then returned to the partial chamber of the rotary particle filter which is outside the exhaust gas flow and is again screwed into the exhaust gas flow , According to the second aspect of the invention, it is proposed for the first time to use filter medium surrounded by exhaust gas in a rotary particle filter which, when it has been removed from the exhaust gas flow, is removed from the rotary particle filter 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 screwed into the exhaust stream portion or portion of the filter medium, so as from the in To remove the exhaust gas flow part or portion of the filter medium within the rotary particle filter in the sense of regeneration soot. For this purpose, it is preferable to oxidize SO ₂ in SO ₃ in an oxidation catalyst SO ₂ arranged upstream of the rotary particle filter, the SO ₃ and / or precipitated H ₂ SO ₄ serving to oxidize soot in the rotary particle filter on the part or section of the filter medium screwed into the exhaust gas flow, and in the oxidation catalyst as the 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%, 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.

For 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 drawings. Showing:

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

2 : a cross section through the rotary particle filter the 1 ;

3 : is a block diagram to illustrate a second variant of the method according to the invention for exhaust gas aftertreatment according to the first aspect of the invention;

4 : a cross section through the rotary particle filter the 3 ;

5 a block diagram illustrating a first variant of the inventive method for exhaust aftertreatment according to the second aspect of the invention;

6 : a cross section through the rotary particle filter the 5 ;

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

8th : is a block diagram to illustrate a third variant of the inventive method for exhaust 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 operated with excess air Large internal combustion engines are used, for example in marine diesel engines.

With reference to 1 and 2 Below is an inventive method for exhaust aftertreatment of an internal combustion engine 10 leaving exhaust 11 described according to a first aspect of the invention. So shows 1 an internal combustion engine 10 , wherein the internal combustion engine 10 leaving exhaust 11 via a rotary particle filter 12 for exhaust aftertreatment is performed.

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 section or part of the filter medium through which exhaust gas flows and thus into the exhaust gas flow is in a partial chamber 13 of the rotary particle filter 12 positioned, which is traversed by exhaust gas.

The part or section of the filter medium turned out of the exhaust gas stream becomes inside the rotary particle filter 12 initially in a first outside the exhaust gas flow sub-chamber 14 of the rotary particle filter 12 regenerated under oxidation of soot in the filter medium, wherein subsequent to this regeneration of the filter medium of this rotated out of the exhaust stream portion or portion of the filter medium in a second outside of the exhaust gas flow sub-chamber 15 of the rotary particle filter 12 ash is removed by removing ash from that part or portion of the filter media.

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

With reference to 1 and 2 Accordingly, the exhaust aftertreatment process described uses at least three subchambers of the rotary particle filter 12 that is, a partial chamber located in the exhaust gas flow 13 as well as the two subchambers located outside the exhaust gas flow 14 and 15 , wherein the filter medium by rotating the same in the direction of the arrow 16 Sectionwise 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 to the compartment 13 can be shifted so as to parallel to the exhaust aftertreatment in the sub-chamber 13 serial regeneration in the sub-chamber 14 and the ash removal in the compartment 15 make.

The section-by-section or partial regeneration of the filter medium turned out of the exhaust gas flow in the sub-chamber 14 of the rotary particle filter 12 is preferably carried out as an active regeneration and the heating of the portion of the filter medium turned out of the exhaust gas flow, for which purpose the heating of the actively regenerating part or portion of the filter medium is in the sub-chamber located outside the exhaust gas flow 14 of the rotary particle filter 12 from heated air 17 is flowed through, which can be heated to a defined temperature, for example by means of a heater, not shown, so as to actively heat the regenerating part or portion of the filter medium for active regeneration to a defined process temperature.

Following the preferably active regeneration of a part or section of the filter medium in the sub-chamber which has been turned out of the exhaust-gas stream 14 of the rotary particle filter 12 becomes 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 is subjected to ash removal by removing ash from the previously regenerated part or section of the filter medium, to which this part or portion of the filter medium is preferably removed from a solvent 18 is flowed through.

With this solvent 18 it can be, for example, water or sulfuric acid.

Are sulfate-containing ash deposits from the filter medium of the rotary particle filter 12 As a solvent, a solution containing sodium carbonate through the part or section of the filter medium, which is in the sub-chamber 15 of the rotary particle filter 12 is to be guided. 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 with water from the filter medium. As an example for CaSO ₄ , this is done as follows: CaSO ₄ + Na ₂ CO ₃ → CaCO ₃ + Na ₂ SO ₄ CaCO ₃ + 2HCl → CaCl ₂ + H ₂ O + CO ₂

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 Exhaust gas flows through the filter medium that is screwed in, and one of these partial chambers 13 and therefore part or section of the filter medium turned out of the exhaust gas flow in a first sub-chamber located outside the exhaust gas flow 14 a regeneration by oxidation of soot and subsequently in a further outside the exhaust gas flow sub-chamber 15 is subjected to an ash removal.

Accordingly, filter medium screwed into the exhaust gas flow is regenerated from the exhaust gas flow and thus the partial chamber 13 turned out and first in the first outside of the exhaust gas flow sub-chamber 14 of the particulate filter 12 screwed in to get into this subchamber 14 to be regenerated, wherein subsequent to the regeneration in the lying outside of the exhaust gas flow subchamber 14 of the rotary particle filter 12 the corresponding part or section of the filter medium from the first sub-chamber located outside of the exhaust gas flow 14 of the rotary particle filter 12 turned out and in the second outside of the exhaust flow sub-chamber 15 of the rotary particle filter is turned to in this sub-chamber 15 coming from the sub-chamber 14 is separated on the flow side, to carry out the ash removal.

Advantageous developments of the reference to 1 and 2 described exhaust gas aftertreatment method according to the first aspect of the invention are described below with reference to 3 and 4 described, in 3 and 4 for same components, the same reference numbers are used as in 1 and 2 , Therefore, to avoid unnecessary repetition regarding this in 3 and 4 identical assemblies to the relevant versions 1 and 2 directed.

A first difference of 3 and 4 in comparison to the 1 and 2 is that in 3 and 4 the rotary particle filter 12 in addition to the two sub-chambers located outside the exhaust gas flow 14 and 15 another sub-chamber located outside the exhaust gas flow 19 comprising, wherein that portion or part of the filter medium, which is located in this third outside of the exhaust gas flow partial chamber 19 is located, following the ash removal and before screwing into the exhaust gas flow through the sub-chamber 13 and therefore before screwing into the exhaust gas flow within the sub-chamber 19 is heated to compensate for an adjusting in the ash removal temperature drop of the filter medium. This will be in 3 by doing that the heated air 17 , which are for active regeneration in the first out of the exhaust flow sub-chamber 14 of the particulate filter 12 is guided over the filter medium located in the same, returned and then over the sub-chamber 19 or in the sub-chamber 19 is guided 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 screwed into the exhaust gas flow, the exhaust gas is cooled at the same, which can ensure that, if necessary, downstream of the rotary particle filter 12 positioned further exhaust aftertreatment assemblies can be operated at optimum process temperature of the exhaust gas.

Another difference of the embodiment of 3 and 4 compared to the embodiment of the 1 and 2 is that in 3 and 4 both upstream of the rotary particle filter 12 as well as downstream of each a sensor 20 respectively. 21 is present, with the aid of those upstream and downstream of the rotary particle filter 12 namely, upstream and downstream of the first sub-chamber located outside the exhaust gas flow 14 of the rotary particle filter 12 , the oxygen content in the active regeneration over the first sub-chamber 14 guided air can be measured.

Based on the from the sensors 20 . 21 detected oxygen content may be a loading of the respective part or portion to be regenerated of the filter medium of the rotary particle filter 12 with soot before regeneration and / or a temperature increase due to the regeneration and / or a speed of regeneration are determined, for example, if too high a temperature increase 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 , the sensor 21 is measured, and additionally from the oxygen content upstream of the rotary particle filter 12 , the sensor 20 the amount of soot burned off can be determined according to the following equation: C + O ₂ → CO ₂

Each oxygen molecule burned corresponds to one carbon molecule. By integration over time, the loading of the respective part or section of the filter medium of the rotary particle filter to be regenerated can be so 12 be determined with soot before Rußabbrand.

The temperature rise due to Rußabbrands can be determined according to the following equation: ΔT = m _c × Hu _c / Δt × d / dt (m) × α where ΔT corresponds to the temperature rise due to the soot burnup, m _c corresponds to the loading of the respective part or section of the filter medium to be regenerated with soot before soot burn off, Hu _c corresponds to the calorific value of the soot, Δt corresponds to the soot burn time, d / dt (m) corresponds to the air mass flow, and α corresponds to the heat capacity of the air.

Upstream of the rotary particle filter 12 For example, an oxidation catalyst (not shown) for oxidizing NO to NO _{2 may be} positioned to be in the subchamber 13 and thus provide NO _{2 to the} part or section of the passive regeneration filter medium 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% % lies to an optimal passive regeneration of the filter medium within the sub-chamber 13 and use of NO ₂ . The desired NO ₂ content of the total NO _x fraction can be adjusted by the NO oxidation catalyst, possibly assisted by a lowering of the combustion temperature in the internal combustion engine.

In the embodiment of 3 and 4 is upstream of the rotary particle filter 12 an oxidation catalyst 22 for the oxidation of SO ₂ in SO ₃ , wherein the oxidation in the catalyst 22 produced SO ₂ and / or precipitating H ₂ SO ₄ can be used to in the exhaust gas flowed through the filter medium within the sub-chamber 13 of the rotary particle filter 12 To oxidize soot. SO ₃ + O → CO + SO ₂ 2SO ₃ + O → CO ₂ + 2SO ₂

As an active component for the oxidation of SO ₂ in SO ₃ is in the oxidation catalyst 22 at least vanadium in a proportion of more than 5%, preferably of more than 7%, more preferably of more than 9% used, wherein as additional active components for the oxidation of SO ₂ in SO ₃ optionally 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 For example, titanium oxide or silicon oxide, preferably stabilized by tungsten oxide, is used as the base material to oxidize SO ₂ in SO ₃ .

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

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

An embodiment of a method according to a second aspect of the present invention will be described below with reference to FIG 5 and 6 described, in 5 an internal combustion engine 30 is shown, the exhaust gas 31 via a rotary particle filter 32 for exhaust aftertreatment is performed. The rotary particle filter 32 takes on a filter medium, which in contrast to the embodiments of the 1 to 4 Does not flow through exhaust gas, but rather is flowed around by exhaust gas. This filter medium is preferably a granulate, with soot and ash or reaction products of soot and ash depositing in the exhaust gas aftertreatment on the granules.

The rotary particle filter 32 according to 6 over two subchambers 33 . 34 , namely a partial chamber located in the exhaust gas flow 33 and a sub-chamber located outside the exhaust stream 34 , Filter medium, which is in the sub-chamber 33 Exhaust gas flows around, whereas filter medium, which is located in the partial chamber, is located 34 is located, is not surrounded by exhaust gas. The filter medium can be in the direction of the arrow 35 from the first compartment 33 of the rotary particle filter 32 into the second compartment 34 of the rotary particle filter 32 screwed in and therefore be rotated out of the exhaust gas flow, as well as filter medium from the second sub-chamber 34 of the rotary particle filter 32 into the first compartment 33 of the rotary particle filter 32 be transferred and therefore screwed into the exhaust stream.

According to the second aspect of the invention is filter medium, which in the sub-chamber 33 of the rotary particle filter 32 is surrounded by exhaust gas, then, if the same in the sub-chamber 34 of the rotary particle filter 32 was shifted and therefore was turned out of the exhaust flow, from the sub-chamber 34 of the rotary particle filter 32 removed and a separator 36 fed. The arrow 37 in 5 Visualizes the removal of filter medium or granules from the sub-chamber 34 of the rotary particle filter 32 and transferring it to the separator 36 ,

In the separator 36 the filter medium, which is preferably granules, removes soot and ash, in particular by a mechanical peeling process, for example with the aid of a separator designed as a drum peeler 36 to subsequently purified granules in the direction of the arrow 38 again the rotary particle filter 32 namely, the second sub-chamber 34 the same, and subsequently again in the direction of the arrow 35 in the sub-chamber 33 and turn the exhaust gas flow into it. Soot and ash particles and / or reaction products of soot and ash particles with the granules which are in the separator 36 were separated from the granules are in the direction of the arrow 39 from the separator 36 dissipated.

7 clarifies a further education with reference to 5 and 6 described method, wherein in 7 in accordance to 3 upstream of the rotary particle filter 12 an oxidation catalyst 22 For the oxidation of SO ₂ in SO _{3 is} positioned, which by the oxidation catalyst 22 produced SO ₂ and / or precipitated H ₂ SO _{4 of} the oxidation of soot directly in the rotary particle filter 32 serves, that is, in that filter medium, which is located in the exhaust gas flow through the partial chamber 33 of the rotary particle filter 32 located.

This is again in the oxidation catalyst 22 used as the active component for the oxidation of SO ₂ in SO ₃ at least vanadium, preferably additionally potassium and / or sodium and / or iron and / or cerium and / or cesium and / or oxides of these elements, in the oxidation catalyst 22 the base material is titanium oxide or silicon oxide, preferably stabilized by tungsten oxide.

In this case, the vanadium content is at least 5%, more preferably at least 7%, particularly preferably at least 9%, wherein downstream of the oxidation catalyst 22 in the area of the rotary particle filter 32 , namely in the area of the sub-chamber 33 the same, a mass ratio between SO ₃ and carbon black of at least 7: 1, preferably of at least 12: 1, more preferably of at least 16: 1, is set. In the variant of 7 Accordingly, on the one hand, oxidation of soot takes place in the rotary particle filter 32 , namely within the sub-chamber through which exhaust gas flows 33 the same, on the other hand, the filter medium outside the rotary particle filter 32 in the separator 36 Soot removed.

8th shows a development of the method of 7 in which upstream of the rotary particle filter 32 not just the oxidation catalyst 22 which serves to oxidize SO ₂ in SO ₃ , but moreover is another oxidation catalyst 40 which serves to oxidise NO to NO ₂ . These two oxidation catalysts 22 . 40 are connected in parallel with each other, each of the oxidation catalysts 22 and 40 via shut-off valves 41 Can be shut off or separated from exhaust gas flow. Will high sulfur fuel in the engine 30 used, then the exhaust gas flow over the oxidation catalyst 22 led to the oxidation of SO ₂ in SO ₃ and the NO oxidation catalyst 40 will be over the valve 41 separated from the exhaust gas flow. As a result, the NO oxidation catalyst 40 , which serves the oxidation of NO in NO ₂ , kept sulfur-free. If, however, a relatively weak sulfur-containing fuel is used, the SO ₂ oxidation catalyst can be used 22 by closing the corresponding valves 41 be separated from the exhaust stream and the exhaust gas is via the NO oxidation catalyst 40 led to the oxidation of NO in NO ₂ . The variant of 8th 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 8th this is, on the shut-off valves 41 to dispense and the oxidation catalyst 40 to be able to be used after operation with a fuel containing a high sulfur content in such a way that the exhaust gas temperature is raised and thus in the oxidation catalytic converter 40 Sulfur is desorbed. The variant with the shut-off valves 41 However, it is preferred because then after operation of the internal combustion engine 1 with sulfur-containing fuel, the oxidation catalyst 40 then immediately ready for use.

As granules can in the rotary particle filter 32 kataytisch inactive granules are used. 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 with the granules in the rotary particle filter 32 react.

Then, when catalytically active granules are used, comes as a separator 36 preferably a drum peeler used. Then, if catalytically inactive granules is used, can as a separator 36 Also a drum screen, a vibrating screen, a mill or a watch device, the water used as a wax medium, to clean the granules.

The rotary particle filter 32 can be multi-level. In the rotary particle filter 32 Exhaust gas to be purified then flows first through a first stage and subsequently to 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 area of each of the stages, the granules are rotatable out of the exhaust gas flow, outside the stage of the rotary particle filter 32 in a separator 36 released from soot and ash and then again the respective stage of the rotary particle filter 32 fed.

Then, if like in 2 shown, the rotary particle filter 32 executed in several stages, preferably deviates 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.

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

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.

LIST OF REFERENCE NUMBERS

10

Internal combustion engine

11

exhaust

12

rotation particle filter

13

member chamber

14

member chamber

15

member chamber

16

direction of rotation

17

air

18

solvent

19

member chamber

20

sensor

21

sensor

22

oxidation catalyst

30

Internal combustion engine

31

exhaust

32

rotation particle filter

33

member chamber

34

member chamber

35

direction of rotation

36

Separation Eirich Tung

37

granules

38

granules

39

Soot / ash

40

oxidation catalyst

41

Absperrvenil

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5013340 [0010]

Claims (12)

Process for the exhaust aftertreatment of an internal combustion engine ( 10 ) leaving exhaust gas ( 11 ), the exhaust gas ( 11 ) via a rotary particle filter ( 12 ), a part or section of the filter medium which is screwed into the exhaust gas stream is separated from the exhaust gas ( 11 ) is flowed through, and that a rotated out of the exhaust stream part or portion of the filter medium is not from the exhaust gas ( 11 ) is flowed through, characterized in that a rotated out of the exhaust stream part or portion of the filter medium within the rotary particle filter ( 12 ) first in a first outside the exhaust gas flow sub-chamber ( 14 ) of the rotary particle filter ( 12 ) is regenerated under oxidation of soot in the filter medium, that after this regeneration in a second outside of the exhaust gas flow sub-chamber ( 15 ) of the rotary particle filter ( 12 ) is removed from the respective part of the filter medium removed from the exhaust gas stream or ash, and that after the regeneration and ash removal, the respective part or section of the filter medium turned out of the exhaust gas stream is screwed into the exhaust gas stream. A method according to claim 1, characterized in that the regeneration is carried out as an active regeneration by heating the respective part or portion of the filter medium turned out of the exhaust stream, wherein for heating the respective active part or portion of the filter medium to be actively regenerated in the first outside of the exhaust gas flow lying partial chamber ( 14 ) of the rotary particle filter ( 12 ) of air ( 17 ) is flowed through, which is preferably heated with a heater. A method according to claim 1 or 2, characterized in that for ash removal, the respective portion of the filter medium which has been turned out of the exhaust gas stream or in the second sub-chamber located outside the exhaust gas flow (US Pat. 15 ) of the rotary particle filter ( 12 ) of a solvent ( 18 ) is flowed through. Method according to one of claims 1 to 3, characterized in that the respective turned out of the exhaust stream portion 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 to compensate for a drop in temperature of the filter medium as the ash is removed. A method according to claim 2 and 4, characterized in that the active regeneration in the first lying outside of the exhaust gas flow partial chamber of the rotary particle filter ( 12 ) via the respective part or section of the filter medium guided, heated air ( 17 ) and for compensating for the temperature drop of the filter medium which occurs during the ash removal in the third sub-chamber located outside the exhaust gas flow (US Pat. 19 ) of the rotary particle filter ( 12 ) is again passed over the respective part or section of the filter medium. Method according to one of claims 1 to 5, characterized in that a rotated into the exhaust gas flow part or portion of the filter medium for regeneration out of the exhaust stream and into the first outside of the exhaust gas flow sub-chamber ( 14 ) of the rotary particle filter ( 12 ) is turned in, that following the regeneration for ash removal of this section or part of the filter medium from the first out of the exhaust gas flow sub-chamber ( 14 ) of the rotary particle filter ( 12 ) and into the second partial chamber (outside of the exhaust gas flow) ( 15 ) of the rotary particle filter ( 12 ), the flow side of the first partial chamber ( 14 ) of the same is separated, is rotated, and that subsequent to the ash removal of this portion or part of the filter medium from the second out of the exhaust gas flow sub-chamber ( 15 ) of the rotary particle filter ( 12 ) and either directly or indirectly via the third sub-chamber lying outside the exhaust gas flow ( 19 ) of the rotary particle filter ( 12 ), the flow side of the second sub-chamber ( 15 ) thereof is separated, is screwed into the exhaust gas flow. Method according to 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 downstream seen in the flow direction of the rotary particle filter ( 12 ) positioned sensor ( 21 ) the oxygen content downstream of the rotary particle filter ( 12 ) and optionally with a flow direction seen upstream of the rotary particle filter ( 12 ) positioned sensor ( 20 ) the oxygen content upstream of the rotary particle filter ( 12 ) and that, based on the oxygen content measured by the sensor or the sensors, a loading of the rotary particle filter ( 12 ) with soot before regeneration and / or a temperature rise of the rotary particle filter ( 12 ) is determined as a result of the regeneration and / or a speed of regeneration. Process for the exhaust aftertreatment of an internal combustion engine ( 30 ) leaving exhaust gas ( 31 ), the exhaust gas ( 31 ) via a rotary particle filter ( 32 ), that one in the Exhaust gas flowed-in part or section of the filter medium from the Abas ( 31 ), and a part or section of the filter medium which has been turned out of the exhaust gas stream and not from the Abas ( 31 ), whereby the part or section of the filter medium turned out of the exhaust gas stream flows from a sub-chamber located outside the exhaust gas flow (US Pat. 34 ) of the rotary particle filter ( 32 ) and outside the rotary particle filter ( 32 ) is freed of soot and ash, then into 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. A method according to claim 8, characterized in that as the exhaust gas flowing around the filter medium, a granulate is used, wherein outside the rotary particle filter ( 32 ) via a separating device ( 36 ) the granules of soot and ash particles and / or reaction products of the carbon black and ash particles is separated with the granules, and wherein purified granules the rotary particle filter ( 32 ) is returned. Method according to one of claims 1 to 9, characterized in that upstream of the rotary particle filter ( 12 . 32 ) in an oxidation catalyst ( 22 ) SO _{2 is} oxidized in SO ₃ , wherein the SO ₃ and / or precipitated H ₂ SO _{4 of} the oxidation of soot in the rotary particle filter ( 12 . 32 ) is used at the part or section of the filter medium which is screwed into the exhaust gas flow, and wherein in the oxidation catalytic converter ( 22 ) as the 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%, 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 is preferably used stabilized by tungsten oxide. Process 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 SO ₃ and carbon black of at least 7: 1, preferably of at least 12: 1, more preferably of at least 16: 1, is set. A method according to claim 10 or 11, characterized in that upstream of the rotary particle filter ( 12 . 32 ) in an oxidation catalyst ( 40 NO is oxidized to NO ₂ , the NO _{2 of} the oxidation of soot in the rotary particle filter ( 12 . 32 ) is used on the part or section of the filter medium which is screwed into the exhaust gas flow, and in which the oxidation catalytic converter ( 40 ) for the oxidation of NO in NO ₂ parallel to the oxidation catalyst ( 22 ) for the oxidation of SO ₂ in SO ₃ , and wherein both oxidation catalysts ( 40 . 22 ) via shut-off valves ( 41 ) are separable from the exhaust stream.

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