JP6636259B2 - Exhaust gas aftertreatment system and method for exhaust gas aftertreatment - Google Patents

Description

  The present invention relates to an exhaust gas aftertreatment system. Furthermore, the invention relates to a method for exhaust gas aftertreatment.

During the combustion process in a stationary internal combustion engine used for example in a power plant and in a non-stationary internal combustion engine used in a ship for example, sulfur oxides such as SO ₂ and SO ₃ are produced. These sulfur oxides are typically formed during the combustion of sulfur-containing fossil fuels such as coal, wellhead coal, lignite, oil, or heavy oil. Therefore, such internal combustion engines are specifically provided with an exhaust gas aftertreatment system which serves for desulfurization of the exhaust gases leaving the internal combustion engine.

To desulfurize exhaust gas, as an absorbent, quick lime (CaO), slaked lime (Ca _(OH) 2), or the method according to absorption primarily used calcium carbonate (CaCO ₃₎ is known mainly from the prior art ing. In the process, a powder or granules are formed and a filter device needs to be used downstream of desulfurization to remove the calcium sulfate powder from the exhaust gas.

  From US Pat. No. 6,037,098, a method and an exhaust gas aftertreatment system for the treatment of exhaust gases containing nitrogen dioxide and powder are known.

Japanese Patent No. 3603365

  Thus, it is an object of the present invention to create a new type of exhaust gas aftertreatment system and a method for a new type of exhaust gas aftertreatment.

  This object is solved by an exhaust gas aftertreatment system according to claim 1. An exhaust gas aftertreatment system for an internal combustion engine according to the present invention comprises a separator disposed downstream of the internal combustion engine and comprising calcium-containing particles for chemisorbing sulfur oxides. Furthermore, the exhaust gas aftertreatment system according to the present invention is directed on the one hand to the exhaust gas guided through the separator and on the other hand to leave the internal combustion engine in order to increase the temperature of the exhaust gas leaving the internal combustion engine. A gas-gas heat exchanger through which incoming exhaust gases can be directed. Furthermore, the exhaust gas aftertreatment system according to the invention is arranged downstream of the gas-gas heat exchanger and upstream of the separator in order to further increase the temperature of the exhaust gas guided through the gas-gas heat exchanger. Equipped heating device.

  By using a separator, it is possible to omit a filter device for removing calcium sulfate powder or particulates from exhaust gas. The sulfur oxides react with the calcium-containing granules of the separator and can be discharged as granules. A gas-gas heat exchanger and a heating device arranged downstream of the gas-gas heat exchanger heat the exhaust gas guided through the separator to a temperature optimum for desulfurization of the exhaust gas in the separator. It can be controlled and follows the temperature control of the exhaust gas in the gas-gas heat exchanger, so that the circuit of the heating device can be reduced. By controlling the temperature of the exhaust gas led through the separator to a temperature optimum for the desulfurization of the exhaust gas in the separator, the desulfurization of the exhaust gas in the separator is ensured in a short reaction time. This further ensures that relatively little calcium-containing granules are required for desulfurizing the exhaust gas in the separator.

  Preferentially, the gas-gas heat exchanger heats the exhaust gas leaving the internal combustion engine to a temperature between 330 ° C and 350 ° C, preferably between 340 ° C and 350 ° C. The heating device heats the exhaust gas to a temperature between 375 ° C and 450 ° C, preferably between 400 ° C and 450 ° C, most preferably between 360 ° C and 420 ° C. This temperature control of the exhaust gas is effective and is particularly advantageous with regard to the desulfurization of the exhaust gas in the separator.

According to an advantageous further development, an oxidation catalytic converter for oxidizing SO ₂ to SO ₃ is located downstream of the heating device and upstream of the separator, through which the catalytic converter is heated. Exhausted exhaust gas may be directed upstream of the separator. By using an oxidation catalytic converter to oxidize SO ₂ to SO ₃ , the residence time of the exhaust gas in the separator is reduced because SO ₃ reacts more quickly with the calcium-containing particulates of the separator than SO _2. Can be much shorter. This enables a particularly effective desulfurization of the exhaust gas.

According to a further advantageous further development, the device is located downstream of the heating device and upstream of the separator, through which the calcium- and / or sodium-containing powder is passed in the heating device upstream of the separator. It can be introduced into the heated exhaust gas. This enables a particularly effective desulfurization of the exhaust gas. Calcium sulfate powder and / or sodium sulfate powder, or sulfate-containing particulates formed during desulfurization, can be effectively separated from exhaust gas by using a separator. In particular, in addition to the device through which the calcium- and / or sodium-containing powder or granules can be introduced into the exhaust gas which is heated in the heating device upstream of the separator, the oxidation catalytic converter is also heated. If downstream of the device positioned upstream of the separator, apparatus through such calcium-containing and / or sodium-containing powder or granules can be introduced into the exhaust gas, for the oxidation and the sO ₂ to sO ₃ It is located downstream of the oxidation catalytic converter and upstream of the separator.

  According to an advantageous further development, the exhaust gas aftertreatment system comprises an SCR catalytic converter, the SCR catalytic converter being located downstream of the separator and upstream of the gas-gas heat exchanger or alternatively of the gas-gas heat exchanger. -Either located downstream of the gas heat exchanger. In the SCR catalytic converter, denitrification of exhaust gas and thereby further reduction of exhaust gas emission are performed.

  A method for exhaust gas aftertreatment according to the invention is defined in claim 12.

  Preferred further developments of the invention follow from the dependent claims and the following description. BRIEF DESCRIPTION OF THE DRAWINGS Exemplary embodiments of the present invention will be described in more detail, using, but not limited to, the drawings.

1 is a block diagram of a first exhaust gas aftertreatment system according to the present invention. FIG. 4 is a block diagram of a second exhaust gas aftertreatment system according to the present invention. FIG. 4 is a block diagram of a third exhaust gas aftertreatment system according to the present invention. FIG. 9 is a block diagram of a fourth exhaust gas aftertreatment system according to the present invention. FIG. 4 is a block diagram of a further exhaust gas aftertreatment system according to the present invention.

  The present invention relates to an exhaust gas aftertreatment system for an internal combustion engine, for example, for an internal combustion engine that is stationary in a power plant or for an internal combustion engine that is not stationary on a ship.

  Specifically, exhaust gas aftertreatment systems are used in marine diesel engines that operate on heavy oil.

  FIG. 1 shows a first exemplary embodiment of an exhaust gas aftertreatment system 2 arranged downstream of an internal combustion engine 1, wherein the exhaust gas aftertreatment system 2 according to the invention reduces calcium-containing granules or lime. A separator 3 comprising granules based on calcium is provided, wherein the granules based on calcium or on lime act in the separator 3 to chemisorb sulfur oxides. The separator 3 may be a so-called packed bed reactor, or a so-called moving bed reactor or fluidized bed reactor.

Granules used in the separator 3 for chemisorption of sulfur oxides, Preferentially, including CaO and / or Ca _{(OH) 2} and / or CaCO _3. In the process, the sulfur oxides of the exhaust gas react with the calcium-containing granules according to the following reaction formula. That is, Ca (OH) ₂ follows the following reaction formula.
Ca (OH) ₂ + SO ₂ ⇔CaSO ₃ + H ₂ O
Ca (OH) ₂ + SO ₂ + ／ O ₂ ⇔CaSO ₄ + H ₂ O
Ca (OH) ₂ + CO ₂ ⇔CaCO ₃ + H ₂ O
Ca (OH) ₂ + SO ₃ ⇔CaSO ₄ + H ₂ O
For CaCO ₃ , the following reaction equation follows.
CaCO ₃ + SO ₂ ⇔CaSO ₃ + CO ₂
CaCO ₃ + SO ₂ + ／ O ₂ ⇔CaSO ₄ + CO ₂
CaCO ₃ + SO ₃ ⇔CaSO ₄ + CO ₂

  Exhaust gas led through the separator 3 is exhaust gas leaving the internal combustion engine 1 that needs to be later led through the separator 3 and at the same time gas-gas heat exchange of the exhaust gas aftertreatment system 2 Can be guided through the vessel 4. During the chemisorption of the sulfur oxides in the separator 3, heat is generated as a result of the exothermic reaction, so that the exhaust gas already led through the separator 3 is higher than the exhaust gas leaving the internal combustion engine 1. Exhaust gases leaving the internal combustion engine 1 which have a high temperature and consequently in the gas-gas heat exchanger 4, which later need to be led through the separator 3, pass through the separator 3 It can be heated by the exhaust gas already led. Downstream of the gas-gas heat exchanger 4 and upstream of the separator 3, a heating device 5 of the exhaust gas aftertreatment system 2 according to the invention is located, and the heating device 5 is guided through the gas-gas heat exchanger 4. This serves to further increase the temperature of the exhaust gas already heated in the gas-gas heat exchanger 4.

  Thus, the heating of the exhaust gas leaving the internal combustion engine 1 upstream of the separator 3 takes place on the one hand in the gas-gas heat exchanger 4 and in the heating device 5 downstream of the gas-gas heat exchanger 4. Happens in stages. In the gas-gas heat exchanger 4, the increased temperature of the exhaust gas already led through the separator 3 is used to heat the exhaust gas leaving the internal combustion engine 1. The exhaust gas leaving the internal combustion engine 1 typically has a temperature of less than 320 ° C. By means of the gas-gas heat exchanger 4, the exhaust gas leaving the internal combustion engine 1 can be heated to a temperature between 330C and 350C, preferably between 340C and 350C. The further heating of the exhaust gas upstream of the separator 3 and the consequent increase in temperature, starting from the above-mentioned temperature height, via a heating device 5 located downstream of the gas-gas heat exchanger 4 As a result, the heating device 5 heats the exhaust gas to a temperature between 375 ° C and 450 ° C, preferably between 400 ° C and 450 ° C.

  Due to the temperature control of the exhaust gas upstream of the separator 3 where the sulfur oxides of the exhaust gas react with the calcium-containing granules of the separator 3 in order to chemisorb the sulfur oxides, the sulfur oxides of the exhaust gas It can react with the calcium-containing granules of the separator 3 at an optimum process temperature so that the residence time of the exhaust gas in the separator 3 can be made possible. Furthermore, specifically, when the exhaust gas treated in the separator 3 is directed through the separator 3 at the above-mentioned exhaust gas temperature, a relatively small amount of reducing agent, and thus a relatively small amount of calcium-containing particles, Required in separator 3 to chemisorb sulfur oxides. Therefore, as a whole, a very effective exhaust gas after-treatment or exhaust gas desulfurization can be ensured in the separator 3.

  As already explained above, the chemisorption of sulfur oxides in the separator 3, ie the reaction of the sulfur oxides of the exhaust gas with the calcium-containing particulates in the separator 3, This is an exothermic reaction taking gas into consideration. This thermal energy released during the exothermic reaction in the separator 3 is used in the gas-gas heat exchanger 4 in order to have already raised the exhaust gas leaving the internal combustion engine 1 to an intermediate temperature. Used. For this reason, preferentially, the heating device 5, which can be a fuel-operated combustor or an electric heating device, can be miniaturized. For this reason, the efficiency of the exhaust gas aftertreatment system 2 according to the present invention can be enhanced.

  In the exemplary embodiment shown in FIG. 1, the SCR catalytic converter 6 is located downstream of the separator 3 which functions to desulfurize the exhaust gas, and the SCR catalytic converter 6 is configured to denitrify the exhaust gas. Function. Accordingly, the SCR catalytic converter 6 is positioned downstream of the separator 3 and upstream of the gas-gas heat exchanger 4 in FIG.

  In the SCR catalytic converter 6, ammonia is used as a reducing agent. The ammonia utilized in the SCR catalytic converter 6 may be injected directly into the exhaust gas upstream of the SCR catalytic converter 6 by a nozzle between the separator 3 and the SCR catalytic converter 6, or alternatively, the exhaust gas May be introduced downstream of the separator 3 and upstream of the SCR catalytic converter 6. Such a precursor is specifically urea.

  In the exemplary embodiment of FIG. 1, the exhaust heat recovery device 7 is located downstream of the gas-gas heat exchanger 4, and the residual heat of the exhaust gas is used to further increase the efficiency of the exhaust gas aftertreatment system 2. And is utilized downstream of the gas-gas heat exchanger 4 to guide exhaust gases having a temperature of approximately 100 ° C. to the environment downstream of the exhaust gas aftertreatment system 2.

  It is noted here that the SCR catalytic converter 6 may be located downstream of the gas-gas heat exchanger 4 and upstream of the exhaust gas aftertreatment device 7. In this case, the exhaust gas leaving the separator 3 is directed firstly through the gas-gas heat exchanger 4 and then through the SCR catalytic converter 6.

  FIG. 2 is a second exemplary embodiment of an exhaust gas aftertreatment system 2 arranged downstream of the internal combustion engine 1, wherein the exhaust gas aftertreatment system 2 of FIG. 1 in that the oxidation catalytic converter 8 is positioned upstream of the separator 3 and downstream of the heating device 5.

In the oxidation catalytic converter 8, SO ₂ reacts with SO ₃ according to the following reaction formula.
2SO ₃ + O ₂ → 2SO ₂

The following chemical elements, the SO ₂ to oxidize to SO _3, are used as active ingredients in the oxidation catalytic converter 8. That is, V (vanadium), and / or platinum / palladium, and / or Fe (iron), and / or Ce (cerium), and / or Cs (cesium), and / or It is an oxide. The component of vanadium (V) is preferentially higher than 5%, preferably higher than 7% and most preferably higher than 9%.

As the base material, the oxidation catalytic converter 8 uses TiO ₂ (titanium oxide) and / or SiO ₂ (silicon oxide) that is preferentially stabilized by WO ₃ (tungsten oxide).

Since SO ₃ reacts with the calcium-containing granulate quickly separator 3 than SO _2, upstream of the separator 3, it is advantageous to the oxidation catalytic converter 8 for the oxidation and the SO ₂ to SO ₃ is arranged It is. For this reason, the effect of desulfurization can be enhanced. Preferentially, oxidizing SO ₂ to SO ₃ in oxidation catalytic converter 8 means that, downstream of oxidation catalytic converter 8, the component of SO ₃ in all sulfur oxides (SO _X ) of the exhaust gas is It is achieved in such a way that it is at least 20%, preferably more than 40%, most preferably more than 60%.

  FIG. 3 shows an alternative advantageous further development of the exemplary embodiment of FIG. 1 in which the exhaust gas aftertreatment system 2 of FIG. 3 comprises a device 9 downstream of the heating device 5 and upstream of the separator 3. Is different from the exhaust gas after-treatment system 2 of FIG. Through the device 9, calcium- and / or sodium-containing powder can be introduced into the exhaust gas heated by the heating device 5 upstream of the separator 3 containing the calcium-containing granules.

  The device 9 of the exhaust gas aftertreatment system 2 of FIG. 3 functions to introduce calcium- and / or sodium-containing powder into the exhaust gas of the internal combustion engine 1 and has a particle size of less than 1 mm, preferably A calcium- and / or sodium-containing powder having a particle size of less than 0.5 mm, most preferably less than 0.25 mm, is introduced into the exhaust gas and the calcium and / or sodium of the calcium- and / or sodium-containing powder is introduced. Has at least an oxidation step +1.

Preferentially, the powder of the calcium-containing and / or sodium-containing includes CaO and / or Ca _{(OH) 2} and / or CaCO ₃ and / or NaHCO _3.

  Apparatus 9 introduces the calcium- and / or sodium-containing powder into the exhaust gas either as an aerosol using air as a carrier gas or moistened as an emulsion using water as a solvent. it can.

The use of such calcium- and / or sodium-containing powder as an adsorbent and the introduction of calcium- and / or sodium-containing powder into the exhaust gas through the device 9 as described above comprises the calcium-containing and / or sodium-containing powder. And / or the sodium-containing powder secures a large surface area for reacting with sulfur oxides contained in the exhaust gas of the internal combustion engine 1, that is, with SO ₂ and SO _3. It can be effectively converted to calcium CaSO ₄ and / or sodium sulfate Na ₂ SO ₄ . The reaction of calcium- and / or sodium-containing powders with SO ₂ and SO ₃ is typically effected according to the following reaction formula: That is, Ca (OH) ₂ follows the following reaction formula.
Ca (OH) ₂ + SO ₂ ⇔CaSO ₃ + H ₂ O
Ca (OH) ₂ + SO ₂ + ／ O ₂ ⇔CaSO ₄ + H ₂ O
Ca (OH) ₂ + CO ₂ ⇔CaCO ₃ + H ₂ O
Ca (OH) ₂ + SO ₃ ⇔CaCO ₄ + H ₂ O
For CaCO ₃ , the following reaction equation follows.
CaCO ₃ + SO ₂ ⇔CaSO ₃ + CO ₂
CaCO ₃ + SO ₂ + ／ O ₂ ⇔CaSO ₄ + CO ₂
CaCO ₃ + SO ₃ ⇔CaSO ₄ + CO ₂
For NaHCO ₃ , the following reaction equation follows.
2NaHCO ₃ → Na ₂ CO ₃ + CO ₂ + H ₂ O
Na ₂ CO ₃ + SO ₂ + 1 / 2O ₂ → Na ₂ SO ₄ + CO ₂
Na ₂ CO ₃ + SO ₃ → Na ₂ SO ₄ + CO ₂

By introducing the calcium- and / or sodium-containing powder into the exhaust gas via the device 9 upstream of the separator 3, the powdered calcium sulfate CaSO ₄ and / or sodium sulfate Na ₂ SO ₄ is formed and moved It can be discharged with the granules of the separator 3 formed as a bed reactor or a fluidized bed reactor.

  The separator 3 has a relatively large particle size, ie a particle size of more than 2 mm, preferably more than 3 mm, as compared to calcium- and / or sodium-containing powder introduced into the exhaust gas through the device 9. Granules having a particle size, most preferably greater than 4 mm, are used.

The granules of the separator 3 contain calcium but not sodium. Therefore, the granules of the separator 3 do not contain any NaHCO ₃ . At best, NaHCO ₃ can be introduced into the exhaust gas as a relatively fine-grained powder through a device 9 upstream of the separator 3.

  The separator 3 preferentially receives calcium sulphate, which is captured via the granules and discharged together with the granules from the separator 3 designed as a moving bed reactor or a fluidized bed reactor, in a moving bed or in a fluidized bed. In order to separate from the granules on the floor, a device not shown is provided. The device can be, for example, a drum peeler, drum screen, or crusher. Following this, the granules depleted of calcium sulphate are fed back to a moving bed reactor or a fluidized bed reactor to form a granulate circuit and to make effective use of the granules. obtain.

A further exemplary embodiment of an exhaust gas aftertreatment system 2 arranged downstream of the internal combustion engine 1 is shown in FIG. 4, which is an example of the exemplary embodiment of FIGS. 2 and 3. Assemblies are combined. Thus, the exhaust gas aftertreatment system 2 of FIG. 4 introduces, on the one hand, an oxidation catalytic converter 8 for oxidizing SO ₂ to SO ₃ and, on the other hand, calcium- and / or sodium-containing powder into the exhaust gas. And a device 9. According to FIG. 4, the device 9 is located downstream of the oxidation catalytic converter 8, through which calcium- and / or sodium-containing powder can be introduced into the exhaust gas. Thus, the oxidation catalytic converter 8 is located downstream of the heating device 5 and the device 9 is located downstream of the oxidation catalytic converter 8 and upstream of the separator 3.

A further exemplary embodiment of an exhaust gas aftertreatment system 2 for an internal combustion engine is illustrated by FIG. 5, wherein the exhaust gas aftertreatment system 2 of FIG. The apparatus 10 includes a catalytic converter 8 and further includes an apparatus 10 for introducing gaseous ammonia (NH ₃ ) into exhaust gas. The apparatus 10 for introducing gaseous NH ₃ into exhaust gas is provided. , Is arranged downstream of the oxidation catalytic converter 8, so that NH ₃ is introduced into the exhaust gas of the internal combustion engine 1 upstream of the oxidation catalytic converter 8.

Here, NH ₃ itself may be directly introduced into the exhaust gas stream in a gaseous form, or an NH ₃ precursor such as urea may be injected into the exhaust gas stream, and the NH ₃ precursor may be injected into the exhaust gas stream. Evaporating the material to NH ₃ may be provided. The introduction of gaseous NH ₃ into the exhaust gas stream upstream of the oxidation catalytic converter 8 has the advantage that the ensuing denitrification of the exhaust gas can improve the subsequent desulfurization.

  In the exhaust gas aftertreatment system 2 shown in FIGS. 1 to 5, a multistage separator 3 designed as a moving bed reactor or a fluidized bed reactor improves the separation of calcium sulfate and, where appropriate, sodium sulfate. In particular, where a multi-stage separator 3 is used, granules of different particle sizes are used in individual stages of the separator 3. Thus, in the individual stages of the separator 3, the particle size of the granules is different from each other. Preference is given to using a separator 3 designed as a cross-flow separator.

The present invention may be used in an exhaust gas supercharged internal combustion engine having an exhaust gas turbocharger. Thus, in such a case, it is preferentially provided that at least the particle separator 3 is located downstream of the turbine of the exhaust gas turbocharger, not shown. If appropriate, the oxidation catalytic converter 8 preferentially employs such a converter, since the high pressure upstream of the turbine and the high temperature of the exhaust stream favor the oxidation of SO ₂ to SO ₃ in the oxidation catalytic converter 8. Located upstream of the turbine.

  The invention proposes an exhaust gas aftertreatment system for an internal combustion engine and a method for exhaust gas aftertreatment of exhaust gas leaving the internal combustion engine, wherein the desulfurization of the exhaust gas comprises a separation comprising calcium-containing particulates. This is performed in the vessel 3.

  In order to carry out this desulfurization in the separator 3 under optimal operating conditions, the exhaust gas leaving the internal combustion engine 1 has a process temperature upstream of the separator 3, preferentially between 400 ° C. and 450 ° C. , Ie, in multiple stages, heated first in the gas-gas heat exchanger 4 and then in the heating device 5. The gas-gas heat exchanger 4 utilizes the heat energy received at the separator 3 during the desulfurization to heat the exhaust gas leaving the internal combustion engine 1 to an intermediate temperature, and consequently the heating device 5, the heat output can be reduced. The heating device 5 can be an electrically operated heating device or, specifically, a combustor operated with a gaseous or liquid fuel, such as heavy oil.

  As already explained above, the chemisorption of sulfur oxides on the calcium-containing or lime-based granules of the separator 3 has been embodied as a packed bed reactor or as a moving bed reactor. Occur in the separator 3 containing the calcium-containing granules, the reaction being exothermic and thus releasing thermal energy. Separator 3 can be embodied with double walls to reduce heat loss in separator 3. Thus, the separator 3 can better utilize the heat energy released by the exothermic reaction for heating the exhaust gas leaving the internal combustion engine with the gas-gas heat exchanger.

  Optional use of the SCR catalytic converter 6 downstream of the separator 3 allows for denitrification of the exhaust gas, in particular urea as an ammonia precursor is downstream of the separator 3 and upstream of the SCR catalytic converter 6 Due to the high temperature downstream of the particle separator 3 when introduced into the exhaust gas at, a short evaporation distance for urea is appropriate. Due to the fact that already denitrified exhaust gases are led through the SCR catalytic converter 6, there is no risk of clogging the SCR catalytic converter 6.

In all the illustrated embodiments, an optional waste heat recovery device 7 is located downstream of the gas-gas heat exchanger 4. This can be, for example, a steam turbine in which residual heat of the exhaust gas is used to generate power. Due to the desulfurization of the exhaust gas carried out earlier, there is no danger that the corrosion due to the falling H ₂ SO ₄ will grow in the area of the exhaust heat recovery device 7.

  As mentioned above, the exhaust gas aftertreatment system 2 according to the invention is characterized by an optimally adapted temperature control. The exhaust gas leaving the internal combustion engine 1 typically has a temperature of less than 320 ° C. The temperature of the exhaust gas leaving the internal combustion engine 1 can be increased to some extent by interference in the internal combustion engine 1 on the engine side, for example by restricting the affected exhaust gas or by a wastegate. Exhaust gas leaving the internal combustion engine 1 can be heated through the gas-gas heat exchanger 4 to a temperature of approximately 350 ° C. In the area of the heating device 5, the exhaust gas is preferentially up to a temperature between 360 ° C. and 450 ° C. in order to provide an optimum process temperature for the chemisorption of sulfur oxides in the separator 3. Subsequently, it is heated. This chemisorption at the separator 3 is an exothermic reaction and the exhaust gas leaving the separator 3 has a higher temperature. This increased temperature of the exhaust gas already led through the separator 3 is used in the gas-gas heat exchanger 4. The SCR catalytic converter 6, which is optionally present and is located between the separator 3 and the gas-gas heat exchanger 4 in the exemplary embodiment shown, causes only a small reduction in the temperature of the exhaust gas. Downstream of the gas-gas heat exchanger 4, the residual heat of the exhaust gas is advantageously used in an exhaust gas aftertreatment device 7 for generating electrical energy. The temperature downstream of the exhaust heat recovery device 7 is approximately 120 ° C. at the maximum.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Exhaust gas aftertreatment system 3 Separator 4 Gas-gas heat exchanger 5 Heating device 6 SCR catalytic converter 7 Exhaust heat recovery device, exhaust gas aftertreatment device 8 Oxidation catalytic converter 9 Device 10 Device

Claims (13)

An exhaust gas aftertreatment system (2) for an internal combustion engine,
A separator (3) disposed downstream of the internal combustion engine (1) and containing calcium-containing particulates for chemisorbing sulfur oxides;
A gas-gas heat exchanger, wherein the exhaust gas guided through the separator (3) is used to increase the temperature of the exhaust gas leaving the internal combustion engine (1). A gas-gas heat exchanger (4), which is conducted through a gas heat exchanger, while the exhaust gas leaving the internal combustion engine (1) passes therethrough.
Downstream of the gas-gas heat exchanger (4) and upstream of the separator (3) to further increase the temperature of the exhaust gas led through the gas-gas heat exchanger (4). An exhaust gas aftertreatment system comprising a heating device (5) arranged. The heating device (5), the exhaust gas, characterized by heating in a warm Doma between 375 ° C. and 450 ° C., an exhaust gas aftertreatment system according to claim 1. The gas - gas heat exchanger (4), the exhaust gas, characterized by heating in a warm Doma between 330 ° C. and 350 ° C., the exhaust gas after-treatment according to claim 1 or 2 system.   Downstream of the separator (3) is located an SCR catalytic converter (6), the exhaust gas leaving the separator (3) being first guided through the SCR catalytic converter (6), 4. The exhaust gas aftertreatment system according to claim 1, wherein the exhaust gas aftertreatment system can be guided via the gas-gas heat exchanger. 4. An SCR catalytic converter (6) is located upstream of the gas-gas heat exchanger (4), and the exhaust gas leaving the separator (3) is first guided through the SCR catalytic converter (6). 4. The exhaust gas aftertreatment system according to claim 1, wherein the exhaust gas aftertreatment system is capable of being guided through the gas-gas heat exchanger .   The exhaust gas aftertreatment system according to any one of the preceding claims, characterized in that an exhaust gas aftertreatment device (7) is located downstream of the gas-gas heat exchanger (4). Upstream of the heating device the separator downstream of (5) (3), oxidation catalyst (8) is positioned to oxidize the SO ₂ to SO _3, through the oxidation catalytic converter (8) 7. The exhaust gas according to claim 1, wherein the exhaust gas heated in the heating device (5) can be guided upstream of the separator (3). 8. Processing system.   A device (9) is located downstream of the heating device (5) and upstream of the separator (3), through which the calcium- and / or sodium-containing powder is passed through the separator (3). The exhaust gas aftertreatment system according to any of the preceding claims, characterized in that it can be introduced into the exhaust gas heated by the heating device (5) upstream of 3). Device through as powders of the calcium-containing and / or sodium-containing can be introduced into the exhaust gas (9), the separator SO ₂ downstream of the oxidation catalytic converter (8) for the oxidation to SO ₃ The exhaust gas aftertreatment system according to claim 7, wherein the exhaust gas aftertreatment system is positioned upstream of (3). The device (9) powder of the said calcium being introduced into the flow of exhaust gases containing and / or sodium-containing through is, the CaO and / or Ca _{(OH) 2} and / or CaCO ₃ and / or NaHCO ₃ wherein, the particle size of the calcium-containing and / or sodium-containing powder is introduced into the device (9) through flow of the exhaust gas, characterized in that a 1mm less than, claim 8 or An exhaust gas aftertreatment system according to claim 9. As packed bed reactor, or, granules of a preferentially designed as a moving bed reactor wherein the separator (3) comprises CaO and / or Ca _{(OH) 2} and / or CaCO _3, wherein the separator The exhaust gas post-processing system according to any one of claims 1 to 10, wherein the particle size of the granular material (3) is more than 2 mm. A method for exhaust gas aftertreatment of exhaust gas leaving an internal combustion engine, comprising:
The exhaust gas is directed through a separator containing calcium-containing particulates for chemisorbing sulfur oxides;
In order to raise the temperature of the exhaust gas leaving the internal combustion engine, the exhaust gas guided through the separator and, on the other hand, the exhaust gas leaving the internal combustion engine are gas-gas Led through a heat exchanger,
The exhaust gas heated by the gas-gas heat exchanger is passed through a heating device located downstream of the gas-gas heat exchanger and upstream of the separator to further increase the temperature. How to be.   13. The method according to claim 12, characterized in that it is likewise implemented with an exhaust gas aftertreatment system according to any of the preceding claims.

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