DE102019130183A1 - Catalytic converter, exhaust aftertreatment system and internal combustion engine - Google Patents

Abstract

Catalytic converter (10) for an exhaust gas aftertreatment system of an internal combustion engine, in particular an SCR catalytic converter for an SCR exhaust gas aftertreatment system, with a catalytic converter housing (11), with a plurality of exhaust gas in a first direction (X1) accommodated in a first housing section (12) of the catalytic converter housing (11) through which honeycomb bodies (15) can flow, with a second housing section of the catalytic converter housing (11) which forms an inflow housing section (13) and through which exhaust gas can flow in a second direction (X2) in order to supply exhaust gas to the honeycomb body (15), with an outflow housing section (14) ) forming the third housing section of the catalytic converter housing (11) through which exhaust gas can flow in a third direction (X3) in order to discharge exhaust gas from the honeycomb bodies (15), the second direction (X2) running perpendicular to the first direction (X1), and wherein the third direction (X3) is perpendicular or parallel to the first direction (X1).

Description

The invention relates to a catalytic converter for an exhaust gas aftertreatment system of an internal combustion engine. The invention also relates to an exhaust gas aftertreatment system with a catalytic converter and an internal combustion engine with an exhaust gas aftertreatment system.

In combustion processes in stationary internal combustion engines, which are used, for example, in power plants, as well as in combustion processes in non-stationary internal combustion engines, which are used, for example, on ships, nitrogen oxides are formed, these nitrogen oxides typically being produced during the combustion of fuels such as coal, hard coal, lignite , Crude oil, heavy oil, diesel fuels or gases are produced. Such internal combustion engines are therefore assigned exhaust gas aftertreatment systems which serve to clean, in particular denitrify, the exhaust gas leaving the internal combustion engine.

To reduce nitrogen oxides in the exhaust gas, exhaust gas aftertreatment systems known from practice use catalytic converters, primarily so-called SCR catalytic converters. A selective catalytic reduction of nitrogen oxides takes place in an SCR catalytic converter, whereby ammonia (NH ₃ ) is required as a reducing agent for the reduction of the nitrogen oxides. For this purpose, the ammonia or an ammonia precursor substance, such as urea, is introduced into the exhaust gas in liquid form upstream of the SCR catalytic converter, the ammonia or the ammonia precursor substance being mixed with the exhaust gas upstream of the SCR catalytic converter. For this purpose, according to practice, mixing sections are provided between the introduction of the ammonia or the ammonia precursor substance and the SCR catalytic converter.

Although catalytic converters and exhaust gas aftertreatment systems known from practice that include a catalytic converter can already successfully be used for exhaust gas aftertreatment, in particular a reduction in nitrogen oxides, there is a need to further improve the catalytic converters and exhaust gas aftertreatment systems. In particular, there is a need for a compact design of such catalytic converters and exhaust gas aftertreatment systems.

Proceeding from this, the present invention is based on the object of creating a novel catalytic converter, a novel exhaust gas aftertreatment system of an internal combustion engine and an internal combustion engine with such an exhaust gas aftertreatment system.

This object is achieved by a catalytic converter for an exhaust gas aftertreatment system of an internal combustion engine according to claim 1.

The catalyst according to the invention has a catalyst housing. A plurality of honeycomb bodies through which exhaust gas can flow in a first direction are accommodated in a first housing section of the catalytic converter housing. Exhaust gas can be fed to the honeycomb bodies via a second housing section of the catalytic converter housing, which forms an inflow housing section and through which exhaust gas can flow in a second direction. Exhaust gas can be discharged from the honeycomb bodies via a third housing section of the catalytic converter housing, which forms an outflow housing section and through which exhaust gas can flow in a third direction. The second direction is perpendicular to the first direction. The third direction is also perpendicular or parallel to the first direction.

With a catalytic converter constructed in this way, effective exhaust gas aftertreatment can be guaranteed with a compact design.

According to an advantageous development, exhaust gas can flow through the honeycomb bodies in a vertical first direction from bottom to top, the inflow housing section and the outflow housing section both being able to flow through the exhaust gas in the horizontal second and third direction, wherein the outflow housing can also be flowed through vertically in the third direction. This is preferred in order to integrate the catalytic converter into the same with a compact design and at the same time ensuring effective exhaust gas aftertreatment in tight installation spaces, for example on a ship.

According to an advantageous development, a perforated tube is arranged in the inflow housing section, through which exhaust gas can flow in the second direction. This can further increase the effectiveness of the exhaust gas aftertreatment. The exhaust gas can be evenly distributed in the second housing section, i.e. in the inflow housing section, via the perforated pipe, the perforation of which can be flowed through from the inside to the outside, in order to ultimately evenly apply exhaust gas to all honeycombs and thus carry out the exhaust gas aftertreatment as effectively as possible.

According to an advantageous development, the inflow housing section and / or the outflow housing section can be rotated relative to the first housing section in such a way that when the second direction is perpendicular and the third direction is perpendicular or parallel to the first direction, the second direction and the third direction are either run parallel or perpendicular to each other. This refinement is preferred in order, depending on the structural shape of the internal combustion engine, to install the catalytic converter with little space requirement and compact dimensions in the space available.

The exhaust gas aftertreatment system according to the invention is defined in claim 10.

The internal combustion engine according to the invention is defined in claim 11.

• 1: eine schematisierte, perspektivische Ansicht eines erfindungsgemäßen Katalysators;
• 2: einen Querschnitt durch den Katalysator der 1;
• 3: einen Querschnitt durch Teile des Katalysators 1 in perspektivischer Ansicht.

Preferred developments of the invention emerge from the subclaims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being restricted thereto. It shows:

• 1 : a schematic, perspective view of a catalytic converter according to the invention;
• 2 : a cross section through the catalyst of the 1 ;
• 3rd : a cross section through parts of the catalytic converter 1 in perspective view.

The invention relates to a catalytic converter for an exhaust gas aftertreatment system of an internal combustion engine. The catalytic converter is preferably an SCR catalytic converter or oxidation catalytic converter for an SCR exhaust gas aftertreatment system.

1 to 3rd show schematically details of a catalyst according to the invention 10 holding a catalytic converter housing 11 includes. The catalytic converter housing 11 is basically in three housing sections 12th , 13th and 14th subdivided, wherein in a first housing section 12th of the catalytic converter housing 11 several honeycombs 15th with the formation of an array of honeycomb bodies 15th are arranged with several rows and columns. The housing section 12th can in turn consist of several layers of arrays made of honeycomb bodies. The honeycomb body 15th exhaust gas can flow through in a first direction X1.

The honeycomb body 15th have a flow cross-section with a rectangular cross-section between an inlet end and an outlet end of the respective honeycomb body 15th , each honeycomb body 15th is preferably surrounded on the outside by a metallic honeycomb body in sections, namely and leaving free the inlet end and the outlet end of the respective honeycomb body 15th .

The metallic honeycomb housings are also referred to as canning.

The catalytic converter housing 11 also has the second housing section 13th , which forms an inflow housing section, this inflow housing section 13th exhaust gas can flow through in a second direction X2 in order to reduce exhaust gas in the first housing section 12th positioned honeycomb bodies 15th to feed. The second housing section 13th , which provides the inflow housing section, is on one side of the first housing section 12th positioned, being on an opposite side of the first housing section 12th a third housing section 14th of the catalytic converter housing 11 is arranged, which provides an outflow housing section of the catalyst housing. The discharge housing section 14th exhaust gas can flow through in a third direction X3 in order to remove the exhaust gas from the honeycomb bodies 15th from the catalytic converter housing 11 discharge out.

The honeycomb body 15th that are in the first housing section 12th of the catalytic converter housing 11 are positioned are in accordance with 1 to 3rd Exhaust gas can flow through in a vertical first direction X1 from bottom to top. Below the first housing section 12th is the second housing section serving as the inflow housing section 13th positioned through which exhaust gas can flow in the second horizontal direction X2. Above the first housing section 12th is the third housing section serving as the outflow housing section 14th arranged, through which exhaust gas can flow in the horizontal or vertical third direction X3.

The housing sections arranged one above the other 12th , 13th and 14th are open on mutually adjacent sides to allow the exhaust gas to pass from the inflow housing section 13th in the first housing section 12th and from the first housing section 12th in the discharge housing section 14th to enable.

In the second housing section or the inflow housing section 13th of the catalytic converter housing 11 a perforated tube protrudes 16 into it. The perforated pipe 16 has a perforation on its cylindrical outer wall 17th which is formed by several holes. Exhaust gas passing through the catalytic converter 10 is to be performed, initially flows through an interior of the perforated tube 16 in the second direction X2 and then passes through the holes of the perforation 17th through the cylindrical wall of the pipe 16 through into the outside of the tube 16 located part of the inflow housing section 13th into it.

The perforation 17th on the cylindrical wall of the pipe 16 is preferably in the axial direction and in the circumferential direction of the tube 16 evenly, in the axial direction and in the circumferential direction are accordingly the spacing and size of the holes perforation 17th equal. This allows the exhaust gas to flow evenly in the inflow housing section 13th are distributed and so evenly in the first housing section 12th positioned honeycomb body 15th are fed to all honeycomb bodies 15th to be evenly charged with exhaust gas. This is for particularly effective exhaust gas aftertreatment in the catalytic converter 10 advantageous.

As in 1 shown, has the second housing section or inflow housing section 13th Over a length I, which extends in the second direction X2, over a height h, which extends in the first direction X1, and over a width b. Length I, height h and width b define the volume of the inflow housing section 13th .

The perforated pipe 16 has a diameter d and extends within the inflow housing section 13th Over the entire length I of the inflow housing section 13th . The length I of the inflow housing section 13th and the diameter d of the pipe 16 define the volume of the perforated tube 16 within the inflow housing section 13th .

• Erstens beträgt ein Verhältnis zwischen einer freien Strömungsquerschnittsfläche der Perforation 17 des perforierten Rohrs 16 und einer Gesamtoberfläche des perforierten Rohrs 16, nämlich der zylindrischen, perforierten Wand desselben, zwischen 1:10 und 1:5. Siehe auch Anspruch 6.

To ensure that the exhaust gas is distributed as evenly as possible in the inflow housing section 13th to ensure and so ultimately all honeycomb bodies 15th Applying exhaust gas uniformly has been found to be particularly advantageous if at least one of the following four value ranges, preferably a combination of several or particularly preferably a combination of all, are used:

• First is a ratio between a free flow cross-sectional area of the perforation 17th of the perforated pipe 16 and a total surface area of the perforated tube 16 , namely the cylindrical, perforated wall of the same, between 1:10 and 1: 5. See also claim 6.

Second is a ratio between the volume of the inflow housing section 13th and the volume of the perforated tube 16 within the inflow housing section 13th between 6: 1 and 4: 1. See also claim 6.

Third, a ratio between the height of the inflow housing section is h 13th and the diameter d of the perforated tube 16 between 1: 1 and 1: 2. See also claim 6.

Fourthly, there is a ratio between the width b of the inflow housing section 13th and the diameter d of the perforated tube 16 between 2: 1 and 3: 1. See also claim 6.

The perforated pipe 16 is only open at one end, at an opposite end the same is from a wall of the inflow housing section 13th locked. The pipe points at the open end 16 an inflow opening 18th on.

Exhaust gas passing through the open end of the perforated pipe 16 or the inflow opening 18th flows into the same, is accordingly via the perforation 17th the cylindrical wall of the pipe 16 forced and occurs over the perforation 17th in the area of the inflow housing section 13th one that is outside the perforated tube 16 lies.

The discharge housing section 14th has an outflow opening on one side 19th to discharge the exhaust gas from the same.

As stated above, the inflow housing section 13th and the discharge housing section 14th to the first housing section 12th facing sides open, on the one hand, a passage of the exhaust gas from the inflow housing section 13th in the first housing section 12th and thus into the honeycomb body 15th and on the other hand, a passage from the honeycomb bodies 15th in the discharge housing section 15th to enable.

According to an advantageous embodiment of the invention, it is provided that the inflow housing section 13th and / or the outflow housing section 14th relative to the first housing section 12th , in which the honeycomb body 15th are arranged, is rotatable in such a way that when the second direction X2 and the third direction X3 are each perpendicular to the first direction X1, the second direction X2 and the third direction X3 are either parallel or perpendicular to each other. In doing so, the inflow opening can accordingly 18th of the perforated pipe 16 and thus the inflow housing section 13th and the discharge opening 19th of the discharge housing section 15th by turning the respective housing section 13th , 14th be relocated to a suitable position around the catalyst 10 to be connected to an exhaust gas aftertreatment system, namely to the exhaust-gas pipes of the same, in the best possible space. In this case, all housing sections then have 12th , 13th and 14th over a square base.

The invention is not only concerned with the catalyst 10 as such, but also an exhaust gas aftertreatment system with such a catalytic converter and an internal combustion engine, in particular an internal combustion engine operated with a diesel fuel, gas or heavy oil fuel, with such an exhaust gas aftertreatment system.

The invention is preferably used on ships and stationary power plants in connection with marine diesel internal combustion engines in which heavy oil, gas or residual oil is burned as fuel.

List of reference symbols

10

catalyst

11

Catalytic converter housing

12th

first housing section

13th

second housing section

14th

third housing section

15th

Honeycomb body

16

pipe

17th

perforation

18th

Inflow opening

19th

Discharge opening

Claims (11)

Catalytic converter (10) for an exhaust gas aftertreatment system of an internal combustion engine, in particular an SCR catalytic converter for an SCR exhaust gas aftertreatment system, with a catalytic converter housing (11), with a plurality of honeycomb bodies (15) accommodated in a first housing section (12) of the catalytic converter housing (11) and through which exhaust gas can flow in a first direction (X1), with a second housing section of the catalytic converter housing (11) which forms an inflow housing section (13) and through which exhaust gas can flow in a second direction (X2) in order to supply exhaust gas to the honeycomb body (15), with a third housing section of the catalytic converter housing (11) which forms an outflow housing section (14) and through which exhaust gas can flow in a third direction (X3) in order to discharge exhaust gas from the honeycomb bodies (15), wherein the second direction (X2) is perpendicular to the first direction (X1), and wherein the third direction (X3) is perpendicular to the first direction or parallel (X1). Catalyst after Claim 1 , characterized in that the honeycomb bodies (15) can be traversed by exhaust gas in a vertical first direction (X1) from bottom to top. Catalyst after Claim 1 or 2 , characterized in that the inflow housing section (13) and outflow housing section (14) can both be flowed through by exhaust gas in the horizontal second and third direction or vertically in the third direction (X2, X3). Catalyst after one of the Claims 1 to 3rd , characterized in that a perforated pipe (16) through which exhaust gas can flow in the second direction (X2) is arranged at least in sections in the inflow housing section (13). Catalyst after Claim 4 , characterized in that a perforation (17) of the perforated tube (16) is uniform in the axial direction and circumferential direction of the tube (16). Catalyst after Claim 4 or 5 , characterized in that, a ratio between a free flow cross-sectional area of the perforation (17) of the perforated tube (16) and a total surface area of the perforated tube (16) is between 1:10 and 1: 5, and / or a ratio between a volume of the inflow housing section (13) and a volume of the perforated tube (16) within the inflow housing section (13) is between 6: 1 and 4: 1, and / or a ratio between a height (h) of the inflow housing section (13) and a diameter ( d) of the perforated tube (16) is between 1: 1 and 2: 1, and / or a ratio between a width (b) of the inflow housing section (13) and a diameter (d) of the perforated tube (16) is between 2: 1 and is 3: 1. Catalyst after one of the Claims 1 to 6th , characterized in that the inflow housing section (13) and / or the outflow housing section (14) is rotatable relative to the first housing section (12) such that when the second direction (X2) and the third direction (X3) are each perpendicular to the first Direction (X1) run, the second direction (X2) and the third direction (X3) run either parallel or perpendicular to each other. Catalyst after Claim 7 , characterized in that a base area of the inflow housing section (13), outflow housing section (14) and first housing section (12) is each square. Catalyst after one of the Claims 1 to 8th , characterized in that the honeycomb bodies (15) have a flow cross-section of rectangular cross-section between an inlet end and an outlet end, each honeycomb body (15) preferably being partially surrounded on the outside by a metallic honeycomb body housing, leaving an inlet end and an outlet end free of the respective honeycomb body. Exhaust aftertreatment system of an internal combustion engine, in particular SCR Exhaust aftertreatment system, with one of the catalytic converters after one of the Claims 1 to 9 . Internal combustion engine (1), in particular an internal combustion engine operated with a diesel fuel, gas or with a heavy oil fuel, with an exhaust gas aftertreatment system Claim 10 .

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