WO2016135026A1

WO2016135026A1 - Molded part for treating a fluid

Info

Publication number: WO2016135026A1
Application number: PCT/EP2016/053402
Authority: WO
Inventors: Daniel WIDHALM
Original assignee: Dürr Systems GmbH
Priority date: 2015-02-26
Filing date: 2016-02-18
Publication date: 2016-09-01
Also published as: DE102015205552A1

Abstract

A molded part for treating a fluid, in particular for controlling the temperature of a fluid, which can, for example, be used to form a heated bed (24) of a regenerator (14) or in a wall-flow filter or catalytic converter, comprises a block (27) made of a heat-conducting material, defined by a base (X-Y) and a height extending perpendicular to the base, said block (27), when seen in the cross-section, having a plurality of cells (28) parallel to its base (X-Y). The block (27) has a plurality of channels (30, 32) extending substantially parallel to each other and to the direction of height (Z) of the block, each of said channels (30, 32) being provided in a cell (28) in such a manner that an inner wall (34) is present between the channels (30, 32) in adjacent cells (28). Furthermore, a cross-sectional shape of the channels (30, 32) or of the inner walls (34), parallel to the base (X-Y) of the block (27), has a structural length (s) of a section having a constant curvature sign of not more than 3.5 mm, or of not more than 20% of the total circumference of the cross-sectional shape of the channels.

Description

FORM BODY FOR TREATING A FLUID

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a molding for treating, in particular

Tempering a fluid. The present invention further relates to a heat exchanger with at least one heat bed, which has at least one such shaped body, a thermoreactor, in particular for the regenerative thermal oxidation of combustible substances in an exhaust or exhaust gas stream having at least one such heat exchanger as a regenerator, and also the use of the shaped bodies according to the invention in catalysts and filters.

TECHNICAL BACKGROUND

Thermoreactors, in particular those in plants for regenerative thermal

Oxidation (RTO) of combustible substances in a waste air or exhaust gas stream, typically have a combustion chamber acted upon by a gas stream to be thermally reacted and at least two regenerators, for example below the combustion chamber. In this case, one of the regenerators is preferably acted upon in a specific operating state of the thermoreactor with a (first) gas flow, which is supplied to the combustion chamber, while the other regenerator is acted upon by a (second) gas flow emerging from the combustion chamber. Usually, the first gas stream receives from the flow-through regenerator a certain amount of heat energy, while the second gas stream in turn receives heat energy to the associated

Regenerator gives off. For temporary storage of heat energy in

Regenerators in addition to heat-storing beds (such as balls, calipers, etc.) alternatively or additionally used thermal beds with, for example, ceramic moldings. These are characterized by a predictable and homogeneous pressure difference at a certain flow through the respective heat bed, as in the

Channels of the bricks usually forms a laminar flow of the passed through the regenerator fluid (gas or liquid) is formed.

The thermal efficiency and service life of the regenerators are important parameters for the efficient use of such regenerators. However, the thermal efficiency and the life are thereby by the formation of deposits within the regenerators with subsequent blockwise clogging of individual flow channels or entire blocks in the heat beds influenced (so-called "blocking"). This

"Blocking" occurs in particular by precipitation of solids from the fluid passed through, with certain solids settle on the channel walls and accumulate there. For example, in the purification of siloxane-containing flashings, the failure of Si oxides on the channel walls occurs.

The result of blockage of the regenerators is that the heat beds of affected RTO systems have to be freed from the deposits at regular intervals or the affected moldings of the heat beds have to be replaced. For this

Maintenance work, the RTO system must be shut down and cooled down before the shaped bodies of the heated beds can be cleaned or replaced. It usually takes 2 to 3 working days for the RTO system to become operational again.

During this time, the production area connected to the RTO plant will generally not be able to fully operate, so that the service life, i. The time it takes to lock the heated beds, a regenerator of an RTO system, can be a decisive factor for the efficiency and economy of the system.

The problem of blocking does not only exist with thermoreactors or their regenerators. The blocking of the flow channels can equally occur in other heat exchangers, filters, catalysts, etc. in a wide variety of applications and have corresponding disadvantages.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an improved molded article which obviates or at least mitigates the disadvantages of the prior art described above.

In particular, a molded article with improved resistance to blocking of its flow channels should be created.

This object is achieved by the teaching of the independent claims. Particularly preferred embodiments and further developments of the invention are specified in the dependent claims. According to a first aspect of the invention, a shaped body for treating a fluid comprises a block of thermally conductive material defined by a base and a height perpendicular to the base, the block having a plurality of cells in cross-section parallel to its base. Also formed in the block are a plurality of channels substantially parallel to each other and to the height direction of the block, each of these channels being provided in a cell such that there is an interior wall between the channels in adjacent rows. In addition, a cross-sectional shape of the channels or the inner walls parallel to the base of the block has a structure length of a portion of a constant curvature sign of at most 3.5 mm, preferably at most 2.85 mm, and / or at most 20%, preferably at most 15 %, of the total circumference of the cross-sectional shape of the channels. The curvature sign in this context includes the values convex, concave and rectilinear. The structure length of the cross-sectional shape of a channel is understood to be an edge length of the relevant n-edge in the case of an n-cornered channel. It has been found that a tendency to form deposits of solids precipitated from gaseous fluid flow at temperatures between 400 ° C and 1 .100 ° C increases greatly from a "critical structure length". Concretely, for a channel of hexagonal cross-sectional shape, the critical structure length with respect to deposition of silicon oxides is about 2.82 mm when the channel is traversed with a siloxane-containing exhaust gas at a speed between 1 m / s and 6.5 m / s. The viscosity of the exhaust gas can be between 15 pPa-s and 40 pPa-s. By limiting the structure length of the channel cross-section can generally a deposition of

(solids precipitated from the fluid flow at higher temperatures or entrained in the fluid flow for other reasons) on a channel wall. For gaseous fluids having a nitrogen content of more than 60% by volume, therefore, a limitation of the structure length of the cross-sectional shape of an n-cornered channel to 3.5 mm may be proposed.

The block of the shaped body is formed of a thermally conductive material. The thermally conductive material preferably has a thermal conductivity of at least about 1.5 W / mK, preferably at least about 2.0 W / mK or more. Besides, that has thermally conductive material preferably has a low coefficient of thermal expansion of at most about 1 -10 ^{~ 4} K ^{~ 1} , preferably of at most about 1 -10 ^{~ 5} K ^-1 , 8-10 ^'6 K ^-1 or less (each at 800 ° C). Further, the heat-conductive material preferably has a high specific heat capacity of at least about 500 J / kgK, preferably at least about 800 J / kgK or more. In addition, a preferred thermally conductive material has a softening temperature of at least about 1,000 ° C, more preferably at least about 1,200 ° C, even more preferably at least about 1,400 ° C. The thermally conductive material for the molded article is preferably selected from ceramics, brick, clay, metals, precious metals, silica, carbides, graphite or the like high-temperature-stable materials. Particularly preferred are ceramics with a proportion of more than 50% of silica and / or alumina.

In the context of the invention, a base area of the block is to be understood as meaning, in particular, a surface of the block that runs perpendicular to the height direction of the block, but also a flat projection surface, perpendicular to the height direction of the block, of a surface of the block. In this case, this surface of the block itself at least partially or partially cut, stepped and / or curved trained or executed. The block comprises a plurality of cells according to the invention. The cells are preferably unit cells, i. essentially identically designed and dimensioned cells. In addition, the block - in particular depending on the base surface shape of the block and cross-sectional shape of these cells - but also have other cells with different cross-sectional shapes. Such cells with other cross-sectional shapes may preferably be present in the edge region of the block. However, it may also be advantageous if the cells of the block have at least two unit cells of different configuration and / or dimensioning. Preferably, the different cells are each arranged in a "supercell" in a cell pattern, wherein the block may preferably be formed from a plurality of such supercells. In particular, a repeating arrangement of

Cells in a supercell or a block are understood.

The channels are preferably positioned substantially centrally in the individual cells. The block of the shaped body is preferably formed in one piece. Accordingly, the cells of the block are not formed by separate components, but are defined within the block as fictitious geometric shapes. In other embodiments of the invention, the cells may also be formed by individual cell bodies joined to the block.

In a preferred embodiment of the invention, the cross-sectional shape of the channels or of the inner walls has at least one convex section and at least one concave section. Particularly preferably, the cross-sectional shape of the channels or of the inner walls has a plurality of convex portions and a plurality of concave portions, which are provided alternately along the cross-sectional shape. The cross-sectional shape of the channels is preferably formed star-like or flower-like. The cross-sectional shape of a channel is preferably formed substantially point-symmetrical to the longitudinal axis of the channel.

In conventional heat storage moldings are already known with different channel geometries. Thus, the flow channels of the moldings of conventional heat exchangers have, for example, square, rectangular or circular cross-sectional shapes. These cross-sectional shapes have in common that they have a purely convex geometry in which direction changes between adjacent sections of the cross-sectional shape are always directed towards the center of the cross-sectional shape. It has been found that deposits of (from the fluid passing through the shaped body through or otherwise entrained in the fluid) solid particles on the channel walls of the moldings by providing concave

Sections in the cross-sectional shape of the channels or of convex sections in the

Cross-sectional shape of the inner walls can be effectively delayed or even suppressed.

The concave and convex portions are preferably provided distributed over the entire circumference of the channels. In the context of the invention, however, the concave and convex portions may also be provided only in partial areas of the cross-sectional shapes. In a preferred embodiment of the invention, the cross-sectional shape of the channels, starting from a basic shape alternately on several sections within the basic shape and a plurality of sections outside the basic form. The basic shape is preferably circular, but in the context of the invention may also be square, rectangular, hexagonal and the like regularly shaped. The basic form is in this

It is related to a fictional two-dimensional geometric shape used to define the cross-sectional shape of the channels perpendicular to the height direction of the channels.

Preferably, the cross-sectional shape of the channels is formed starting from the basic shape by periodic oscillations around the basic shape. At the periodic

Vibrations are preferably sinusoidal and / or cosinusoidal

Vibrations. In the context of the invention, however, other arcuate are

Vibrations, rectilinear vibrations (e.g., sawtooth patterns, double sawtooth patterns, etc.) as base vibrations or combinations of arcuate and rectilinear base vibrations are possible. The combinations may be formed at least in sections sequentially or overlapping / interfering from the respective base oscillations.

Preferably, an amplitude of the deviations, in particular the

Vibrations of the basic shape of at least about 5% and / or at most about 20%, preferably about 7.5% or about 10% with respect to the basic size of the basic shape (e.g., circle radius, edge length or half diagonal).

Preferably, a number of the vibrations around the basic shape are selected from 4, 6, 8 or 12.

Preferably, a distance between the basic shapes of adjacent channels is at least about 0.25 mm, preferably at least about 0.35 mm, and / or at most about 1.00 mm, preferably at most about 0.70 mm.

In another preferred embodiment of the invention, the channels each have a cross-sectional shape parallel to the base of the block in the form of a regular polygon. The cross-sectional shape of these channels is preferably in the shape of a triangle, Squares, pentagons, hexagons or octagons, with the hexagonal cross-sectional shape being particularly preferred.

In a further preferred embodiment of the invention, the cells each have a cross-sectional shape parallel to the base of the block in the form of a regular polygon. The cross-sectional shape of the cells in the form of regular polygons has the advantage that the cells can be arranged side by side with a small distance from each other, for example to build a thermal bed of a regenerator. In addition, the channels in the cells can be safely separated from one another in this cross-sectional shape of the cells.

In a further preferred embodiment of the invention, a hydraulic diameter of a channel is at least about 2.3 mm and / or at most about 5.0 mm. In the case of channels having a circular cross-sectional shape, the hydraulic diameter is essentially defined by the circular diameter of the cross-sectional shape, while in other channel geometries the hydraulic diameter is essentially defined by the diameter of a circle (in-circle diameter) inside the cross-sectional shape. In a further preferred embodiment of the invention, a quotient of a hydraulic diameter of a channel to a minimum wall thickness of the inner wall between adjacent channels is at most about 6.0, preferably at most about 5.5. Specifically, said ratio is between 4.1 and 5.9 using a material having a thermal conductivity between about 1.5 W / mK and

8.0 W / mK and a (mean) flow velocity of a gaseous fluid flow passing through the channels between 1 m / s and 6.5 m / s. The viscosity of the gaseous fluid flow can be between 20 pPa s and 40 Pa s. It has been found that in such a (preferably uniform) determination of the ratio between the hydraulic diameter of the channels and wall thickness of the channels in a molded body according to the invention an optimum can be achieved between the lowest possible mass of the block on the one hand and the greatest possible heat capacity. In yet another preferred embodiment of the invention, a hydraulic flow area of a channel is at least about 50% and / or at most about 65% with respect to a cross-sectional area of the cell. Such an interpretation also contributes to an optimization of the ratio between the smallest possible mass of the block and the largest possible heat absorption capacity. Specifically, said value is between 51% and 63% using a material having a thermal conductivity between about 1.5 W / mK and 8.0 W / mK and a (mean) flow velocity of one gaseous fluid flow passing through the channels between 1 m / s and 6.5 m / s. The viscosity of the gaseous fluid flow can be between 15 pPa s and 40 pPa s.

In yet another preferred embodiment of the invention, an open cross-sectional area of a channel is at least about 50% and / or at most about 75% with respect to a cross-sectional area of the cell.

In a further preferred embodiment of the invention, a minimum wall thickness of an inner wall between adjacent channels is at least about 0.20 mm and / or at most about 1.00 mm. Preferably, the wall thickness is configured in a value range between 0.25 mm and 0.89 mm. Particularly preferred individual values for a substantially uniform wall thickness of all channels are 0.23 mm, 0.25 mm, 0.48 mm, 0.56 mm and 0.81 mm. It has been found that with such a (preferably uniform) determination of the wall thickness of all channels at a

an optimum can be achieved between the lowest possible mass of the block on the one hand and the greatest possible heat capacity on the other. This is especially true when using a material with a thermal

Conductivity between about 1, 5 W / mK and 8.0 W / mK and a (mean) flow velocity of a gaseous fluid flow passing through the channels between 1 m / s and 6.5 m / s. In still another preferred embodiment of the invention, a Nusselt number of a laminar flow channel is dependent on that in the respective one

Use case through the channel flowing fluid is chosen so that it is at least about 3.5, preferably at least about 4.0, and / or at most about 4.5. The Nusselt number is defined as dimensionless size as a product of hydraulic diameter with the quotient of the heat transfer coefficient to the thermal conductivity coefficient. Such a design choice is particularly preferred with simultaneous execution of the block of a ceramic material with a proportion of more than 50% aluminum and / or silicon oxides. Such a design choice is particularly preferred with simultaneous execution of the block of a material for producing a block according to the invention, which has a thermal conductivity between about 1, 5 W / mK and 8 W / mK. Optionally, it can be provided that a correspondingly shaped molding is passed by a gaseous fluid flow with a (mean) flow velocity between 1 m / s and 6.5 m / s. The viscosity of the gaseous fluid flow can be between 15 pPa s and 40 pPa s.

In a preferred embodiment of the invention, the inner walls of the molding are at least partially porous. Shaped bodies of this type can be used in particular in filters, catalysts and the like in an advantageous manner.

In a further preferred embodiment of the invention are the channels

delimiting walls provided with a protective layer, for example in the form of a protective layer of nanoparticles. For the realization of a protective layer according to the invention, particles of silicon oxide, titanium dioxide, aluminum oxide, iron oxide, zinc oxide, silicon carbide, iron carbide, tungsten carbide, titanium nitride, boron nitride and boron carbide are proposed, the largest dimension of each being less than 100 nm. Such a "nano-protective layer" is produced According to the invention, a nano-scale rough surface on the inner walls of the channels, so that form microscopic vortexes on the channel surface. A deposition of (from the fluid flowing through the shaped body through or for other reasons carried in the fluid) solid particles is prevented or slowed down. In this way, a "blocking" of the channels can be effectively prevented. In preferred embodiments, the protective layer has a surface roughness Ra of less than 25 μm, in particular less than 10 μm, particularly preferably less than 2.5 μm. Preferably, the protective layer may be formed as a hydrophobic layer. In other applications, however, it may also be advantageous to make the protective layer hydrophilic. In another preferred embodiment of the invention, these are the channels

delimiting walls provided with a protective layer against damage by the flowing through the molding body fluid. Especially with fluids that may contain aggressive ingredients, components, etc., such protection of the walls bounding the channels is beneficial. Such shaped bodies can be used in particular in filters, catalysts and the like in an advantageous manner. These protective layers contain, for example, noble metals such as platinum, rhodium or palladium or non-noble metals such as copper, titanium, vanadium, zeolites. In the case of porous inner walls, such a protective layer may alternatively or additionally also be introduced into the interior spaces of the inner walls.

In yet another preferred embodiment of the invention, the walls bounding the channels are coated with a catalytically active material. In the case of porous inner walls, the catalytically active material is alternatively or additionally introduced into the interior spaces of the inner walls. Such configured moldings can be used in particular in catalysts in an advantageous manner.

According to a further aspect of the invention, a heat exchanger has at least one heat-bed, which has at least one shaped body of the invention described above.

In a preferred embodiment of the invention, the heat bed has a plurality of shaped bodies, which are arranged parallel to the base surface of the molded bodies next to one another and preferably without spacing from one another. In this way, it is possible to divide a fluid flow to be passed through to an arbitrarily expandable number of shaped bodies and thus to set the volume flow per shaped body and the corresponding flow rate. The preferred flow velocity is between 1 m / s and 6.5 m / s.

In a further preferred embodiment of the invention, the heat exchanger has at least two heat beds, which are arranged one above the other in the height direction of the molded bodies. The channels of the superimposed moldings are preferably substantially coaxial or aligned parallel to each other preferably identical cross-sectional shapes and / or preferably have the same

Dimensions. By superimposing heat beds, the heat absorption capacity of the heat exchanger can be adjusted. It has been found that with a number of 5 to 9 layers of similar heat beds an overall height of the heat exchanger from 1, 2 m to 3.5 m and a corresponding total length of through-flow channels can be achieved. Such a design choice is particularly preferred with simultaneous execution of a plurality of heat exchanger blocks of a ceramic material with a proportion of more than 50% aluminum and / or silicon oxides. Such a design choice is particularly preferred with simultaneous execution of the heat exchanger blocks of a material for producing a block according to the invention, which has a thermal conductivity between about 1, 5 W / mK and 8 W / mK. Optionally, it can be provided that a correspondingly shaped heat exchanger is passed by a gaseous fluid flow with a (mean) flow velocity between 1 m / s and 6.5 m / s. The viscosity of the gaseous fluid flow can be between 15 pPa s and 40 Ρθ-ε.

In a further preferred embodiment of the invention, a height of the

Heat beds in the height direction of the moldings at least about 20 cm, preferably at least about 25 cm, and / or at most about 50 cm, preferably at most about 40 cm.

In a still further preferred embodiment of the invention, a height of the heat exchanger in the height direction of the shaped body is at least about 100 cm, preferably at least about 150 cm, and / or at most about 300 cm, preferably at most about 200 cm.

According to another aspect of the invention, a thermoreactor comprises a combustion chamber and a regenerator, the regenerator being configured as a heat exchanger of the invention described above. The thermoreactor according to the invention can be used in particular in plants for the regenerative thermal oxidation of combustible substances in an exhaust air or exhaust gas flow in an advantageous manner. The channels of the moldings are preferably open to the combustion chamber, so that the fluid through the

Regenerators can flow into the combustion chamber or from the combustion chamber. In a preferred embodiment of the invention, a thermoreactor, in particular for the regenerative thermal oxidation of combustible substances in a waste air or exhaust gas flow, a combustion chamber and a regenerator, wherein the regenerator has at least one heat bed with at least one shaped body for tempering a fluid, the molded body a block of thermally conductive material defined by a base and a height perpendicular to the base, the block having in cross-section parallel to its base a plurality of cells, in which block a plurality of channels are formed which are substantially parallel extend to each other and to the height direction of the block, each of the channels is provided in a cell such that between the channels in adjacent cells, an inner wall is present, and a cross-sectional shape of the channels or the inner walls parallel to the base surface of the block a Strukturlä has a portion of a constant curvature sign of at most 3.5 mm, preferably of at most 2.85 mm, or of at most 20%, preferably of at most 15%, of the total circumference of the cross-sectional shape of the channels.

According to a further aspect of the invention, a thermoreactor has a combustion chamber and a regenerator, wherein the regenerator contains one or more shaped bodies according to the invention, which are in particular composed to a heat bed and flowed through by a particular substantially gaseous fluid flow, wherein the fluid flow of one or more having the following features:

average flow velocity between 1 m / s and 6.5 m / s,

Viscosity between 15 pPa-s and 40 Pa-s

- Temperature between 400 ° C and 1 .100 ° C

- Nitrogen content greater than 60 vol .-%.

According to yet another aspect of the invention, the molding of the invention described above can be used advantageously in a filter, in particular a wall-flow filter, or a catalyst, in particular a honeycomb catalyst. The resistance of the shaped body according to the invention to blocking of its flow channels is also advantageous in these applications. The filter or catalyst preferably has one or more such shaped bodies. BRIEF DESCRIPTION OF THE DRAWINGS

The above and other relevant features of the solutions according to the invention will become apparent from the following description of various concrete embodiments, for which the above-mentioned embodiments are also applied vice versa, with reference to the accompanying drawings. In it show, mostly schematically:

Fig. 1 is an illustration of a thermal reactor according to a first embodiment;

FIG. 2 is an illustration of a thermoreactor according to a second embodiment; FIG.

2A is an illustration of a thermal reactor according to a variant of the second

embodiment;

FIG. 2B shows an illustration of a thermoreactor according to a further variant of the second embodiment; FIG.

Fig. 3 is a plan view of a thermal bed for a thermal reactor of Fig. 1 or 2;

4 is an enlarged partial plan view of a shaped body of a heat bed of

Fig. 3 according to a first embodiment;

Fig. 5 is an enlarged partial plan view of a shaped body of a heat bed of

Fig. 3 according to a second embodiment; Fig. 6 is a plan view of several channels of a shaped body of Fig. 5 according to a

embodiment;

Fig. 7 is an enlarged plan view of a cell and a channel of Fig. 6; FIG. 8 is a plan view of a plurality of channels of a molded article of FIG. 5 according to another embodiment; FIG.

Fig. 9 is an enlarged plan view of a cell and a channel of Fig. 8; FIG. 10 is a plan view of a plurality of channels of a molded article of FIG. 5 according to another embodiment; FIG.

Fig. 11 is an enlarged plan view of a cell and a channel of Fig. 10;

Fig. 12 is a plan view of a plurality of channels of a shaped article of Fig. 5 according to yet another embodiment;

Fig. 13 is an enlarged plan view of a cell and a channel of Fig. 12;

FIG. 14 is a plan view of a plurality of channels of a molded article of FIG. 5 according to yet another embodiment; FIG.

Fig. 15 is an enlarged plan view of a cell and a channel of Fig. 14;

16 shows various further embodiments of possible cross-sectional shapes of channels of a molding of FIG. 5;

FIG. 17 is an enlarged partial plan view of a molded article of a heat bed of FIG.

3 according to a third embodiment; and

FIG. 18 is a sectional view of a multiple layer regenerator of thermal beds for a thermal reactor of FIG. 1 or 2. FIG.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

1 shows a thermoreactor 10, which can be used, for example, in a system for regenerative thermal oxidation (RTO) of a combustible material, in particular exhaust-gas or exhaust-gas stream containing volatile organic components (VOC), according to a first exemplary embodiment.

The thermoreactor 10 has a combustion chamber 12 and two regenerators 14 arranged below the combustion chamber 12. In the exemplary embodiment shown, the thermoreactor 10 has two regenerators 14, to each of which an antechamber 16 is assigned. In other embodiments, however, three, four or more may be used Regenerators 14 may be provided. Into the combustion chamber 12 protrudes a burner (not shown), are introduced via the liquid or gaseous fuel and optionally also combustion air into the combustion chamber 12. The burner is used for

Generation of a flame in the combustion chamber, which in turn allows ignition and combustion of the pollutants contained in the raw gas to be purified. The temperature in the combustion chamber 12 may in operation - u.a. depending on the energy content of the flammable substances contained in the raw gas - up to about 1,250 ° C.

The atria 16 of the regenerators 14 are each connected to a raw gas supply 18 and a clean gas discharge 20. The raw gas introduced via the raw gas feed 18 into an antechamber 16 is heated in the respective regenerator 14 before it is conducted into the combustion chamber 12. After a thermal conversion of the raw gas in the combustion chamber 12 is formed hot clean gas, which is cooled in the other regenerator 14 before it is discharged through the other pre-chamber 16 and the clean gas discharge 20 in an exhaust system. In a modified embodiment, the cooled clean gas stream may be fed to further heat exchange and / or purification stages before the clean gas is discharged into the environment or for further use. In the embodiment of Fig. 1, the thermoreactor 10 and its

Regenerators 14 flows alternately in opposite flow directions by switching the control valves 22a, 22b in the raw gas supply 18 and the clean gas discharge 29 at certain predetermined time intervals. For more detailed operation of such a thermoreactor, reference is made at this point by way of example to EP 1 312 861 B1.

2 shows a thermoreactor 10 according to a second exemplary embodiment, which can also be used, for example, in a system for the regenerative thermal oxidation (RTO) of a waste gas or exhaust gas stream containing combustible substances.

The thermoreactor 10 of FIG. 2 differs from the thermoreactor 10 of FIG. 1 by another type of flow control. As shown in Fig. 2, the raw gas supply 18 and the clean gas discharge 20 are each connected to a common rotary valve 23, which in turn with the antechambers 16 of both regenerators 14 is connected. By a rotation of the Rotationsventiis 23 of the thermoreactor 10 and its regenerators 14 are also flowed through in this case in certain predetermined time intervals alternately in opposite flow directions. FIG. 2A shows a variant of the embodiment of FIG. 2 according to the invention. In this exemplary embodiment, the thermoreactor 10 has a common regenerator construction 14, which is fluidically separated into two regions, so that the same functioning as in the exemplary embodiment of FIG. FIG. 2B shows a further variant of the exemplary embodiment of FIG

In this embodiment, the thermoreactor 10 'with its regenerators 14 is designed to be rotatable and connected via a common distribution valve 23' with the raw gas supply 18 and the clean gas discharge 20. Such a configuration is foreseeable especially for small thermoreactors 10 '.

In further variants of the invention, the embodiments of FIGS. 2A and 2B can also be combined with the embodiment of FIG.

For embodiments with a rotating thermoreactor 10 'are for the clean gas flow preferably an average flow rate between 0.6 m / s and 2.5 m / s and a burner side temperature between 700 ° C and 900 ° C and an outlet temperature between 40 ° and 150 ° C set. The viscosity of the clean gas flow can be between 15 pPa-s and 35 MPa s. For embodiments with a stationary thermoreactor 10, the clean gas flow preferably has an average flow velocity between 1 m / s and 6.5 m / s and a burner-side temperature between 800 ° C. and 1 .100 ° C. and an outlet-side temperature between 60 ° ° and 250 ° C set. The viscosity of the clean gas flow can be between 20 pPa s and 40 pPa s. The values mentioned can acquire particular significance in connection with the geometry of certain shaped bodies described below.

As indicated in FIGS. 1 and 2, the regenerators 14 of the thermoreactor 10 each have a plurality of heat beds 24 arranged one above the other. These warming beds 24 are each composed of a plurality of moldings 26, which are arranged perpendicular to the stacking direction of the heat beds (= height direction Z of the heat beds and the moldings) substantially without spacing side by side, as shown in Fig. 3. Preferably, the shaped bodies 26 of a heat bed 24 are designed and dimensioned substantially identical to one another.

Referring now to Figures 4 through 17, there will be described in more detail various preferred embodiments of a molded article 26 which may be used, for example, for the thermal beds 24 of the thermal reactors 10 of Figures 1 and 2.

The molded body 26 according to the first embodiment shown in Fig. 4 comprises a block 27 made of a ceramic material. Preferably, a hard ceramic with a proportion of more than 50% aluminum and / or silicon oxides can be used. Also are preferably ceramic materials having a thermal conductivity between about 1, 5 W / mK and 8 W / mK (preferably, for example about 2.1 W / mK), low thermal expansion coefficient of at most about 1 -10 ^{~ 5} ^~ K (preferably eg, about 6.5-10 ^" ^{6K _1} ) at 800 ° C, a high specific heat capacity of at least about 800 J / kgK (preferably, for example, about 910 J / kgK), and a high

Softening temperature of at least about 1, 000 ° C used for the block 27.

Optionally, other high temperature stable materials may be used for block 27.

The block 27 has, for example, a substantially rectangular or square base plane parallel to the X-Y plane (= drawing plane). As illustrated in Fig. 4, the block 27 is parallel to this base area X-Y divided into a plurality of unit cells 28, which have a hexagonal cross-sectional shape in this embodiment. The unit cells 28 directly adjoin one another. The cross-sectional shapes of the cells 28 in the form of regular polygons are particularly advantageous for the compact and substantially gap-free arrangement of the cells 28.

In each of the unit cells 28, a channel 30 is formed. The channels 30 extend substantially parallel to each other and substantially parallel to a height direction Z (perpendicular to the plane of the drawing of FIG. 4) of the block 27. The channels in this embodiment have a hexagonal cross-sectional shape and are each substantially one arranged centrally in the cells 28. As can be seen in FIG. 4, an inner wall 34 is present in each case between the channels 30 of adjacent cells 28. In addition, the block 27 is enclosed by an outer wall 36. Optionally, cells 28 'and channels 30' with other cross-sectional shapes can also be present in the edge area of the shaped body 26.

The edge length of the hexagon of the cross-sectional shape of the channels 30, which forms the structure length s in the sense of the invention, is preferably at most about 2.82 mm. At RTO-typical flow velocities of, for example, about 2.5 m / s, this limited structure length s is advantageous for slowing down or suppressing deposits on the channel walls.

Further, the channels 30 each define a hydraulic diameter Dh corresponding to the diameter of a circle inscribed in the hexagon in the hexagonal channels 30, and a hydraulic flow cross-sectional area Ah. For example, the hydraulic diameter Dh is about 2.90 mm or 4.85 mm, and the hydraulic flow sectional area Ah is about 60.8% or about 62.0% of the cross-sectional area of the cell 28. The inner walls 34 between the channels 30 adjacent cells 28 have a wall thickness t. The wall thickness t 'of the outer wall 36 is dimensioned larger than the wall thickness t of the inner wall. The wall thickness t of the inner walls 34 is for example about 0.56 mm or about 0.89 mm. Fig. 5 shows a shaped body 26 according to a second embodiment. The molded body 26 of the second embodiment differs from that of the first embodiment in the cross-sectional shapes of the channels 32.

In the second embodiment of FIG. 5, the unit cells 28 also have a hexagonal cross-sectional shape. However, the channels 32 have a cross-sectional shape based on a circular basic shape. That is, the cross-sectional shape of the channels 32 is not circular, but based only on this illustrated in Fig. 5, fictitious circular basic shape. It has been found that a resistance of the channels 32 against deposits from the exhaust air passed through it can be increased if the cross-sectional shape of the channels 32 is not formed solely convex, but has convex and concave portions.

With reference to FIGS. 6 to 16, the following is explained with reference to various exemplary embodiments of how the channel geometries based on the circular basic shape of FIG. 5 can be formed. In the embodiment of Figs. 6 and 7, the cross-sectional shape of the channels 32, starting from the circular base 38, has a total of six convex portions 38a and six concave portions 38b arranged alternately along the circumference. In another approach, the inner walls 34 between the adjacent channels 32 have cross-sectional shapes with alternating concave and convex portions.

The cross-sectional shape of the channels 32 in the embodiment of FIGS. 6 and 7 is formed from the circular basic shape 38 according to the following equation (1): η (φ) = ΚΙ * (ΐ + Ρ-8Ϊη (Ν-φ -π / 2)) ₍₁₎ with: Rl = radius of the base circle, 1, 45 mm

P = oscillation amplitude with respect to Rl, 10%

N = number of oscillations, 6

Dsep = distance between adjacent base circles, 0.55 mm

The radius r of the cross-sectional shape oscillates with six times the frequency and with an amplitude P of 10% of the nominal radius Rl, which is preferably selected between 1, 2 mm and 2.5 mm. Due to the sixfold oscillation frequency, the channels 32 can preferably be arranged analogously to a densest packing of circles in a hexagonal grid, wherein in this arrangement additionally the distance Dsep flows, which determines the minimum wall thickness t of the inner walls 34 between adjacent channels 32. As can be seen in Fig. 7, the hydraulic diameter Dh of the channels 32 is reduced compared to the circular cross-sectional shape. It is about 2.61 mm in this embodiment. In a modification (not shown) of this embodiment, for example, this disadvantage can be at least partially compensated for by reducing the parameter Dsep by increasing the nominal radius RI so that the radius oscillation has as a minimum the base circle 38 of FIG. 7 and thus the hydraulic diameter is about 2.90 mm.

The above-described radius oscillation can also be superimposed by one or more further oscillations.

Thus, the cross-sectional shape of the channels 32 in the embodiment of Figs. 8 and 9 is formed from the circular basic shape 38 according to the following equation (2): r _i (<p) = RI * (1 + P-sm (N - < p - K / 2) + P2 - sm (F - N - <p - DPHI - n / 2)) ₍₂₎ with: RI = 1, 45 mm, P = 10%, N = 6, Dsep = 0, 55 mm, P2 = 25% (secondary

Oscillation amplitude), F = 0.5 and DPHI = 3. The embodiment of Figs. 10 and 11 proceeds from that of Figs. 8 and 9 by a

Changing the parameters.

Thus, the cross-sectional shape of the channels 32 in the embodiment of FIGS. 10 and 11, starting from the circular basic shape 38, is also according to equation (2) above, but with RI = 1.45 mm, P = 10%, N = 6, Dsep = 0.4 mm, P2 = 25%, F = 2 and DPHI = 3 formed.

In addition to the above embodiments of Figures 6 to 11 with N = 6, other multiples of the angular frequency (e.g., N = 4, N = 8, or N = 12) may also be used to achieve a reduced deposit slope on the channel walls.

Thus, the cross-sectional shape of the channels 32 in the embodiment of FIGS. 12 and 13, starting from the circular basic shape 38, is also according to equation (2) above, but with R1 = 1, 45mm, P = 10%, N = 8, Dsep = 0.4mm, P2 = 15%, F = 2 and DPHI = 3.

Further, the cross-sectional shape of the channels 32 in the embodiment of Figs. 14 and 15 is based on the circular basic shape 38 according to the above equation (1) but with R1 = 1.45 mm, P = 7.5%, N = 12 and Dsep = 0.55 mm formed.

All of the above embodiments may be modified within the scope of the invention by using corresponding or similar cosine terms instead of the sine terms. Corresponding or similar cosine terms are used. For example, a development in a plurality of sine and / or cosine terms according to the following equation (3) is also conceivable:

r, {<p) = ^■ COS (, · φ - Δ φ _j (3)

e N: P _J , Q _J e [-l; l]; _ΛΓ; e δφ ^ Δ φ _} e [- π; π]

In all the above embodiments, the structure lengths s of the portions having a constant curvature sign, i. each of the convex portions 38a and the concave portions 38b of the cross-sectional shapes of the channels 32 is smaller than 2.85 mm.

In addition to the cross-sectional shapes of the channels 32 described above, of course, numerous other variants are conceivable within the scope of the present invention. Thus, FIG. 16 shows, by way of example, some further exemplary embodiments for star-like or flower-like cross-sectional shapes of the channels 32. In addition to the hexagonal cross sections of the unit cells 28 indicated in FIG. 16, other cross sections of unit cells 28 enveloping the respective channel 32, for example polygons [eg triangles, quadrilaterals , Pentagons, octagons, etc.], polygon-like geometries, etc., be advantageous, in particular if a preferably dense tiling of a base surface of the block 27 can be achieved by a corresponding cross-section of the unit cell 28. An enveloping cross-section of the unit cell 28 is understood to mean, in particular, an embodiment of the unit cell 28 with respect to the respective channel 32, in which one is located between the respective channels 32 of two adjacent ones Unit cell 27 resulting wall thickness does not fall below a value of 0.2 mm and / or of 1, 0 mm does not exceed. A preferred dense tiling is in particular a tiling of the base of the block 27 understood, in which the sum of the cross-sectional areas of all channels 27 in the base min. 50%, preferably min. 60%, more preferably min. 65% of the floor area of the block.

In a further modification of the invention, FIG. 17 shows a shaped body 26 with a block 27, in which cells 28 having a square cross-sectional shape are defined. The cross-sectional shapes of the channels 32 are based on a circular basic shape 38 and correspond, for example, to the above embodiments of FIGS. 6 to 16.

Finally, referring to Fig. 18, the construction of a multi-layer regenerator 14a-g of heat sinks 24 will be described in more detail.

The regenerator 14 is arranged in a reactor housing 40 of the thermoreactor 10 below the combustion chamber 12. The lower base of the regenerator 14 forms a grid 42 (e.g., metal or precious metal) on which optionally an expanded metal or expanded metal 44 is located.

On the grid 42 and the expanded metal 44, the plurality of layers a-g of heat beds 24 are arranged. Each thermal bed 24 is composed of a plurality of moldings 26. The heat beds 24 or shaped bodies 26 of the layers af each have a height h of, for example, about 30 cm, while the thermal bed 24 or the molded bodies 26 of the optional uppermost layer have a height h of, for example, only about 15 cm, so For the regenerator 14 a total height H of about 195 cm results in this embodiment. Between the heat beds 24 and the reactor housing 40, a so-called caliper body 46 of heat-storing bulk material is optionally also provided.

In this exemplary embodiment, the heat chains 24 of the layers ae are formed, for example, from 23 × 29 shaped bodies 26, and the heat beds 24 of the layers fg are formed, for example, from 21 × 27 shaped bodies 26. In this case, in the thermal beds 24 of the different layers ag either identical or different moldings 26, ie In particular moldings with cells 28 of the same or different cross-sectional shapes and / or channels 30, 32 of the same or different cross-sectional shapes are used. Furthermore, the heat chains 24 can also be partly formed from shaped bodies which do not correspond to the embodiments according to the invention. The advantages of the invention can also be achieved even if at least a part of the heat chains 24 of the regenerator 24 is configured according to the invention described above.

Further typical variants of regenerators 14 contain, by way of example, the following numbers of shaped bodies 26 in the X or Y direction and at layers of heat beds 24:

In the above embodiments, the molded article was used as an example of a regenerator of a thermal reactor. The invention is not limited to this application.

Thus, the above with reference to FIGS. 4 to 17 explained molding can be used in an advantageous manner, for example, in a wall-flow filter or a honeycomb catalyst. These can be used, for example, as diesel or soot particle filters in motor vehicles or other industrial applications (eg exhaust air purification, chemical process technology) are used. In particular, in industrial applications, it is preferable to arrange a plurality of moldings side by side and / or stacked on one another to provide larger fluid treatment units. In this case, the inner walls of the block forming the shaped body between the channels are preferably made porous, so that the fluid can flow through them and serve the inner walls as a filter. In this case, for example, a part of the channels is closed at the one end of the block, while the other part of the channels is closed at the other end of the block. Optionally, the inner walls can be covered with a protective layer, as well as fluids with aggressive ones

To be able to conduct components through the molded body. If the shaped body is to be used in a catalyst, the inner walls are preferably coated and / or filled with a catalytically active material.

REFERENCE NUMBER LIST

10 thermoreactor

10 'thermoreactor

12 combustion chamber

14 regenerator

16 antechamber

18 raw gas supply

20 clean gas discharge

22a control valve

22b control valve

23 rotary valve

23 'distribution valve

24 heat bed

26 moldings

27 block

28 cell, unit cell

28 'modified cell, border cell

30 channel (polygonal cross-sectional shape)

32 channel (circular cross-sectional basic shape) 34 inner wall

36 outer wall

38 basic form, preferably circular

38a convex section

38b concave section

40 reactor housing

42 grid

44 expanded metal

46 caliper body

Ah hydraulic flow cross-sectional area

Ao open flow cross-sectional area

Ie hydraulic diameter

Dsep distance of the base circles

h height of 24 and 26 respectively

H height of 14

N number of vibrations

P amplitude

Rl radius of the base circle

s structure length

t minimum wall thickness of the inner wall t 'wall thickness of the outer wall

X-Y base area

Z height direction

Claims

1 . Shaped body for treating, in particular tempering a fluid, comprising: a block (27) made of a thermally conductive material defined by a base (XY) and a height perpendicular to the base, the block (27) being in cross-section parallel to its base (XY) has a plurality of cells (28),

in the block (27) a plurality of channels (30, 32) is formed, which run parallel to each other and to the height direction (Z) of the block,

each of the channels (30, 32) is provided in a cell (28) such that an inner wall (34) is present between the channels (30, 32) in adjacent cells (28), and

a cross-sectional shape of the channels (30, 32) or the inner walls (34) parallel to the base (XY) of the block (27) has a structure length (s) of a portion of a constant curvature sign of at most 3.5 mm, preferably at most 2.85 mm , or of not more than 20%, preferably not more than 15%, of the total circumference of the cross-sectional shape of the channels.

2. Shaped body according to claim 1, wherein

the cross-sectional shape of the channels (32) or the inner walls (34) has at least one convex portion (38a) and at least one concave portion (38b).

3. Shaped body according to claim 1, wherein

the cross-sectional shape of the channels (32) or the inner walls (34) has a plurality of convex portions (38a) and a plurality of concave portions (38b) provided alternately along the cross-sectional shape.

4. Shaped body according to one of the preceding claims, wherein

the cross-sectional shape of the channels (32) starting from a basic shape (38), preferably a circular basic shape, alternately having a plurality of sections within the basic shape and a plurality of sections outside the basic shape.

5. Shaped body according to claim 4, wherein

the cross-sectional shape of the channels (32), starting from the basic shape (38), preferably a circular basic shape, is formed by periodic oscillations about the basic shape (38).

6. Shaped body according to claim 4 or 5, wherein

an amplitude (P) of the deviations from the basic shape (38) is at least about 5% or at most about 20%.

7. Shaped body according to one of claims 4 to 6, wherein

a number (N) of the vibrations around the basic shape (38) is selected from 4, 6, 8 or 12.

Shaped body according to one of claims 4 to 7, in which

a distance (Dsep) between the basic shapes (38) of adjacent channels (32) is at least about 0.25 mm, preferably at least about 0.35 mm, or at most about 1.00 mm, preferably at most about 0.70 mm.

A molded article according to claim 1, wherein

the channels (30) each have a cross-sectional shape parallel to the base (X-Y) of the block (27) in the form of a regular polygon.

Shaped body according to one of the preceding claims, in which

the cells (28) each have a cross-sectional shape parallel to the base surface (X-Y) of the

Blocks (27) in the form of a regular polygon.

Shaped body according to one of the preceding claims, in which

a hydraulic diameter (Dh) of a passage (30, 32) is at least about 2.3 mm or at most about 5.0 mm.

12. A molding according to any one of the preceding claims, wherein a hydraulic flow cross-sectional area (Ah) of a channel (30, 32) is at least about 50% or at most about 65% with respect to a cross-sectional area of the cell (28).

13. Shaped body according to one of the preceding claims, wherein

the walls (34, 36) delimiting the channels (30, 32) are provided with a protective layer.

14. Shaped body according to one of the preceding claims, wherein

the inner walls (34) are at least partially porous,

15. Shaped body according to claim 14, in which

the inner walls (34) and / or interiors of the inner walls (34) are provided with a catalytically active material.

16. A heat exchanger (14), comprising at least one heat bed (24), which has at least one shaped body (26) according to one of claims 1 to 13.

17. A heat exchanger according to claim 16, wherein

the heat bed (24) has a plurality of shaped bodies (26) which are arranged parallel to the base area (X-Y) of the shaped bodies next to one another, preferably without spacing from one another.

18. Heat exchanger according to claim 16 or 17, which

has at least two heat beds (24) which are arranged one above the other in the height direction (Z) of the shaped body (26). 19. Heat exchanger according to one of claims 16 to 18, wherein

a height (h) of the heat bed (24) in the height direction (Z) of the moldings (26) is at least about 20 cm, preferably at least about 25 cm, or at most about 50 cm, preferably at most about 40 cm.

20. Heat exchanger according to one of claims 16 to 19, wherein a height (H) of the heat exchanger (14) in the height direction (Z) of the shaped body (26) at least about 100 cm, preferably at least about 150 cm, or at most about 300 cm , preferably at most about 200 cm.

21. A thermal reactor (10), in particular for the regenerative thermal oxidation of combustible substances in a waste air or exhaust gas stream, comprising a combustion chamber (12) and a regenerator (14), wherein the regenerator (14) as a heat exchanger according to one of claims 16 to 20 is configured.

22. thermoreactor (10), in particular for the regenerative thermal oxidation of combustible substances in a waste air or exhaust gas stream, comprising a combustion chamber (12) and a regenerator (14), wherein the regenerator (14) one or more moldings (26) after a of claims 1 to 13, which are in particular to a heat bed (24) and flowed through by a particular substantially gaseous fluid flow, the fluid flow having one or more of the following characteristics: average flow velocity between 1 m / s and 6.5 m / s, viscosity between 15 pPa s and 40 MPa s,

Temperature between 400 ° C and 1100 ° C,

- Nitrogen content greater than 60 vol .-%.

23. Use of a shaped article according to one of claims 1 to 15 in a filter or catalyst,