WO2016026986A1

WO2016026986A1 - Pipeline for hot gases, and method for producing same

Info

Publication number: WO2016026986A1
Application number: PCT/EP2015/069378
Authority: WO
Inventors: Ralph Wenzel
Original assignee: Krones Ag
Priority date: 2014-08-22
Filing date: 2015-08-24
Publication date: 2016-02-25
Also published as: DE102014112053A1

Abstract

The invention relates to a pipeline device (1) for conducting fluid media, comprising a first outer tubular element (2), which is not permeable to the flowable medium and is suited and designed to maintain a pressure applied by the flowable medium, and a second tubular element (4), which is arranged within the first tubular element (2), is used to conduct the gaseous medium, and consists at least partly of a porous material. According to the invention, an insulating medium (12, 14) is arranged at least in some sections between the first tubular element (2) and the second tubular element (4), and the second tubular element (4) is made at least partly of a fiber-reinforced material which contains ceramic.

Description

Pipeline for hot gases and process for their production

description

The present invention relates to a pipeline, and more particularly to a pipeline for carrying hot flowable media, particularly hot gases. In addition, the invention relates to a method for producing such a pipeline Such pipelines are known from the prior art and are used for example in power plants, incinerators and the like. In these applications, it is often necessary to transport hot gases and / or hot liquids or vapors while still achieving satisfactory insulation. Numerous insulating concepts for gas conduction in high-temperature applications are known from the prior art. The longest-used systems are internally insulated bricked pipes with refractory and thermal insulating stones. The disadvantage here is mainly the problem of cracking in the lining due to temperature changes at e.g. Approach and departure. This poses a considerable risk for uses which are particularly sensitive to particle loadings in the gas stream, e.g. for the operation of turbines. Furthermore, in this concept, the installation of compensators proves difficult or it requires complex constructive measures to compensate for pipe stresses, e.g. in the form of lyra bows. Also, an increased maintenance through chipping and cracks in the lining is to be accepted.

A better alternative is to use internally insulated pipelines with a metallic Inliner made of Inconel or Hastelloy. However, the materials are often close to the Operated material load limit, so that in order to ensure the strength, high wall thicknesses are required, which is associated with high costs. Due to the required mounting of the inner tube to the outer tube there is a risk of thermal bridge formation. Also particularly disadvantageous proves to be the insufficient dimensional stability with fast pressure drop.

With the development of new materials and corresponding manufacturing methods insulating concepts have been developed that overrun the disadvantages of conventional concepts. Ceramics are distinguished, for example, by their excellent mechanical strength and strength even at high temperatures. They are extremely wear-resistant and show excellent sliding properties. They also have excellent heat resistance and are particularly resistant to acids and other chemical or chemo-electric attacks as well as to corrosion and can therefore be used in many areas.

Above all, internally insulated pipelines with ceramic inliner and pressure-retaining metallic outer pipe are known. However, no standard solutions are available. A challenge in this concept is the connection system between the ceramic pipes, which often requires complex constructions. In this case, there is a considerable risk that a gas flow occurs in the gaps between the transitions and between the inner insulation and the outer wall, in particular with larger pressure gradients in the flowing gas. These greatly reduce the insulating effect in a manner that is often uncontrollable, so that locally very high temperatures can occur. Furthermore, there is a considerable risk of cracking with high temperature differences between the flow space and the exterior.

EP 96791 A1 describes an insulation with inner non-pressure-tight tube for gas conduction made of a heat-resistant ceramic, an outer metallic pressure tube and a built-up of several bowls insulating layer of a mineral insulating material. To avoid gas flow into the insulation, additional sealing elements of mineral fibers are provided. DE3144857 describes a possibility to fix the ceramic inner tube coaxially, so that the relative position of the two tubes is maintained to each other. The present invention has for its object to provide insulation for pressurized and flowing at high flow rates gases at operating temperatures up to 1200 ° C. Another underlying object is to provide insulation which is stable to gas side pressure changes. Furthermore, a particularly abrasion-resistant insulation is to be presented by which no additional Staubund particle loads are introduced into the gas.

Areas of application of the invention are i.a. in gas ducts for nuclear power plants with gas-cooled high-temperature reactors, in hot blast lines for, for example, indirectly fired gas turbines, for solar thermal power plants or flue gas ducts of combustion chambers or furnaces.

The above objects are achieved by the subject matters of the independent claims. Advantageous embodiments and further developments are the subject matter of the subclaims.

A piping device according to the invention for conducting flowable media has an outer first tubular body which is impermeable to the flowable medium and is suitable and intended to withstand a pressure applied by the flowable medium. In addition, the pipeline device has a second tubular body arranged within the first tubular body, which serves to guide the gaseous and / or flowable medium and which at least partially consists of a porous material. According to the invention, an insulating medium is at least partially disposed between the first tubular body and the second tubular body, and the second tubular body is at least partially made of a fiber-reinforced and ceramic-containing material. An insulating medium is understood in particular to mean a medium which serves for thermal insulation.

Advantageously, the outer tubular body is made of a material and / or provided with a wall thickness which is suitable and intended to withstand the pressure applied by the flowable medium and this in particular also taking into account a high temperature of the flowable medium. Advantageously, the outer tube surrounds shaped bodies completely surround the inner tubular body in a direction surrounding a flow direction of the flowable medium. However, the piping means may be a branch piece such as a tee or a trouser piece. Preferably, the pipeline is designed such that it withstands temperatures of the flowable medium which are higher than 200 ° C, preferably higher than 400 ° C, preferably higher than 600 ° C, preferably higher than 800 ° C and preferably higher than 1000 ° C ,

The high brittleness proves to be disadvantageous in ceramic materials, which is critical even in safety-relevant applications in the high-temperature range. For this reason, it has been attempted to provide such materials with sufficient toughness. Such a possibility is ceramic fiber composites. Like classical ceramics, these have excellent high temperature mechanical properties, excellent heat resistance, and resistance to acids or other chemical or chemoelectrical attack and corrosion.

The ceramic fiber composite materials described here are advantageously made of ceramic fibers which are embedded in a - preferably also ceramic - matrix. Currently used fibers or fabrics are known, for example, under the brand name Nextel®.

According to the present invention, the underlying object is achieved such that the insulation is multi-layered and is preferably constructed with layers of various insulating materials and functions. The pipe insulation has an inner, preferably substantially non-pressure-tight, pipe with an erosion-resistant surface for guiding gas from a ceramic material or ceramic-containing material, but more preferably from an oxide-ceramic fiber composite material which is preferably constructed in individual segments, which are particularly preferably designed to be plugged together wherein the inner tube is at least partially porous. Furthermore, the insulation preferably has an outer metallic jacket which takes over the pressure inclusion. Between the gas guide tube and the pressure-bearing outer tube is advantageous at least one layer and are particularly advantageous various layers of insulating material attached, which consist of various materials or material combinations can exist and which are particularly preferably at least partially porous.

It is possible that the individual layers at least partially from prefabricated molded parts such. Shells, half-shells, pipe shells or casings exist. Preferably, the individual parts are laid in such a way that a leakage flow is avoided. For example, a staggered assembly is conceivable. It is possible that individual or multiple layers may be formed, for example, as a mat. Due to the predominantly porous structure and the staggered assembly, the risk of gas flows in the insulation composite is minimized, so that it can be used even with pressure cycling.

Advantageously, the piping device described here is used for conducting gases or vapors and in particular for conducting hot media. It would also be conceivable (if necessary, with further modifications, an application for conducting liquids.

In a further advantageous embodiment, the first tubular body is made of a metallic material. In this way, in particular a high pressure resistance can be achieved.

Advantageously, a porosity of the material of the second tubular body is between 10% and 40%, preferably between 25% and 35% and particularly preferably between 28% and 32%. The porosity is a dimensionless measurand and represents the ratio of void volume to total volume of a substance or mixture of substances. It serves as a classifying measure for the actually existing cavities.

In a further advantageous embodiment, a thickness of the second tubular body is between 1 mm and 15 mm, preferably between 1 mm and 10 mm and particularly preferably between 1 mm and 5 mm. Since the inner tube is not a pressure-bearing component, the design can be made according to other aspects.

In a further advantageous embodiment, the fiber content of the ceramic-containing material is arranged in a matrix. In a further advantageous embodiment, the fiber content of the ceramic-like material in the matrix is between 25% and 50%, more preferably between 30% and 45%, and most preferably between 35% and 40%.

In another advantageous embodiment, a material of the fibers of the fiber-reinforced material is selected from a group of materials comprising aluminum silicate fibers, mullite fibers, Al 2 O 3 fibers, SiO 2 fibers, Al 2 O 3 -SiO 2 fibers, SiC fibers, SiBNC fibers, SiCN fibers, Si 3 N ₄ fibers and ZrC> 2-fibers combinations thereof and the like. In addition, it is also advantageous to use Nextel fibers from 3M

The material of the matrix is preferably selected from a group of materials containing aluminasilicates, mullite, Al ₂ O ₃ , YSZ, SiO 2, SiC, Si ₃ N ₄ , ZrO ₂ and the system Al ₂ O ₃ -SiO ₂ -ZrO ₂ . In a particularly preferred embodiment, use is made of oxide-ceramic fiber composites which are advantageously based on continuous filament fabrics of the Al2O3-S1O2 system and a matrix of the Al203-SiO2-ZrC> 2 system, more preferably 3M ™ fibers with the Nextel ™ brand name 610 can be used. In a further advantageous embodiment, the second tubular body is segmented.

As mentioned above, in such pipes, the risk of cracking occur. So it would be conceivable that a plurality of nested tube segments are provided and / or a transition between these segments is step-shaped or cone-segment-shaped.

In a further advantageous embodiment, flat bodies are arranged on an outer circumference of the second tubular body, in particular fiber mats or other insulating materials. By flat bodies are understood body which extend in two mutually perpendicular directions in a predetermined length and in a direction perpendicular thereto in a much shorter length. Preferably, these are fiber mats of aluminum silicate and / or alumina. In this way, a flexible mounting of the second tubular body can be achieved. It is possible lend that these flat bodies are applied directly to an outer circumference of the second tubular body. Advantageously, a thickness of the layer resulting from these flat bodies is between 1 mm and 40 mm, preferably between 5 mm and 25 mm and particularly preferably between 5 mm and 15 mm.

As mentioned above, an insulating body, which can be formed, for example, from half-shells and / or specially cut and shaped plates, is preferably arranged around these flat bodies. Thus, for example, an insulation made of ceramic fiber molded parts can be provided here. For example, these could be vacuum-formed shark shell bodies. A thickness of this insulation may preferably be between 10 mm and 400 mm, preferably between 20 mm and 300 mm, preferably between 40 mm and 200 mm. The thicknesses given here are defined here in each case in a radial direction, i. in a direction which is perpendicular to a flow direction of the flowable medium. Between this insulating body and the outer tubular body, there may be another planar body, preferably of a ceramic-containing material, which in turn may completely surround the inner tubular body. This flat body preferably has a thickness of between 1 mm and 50 mm, preferably between 1 mm and 30 mm and particularly preferably between 1 mm and 15 mm.

In a further preferred embodiment, a further insulating element is arranged between the inner tubular body and the outer tubular body, and more preferably between the further planar body and the outer tubular body. This insulating element is preferably a microporous insulation. This microporous insulation can in this case again in shells such. be constructed like a shell. It would also be conceivable that two such insulating elements are arranged one above the other in the radial direction of the pipeline device. Preferably, at least one of these elements has a thickness which is between 10 mm and 300 mm, preferably between 20 mm and 200 m and particularly preferably between 20 mm and 100 mm.

Thus, in a particular embodiment, the inner gas guide tube, ie the second tubular body may be insulated with flexible fiber mats, fiberboard, wool, felt, fiber modules or other flexibly applicable insulating material, through which small movements. conditions of the inner tube can be accommodated, whereby a flexible storage is possible. In particular, high temperature resistant materials are used. In a further embodiment, these fiber mats can also be laid in a different position of the insulating composite.

Due to the multi-layered construction of the insulation, only the thermal expansion of the outer pipe in the pipeline network has to be compensated. Since the temperature of the jacket tube is advantageously at a very low level, can therefore be dispensed with complex compensation measures preferably.

Advantageously, the outer tube to prevent condensation can be additionally isolated outside.

The present invention is further directed to a cogeneration apparatus having at least one turbine and at least one piping device of the type described above. Preferably, the piping means is disposed in a flow direction of a medium to be supplied to the turbine upstream of the turbine.

The present invention is further directed to the use of a tubular body of the type described above for a cogeneration device.

The present invention is further directed to a method of manufacturing a piping device. In this case, an inner tubular body is provided in a first step. In a further optional method step, an attachment of insulating material, for example, of fiber mats to the inner tubular body takes place. Furthermore, a sealing material is applied around an outer periphery of this inner tubular body (in particular in the form of a jacket). Finally, the inner tubular body provided with the sealing material is mounted in an outer tubular body. Preferably, the outer tubular body is a pressure-resistant body, and more preferably a metallic body. In particular, the inner tubular body is a ceramic body containing a ceramic material. In a preferred method, the inner tubular body is centered. For this purpose, a centering aid (for example in the form of a centering platform) is particularly preferably used, and in particular a centering aid which consists of a softer material than the material of the tubular body or inner tube. For example, this centering aid can be made of wood or plastic.

Preferably, after the attachment of the fiber mats and / or after the attachment of the sealing material at least one and preferably a plurality of sealing strips is attached. In a further optional process step, the complete unit can be centered.

For the purpose of temporary fixing, a wrapping film and in particular a PE wrapping film may be applied. However, this winding film is preferably used only for the purpose of assembly. In a further preferred method, an insulating material is arranged in the outer tube and in particular glued. In a further preferred method, the assembly of the whole body takes place in a lying form.

In this case, initially a first layer of insulating material can be arranged on the outer tube or the first tubular body. It would also be conceivable that sealing strips are glued in the outer tube, in addition, other layers and sealing strips can be arranged on the outer tube. Finally, there is still a lowering of the outer tube to the inner tube.

The method described here can be applied both to rectilinear pipes and (if appropriate in slightly modified form and described in more detail below) to T-shaped pipes. Also, 90 ° bends or Y-pieces are possible.

Further advantages and embodiments will be apparent from the attached figures. 1 shows a cross section of an embodiment of the invention;

Fig. 2 shows the segmental construction of the gas guide tube;

Fig. 3 is a longitudinal section of an embodiment with mounting aids and Fig. 4 is a longitudinal section of a T-shaped embodiment with mounting aids.

Fig. 1 shows an illustration of a tubular body according to the invention. As shown in Fig. 1, according to the spirit of the invention, the gas flow is realized by means of an inner tube or an inner tubular body 4, which is not carried out pressure-tight. This is preferably a tube made of a ceramic-like or ceramic-containing material, preferably a tube made of a ceramic material, but more preferably an oxide-ceramic fiber composite material. Oxide ceramics are harder, more wear-resistant and heat-resistant, but also more brittle than hard metals. The advantages of these materials are their high hardness and heat resistance as well as their high chemical and thermal resistance. They are highly resistant to corrosion even at high temperatures in the operating range up to> 1000 ° C.

As a result, a tube for particularly high temperatures and a particularly elastic and thus also particularly temperature change resistant tube is created. To compensate for thermal expansion, the tube is advantageously divided into individual segments or pipe sections, which are particularly preferably plugged together or designed with connectors or sliding system. The transition between the sections may be formed stepwise and / or (preferably) as a cone segment. It is advantageous that in each case a pipe segment end protrudes over the entire length, so that it can be fitted into the inner tube of the next tube. Advantageously, the inner tube is a substantially porous tube.

Illustrated by the reference numeral 12 are advantageously existing high-temperature resistant fiber mats of aluminum silicate or aluminum oxide used in the prior art. These serve above all the mechanical damping and the protection of the external insulation against glazing and thermal radiation of the inner tube. Although the insulating effect is rather low, this expansions of the insulating composite are compensated and thus compensate movements or displacements of the gas guide tube with respect to the half-shells.

In this embodiment, the next layer 14 of vacuum-formed ceramic-based molded parts such as half shells or pipe shells, as these are well known in the prior art. Preference is given to moldings based on aluminum However, for the purposes of the invention, any type of high-temperature insulating materials can be used. Depending on the application, the molded parts can be laid in one or more layers, for example 2 or 3 layers, but preferably at least 2 layers. This allows a joint offset or staggered assembly and / or the use of sealing strips, which significantly reduces the risk of flowing through the insulation.

In addition, the maximum thickness of the molded parts is often limited in manufacturing by fading during firing, so that the desired total thickness for the necessary insulation effect can be achieved by using several superimposed shells. In the example of FIG. 1, a 2-layer insulation with ceramic fiber moldings 14 and a sealing strip 16 is shown. Furthermore, a centering of the inner tube is made possible by means of the molded parts. Preferably, the individual layers are placed inside each other.

Another layer of filling compound 22 is mainly used for the purpose of assembly. As materials, for example, high-temperature resistant plastic repair ceramic materials for ceramic fiber applications can be used.

The largest insulation effect in Dämmverbund is achieved by means of microporous insulating materials 26. Here, materials with low thermal conductivity, such as inorganic silicatic substances based on highly dispersed silicic acid are preferably used. A useful material for the invention may for example consist of 80% S1O2, 15% SiC and impurities.

Preferably, the insulation materials are in prefabricated shells, half shells, pipe shells, casings, Dämmplattten or other moldings. Depending on the application, the molded parts can be single-layered or multi-layered, e.g. Be laid 2- or 3-ply, but preferably at least 2-ply. This allows a joint offset or staggered assembly and / or the use of sealing strips, which significantly reduces the risk of flowing through the insulation. The individual layers of the microporous insulation are preferably glued together. The connection to the metallic outer tube 6 can also be carried out by means of gluing.

The pressure-bearing metallic tube 2 (which may be made of steel or stainless steel, for example) implements the pressure-tight closure to the outside. Due to the low temperature, low-temperature-resistant metallic materials can be used. To avoid condensation on the inside of the outer tube, additional insulation can be provided from the outside. This is not shown. Reference numeral 28 denotes a flange which is disposed on the outer tubular body 2.

In Fig. 2, an embodiment of the invention, the segmental design of the inner tube is shown, wherein the plug connection is realized via a cone segment. Here, at least a part of the segment is conical. It can be seen, however, that here the entire pipe segment is frusto-conical. It would, as mentioned above, also conceivable in one end region, a step, which is then introduced into another segment. It can further be seen that in this embodiment the inner tubular body widens in its cross section by only 4 mm, which corresponds approximately to the thickness of the inner tubular body 4. As a result of this relatively slight widening over the entire segment length (the segment length is 896 mm, the cross-section of the inner tubular body is considered to be constant and hence favorable in terms of flow.) Preferably two successive segments in the longitudinal direction of the segments overlap in a range between 20mm and 200mm, preferably a range of 20mm and 150mm, preferably between 30mm and 100mm and more preferably between 40mm and 60mm, respectively in relation to the segment length of 896mm, ie for shorter or longer segments the overlap is correspondingly smaller or larger.

FIG. 3 shows a further embodiment of the invention, from which also the butting assembly of the sealing material 14 and the microporous sealing material 26 can be seen. Reference symbol L denotes a longitudinal direction of the pipeline device which also corresponds to the flow direction of a medium flowing through the pipeline device. The reference symbol R denotes a radial direction, in which the individual thicknesses indicated above are defined.

For the purpose of the assembly already described above, the first layer of the insulating material and any sealing strips with the outer tube ie the outer tubular body 2 is glued. Each additional layer of insulating material and any other sealing strips is then glued to the already glued layer. The unit of outer tube 2 and the glued Th insulating material 26 is lowered over the fixed unit with fixing aids, preferably with winding film, fixed inner tubular body 4, fiber mats 12 and sealing material 14. Subsequently, the centering 8 is fixed to the flange of the outer tube 6 by means of clamping means, such as clamps or screw 10. Furthermore, a centering aid 9 is fixed to the opposite flange with the outer tube also by means of clamping means 10.

The centering serve the purpose of transport and / or installation of the pipe in the proposed pipeline network. In the final step, the gap between the microporous sealing material 26 and the sealing material 14 is filled with prior art filling material 22 (e.g., ceramic restoration compounds) in at least one operation. Preferably, the gap is split in two passes, e.g. advantageously filled in the form of a strip filling. In two or more operations thus drying of the filler is possible.

According to the present invention, as shown in Fig. 4, T-shaped piping can be isolated. Accordingly, the inner tube is subdivided into a T-shaped section 4a and at least three straight tube sections 4b. Two pipe sections 4b of the inner tube are inserted into each other with the two axial ends of the T-shaped inner tube 4a and encased with the fiber mats 12.

The pipe section thus mounted is placed and centered perpendicular to the centering aid 8 located in the first assembly step. Thereafter, the sealing material 14 is preferably placed in the form of half-shells around the longitudinal tube sides. In a further assembly step, the T-shaped metallic outer tube 2 a with the microporous sealing material 26 is laid with a staggered offset and any necessary sealing strips are laid. The metallic outer tube 2a with the assembled microporous sealing material 26 is placed over the inner tube, fixed with the centering 8 by means of the clamping means 10 and linked to another centering 9 and also fixed with clamping means 10.

In the next step, the filling of the gap between the sealing material 14 and the microporous sealing material 22 with filling compound preferably takes place in at least one operation. Preferably, the gap is filled in two operations, for example, advantageously in the form of a strip filling. In two or more operations is thus drying of the Filler possible. Subsequently, the T-piece is folded over, so that the inner tube 1 b can be inserted into the T-piece inner tube part 6a. Now, the sheathing of quasi free-standing inner tube 6b with the fiber mats 2, the insertion of the sealing material 14 and possibly mounting the sealing strips (not shown in Fig. 4), center and fix the inner tube with the centering aid 1 1 and filling the remaining gap with the filling compound 22nd

The Applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided that they are novel individually or in combination with the prior art. It is further pointed out that features have also been described in the individual figures, which in themselves can be advantageous. The person skilled in the art immediately recognizes that a particular feature described in one figure can also be advantageous without taking over further features from this figure. Furthermore, the person skilled in the art recognizes that advantages can also result from a combination of several features shown in individual or in different figures.

LIST OF REFERENCE NUMBERS

1 pipeline device

2 outer tubular body

4 inner tubular body

4a inner tube, T-piece

4b inner tube, straight tube piece

8 centering aid

9 Centering aid

10 clamping means

1 1 centering aid

12 fiber mats

14 sealing material

16 sealing strips

22 filling material

26 Microporous sealing material flange

Longitudinal radial direction

Claims

claims

A conduit means (1) for directing flowable media having an outer first tubular body (2) which is impermeable to the flowable medium and which is suitable and intended to withstand a pressure applied by the fluid medium, within a first tubular body (2). arranged second tubular body (4), which serves to guide the flowable medium and which at least partially consists of a porous material, characterized in that

between the first rohrformigen body (2) and the second rohrformigen body (4) at least partially an insulating medium (12, 14) is arranged and the second tubular body (4) is made at least partially of a fiber-reinforced and ceramic-containing material.

Pipe device (1) according to claim 1,

characterized in that

the first tubular body (2) is made of a metallic material.

Pipe device (1) according to at least one of the preceding claims, characterized in that

a porosity of the material of the second tubular body (4) is between 10% and 40%, preferably between 25% and 35% and particularly preferably between 28% and 32%.

a thickness of the second tubular body (4) is between 1 mm and 15 mm, preferably between 1 mm and 10 mm and particularly preferably between 1 mm and 5 mm.

Pipe device (1) according to at least one of the preceding claims, characterized in that the fiber content of the ceramic-like material in a matrix is between 25% and 50%, particularly preferably between 30% and 45% and particularly preferably between 35% and 40%.

a material of the fibers of the fiber reinforced material is selected from a group of materials including aluminum silicate fibers, mullite fibers, Al 2 O 3 fibers, SIO 2 fibers, Al 2 O 3 - S1O 2 fibers, SiC fibers, SiBNC fibers, SiCN fibers.

a material of the matrix is selected from a group of materials which aluminum silicates, mullite, Al ₂ 0 ₃ , YSZ, Si0 ₂ , SiC, Si ₃ N ₄ , Zr0 ₂ or the system Al ₂ 0 ₃ -Si0 ₂ - Zr0 ₂ contains.

the second tubular body (4) is segmented.

on an outer periphery of the second tubular body (4) planar body are arranged in particular of aluminum silicate and / or aluminum oxide.

A device for generating power and heat with at least one turbine and at least one pipeline device (1) according to at least one of the preceding claims.

Method for producing a pipeline device with the steps:

- providing an inner tubular body (4);

- attaching fiber mats to the inner tubular body (4);

- Arrangement of a sealing material around an outer periphery of this inner tubular body; - Mounting the provided with the sealing material inner rohrformigen body in an outer rohrformigen body (2).