BE1029023B1 - Two-stage insulation of system parts carrying warm gases - Google Patents

Abstract

The present invention relates to a device for transporting or converting warm gases, the device having a housing 20, a first insulation layer 60 being arranged on or in the housing, the first insulation layer 60 having areas of increased thermal conductivity 30, 32, characterized characterized in that a second insulating layer 50 in the form of a coat of paint is arranged above the first insulating layer 60 in the areas of increased thermal conductivity 30, 32.

Description

Two-stage insulation of plant parts carrying warm gases The invention relates to the selective insulation of plants, in particular to prevent internal corrosion.

Plant components through which warm gas streams flow are usually insulated. A typical case is that, for example, mineral wool is installed on the outside. To hold these, anchors are used to attach the mineral wool to the housing of the plant components. However, these anchors have a higher thermal conductivity. This means that the temperature on the inside at the location of the armature is lower, which in turn can lead to condensation on the inside of the housing and, as a result, to corrosion. An alkali-resistant ceramic product and protective layer with feldspar as the base material is known from DE 10 2007 042 881 A1. From CN 107032735 B a thermal insulation coating for boilers is known. CN 104559393 A discloses a heat-insulating and anti-corrosion coating material for pipelines. The object of the invention is to ensure insulation of these areas with increased thermal conductivity, but without insulating too much, in order to avoid a loss of rigidity or strength due to excessive local temperature increases. This object is achieved by a device having the features specified in claim 1 and by the method having the features specified in claim 7 . Advantageous developments result from the dependent claims, the following description and the drawings. The device according to the invention is used for transporting or converting warm media. Media are, for example, process gases or heat exchange fluids.

For example, it can be a matter of simple pipelines.

However, it can also be a calciner or a preheater, for example.

The device can also be part of an exhaust gas treatment system, for example.

In the context of the invention, warm gases can cover a very wide temperature spectrum.

For example, the warm gases can occur in a temperature range from 60° C. to 1200° C., for example in a cement works.

The invention is particularly relevant in a temperature window of 60° C. to 400° C., since here cooling can lead to condensation of water at the corresponding points, which can then in turn lead to increased corrosion.

Water can no longer condense above 374 °C.

The device has a housing.

A housing is to be understood broadly within the meaning of the invention.

For example, the housing can also simply be a tube, for example.

A first insulation layer is arranged on or in the housing.

If the housing is double-walled, for example, the first insulation layer can be arranged between the two walls of the housing.

Likewise, the first insulating layer can be arranged in or on the housing, for example also wound around the first housing. Furthermore, the housing and the first insulating layer can form a physical unit.

The first insulation layer has areas of increased thermal conductivity.

At this point, several problems arise.

On the one hand, these places are particularly warm on the outside, so that there is a risk of injury.

Furthermore, the gas inside also loses more heat, which is lost to the overall process and simply given off to the environment.

And thirdly, the warm gas inside the device can be selectively cooled in such a way that condensation occurs, which in turn entails an increased risk of corrosion.

It is therefore provided according to the invention that a second insulation layer in the form of a coat of paint is arranged above or on the other side of the first insulation layer in the areas of increased thermal conductivity.

A coat of paint has the advantage that it can also be applied very selectively, also selectively in different thicknesses and thus different degrees of insulation.

This provides optimal adaptability in order to avoid temperature peaks both on the outside and in particular on the inside of the device and thus to effectively prevent condensation but also not through too high a condensation

Temperature to locally affect the rigidity or strength of the housing at too strong local isolation.

In a further embodiment of the invention, the first insulation layer has mineral wool.

The mineral wool is fixed with anchors and the anchors form the areas of increased thermal conductivity.

This means that the paint is placed above the anchors.

In a further embodiment of the invention, the areas of increased thermal conductivity are formed by connecting elements, for example screws, bolts or rivets.

In a further embodiment of the invention, the areas of increased thermal conductivity are formed by expansion compensators.

Expansion compensators are, for example, places where the circumference is increased in a wavy manner.

Alternatively, for example, two tubes can be arranged so that they can move inside one another.

In this way, a change in length, in particular due to a change in temperature, can be compensated for.

On the one hand, however, this may influence the insulation of the first insulation layer in this area.

On the other hand, movements occur here, which must also be taken into account.

In a further embodiment of the invention, the paint has at least 70% oxidic particles with a size of 2 nm to 100 nm.

The proportion of oxidic particles is preferably higher, preferably at least 75%, particularly preferably at least 80%. The oxidic particles are preferably oxides of aluminum, silicon, titanium, zinc, indium, tin or a combination of these elements.

For example and preferred are the oxidic particles of titanium dioxide.

For example and preferably, the oxidic particles are produced by means of a so-called bottom-up synthesis in solution.

The advantage over production by grinding (top-down synthesis) is that the particle size distribution is much narrower, the particles have a more uniform spherical shape and good internal crystallinity.

In a further embodiment of the invention, the paint has a silicon-containing component which binds the oxidic particles together.

For example, the

Paint a silane or siloxane compound. When the paint is applied, this component causes silicate bridges to be created between the oxidic particles, thus creating a strong and durable bond that is extremely thermally stable.

In a further aspect, the invention relates to a method for preventing corrosion in a device through which warm, moist gas flows. The device has a housing with a first insulation layer arranged on or in the housing. The method comprises the following steps: a) identifying at least one area with increased thermal conductivity, b) applying a paint to form a second insulation layer. The application is particularly preferably carried out as a function of the strength of the thermal conductivity. For example, an area that has very good thermal conductivity would be coated with a thicker coat of paint, such as multiple coats. This can be the case, for example, if, for example, two different types of anchors are used within the first insulation layer, which, for example, have different strengths.

This shows the great advantage of the method. By using a paint to form a second insulation layer, it is possible to react very flexibly to variations and thus achieve a very uniform insulation, whereby both temperature sinks and temperature peaks in the housing and thus in the gas coming into contact with the housing can be avoided.

In a further embodiment of the invention, a coating with at least 70% oxidic particles with a size of 2 nm to 100 nm is used for application in step b).

In a further embodiment of the invention, the identification in step a) takes place with the aid of a thermal imaging camera. Alternatively, the identification in step a) can theoretically be based on the positions of anchors in the first insulation layer.

In a further embodiment of the invention, the identification in step a) takes place by discoloring the paint.

This is particularly preferred in order to find areas of increased thermal conductivity that develop or change over time and then further isolate them. 5 The coating according to the invention is explained in more detail below with reference to an exemplary embodiment illustrated in the drawings.

1 first cross section FIG. 2 second cross section FIG. 3 third cross section FIG. 4 fourth cross section FIG. 5 fifth cross section The illustrations are highly schematic and not true to scale.

The figures are for illustrative purposes only.

A cross section through one side of a device according to the invention is shown in each case.

In Fig. 1 in a first exemplary embodiment of a device according to the invention.

At the inner wall 10, the warm gases come into contact with the housing 20 of the device.

In an area of increased thermal conductivity 30, an area with a reduced temperature could therefore occur on the inner wall, so that the risk of condensation is increased here, which in turn increases the risk of corrosion in the vicinity of the area of increased thermal conductivity 30.

The housing 20 is surrounded by a first insulation layer 60 at all other points.

A cover layer 40 adjoins the first insulation layer 60 .

In order to reduce the aforementioned risk of corrosion, a second insulating layer 50 in the form of a coat of paint is applied locally to the cover layer 40 in the area of increased thermal conductivity 30 .

For example, the Bronya-CE Classic nf paint from SF Concepta GmbH, which contains 80% titanium dioxide, can be used as a coat of paint.

The thickness of the second insulating layer 50 can be 0.5 mm, for example.

If the first insulation layer 60 is mineral wool, it can typically have a thickness of a few cm.

2 shows a slightly modified embodiment compared to FIG. 1. In this second example, the second insulation layer 50 is applied over the entire surface with a thickness of 0.5 mm, for example, and in the area of increased thermal conductivity 30 with an increased layer thickness of 1 mm, for example . This can be done, for example, by a second coat over a first dried coat. In addition to the area of increased thermal conductivity 30, a further area of increased thermal conductivity 32 is shown in FIG. By way of example, the further area of increased thermal conductivity 32 is twice as thick as the area of increased thermal conductivity 30, which results in better thermal conductivity. The advantage of using a paint to produce the second insulation layer 50 can be seen. Here, for example, in the wider area of increased thermal conductivity 32, a layer thickness of 1.5 mm can produce locally better thermal insulation compared to a 1 mm thick second insulation layer 50 in the area of increased thermal conductivity 30. FIG. 4 shows the case analogous to FIG. 1, with the first insulation layer 60 being arranged inside the housing 20. For example, the first insulating layer 60 can be a lining. FIG. 5 shows the case analogous to FIG. 2 , with the first insulation layer 60 being arranged inside the housing 20 as in FIG. 4 . For example, the first insulating layer 60 can be a lining.

Reference numeral 10 inner wall 20 housing area of increased thermal conductivity 30 32 further area of increased thermal conductivity 40 cover layer 50 second insulating layer 60 first insulating layer

Claims (11)

/ BE2021/5023 patent claims A device for transporting or converting warm media, the device having a housing (20), a first insulating layer (60) being arranged on or in the housing (20), the first insulating layer (60) having areas of increased thermal conductivity (30, 32), characterized in that a second insulation layer (50) in the form of a coat of paint is arranged above or on the other side of the first insulation layer (60) in the areas of increased thermal conductivity (30, 32). 2. Device according to claim 1, characterized in that the first insulation layer (60) comprises mineral wool, the mineral wool being fastened with anchors, the anchors forming the areas of increased thermal conductivity (30, 32). 3. Device according to claim 1, characterized in that the areas of increased thermal conductivity (30, 32) are formed by connecting elements, for example screws, bolts or rivets. 4. Device according to claim 1, characterized in that the areas of increased thermal conductivity (30, 32) are formed by expansion compensators. 5. Device according to one of the preceding claims, characterized in that the paint has at least 70% oxidic particles with a size of 2 nm to 100 nm. 6. The device as claimed in claim 5, characterized in that the coating has a silicon-containing component which links the oxidic particles. 7. A method for preventing corrosion in a device through which warm, moist gas flows, the device having a housing (20) with a first insulating layer (60) arranged on or in the housing (20), the method comprising the following steps: a) identifying at least one area with increased thermal conductivity (30, 32), b) applying a paint to form a second insulating layer (50). 8. The method according to claim 7, characterized in that a coating with at least 70% oxidic particles with a size of 2 nm to 100 nm is used for application in step b). 9. The method according to any one of claims 7 to 8, characterized in that the identification in step a) takes place with the aid of a thermal imaging camera. 10. The method according to any one of claims 7 to 9, characterized in that the identification in step a) is theoretically based on the positions of anchors in the first insulation layer (60). 11. The method according to any one of claims 7 to 10, characterized in that the identification in step a) takes place by discoloring the paint.