Heat exchanger of an adsorption dryer

Abstract

The invention relates to a heat exchanger for arranging in a pressure container, which has a granular adsorption material, of an adsorption dryer which is designed to dry a pressurized gas, in particular compressed air, and for transferring heat of a heat transfer medium, in particular oil, to the granular adsorption material, comprising a heating section for transferring heat from the heat transfer medium to the adsorption material, said heating section comprising multiple media lines (1202, 1402), each of which has at least one media channel, for conducting the heat transfer medium in the media line, wherein the heating section substantially has a cylindrical shape with a longitudinal axis, the media lines are arranged on multiple line planes in the direction of the longitudinal axis, the media lines are designed and are interconnected such that the heat transfer medium can flow through the media lines collectively in parallel and / or in series, adjacent line planes and / or media lines of adjacent line planes are mutually spaced in the direction of the longitudinal axis, and the media lines are designed as extruded profiled sections.

Description

[0001] Heat exchanger of an adsorption dryer

[0002] The present invention relates to a heat exchanger for arrangement in a pressure vessel of an adsorption dryer. The present invention also relates to a corresponding adsorption dryer. The present invention also relates to a method for operating an adsorption dryer with a heat exchanger.

[0003] Rectangular heat exchangers are used for many applications, such as the compressed air industry. Various designs of heat exchanger elements are available. A widely used material for heat exchangers is aluminum, or aluminum alloy. This material allows for the production of extruded profiles with one or more internal channels and a relatively large surface area under economically attractive conditions. The wall thicknesses can sometimes be small, typically less than one millimeter. This results in short heat conduction distances within the material. Such profiles are also referred to as "microchannel profiles."

[0004] One known use for such profiles could be, for example, to construct a heat exchanger with several such microchannel profiles arranged parallel to one another, which are connected to a manifold at one end and to a manifold at the other end. One manifold is connected to the fluid inlet, the other to the fluid outlet.

[0005] The individual microchannel profiles are connected in the spaces between them by fins / fins for heat conduction. A fluid can flow through the inner channels of the profiles, and ambient air, for example, can flow around the profiles and fins. Such heat exchangers are used, for example, in the compressed air industry, as condensers in refrigeration dryers.

[0006] In addition to heat exchangers made from microchannel profiles, there are other well-known heat exchanger designs, such as those using fins. Here, fins / sheets are positioned next to each other at intervals of, for example, a few millimeters, and are interspersed with one or more tubes. While one fluid, e.g., water, flows through the tubes, the other fluid, e.g., air, flows around the surface of the tubes and fins. The large surface area of ​​the fins enables good heat exchange. Various materials can be used for such heat exchangers.

[0007] There are also heat exchanger designs that are suitable for a round installation space, or can be conveniently manufactured as a single round component. Such well-known designs include coiled-tube heat exchangers, which allow a long pipe section to be placed in a compact installation space.

[0008] Another well-known round heat exchanger design is a spiral heat exchanger. This features two concentric spiral flow channels through which two media can flow separately, for example, using a counterflow or crossflow principle.

[0009] The finned heat exchangers described above are also available in round versions, for example when used in conjunction with fans.

[0010] However, special requirements may arise for use in a modern regeneration system, especially with an adsorption dryer. Such an adsorption dryer can dry a compressed gas in a pressure vessel filled with desiccant. This desiccant needs to be regenerated, and heat can be supplied via a heat exchanger for this purpose. The heat should therefore be supplied via the heat exchanger within the desiccant. In addition, heated compressor oil from a compressor of the adsorption dryer can be used for heat supply, as shown in US Pat. No. 4,898,599.

[0011] For the described regeneration mode, with heat input within the drying agent from the heated compressor oil, a heat exchanger with a special design is required to ensure sufficient heat input into the regeneration air and the drying material. This requires the use of a suitable material and geometry for the heat exchanger. In addition to a large surface area, favorable airflow through the regeneration air is also important.

[0012] The present invention is therefore based on the object of addressing at least one of the aforementioned problems. In particular, a solution is to be proposed in which a heat exchanger can be used for a described novel mode of operation of the regeneration operation with heat input within the desiccant, in particular through heated compressor oil, in order to enable the highest possible heat input into the regeneration air and the desiccant. At least an alternative solution to previously known solutions is to be proposed.

[0013] According to the invention, a heat exchanger according to claim 1 is proposed. The invention thus relates to a heat exchanger for arrangement in a pressure vessel. This comprises a granular adsorption material, which can also be referred to as a desiccant, and is intended for drying a compressed gas, in particular compressed air. The pressure vessel is part of an adsorption dryer. The heat exchanger is thus arranged in such a pressure vessel for transferring heat from a carrier medium, in particular oil, to the granular adsorption material. This transfer of heat to the granular adsorption material is provided in a regeneration mode.

[0014] The adsorption dryer operates in such a way that drying and regeneration operations can alternate. The heat exchanger is then particularly active during regeneration operation and has a heating section for transferring heat from the heat transfer medium to the adsorption material. Essentially, the entire heating section can be referred to as a heat exchanger; in practice, however, in addition to the actual heating section, in which heat transfer takes place, there are also sections for connecting the heat exchanger and thus the heating section to supply or discharge lines. Mounting sections for attaching or at least securing the heat exchanger or heating section in the pressure vessel may also be added.

[0015] The heating section and thus naturally also the heat exchanger comprises a plurality of medium lines, each having at least one medium channel, for guiding the heat transfer medium in the medium line, wherein the heating section has a substantially cylindrical shape with a longitudinal axis. The heating section therefore comprises not just one, but several medium lines in which the heat transfer medium is guided. In particular, oil, in particular oil from a pressure compressor, i.e. compressor oil, can be guided therein. The cylindrical shape is to be understood in particular as a circular cylindrical shape. Of course, minor deviations from an ideal circular shape are conceivable. In particular, it is proposed that the cylindrical shape of the heating section be oriented towards the shape of the pressure vessel in order to be able to be pushed into or pulled out of the pressure vessel in the direction of the longitudinal axis.

[0016] The medium lines are arranged in several levels along the longitudinal axis. With a vertical arrangement of the longitudinal axis, several levels of lines are arranged one above the other. This allows heating to take place in these multiple levels, thus achieving the most uniform heating possible within the pressure vessel.

[0017] The medium lines are designed and connected to one another so that the heat transfer medium can flow through them together in parallel and / or in series. For example, the medium lines can be arranged between two common header lines and thus connected in parallel, with the heat transfer medium flowing in through one header line, then flowing through all the medium lines and flowing out again at the other header line. However, the medium lines can also be designed and connected to one another so that the heat transfer medium first flows through one medium line and then from its outlet through the next medium line, and so on. A combination can also be provided, for example with flow through two medium lines in parallel and then from their common outlet through the next two medium lines.

[0018] It is further proposed that adjacent line levels and / or medium lines of adjacent line levels be spaced apart from one another in the direction of the longitudinal axis. In particular, they can be spaced apart such that they are essentially completely surrounded by the adsorption material. The adsorption material can particularly be designed as a bulk material and can then be poured into the pressure vessel, in which the heat exchanger or its heating section is already arranged. The adsorption material is then also poured into these spaces between longitudinally adjacent medium lines. Heat can then be evenly transferred from the medium lines to the adsorption material surrounding them.

[0019] It is also proposed that the medium lines be designed as extruded profiles. By using extruded profiles, essentially any desired shape of the medium lines can be created and thus also predetermined. The medium lines can thus each form at least one medium channel for guiding the heat transfer medium essentially independently of the external shape of the medium line. The medium channel can therefore be predetermined in such a way that it is well suited to guiding the heat transfer medium, in particular for guiding a corresponding oil. Independently of this, the external shape of the medium line can be predetermined in such a way that good and even transfer of heat to the adsorption material and also to a regeneration gas used to regenerate the adsorption material, in particular regeneration air, can be achieved.This allows for a suitable overall cross-section to be specified, which also achieves the required stability of the medium lines. The resulting shapes can be easily realized using an extrusion process, using a suitable material such as aluminum or an aluminum alloy, which achieves good stability with good thermal conductivity.

[0020] By using extruded profiles, for example, with a round cross-section of the medium channels, or of one of the medium channels, a partially straight outer profile can be created in order to be able to easily attach heat conducting plates or fins to it.

[0021] Likewise, the use of an extruded profile can create a suitable cross-section that can withstand a pressure difference, particularly a pressure difference in the pressure vessel. During the regeneration phase, an overpressure in the heat exchanger can occur compared to the pressure in the pressure vessel, e.g., 11 bar as absolute pressure in the heat exchanger compared to an absolute pressure of, for example, 1 bar or even 0.3 bar in the pressure vessel.

[0022] Thus, a heat exchanger is proposed that is highly suitable for use in a pressure vessel of an adsorption drying device. During regeneration operation, in which the adsorption material is dried, i.e., regenerated, the heat exchanger can effectively transfer heat to the adsorption material and to the regeneration gas, in particular regeneration air, flowing through it for regeneration. Already dried compressed gas, in particular already dried compressed air, can be used as the regeneration gas, either in whole or in part. The corresponding heat can be supplied by an oil, in particular compressor oil. The invention also proposes a heat exchanger according to claim 2. For this heat exchanger, it is provided that the medium lines are provided with heat conducting plates.This allows the heat from the medium lines to be better transferred to the adsorption material and the regeneration gas, in particular regeneration air, intended for drying the adsorption material.

[0023] For this purpose, it is further proposed that the heat conducting plates be spaced apart such that a bed of granular adsorption material with a maximum grain size of up to 12 mm, preferably up to 8 mm, and in particular up to 5 mm is possible between two adjacent heat conducting plates of the same medium line. Thus, at least one adsorption material, i.e. drying agent, can be selected that has a maximum grain size of 5 mm. Put simply, the largest grain of the adsorption material can have a diameter of 5 mm. The grain size can be defined by the equivalent diameter, namely the volume-equivalent sphere diameter. This grain size then refers to the diameter that a sphere with the same volume of the non-spherical grain would have. Here, however, a different, yet very similar definition is used, in which the largest diagonal or the largest diameter is used as the grain size.The desiccant can be almost spherical, which is why the different definitions do not differ greatly.

[0024] Heat exchangers with fins are known to achieve very good heat transfer to the surrounding air or to another liquid or gaseous medium. However, it was recognized that a large amount of heat also needs to be transferred directly to the adsorption material. Therefore, the familiar, delicate fins are unsuitable. Furthermore, such delicate fins also run the risk of being damaged by the adsorption material, which is provided as bulk material.

[0025] Therefore, it is proposed to arrange heat-conducting plates at such a distance from each other that the granulate, i.e., the adsorption material, can also be poured between them. In particular, it is proposed that the heat-conducting plates be aligned vertically, relative to an arrangement with a vertical longitudinal axis. The heat-conducting plates are thus aligned, in particular, parallel to the longitudinal axis.

[0026] Preferably, the heat conducting plates have a thickness of at least 0.08 mm, in particular at least 0.1 mm, in order not only to conduct heat well, but also to be sufficiently stable so as not to be damaged by a filling of the adsorption material.

[0027] Additionally or alternatively, it is proposed that adjacent heat-conducting plates of the same medium line be spaced apart by at least 6 mm, preferably at least 9 mm, and in particular at least 15 mm. Such a spacing ensures that a granular adsorption material with the specified grain sizes can also be poured between the heat-conducting plates.

[0028] The heat exchanger, in particular the heating section, is thus well adapted for use in a pressure vessel for the regeneration of an adsorption material of an adsorption dryer.

[0029] According to one aspect, it is proposed that in each of the line levels, exactly one at least partially circumferential line section of a medium line is provided, or at least two line sections of a medium line are arranged parallel to one another, with an intermediate distance between the line sections that is at least 6 mm, preferably at least 9 mm, in particular at least 15 mm and / or that allows a filling of granular adsorption material with a maximum grain size of up to 12 mm, preferably up to 8 mm, in particular up to 5 mm in the intermediate distance. Thus, either a single medium line is provided per level, or several, between which the adsorption material can be poured.

[0030] It is further proposed that the heating section has a circular shape and / or a circular outer contour and / or at least in sections a spiral shape in one of the line levels.

[0031] It was particularly recognized here that the pressure vessel into which the heating section is to be inserted should have a circular cylindrical shape in order to be able to withstand the corresponding pressure. The shape of the heating section in the line levels is adapted to this. A circular shape and / or outer contour is therefore proposed. The use of a spiral shape is also very similar to such a circular shape. Although it deviates somewhat and is therefore not ideal, it has the advantage that the medium flow through the medium lines can be easily guided in such a spiral shape, while at the same time several sections of a line level can run essentially parallel to one another. In particular, such a spiral shape can therefore fill the pressure vessel well and at the same time ensure good medium flow, with simultaneous good heat transfer from the heating section to the granular adsorption material.

[0032] According to one aspect, it is proposed that the heating section for arrangement in a pressure vessel with a circular-cylindrical or annular gap-shaped interior has, in each case in one of the line levels, a curved outer contour adapted to the interior.

[0033] Here, too, a circular-cylindrical pressure vessel is proposed for good pressure absorption. However, it can also have a circular-cylindrical division within its interior, resulting in a circular-cylindrical annular gap. To achieve this, it is proposed that the heating section be adapted to this internal shape of the pressure vessel. The outer contour of the heating section, in particular, is adapted to this and preferably has a curved outer contour. This ensures a good fit and can simultaneously achieve good flow of the heat transfer medium.

[0034] If an annular gap-shaped interior is provided, the heating section is adapted to this and thus has a cylindrical shell shape similar to that of a circular cylinder, which can be inserted into such an annular gap. However, even in this case, the heating section is designed so that the granular adsorption material can be poured between the individual medium lines and / or heat conducting plates.

[0035] According to one aspect, it is proposed that the at least one medium channel has an average diameter and the medium line to the medium channel has a wall thickness and a ratio between the average diameter of the medium channel and the wall thickness is in the range from 2 to 50, in particular 5 to 25, and / or the wall thickness has a thickness of 0.15 mm to 2 mm, in particular 0.15 mm to 1.5 mm.

[0036] In particular, a circular medium channel can be assumed here, so that its diameter corresponds to the mean diameter. If the shape is not circular, it can be calculated as the average between the largest and smallest diameter. The wall thickness is therefore the thickness of the wall between the medium channel and the outer contour of the medium line. The smallest wall thickness can be used as a basis here. It was particularly recognized that the mean diameter should be significantly larger than the wall thickness and that such a profile also achieves sufficient stability and, at the same time, sufficiently good thermal conductivity from the medium channel to the outside. In particular, a mean diameter at least five times the wall thickness is recommended in order to achieve good flow properties for the heat transfer medium.This means that oil can also be used as a heat transfer medium and still flow well without causing an excessive pressure drop in the heat transfer medium in the medium channel.

[0037] With a wall thickness of at least 0.15 mm, up to 2 mm, in particular 0.15 mm to 1.5 mm, a high stability of the medium line can be achieved, while at the same time good heat transfer.

[0038] According to one aspect, it is proposed that the medium lines each have an elongated cross-section having a longitudinal dimension in the direction of the longitudinal axis of the heating section and a transverse dimension transverse thereto, wherein the longitudinal dimension is at least 1.5 times, in particular at least twice, the transverse dimension. The longitudinal dimension can also be referred to as the diameter of the medium line in the longitudinal direction, and the transverse dimension can be referred to as the diameter of the medium line in a direction transverse to the longitudinal axis.

[0039] The cross-section of the medium line is designed such that the medium line presents very little flow resistance to the compressed gas or regeneration gas in the longitudinal direction, while offering a larger surface area in the transverse direction, which is suitable for heat dissipation. The compressed gas or regeneration gas flows through the pressure vessel and thus also the heating section primarily in the longitudinal direction, i.e., along the longitudinal axis of the heating section, so that the medium line presents little flow resistance to this flow while simultaneously dissipating a large amount of heat.

[0040] Additionally or alternatively, the medium line has at least two medium channels running parallel to one another, wherein these at least two parallel medium channels are aligned and spaced apart in the direction of the longitudinal axis. If the longitudinal axis is arranged vertically, these medium channels are arranged one above the other. This also fits well with the elongated cross-section of the medium line, which is aligned in the longitudinal direction of the longitudinal axis, or rather, such an arrangement of several medium channels leads to such an elongated cross-section. This ensures that the heat transfer medium can flow easily through the medium line, wherein the division into several medium channels promotes laminar flow, while at the same time the medium line offers little flow resistance to the compressed gas flowing through the pressure vessel.

[0041] Despite the preferred design of multiple medium channels, an alternative design may also be advantageous to provide only one medium channel in the medium line. This allows the medium line to be designed in a simple manner and also allows for more adjacent line levels in the pressure vessel. With more adjacent line levels, these can sometimes be better surrounded by the granular adsorption material, thereby achieving good heat transfer from the medium line to the adsorption material.

[0042] According to one aspect, it is proposed that the medium lines be designed as extruded profiles, in particular made of aluminum and / or aluminum alloy. It has been particularly recognized that this allows the medium lines to be easily manufactured in the desired shape. In particular, they can be manufactured as described above, and the above-described ratios between the average diameter of the medium channel and the wall thickness can thus be realized. The desired wall thickness can also be realized in the manner specified above.

[0043] By using aluminum or an aluminum alloy, such an extrusion manufacturing process can be carried out well and at the same time, good thermal conductivity is achieved, so that heat can be easily transferred from the carrier medium to the environment, especially to the granular adsorption material, via the extruded profile.

[0044] According to one aspect, it is proposed that the heating section have a plurality of collecting lines, and these collecting lines comprise a supply channel for supplying the heat transfer medium and a discharge channel for discharging the heat transfer medium, wherein the supply channel and the discharge channel are each arranged parallel to the longitudinal axis and the medium lines are each arranged between the supply channel and the discharge channel, so that the heat transfer medium flows parallel through the medium lines from the supply channel to the discharge channel. The collecting lines, which are particularly preferably designed as collecting pipes, thus connect a plurality of medium lines. It is conceivable that only the supply channel and the discharge channel are present as collecting lines, but further collecting lines can also be provided, for example to create further subdivisions and / or series connections between the medium lines.

[0045] The supply duct and the discharge duct are thus arranged parallel to each other, with the medium lines arranged between them. Essentially, the supply duct and the discharge duct also connect the individual line levels. The supply duct and the discharge duct can also run adjacent to each other, with a distance that is less than the average diameter of each supply duct, or at least less than twice or three times the diameter of the supply or discharge duct.

[0046] Particularly with a circular arrangement of medium lines, they can form a semicircle or an almost complete circle from the supply channel to the discharge channel. The heat transfer medium can thus be easily supplied and discharged via the supply channel and the discharge channel. This allows for the simple and efficient design of the heating section.

[0047] The supply channel and the discharge channel can also be continued linearly in order to lead them out of the pressure vessel.

[0048] Such a heating section design, whether with or without linear routing of the supply and discharge channels, can also be easily inserted into or removed from the pressure vessel in the longitudinal direction. Such a shape can be advantageous, at least when inserting the heating section into a cylindrical pressure vessel.

[0049] According to one aspect, it is proposed that two medium lines adjacent to one another in the direction of the longitudinal axis are spaced from one another by a longitudinal distance which designates a free distance between them, wherein the longitudinal distance corresponds at least to a minimum thickness of the medium line. In other words, a minimum distance is provided between two medium lines in the longitudinal direction, and this distance is at least as large as the thickness of the medium line. If the medium lines are of different sizes, the thickness of the smaller medium line is used. In particular, it is proposed that the longitudinal distance corresponds to at least twice the minimum thickness of the medium line and in particular to a maximum of 5 times the minimum thickness of the medium line.

[0050] In particular, the minimum thickness of the medium line is taken into account here. If the medium line has an elongated cross-section and is aligned longitudinally, i.e., always relative to the longitudinal axis of the heating section, this thickness is used, which is then measured transversely to the longitudinal axis. Therefore, two medium lines adjacent longitudinally do not necessarily have to be spaced as far apart as their own longitudinal extension, but only at least as far apart as their transverse extension.

[0051] The idea behind this is that the longitudinal distance, namely the free distance, i.e. how much space there actually is between the two medium lines, should be filled with adsorption material so that the medium lines are surrounded as well as possible by the adsorption material.

[0052] It was already suggested above that the maximum grain size of the adsorption material be used as a basis for such distances. This is also proposed here: the two longitudinally spaced and adjacent medium lines should be spaced apart at a distance sufficient for the granular adsorption material to pass through this free space. The free space should therefore preferably correspond to at least 1.2 times the largest grain size of the adsorption material.

[0053] However, it was recognized here that the media lines also depend on the adsorption material used, particularly the maximum grain size, and thus the size of the media lines is also a good measure of how large the spacing between them should be. Therefore, a free spacing based on the minimum thickness of the media line is proposed here.

[0054] It can therefore be advantageous for the longitudinal spacing to be at least twice the thickness of the medium line. This allows particular consideration to be given to the fact that the medium line has a very small thickness transverse to its longitudinal axis, so that the longitudinal spacing between two adjacent medium lines should be at least twice as large. Preferably, the longitudinal spacing is a maximum of 5 times the minimum thickness of the medium line. It has been recognized here that too large a spacing can be disadvantageous because, although a good filling of the granular adsorption material is achieved, the heat input is significantly reduced due to the now widely spaced medium lines. The free spacing is therefore preferably in the range of twice to 5 times the thickness of the medium line.

[0055] According to one aspect, it is proposed that adjacent medium lines or adjacent medium line sections of the same line level are connected by heat conducting plates and / or that a plurality of medium lines or a plurality of medium line sections are guided parallel to one another transversely through a plurality of heat conducting plates by which they are connected, or, if the medium lines are designed as extruded profiles, the extruded profiles do not have any heat conducting plates protruding from the extruded profile.

[0056] In other words, adjacent medium lines of the same line level are arranged next to each other in a horizontal plane if the longitudinal axis is vertical. They can be connected by heat-conducting plates, which can be arranged between them. Such heat-conducting plates can, for example, be soldered or provided in some other way, in particular by means of a material bond.

[0057] This allows for effective heat dissipation because the heat-conducting plates additionally dissipate heat from the medium lines. Furthermore, high stability is achieved at the relevant line level.

[0058] If the medium lines are arranged in a spiral pattern, this would mean that the same medium line is connected to itself by the heat-conducting plates, because the spiral shape essentially means that it is parallel to itself. In this case, at least several medium line sections are adjacent to one another. With the aforementioned spiral pattern, the connection to the heat-conducting plates can also achieve particularly high stability.

[0059] It is also conceivable that the heat conducting sheets are provided in such a way that several medium lines are passed through these heat conducting sheets at a distance from one another. In the case of two medium lines arranged parallel to one another, each heat conducting sheet can have two openings, e.g. two bores, and one of the medium lines is passed through each opening. This naturally creates contact between the heat conducting sheets and the medium lines. In particular, a material connection can also be provided here between the heat conducting sheets and the medium line. One possible manufacturing option is to form a tubular section onto each sheet for each medium line, i.e. two tubular sections for two medium lines arranged parallel, and tubular sections of adjacent heat conducting sheets are inserted into one another to form a respective medium line.In principle, a spiral arrangement or design of the medium line can also be considered here, but a corresponding manufacturing process would be comparatively complex.

[0060] If extruded profiles are used, it is particularly suggested that these are designed in such a way that the extruded profile already has a good outer contour for dissipating heat, so that heat conducting plates can be dispensed with.

[0061] According to the invention, an adsorption dryer is also proposed. The adsorption dryer is intended for drying a compressed gas, in particular compressed air. It is equipped with at least one pressure vessel containing an adsorption material for adsorbing moisture from the compressed gas, which is filled into the pressure vessel, a drying inlet for admitting a compressed gas for drying, a drying outlet for discharging the compressed gas after drying, and a drying section through which the compressed gas flows during drying operation from the drying inlet to the drying outlet. At least one heat exchanger according to at least one of the aspects explained above has its heating section arranged in the pressure vessel, and the heating section is surrounded by the adsorption material, the adsorption material being in the form of granular bulk material.The adsorption material is therefore designed to adsorb moisture from the compressed gas, with the adsorption material being filled into the pressure vessel. Moisture adsorption occurs particularly in a process in which compressed gas is passed through the compressed gas vessel for drying and thus along the adsorption material. Accordingly, the drying inlet is designed to admit the compressed gas for drying, and the drying outlet is designed to discharge the compressed gas after drying. In between is the drying section, in which the compressed gas is dried, while during drying operation it flows through the drying section from the drying inlet to the drying outlet. For structural reasons and / or for functional purposes, the pressure vessel may not be completely filled with adsorption material.In this case, it has a transition zone in the area of ​​the drying inlet and / or the drying outlet, extending to the adsorption material, in which no adsorption material is arranged. Each transition zone can occupy approximately 3%-10% of the length from the drying inlet to the drying outlet. The drying section is a section in the adsorption material, i.e., a section from the drying inlet to the drying outlet, minus the at least one transition zone.

[0062] The heat exchanger is thus intended for heating the adsorption material. For this purpose, the heat exchanger, at least with its heating section, is arranged accordingly in the pressure vessel. The heating section, in particular, has medium lines spaced such that there is sufficient space between adjacent medium lines for the granular adsorption material to be poured between such medium lines.

[0063] Thus, the heat exchanger according to the invention can be used in such an adsorption dryer. It is operated in particular in a regeneration mode or a regeneration phase in which the adsorption material, which has absorbed moisture from the compressed gas, is dried again. For this purpose, a compressed gas, such as compressed air, which has been dried, can also be admitted into the pressure vessel. This can be done, for example, in the opposite direction to the drying of the compressed air, i.e., from the drying outlet back through the drying section to the drying inlet. All the advantages and features mentioned for the heat exchanger can be applied when used in the adsorption dryer. Properties of the adsorption material, particularly the grain size, which were explained above in connection with aspects of the heat exchanger, can also be applied here.In particular, the adsorption material can have a maximum grain size of up to 12 mm, preferably up to 8 mm, in particular up to 5 mm.

[0064] According to one aspect, it is proposed that the drying section has a first region facing the drying inlet and a second region facing the drying outlet, and that the heating section is arranged in the first region in each case and, in particular, that the heating section is not provided in the second region. The first and second regions are thus provided along the drying section, and it is preferably provided that the first region extends over at least 20% of the drying section, preferably over at least 30% of the drying section, in particular over at least 40% of the drying section, preferably a maximum of 70%, in particular a maximum of 60% of the drying section. The heating section should be arranged in this region. In particular, it is provided that no heating takes place outside the heating region, or at most reduced heating with less than 30% energy input per volume, compared to the heating region.

[0065] This is based on the idea that the heating section is only needed during the regeneration phase. During the regeneration phase, it is assumed that a regeneration gas, in particular regeneration air, flows from the drying outlet to the drying inlet and thus initially flows through an area, namely the second area, without a heating section, and only later through an area with a heating section and thus with heating. Here, it was recognized that the regeneration gas, i.e. the gas that flows through the pressure vessel to regenerate and thus dry the adsorption material, in particular regeneration air, is initially very dry upon flowing in and can therefore easily absorb moisture from the adsorption material. Furthermore, with this arrangement, it is to be expected that the adsorption material in the first area will have absorbed more moisture than in the second area. In the second area, less drying, and therefore less regeneration, is required.At the same time, the regeneration air itself is still very dry and can therefore absorb moisture better.

[0066] According to one aspect, it is thus proposed that a switching device be provided for switching between the drying mode and the regeneration mode. In regeneration mode, a regeneration gas flows through the pressure vessel and the drying section from the drying outlet to the drying inlet to remove moisture from the adsorption material, and the first region is heated, while the second region is not heated or is heated to a lesser extent. The regeneration gas can, in particular, be regeneration air, i.e., dry air. The regeneration gas then flows in the opposite direction compared to the drying mode. It therefore first reaches the adsorption material that the compressed gas to be dried last reached in the drying mode.

[0067] According to one aspect, it is proposed that the pressure vessel each have an annular gap space and a cylindrical interior space surrounded by the annular gap space, wherein the annular gap space and the cylindrical interior space are connected to one another in such a way that the compressed gas for drying can flow from the drying inlet via the annular gap space further via the cylindrical interior space to the drying outlet, and the heating section of the heat exchanger is arranged in the annular gap space, or the compressed gas for drying can flow from the drying inlet via the cylindrical interior space via the annular gap space to the drying outlet, and the heating section of the heat exchanger is arranged in the cylindrical interior space.

[0068] This allows for a solution in which both the compressed gas to be dried and the regeneration gas can flow into and out of the pressure vessel from the same side, for example, flowing in from below and out downwards if the pressure vessel is positioned vertically. Especially for dividing the pressure vessel so that the heating section is located in the annular gap, a circular heating section can be created in a simple and practical manner, particularly with circular line sections. This avoids a heating section precisely in the radial center, thus preventing very small bend diameters of the medium lines.This is based in particular on the realization that not the entire drying section has to be formed with the heating section and therefore, by cleverly forming the flow section through a cylindrical and an annular gap-shaped area, a variant can be created in which the radial center of the heating section can be left out.

[0069] However, a reverse design can also be advantageous, where the heating section is arranged only in the cylindrical interior. For this variant, a heating section design is possible in which the heating section only needs to be designed for a smaller diameter in the printing chamber, which is smaller than the diameter of the entire printing interior.

[0070] According to one aspect, it is proposed that the adsorption material is designed as a granular bulk material with a maximum grain size of up to 12 mm, preferably up to 8 mm, in particular up to 5 mm and / or with a grain size in the range from 1 mm to 12 mm, preferably 1.5 mm to 8 mm and in particular 2 mm to 5 mm and the heating section is designed such that the adsorption material surrounds the medium lines, and in particular the medium lines have heat conducting plates and the adsorption material is also located between the guide plates.

[0071] The adsorption dryer, and thus also the pressure vessel with its heat exchanger or heating section, thus contains such granular adsorption material. The heating section and the adsorption material are coordinated in such a way that the adsorption material essentially completely surrounds the heating section. However, the adsorption material is also arranged in areas of the pressure vessel where no heating section is present. The pressure vessel is thus filled as completely as possible with adsorption material.

[0072] Additionally or alternatively, it is proposed that a distance between adjacent medium lines and / or between adjacent heat-conducting plates be at least 1.2 times the maximum grain size of the adsorption material, and at most five times, preferably at most three times, and in particular at most twice the maximum grain size. This ensures that the adsorption material fits well as a bulk material between the lines or heat-conducting plates, in particular, that it can be poured between them, while simultaneously ensuring good heat input because excessively large distances are avoided.

[0073] Adjacent medium lines can also be understood as two sections of the same medium line, for example, if the line is arranged in a spiral or meandering pattern, so that such two sections are adjacent to each other. It was thus recognized that good heat transfer from the respective medium line or heat conducting plate to the filled granular adsorption material can be achieved if the geometric design of the heat exchanger or its heating section is such that all elements, including the medium lines and, if present, the heat conducting plates, are surrounded by the adsorption material on as many sides as possible, as long as they are free.According to the invention, a compressed gas system for providing dried compressed gas, in particular compressed air, with an adsorption dryer is also proposed, wherein the compressed gas system has a compressor for generating the compressed gas, the compressor is operated using a compressor oil and the heat exchanger is connected to the compressor in order to use the compressor oil or a part thereof as a heat transfer medium.

[0074] It was particularly recognized here that a compressor, which can be operated in a particularly conventional manner, uses compressor oil, which is heated during the compression of the compressed gas, especially when compressing air into compressed air. Such heated compressor oil must be cooled again to prevent overall overheating of the compressor. A further advantage of cooling the oil is that the efficiency of the compressor and thus the compression ratio is increased.

[0075] For this purpose, the compressor oil can be used as a heat transfer medium for the heat exchanger. There, heat from the compressor oil can be transferred to the adsorption material and the regeneration gas, thereby cooling the compressor oil. However, if the heat generated in the compressor oil by the compressor is insufficient, the compressor oil can also be heated further before being fed to the heat exchanger.

[0076] It was particularly recognized that this allows the adsorption dryer to be operated with particularly high energy efficiency. The heat exchanger is adapted to use the compressor oil as the heat transfer medium. In particular, an inner diameter of the medium channel or of the multiple medium channels in the at least one medium line is selected such that the compressor oil, which may be comparatively viscous, can be passed through the heat exchanger.

[0077] According to the invention, a method for operating a compressed gas system is also proposed, which has an adsorption dryer with at least one heat exchanger, wherein the adsorption dryer is provided for drying a compressed gas, in particular compressed air, and has at least one pressure vessel with an adsorption material for adsorbing moisture from the compressed gas that is filled into the pressure vessel, a drying inlet for admitting a compressed gas for drying, a drying outlet for discharging the compressed gas after drying and a drying section through which the compressed gas flows in a drying operation from the drying inlet to the drying outlet, and has at least one heat exchanger, wherein of the at least one heat exchanger, the heating section is arranged in the pressure vessel and the heating section is surrounded by the adsorption material, wherein the adsorption material is designed as a granular bulk material.For this purpose, it is proposed that the adsorption dryer is designed according to one of the aspects described above which are directed towards an adsorption dryer, and / or that the heat exchanger is designed according to one of the aspects explained above which are directed towards a heat exchanger.

[0078] The procedure includes the steps

[0079] Operating the pressure vessel in a drying operation in which the pressurised gas is passed through the pressure vessel from the drying inlet to the drying outlet to release moisture to the adsorption material, and

[0080] Operating the pressure vessel in a regeneration mode in which a regeneration gas, in particular compressed air, in particular dried compressed air, is passed through the drying section, in particular from the drying outlet to the drying inlet, so that the regeneration gas flows through the adsorption material and flows along a heating section of the heat exchanger to absorb moisture from the adsorption material, wherein the heat exchanger is heated with a heat transfer medium in the regeneration mode in order to transfer heat from the heat transfer medium to the regeneration gas and to the adsorption material, wherein in particular compressor oil of a compressor of the adsorption dryer is used as the heat transfer medium.

[0081] The method is thus directed to operating a compressed gas system with an adsorption dryer. Such an adsorption dryer has a heat exchanger arranged in the pressure vessel. The adsorption dryer and / or the heat exchanger can be designed and operated as described above.

[0082] Specifically, it is intended that the pressure vessel be operated in a drying mode and a regeneration mode, namely alternately. Initially, the pressure vessel is operated in the drying mode, in which the compressed gas is passed through the pressure vessel for drying. The adsorption material absorbs moisture from the compressed gas. Subsequently, once the adsorption material has absorbed a sufficient amount of moisture, the pressure vessel is operated in the regeneration mode. The moisture is then removed from the adsorption material by the regeneration gas.

[0083] In this regeneration mode, the heat exchanger is operated, which is particularly inactive during drying mode. However, in regeneration mode, the adsorption material is heated, and thus the regeneration gas is heated both directly and indirectly, allowing it to absorb more moisture, allowing the adsorption material to be dried more effectively.

[0084] For this purpose, the heat exchanger is heated during regeneration mode with the heat transfer medium, which is then passed through the heat exchanger, particularly through the medium lines. It is particularly suggested that the heat transfer medium be compressor oil from a compressor that generates compressed gas for the adsorption dryer. A compressed gas system, which can also be synonymously referred to as a compressed gas generation device, with an adsorption dryer can thus be operated particularly energy-efficiently.

[0085] In particular, at least two pressure vessels are present in such an adsorption dryer, which are operated alternately, so that essentially one pressure vessel is operated in drying mode, while the other pressure vessel is operated in regeneration mode. These operating modes can then alternate for the two pressure vessels. This also allows the compressor oil of the adsorption dryer's compressor to be essentially continuously used to heat a heat exchanger in one of the pressure vessels and thus cool it. For this purpose, it is fed to the heat exchanger whose pressure vessel is operating in regeneration mode.

[0086] The invention is explained in more detail below with reference to the accompanying figures.

[0087] Figures 1 and 2 each show an adsorption dryer in a functional representation.

[0088] Figure 3 is an illustration of the space utilization of a pressure vessel.

[0089] Figures 4 to 12 illustrate various possible embodiments of a heat exchanger.

[0090] Figure 13 illustrates a design of a pressure vessel with an annular gap.

[0091] Figure 14 illustrates another possible form of heat exchanger.

[0092] Figure 1 shows a schematic representation of a compressed gas system 100. The compressed gas system 100 has a compressor 1 and an adsorption dryer 102. The compressor 1, which can also be referred to as a compressor, interacts with an oil cooler 2, an oil separation tank 3, and a compressed air cooler 4, which will be described in more detail below. The compressor supplies compressed air to the adsorption device 102, which is provided between the two valves 5 and 6. The adsorption dryer 102 has two pressure vessels 7 and 8, which can also be referred to as containers for the sake of simplicity. In particular, these two pressure vessels 7 and 8 operate alternately, so that one operates in drying mode and the other in regeneration mode. For this purpose, by appropriately positioning the valves 5 and 6, the compressed gas for drying can be supplied to one of the two vessels 7 and 8 in drying mode.

[0093] Each of the two containers 7 and 8 has an upper part 7a and 8a, respectively, and a lower part 7b and 8b, respectively. Both containers are filled with an adsorption material, indicated as a granular material.

[0094] Both containers 7 and 8 each have a drying inlet 103 and 104, respectively, as well as a drying outlet 105 and 106, respectively. In the embodiment shown, the drying inlets 103 and 104 are located at the bottom, and the drying outlets 105 and 106 are located at the top. During drying operation, the compressed air to be dried flows from bottom to top, and the regeneration air flows from top to bottom.

[0095] The lower part 7b or 8b of the containers 7 or 8 can be heated by means of a heater 16 or 17, respectively, which thus each form a heating device. When compressed air flows in from the drying inlet 103 or 104, it first flows through the heating area, although this is switched off during drying operation, and then through the upper part 7a or 8a. During regeneration operation, the regeneration air flows from top to bottom, thus entering at the drying outlet 105 or 106, first flowing through the upper part 7a or 8a and then the lower part 7b or 8b, which accommodates or can form the heating area. During regeneration operation, the heater 16 or 17 is in operation.

[0096] During drying operation, the dried compressed air flows out either from the drying outlet 105 or the drying outlet 106, depending on which of the two containers 7 and 8 is operating in the drying mode, and flows essentially to the valve 12, which can also be referred to as the outlet valve, and from there to the dryer outlet 13, namely the outlet of the adsorption device 102 as a whole. However, an additional container with adsorption material can be connected to compensate for fluctuations in the humidity level of the dried compressed air, which is provided according to one embodiment but is not shown here for the sake of simplicity.

[0097] At the same time, a portion of the dried compressed air is passed upstream of valve 12 through throttles 10 and 11, one or both of which reduce the pressure of the dried compressed air, in particular to approximately ambient pressure. Which of the two throttles 10 or 11 reduces the pressure, or which carries out a pressure reduction to what extent, depends on which of the two vessels 7 and 8 is in drying mode and which is in regeneration mode. In any case, a portion of the dried compressed air is transferred from the vessel operating in drying mode to the vessel operating in regeneration mode via these two throttles 10 and 11, controlled by the valve 9 arranged between them.

[0098] The vessel operating in regeneration mode thus receives regeneration air at the drying outlet 105 or 106, which flows through the respective vessel 8 or 8, passing through the lower part 7b or 8b, which can be considered the heating area, and finally exits at the drying inlet 103 or 104. From there, the regeneration air can be vented to the environment via the valve 18 or 19 and a downstream silencer 20 or 21.

[0099] A possible embodiment is thus shown in simplified form in Fig. 1. The air is compressed in the compressor 1. Oil, which has been cooled in the oil cooler 2, is injected into the compressor. The warm compressed air-oil mixture is separated in the oil separator tank 3. The compressed air flows from the oil separator tank through the compressed air cooler 4 and is cooled there.

[0100] Likewise, the temperature or a temperature level of the oil can be increased by passing all or part of the oil past the oil heat exchanger 2 of the compressor, in the sense of a bypass, and thus feeding it to the compressor block at a higher temperature.

[0101] A particularly efficient embodiment that utilizes the waste heat from the compression process is shown in Fig. 2. The structure corresponds to that in Fig. 1 with a specific embodiment for the heaters 16 and 17.

[0102] Heaters 16 and 17 can be supplied with warm oil from the compressor by opening valves 14 or 15. If neither heater is active, valves 14 and 15 are closed and valve 22 is opened instead.

[0103] It was recognized that pressure vessels for compressed air applications are usually designed in a round shape, as this allows for relatively thin walls at corresponding operating pressures. This saves, among other things, the cost and weight of the pressure vessels. Since the heat exchanger is positioned within a pressure vessel, it is proposed that the geometry of the heat exchanger be compatible with the pressure vessel. In the area where heating is desired, there should be as few or no areas where only insufficient heat input is possible, e.g., if elements of the heat exchanger are too far away from there. This would impair the efficiency of the regeneration operation. Consequently, the heat exchanger should be able to easily reach all areas to be heated, particularly in the direction perpendicular to the flow.The use of a cuboid heat exchanger within a round pressure vessel is therefore less suitable, as illustrated in Fig. 3.

[0104] Alternatively, areas into which the heat exchanger cannot sufficiently transfer heat could be blocked, i.e., provided with packing or similar, so that they are no longer available for filling with desiccant material, as illustrated by the four gray areas on the sides in Fig. 3. This would incur additional costs due to the packing, and in addition, as a result of the packing, the size of the pressure vessel would have to be increased in order to continue to use a constant amount of desiccant, which was recognized as unfavorable.

[0105] It was recognized that the individual elements of the heat exchanger, especially the medium lines, should be appropriately spaced from one another. If this distance is too great, the heat input into the desiccant flowing through it deteriorates, and regeneration operation becomes less effective at a constant regeneration air flow. If the distance is too small, little space remains between them for the desiccant. Particularly with a desiccant bed in granular form, a distance that is too small between the heat exchanger elements is disadvantageous, as filling or emptying with the granules becomes more difficult, or even the desiccant beads can become jammed, making filling or emptying impossible.

[0106] Suitable values ​​for the distance between individual elements of the heat exchanger start at approximately slightly more than the desiccant diameter or the maximum granule diameter in the case of a polydisperse bed. A sensible upper limit for the distance is approximately two to three times the said diameter, i.e. two or three times the maximum grain size. With distance values ​​above this, heat input is still possible, but this will be comparatively less pronounced. The individual elements of the heat exchanger should have the most suitable geometry possible, in particular a large surface area, in order to achieve a suitable heat input into the surrounding area, i.e. the area through which the desiccant flows, despite the comparatively moderate temperature of the heated oil.

[0107] Ideally, as few elements of the heat exchanger as possible should be continuous in the direction of flow of the regeneration gas, i.e., in the longitudinal direction, especially when using granular desiccant. Such surfaces can be considered additional walls of the bed area. The void ratio of the bed increases toward the wall, reaching a value of 1. This creates a somewhat excessive velocity near the wall, which compromises the adsorption equilibrium between the flowing gas, especially the flowing air, and the desiccant. Consequently, the drying and regeneration properties of the structure deteriorate.

[0108] Due to the increased viscosity of oil compared to, for example, water, appropriate dimensioning of the channels within the heat exchanger is essential to keep the oil pressure drop within a reasonable range. It is recommended that at least one medium channel be selected with this in mind.

[0109] Key aspects of the invention are explained below using exemplary embodiments and the accompanying figures:

[0110] A heat exchanger for a round installation space is proposed, which, as described above, is advantageous for use within a pressure vessel. The heat exchanger is designed in such a way that its interstices can be filled and emptied with desiccant granules, but also that sufficient heat can be introduced into this desiccant filling. The heat exchanger can consist of microchannel profiles that are bent to form a heat exchanger for a round installation space. The advantages of these profiles are described above or arise from the recognized and described disadvantages of the prior art. The heat exchanger can also be designed as a plate heat exchanger. The special design heat exchanger proposed here can also be referred to as a special design heat exchanger because it also takes into account the design of the pressure vessel, which also affects its design.It is also intended for use in novel adsorption drying processes, as described above. A suitable heat exchanger of a special design for use in novel adsorption drying processes is shown in Figure 4. This heat exchanger 1200 is shown in a perspective view and a top view. It has, for example, 12 medium lines 1202 and thus 12 line levels; there may also be 6 or 18, or even more or fewer. The 12 medium lines 1202 are arranged between a supply channel 1204 and a discharge channel 1206. The heat exchanger 1200 shown combines the advantages of suitable integration into a round pressure vessel with the advantages of microchannel profiles, as described above with regard to the aforementioned properties and advantages.By individually specifying the coil pitch, referred to here as the intermediate pitch 1208, the distance between the individual heat exchanger elements, i.e., also between the medium lines or medium line sections, can be set to an optimum. Each turn of one of the spiral-shaped medium lines 1202 can be referred to as a medium line section or, synonymously, as a line section. The intermediate pitch 1208 is then a distance between two medium line sections or between two line sections.

[0111] The intermediate distance 1208 can be at least 6 mm, preferably at least 9 mm, in particular at least 15 mm and / or allow a filling of the granular adsorption material 1280 with a maximum grain size of up to 12 mm, preferably up to 8 mm, in particular up to 5 mm in the intermediate distance 1208.

[0112] Here, the medium lines 1202 are flowed through in parallel, namely from the supply channel 1204 to the discharge channel 1206. Granular adsorption material 1280 is shown as an example, which is intended to completely surround the heat exchanger in the fully equipped pressure vessel into which the heat exchanger 1200 is to be inserted. It is shown here only for illustrative purposes to show that the granular adsorption material is arranged both horizontally and vertically between the medium lines 1202 or the medium line sections 1202 and can thus surround each medium line 1202.

[0113] Figure 4 also shows an enlarged section A, which schematically shows that the granular adsorption material 1280 can also be arranged vertically between the medium lines. The granular adsorption material 1280 can thus also be arranged between line levels 1203. Section A thus shows two of the line levels 1203 with the granular adsorption material 1280 arranged between them. The medium lines 1202 in Figure 4 essentially have a very flat cross-section and are designed as extruded profiles, which makes this cross-sectional shape possible.

[0114] A common manifold for all microchannel profiles as the fluid inlet, i.e., the supply channel 1204, and a common manifold as the fluid outlet, i.e., the discharge channel 1206, enable parallel flow through all medium channels, which can be configured as microchannel channels here and are configured in the medium lines 1202 or form the medium lines 1202. This has a beneficial effect on pressure loss compared to serial flow through all channels, particularly when using oil as the fluid flowing through the channels. In an alternative design, however, the profiles in the manifolds can also be connected in such a way that partial or complete serial flow is possible.

[0115] The collecting pipes can be designed as circular pipes, or in any other design, as shown by way of example in Figure 5. Figure 5 thus shows a plan view of a heat exchanger 1300 with a medium line 1302. A discharge channel 1306 is provided in a form different from that shown in Figure 4.

[0116] Figure 6 shows a plan view of another heat exchanger 1400, with a supply channel 1404 and a discharge channel 1406. To further improve heat input, heat-conducting plates 1410, which can also be referred to as fins or slats, can be provided between the individual turns of the microchannel profile, i.e., medium lines 1402. These plates can be connected in a heat-conducting manner to the microchannel profile on one side or to both sides, as shown in Figure 6. In particular, the heat-conducting plates, slats, or fins are arranged approximately at right angles to the respective microchannel profiles or medium lines, so that they protrude perpendicularly from them. The connection is preferably materially bonded. As described above, care must be taken to ensure a suitable distance between two adjacent heat-conducting plates 1410 or the slats / fins.The use of fins is shown here as an example, but should also be considered optional for the following embodiments. Figure 6 shows the heat-conducting plates 1410 or the fins / fins only for illustrative purposes in a partial area. Preferably, however, they are arranged in a larger area, in particular essentially over the entire distance from the supply channel 1404 to the discharge channel 1406, at least over more than 50% of the distance. The distances between the medium lines or medium line sections of the heat exchanger 1400 can correspond to those explained for the heat exchanger 1200 in Figure 4. Accordingly, granular adsorption material 1480 can be arranged between the medium lines or medium line sections. Figure 6 also shows that the heat-conducting plates 1410 allow the granular adsorption material 1480 to fit between them.The granular adsorption material 1480 and the heat conducting plates 1410 are shown in Figure 6 only as examples for a small area, but they are intended for the entire heat exchanger 1400 or the entire heating area in which the heat exchanger 1400 is to be arranged.

[0117] The profiles can be connected to the manifolds before or after the profiles are formed; for example, the material-to-material joining process of soldering can be used for this purpose.

[0118] A further embodiment is designed such that the collecting pipes are positioned in the outer region of the heat exchanger, as shown in Figure 7. Figure 7 thus shows a heat exchanger 1500 in a perspective view and a top view, with medium lines 1502 between a supply channel 1504 and a discharge channel 1506, which are designed here as collecting pipes.

[0119] A further embodiment is shown in Figure 8 and is designed in such a way that concentric circular rings of microchannel profiles are used to form the medium lines 1602, whose header pipes are interconnected with U-shaped tubes, as shown in Figure 8. Header pipe end faces that are not connected to each other are closed. Figure 8 thus shows a heat exchanger 1600 in a perspective view and a top view, with medium lines 1602 between a supply channel 1604 and a discharge channel 1606 with further header lines 1612, which are designed here as header pipes.

[0120] Another embodiment is designed in such a way that concentric circular rings of microchannel profiles are used to form the medium lines 1702, whose header pipes consist, for example, of extruded double pipes, see Figure 9. This allows for a compact design and positioning of the header pipes in a common area. Figure 9 thus shows a heat exchanger 1700 in a perspective view and a top view, with medium lines 1702 between a supply channel 1704 and a discharge channel 1706, with further header lines 1712, which are designed here as header pipes. An intermediate spacing 1708 between the medium lines 1702 is also shown.

[0121] Another design for a heat exchanger with a special construction can be a meander shape, see Figure 10. The minimum bending radius of the profile must be taken into account during the design. Figure 10 thus shows a heat exchanger 1800 in a perspective view and a top view, with medium lines 1802 between a supply channel 1804 and a discharge channel 1806, which are designed here as manifolds.

[0122] Another embodiment of a heat exchanger of a special design for use in novel adsorption drying processes and the heat exchange therein with the desiccant flowing through can be designed as a finned heat exchanger and is shown in Figure 11. Due to its corresponding design, this heat exchanger 1900 can be used for round installation space cross-sections, with the desiccant being located between the respective heat conducting plates 1910, which are designed here as fins. Figure 11 thus shows a heat exchanger 1900 in a perspective view and a top view, with medium lines 1902 with heat conducting plates 1910. In this embodiment, by way of example, six medium lines 1902 with heat conducting plates 1910 are arranged between a supply channel 1904 and a discharge channel 1906, which are designed here as collecting pipes. There are thus two supply channels 1904 and two discharge channels 1906.

[0123] A heat exchanger of a special design for use in innovative adsorption drying processes, suitable for an annular installation space, is shown in Figure 12 based on the heat exchanger 1200 shown in Figure 4. However, the principle also applies to other heat exchanger designs. Figure 12 thus shows a heat exchanger 2000 in a perspective view and a top view, with medium lines 2002 between a supply channel 2004 and a discharge channel 2006, which are designed here as collecting pipes.

[0124] A heat exchanger designed in this way can be used, for example, for pressure vessels that are ring-shaped or, for example, whose interior is blocked, or divided by a round partition wall that may be coaxial with the vessel axis, as shown in Figure 13. Figure 13 thus shows a pressure vessel 2120 with a cylindrical interior 2122 and an annular gap space 2124, which are separated from one another by a coaxial partition wall 2126. During drying operation, a compressed gas can flow into the annular gap 2124 according to inflow arrow 2131, flow over from the annular gap 2124 into the cylindrical interior 2122 according to bypass arrow 2132, and flow out of the pressure vessel 2120 according to outflow arrow 2133.

[0125] The coaxial partition wall 2126 is connected to the tank 2120 in the lower area and forces flow through the tank, first in one area and then in the separated area. Both areas are connected to each other in the upper part of the pressure vessel, but a tank can also be designed so that the connection between the two areas occurs in the lower part of the vessel. The arrows indicate the flow direction during adsorption, i.e., in drying mode, for the illustrated structure. Regeneration takes place in the opposite flow direction. The annular heat exchanger 2100 of special design is indicated by a dashed line in Figure 13.

[0126] For use in innovative adsorption drying processes and the heat exchange with the flowing desiccant, an annular finned heat exchanger can also be used in such a space, as shown in Figure 14. The desiccant is then located between the respective fins. As described above, it is important to ensure an appropriate spacing between two adjacent fins.

[0127] Figure 14 thus shows a heat exchanger 2200 in a perspective view and a top view, with medium lines 2202 with heat conducting plates 2210. According to this embodiment, 24 medium lines 2202 are provided, two of which are each guided in parallel through a row of heat conducting plates 2210. In an enlargement shown on the right in Figure 14, such a pair of two medium lines 2202 with several heat conducting plates 2210 is schematically shown. Furthermore, Figure 14 shows a supply channel 2204 and a discharge channel 2206, which are designed here as collecting pipes.

Claims

Claims 1. A heat exchanger for placement in a pressure vessel containing a granular adsorption material of an adsorption dryer intended for drying a compressed gas, in particular compressed air, and for transferring heat from a heat transfer medium, in particular oil, to the granular adsorption material, comprising a heating section for transferring heat from the heat transfer medium to the adsorption material, and the heating section comprises a plurality of medium lines (1202, 1402), each having at least one medium channel, for guiding the heat transfer medium in the medium line, wherein the heating section has a substantially cylindrical shape with a longitudinal axis, the medium lines are arranged in the direction of the longitudinal axis in a plurality of line levels, the medium lines are designed and interconnected such that the heat transfer medium can flow through them jointly in parallel and / or in series,adjacent line levels and / or medium lines of adjacent line levels are spaced apart from each other in the direction of the longitudinal axis and the medium lines are designed as extruded profiles., 2. Heat exchanger for arranging in a pressure vessel comprising a granular adsorption material of an adsorption dryer intended for drying a compressed gas, in particular compressed air, and for transferring heat from a heat transfer medium, in particular oil, to the granular adsorption material, with a heating section for transferring heat from the heat transfer medium to the adsorption material, and the heating section comprises a plurality of medium lines, each having at least one medium channel, for guiding the heat transfer medium in the at least one medium channel, wherein the heating section has a substantially cylindrical shape with a longitudinal axis, the medium lines are arranged in the direction of the longitudinal axis in a plurality of line levels, the medium lines are designed and interconnected such that the heat transfer medium can flow through them together in parallel and / or in series, the medium lines are provided with heat conducting plates, and the heat conducting plates are spaced apart from one another such that a bed of granular adsorption material with a maximum grain size of up to 12 mm, preferably up to 8 mm, in particular up to 5 mm is possible between two adjacent heat conducting plates of the same medium line and / or adjacent heat conducting plates of the same medium line are spaced apart by at least 6 mm, preferably at least 9 mm,in particular at least 15 mm apart.

3. Heat exchanger according to one of the preceding claims, characterized in that in each case in one of the line levels exactly one at least partially circumferential line section of a medium line is provided, or at least two line sections of a medium line are arranged parallel to each other, with an intermediate distance between the line sections which is at least 6 mm, preferably at least 9 mm, in particular at least 15 mm and / or which allows a filling of granular adsorption material with a maximum grain size of up to 12 mm, preferably up to 8 mm, in particular up to 5 mm in the intermediate distance and wherein the heating section has a circular shape in each case in one of the line levels, and / or a circular outer contour, and / or at least in sections a spiral shape.

4. Heat exchanger according to one of the preceding claims, characterized in that the heating section for arrangement in a pressure vessel with a circular-cylindrical or annular gap-shaped interior has in each case in one of the line levels a curved outer contour adapted to the interior.

5. Heat exchanger according to one of the preceding claims, characterized in that the at least one medium channel has an average diameter, the medium line to the medium channel has a wall thickness and a ratio between the average diameter of the medium channel and the wall thickness is in the range from 2 to 50, in particular 5 to 25, and / or the wall thickness has a thickness of 0.15 mm to 2 mm, in particular 0.15 mm to 1.5 mm.

6. Heat exchanger according to one of the preceding claims, characterized in that the medium lines each have an elongated cross-section which has a longitudinal dimension in the direction of the longitudinal axis of the heating section and a transverse dimension transverse thereto, wherein the longitudinal dimension is at least 1.5 times, in particular at least twice as large as the transverse dimension, and / or the medium lines each have at least two medium channels running parallel to one another, and at least two of the parallel medium channels are aligned and spaced from one another in the direction of the longitudinal axis.

7. Heat exchanger according to one of the preceding claims, characterized in that the medium lines are designed as extruded profiles, in particular made of aluminum or an aluminum alloy.

8. Heat exchanger according to one of the preceding claims, characterized in that the heating section has a plurality of collecting lines, comprising at least one supply channel for supplying the heat transfer medium and a discharge channel for discharging the heat transfer medium, wherein the supply channel and the discharge channel and optionally further collecting lines are each arranged parallel to the longitudinal axis and the medium lines are each arranged between the supply channel and the discharge channel, so that the heat transfer medium Medium lines flow parallel from the supply channel to the discharge channel.

9. Heat exchanger according to one of the preceding claims, characterized in that in each case two medium lines adjacent to one another in the direction of the longitudinal axis are spaced from one another by a longitudinal distance which designates a free distance between them, wherein the longitudinal distance corresponds to at least a minimum thickness of the medium line, in particular at least twice the minimum thickness of the medium line, and in particular the longitudinal distance is a maximum of five times the value of the minimum thickness of the medium line.

10. Heat exchanger according to one of the preceding claims, characterized in that adjacent medium lines or adjacent medium line sections of the same line level are connected by heat conducting plates and / or several medium lines or several medium line sections are guided parallel to one another transversely through several heat conducting plates by which they are connected, or if the medium lines are designed as extruded profiles, the extruded profiles do not have any heat conducting plates protruding from the extruded profile.

11. Adsorption dryer for drying a compressed gas, in particular compressed air, with at least one pressure vessel with an adsorption material for adsorbing moisture from the compressed gas which is filled into the pressure vessel, a drying inlet for admitting a compressed gas for drying, a drying outlet for discharging the compressed gas after drying, and a drying section through which the compressed gas flows in a drying operation from the drying inlet to the drying outlet, and at least one heat exchanger according to one of the preceding claims, wherein of the at least one heat exchanger, the heating section is arranged in the pressure vessel and the heating section is surrounded by the adsorption material, the adsorption material being designed as a granular bulk material.

12. Adsorption dryer according to claim 1 1, characterized in that the drying section has a first region facing the drying inlet and a second region facing the drying outlet, and the heating section is arranged in the first region and in particular the heating section is not provided in the second region.

13. Adsorption dryer according to claim 1 1 or 12, characterized in that a switching device is provided for switching between the drying operation and a regeneration operation, wherein in the regeneration operation a regeneration gas flows through the pressure vessel and the drying section from the drying outlet to the drying inlet in order to remove moisture from the adsorption material, and the first region is heated, while the second region is not heated or is heated to a lesser extent.

14. Adsorption dryer according to one of claims 11 to 13, characterized in that the pressure vessel has an annular gap space and a cylindrical interior space surrounded by the annular gap space, wherein the annular gap space and the cylindrical interior space are connected to one another in such a way that the compressed gas for drying can flow from the drying inlet via the annular gap space and further via the cylindrical interior space to the drying outlet, and the heating section of the heat exchanger is arranged in the annular gap space, or the compressed gas for drying can flow from the drying inlet via the cylindrical interior space and further via the annular gap space to the drying outlet, and the heating section of the heat exchanger is arranged in the cylindrical interior space.

15. Adsorption dryer according to one of claims 11 to 14, characterized in that the adsorption material is designed as granular bulk material with a maximum grain size of up to 12 mm, preferably up to 8 mm, in particular up to 5 mm and / or with a grain size in the range of 1 mm to 12 mm, preferably 1.5 mm to 8 mm and in particular 2 mm to 5 mm and the heating section is designed such that the adsorption material surrounds the medium lines, and in particular the medium lines have heat conducting plates and the adsorption material is also located between the guide plates, and / or a distance between adjacent medium lines and / or between adjacent heat conducting plates corresponds to at least 1.2 times a maximum grain size of the adsorption material, and at most five times, preferably at most three times and in particular at most twice the maximum grain size.

16. Compressed gas system for providing dried compressed gas, in particular compressed air, with an adsorption dryer according to one of claims 11 to 15, characterized in that the compressed gas system has a compressor for generating the compressed gas, the compressor is operated using a compressor oil, and the heat exchanger is connected to the compressor in order to use the compressor oil or a part thereof as a heat transfer medium.

17. A method for operating a compressed gas system comprising an adsorption dryer with at least one heat exchanger, wherein the adsorption dryer is provided for drying a compressed gas, in particular compressed air, and comprises at least one pressure vessel with an adsorption material for adsorbing moisture from the compressed gas, which is filled into the pressure vessel, a drying inlet for admitting a compressed gas for drying, a drying outlet for discharging the compressed gas after Drying and a drying section through which the compressed gas flows in a drying operation from the drying inlet to the drying outlet, and at least one heat exchanger, wherein of the at least one heat exchanger, the heating section is arranged in the pressure vessel and the heating section is surrounded by the adsorption material, wherein the adsorption material is designed as granular bulk material, and wherein the compressed gas system is designed according to claim 16, the adsorption dryer is designed according to one of claims 11 to 15, and / or the heat exchanger is designed according to one of claims 1 to 10, and the method comprises the steps Operating the pressure vessel in a drying operation in which the pressurised gas is passed through the pressure vessel from the drying inlet to the drying outlet to release moisture to the adsorption material, and Operating the pressure vessel in a regeneration mode in which a regeneration gas, in particular compressed air, in particular dried compressed air, is passed through the drying section, in particular from the drying outlet to the drying inlet, so that the regeneration gas flows through the adsorption material and flows along a heating section of the heat exchanger to absorb moisture from the adsorption material, wherein the heat exchanger is heated with a heat transfer medium in regeneration operation in order to transfer heat from the heat transfer medium to the regeneration gas and to the adsorption material, wherein in particular - compressor oil of a compressor of the adsorption dryer is used as the heat transfer medium.

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