Patent Application
20190030503
The present invention relates to a mixer heat exchanger and to a mixer heat exchanger insert arrangement for a mixer heat exchanger, in particular a mixer heat exchanger and a mixer heat exchanger insert arrangement for a mixer heat exchanger with reduced fouling behavior.
For the mixing of fluids, in particular during processes, both static and dynamic mixers can be used. In the case of dynamic mixers, it is possible, for example, to use stirring elements, which actively stir the fluid to be mixed. In the case of a static mixer, mixing is achieved not through stirring energy introduced externally, but through the energy which is inherent to a flowing fluid. Here the fluid is mixed as a result of the movement of the fluid upon contact with a mixer geometry. For such mixing by means of a static mixer, so-called X mixers, for example, are used, in which structures that are arranged in alternation transversely with respect to one another are introduced in the flow volume and mix a fluid that is flowing though. Such so-called X mixers can, for example, consist of a plurality of bar-shaped flat bodies which, for example, are arranged in alternation at an angle of, for example, 90° with respect to one another. A through-flowing fluid is, in this manner, split and recombined several times, leading to a laminar or turbulent flow, or else forced to change direction, resulting in a turbulent flow which subsequently leads to a mixing of the fluid.
Since mixers of this type are often used in reactors, it is additionally necessary not only to mix the fluid but also at the same time to control the temperature of the fluid. Mixer heat exchangers consisting of several tubes through which a temperature control liquid can be carried are known for this purpose. These pipes, which generally run in the longitudinal direction of a flow channel, are in this case provided with flow guide plates arranged transversely thereto, which bring about mixing of the through-flowing fluid due to the “split and recombine” effect.
Furthermore, heat exchangers are known in which the tubes carrying a temperature control fluid are routed in a meandering manner, with the meandering tubes lying in a plane which lies parallel to the through-flow direction of the fluid in a flow channel.
Mixers and heat exchangers of the type mentioned above are known, for example, from EP 1 067 352 A2 or WO 2008/017571 A1.
The aforementioned heat exchangers and mixers have only a low mixing capacity or, in particular in the case of fluids which have agglomerates, exhibit a tendency for accumulation of agglomerates in regions with acute angles in which the agglomerates or thickened fluid lumps can become lodged, or have flow-calmed regions in which secondary reactions can occur, the products of which can likewise accumulate. This effect is referred to as “fouling”.
Fouling of such type possibly has an adverse effect on the state of the fluid to be mixed and temperature-controlled, so that a settling of agglomerates or thickened fluid lumps should be avoided.
An object of the invention may be regarded as that of providing a mixer heat exchanger and a mixer heat exchanger insert or a mixer heat exchanger insert arrangement, which have a reduced fouling tendency.
The object of the present invention is achieved by the subject matter of the independent claims, with developments of the invention being embodied in the dependent claims.
According to an embodiment of the invention, a mixer heat exchanger insert is provided, comprising a first group of hollow-body plates with an inner volume and a second group of hollow-body plates with an inner volume, the hollow-body plates of the first group being inclined in a first direction in relation to a direction of longitudinal extent of the mixer heat exchanger insert, the hollow-body plates of the second group being inclined in a second direction in relation to a direction of longitudinal extent of the mixer heat exchanger insert, the hollow-body plates of the first group laterally abutting the hollow-body plates of the second group and the inner volumes of the first hollow-body plates being connected to the inner volumes of the second hollow-body plates, so that the inner volumes of the first group and the inner volumes of the second group are part of a connected, total inner volume that is designed to carry a temperature control fluid.
In this way, a mixer heat exchanger insert can be provided which at the same time also provides, as flow guide structures, structures through which a temperature control fluid can be carried. In other words, the structures of the mixer heat exchanger insert serve at the same time as flow guide structures for homogenizing and carrying a temperature control liquid. This in particular eliminates the need for a mixing structure, known for example from EP 1 067 352 A1, in which tubes provided in the longitudinal direction of a flow channel which serve for carrying a temperature control fluid are provided and are additionally penetrated by flow guide plates lying transversely thereto. It is possible, in particular, to avoid agglomerates and thickened fluid lumps settling at the joints between the flow channels of the temperature control fluid and the flow deflection plates, since there is no need for such connections in the case of the mixer heat exchanger insert according to the invention. Such a mixer heat exchanger (insert) or mixer heat exchanger insert arrangement also has a significantly better surface-to-volume ratio in comparison to the mixer heat exchangers described in EP 1 067 352 A1. In particular, the surface-to-volume ratio of the arrangement according to the invention can be higher than that in the arrangement described in EP 1 067 352 A1 by a factor of four.
According to an embodiment of the invention, the first direction and the second direction are diametrically opposite one another.
In this way, it is possible, in the case of an alternating impingement of flow on hollow-body plates inclined in the first direction and on hollow-body plates inclined in the second direction, to bring about a splitting of the fluid flow or else a strong alternating flow deflection, which leads to thorough mixing.
According to an embodiment of the invention, the mixer heat exchanger insert further has a temperature control fluid inlet and a temperature control fluid outlet, a hollow-body plate of the second group laterally abutting at least two hollow-body plates of the first group and, at the two abutment points, the inner volume of the hollow-body plate of the second group being connected to the volumes of the two adjacent hollow-body plates of the first group in such a manner that a temperature control fluid flows via the inner volume of a first hollow-body plate of the first group from the temperature control fluid inlet into the inner volume of the hollow-body plate of the second group, and then via the inner volume of the second hollow-body plate of the first group to the temperature control fluid outlet.
In this way, a structure can be provided in which the temperature control liquid flows in an alternating manner through the hollow-body plates which are alternately inclined in a first direction and a second direction. This particularly enables thorough mixing to be achieved by means of the alternately inclined hollow-body plates, while at the same time the temperature control liquid can also flow in a sequential manner through these hollow-body plates. Here it should be understood that the liquid region of the temperature control fluid which is carried through the individual hollow-body plates is hermetically sealed with respect to an outer region, in which a liquid to be temperature-controlled and to be mixed is carried, so that no unwanted mixing of a liquid to be temperature-controlled and to be mixed and the temperature control liquid occurs.
According to an embodiment of the invention, the hollow-body plates of the first group and the hollow-body plates of the second group are of rib-shaped design, a plurality of rib-shaped hollow-body plates of the first group being arranged at intervals next to one another in a parallel manner in the direction of longitudinal extent and a plurality of rib-shaped hollow-body plates of the second group being arranged at intervals next to one another in a parallel manner in the direction of longitudinal extent, the rib-shaped hollow-body plates of the first group arranged next to one another in a parallel manner and the rib-shaped hollow-body plates of the second group arranged next to one another in a parallel manner being arranged next to one another in a mutually abutting and alternating manner and the inner volumes of the respective rib-shaped hollow-body plates being connected to one another at abutment points.
In this way, several flow channels that are flowed through in a parallel manner can be provided for a temperature control liquid in the hollow-body plates, so that, for example, a temperature control liquid in the mixer heat exchanger insert can be carried in the channels in a mutually independent manner. It is possible, in particular, for two rib-shaped hollow-body plates to be inclined in a first direction and two rib-shaped hollow-body plates to be inclined in the second direction, and for these to be arranged in an alternating manner with respect to one another. Here it should be understood that, in case only a single connected inner volume is to be provided, the rib-shaped hollow-body plates can be connected to one another at all abutment points in such a manner that their inner volumes are each connected to one another. By arranging several such combinations of rib-shaped hollow-body plates, it is possible to provide a stack in which the rib-shaped hollow-body plates are arranged one behind the other in the flow direction.
According to an embodiment of the invention, the mixer heat exchanger insert has a third group of hollow-body plates, the hollow-body plates of the third group being inclined in a third direction in relation to a direction of longitudinal extent of the mixer heat exchanger insert, with the first direction, the second direction and the third direction each being arranged at an angle of 120° with respect to one another.
In this way, a type of propeller arrangement can be achieved by the hollow-body plates arranged in an inclined manner, which plates allow particularly thorough mixing of the fluid to be temperature-controlled and to be mixed.
According to an embodiment of the invention, the inclination angle of the hollow-body plates of the first group in relation to the direction of longitudinal extent and the inclination angle of the hollow-body plates of the second group in relation to the direction of longitudinal extent are equal.
In this way, it is possible to achieve a uniform arrangement of the mutually oblique hollow-body plates, which repeatedly give rise at regular intervals to a flow deflection or a splitting of the fluid to be temperature-controlled and to be mixed, so that a uniform, alternating flow deflection or flow split ensues due to the matching inclination angle in opposing directions.
According to an embodiment of the invention, the hollow-body plates form at least two fluidically separate, parallel total volumes over the direction of longitudinal extent.
This can be achieved, in particular, by the connections of the inner volumes of the hollow-body plates of the first group and of the hollow-body plates of the second group being connected at some abutment points while remaining separate at other points, so that the two fluidically separate, parallel total volumes form. As a result of this, a mixer heat exchanger insert can be provided in which the temperature control liquid flows outwards through one total volume and is carried back via the other total volume, so that the inlet and the outlet of the temperature control liquid can be provided on the same side.
According to an embodiment of the invention, the hollow-body plates of the first group, positioned one under the other, and the hollow-body plates of the second group, positioned one under the other, have a matching spacing in the direction of longitudinal extent of the mixer heat exchanger insert.
In this way, it is possible to achieve that the effective flow cross sections at the parallel intermediate spaces are uniformly configured with regard to a through-flow in the longitudinal direction, so that no artificial bottlenecks form in which a build-up of a liquid to be temperature-controlled can possibly occur. Such a build-up can, for example, lead to an agglomeration or thickening of a liquid to be temperature-controlled and to be mixed, which, in turn, can speed up the fouling process.
According to an embodiment of the invention, the hollow-body plates of the first group and the hollow-body plates of the second group are inclined at an angle of 30° to 60°, in particular at an angle of between 40° and 50°, in relation to the direction of longitudinal extent.
In this way, a good ratio can be set between shearing behavior and flow-calmed regions, so that for the liquid to be temperature-controlled, sufficient mixing is ensured.
According to an embodiment of the invention, the mixer heat exchanger insert is manufactured by a 3D printing process, in particular by an additive production process, in particular by a direct metal-melt laser process (DMLS).
In this way, a mixer heat exchanger insert having a complex structure can be manufactured, the hollow-body plates of which insert are connected at the abutment points in such a manner that the inner volumes of mutually abutting hollow-body plates are connected to one another. A 3D printing process allows complicated production of the individual components and joining of the individual components, for example through soldering or welding, to be avoided, so that a mixer heat exchanger insert according to the invention can be manufactured efficiently and cost-effectively.
According to an embodiment of the invention, a mixer heat exchanger insert arrangement having a plurality of mixer heat exchanger inserts according to the description above is provided, the plurality of mixer heat exchanger inserts being arranged one behind the other with respect to a direction of longitudinal extent and a temperature control fluid outlet of a mixer heat exchanger insert being connected to a temperature control fluid inlet of an adjacent mixer heat exchanger insert in such a manner that the inner volumes are connected at a boundary between two adjacent mixer heat exchanger inserts, so that a temperature control fluid can flow from a mixer heat exchanger insert to an adjacent mixer heat exchanger insert.
In this way, several mixer heat exchanger inserts can be arranged one behind the other in a modular manner. In particular, individual mixer heat exchanger inserts can be produced and, according to requirements, joined to each other in a modular manner. This joining together can be realized, for example, by a welding process, a soldering process or a bonding process. As a result of this, it is possible to ensure at the same time that no leakages with respect to the outer volume, in which the fluid to be temperature-controlled and to be mixed is located, occur at the corresponding temperature control fluid inlets and outlets. It is also possible, however, for several mixer heat exchanger inserts to be printed integrally one behind the other.
According to an embodiment of the invention, the mixer heat exchanger inserts arranged one behind the other are arranged in a rotationally offset manner, in particular with a 90° offset, with respect to the direction of longitudinal extent.
In this way, despite a laminar flow being present, it is possible to achieve the desired mixing of the fluid to be temperature-controlled and to be mixed through the offset arrangement of the mixer heat exchanger inserts and thus also of the hollow-body plates or rib-shaped hollow-body plates.
According to an embodiment of the invention, the hollow-body plates form four fluidically separate, parallel total volumes over the direction of longitudinal extent, the parallel total volumes being connected at one end of the mixer heat exchanger insert arrangement in such a manner that a first and a second of the total volumes are flowed through in a parallel manner with respect to one another by a temperature control liquid and subsequently a third and a fourth of the total volumes are flowed through in a parallel manner with respect to one another and in an anti-parallel manner with respect to the first and the second total volumes.
This can ensure that, even in the case of a mixer heat exchanger insert arrangement consisting of a plurality of mixer heat exchanger inserts, a temperature control fluid inlet and a temperature control fluid outlet can be arranged on the same side, the temperature control liquid being able to flow outwards and then back again with respect to the direction of longitudinal extent.
According to an embodiment of the invention, a mixer heat exchanger is provided having a fluid-carrying volume with a fluid inlet and a fluid outlet, and a mixer heat exchanger insert as described above or a mixer heat exchanger insert arrangement as described above, the mixer heat exchanger insert or the mixer heat exchanger insert arrangement extending into the fluid-carrying volume, so that a fluid flowing through the fluid inlet into the fluid-carrying volume experiences a shear stress due to the geometry of the mixer heat exchanger insert or of the mixer heat exchanger insert arrangement, before the fluid that has flowed in exits the fluid-carrying volume through the fluid outlet.
In this way, a mixer heat exchanger can be provided that ensures reliable temperature control of a fluid to be mixed and to be temperature-controlled and, at the same time, enables sufficient mixing of the fluid.
According to an embodiment of the invention, the fluid-carrying volume has a constant internal cross-sectional area over the direction of longitudinal extent.
In this way, dead or build-up spaces can be avoided and a mixer heat exchanger insert arrangement can, for the purpose of installation, be pushed into the fluid-carrying volume in the longitudinal direction. Constant cross section means that, without an inserted mixer heat exchanger insert, the volume has an unchanging cross-sectional area over a longitudinal extent. Here, an inserted mixer heat exchanger insert can however lead to effective flow cross sections which are no longer strictly constant over the longitudinal extent.
According to an embodiment of the invention, an envelope of the mixer heat exchanger insert as described above has a cross-sectional area that corresponds to the constant internal cross-sectional area of the fluid-carrying volume of the mixer heat exchanger, into which volume the mixer heat exchanger insert is to be introduced.
In this way, accurately-fitted joining together of fluid volume and mixer heat exchanger insert arrangement can be achieved. Expansive empty volumes situated parallel to the mixer heat exchanger insert arrangement can likewise be avoided.
The individual features described above can, of course, also be combined with one another, whereby in some cases it is even possible to achieve advantageous effects which go beyond the sum of the individual effects.
These and other aspects of the present invention are explained and illustrated by reference to the exemplary embodiments that are described hereinafter.
Exemplary embodiments are described below with reference to the following drawings.
It can be seen from
It should be noted that the term “comprise” does not exclude further elements or process steps, just as the term “one” or “a” does not exclude a plurality of elements and steps.
The reference designations that are used serve solely to increase understanding and should in no way be regarded as restrictive, with the scope of protection of the invention being rendered by the claims.
List of reference designations:
| Number | Date | Country | Kind |
|---|---|---|---|
| 16153383.1 | Jan 2016 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/051811 | 1/27/2017 | WO | 00 |
