SHELL-AND-TUBE HEAT EXCHANGER AND METHOD FOR CHANGING THE TEMPERATURE OF A MEDIUM

Abstract

The invention relates to a shell-and-tube heat exchanger for changing the temperature of a medium, having a plurality of channels of the tubes, an inlet chamber, an outlet chamber, and at least one channel of the shell for a further medium, wherein the medium can be conveyed into the inlet chamber and, from there, through at least a portion of the channels of the tubes into the outlet chamber, and having a closure means arranged on the outlet chamber and designed and adjustable in such a way that outlet openings of each subset of a plurality of different subsets of the channels of the tubes can be closed off. The invention also relates to a method for changing the temperature of a medium by means of a shell-and-tube heat exchanger.

Description

The invention relates to a shell-and-tube heat exchanger for changing the temperature of a medium, and to a method for changing the temperature of a medium by means of a shell-and-tube heat exchanger.

PRIOR ART

For a wide variety of applications, it is necessary to cool or heat media or fluids. For example, in gas generation plants, very high temperatures often occur in the gases and are too high for further use so that they must be cooled. Likewise, in various applications, cooling of gases or gas mixtures may be necessary in order to reduce subsequent compression work.

A conventional technique for cooling or heating media is the use of heat exchangers, in particular so-called shell-and-tube heat exchangers. Shell-and-tube heat exchangers generally have a plurality of tubes, which usually have a very small diameter and are enclosed by a shell in which a channel is formed for the flow of media. A medium to be cooled or heated can then be conveyed through the tubes (i.e., in the channels of the tubes), and the cooling medium or heating medium can be conveyed through the channel of the shell. In particular for cooling a medium, a so-called bypass channel can be provided in order to be able to adjust the temperature after cooling to a desired value. This bypass channel has a larger diameter than the channels of the tubes so that the medium flows faster therein, and the medium therein cools down less. The medium flow in the bypass can then be regulated, for example, by means of a valve or a flap. Such a shell-and-tube heat exchanger is disclosed, for example, in WO 2018/215102 A1.

A disadvantage there is, however, that the temperature of the medium flowing through the bypass channel and the valve thereof is necessarily warmer or hotter than the temperature after mixing with the more strongly cooled medium flowing through the channels of the tubes. In particular in the case of certain synthesis gases as the medium, this can lead to corrosion damage to the valve.

Against this background, the object of the present invention is to provide a possibility to avoid such excessively hot media or locations in a shell-and-tube heat exchanger, but to nevertheless achieve a temperature change, in particular cooling.

This object is achieved by a shell-and-tube heat exchanger and by a method for changing the temperature of a medium by means of a shell-and-tube heat exchanger with the features of the independent claims. Embodiments are the subject-matter of the dependent claims and of the description below.

Advantages of the Invention

The present invention relates to a shell-and-tube heat exchanger for changing the temperature of a medium (or fluid), such as a gas or gas mixture, in particular a synthesis gas, in particular for cooling or heating. Such a shell-and-tube heat exchanger has a plurality of channels of the tubes, an inlet chamber, an outlet chamber, and at least one channel of the shell for a further medium, e.g., a cooling medium. The individual channels of the tubes each have an inlet opening and an outlet opening (the tubes are typically thin tubes which together form a bundle of tubes), wherein the inlet opening is located in an inlet plate or is formed therein, and the outlet openings are correspondingly formed in an outlet plate. The inlet plate thus delimits the inlet chamber, whereas the outlet plate delimits the outlet chamber.

A medium, in particular a medium to be cooled, can, for example, be conveyed through an inlet opening into the inlet chamber and from there through at least a portion of the channels of the tubes into the outlet chamber. From there, the medium, which is, for example, cooled, can then be removed, for example, through an outlet opening or conveyed out of the shell-and-tube heat exchanger. Cooling medium or, where applicable, also heating medium can be conveyed through the channel of the shell, in particular likewise through corresponding inlet and outlet openings. In this way, the medium whose temperature must be changed can be cooled or heated by indirect heat transfer to the cooling or heating medium, which may in particular be water.

Within the scope of the invention, it is now proposed that a closure means arranged on the outlet chamber is provided, which closure means is designed and is adjustable in such a way that the outlet openings of each subset of a plurality of different subsets of the channels of the tubes can be closed off. The different subsets in particular each comprise a different number of channels of the tubes or of corresponding outlet openings. In other words, the closure means is thus able, as desired, to close, for example, a larger or a smaller portion (that is, a larger or a smaller subset) of all the channels of the tubes or the outlet openings thereof. Accordingly, more, or less, of the channels of the tubes are open for the flow of medium, and a higher or lower temperature of the medium is established in the outlet chamber.

The closure means can be designed in such a way that different desired subsets of the outlet openings can be closed off. For this purpose, a certain number of subsets can be predefined, e.g., 10, 20, 30 and 40 of a total of 50 channels of the tubes. However, a nearly continuous specification of subsets, i.e., for example, with an increment of 1 or 2, is also conceivable. In this case, there are hardly any limits on the specific choice, as will be apparent from the following explanations.

A particular advantage of this is that there is no medium flow which is warmer or hotter than the medium present in the outlet chamber. A bypass channel is therefore not necessary. Rather, a greater or lesser number of individual medium flows are simply uniformly cooled. Damage, such as corrosion caused by excessively hot medium, thus also cannot occur to, in particular, sensitive components such as valves. Rather, no sensitive components are necessary at all, as the following explanations will demonstrate.

Preferably, the outlet openings of all the channels of the tubes are formed in an outlet plate with a planar surface. The closure means then has at least one planar closure surface which rests on the surface of the outlet plate and is movable in a plane of the surface. In other words, the at least one closure surface of the closure means can then be moved over or along the surface of the outlet plate. In this way, different subsets, i.e., a different number of outlet openings, can be covered and thus closed off by means of the at least one closure surface as required. In particular, the at least one planar closure surface can then be positioned over the outlet openings of the channels of the tubes to be closed off, in accordance with the channels of the tubes to be closed off. It is conceivable that only one such closure surface is provided; however, the closure means can also be designed in such a way that there are two or more such closure surfaces which then each rest on the surface of the outlet plate. In an expedient embodiment, for example, the at least one planar closure surface is designed as one or more circular sectors. For example, it can be two circular sectors, each with, for example, 900 of the full circumference, which share the same point and are arranged opposite one another. The closure means can then be rotatable, for example by means of an actuator, about an axis of rotation which extends through this shared point and is perpendicular to the surface. A contour of the closure surface can then in particular also be adapted to a grid of the channels of the tubes. In this respect, reference is also made to the figures and the associated description in which such an example is shown.

Alternatively, it is preferred for the closure means to have a plurality of closure pins which can each be inserted into one of the outlet openings. Such closure pins can be rods which have an outer diameter which corresponds to the inner diameter of the channels of the tubes and are, where applicable, also slightly smaller, in order to enable insertion. A conical shape is also conceivable. This plurality of closure pins is in particular designed in such a way that, according to the channels of the tubes to be closed off, it is possible to close off only the outlet openings of the channels of the tubes to be closed off. The outlet openings that are not intended to be closed off are thus not closed with a closure pin.

The outlet openings of all the channels of the tubes can also be formed in this case in an outlet plate with a planar surface. The plurality of closure pins is then expediently arranged on a closure plate which is arranged parallel to the planar surface and can be moved relative to this surface. For example, an actuator can be provided with which the closure plate and thus the closure pins can be moved. This then allows, for example, for the closure pins to be inserted into the channels of the tubes and to close them off. If the closure pins are designed to have different lengths, a desired subset of the outlet openings can thus be closed off. In particular, the plurality of closure pins is then likewise divided into different subsets so that the closure pins of one subset each have the same length, and the closure pins of different subsets each have a different length relative to the closure plate. Thus, for example, the longest closure pins can be inserted into the corresponding channels of the tubes in order to close off the first subset of outlet openings. Upon a further advancement of the closure plate, the second longest closure pins can then also be inserted into the corresponding channels of the tubes in order to close off a second subset of outlet openings, which then includes the first subset. This can be implemented with different subsets as required.

The invention also relates to a method for changing the temperature of a medium by means of a shell-and-tube heat exchanger, i.e., a method for operating a shell-and-tube heat exchanger. The latter has a plurality of channels of the tubes, an inlet chamber, an outlet chamber, and at least one channel of the shell, wherein a medium is conveyed into the inlet chamber and from there through at least a portion of the channels of the tubes into the outlet chamber. According to the change in temperature, a closure means arranged on the outlet chamber is then adjusted in such a way that the outlet openings of each subset of a plurality of different subsets of the channels of the tubes can be closed off therewith. With regard to further embodiments and advantages, reference is at this point made to the above statements regarding the shell-and-tube heat exchanger, which apply accordingly here.

The invention is explained in more detail below with reference to the accompanying drawings, which show various installation parts using which the measures according to the invention are explained.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 schematically shows a shell-and-tube heat exchanger according to the invention in a preferred embodiment.

FIGS. 2a, 2b, 2c and 2d show a portion of a shell-and-tube heat exchanger according to the invention in a preferred embodiment in different views.

FIGS. 3a and 3b show a portion of a shell-and-tube heat exchanger according to the invention in a further, preferred embodiment.

DETAILED DESCRIPTION OF THE DRAWING

In FIG. 1, a shell-and-tube heat exchanger 100 according to the invention is schematically shown in a sectional view in a preferred embodiment, which can be used for changing the temperature of a medium a, such as a synthesis gas which is supplied to the shell-and-tube heat exchanger 100, in particular, for cooling it. The basic principle of the shell-and-tube heat exchanger 100 here corresponds to a traditional shell-and-tube heat exchanger, as is also described in principle in the document cited at the outset.

The shell-and-tube heat exchanger 100 has a plurality of tubes or channels 110 of the tubes through which a medium a to be cooled is conveyed or routed. The channels 110 of the tubes are arranged in this case, by way of example, about a central axis R. For this purpose, the medium a is first supplied via an inlet opening 122 to an inlet chamber 120 and, from there, is conveyed through the channels 110 of the tubes into an outlet chamber 130. Via the outlet chamber 130, the medium can then be conveyed out of the shell-and-tube heat exchanger 100 again via an outlet opening 132. On the inlet chamber 120, the channels 110 of the tubes, or the tubes, are held in position by means of an inlet plate 124; on the outlet chamber 130, they are held by means of an outlet plate 134. In the inlet plate 124, the individual channels 110 of the tubes, or the tubes, have inlet openings or inlet orifices 126; in the outlet plate 134, they have corresponding outlet openings or outlet orifices 136.

The channels 110 of the tubes are surrounded by a shell 140. In the shell 140, a channel 142 of the shell is formed, through which a (further) medium b, in particular a cooling medium such as water, can be conveyed. For this purpose, the medium b can be introduced into the channel 142 of the shell through one or more inlet openings 146, which can be formed, for example, in the form of inlet nozzles (only one inlet opening is shown here by way of example). The medium b can then flow through the channel 142 of the shell and exit through one or more outlet openings 144, which can be formed, for example, in the form of outlet nozzles, out of the channel 142 of the shell (only one outlet opening is shown here by way of example).

The inlet openings 146 are distributed, for example, over the length of the shell-and-tube heat exchanger 100. The outlet openings 144 are, for example, likewise distributed over the length of the shell-and-tube heat exchanger 100. Usually, more medium b is supplied and discharged close to the inlet chamber 120, i.e., where the medium a is still warm. However, the specific embodiment of the channel of the shell or the way in which medium is conveyed therein is not relevant to the present invention.

Furthermore, a closure means 150 is provided on the outlet chamber 130 or arranged there and can close off portions or certain subsets of the outlet openings 136 of the channels 110 of the tubes. By way of example, the outlet openings 136 situated at the bottom in the sectional view are closed off, but the outlet openings 136 at the top are not. In this way, for example, half of all channels 110 of the tubes can be closed off in order to cool the medium a less than would occur in a situation in which all channels 110 of the tubes are open.

For the closure means 150, which may, for example, be a plate or a closure plate, or which may have such a plate, an actuator 154 is provided by way of example, by means of which the closure plate can be rotated in order to close a different subset of outlet openings 136. For this purpose, the actuator 154 can be controlled, for example, by means of a control device 156. For a more detailed description of the closure means 150 and its mode of operation, also in various embodiments, reference is made to the following figures with the associated description.

In FIGS. 2a, 2b, 2c and 2d, a portion of a shell-and-tube heat exchanger according to the invention is shown in various views in a preferred embodiment. The basic structure of the shell-and-tube heat exchanger can correspond to that of FIG. 1. In FIG. 2a, a portion of the outlet plate 134 and some of the channels of the tubes or outlet openings 136 therein are shown in a sectional view comparable to FIG. 1 (see also the axis R). It should be noted that the number of channels of the tubes or outlet openings 136 deviates from that in FIG. 1; however, this is not relevant for the explanation of the invention. In addition, a closure means 250 is shown, which is basically comparable to the closure means 150 indicated in FIG. 1.

FIG. 2b shows a frontal view toward the outlet plate 134 or its surface 238, shown from the outlet opening 132 (see FIG. 1). In this case, a hatching (crossed lines) indicates two regions in which the outlet openings 136 are arranged (the individual outlet openings are not shown here). These two regions correspond to two circular sectors, each with an angle of 90°, the shared point of which lies on the axis R. The two circular sectors are opposite one another, i.e., are uniformly offset from one another, as viewed in the circumferential direction.

In FIGS. 2c and 2d, to expand upon FIG. 2b, the closure means 260 is additionally shown. The closure means 250 has a closure plate 260 which, by way of example, has two planar closure surfaces 262 facing the outlet openings 136. These two closure surfaces 262 are each designed as circular sectors, each with an angle of 90°, the shared point of which lies on the axis R. They lie on the surface 238 of the outlet plate 136 and can be rotated about their shared point or the axis R, for example by means of an actuator 254 (see FIG. 2a).

In the position of the closure means 250 shown in FIG. 2c, none of the outlet openings 136 is closed off. In the position of the closure means 250 shown in FIG. 2d, the closure means is somewhat rotated and some of the outlet openings 136, i.e., a certain subset T thereof, are closed off. They are covered by the closure means or the closure surfaces 262. By rotating the closure means 250, different subsets of the outlet openings 136 can thus be covered or closed off, with different numbers of outlet openings in each case.

By means of a targeted arrangement of the channels of the tubes or the outlet openings thereof and the formation of the closure means, the subsets in this case can be selected individually. It is understood that the specific shape of the closure surfaces, and accordingly the arrangement of the outlet openings, can also be selected differently. A semicircular closure surface (i.e., a circular sector with 180°) is conceivable, for example. However, for example, (only) one closure surface as a circular sector with 90° is conceivable, with the outlet openings arranged in the form of a circular sector with 270°. Although only a maximum of one third of the outlet openings can then be closed off, this may be sufficient, for example, according to the application. Geometries of the closure surfaces deviating from circular segments, which are adapted, for example, to the grid of the channels 110 of the tubes, are also conceivable.

FIG. 3a is a portion of a shell-and-tube heat exchanger according to the invention in a further preferred embodiment. The basic structure of the shell-and-tube heat exchanger can correspond to that of FIG. 1. FIG. 3 shows only a portion of the outlet plate 134, and some of the channels of the tubes or outlet openings 136 therein, in a sectional view comparable to that of FIG. 1 (see also the axis R). It should be noted that the number of channels of the tubes or outlet openings 136 deviates from that in FIG. 1; however, this is not relevant for the explanation of the invention.

In addition, a closure means 350 is shown which has a closure plate 360 on which a plurality of closure pins 362 is arranged. The closure pins 362 are oriented parallel to the axis R and are designed, for example, with a rod shape or, where applicable, conically tapering (with slightly decreasing diameter from the right to the left as seen in FIG. 3). It should be noted here that a diameter of the closure pins can be slightly smaller than a diameter of the corresponding channels of the tubes in order to enable a displacement. Sealing due to high flow resistance is thus nevertheless possible.

Each of the closure pins is thus assigned to an outlet opening 136 and can be inserted into the latter. This is done by displacing the closure plate, for example by means of an actuator 354, along the axis R. The closure pins 362 can thus be brought into and out of the outlet openings 136 or the channels of the tubes.

As can be seen in FIG. 3a, the closure pins 362 are of different lengths, as viewed in the direction of the axis R. This makes it possible, according to the position of the closure plate along the axis R, to close off a different number or subset T of the outlet openings. In the example shown, the two outlet openings next to the axis R, and also the two outlet openings following below them, are closed off. The last four outlet openings at the bottom (in the view in FIG. 3) are not closed off.

FIG. 3b shows a frontal view toward the outlet plate 134 or its surface 238, from the outlet opening 132 (see FIG. 1). The seven rows, as seen downward from the axis R (in FIG. 3a), are seen here from the center (the two middle rows in the common center) outward. By way of example, the arrangement here is non-circular but along the edges of a hexagon.

If the closure plate 360 with the closure pins 362 is now moved further in the direction of the outlet plate 134, the fourth outlet opening from the bottom (or the fourth row of the outlet openings from the outside according to FIG. 3b) is then the next to be closed off. Thereafter, the third outlet opening from the bottom is also closed off. If, on the other hand, the closure plate 360 with the closure pins 362 is moved away from the direction of the outlet plate 134 (starting from the situation in FIG. 3), then the fifth outlet opening from the bottom, and thereafter the sixth outlet opening from the bottom, and finally all the outlet openings are opened.

In this way, certain subsets of the outlet openings, which are closed off one after the other by the displacement of the closure means 360, can thus be specified as desired. For this purpose, it is only necessary to select the length of the closure pins 362 accordingly. Closure pins with the same length close the outlet openings assigned to them, at the same time. Depending on requirements, such closure pins with the same length can be arranged, for example, rotationally symmetrically with respect to the axis R.

It is conceivable, as is also shown here, that certain outlet openings may not be closed off at all, for example because the closure plate 360 does not cover all the outlet openings. It is also conceivable that, when the closure plate 360 rests on the outlet plate 134, outlet openings are closed off without closure pins.

Claims

1. A shell-and-tube heat exchanger for changing the temperature of a medium, having a plurality of channels of the tubes, an inlet chamber, an outlet chamber, and at least one channel of the shell for a further medium, wherein the medium can be conveyed into the inlet chamber and, from there, through at least a portion of the channels of the tubes into the outlet chamber, wherein a closure means arranged on the outlet chamber and designed and adjustable in such a way that outlet openings of each subset of a plurality of different subsets of the channels of the tubes can be closed off.

2. The shell-and-tube heat exchanger according to claim 1, wherein the outlet openings of all channels of the tubes are formed in an outlet plate with a planar surface, and wherein the closure means has at least one planar closure surface which rests on the surface of the outlet plate and is movable in a plane of the surface.

3. The shell-and-tube heat exchanger according to claim 2, wherein the at least one planar closure surface can be positioned over the outlet openings of the channels of the tubes to be closed off, in accordance with the channels of the tubes to be closed off.

4. The shell-and-tube heat exchanger according to claim 2, wherein the at least one planar closure surface is designed as one or more circular sectors.

5. The shell-and-tube heat exchanger according to claim 2, wherein a contour of the closure surface is adapted to a grid of the channels of the tubes.

6. The shell-and-tube heat exchanger according to claim 1, wherein the closure means comprises a plurality of closure pins, each of which can be introduced into one of the outlet openings.

7. The shell-and-tube heat exchanger according to claim 6, wherein the plurality of closure pins is designed in such a way that, according to the channels of the tubes to be closed off, it is possible to therewith close off only the outlet openings of the channels of the tubes to be closed off.

8. The shell-and-tube heat exchanger according to claim 6, wherein the outlet openings of all channels of the tubes are formed in an outlet plate with a planar surface, and wherein the plurality of closure pins is arranged on a closure plate which is arranged parallel to the planar surface and is movable relative to this surface.

9. The shell-and-tube heat exchanger according to claim 8, wherein the plurality of closure pins is divided into different subsets so that the closure pins of one subset each have the same length and the closure pins of different subsets each have a different length relative to the closure plate.

10. A method for changing the temperature of a medium by means of a shell-and-tube heat exchanger having a plurality of channels of the tubes, an inlet chamber, an outlet chamber, and at least one channel of the shell for a further medium, wherein the medium is conveyed into the inlet chamber and from there through at least a portion of the channels of the tubes into the outlet chamber, wherein a closure means arranged on the outlet chamber is adjusted according to the change in temperature in such a way that outlet openings of each subset of a plurality of different subsets of channels of the tubes are closed off therewith.

11. The method according to claim 10, wherein a shell-and-tube heat exchanger is used, the shell-and-tube heat exchanger for changing the temperature of a medium, having a plurality of channels of the tubes, an inlet chamber, an outlet chamber, and at least one channel of the shell for a further medium, wherein the medium can be conveyed into the inlet chamber and, from there, through at least a portion of the channels of the tubes into the outlet chamber, wherein a closure means arranged on the outlet chamber and designed and adjustable in such a way that outlet openings of each subset of a plurality of different subsets of the channels of the tubes can be closed off.