EP2161525B1 - Modular heat exchanger - Google Patents

Description

The invention relates to a heat exchanger in modular design for plants in which large load and / or temperature fluctuations occur, in particular solar power plants. A heat exchanger according to the preamble of claims 1 and 2 is made GB 653 540 A known.

Out DE 29510720 U1 the applicant is known a heat exchanger, which has proven to be particularly well as a cooling air cooler for gas turbines. This has pipes for the separation of the heat-emitting medium and the heat-absorbing medium. The tubes are arranged meandering between an inlet manifold and an outlet manifold and are flowed through by a heat-absorbing medium. The heat-emitting medium flows around these meandering tubes.

With the help of the DE 29510720 U1 known heat exchanger can be successfully reduced due to the frequent load and temperature changes loads mechanical and thermal nature. Furthermore, the meandering shape of the tube bundles allows a "downsizing" of the heat exchanger at a constant power. Despite the advantages listed, there is still a need for even more compact and more efficient heat exchangers, which can be produced flexibly but nevertheless inexpensively. Heat exchangers for solar power plants, in particular parabolic trough power plants, must also have faster start-up speeds with high temperature gradients.

Therefore, the invention is based on the object DE 29510720 U1 known heat exchanger to improve and specify a heat exchanger, which allows a more compact design, so that even less space is required for the heat exchanger. It is another object of the invention to allow in addition to the reduction of production costs a flexible design.

The object is achieved by a heat exchanger according to the independent claims 1 and 2. Preferred developments are given in the dependent claims.

The heat exchanger according to the invention is modular. The heat exchanger modules, which are at least one preheater, at least one evaporator and at least one superheater module, are arranged in a common outer jacket, in which a heat-emitting medium flows around the heat exchanger modules with the meandering tube bundles: Thus, the heat exchanger combines at least three different apparatuses in one , The heat exchange takes place according to the counter or cross flow principle. The meandering tubes are flowed through by a heat-absorbing medium, for example water. The meandering arrangement of the tube bundles reduces the size of the heat exchanger, improves the heat transfer from the heat-emitting to the heat-absorbing medium and also increases the thermo-elasticity of the structure.

The invention is based inter alia on the finding that the size of the heat exchanger is significantly reduced by the arrangement of the individual heat exchanger modules in a common outer shell with the same or even increased performance of the heat exchanger. Another advantage of the modular design is the possibility of flexible adaptation of individual heat exchanger modules depending on the requirements. Thus, for example, individual modules can be added as needed or only individual modules can be modified, for example, by changing the tube bundle lengths. This eliminates the effort for a comprehensive overall design of the heat exchanger. In addition, production costs can be reduced because common parts or identical modules can be used instead of the cost-intensive individual production of heat exchanger components. By saving additional pipe connections between the individual modules and by the compact design not only material costs are reduced but also increases the efficiency of the heat exchanger, since the heat loss to the environment is effectively reduced thanks to the decrease in the surface, which is in contact with the environment ,

The parallel connection of several evaporator modules by means of a steam drum further increases flexibility and efficiency. In addition, faster start-up can be achieved with higher temperature gradients, which is of enormous importance with changing load and temperature conditions of, for example, solar power plants. According to a preferred embodiment of the invention, the tubes through which the heat-absorbing medium flows from the outlet header of the respective evaporator module to the steam drum are connected to one another, that they have only one common entry into the steam drum. This will continue to reduce material costs and heat loss to the environment.

Likewise, according to a further advantageous embodiment of the invention, the tubes, through which the heat-absorbing medium flows from the steam drum to the inlet header of the respective evaporator module, be interconnected so that they have a single common outlet from the steam drum.

According to the invention, the heat exchanger can be set up either horizontally or vertically. The vertical installation allows even better land use. In this case, several of the heat exchangers according to the invention can be operated side by side in parallel on a relatively small area. In particular solar power plants, the space conditions are unfavorable because the parabolic trough collectors take up a lot of space. The space-saving design of the heat exchanger according to the invention allows an almost location-independent installation, so that the flow paths of the heated media can be shortened to the heat exchanger expedient manner. The temperatures of the heat-emitting medium when entering the heat exchanger are higher, so that the heat yield is better.

The invention provides that the horizontal heat exchanger module has a number of horizontal pipe layers, each pipe layer is formed from an equal number of tubes, and that the tube layers are arranged so that the tubes of the individual tube layers in the vertical direction exactly superimposed are aligned, wherein the flow directions of the heat-absorbing medium in the vertically adjacent, arranged transversely to the central axis of the outer shell pipe sections are opposite. The design of the tube bundles in individual tube layers allows an extremely compact design. The fact that the tubes lie vertically exactly above each other, conventional spacers between the tubes can be used. The opposite flow in the vertically adjacent pipe sections, which are arranged transversely to the central axis of the outer shell, favors the symmetrical temperature distribution in the heat exchanger with respect to the central axis. The same applies to the vertical installation of the heat exchanger. In this case, then the pipe layers are compared to the horizontal lineup rotated by 90 °, vertically next to each other, expediently the preheater module is the lowest in the common outer jacket.

The inlet and outlet collectors preferably have a circular cross section. The tubes of a tube layer are on a circumferential plane of the respective inlet and outlet collector offset from each other by an equal angle with the respective inlet and outlet collector. In this way, the manufacturing process is facilitated because there is enough space for welding, machining or other work on the collectors.

Further preferably, the tubes of the adjacent tube layers are connected to the respective inlet and outlet header, that the tubes of a tube layer with respect to the tubes of the adjacent tube layer are arranged offset by an angle on an adjacent circumferential plane of the respective inlet and outlet collector. As a result, the peripheral surfaces of the input or. Outlet collectors are optimally utilized, so that the arrangement of the tube layers can be made compact. There is still enough space for welding, machining or other work on the collectors.

According to a preferred embodiment of the invention, the tubes of the heat exchanger modules are arranged in a common inner housing, which is arranged concentrically within the outer shell and has an inlet and an outlet opening for the heat-emitting medium. The cross-sectional profile of the inner housing is preferably rectangular, so that the raw bundles are as closely as possible enclosed by this inner housing. The additional enclosure of the heat exchanging components provides further insulation between the heat exchanger modules and the environment. Alternatively, the space between the outer shell and the inner housing can be used as an additional flow channel for the heat-emitting medium. In this way, the residence time of the heat-emitting medium is extended in the heat exchanger, so that the heat transfer to the heat-absorbing medium is improved.

• Fig. 1 einen Längsschnitt durch eine erste Ausführungsvariante mit Darstellung der rohrseitigen Strömungswege bei vertikaler Aufstellung;
• Fig. 2 einen Längsschnitt wie Fig. 1, allerdings mit Darstellung der mantelseitigen Strömungswege;
• Fig. 3 einen Längsschnitt durch eine zweite Ausführungsvariante bei horizontaler Aufstellung;
• Fig. 4 eine Schnittansicht entlang der Linie B-B aus Fig. 3;
• Fig. 5 eine vergrößerte Detailansicht aus Fig. 8;
• Fig. 6 eine Draufsicht von Fig. 5;
• Fig. 7 eine vergrößerte Detailansicht aus Fig. 3;
• Fig. 8 eine Schnittansicht entlang der Linie A-A aus Fig. 3.

The invention will be described in more detail with reference to figures. They show schematically:

• Fig. 1 a longitudinal section through a first embodiment variant showing the pipe-side flow paths in vertical installation;
• Fig. 2 a longitudinal section like Fig. 1 , but with representation of the shell-side flow paths;
• Fig. 3 a longitudinal section through a second embodiment of a horizontal installation;
• Fig. 4 a sectional view taken along the line BB Fig. 3 ;
• Fig. 5 an enlarged detail view Fig. 8 ;
• Fig. 6 a top view of Fig. 5 ;
• Fig. 7 an enlarged detail view Fig. 3 ;
• Fig. 8 a sectional view taken along the line AA Fig. 3 ,

FIG. 1 shows a first embodiment. The heat exchanger 1 is placed vertically in a space-saving manner. In the outer jacket 70 is an inner housing 80, which has a rectangular cross-sectional profile. In the inner housing, the meandering tubes 120 of the individual heat exchanger modules 10, 20, 30, 40, 50 are arranged. The heat-absorbing medium, for example water, enters the inlet header 11 of the preheater module 10 via the pipeline 91. After flowing through the tubes 120 of the preheater module 10, it passes through the outlet header 12 of the preheater module 10 and via the pipe 92 in the steam drum 60. From the steam drum 60, the heated water passes through the pipes 93, 94, 95 in the parallel-connected evaporator modules 20th , 30, 40. Via a common return line 96, the water-vapor mixture from the evaporator modules 20, 30, 40 flows back into the steam drum 60. The steam drum 60 has means (not shown here) for separating the water from the water vapor Mixture, so that the dry steam for overheating via the pipe 97 into the inlet header 51 of the superheater module 50 passes. The now superheated in the superheater module 50 steam passes through the pipe 98 from the heat exchanger and passes, for example, to generate electricity in the downstream turbine.

FIG. 2 shows the same embodiment Fig. 1 , but here the flow path of the heat-emitting medium is shown in more detail. The heat-emitting medium, which in this case is a thermal oil heated by solar energy, enters via the inlet connection 71 of the outer jacket 70 at a temperature of approximately 400 ° C. Via the channel 73, which is formed by the outer jacket 70 and the inner housing 80, the thermal oil enters the inner housing 80, in which the thermal oil, the tubes 120 of the superheater module 50, the three evaporator modules 40, 30, 20 and the preheater module 10 of Flows around in rows and thereby gives off the heat to water. Subsequently, the cooled thermal oil flows through the outlet nozzle 72 from the heat exchanger. 1

FIG. 3 shows a further embodiment of the invention, wherein the heat exchanger 1 is set up horizontally.

In FIG. 4 , the sectional view along the line BB Fig. 3 , the modular design of the heat exchanger 1 is best visible. The preheater module 10 with the inlet header 11 and the outlet header 12 has meandering tubes 120. The construction of the others Heat exchanger modules, namely the evaporator modules 20, 30, 40 and the superheater module 50 is identical. They only differ in their dimensions. The evaporator modules 20, 30, 40, however, are exactly the same. The number of evaporator modules 20, 30, 40 can be adjusted as needed. Since exactly the same parts are used, this results in advantages in terms of manufacturing costs. In addition, one or more defective heat exchanger modules can be easily removed and replaced by new ones in case of faults.

In FIG. 5 an inventive collector is shown enlarged. These are the outlet header 42 of the third evaporator module 40. Essentially, the inlet and outlet header of the various heat exchanger modules differ only slightly from each other. Again, advantages of the modular design can be seen. According to a preferred embodiment, the tubes 101, 102, 103, 104 of a first layer 100 open in a horizontal plane offset by an equal angle α in the collector 42. Likewise open the tubes 111, 112, 113, 114 of a second layer 110 around the same angle α offset in the collector 42nd

FIG. 6 shows a plan view of the collector 42. The angle α, by which a tube of a layer is offset from the next tube of the same position, in this case is in each case 45 °. The second layer 110, which is vertically adjacent to the first layer 100, is offset on the collector 42 relative to the first layer 100 by exactly β = 22.5 °, so that the tubes 111, 112, 113, 114 of the second layer 110 in FIG. 6 each centrally between the tubes 101, 102, 103, 104 of the first layer 100 are visible. By this regularly horizontally and vertically offset arrangement of junctions on the collector 42 remains despite the high compactness always a sufficient distance for welding or other manufacturing steps.

FIG. 7 shows the enlarged detail view "X" Fig. 3 , All tubes of different layers are arranged so that they lie vertically exactly above each other. Due to the horizontal and vertical exact alignment, simple spacers 130 can be uniformly arranged. A further advantage in the arrangement of the tubes 120 in layers is that the flow directions in the vertically adjacent tube sections 210, which are arranged transversely to the central axis 200 of the outer jacket 70, are opposite.

FIG. 8 shows a further advantage of the invention. Due to the adjacent arrangement of the inlet and outlet headers 42, 51 of adjacent heat exchanger modules 40, 50, the overall length of the heat exchanger 1 can be further reduced. Conventionally, the collectors were arranged centrally on the central axis 200 of the heat carrier 1.

The FIGS. 9 and 10 show the structure of the individual pipe layers 100 and 110. In the pipe sections 210, which are arranged transversely to the central axis 200 of the outer shell 70, each tube with respect to its vertically adjacent tube in a horizontal position or with respect to its horizontally adjacent tube in a vertical position an opposite direction the pipe flow on.

Claims (7)

1. A heat exchanger (1) in modular construction, in particular for facilities operated using large load and/or temperature changes, having an external shell (70) and a number of heat exchanger modules, each heat exchanger module, being either a preheater (10), an evaporator (20, 30, 40), or a superheater module (50), comprising an inlet header (11, 21, 31, 41, 51), an outlet header (12, 22, 32, 42, 52), and meandering pipes (120), through which the heat-absorbing medium, in particular water, flows from the inlet header (11, 21, 31, 41, 51) to the outlet header (12, 22, 32, 42, 52), and the heat exchanger modules further being situated inside the shared external shell (70), so that they have the same heat-dissipating medium flowing around them, the evaporator modules (20, 30, 40) being connected in parallel via a steam-collecting drum (60) situated outside the external shell (70), and the heat exchanger (1) being suitable to be set up horizontally or vertically,
   characterized in that
   the heat exchanger module, upon horizontal setup, comprises a number of horizontal pipe layers (100, 110), each pipe layer (100, 110) being formed by an equal number of pipes, and that the pipes of the pipe layers (100, 110) are oriented lying precisely one over another in the vertical direction, the flow directions of the heat-absorbing medium in vertically adjacent pipe sections (210) of adjacent pipe layers (100, 110) situated transversely to the central axis (200) of the external shell (70) being opposite.
2. A heat exchanger (1) in modular construction, in particular for facilities operated using large load and/or temperature changes, having an external shell (70) and a number of heat exchanger modules, each heat exchanger module, being either a preheater (10), an evaporator (20, 30, 40), or a superheater module (50), comprising an inlet header (11, 21, 31, 41, 51), an outlet header (12, 22, 32, 42, 52), and meandering pipes (120), through which the heat-absorbing medium, in particular water, flows from the inlet header (11, 21, 31, 41, 51) to the outlet header (12, 22, 32, 42, 52), and the heat exchanger modules further being situated inside the shared external shell (70), so that they have the same heat-dissipating medium flowing around them, the evaporator modules (20, 30, 40) being connected in parallel via a steam-collecting drum (60) situated outside the external shell (70), and the heat exchanger (1) being suitable to be set up horizontally or vertically,
   characterized in that
   the heat exchanger module, upon vertical setup, comprises a number of vertical pipe layers (100, 110), each pipe layer (100, 110) being formed by an equal number of pipes, and that the pipes of the pipe layers (100, 110) are oriented lying precisely adjacent to one another in the horizontal direction, the flow directions of the heat-absorbing medium in horizontally adjacent pipe sections (210) of adjacent pipe layers (100, 110) situated transversely to the central axis (200) of the external shell (70) being opposite.
3. The heat exchanger according to any one of the preceding claims,
   characterized in that
   the inlet (11, 21, 31, 41, 51) and outlet headers (12, 22, 32, 42, 52) have a circular cross-section, and the pipes (101, 102, 103, 104) of a pipe layer (100) are connected to the respective inlet (41) and outlet header (42) offset to one another by an equal angle (α) on a peripheral plane of the respective inlet (41) and outlet header (42).
4. The heat exchanger (1) according to any one of the preceding claims,
   characterized in that
   the pipes (101, 102, 103, 104, 111, 112, 113, 114) of the adjacent pipe layers (100, 110) are connected to the respective inlet (41) and outlet header (42) in such a way that the pipes (111, 112, 113, 114) of one pipe layer (110) are situated offset by an angle (β) on an adjacent peripheral plane of the respective inlet (41) and outlet header (42) in relation to the pipes (101, 102, 103, 104) of the adjacent pipe layer (100).
5. The heat exchanger according to any one of the preceding claims,
   characterized in that
   the pipes (120) of the heat exchanger modules are situated in a shared internal housing (80) which is situated concentrically inside the external shell (70), and has an inlet and an outlet opening for the heat-dissipating medium.
6. The heat exchanger (1) according to any one of the preceding claims,
   characterized in that
   the pipes (96a, 96b, 96c) through which the heat-absorbing medium flows from the outlet header (22, 32, 42) of the respective evaporator module (20, 30, 40) to the steam-collecting drum (60) are connected to one another in such a way that they have a single shared inlet (96) into the steam-collecting drum (60).
7. The heat exchanger (1) according to any one of the preceding claims,
   characterized in that
   the pipes (93, 94, 95) through which the heat-absorbing medium flows from the steam-collecting drum (60) to the inlet header (21, 31, 41) of the respective evaporator module (20, 30, 40) are connected to one another in such a way that they have a single shared outlet from the steam-collecting drum (60).

Images