EP1811256B1 - Heat exchange installation - Google Patents

Description

The present invention relates to a heat exchange system between fluids, for cooling a first fluid by heat exchange with a second fluid.

Heat exchange systems are known which comprise a sealed enclosure in which is placed a bundle of plates arranged parallel to each other. The document EP-A-1 153 653 discloses such an installation.

Plates made of thin sheet, most often made of stainless steel, have edges with a smooth surface and a central part provided with corrugations by means of which they are in contact with one another and by which they delimit channels forming contact circuits. circulation of independent fluids.

This type of plate bundle heat exchanger operates with various fluids, such as liquids or gases or a biphasic mixture.

With this type of plate heat exchanger in which the two fluids circulate in the respective circuits, there is a heat exchange between these two fluids which allows to heat one of the fluids and to cool the other fluid or vice versa.

For some industrial applications, it is necessary to obtain a significant temperature difference of the fluid to be cooled between its inlet and its outlet of the plate heat exchanger.

This is why several plate heat exchangers are, in this case, placed one after the other and each plate heat exchanger consists of a sealed chamber in which is disposed a bundle of plates delimiting two independent circuits. The circuits of the various bundles of plates are interconnected by connecting lines which pass through each chamber in a sealed manner so as to achieve a continuous flow of the main fluid in the various bundles of plates.

Therefore, the floor area required for this kind of installation is important and the cost for its manufacture and maintenance is also important.

In addition, the connecting lines between the different exchangers for the transfer of fluids between these exchangers constitute unnecessary and parasitic pressure drop zones and constitute areas of loss of calories thereby decreasing the efficiency of the heat exchange system.

To overcome these drawbacks, thermal exchange systems are known which comprise a sealed enclosure in which are arranged several bundles of plates each connected to means of arrival and discharge of the fluids.

Generally, the plate bundles are rigidly connected to the sealed enclosure which poses problems when the temperature differential between the two fluids is important, for example, of the order of several hundred degrees.

Indeed, this difference in temperature causes in the plate bundles significant thermal stresses that can cause deformations in the plates of the plate bundles and breaks in the welds which reduce the efficiency of the installation.

The object of the invention is to avoid these drawbacks by proposing a compact heat exchange installation and which makes it possible to perform a heat exchange between fluids having a large temperature difference.

The subject of the invention is therefore a heat exchange installation between fluids, of the type comprising a vertical and elongated sealed enclosure, means for heat exchange between the fluids and means of arrival and evacuation. a first and a second fluid, characterized in that the heat exchange means comprise bundles of plates each formed of a stack of horizontal plates delimiting between them two circulation circuits of the two fluids against the current and distributed in star around a tubular central collector, concentric with the enclosure and in that each bundle of plates has a front vertical wall fixed on the central collector and provided with inlets and outlets for each of said fluids and a free rear vertical wall provided with inputs and outputs from each of these fluids, each plate bundle being in sliding abutment on a support member integral with the enclosure.

• les entrées et les sorties des fluides ménagées sur la paroi avant sont formées, pour chaque circuit, par une superposition alternée d'extrémités ouvertes et fermées, les extrémités ouvertes des entrées du circuit pour le premier fluide étant situées au centre de la paroi avant et les extrémités ouvertes des sorties du circuit pour le second fluide étant situées sur les bords latéraux de cette paroi avant,
• les extrémités ouvertes des entrées du premier fluide débouchent dans le collecteur central relié aux moyens d'arrivée de ce premier fluide,
• les extrémités ouvertes des sorties du second fluide des bords latéraux des parois avant des deux faisceaux de plaques adjacents sont reliées entre elles par un collecteur annulaire concentrique audit collecteur central et comportant, à sa partie inférieure, une calotte sphérique reliée aux moyens d'évacuation de ce second fluide,
• les entrées et les sorties des fluides ménagées sur la paroi arrière sont formées, pour chaque circuit, par une superposition alternée d'extrémités ouvertes ou fermées, les extrémités ouvertes des entrées du circuit pour le second fluide étant situées au centre de la paroi arrière et les extrémités ouvertes des sorties pour le premier fluide étant situées sur les bords latéraux de cette paroi arrière,
• les entrées et les sorties des fluides ménagées sur la paroi arrière sont formées, pour chaque circuit, par une superposition alternée d'extrémités ouvertes ou fermées, les extrémités ouvertes des entrées du circuit pour le second fluide étant situées sur les bords latéraux de la paroi arrière et les extrémités ouvertes des sorties pour le premier fluide étant situées au centre de cette paroi arrière,
• les extrémités ouvertes des entrées du second fluide débouchent dans l'espace annulaire entre le collecteur central et l'enceinte, ledit espace annulaire étant relié aux moyens d'arrivée de ce second fluide,
• les extrémités ouvertes des sorties du premier fluide sont coiffées par un collecteur relié par une conduite munie d'au moins un compensateur de dilatation, à un anneau collecteur raccordé aux moyens d'évacuation du second fluide, et
• chaque faisceau de plaques comporte sur chacune de ses parois latérales, un déflecteur vertical s'étendant en direction du faisceau de plaques adjacent, les bords libres des deux déflecteurs contigus se chevauchant.

According to other features of the invention:

• the inlets and outlets of the fluids formed on the front wall are formed, for each circuit, by an alternate superposition of open and closed ends, the open ends of the inputs of the circuit for the first fluid being located in the center of the front wall and the open ends of the outputs of the circuit for the second fluid being located on the lateral edges of this front wall,
• the open ends of the first fluid inlets open into the central manifold connected to the inlet means of this first fluid,
• the open ends of the outlets of the second fluid of the lateral edges of the front walls of the two bundles of adjacent plates are connected to each other by an annular collector concentric with said central collector and comprising, at its lower part, a spherical cap connected to the evacuation means of this second fluid,
• the inlets and outlets of the fluids formed on the rear wall are formed, for each circuit, by an alternating superposition of open or closed ends, the open ends of the inputs of the circuit for the second fluid being located in the center of the rear wall and the open ends of the outlets for the first fluid being located on the lateral edges of this rear wall,
• the inlets and outlets of the fluids formed on the rear wall are formed, for each circuit, by an alternate superposition of open or closed ends, the open ends of the inputs of the circuit for the second fluid being located on the lateral edges of the wall rear and the open ends of the outlets for the first fluid being located in the center of this rear wall,
• the open ends of the inlets of the second fluid open into the annular space between the central collector and the enclosure, said annular space being connected to the inlet means of this second fluid,
• the open ends of the outlets of the first fluid are capped by a manifold connected by a pipe provided with at least one expansion compensator, to a collecting ring connected to the means for discharging the second fluid, and
• each plate bundle has on each of its lateral walls, a vertical baffle extending towards the adjacent bundle of plates, the free edges of the two contiguous baffles overlapping.

• la Fig. 1 est une vue schématique en coupe longitudinale d'une installation d'échange thermique, conforme à l'invention,
• la Fig. 2 est une vue schématique en coupe transversale selon la ligne 2-2 de la Fig. 1,
• la Fig. 3 est une vue schématique en coupe longitudinale selon la ligne 3-3 de la Fig. 2, montrant la circulation des fluides dans l'installation, conforme à l'invention,
• la Fig. 4 est une vue schématique en perspective montrant la répartition des faisceaux de plaques dans l'installation d'échange thermique, conforme à l'invention, et
• les Figs.5A et 5B sont des vues des parois respectivement avant et arrière d'un faisceau de plaques.

The features and advantages of the invention will become apparent from the following description, given by way of example and with reference to the appended drawings, in which:

• the Fig. 1 is a schematic view in longitudinal section of a heat exchange installation, according to the invention,
• the Fig. 2 is a schematic cross-sectional view along line 2-2 of the Fig. 1 ,
• the Fig. 3 is a schematic view in longitudinal section along the line 3-3 of the Fig. 2 , showing the circulation of fluids in the installation, according to the invention,
• the Fig. 4 is a schematic perspective view showing the distribution of the bundles of plates in the heat exchange system according to the invention, and
• the Figs.5A and 5B are views respectively of the front and rear walls of a bundle of plates.

In the figures, there is shown an installation for performing a heat exchange between a first fluid A, said hot fluid, which has on arrival in this installation a temperature of about 800 ° C and a second fluid B, said cold fluid, which has on arrival in said installation a temperature of about 200 ° C.

This heat exchange installation is intended for example to cool the first fluid A by the second fluid B.

The heat exchange installation shown in the figures comprises a watertight enclosure 1 of elongated shape and section for example circular. This sealed enclosure 1 is provided with support members, no shown, intended to rest on a receiving surface and this sealed chamber 1 is preferably arranged vertically.

The chamber 1 comprises a cylindrical central portion 2 provided with a cover 3 and a bottom 4, for example of hemispherical shape.

The installation comprises a central collector 10 tubular and concentric with the chamber 1 and defining with this chamber 1 an annular space 5. This collector 10 has a central portion 11 of generally cylindrical shape provided with a cover 12 and a bottom 13 each having the shape of a spherical cap.

At the level of the cover 12 of this manifold 10 opens means for the arrival of the first fluid A which consist of at least one tubing 14 passing through the cover 3 of the sealed enclosure 1 and provided with at least one expansion compensator 15. The annular space 5 delimited between the central collector 10 and the sealed enclosure 5 is connected to means for supplying the second fluid B which are formed by at least one tubing 16 passing through the cover 3 of this sealed enclosure 1.

As shown in particular in Figs. 1 , 2 and 4 , the installation comprises means of heat exchange between the fluids A and B which comprise bundles of plates 20 arranged in the annular space 5 formed between the central collector 10 and the sealed enclosure 1.

In the exemplary embodiment shown in these figures, the plate bundles 20 are distributed in a star around the central collector 10 and are not, for example, eight in number. In known manner, each plate bundle 20 has a generally parallelepipedal shape and is formed by a stack of horizontal plates 21, metal, thin and for example stainless steel. These plates 21 are provided with corrugations, not shown. The plates 21 of each bundle of plates 20 delimit between them two circulation circuits, respectively for the fluids A and B, against the current.

As shown in particular in Figs. 2 and 4 each plate bundle 20 has a front vertical wall 22 fixed to the central portion 11 of the collector 10, a rear vertical wall 23 free and opening into the annular space 5 and two side walls 24 extending perpendicularly to said central portion 11 of the collector 10.

As shown in Fig. 4 , each plate bundle 20 rests, at its lower part, on a support member 25 integral with the sealed enclosure 1. Each support member 25 is formed by a horizontal plate 25a on which the lower part of the beam slides. corresponding plates 20 and a vertical plate 25b extending perpendicularly to said horizontal plate 25a.

As shown in Fig. 5A , the front wall 22 is provided with inputs and outputs for the fluids A and B which are formed, for each circuit, by an alternating superposition of open ends 26a and 26b, respectively for the first fluid A and for the second fluid B, or closed 27a and 27b respectively for the first fluid A and the second fluid B.

The open ends 26a of the inputs of the circuit for the first fluid A are located in the center of the front wall 22 and the open ends 26b of the outputs of the circuit for the second fluid B are located on the lateral edges of this front wall 22. The ends open 26a of the first fluid A open into the central collector 10 and are, therefore, connected to the inlet manifold 14 of said first fluid A.

The open ends 26b of the outlets of the second fluid B from the lateral edges of the front walls 22 of two adjacent plate bundles 20 are interconnected, as shown in FIGS. Figs. 3 and 4 by an annular collector 30 concentric with the central collector 10.

This annular collector 30 comprises, at its lower part, a hemispherical cap 31 surrounding the bottom 13 of the central collector 10. This hemispherical cap 31 is connected to the means for discharging the second fluid B which consist of at least one tubing 32 passing through the enclosure 1 at its lower part, as shown on the Figs. 1 and 3 . This tubing 32 is provided with at least one expansion compensator 33.

As shown in Fig. 5B , the rear wall 23 of each plate bundle 20 has inputs and outputs for each of the fluids and which are formed for each circuit by an alternating superimposition open ends 28a and 28b, respectively for the first fluid A and the second fluid B, or closed ends 29a and 29b respectively for the first fluid A and the second fluid B.

In the exemplary embodiment represented on this Fig. 5B , the open ends 28b of the inputs of the circuit for the second fluid B are located in the center of the rear wall 23 and the open ends 28a of the outlets for the first fluid A are located on the lateral edges of this rear wall 23. The open ends 28b of the inputs of the second fluid B open into the annular space 5 formed between the collector 10 and the sealed chamber 1 which itself communicates directly with the tubing 16 of the second fluid B in this annular space 5.

As shown on the Figs. 3 and 4 the open ends 28a of the first fluid A outlets are capped by a vertical manifold 35. Therefore, each vertical row of open ends 28a of the first fluid A outlets is capped by the manifold 35 and each manifold 35 is extended, at its upper part, by at least one pipe 36 provided with at least one expansion compensator 37. Each pipe 36 is connected to a collector ring 40 itself connected to the means for discharging the first fluid A which are formed by at least one pipe 41 passing through the cover 3 of the sealed enclosure 1.

According to a variant, not shown, the open ends 28b of the inputs of the second fluid B may be located on the lateral edges of the rear wall 23 and the open ends of the outlets 28a for the first fluid A may be located in the center of this rear wall. 23. In this case, the vertical row of the open ends 28a of the outlets for the first fluid A of each plate bundle 20 is capped by a manifold 35 connected by a pipe 36 to the collector ring 40.

As represented in Fig. 2 each plate bundle 20 has, on each of its sidewalls 24, a vertical baffle extending in the direction of the adjacent plate bundle.

The free edges 45a of two adjacent deflectors overlap so as to let the second fluid B and to create around the central collector 10, a buffer zone of the second fluid B.

A deflector 46 is placed around the inlet pipe 14 of the first fluid A and a deflector 47 is also placed below the bundles of plates 20 between the hemispherical cap 31 of the central collector 10 and the bottom 4 of the sealed enclosure 1.

Referring now to the Fig. 3 we will describe the circulation of fluids A and B in the installation.

The first hot fluid A which is at a temperature of the order of 800 ° C enters through the inlet pipe 14 into the central collector 10, then is directed into the inlets 26a of each of the plate bundles 20 .

The second fluid B which is at a temperature of the order of 200 ° enters through the inlet pipe 16 into the annular space 5 formed between the central collector 10 and the sealed enclosure 1. This second fluid B is directed towards the inputs 28b of the rear wall 23 of each of the plate bundles 20. The circulation of the fluids A and B in the independent circuits of each of the bundles of plates 20 causes a heat exchange between these fluids and the first fluid A thus cooled, after having passed through each of the bundles of plates 20, exits from the end ends 28a of the bundles of plates 20, and is then collected by the vertical manifolds 35. This cooled first fluid A passes through the conduits 36 and enters the collector ring 40 before being evacuated from the installation by the tubing 41.

Simultaneously with the circulation of this first fluid A, the second fluid B enters through the inlet pipe 16 into the sealed chamber 1 at a temperature of the order of 200 ° C. This second fluid B after having filled the annular space 5, enters through the open ends 28b of the rear walls 23 of each of the plate bundles 20 and passes through each of these bundles of plates 20 against the current of the first fluid A. An exchange Thus, in each of the plate bundles 20, the thermal fluid is produced between the fluids A and B and the second fluid B, thus heated, is discharged from the open ends 26b. each of the bundles of plates 20, then is collected by the annular collector 30 before being discharged by the space between the bottom 13 of the central collector 10 and the hemispherical cap 31, and by the tubing 32.

During the passage of the hot fluid A and the cold fluid B in the various elements of the installation, and in particular in the plate bundles 20, the thermal stresses generated cause an expansion of the plates 21 of the bundles of plates 20 and, since each of these bundles of plates is supported inside the sealed enclosure 1 by means of a sliding support provided between these bundles of plates 20 and the support members 25, these bundles of plates can expand freely which allows to avoid significant thermal stresses at each of these bundles of plates 20. It is the same at the inlet pipe 14 of the hot fluid, the pipe 32 output of the cold fluid reheated after its passage in each of the plate bundles 20 as well as at each of the conduits 36 which are equipped with expansion joints, respectively 15, 33 and 37.

The heat exchange system according to the invention has the advantage of making it possible to concentrate the arrival of the hot fluid in the center of the sealed enclosure 1 by means of a central collector 10 and to surround this hot zone by a peripheral cold buffer zone by means of the deflectors respectively 45, 46 and 47 around the inlet pipe 14 of the hot fluid, the central collector 10 and the pipe 32 for discharging the heated fluid.

These buffer zones thus formed around the hot zones make it possible to make a sealed enclosure 1 having a relatively small thickness compared to the sealed enclosures of the heat exchange installations used until now.

The heat exchange system according to the invention has the advantage, because of its design, of being compact and of having a large exchange surface, while allowing the various elements of the component to be able to expand freely from the makes a significant temperature difference between the hot fluid and the cold fluid.

Claims (13)

1. Installation for heat exchange between fluids, of the type comprising a vertical, elongated sealed enclosure (1), means (20) for heat exchange between the fluids, and intake means (14, 16) and evacuation means (32, 41) for a first fluid A and second fluid B, characterised in that the heat exchange means comprise plate bundles (20) formed by a stack of horizontal plates (21) defining between them two circulation circuits for the two fluids A and B in counter-current and distributed in a star-shape around a tubular central collector (10) concentric with the enclosure (1) and in that each plate bundle (20) comprises a vertical front wall (22) fixed to the central collector (10) and provided with inlets (26a) and outlets (26b) for each of the fluids A and B and a free vertical back wall (23) provided with inlets (28b) and outlets (28a) for each of these fluids A and B, each plate bundle (20) being in sliding contact with a support member (25) fixedly connected to the sealed enclosure (1).
2. Installation according to claim 1, characterised in that the fluid inlets and outlets provided on the front wall (22) are formed, for each circuit, by an alternating superimposed arrangement of open ends (26a, 26b) or closed ends (27a, 27b), the open ends (26a) of the inlets to the circuit for the first fluid A being located in the centre of the front wall (22) and the open ends (26b) of the outlets from the circuit for the second fluid B being located on the side edges of this front wall (22).
3. Installation according to claim 2, characterised in that the open ends (26a) of the inlets for the first fluid A open into the central collector (10) connected to the intake means (14) for this first fluid A.
4. Installation according to claim 3, characterised in that the intake means for the first fluid A are formed by at least one tube (14) passing through the enclosure (1) and connected to the upper part of the central collector (10), said tube (14) being provided with at least one expansion compensator (15).
5. Installation according to claim 2, characterised in that the open ends (16b) of the outlets for the second fluid B in the side edges of the front walls (22) of two adjacent plate bundles (20) are connected to one another by an annular collector (30) concentric with said central collector (10) and comprising, at the lower end, a hemispherical cup (31) connected to the evacuation means (32) for this second fluid B.
6. Installation according to claim 5, characterised in that the evacuation means (32) for the second fluid B are formed by at least one tube (32) passing through the sealed enclosure (1) at its lower end, said tube (32) being provided with at least one expansion compensator (33).
7. Installation according to claim 1, characterised in that the inlets and outlets for the fluids A and B provided on the back wall (23) are formed, for each circuit, by an alternating superimposed arrangement of open ends (28a, 28b) or closed ends (29a, 29b), the open ends (28b) of the inlets to the circuit for the second fluid B being located in the centre of the back wall (23) and the open ends (28a) of the outlets for the second fluid A being located on the side edges of each back wall (23).
8. Installation according to claim 1, characterised in that the inlets and outlets for the fluids provided on the back wall (23) are formed, for each circuit, by an alternating superimposed arrangement of open ends (28a, 28b) or closed ends (29a, 29b), the open ends (28b) of the inlets to the circuit for the second fluid B being located on the side edges of the back wall (23) and the open ends (28a) of the outlets for the first fluid A being located in the centre of this back wall (23).
9. Installation according to claim 7 or 8, characterised in that the open ends (28b) of the inlets for the second fluid B open into the annular space (5) between the central collector (10) and the enclosure (1), said annular space (5) being connected to the intake means (16) for this second fluid B.
10. Installation according to claim 9, characterised in that the intake means for the second fluid B are formed by at least one tube (16) passing through the enclosure (1) and opening into the interior of said enclosure (1).
11. Installation according to claim 7 or 8, characterised in that the open ends (28a) of the outlets for the first fluid A are surmounted by a collector (35) connected by at least one duct (36) provided with at least one expansion compensator (37) to a collecting ring (40) connected to the evacuation means (41) for the first fluid A.
12. Installation according to any one of the preceding claims, characterised in that each plate bundle (20) comprises, on each of its side walls (24), a vertical deflector (45) extending in the direction of the adjacent plate bundle (20), the free edges (45a) of two contiguous deflectors (45) overlapping one another.
13. Installation according to any one of the preceding claims, characterised in that the first fluid A is a hot fluid at a temperature of the order of 800°C as it enters the plate bundles (20) and the second fluid B is a cold fluid at a temperature of the order of 200°C as it enters said plate bundles (20).

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