EP0644394A1 - Heat-exchanger - Google Patents

Abstract

The heat exchanger includes a jacket (casing, housing) (1) having a bundle of heat exchange tubes (pipes) (2) and having stubs (sockets, connectors) (10, 11) which serve to guide an intertubular medium in and out and between which a longitudinal partition (9) is located. A receiving chamber (4) connected to one of the end faces of the jacket (1) is provided with stubs (sockets, connecting pieces) (6, 7) for guiding a heat carrier in and out. A means (14) for hermetically tight connection of the longitudinal partition and the jacket (1) is designed in the form of packets (15) of elastic strips (16) which are connected to both sides of the longitudinal partion (9) over their entire length in a symmetric fashion in sections adjoining the inside surface of the jacket (1). A part of each strip (16) projects over the boundaries of the partition (9) and makes contact with the inside surface of the jacket (1). <IMAGE>

Description

Technical field

The invention relates to heat exchange apparatuses in which the heat carriers do not come into direct contact with one another, in particular it relates to a heat exchanger.

The present invention can be most effectively applied to the petroleum, petrochemical, chemical, petroleum, gas, energy, and other industries.

Underlying state of the art

-förmigen Warmeaustauschrohren verbunden.A heat exchanger is known (Spravochnik po teploobmennikam (Handbook for heat exchangers) vol. 1, 1987, p. 38), which includes a jacket in which a bundle of tubes with transverse partition walls is attached to tube sheets, which are spaced apart from one another over the length of the jacket . A collecting chamber is connected to one of the end faces of the jacket and is divided into an entry and an exit section by a longitudinal partition. The jacket is provided with sockets for the introduction and removal of heat transfer media. On the other face of the jacket, the tube bundle is either with a floating head or with

-shaped heat exchange tubes connected.

A major disadvantage of this heat exchanger is that its counterflow index is 0.5 (the largest possible value is 1), which is why it is related to the tube bundle is two-course and in relation to the pipe gap.

Another heat exchanger (SU, A, 1451518) is known, which contains a jacket with a bundle of heat exchange tubes fastened in tube sheets and with connecting pieces for inserting and removing a heat transfer medium, between which there is a longitudinal partition. A series of transverse partition walls is arranged in the space between the tubes. A collection chamber is connected to one of the end faces of the jacket and is divided into an inlet and an outlet section by a longitudinal partition wall and is provided with corresponding connections for the introduction and removal of another heat transfer medium. The heat exchanger contains a means for hermetically sealing the partition wall to the casing, which is in the form of lock connections. Each lock connection comprises a tubular socket, which on the one hand is rigidly connected to the inner surface of the casing, but on the other hand has a longitudinal slot, and a reinforcement on the lateral section of the longitudinal partition wall adjoining the casing, which reinforcement is accommodated in the socket.

The frame of each lock connection is made of a thermoelastic material. At the end of the casing remote from the collecting chamber, a device for ejecting the longitudinal partition wall from the sockets when the heat exchanger is disassembled is mounted in front of the sockets. At the other end of the jacket, the tube bundle is connected to a floating head, which includes a tube sheet with a lid.

When working with this heat exchanger, two paths of the heat transfer flows occur in the tube space and in the tube space. The design of two flow paths in the space between the tubes allows the counterflow index to be increased from 0.5 to 1.0, the heat transfer effectiveness of the heat exchanger increasing on average by 12 to 22%.

A major disadvantage of the design of the heat exchanger is the need to provide corresponding recesses in the tube sheet distant from the collecting chamber, in order to allow it to pass the sockets and the ejection device when the heat exchanger is disassembled. This complicates the design of the heat exchanger and reduces the tightness of the tube sheet with the cover of the floating head.

Another disadvantage of the design of the heat exchanger is that it is impossible to ensure a strict straightness of the mounting of the sockets on the inner surface of the jacket, which creates considerable difficulties in the assembly and disassembly of the tube bundle.

In addition, the dismantling of the tube bundle is made more difficult by coking the space inside the sockets.

The use of the cross partitions increases the Path length of the current in the space between the tubes, however, leads to an almost double increase in the hydraulic resistance. In addition, there are standstill zones in the vicinity of the transverse partition walls, in which the deposition of coke and tars on the outer surface of the pipes increases, which reduces the heat exchange.

Another disadvantage of the design of the heat exchanger is the fact that due to the arrangement of the longitudinal partition wall in the tube bundle and the increase in the counterflow index to one, mechanical stresses in the rolled connections of the tube sheets increase due to different thermal expansion of the tubes in the bundle. This reduces the reliability of the design of the heat exchanger.

And finally, the disadvantage of the design of the heat exchanger is the creation of "parasitic" heat flows through the longitudinal partition due to a temperature gradient of the heat transfer medium on different sides of the longitudinal partition. The presence of "parasitic" heat flows reduces the heat effectiveness of the heat exchanger.

Disclosure of the invention

The present invention has for its object to provide a heat exchanger in which the means for hermetically sealing the partition to the jacket would have a construction which would allow the construction of the heat exchanger as a whole to ensure reliable hermeticization in the connection zone of the Simplify the longitudinal partition and the jacket.

The object is achieved in that in the heat exchanger, containing a jacket with a bundle of heat exchange tubes and with sockets for introducing and removing a heat transfer medium, between which there is a longitudinal partition, a collecting chamber which is connected to one of the end faces of the jacket and with sockets for Inserting and removing another heat transfer medium is provided, and a means for hermetically sealing the partition wall to the jacket, according to the invention the means for hermetically sealing the partition wall to the jacket is in the form of packages of elastic bands, which is at least on one of the sides the longitudinal dividing wall are fixed symmetrically over their length in the sections adjacent to the inner surface of the casing, a part of each band projecting beyond the boundaries of the dividing wall and making contact with the inner surface of the casing.

The proposed construction of the means for hermetically sealing the partition and the jacket offers the possibility of creating a "labyrinth seal" in the connecting zone of the partition and the jacket, which increases the reliability of the hermeticization in this zone and simplifies the construction of the heat exchanger as a whole .

Such a construction of the agent eliminates the need to make cutouts in the tube sheet and simplifies the assembly and disassembly of the heat exchanger.

In a preferred embodiment of the invention, a number of transverse partition walls are arranged in the jacket, which are spaced apart from one another over the length of the tubes and each of which consists of bars which are located between the tubes and are fastened in a half ring attached to the longitudinal partition.

This design variant contributes to increasing the turbulence of the flow, which is necessary to intensify the heat exchanger. In addition, the presence of the half rings reduces the gap between the tube bundle and the jacket, which leads to a reduction in the heat losses due to a transition into the environment via the jacket. The use of the transversal bottoms makes it possible to rule out the occurrence of standstill zones in the heat exchanger and makes it easier for the latter to be cleared of deposits.

In another embodiment of the invention, a support partition is arranged in the tube bundle, which is located outside the boundaries of the longitudinal partition at the end of the jacket remote from the collecting chamber.

Such an embodiment variant of the invention makes it possible to increase the rigidity of the tube bundle and, as a result, to increase the operational reliability of the heat exchanger.

According to one embodiment of the invention, the strips in each package have a different width, which increases in the direction from the longitudinal partition wall to the tubes.

It is quite expedient for at least a part of the partition wall which adjoins the collecting chamber to have a thermal insulation coating.

Such an embodiment variant of the invention makes it possible to practically exclude the formation of "parasitic" heat flows through the longitudinal partition wall, which in turn can increase the heat effectiveness of the heat exchanger.

In a further embodiment variant of the invention, the strips in each package are made from bimetal.

According to one of the embodiment variants of the invention, guides for tape packs are provided, each of which is arranged at the end of the longitudinal partition wall remote from the collecting chamber between the latter and one of the tape packs.

This embodiment of the invention makes it considerably easier to assemble the heat exchanger.

It is expedient that at least some of the tubes have a cord.

Such a design of the pipes makes them more plastic. Such pipes have a higher reliability than the conventional ones because they reduce mechanical stresses in the rolled connections of the tube sheet and the tubes.

Brief description of the drawings

• Fig. 1 das Prinzipschema des erfindungsgemässen Wärmeaustauschers;
• Fig. 2 einen Schnitt nach Linie II - II der Fig. 1 (im vergrösserten Massstab);
• Fig. 3 die Baugruppe der Befestigung des Bänderpaketes an der Längstrennwand im Ausgangszustand (vor dem Zusammenbau des Wärmeaustauschers);
• Fig. 4 einen Schnitt nach Linie IV - IV der Fig. 1;
• Fig. 5 einen Teil des Rohres mit Kordierung.

Other objects and advantages of the present invention will become apparent from the following detailed description of the embodiments thereof, and from the accompanying drawings, in which:

• 1 shows the basic diagram of the heat exchanger according to the invention;
• FIG. 2 shows a section along line II-II of FIG. 1 (on an enlarged scale);
• Figure 3 shows the assembly of the fastening of the ribbon package on the longitudinal partition in the initial state (before the assembly of the heat exchanger).
• Fig. 4 is a section along line IV - IV of Fig. 1;
• Fig. 5 shows a part of the tube with cord.

Best embodiment of the invention

The heat exchanger contains a jacket 1 (Fig. 1), in the interior of which there is a bundle of heat exchange tubes 2, which are fastened in tube sheets 3, 31. On one end face, the jacket 1 is provided with a collecting chamber 4 with a longitudinal partition 5, which is located between connecting pieces 6, 7 for the introduction and removal of a heat transfer medium. On the other end of the jacket 1, the bundle of tubes 2 is equipped with a floating head 8 with a cover (not shown).

In the jacket 1, a longitudinal partition 9 is arranged in the bundle of tubes 2, which is attached to the tube sheet 3, which is located between the collecting chamber 4 and the jacket 1. The partition 9 is arranged between the connecting pieces 10, 11 for the insertion and removal of another heat transfer medium.

At least a part of the partition 9, which adjoins the collecting chamber 4, has thermal insulation in the form of intermediate layers 12 made of heat-insulating material (e.g. fiberglass, paranite, paralon), which are arranged on both sides of the partition. It is preferred that the length of the intermediate layers 12 (FIG. 3) is at least 67% of the length of the partition 9.

worin bedeuten:
E - Effektivität der Wärmeübertragung (in diesem Fall des nicht isolierten Teils der Längstrennwand);
$$\text{U =}\frac{\text{KF}}{\text{W }}$$

- relative Wärmeleistung;
K - Wärmeübergangszahl, in erster Annäherung als konstant angenommen;
W - Wasseräquivalent des Wärmeflusses;
F - Wärmeaustauschfläche (in diesem Fall wird sie bei der konstanten Breite der Längstrennwand zur Länge des nicht isolierten Teils derselben proportional sein: $\text{F = AX}$

).A reason for the permissible length of the non-insulated part of the longitudinal partition wall can be obtained from logical and mathematical considerations. The dependence of the effectiveness of the countercurrent heat transfer process (VMKei, AL London "Kompaktnye teploobmenniki" / Kompakt heat exchanger, 1967, Verlag Energia / Moscow /, p. 25) on the size of the surface is expressed by the following formula:

in which mean:
E - effectiveness of heat transfer (in this case the non-insulated part of the longitudinal partition);
$$\text{U =}\frac{\text{KF}}{\text{W}}$$

- relative heat output;
K - heat transfer coefficient, in the first approximation assumed to be constant;
W - water equivalent of heat flow;
F - heat exchange surface (in this case, given the constant width of the longitudinal partition, it will be proportional to the length of the non-insulated part thereof: $\text{F = AX}$

).

bestimmt, wo Δt die Temperaturdifferenz auf verschiedenen Seiten der Längsplatte (Längstrennwand) ist. Sie lässt sich in erster Annäherung durch die lineare Abhängigkeit von der Länge des nicht isolierten Teils ausdrücken:

$\text{Δt = B (I - X).}$

The amount of heat of the "parasitic" heat flow is calculated according to the formula

$\text{ΔQ = E · Δt · n}$

determines where Δt is the temperature difference on different sides of the longitudinal plate (longitudinal partition). It can be expressed as a first approximation by the linear dependence on the length of the non-isolated part:

$\text{Δt = B (I - X).}$

Obwohl diese Fraktion monoton ist, hat sie eine Wendung.Under the assumed conditions, the amount of "parasitic" heat flow can be written as

Although this faction is monotonous, it has a twist.

In order to determine the turn of the function, ie at which size of the non-insulated part of the longitudinal partition the "parasitic" heat flow will still be insignificant, it is necessary to take the second derivative of the function and to set its value to zero.

The calculation of X under this condition under real operating conditions of the heat exchanger φ = 5- 5.5 (BMKeis, AL London. "Kompaktnye teploobmenniki", p. 44, Fig. 2-12 ÷ 2-21) gives a value X, ie the size of the non-insulated part of the longitudinal divider, equal to 0.25 - 0.37.

In general, in similar, a priori unclear cases, the optimal solution, as indicated by information theory, is a ratio that corresponds to the "golden ratio", i.e. 37.0 and 63.0%, of which the inventors are guided, but as a reserve variant, they suggest isolating the longitudinal plate over 25% of its length, but preferably 63%.

The intermediate layers 12 are protected by sheets 13.

The heat exchanger is provided with a means 14 for hermetically sealing the partition 9 and the casing 1, which is in the form of packages 15 (Fig. 2-4) elastic bands 16, which at least on one of the sides of the partition 9 above it Length in sections adjacent to the inner surface of the jacket 1 are attached symmetrically. A part of each band 16 protrudes beyond the boundaries of the partition 9 and contacts the inner surface of the jacket 1, whereby a labyrinth seal (Fig. 2, 4) is formed. I _n each packet 15 have the strips 16 have a different width in the direction of the partition wall 9 to the tubes 2 (Fig. 3) increases toward. The packages 15 are fastened to the partition 9 by means of bolts 17 with inserts 18.

The straps 16 in each package 15 can be made with shape memory or bimetal.

The packets 15 of the belts 16 are equipped with guides 19 (FIG. 4) which are arranged on the end of the partition 9 closest to the floating head 8. Each guide 19 is located between the respective package 15 of the belts 16 and the partition 9.

In the bundle of tubes 2 there is a row of transverse partition walls 20 (FIGS. 1, 2) which are spaced apart from one another over the length of the tubes 2 and each of which consists of rods 21 which are located between the tubes 2 and in one the partition 9 attached half ring 22 are attached.

In the vicinity of the floating head 8, a support partition 23 is arranged in the bundle of tubes 2 and is located outside the boundaries of the partition 9.

Each tube 2 has a cord 24 (Fig. 5).

The heat exchanger is installed as follows. First, a series of transverse partition walls 20 is welded to the partition 9, from which one of the ends of the partition 9 is welded to one of the tube sheets 3. Then you insert the tubes 2 into the transverse partitions 20 and roll the ends of the tubes 2 and weld them to the tube sheets 3, 31. The tube sheet 3 and the partitions 20 are encompassed by guide strips (not shown) which form the framework of the tube bundle.

On the flanks of the partition 9, the packs 15 of the strips 16 are attached with the aid of the screw bolts 17, the ends of which are bent with the help of the guides 19 which are arranged at one of the ends of the partition 9.

The bundle prepared in this way is inserted into the jacket 1. The bundle of tubes 2 is hermetically sealed on one end by the cover of the floating head 8, while on the other end the jacket 1 is hermetically sealed to the collecting chamber 4.

Before starting work, the connections 6, 7, 10, 11 are connected by means of pipes (not shown) for supplying and removing the heat transfer medium.

The heat exchanger according to the invention works as follows.

The heat transfer streams enter the heat exchanger in counterflow. One of the streams passes through the nozzle 6 of the collecting chamber 4 into the tubes 2 and then into the floating head 8, after which it reaches the chamber 4 again via the heat exchange tubes 2 and leaves the heat exchanger through the nozzle 7.

The other stream enters the nozzle 10 and reaches the pipe gap by running around the heat-insulated longitudinal partition 9, the stream being swirled by the partition walls 20 and, after accepting the heat from the first stream, from the jacket 1 through the Port 11 emerges.

Commercial usability

The invention can be used in the petroleum, petrochemical, chemical, petroleum, gas, and other industries.

Claims (9)

Heat exchanger, comprising a jacket (1) with a bundle of heat exchange tubes (2) and with sockets (10, 11) for inserting and removing a heat transfer medium, between which there is a longitudinal partition wall (9), a collecting chamber (4), with one of the end faces of the jacket (1) is connected and provided with sockets (6, 7) for the introduction and removal of another heat transfer medium, and a means (14) for hermetically sealing the partition (9) to the jacket (1), characterized in that the means (14) for the hermetically sealed connection of the partition (9) to the casing (1) is in the form of packages (15) of elastic bands (16) which are arranged on at least one side of the longitudinal partition (9) along their length in the sections adjoining the inner surface of the jacket (1) are attached symmetrically, part of each band (16) protruding beyond the boundaries of the partition (9) and making contact with the inner surface of the jacket (1). Heat exchanger according to claim 1, characterized in that a series of transverse partition walls (20) is arranged in the jacket (1), which are spaced apart from one another over the length of the tubes (2) and each of which consists of rods (21) which are between the tubes (2) and are attached in a half ring (22) attached to the partition (9). Heat exchanger according to Claim 1, characterized in that a support partition (23) is arranged in the bundle of tubes (2) and is located outside the limits of the longitudinal partition (9) at the end of the jacket (4) remote from the collecting chamber (4) . Heat exchanger according to claim 1, characterized in that the bands (16) in each package (15) have a different width, which increases in the direction of the longitudinal partition (9) towards the tubes (2). Heat exchanger according to claim 1, characterized in that at least a part of the partition wall (9) which adjoins the collecting chamber (4) has a heat insulation coating (12). Heat exchanger according to claims 1, 4, characterized in that the belts (16) in each package (15) are made of a material with shape memory. Heat exchanger according to claims 1, 4, 6, characterized in that the strips (16) in each package (15) consist of bimetal. Heat exchanger according to claims 1, 4, 6, 7, characterized in that it is equipped with guides (19) for the packages (15) of the belts (16), each of which at the end of the longitudinal partition wall remote from the collecting chamber (14) (9) between the latter and one of the packages (15) of the belts (16) is arranged. Heat exchanger according to claims 1, 2, 3, characterized in that at least some of the tubes (12) have a cord (25).

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