WO2017167458A1

WO2017167458A1 - Wound heat exchanger

Info

Publication number: WO2017167458A1
Application number: PCT/EP2017/025070
Authority: WO
Inventors: Manfred Steinbauer; Christiane Kerber; Jürgen Spreemann; Ingomar Blum; Konrad Braun; Martin Stadler
Original assignee: Linde Aktiengesellschaft
Priority date: 2016-03-30
Filing date: 2017-03-29
Publication date: 2017-10-05

Abstract

The invention relates to a heat exchanger (1), comprising: a pre-distributor (100) for receiving a liquid phase (F) to be distributed onto a tube bundle (2) of the heat exchanger (1), a core tube (3), which extends along a longitudinal axis (Z) and on which a plurality of tubes (20) is wound, which form the tube bundle (2), a main distributor (200), which has a plurality of distributor arms (201) protruding from the core tube (3) for distributing said liquid phase (F) onto the tube bundle (2), wherein the distributor arms (201) are fluidically connected to the pre-distributor (100) by means of a flow path (30) extending in the core tube (3) such that the liquid phase (F) can be fed from the pre-distributor (100) into the distributor arms (201) of the main distributor (200) via the flow path (30). According to the invention, one, a plurality, or all of the distributor arms (201) are fluidically connected to the pre-distributor (100) by means of at least one respective down-tube (10), which extends along the longitudinal axis and outside of the core tube (3), such that the liquid phase (F) to be distributed can be fed from the pre-distributor (100) into the distributor arm (201) in question also via the associated down-tube (10).

Description

description

Coiled heat exchanger

The invention relates to a heat exchanger according to claim 1.

Such a heat exchanger is used for indirect heat exchange between at least a first medium, which is guided in a tube bundle of the heat exchanger and a second medium which is guided in a surrounding the tube bundle shell space, by a pressure-bearing jacket of the

Heat exchanger is limited.

In such heat exchangers, e.g. in LNG systems, the two-phase entering refrigerant is usually separated in a pre-manifold of the heat exchanger by gravity in a gaseous phase and a liquid phase and then passed the liquid phase in a main manifold and abandoned by this (as a second medium) on the tube bundle ,

Here, e.g. the liquid phase from the pre-distributor passed through a central core tube of the heat exchanger in the main distributor.

However, gas is entrained during the precipitation of the liquid phase from the predistributor into the central core tube, and for constructional reasons it is often not possible to dimension the diameter of the core tube so large that the backflowing gas can escape upwards past the newly flowing liquid phase ,

The gaseous phase hindered in this way, in turn, hampers the newly flowing in liquid phase, resulting in a two-phase flow which ensures a proper inflow of the liquid phase into the liquid phase

Obstructed distribution arms of the main distributor and thus disturbs in the distributor arms the uniform distribution of the liquid phase on the tube bundle. These effects significantly reduce the performance of the heat exchanger. This is a serious problem, in particular in the case of existing plants for which an increase in capacity is to be carried out, since here no subsequent enlargement of the core tube diameter is possible on a regular basis. Proceeding from this, the present invention is therefore based on the object of providing a heat exchanger and a corresponding method for distributing a liquid phase, which reduces the problems mentioned above. This object is achieved by a heat exchanger with the features of claim 1. Advantageous embodiments of the invention are specified in the corresponding subclaims.

According to claim 1, a heat exchanger is provided, comprising:

a pre-distributor for receiving a liquid phase to be distributed to a tube bundle of the heat exchanger,

a core tube extended along a longitudinal axis, on which a plurality of tubes is wound, which form the tube bundle,

- A main distributor, a plurality of projecting from the core tube

Distributor arms for distributing that liquid to the tube bundle, wherein the distributor arms are in fluid communication with the pre-distributor via a flow path in the core tube, so that the liquid phase from the predistributor can be fed via the flow path into distributor arms of the main distributor,

- Is provided according to the invention that at least one of the distributor arms over at least one along the longitudinal axis extending downpipe, which runs outside the core tube, is in flow communication with the pre-manifold, so that the liquid phase to be distributed also via said at least one downpipe from the predistributor in the at least one distributor arm can be fed.

According to one embodiment, it may further be provided that a plurality or all of the distributor arms are in fluid communication with the predistributor via at least one downpipe extending along the longitudinal axis, so that the distributing liquid phase can also be fed via the respective downpipe from the distributor in the respective distributor arm.

By installing additional downpipes, which are also referred to as downcomers, the free cross section for draining the liquid phase can advantageously be increased in such a way that degassing of the liquid phase is possible.

Furthermore, by means of the invention, an oversupply of the inner layers of the tube bundle during startup of the system can be avoided since the liquid phase can be radially distributed further outward through the additional downpipes. As a result, typical thermo-hydraulic problems during startup of the system can be avoided, which reduces the amount of gas usually burned off during startup in LNG plants. According to one embodiment of the heat exchanger according to the invention it is provided that the heat exchanger has a jacket extending along the longitudinal axis, which extends coaxially to the core tube, wherein the jacket a

Enclosing space surrounds, in which the pre-distributor, the main distributor, the tube bundle and the core tube and the at least one drop tube are arranged. The jacket space further serves to receive the liquid phase (second medium) to be distributed to the tube bundle.

Furthermore, according to a preferred embodiment of the heat exchanger according to the invention, it is provided that the at least one downpipe or the downpipes extend in the radial direction of the jacket in each case further outward than the core tube in the jacket space along the longitudinal axis. The downpipes are therefore arranged in particular around the core tube and run largely or in sections parallel to the core tube or parallel to the longitudinal axis of the jacket. Furthermore, it is provided according to a preferred embodiment of the heat exchanger according to the invention, that the at least one downpipe or the downpipes each open from above into a roof of the associated distribution arm, wherein the respective roof limits the respective distributor arm upwards. Furthermore, it is provided according to a preferred embodiment of the heat exchanger according to the invention, that the respective distributor arm starting from the core tube in the radial direction of the jacket outwardly to a the

Main distributor extends facing inside of the shell.

Furthermore, according to one embodiment of the invention

Heat exchanger provided that between each two adjacent distributor arms, there is a gap through which, for example, tubes of the tube bundle are guided along the longitudinal axis of the shell upwards and then open above the main distributor or above the distribution arms of the main distributor in the jacket provided on the neck.

Furthermore, according to a preferred embodiment of the heat exchanger according to the invention, it is provided that the respective distributor arm has a bottom extending perpendicular to the longitudinal axis with a plurality of outlet openings, via which the liquid phase can be applied to the tube bundle arranged below the respective distributor arm.

The respective distributor arm preferably has two lateral walls which extend in the radial direction of the jacket and which each extend upwards from the bottom of the respective distributor arm in the direction of the longitudinal axis of the jacket, the lateral walls of the respective distributor arm pointing in the radial direction of the jacket towards the inside of the jacket diverge, so that the respective distributor arm has a circular sector-shaped or pie-shaped cross-section substantially perpendicular to the longitudinal axis.

Furthermore, the respective distributor arm preferably has an end wall connecting the two lateral walls of the respective distributor arm and extending upwards along the longitudinal axis from the bottom of the respective distributor arm, the front wall of the respective distributor arm facing the inside of the jacket in the radial direction of the jacket ,

The said roof of the respective distributor arm preferably adjoins the said lateral side walls and the front wall of the respective distributor arm at the top. It is preferably provided that the roof of the respective Verteilerarms in the radial direction of the shell towards the outside, ie towards the inside of the shell down, falls off.

Furthermore, according to one embodiment of the present invention, provision is made for a distributor arm, a plurality of distributor arms or all distributor arms to be in fluid communication with the predistributor via a plurality of downcomers along the longitudinal axis, so that the liquid phase to be distributed in addition to the flow path in the core tube respective downpipes from the pre-distributor in the respective distributor arm can be fed.

In particular, in the event that several downpipes are used per distribution arm, they can be configured in terms of their inner diameter so that a submerged operation of the downpipes is possible. In this case, the level of the liquid phase in the pre-distributor is above the inlet openings of the downpipes provided in or at the bottom of the pre-distributor, so that the liquid phase in the

Essentially without Gasmittriss in the downpipes down to the distribution arms of the main manifold is conductive.

Due to the fact that the additional downpipes radially seen further out into the main distribution arms, is an oversupply of the inner layers of the

Tube bundle eliminated with the associated problems during startup.

Furthermore, according to one embodiment of the invention

Heat exchanger provided that the pre-distributor has a perpendicular to the longitudinal axis bottom, wherein the bottom has a central opening through which the bottom in flow communication with the surrounding of the core tube

Flow path is. Said central opening in the bottom of the pre-distributor is preferably arranged below a baffle plate provided in the pre-distributor. Furthermore, according to one embodiment of the invention

Heat exchanger provided that the pre-distributor is in fluid communication with the respective downpipe via a respective provided in or at the bottom inlet opening of the respective downpipe, wherein the inlet openings are arranged around the central opening. Furthermore, one or more weirs may be provided on the floor of the predistributor or protrude upwards from the floor in the direction of the longitudinal axis, wherein the liquid phase defined on the floor can be stowed by means of the weirs. As a result, the individual downpipes can be charged, for example, depending on the level of the liquid phase in the pre-distributor with the liquid phase. Thus, the supply of the main distributor for starting the heat exchanger can be optimally adjusted optimally, for example, by different weir heights at the side downpipes and central inlet to the core tube or flow path. Furthermore, according to one embodiment of the invention

Heat exchanger provided that the heat exchanger has a supply line which is in flow connection with the pre-distributor, having an outlet opening which is arranged along the longitudinal axis above the baffle plate (eg in the form of a baffle plate) of the pre-distributor and this particular faces, so that one of Outlet opening of the supply line flowing two-phase mixture hits the baffle plate and flows from this to the bottom of the pre-distributor.

Furthermore, according to one embodiment of the invention

Heat exchanger provided that the core tube of the heat exchanger is configured to receive the load of the tubes of the tube bundle. These are preferably helically wound in several layers on the core tube for this purpose. Between the individual pipe layers, spacer webs are preferably provided, which are e.g. can run along the longitudinal axis. For introducing and discharging media, the tubes can be grouped together, which open into provided on the jacket nozzle.

According to another aspect of the present invention, a method for distributing a liquid phase to a tube bundle of a heat exchanger according to claim 13 is disclosed. Thereafter, a method for distributing a liquid phase to a tube bundle of a wound heat exchanger is proposed, which uses in particular a heat exchanger according to the invention or herein described, wherein a two-phase mixture having a liquid phase and a gaseous phase is placed in a pre-distributor, so that the two-phase mixture is calmed and outgas at least a portion of the gaseous phase of the two-phase mixture can, wherein the liquid phase is passed via a flow path guided in a core tube of the heat exchanger in a plurality of distributor arms of a main distributor of the heat exchanger and from there to a tube bundle having a plurality of tubes wound on the core tube, and wherein the liquid Phase from the pre-distributor in addition to at least one along a

Longitudinally extending downpipe is directed into a distribution arm of the main distributor, wherein the downpipe extends outside of the core tube.

According to one embodiment, it can further be provided that several or all distributor arms each extend over at least one along the longitudinal axis

Drop pipe are in flow communication with the pre-distributor, wherein the liquid phase to be distributed is also fed via the respective downpipe from the pre-distributor into the respective distributor arm. According to one embodiment of the method according to the invention, it is provided that the pre-distributor with a distributor arm, a plurality of distributor arms or all distributor arms of the main distributor via a plurality of downcomers in

Flow connection is, wherein the liquid phase from the pre-distributor is additionally passed through the respective plurality of downcomers in the respective distribution arm.

Furthermore, it is preferably provided that the downpipes are arranged in the radial direction of the jacket further out than the central core tube. The downpipes are thus grouped around the core tube and extend along the

Longitudinal axis of the jacket.

A further embodiment of the method according to the invention provides that the liquid phase is dammed up defined on the ground, so that the individual

Downpipes e.g. be charged depending on the level of the liquid phase in the pre-distributor with the liquid phase. Thus, the supply of the main distributor with liquid phase for the startup of the heat exchanger can be targeted optimally adjusted (see also above).

Furthermore, according to one embodiment, it is provided that the downpipes

(especially when multiple downpipes are used per distribution arm) operated submerged. Ie the inlet openings are to the downpipes below the level of the liquid phase in the pre-distributor, so that the Gasmittriss is reduced in the main distributor.

As a result, the invention advantageously makes it possible to increase the free cross section for running off the liquid phase, so that degassing of the liquid is possible. In particular, a submerged operation of the downpipes is possible, with the additional advantage of conducting liquid phase without Gasmitriss down. Due to the fact that the additional downspouts are seen radially in the outside

Hauptverteilerarme occur, an oversupply of the inner layers is eliminated with the associated problems during startup. By different

Weir heights with side downpipes and central inlet, the supply of the main distributor for the start can be optimally set optimally.

Further details and advantages of the invention will become apparent from the following

Figure description of an embodiment illustrated by the figures.

Show it:

Fig. 1 is a schematic, sectional view of an inventive

heat exchanger; and

Fig. 2 is a schematic plan view of the bottoms of the distributor arms of

Main distributor of the heat exchanger shown in FIG. FIG. 1 shows, in connection with FIG. 2, a wound heat exchanger 1 with a tube bundle 2 which serves to receive a first medium S which is to undergo indirect heat exchange with a liquid phase F driven in a jacket space 5 surrounding the tube bundle 2. The shell space 5 is bounded by a pressure-bearing jacket 4, which extends along a longitudinal or

Cylinder axis Z extends, which is aligned parallel to the vertical.

The tube bundle 2 has a plurality of tubes 20, each of which is helically wound on a core tube 3 which is elongated along the longitudinal axis Z and which is arranged coaxially with the jacket 4 in the jacket space 5. For distributing the liquid phase F on the tube bundle 2 is first a

Two-phase mixture S 'over a e.g. along the longitudinal axis Z extending supply line 104 from above into a pre-distributor 100 of the heat exchanger 1 passed. The predistributor 100 has a bottom 101 extending transversely to the longitudinal axis Z and a circumferential lateral wall 102 which extends therefrom. The supply line 104 further has a downward-pointing outlet opening 105, which is opposite to a baffle plate 103, which is arranged above the bottom 101 of the pre-distributor 100 in the pre-distributor 100. The two-phase mixture S 'can flow from the baffle plate 103 to the bottom 101 and is collected and calmed there, whereby a gaseous phase G can outgas from the two-phase mixture S'.

The bottom 101 of the pre-distributor 100 further has a central opening 106, through which the liquid phase F can flow into the core tube 3, which is in flow communication with the opening 106. The liquid phase F can be guided in a tube arranged in the core tube 3 or in the core tube 3 itself. In other words, therefore, a flow path 30 is present in the core tube 3, via which the liquid phase F from the pre-distributor 100 in below the bottom 101 of Pre-distributor 100 provided distributor arms 201 can be guided, which in each case in a radial direction R depart from the core tube 3 and thereby extend to an inner side 4a of the shell 4. The distributor arms 201 form a main distributor 200 of the

Heat exchanger 1, the task of which is to distribute the liquid phase F from above onto the tube bundle 2.

For this purpose, the distributor arms 201 according to FIG. 2 each have a bottom 202 extending transversely to the longitudinal axis Z, in which a multiplicity of outlet openings 207 are provided, through which the liquid phase F can flow down from above onto the tube bundle 2, which extends along the longitudinal axis Z below the distributor arms 201 is arranged. The distributor arms 201 further each have two lateral, each other

opposite walls 204, 205 which diverge toward the inside 4a of the jacket 4 and respectively connected to each other via a front-side wall 206 which is opposite to the inside 4a of the shell 4, respectively. The distributor arms 201 therefore each have, in particular, a cake piece-like shape. The lateral walls 204, 205 and the frontal wall 206 of the respective Verteilerarmes 201 go further from the bottom 202 of the respective distribution arm 201 along the longitudinal axis Z upwards and each connect to a roof 203 of the respective distribution arm 201, which decreases from the core tube 3, starting to the inside 4a of the shell 4, so that the in the distributor arms 201 entrained gaseous phase G can rise along the roofs 203 to the core tube 3 out.

Between each two adjacent distributor arms 201, a gap 6 is preferably still present, through which tubes 20 of the tube bundle 2 to the

Distributor arms 201 passing along the longitudinal axis Z can be guided upwards.

To the free cross section for draining the liquid phase F in the main manifold 200 and for unhindered rise of the gaseous phase G from the

Main distributor 200 to increase upward is provided according to the invention that preferably each, but at least one or more of the distributor arms 201 via at least one along the longitudinal axis Z extending downpipe 10 with the pre-distributor 100 is in flow communication or is, so that the liquid to be distributed Phase F can also get over the respective downpipe 10 from the pre-distributor 100 in the respective distributor arm 201.

It is provided that the downpipes 10 extend outside of the core tube 3 and have a distance to this in the radial direction R, ie, are arranged further outward than the core tube 3. As shown in Figure 1 by solid lines, each distribution arm 201 According to one embodiment of the invention, be connected via a downpipe 10 with the pre-distributor 201 exactly. Instead of a downpipe 10 per distributor arm 201 according to a further embodiment of the invention, a plurality of downpipes 10 may be present (shown in the figure 1 by dashed lines), which then possibly have a smaller inner diameter to represent the required free cross-section.

The downpipes 10 are in each case flow-connected to the pre-distributor 100 via an inlet opening 11 provided on the bottom 101 of the predistributor 100 and preferably open into the roof 203 from above via an outlet opening 12 of the respectively associated distributor arm 201. The downpipes 10 preferably run parallel to the core tube 3 between the predistributor 100 and the associated distributor arm 201. However, the downpipes 10 may also have an inclination with respect to the longitudinal axis Z or a deviation from a linear or parallel profile.

Furthermore, it may be provided that the inlet openings 1 1 are surrounded by the downpipes 10 of weirs 13, above whose height above the bottom 101, the feed of the liquid phase F to the main manifold 200 can be controlled. This can be particularly advantageous when starting the system (see above).

Due to the downpipes 10 according to the invention, the liquid phase F can now also be supplied to the main distributor 200 via the downpipes 10. As a result, the free cross-section is increased for the ascending gaseous phase G, so that this advantageously hinders the downflowing liquid phase F less.

Another advantage of the solution according to the invention is that a

Conventional heat exchanger can be easily retrofitted with the downpipes 10 according to the invention if necessary.

LIST OF REFERENCE NUMBERS

1 heat exchanger

2 tube bundles

3 core tube

4 coat

4a inside

5 jacket space

6 gaps

10 downpipe

1 1 inlet opening

12 outlet opening

13 weir

20 pipe

30 flow path through core tube

100 pre-distributors

101 floor

102 side wall

104 supply line

105 outlet opening

106 Central opening

200 main distributor

201 distributor arm

202 floor

203 roof

204, 205 Lateral wall

206 Front wall

207 outlet opening

F Liquid phase

G Gaseous phase

S First medium

S 'second medium or two-phase mixture

Z longitudinal axis

Claims

claims

Heat exchanger (1), with:

a pre - distributor (100) for receiving a tube bundle (2) of the

Heat exchanger (1) to be distributed liquid phase (F),

- A along a longitudinal axis (Z) extended core tube (3), to which a

A plurality of tubes (20) which form the tube bundle (2),

- a main distributor (200) having a plurality of the core tube (3) projecting distributor arms (201) for distributing the liquid phase (F) on the tube bundle (2), wherein the distributor arms (201) via a in the core tube (3) extending flow path (30) with the pre-distributor (100) in

Fluid communication stand, so that the liquid phase (F) from the

Pre-distributor (100) via the flow path (30) in the distributor arms (201) of the main distributor (200) can be fed, characterized in that at least one distributor arm (201) via at least one along the longitudinal axis extending down pipe (10), outside the core tube (3), is in flow communication with the pre-distributor (100), so that the liquid phase to be distributed (F) via the at least one drop tube (10) from the pre-distributor (100) in the at least one distribution arm (201) can be fed.

Heat exchanger according to claim 1, characterized in that the

Heat exchanger (1) has a jacket (4) extending along the longitudinal axis (Z), which extends coaxially to the core tube (3), wherein the jacket (4) has a

Mantle space (5) surrounds, in which the pre-distributor (100), the main distributor (200), the tube bundle (2), the core tube (3) and the at least one drop tube (10) are arranged.

Heat exchanger according to claim 2, characterized in that the at least one drop tube (10) in a direction perpendicular to the longitudinal axis (Z) radial direction (R) is arranged further out than the core tube (3).

4. Heat exchanger according to one of the preceding claims, characterized in that the at least one downpipe (10) from above into a roof (203) of the associated distribution arm (201) opens.

5. Heat exchanger according to claim 2 or one of claims 3 to 4 so far

With reference to claim 2, characterized in that the respective distributor arm (201) starting from the core tube (3) in a direction perpendicular to the longitudinal axis (Z) radial direction (R) outwardly to a

Inner side (4a) of the jacket (4) extends.

6. Heat exchanger according to one of the preceding claims, characterized

characterized in that between each two adjacent distributor arms (201), a gap (6) for passing tubes (20) of the tube bundle (20) is provided.

7. Heat exchanger according to one of the preceding claims, characterized

in that the respective distributor arm (201) has a base (202) running perpendicular to the longitudinal axis (Z) and having a plurality

Having outlet openings (207), via which the liquid phase (F) on the below the respective distribution arm (201) arranged tube bundle (2) can be aufgebar.

8. Heat exchanger according to one of claims, characterized in that a distributor arm (201), a plurality of distributor arms (201) or all Verteilarme (201) via a plurality of along the longitudinal axis (Z) extending downpipes (10) with the pre-distributor (100 ) are in fluid communication.

9. Heat exchanger according to one of the preceding claims, characterized

characterized in that the heat exchanger (1) has a feed line (104) for a two-phase mixture (S) comprising the liquid phase (F), the feed line (104) having an outlet opening (105) along the longitudinal axis

(Z) above a baffle plate (103) of the pre-distributor (100) is arranged.

10. Heat exchanger according to one of the preceding claims, characterized

in that the predistributor (100) has a bottom (101) extending perpendicularly to the longitudinal axis (Z), wherein the bottom (101) has a central opening (106), via which the bottom (101) is in fluid communication with the flow path (30) surrounding the core tube (3).

1 1. Heat exchanger according to claim 10, characterized in that the

Pre-distributor (100) via one at the bottom (101) provided inlet opening (1 1) of the respective downpipe (10) with the respective downpipe (10) in

Fluid communication with the inlet openings (1 1) are arranged around the central opening (106) around. 12. Heat exchanger according to one of the preceding claims, characterized

characterized in that the core tube (3) is configured to receive the load of the tubes (20) of the tube bundle (2).

13. A method for distributing a liquid phase (F) on a tube bundle (2) of a wound heat exchanger (1), in particular using a

Heat exchanger (1) according to one of the preceding claims, wherein a two-phase mixture (S ') comprising a liquid phase (F) and a gaseous phase (G) in a pre-manifold (100) of the heat exchanger (1) is given, so that the two-phase mixture ( S ') is calmed down and at least part of the gaseous phase (G) can outgas from the two-phase mixture (S'), the liquid phase (F) passing through a core tube (3) of the

Heat exchanger (1) extending flow path (30) in a plurality of distribution arms (201) of a main distributor (200) of the heat exchanger (1) is passed and from there to a tube bundle (2) of the heat exchanger (1), which is a plurality of on the core tube (3) wound tubes

(20), and wherein the liquid phase (F) from the pre-distributor (100) is additionally passed over at least one down along a longitudinal axis (z) extending downpipe (10) in a distribution arm (201) of the main distributor (200), wherein the at least one drop tube (10) outside of the core tube (3) extends.

14. The method according to claim 13, characterized in that the pre-distributor (100) with a distributor arm (201), a plurality of distributor arms (201) or all distributor arms (201) each have a plurality of downcomers (10) in

Flow connection is, wherein the liquid phase (F) from the pre-distributor (100) in addition via the respective plurality of downcomers (10) in the respective

Distributor arm (201) is passed.

15. The method according to claim 13 or 14, characterized in that the at least one downpipe (10) or the downpipes (10) in a direction perpendicular to the core tube (3) extending radial direction (R) are arranged further out than the core tube (3) ,