DE102016004606A1 - Process engineering plant and process for liquefied gas production - Google Patents

Abstract

A process plant (1) for producing liquefied gas, comprising a heat exchanger (2), a first compressor (4), a second compressor (5), a first suction line (25) only in fluid communication with the first compressor (4), which is connected to the heat exchanger (2), and a second suction line (26), which is only in fluid communication with the second compressor (5) and which is connected to the heat exchanger (2), wherein the first suction line (25) is not in fluid communication with the second suction line (26).

Description

The invention relates to a process engineering plant and a process for liquefied gas production.

A process plant for liquid gas production may include a compressor for compressing refrigerant, which is connected by means of a suction line with a heat exchanger of the plant. Alternatively, such a compressor arrangement may for example comprise two compressors, which are connected by means of two suction lines to the heat exchanger of the plant. In this case, the suction lines were previously led from the heat exchanger to a tee and merged there to form a common line. The common line can be divided before the compressors by another tee again in two lines, which are connected to the compressors.

Against this background, the object of the present invention is to provide an improved process plant.

Accordingly, a process plant for the production of liquefied gas is proposed. The process plant comprises a heat exchanger, a first compressor, a second compressor, a first suction line connected only in fluid communication with the first compressor and connected to the heat exchanger, and a second suction line connected only in fluid communication with the second compressor Heat exchanger is connected, wherein the first suction line is not in fluid communication with the second suction line.

The compressors can also be referred to as compressors. With the help of the compressors a mixed refrigerant can be compressed. The compressors can therefore also be referred to as MRC (mixed-refrigerant-cycle) compressors. By virtue of the fact that the suction lines are fluidically separated from one another or are not in fluid communication with one another, it is to be understood that no refrigerant can pass from the first suction line into the second suction line and vice versa. Further, it is to be understood that conveyed by the first suction refrigerant only the first compressor and the second suction line promoted refrigerant exclusively the second compressor for compression is provided. Each compressor is assigned a separate suction line. Under a fluidic connection of two components is to be understood that these components are in fluid communication. The process plant can be used except for the production of liquefied gas for other configurations having a common starting point, such as a container, a column, a reactor, a heat exchanger or the like, and in which a symmetrical piping to parallel operated compressors required is. A method for liquefying a hydrocarbon-rich stream is in the EP 0 975 923 B1 described. This process can be carried out with the claimed process plant.

In the case of a compressor selection, which can not provide sufficient compressor power to supply the central heat exchanger completely, the number of compressors must be increased accordingly. Characterized in that each compressor is assigned its own suction, can be dispensed tees for unifying the suction lines to the heat exchanger and again separating the suction lines in front of the compressors. As a result, unnecessary pressure losses can be prevented on the suction side of the compressors. Furthermore, the fact that no T-pieces, a very flexible installation of the suction lines is possible, which provides the planning planning for the entire system essential planning degrees of freedom. As a result, the compressors can be placed very close to the heat exchanger, since no elaborate arcs for dissipation of thermal voltages are required. Furthermore, can be integrated directly through the separate cable management of the suction long inlet and outlet sections for a flow measurement without having to lay loops in order to incorporate these in limited building windows. This problem comes especially with larger diameters of the suction line to bear, as the inlet and outlet sections are given as a multiple of the pipe cross-section. These inlet and outlet sections can be several tens of meters.

According to one embodiment, the process plant comprises a first suction container, which is arranged between the first compressor and a first suction line section of the first suction line, and a second suction container, which is arranged between the second compressor and a first suction line section of the second suction line.

The suction containers can also be referred to as suction bottles. Preferably, the suction containers are cylindrical. The first Saugleitungsabschnitte are each flanged to their associated suction containers.

Another embodiment provides the absence of the suction container with sufficient Overheating of the incoming fluid, which leads to a prevention of dripping on the suction side of the compressor and thus makes a suction container superfluous. This is a general embodiment, but is not used in gas liquefaction plants for practical reasons. Above all, the collection of refrigerant at standstill is an important task of the suction container.

According to a further embodiment, a second suction line section of the first suction line is arranged between the first compressor and the first suction container, and a second suction line section of the second suction line is arranged between the second compressor and the second suction container.

The second suction line sections may be as short as possible. As a result, pressure losses can be prevented.

According to another embodiment, the second suction line section of the first suction line is the same length as the second suction line section of the second suction line.

This results in a symmetrical structure of the process plant. As a result, both compressors are equally loaded during operation of the process plant.

According to another embodiment, the second suction line section of the first suction line and the second suction line section of the second suction line are straight.

Under straight is to be understood that the Saugleitungsabschnitte are curvature and / or arc-free.

According to a further embodiment, the first suction line section of the first suction line is the same length as the first suction line section of the second suction line.

As a result, both compressors are charged equally during operation of the process plant. A higher wear or a shortened life of one of the compressors can thereby be reliably prevented. As a result, the maintenance costs are reduced. In particular, this can also result in no unequal distribution of the refrigerant to the compressors, which otherwise could cause an unstable operating behavior of the process plant.

According to a further embodiment, the first suction line and the second suction line are free of devices which are arranged to divide and / or to unite fluid streams, in particular free of T-pieces.

That is, neither in the first suction line nor in the second suction line, a T-piece is installed, which serves to distribute the main currents. Recirculation within a compressor assembly (suction, suction, compressor stages, pressure lines) are unaffected. A T-piece is to be understood as meaning a pipe section which is arranged to combine two lines into one or divide a line into two. By dispensing with T-pieces, occurring pipe stresses can be reduced in the designed temperature range, that is, plus degrees and low minus degrees in the operating state, since no mechanical fixing takes place by means of tees. Temperature-induced material expansions are not hindered by this.

According to another embodiment, the first suction line section of the first suction line and the first suction line section of the second suction line are straight.

Preferably, the first suction line section is arranged in each case in a line with the second suction line section.

According to a further embodiment, the procedural system is constructed symmetrically to a central axis of the heat exchanger.

In particular, the compressor assembly is mirror-symmetrical to a plane passing through the central axis of symmetry plane. This results in a particularly simple construction of the process plant. Furthermore, this can eliminate the main influence factor for an unequal distribution on the various compressors.

According to another embodiment, the compressor assembly comprises a plurality of compressors and a plurality of suction lines.

For example, the compressor assembly may include three, four, five, six or more compressors, first suction line sections, suction vessels, and second suction line sections.

According to a further embodiment, the compressors and / or the suction lines are arranged distributed uniformly around the heat exchanger.

For example, the compressors, first Saugleitungsabschnitte, suction and / or second Saugleitungsabschnitte are arranged on a circulating the heat exchanger circuit. In particular, the compressors, first Saugleitungsabschnitte, suction and / or second Saugleitungsabschnitte are evenly distributed around a circumference of the heat exchanger

According to a further embodiment, the compressors and / or the suction lines are arranged in a star shape.

As a result, the compressors can be placed as close to the heat exchanger, whereby pressure losses can be prevented. This increases the efficiency of the process plant or it can be reduced, the required compressor power.

According to a further embodiment, first suction line sections of the suction lines are all the same length, wherein second suction line sections of the suction lines are all the same length.

As a result, all compressors are loaded equally during operation of the process plant. A higher wear or a shortened life of one of the compressors can thereby be reliably prevented. This reduces the maintenance effort and minimizes the risk of unstable driving.

According to one embodiment, the heat exchanger is a helical heat exchanger.

In particular, the heat exchanger may be a spirally wound heat exchanger. Spiral wound heat exchangers can be used for a wide range of fluid handling applications. They can cover a wide temperature and pressure range and are suitable for both single-phase and two-phase flows. In a wound heat exchanger several, for example three, heat exchanger tube layers can be wound on a core and surrounded by a jacket.

Furthermore, a method for producing liquefied gas is proposed with such a process plant.

Other possible implementations of the process plant and / or of the method also include combinations not explicitly mentioned of features or embodiments described above or below with regard to the exemplary embodiments. The expert will also add individual aspects as improvements or additions to the respective basic form of the process plant and / or the process.

Further advantageous embodiments and aspects of the process plant and / or of the method are the subject matter of the subclaims and the exemplary embodiments of the process plant and / or method described below. Furthermore, the process engineering system and / or the method will be explained in more detail on the basis of preferred embodiments with reference to the enclosed figures.

1 shows a schematic perspective view of an embodiment of a process plant;

2 shows a schematic view of the process plant according to 1 ;

3 shows a schematic view of another embodiment of a process plant; and

4 shows a schematic partial sectional view of an embodiment of a heat exchanger for the process plant according to 1 or 3 ,

In the figures, the same or functionally identical elements have been given the same reference numerals, unless stated otherwise.

The 1 shows a schematic perspective view of an embodiment of a process plant 1 , The 2 shows a schematic view of the process engineering equipment 1 , The following is on the 1 and 2 simultaneously referred to.

The process engineering plant 1 may be a process plant for the production of liquefied natural gas (LNG). As LNG is denoted by cooling to -164 to -161 ° C liquefied natural gas. The process engineering plant 1 includes a heat exchanger 2 , The heat exchanger 2 may be a so-called wound or helical heat exchanger 2 be. Here, several, for example three, Wärmeübertragerrohrlagen are wound on a core and surrounded by a jacket. The heat exchanger 2 can be constructed rotationally symmetrical to a symmetry or central axis M ₂ .

The process engineering plant 1 can be a compressor arrangement 3 include. The compressor arrangement 3 includes at least a first compressor or compressor 4 and a second compressor or compressor 5 , The compressor arrangement 3 can also have more than two compressors 4 . 5 include. Furthermore, the compressor arrangement comprises 3 a first suction bottle or a first suction container 6 , the first compressor 4 is assigned, and a second suction bottle or a second suction container 7 , the second compressor 5 assigned. The first compressor 4 is with the help of a first suction line 25 with the heat exchanger 2 in fluid communication and the second compressor 5 is with the help of a second suction line 26 with the heat exchanger 2 in fluid communication.

The first suction container 6 is by means of a first Saugleitungsabschnitts 8th the first suction line 25 with the heat exchanger 2 fluidly connected. The second suction container 7 is by means of a first Saugleitungsabschnitts 9 the second suction line 26 fluidic with the heat exchanger 2 connected. That is, it is for every compressor 4 . 5 a separate suction line 25 . 26 and a separate suction container 6 . 7 intended. The compressors 4 . 5 are each using a second Saugleitungsabschnitts 10 the first suction line 25 and a second suction line section 11 the second suction line 26 with their associated suction containers 6 . 7 fluidly connected. The suction lines 25 . 26 For example, they may have a diameter of 40 inches. Preferably, the compressor assembly 3 constructed symmetrically to the central axis M ₂ and in particular mirror-symmetrical to a plane of symmetry E. The center axis M ₂ lies in the plane of symmetry E. The first suction line sections 8th . 9 and the second suction line sections 10 . 11 are as straight as possible, that is, without bends or curves executed.

In the case of a compressor choice, which can not provide sufficient compressor power to the central heat exchanger 2 to supply completely, is the number of compressors 4 . 5 increase accordingly. By doing that every compressor 4 . 5 its own suction line 25 . 26 can be assigned to facilities that are adapted to split and unify fluid streams, in particular T-pieces for unifying the suction lines 25 . 26 after the heat exchanger 2 and to disconnect the suction lines again 25 . 26 in front of the compressors 4 . 5 , be waived. This allows on a suction side of the compressors 4 . 5 unnecessary pressure losses are prevented. Furthermore, the fact that there is no need for tees, a very flexible installation of the suction lines 25 . 26 possible, which provides the design planning for the entire system essential planning degrees of freedom. This allows the compressors 4 . 5 very close to the heat exchanger 2 be placed because no elaborate arches for dissipation of thermal voltages are required. Furthermore, by the separate wiring of the suction lines 8th . 9 long inlet and outlet sections for a flow measurement must be directly integrated without having to lay pipe loops in order to integrate them into limited building windows. This problem arises above all with larger nominal widths of the suction lines 25 . 26 to bear because the inlet and outlet sections are given as a multiple of the pipe cross-section.

By dispensing with tees in the suction lines 8th . 9 can be reduced in the designed temperature range, that is, plus degrees in the start-up state and low minus degrees in the operating state, occurring pipe stresses, as no mechanical determination by T-pieces. Temperature-induced material expansion and material shrinkage are not hindered by this. With the help of the compressor arrangement 3 can, as previously mentioned, pressure losses on the suction side of the compressors 4 . 5 through a more flexible and shortened piping of the suction lines 25 . 26 and the saving of tees in merging and separating multiple streams can be prevented.

By reducing pressure losses on the suction side of the compressors 4 . 5 can the required power of the compressors 4 . 5 be reduced or the liquefaction capacity of a LNG plant be increased. This is, on the one hand, a direct consequence of the saving of two T-pieces, which result in an unnecessary dynamic pressure loss as a result of the flow deflection, and, on the other hand, a consequence of the feasibility of shortened tube lengths with fewer bends of the suction lines 25 . 26 , When piping the suction pipes 25 . 26 constructively provides more freedom in piping and the derivation of pipe stresses, especially for larger nominal sizes available.

The 3 shows a highly simplified schematic view of another embodiment of a process plant 1 , The process engineering plant 1 according to the 3 differs from the process plant 1 according to the 1 and 2 essentially by the fact that the compressor assembly 3 not just two compressors 4 . 5 , two suction lines 25 . 26 and two suction cups 6 . 7 but five compressors 4 . 5 . 13 . 14 . 15 , five suction lines 25 to 29 with first suction line sections 8th . 9 . 19 . 20 . 21 and five suction cups 6 . 7 . 16 . 17 . 18 , which has five second suction line sections 10 . 11 . 22 . 23 . 24 fluidic with the compressors 4 . 5 . 13 . 14 . 15 are connected. The number of compressors 4 . 5 . 13 . 14 . 15 is arbitrary, it can also be three, six, eight or ten compressors 4 . 5 . 13 . 14 . 15 be provided. In particular, the suction container 6 . 7 . 16 . 17 . 18 and / or the compressors 4 . 5 . 13 . 14 . 15 evenly over a circumference of the heat exchanger 2 arranged distributed. Preferably, this results in a symmetrical structure of the process plant 1 in which all suction lines 25 to 29 have the same length. In particular, the process plant 1 thereby have a star-shaped arrangement.

The compressor arrangement 3 and in particular the piping with the suction lines 25 to 29 can also be used for other configurations having a common starting point, such as a container, a column, a reactor, a heat exchanger or the like, and in which a symmetrical piping to parallel operated compressors is required.

The 4 shows in a schematic partial sectional view of an embodiment of a helical heat exchanger 2 for the process plant 1 , The heat exchanger 2 includes a coat 30 in which a core 31 is included. On the core 31 are several layers of heat exchanger tubes 32 wound up, of which in the 4 only one is provided with a reference numeral. The mixed refrigerant is the heat exchanger 2 over a line 33 supplied, trickles down in a direction of gravity g, whereby it evaporates and that through the heat exchanger tubes 32 cool down natural gas. The refrigerant flow is in the 4 with arrows 34 . 35 designated. Over several lines 36 or a line 36 the mixed refrigerant is withdrawn and the compressors 4 . 5 fed. The natural gas that is in the 4 with arrows 37 . 38 is designated, is opposite to the direction of gravity g through the heat exchanger 2 guided.

Although the present invention has been described with reference to embodiments, it is variously modifiable.

LIST OF REFERENCE NUMBERS

1

Process engineering plant

2

heat exchangers

3

compressor assembly

4

compressor

5

compressor

6

suction tank

7

suction tank

8th

suction line

9

suction line

10

suction line

11

suction line

13

compressor

14

compressor

15

compressor

16

suction tank

17

suction tank

18

suction tank

19

suction line

20

suction line

21

suction line

22

suction line

23

suction line

24

suction line

25

suction

26

suction

27

suction

28

suction

29

suction

30

coat

31

core

32

heat exchanger tube

33

management

34

arrow

35

arrow

36

management

37

arrow

38

arrow

e

plane of symmetry

G

The direction of gravity

M ₂

central axis

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0975923 B1 [0005]

Claims (15)

Process engineering plant ( 1 ) for producing liquefied gas, with a heat exchanger ( 2 ), a first compressor ( 4 ), a second compressor ( 5 ), one in fluid communication with the first compressor ( 4 ) standing first suction line ( 25 ) connected to the heat exchanger ( 2 ) and only in fluid communication with the second compressor ( 5 ) standing second suction line ( 26 ) connected to the heat exchanger ( 2 ), wherein the first suction line ( 25 ) not in fluid communication with the second suction line ( 26 ). Process engineering plant according to claim 1, comprising a first suction container ( 6 ) between the first compressor ( 4 ) and a first suction line section ( 8th ) of the first suction line ( 25 ) is arranged, and a second suction container ( 7 ) between the second compressor ( 5 ) and a first suction line section ( 9 ) of the second suction line ( 26 ) is arranged. Process plant according to claim 2, wherein between the first compressor ( 4 ) and the first suction container ( 6 ) a second suction line section ( 10 ) of the first suction line ( 25 ) and between the second compressor ( 5 ) and the second suction container ( 7 ) a second suction line section ( 11 ) of the second suction line ( 26 ) is arranged. Process engineering plant according to claim 3, wherein the second suction line section ( 10 ) of the first suction line ( 25 ) of the same length as the second suction line section ( 11 ) of the second suction line ( 26 ). Process plant according to claim 3 or 4, wherein the second suction line section ( 10 ) of the first suction line ( 25 ) and the second suction line section ( 11 ) of the second suction line ( 26 ) are straight. Process engineering plant according to one of claims 2-5, wherein the first suction line section ( 8th ) of the first suction line ( 25 ) of the same length as the first suction line section ( 9 ) of the second suction line ( 26 ). Process engineering plant according to one of claims 1-6, wherein the first suction line ( 25 ) and the second suction line ( 26 ) free of devices which are adapted to split and / or unify fluid streams, in particular free of tees. Process plant according to one of claims 1-7, wherein the first suction line section ( 8th ) of the first suction line ( 25 ) and the first suction line section ( 9 ) of the second suction line ( 26 ) are straight. Process engineering plant according to one of claims 1-8, wherein the process plant ( 1 ) symmetrical to a central axis (M ₂ ) of the heat exchanger ( 2 ) is constructed. Process plant according to one of claims 1-9, comprising a plurality of compressors ( 4 . 5 . 13 . 14 . 15 ) and a plurality of suction lines ( 25 - 29 ). Process engineering plant according to claim 10, wherein the compressors ( 4 . 5 . 13 . 14 . 15 ) and / or the suction lines ( 25 - 29 ) evenly around the heat exchanger ( 2 ) are arranged distributed. Process engineering plant according to claim 11, wherein the compressors ( 4 . 5 . 13 . 14 . 15 ) and / or the suction lines ( 25 - 29 ) are arranged in a star shape. Process engineering plant according to one of claims 10-12, wherein first suction line sections ( 8th . 9 . 19 . 20 . 21 ) of the suction lines ( 25 - 29 ) are all the same length and wherein second suction line sections ( 10 . 11 . 22 . 23 . 24 ) of the suction lines ( 25 - 29 ) are all the same length. Process engineering plant according to one of claims 1-13, wherein the heat exchanger ( 2 ) is a helical heat exchanger. Process for producing liquefied petroleum gas using a process plant ( 1 ) according to any one of claims 1-14.

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