DE202016102555U1 - Shut-off device for an ethylene production plant and ethylene production plant - Google Patents

Abstract

Shut-off device for an ethylene production plant, in particular slit gas slide or decoking slide, with at least one slide plate (11) arranged concentrically in a plate basket (10) and connected to a slide rod (14) and a pipe bridge (12), each between guide plates (13) are movable to shut off or open a line connected to pipe socket (17) of the obturator by operating the slide rod (14), wherein between the at least one slide plate (11) and / or the pipe bridge (12) on the one side and each associated pipe socket (17) on the other side sealing seats (18, 19) are defined, at which in the closed state of the obturator the at least one slide plate (11) and the associated pipe socket (17) and in the open state of the obturator the pipe bridge (12) and the associated pipe socket (17) rest, characterized in that - the at least one slide plate (11) in Ric to the respective associated pipe socket (17) and / or the pipe socket (17) in the direction of the respective associated slide plate (11) or, depending on whether closed or open state of the pipe bridge (12) and / or - the pipe bridge (12 ) has in the direction of the respective associated pipe socket (17) in the region of the respective sealing seats (18, 19) at least one sealing ring receptacle in the form of a recess or recess for receiving at least one sealing ring / have.

Description

The invention relates to a shut-off device, in particular a slide valve or double plate slide, for an ethylene production plant according to the preamble of patent claim 1 and such a plant according to the preamble of claim 12.

Ethylene is made by thermal cracking of long chain hydrocarbons, such as naphtha, using steam by the so-called "steam cracking" method. In this process, the hydrocarbon raw material is mixed with steam, heated and placed in a cracking furnace, in which the so-called "cracking" takes place.

The raw gas leaving the cracking furnace is conducted with its fission products through a product main line called "Main Transfer Line" into connected systems for further processing.

In the course of this production process, coke residues accumulate which reduce the free cross-section of the pipes. In order to eliminate these disturbing residues, the system must be decocted at intervals. For this purpose, the plant is switched from the production plant in the so-called "decoking" and rinsed with an air / water vapor mixture, which is blown along with dissolved coke residues on a decoking line, the so-called "Decoke Line".

During production, the Entkokungsleitung is shut off by a first obturator and the transfer line opened by a second obturator. In Entkokungsbetrieb conversely, the first obturator is opened in the Entkokungsleitung and the second obturator in the transfer line closed.

In the course of a switching operation between the production operation and the decoking operation, a critical process phase usually occurs in which a backflow of hydrocarbons via the second shut-off device in the transfer line must be avoided. This is achieved by actuating the two shut-off elements in the transfer line and the decoking line in a coordinated manner. It depends on a good tightness and reliable opening and closing function of the respective shut-off. As shut-off devices are therefore usually slider, so-called. Spaltgasschieber and Entkokungsschieber used.

So-called valve gate valves and in particular "double plate tube bridge valves", whose basic principle is based on a technology developed by the applicant and which are also used in other areas of the petrochemical industry as a special fitting, have proven particularly suitable for use in ethylene production plants.

A challenge with shut-off devices of this type is on the one hand to produce a good sealing effect and on the other hand to allow the easiest possible accessibility during opening and closing, so that the obturator, or the slider, can be safely and reliably operated. Different concepts are available for this. For example, sprung sealing seats are installed on the inside of the pipe flanges, which allow precise setting of a defined sealing force on the slide plates or the pipe bridge. Sprung sealing seats are for example in EP 2 241 792 A2 and DE 197 23 962 A1 which also go back to the Applicant. The EP 1 561 180 B1 also discloses a sealing seat, which rests under the action of an elastic element in the closed position at the periphery of a shut-off plate and in the open position on a pipe bridge. These systems work well, but are very expensive in terms of their construction and require a high level of maintenance.

Another disadvantage of these known systems, or shut-off valves, is further that the local sealing seats are subjected to very high wear and thus maintaining a good sealing effect over time and especially under the extreme reaction conditions in an ethylene production plant is problematic. A maintenance of these known systems for restoring or improving their tightness is also possible only by replacing complete assemblies, such as the slide valve or the pipe bridge. Such a procedure is extremely complicated and expensive.

The object of the invention is to provide a shut-off device which avoids the abovementioned disadvantages and, in particular when used in an ethylene production plant, ensures a good and reliable sealing effect over a long period of time and reliable operation and a simple, cost-effective and reliable operation Maintenance allows. In addition, the invention further has the object of an ethylene production plant with such a shut-off device.

This object is achieved by a shut-off device according to claim 1, by an ethylene production plant according to claim 12 and a A method for operating such a system according to claim 12 solved.

• – die wenigstens eine Schieberplatte in Richtung zu dem jeweils zugeordneten Rohrstutzen und/oder
• – der Rohrstutzen in Richtung der jeweils zugeordneten Schieberplatte oder, je nachdem, ob geschlossener oder offener Zustand der Rohrbrücke und/oder
• – die Rohrbrücke in Richtung zu dem jeweils zugeordneten Rohrstutzen

im Bereich der jeweiligen Dichtsitze wenigstens eine Dichtringaufnahme in Form einer Ausnehmung oder Aussparung zur Aufnahme wenigstens eines Dichtrings aufweist/aufweisen. In particular, the object is achieved by a shut-off device, in particular plate slide or double plate slide, for an ethylene production plant, in particular Spaltgasschieber or Entkokungsschieber, with at least one slide plate which is arranged concentrically in a plate basket and connected to a slide rod and a pipe bridge, which are each movable between guide plates, in order to shut off or open a line connected to pipe stubs of the obturator by actuating the slide rod, wherein between the at least one slide plate and / or the pipe bridge on the one side and the respectively assigned pipe stub on the other side sealing seats are defined, in which closed state of the obturator, the at least one slide plate and the associated pipe socket and in the open state of the obturator bear the pipe bridge and the associated pipe socket, wherein

• - The at least one slide plate in the direction of the respective associated pipe socket and / or
• - The pipe socket in the direction of the respective associated slide plate or, depending on whether closed or open state of the pipe bridge and / or
• - The pipe bridge in the direction of the respectively associated pipe socket

has in the region of the respective sealing seats at least one sealing ring receptacle in the form of a recess or recess for receiving at least one sealing ring / have.

An important point of the invention is to provide a shut-off device which can be used as a plate slide or double plate slide, in particular for an ethylene production plant. This may in particular be a split gas slide or a decoking slide. In the case of the execution of the obturator as a double plate slide has this concentrically arranged in a plate basket slide plates and a pipe bridge, which are movable between guide plates for shutting off and opening a line by operating a slide rod. Between the slide plates, a spreading member is arranged, which is connected to the slide rod. The pipe bridge further comprises a Kompensatoreinheit. The slide plates or the pipe bridge are in the closed or open position on sealing seats.

Another important point of the invention is further that at least one sealing ring receptacle is provided in the region of the respective sealing seats. This sealing ring receptacle can be designed in the form of a recess or recess, which is suitable for receiving and releasably securing at least one sealing ring.

A significant advantage of the invention thus consists in that the obturator according to the invention has sealing seats arranged in the form of sealing rings on the slide plate and / or the pipe bridge and / or on their respective counterpart, namely the respectively associated pipe socket, and there releasably are attached.

The essential advantage associated with the invention thus consists in the fact that the respective sealing ring forming a tight fit, if necessary, i. in the case of wear, is interchangeable, so that it is made possible by the present invention, only the tightness of the obturator ensuring components, namely the or the sealing rings, the slide plate, pipe bridge or the pipe socket to replace, without the need for a complete replacement of slide plate , Pipe bridge or pipe socket, and thus in fact the entire valve slide, consists.

In the context of the invention, it is possible that the replaceable sealing ring is arranged only concentrically around the circumference of the slide plate around. Alternatively or additionally, the sealing ring can also on the opposite side of the slide plate of the obturator, i. be arranged on the pipe socket. In exceptional cases, a provision of a respective sealing ring on the slide plate and on the pipe socket according to the invention is possible. In an analogous manner, a replaceable sealing ring according to the invention can also be arranged on the pipe bridge and / or in the open state of the obturator, cooperating with the pipe bridge pipe socket.

According to one embodiment of the invention, the sealing ring is fixed by means of at least three welding points in the sealing ring receptacle, which are arranged substantially uniformly around a, preferably outer, circumference of the slide plate. For this purpose, the sealing ring receptacle is formed as a recess, which is formed, for example, rectangular in a pipe socket facing edge of the slide plate. This stepped or step-shaped recess in the slide plate edge is suitable for receiving a complementarily shaped sealing ring having such a shape that it is exactly in the staircase or step-shaped recess and fits substantially flush with the pipe socket facing surface of the slide plate or protrudes slightly beyond this surface.

An attachment of the sealing ring in the recess, as mentioned above about welding points or a continuous weld, which are preferably arranged along the outer circumference of the slide plate, or the sealing ring, is / is. The number of welds is inventively chosen so that they are evenly distributed over the circumference of the slide plate and ensure a secure fit and hold of the sealing ring in the recess. In order to release the sealing ring according to the invention from the slide plate, only an opening of the weld, for example by means of a welding torch or by means of flexing, is necessary.

In accordance with the invention analogous manner, the sealing ring can also be arranged in a correspondingly shaped recess on the pipe socket associated with the slide plate. The same applies to the attachment of the sealing ring to the pipe bridge. In this context, it should be noted that instead of a recess in an edge of the respective component in principle, an attachment of the sealing ring in a recess of the respective component is possible, said recess may be formed, for example, groove-shaped. In this case, the attachment of welds or a weld in the sealing surface itself is necessary, in which case the respective weld is smoothed after the attachment of the sealing ring in the recess and optionally polished.

According to a further embodiment of the invention, the sealing ring can be screwed in the sealing ring receptacle alternatively or additionally, wherein the respective screw head is preferably countersunk in a respective countersunk hole, which is provided in the sealing ring, so that the screw head does not protrude beyond the surface of the sealing ring, if the screw is screwed in from the later sealing side.

According to an alternative embodiment of the invention, the sealing ring may also be screwed starting from the periphery thereof. In this case, a screw is guided by a screw hole provided in the seal ring, which is arranged in the peripheral periphery of the sealing ring, and screwed laterally into the slide plate and fixed there. In such a lateral attachment of a fastening screw a countersinking of the screw head is not necessary, since the respective screw head does not protrude in this case in the region of the sealing seat. In an analogous manner, the sealing ring according to the invention can also be fixed to the pipe socket and / or to the pipe bridge. In this connection, it should also be pointed out that, according to the invention, a multiplicity of fastening screws distributed substantially uniformly around the circumference of the respective sealing ring are used for fixing the sealing ring.

A Schraubbefestigung the sealing ring on the slide plate and / or the pipe socket and / or the pipe bridge is particularly advantageous that such Schraubbefestigung simply accomplish and, for the replacement of the sealing ring, very easy to solve again.

According to a further embodiment of the invention, the sealing ring in the sealing ring receptacle may alternatively or additionally be glued to a high temperature resistant adhesive. Such bonding of the sealing ring in the sealing ring receptacle can either, preferably over the entire surface, be provided along the entire contact surface of the sealing ring with the slide plate and / or the pipe socket and / or the pipe bridge or only selectively.

Furthermore, the sealing ring according to the invention may be composed of segments which are braced against each other and each other when the sealing ring is inserted into the sealing ring receptacle. According to the invention, the sealing ring can thus be designed in two parts, for example, wherein each segment of the sealing ring is formed semi-annular. These two segments are then used from both sides toward each other in the sealing ring receptacle and braced against each other for example by means of tangentially inserted screws or a tension band.

According to a particularly advantageous embodiment of the invention, the sealing ring receptacle in this case, one or more undercut (s) have, in which engage respective projections of the sealing ring and fix the sealing ring with respect to a flow direction, respectively of the pipe socket, axial direction.

According to the invention, the segments, in particular in an axial direction to the pipe socket, formed overlapping each other. In this way, both a good mutual fixation of the sealing ring segments and a good sealing effect can be ensured.

Furthermore, according to the invention, the sealing ring has, on its side facing the respective sealing seat, an armoring which extends in particular over possibly existing countersunk holes. This armor and / or the sealing ring itself furthermore have, according to the invention, a hardened and / or polished sealing surface.

Particularly effective and low maintenance is an embodiment of the obturator, in which a arranged on the pipe bridge Kompensatoreinheit and the sealing seats each form a metal seal. This type of gaskets has proven particularly useful in the operation of ethylene manufacturing plants.

Such Kompensatoreinheit may also have hardened sealing surfaces, which are in contact with the guide plates. As a result, the wear of the pipe bridge is reduced when opening and closing the slide.

The invention is further based on the idea of providing an ethylene production plant with a cracking furnace which is operable in a production mode and a decoking mode. A first shut-off device according to the invention is in a transfer line and a second shut-off device according to the invention is arranged in a decoking line. The first and the second obturator invention are mutually movable in an open and closed position. The first and / or second obturator according to the invention may each be designed as a plate slide, or preferably double plate slide, according to the above statements.

In the context of the invention, furthermore, a method for operating an ethylene production plant is disclosed and claimed in which a first shut-off device according to the invention is closed in a transfer line for fission gas, which is connected to a cracking furnace, and at the same time a second shut-off device according to the invention is opened in a decoking line, which is connected to the transfer line. The first and / or second obturator according to the invention may each be designed as a plate slide, or preferably double plate slide, according to the above statements.

The invention will be explained in more detail below with reference to the accompanying single schematic figure with further details.

The single FIGURE shows a section of a double plate tube bridge slide according to an embodiment of the invention. Such a slide is used in ethylene production plant and is also referred to as Spaltgasschieber or Entkokungsschieber.

The slider has a housing 23 on top of that in the case 23 located internals fluid-tight surrounds. With the housing 23 connected, in particular welded are two pipe sockets 17 , Which are arranged in the flow direction front or rear of the slider. The pipe socket 17 are flanged in the assembled state to corresponding lines (not shown), for example, a transfer line or a decoking line.

The slider also references a disk tray 10 on, in the slide plates 11 are inserted. The slide plates 11 are arranged concentrically and parallel to each other and close in the illustrated closed position, the two pipe sockets 17 from. The slide plates 11 are loose in the disk basket 10 inserted so that they in the axial direction, ie perpendicular to the surface of the slide plates 11 are movable. This is used to the slide plates 11 in the closed position to the housing 23 provided sealing seats 18 . 19 to press, which are formed by releasable sealing rings (not shown). This is a spreading organ 15 between the two slide plates 11 arranged, with a slide bar 14 connected is. The slider bar 14 is fluid-tight in the housing 23 stored and by a (not shown) drive in the longitudinal direction movable. The spreading organ 15 has an inner wedge 20 up in an outer wedge 21 on the inside of the slide plates 11 is arranged. For centering the spreading 15 is between the jaws of the inner wedge 20 a centering ball 22 arranged.

Upon actuation of the slide rod 14 becomes the inner wedge 20 in the outer wedge 21 moved into it, causing the two slide plates 11 be spread apart. Due to the spreading movement, the two slide plates against the sealing seats 18 . 19 pressed, whereby a good sealing effect is achieved in the closed position of the slide.

Below or next to the plate basket 10 is a pipe bridge 12 arranged in the open position (not shown) with the two pipe sockets 17 flees. The pipe bridge 12 is with the disk basket 10 connected so that these together with the disk tray 10 by an actuation of the slide rod 14 can be moved into the open or closed position. To do this, the disk tray 10 and the pipe bridge 12 between two parallel guide plates 13 emotional.

The pipe bridge 12 also has a compensator unit 16 whose height is the total height of the pipe bridge 12 certainly. The compensator unit 16 has two compensator rings 24 . 25 on, which are arranged concentrically and spaced apart from each other in the axial direction. Between the two sealing rings 24 . 25 is a compensator shaft 28 arranged. This is designed mehrwellig in the present embodiment. Single-shaft compensator shafts are also possible, especially with smaller nominal diameters.

The compensator shaft 28 includes an inner pipe section 26 and an outer tube section 27 which are arranged coaxially. The inner pipe section 26 is aligned with the inner surfaces of the invention releasably secured sealing rings 24 . 25 so that a substantially smooth flow passage through the pipe bridge is ensured.

The height of the compensator unit 16 or the pipe bridge 12 is from the sealing surface of a Kompensatorrings 24 to the sealing surface of the other compensator ring 25 measured. The height of the compensator unit 16 refers to the clearance between the sealing seats 18 . 19 an oversize which is in a range of 0.5 mm to 1.60 mm. This oversize ensures that the compensator unit 16 or the pipe bridge 12 with a sufficiently large sealing force against the sealing seats 18 . 19 is pressed in the open position of the slider.

In the event that the sealing force decreases with increasing operating time, are on the outside of Kompensatoreinheit 16 several disc spring columns 17 intended. For example, you can 3 . 4 . 5 or 6 Disc spring stacks 17 on the outer circumference of the Kompensatoreinheit 16 be arranged distributed. The bias of the disc spring columns, specifically the Vorspannweg is per column 1 mm to 4 mm. Each disc spring column can contain 8 to 12 disc springs.

The number of disc spring column in or the number of disc springs per column depends on the nominal diameter of the slider.

It should be noted at this point that all of the parts described above are considered to be essential to the invention and in every combination, in particular the details shown in the drawings, as essential to the invention. Variations thereof are familiar to the person skilled in the art.

LIST OF REFERENCE NUMBERS

LIST OF REFERENCE NUMBERS

10

plate basket

11

slide plates

12

Rohrbrücke

13

baffles

14

slide rod

15

spreading member 15

16

compensator

17

pipe socket

18

sealing seat

19

sealing seat

20

internal wedge

21

external spline

22

centering ball

23

casing

24

Kompensatorring

25

Kompensatorring

26

inner pipe section

27

outer tube section

28

Kompensatorwelle

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 2241792 A2 [0008]
• DE 19723962 A1 [0008]
• EP 1561180 B1 [0008]

Claims (12)

Shut-off device for an ethylene production plant, in particular slit gas slide or decoking slide, with at least one slide plate ( 11 ) concentrically in a plate basket ( 10 ) and with a slide rod ( 14 ) and a pipe bridge ( 12 ), each between guide plates ( 13 ) are movable to one on pipe socket ( 17 ) of the obturator connected by actuation of the slide rod ( 14 ) shut off or open, wherein between the at least one slide plate ( 11 ) and / or the pipe bridge ( 12 ) on the one side and the respective associated pipe socket ( 17 ) on the other side sealing seats ( 18 . 19 ) are defined at which in the closed state of the obturator the at least one slide plate ( 11 ) and the associated pipe socket ( 17 ) and in the open state of the obturator, the pipe bridge ( 12 ) and the associated pipe socket ( 17 ) abuts, characterized in that - the at least one slide plate ( 11 ) in the direction of the respective associated pipe socket ( 17 ) and / or - the pipe socket ( 17 ) in the direction of the respective associated slide plate ( 11 ) or, depending on whether closed or open state of the pipe bridge ( 12 ) and / or - the pipe bridge ( 12 ) in the direction of the respective associated pipe socket ( 17 ) in the region of the respective sealing seats ( 18 . 19 ) has at least one sealing ring receptacle in the form of a recess or recess for receiving at least one sealing ring / have. Shut-off device according to claim 1, characterized in that the sealing ring is detachably fastened in the sealing ring receptacle. Shut-off device according to claim 2, characterized in that the sealing ring is fastened by means of at least three welding points in the sealing ring receptacle, which are arranged substantially uniformly around a, preferably outer, circumference of the sealing ring. Shut-off device according to one of the preceding claims 2 to 3, characterized in that the sealing ring is screwed into the sealing ring receptacle. Shut-off device according to claim 4, characterized in that the sealing ring has a countersunk hole for countersinking a respective screw head. Shut-off device according to one of the preceding claims 2 to 5, characterized in that the sealing ring is glued in the sealing ring receptacle. Shut-off device according to one of the preceding claims, characterized in that the sealing ring is composed of segments which are clamped to one another in, inserted into the sealing ring receptacle state. Shut-off device according to claim 7, characterized in that the sealing ring receiving an undercut, in which engages a projection of the sealing ring. Shut-off device according to one of the preceding claims 7 to 8, characterized in that the segments, in particular in an axial direction to the pipe socket, are formed overlapping each other. Shut-off device according to one of the preceding claims, characterized in that the sealing ring on its the respective sealing seat ( 18 . 19 ) facing side has an armor, which extends in particular over any existing sink holes. Shut-off device according to claim 6, characterized in that the armor and / or the sealing ring has / have hardened and / or polished sealing surface (s).  An ethylene production plant having a cracking furnace operable in a production mode and a decoking mode, wherein a first obturator is disposed in a transfer line and a second obturator in a decoking line, which are mutually movable to an open and closed position, the first and / or the second obturator is a slide valve according to one of the preceding claims.

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