DE102020121530A1 - Multiple slide system and process plant - Google Patents

Abstract

The present invention relates to a multiple slide valve system for a process plant, in particular an ethylene plant, with a number of process slide valves (15, 15', 17) for opening and closing lines of the process plant and actuators for actuating the process slide valves, with the movement of at least one first and second process slide valve being dependent can be controlled or regulated by at least one process variable by a control or regulating device, the actuating drive of the first and/or the second process slide valve comprising an electric motor with a variable and controllable speed. Furthermore, the invention relates to a process plant.

Description

The invention relates to a multiple slide system for a process plant according to the preamble of claim 1 and a process plant with such a multiple slide system. Such a multi-slider system is, for example, from DE 10 2012 104 216 A1 famous.

Multiple spool systems for process plants are known, in which two spool valves are coupled to one another in order to meet safety requirements within the framework of process management. at DE 10 2012 104 216 A1 this coupling is carried out by an electrical control system (e-linkage) in order to achieve the process control required for safety reasons during decoking of the product line (transfer line) in ethylene production and to adjust the pressure conditions in such a way that safe operation of the process plant is possible. The control required for this is in DE 10 2012 104 216 A1 described. For the actuators used to drive the two slide valves, electric motors with constant speeds are used, which determine the stroke or the closing behavior of the slide valves. Specifically, the desired lift positions of the spool valves are set by repeatedly stopping and restarting the electric motors. The resulting short strokes of the slide valves are sometimes carried out at high frequency until the desired end position is reached. As a result, all moving and mechanically stressed components of the slide mechanism are heavily stressed and are subject to increased wear. In addition, the closing behavior of the slide valves is limited, for example with regard to the closing speed.

The invention is based on the object of specifying a multi-slide system for a process plant that has a number of process slides that interact to comply with safety specifications of the process plant, the multi-slide system being improved with regard to the service life of the process slides and the flexibility of the process control. The invention is also based on the object of specifying a process plant with such a multiple slide system.

According to the invention, this object is achieved by the subject matter of claim 1 with regard to the multiple slide system and by the subject matter of claim 3 with regard to the process plant.

Specifically, the task is solved by a multiple slide valve system for a process plant, in particular an ethylene plant, which has a number of process slide valves for opening and closing lines of the process plant and actuators for actuating the process slide valves. The movement of at least one first and second process slide can be controlled or regulated as a function of at least one process variable by a control or regulating device. The invention is characterized in that the actuator of the first and/or the second process slide includes an electric motor with a variable and controllable speed.

The invention has the advantage that the shocks that occur in the prior art due to the repeated stops and restarts of the electric motors are avoided. This reduces the wear on the moving, mechanically stressed components, so that the maintenance cycles can be extended. Another advantage of the electric motor with variable and controllable speed is the increased flexibility in process control, because the closing and opening behavior of the process slides can be better adapted to the respective operating conditions by setting the optimal closing or opening speed.

The invention is not restricted to plants for the production of ethylene, but can generally be used in chemical or petrochemical process plants in which at least two process slide valves are combined with one another in order to achieve coordinated closing and opening behavior of the two process slide valves. It is conceivable that only one of the two actuators has an electric motor with a variable and controllable speed. The other actuator can be driven by a constant speed electric motor. It is preferred that both the actuator of the first process slide and the actuator of the second process slide each comprise an electric motor with a variable and controllable speed.

The process variable according to which the two process slides are controlled or regulated can be any process variable that is important in the context of process control and must be set. Here, for example, the pressure and/or the temperature of the respective medium of the process plant should be mentioned.

A multiple slide system is understood to mean a system that has two or more process slides. The two process slides work together. It is also possible for more than two process slides to work together.

A preferred embodiment of the invention is specified in dependent claim 2, according to which the first process slide valve is a cracked gas slide valve and the second process slide valve is a decoking slide valve includes. This embodiment is particularly suitable for ethylene production.

In connection with a process plant that has a multiple slide valve system according to the invention, the first process slide valve is arranged in a transfer line and the second process slide valve is arranged in a decoking line, with the transfer line and the decoking line being connected to one another.

The invention will be explained in more detail below with reference to the accompanying drawings. The illustrated embodiments represent examples of how a process plant can be designed with a multi-slide valve system according to the invention.

• 1 eine schematische Darstellung einer Prozessanlage mit einem Mehrfachschiebersystem nach einem erfindungsgemäßen Ausführungsbeispiel;
• 2 einen Detailausschnitt einer Prozessanlage mit einem Mehrfachschiebersystem nach einem weiteren erfindungsgemäßen Ausführungsbeispiel; und
• 3 ein Schaltzeichen eines Stellantriebs eines Prozessschiebers des Mehrfachschiebersystems nach 1 und 2.

In these show

• 1 a schematic representation of a process plant with a multiple slide system according to an embodiment of the invention;
• 2 a detail of a process plant with a multiple slide system according to a further embodiment of the invention; and
• 3 a circuit symbol of an actuator of a process slide of the multiple slide system 1 and 2 .

An embodiment of the invention is based on the 1 explained in more detail. 1 shows a schematic representation of a plant for ethylene production, wherein the two process slides are each equipped with actuators that have electric motors with variable and controllable speed. At this point it is pointed out again that the invention can preferably be used in the production of ethylene since the high safety standards during decoking can be maintained by the invention and at the same time the maintenance cycles can be extended. However, the invention is not limited to this application, but can generally be used in large, safety-critical industrial plants in which multiple slide systems are used.

In the case of the 1 The exemplary embodiment described is a double slide system in which the two process slides are coupled to one another by an electrical control device (electrical linkage or e-linkage). A detailed explanation of the ethylene production process, including the decoking process, is omitted here and paragraphs [0018] to [0024] of those mentioned at the outset DE 10 2012 104 216 A1 referred.

In summary, when decoking the product line, it must be avoided that the pressure in the line section upstream of the process slide valve, which is arranged in the product line, does not drop below a critical value in order to prevent the product or gas from escaping the main product line flows back into the furnace, since ethylene plants connected in parallel convey further via the main product line. In this example, pressure is the process variable that is affected by the process slides. The two process slides are moved depending on the pressure during decoking. Other process variables are alternatively or additionally possible.

The two process slide valves 15, 17 are each arranged in the product line 11 (transfer line) and the decoking line 13, as in FIG 1 shown. The process slides are each equipped with an electric motor 18 with a variable and controlled speed.

In contrast to the process plant according to 1 indicates the process plant according to 2 instead of a double slider system, a triple slider system. As in 2 is shown, the triple slide system comprises three process slides 15, 15', 17, which are also coupled to one another by an electrical control device (electrical linkage or e-linkage). The three process slide valves 15, 15', 17 are arranged in the product line 11 and the decoking line 13. Specifically, a first of the three process slide valves 17 is arranged in the product line 11 . A second and a third of the three process slide valves 15, 15' are arranged in parallel in the decoking line 13. The process slides are each equipped with an electric motor 18 with a variable and controlled speed.

In contrast to the prior art, the electric motors 18 in the ethylene plant according to 1 and 2 equipped with a variable and controllable speed (not shown). For this purpose, the electric motors are connected to corresponding frequency converters or have frequency converters, such as one in 3 is shown.

As a result, the desired end positions of the process slides can be approached quickly and precisely without the impacts on the slide mechanism, which are known in the prior art, occurring. The lifting movement can be slowed down shortly before reaching the end position by reducing the lifting speed, so that the slide mechanism is protected. This reduces the wear on the slide mechanism, so that the maintenance cycles can be extended. Thanks to the electric motors with variable and controllable speeds, the lifting speed of the process slides can also be optimally adapted to the respective operating conditions.

The invention and the exemplary embodiments described above are particularly suitable for controlling double-plate slides, but are not restricted to such slides. Double disc slide as such are known.

The invention or the exemplary embodiments according to the invention described above can also be used in systems in which the media flow is switched from one pipeline to the other. Two or three process slides, for example double plate slides, are used, which are used for shut-off and are driven by speed-controlled electric motors. Such an area of application is, for example, steam crackers. These are also multiple slide systems in which at least two process slides work together.

In connection with such process systems, the invention or the exemplary embodiments according to the invention have the advantage that the process slides can be adjusted at increased speed in non-critical process conditions in order to shorten the changeover time. In critical process conditions, for example when the process pressure is critical, the speed of the process slide can be reduced by the speed-controlled electric motors. This leads to increased safety, since the intervention of the multiple slide system or the slide fitting in the process is slowed down. This gives the operator or the control system more time to react to changes in the process.

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was 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.

Patent Literature Cited

• DE 102012104216 A1 [0001, 0002, 0015]

Claims (3)

Multiple slide valve system for a process plant, in particular an ethylene plant, with a number of process slide valves (15, 15', 17) for opening and closing lines of the process plant and actuators for actuating the process slide valve, the movement of at least one first and second process slide valve depending on at least one process variable a control or regulating device can be controlled or regulated, characterized in that the actuating drive of the first and/or the second process slide comprises an electric motor with variable and regulatable speed. Multiple slider system claim 1 characterized in that the first process slide valve comprises a cracked gas slide valve and the second process slide valve comprises a decoking slide valve. Process plant, in particular ethylene plant, with a multiple valve system claim 1 or 2 , wherein the first process valve is arranged in a transfer line and the second process valve is arranged in a decoking line, the transfer line and the decoking line being connected to one another.

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