Method and plant for producing ethylene and / or other olefins by steam cracking.

Abstract

A process (100) for producing ethylene and / or other olefins by steam cracking, wherein one or more crackers (10) are charged with a paraffin-containing feedstock, and crude gas is recovered from the one or more crackers (10), and the crude gas is at least partially subjected to a process (20) comprising crude gas compression (22) and thermal separation (23) using C2 and C3 refrigerants, wherein a crude gas compressor (CGC) is used for the crude gas compression (22), the ethylene refrigerant is compressed using a C2 refrigerant compressor (ERC), and the propylene refrigerant is compressed using a C3 refrigerant compressor (PRC). In this case, the crude gas compressor (CGC) comprises two successive compressor trains in which the C2 refrigerant compressor (ERC) and the C3 refrigerant compressor (PRC) are each operated at least in part with an electric drive (M) having at least in part identical performance characteristics and provided as structurally identical variable speed drives, each provided via a frequency converter (FU). The invention also relates to a corresponding plant.

Description

Technical Field

[0001] The present invention relates to a method and a plant for producing ethylene and / or other olefins by steam cracking as described in the preambles of the respective independent claims.

Background Art

[0002] Methods and plants for the steam cracking of hydrocarbons are described, for example, in the article "Ethylene" in Ullmann's Encyclopedia of Industrial Chemistry (Non-Patent Document 1), online edition of April 15, 2009, DOI 10.1002 / 14356007.a10_045.pub2. Steam cracking is mainly used to obtain short-chain olefins such as ethylene and propylene, diolefins such as butadiene, or aromatic compounds, but is not limited to obtaining such compounds.

[0003] In steam cracking, a component mixture (also called cracked gas or raw gas) is obtained, which is subjected to a treatment sequence suitable for obtaining the individual components of interest. Typically, in the first part (front end) of the treatment sequence, heavy compounds are removed if present, and then so-called raw gas compression, acid gas removal, and drying are carried out. Following the treatment at the front end, rectification is carried out, where fractions are formed in a thermal separation step using ethylene or C2 refrigerant and propylene or C4 refrigerant, and are further separated if necessary. For details, reference is made to the aforementioned article "Ethylene" in Ullmann's Encyclopedia of Industrial Chemistry (Non-Patent Document 1), particularly Sections 5.3.2.1, "Front End", and Section 5.3.2.2, "Hydrocarbon Rectification Section".

[0004] In one embodiment of the rectification that can also be used in the case of the present invention, the rectification first involves separating hydrocarbons having three and more carbon atoms and higher boiling compounds from hydrocarbons having two and fewer carbon atoms and lower boiling components such as methane and hydrogen. Such a step is usually also called de-ethanization, and the configuration of the rectification is called the "first de-ethanizer" method or the "front-end de-ethanizer" method.

[0005] The fraction of hydrocarbons having two carbon atoms and a lower boiling point component, obtained in gaseous form by deethane, is offered for further separation, where the hydrocarbons having two carbon atoms are separated from the lower boiling point component contained together. Such a step is also called demethanization. In the "deethane column 1" method or "front-end deethane column" method, demethanization is therefore downstream of deethane.

[0006] Alternatively, the deethane and demethane steps can be carried out in reverse order. This is therefore called the "Ethane Column 1" method or the "Front End Demethane Column" method. Further alternative methods are described in the aforementioned technical literature.

[0007] As part of the processing sequence, compressors are used at various positions. In particular, crude gas compression is carried out using a decomposition gas compressor (CGC), and so-called ethylene refrigerant compressors (ERCs) and so-called propylene refrigerant compressors (ERCs) are used when ethylene or C2 refrigerant and propylene or C3 refrigerant are supplied. These terms will be used hereafter, but in some cases ethane may also be compressed in an ethylene refrigerant compressor, and in some cases propane in a propylene refrigerant compressor. The product fraction of the thermal separation may be subjected to compression using a further compressor called a product compressor.

[0008] European Patent Application Publication No. 3730592 (Patent Document 1) describes an olefin synthesis plant. It includes a feed pretreatment section configured to pretreatment a feed stream, and a pyrolysis section including one or more pyrolysis reactors configured to decompose hydrocarbons in an input stream in the presence of a diluent for generating a decomposition gas stream. A primary rectification and compression section is provided, configured to recover heat from the decomposition gas stream to quench the decomposition gas stream, remove certain components from the decomposition gas stream, and compress the decomposition gas stream, thereby obtaining a compressible decomposition gas stream. Alternatively or in addition, a product separation section may be provided, configured to separate a product olefin stream from the compressible decomposition gas stream. This olefin synthesis plant is configured such that, compared to conventional olefin synthesis plants, a larger portion of the energy and / or net energy required by the olefin synthesis plant and / or one or more of its parts is obtained from non-carbon and / or renewable energy sources and / or electricity.

[0009] The object of the present invention is to improve the method and plant, and in particular to configure them to be adaptable to different energy ranges at the plant site. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] European Patent Application Publication No. 3730592 [Non-patent literature]

[0011] [Non-Patent Document 1] Ullman's Encyclopedia of Industrial Chemistry, online edition April 15, 2009, DOI 10.1002 / 14356007.a10_045.pub2 [Overview of the project]

[0012] This objective is achieved by methods and plants for producing ethylene and / or other olefins by steam cracking, each having the characteristics of an independent claim. Each embodiment is the subject of the dependent claims and the following description.

[0013] In general, the present invention proposes a method for producing ethylene and / or other olefins by steam cracking, wherein one or more cracking units, i.e., cracking furnaces, which can be embodied in a conventional manner with convection and radiant zones, are filled with paraffin-containing feedstock such as naphtha or ethane or mixtures thereof or any other feedstock known or convenient in the art, and wherein crude gas is recovered from one or more cracking units, and this crude gas is subjected to processing including crude gas compression and thermal separation, at least in part, using ethane and / or ethylene refrigerants (C2 refrigerants) and propane and / or propylene refrigerants (C3 refrigerants). The refrigerants mentioned can be used, in particular, to condense the gas mixture, to boil the sump evaporator of the separation column, or in the corresponding head cooler.

[0014] Where “ethane and / or ethylene refrigerants,” “C2 refrigerants,” “propane and / or propylene refrigerants,” or “C3 refrigerants” are referred to herein, they may be the corresponding pure substances or mixtures of the referred components. In each case, the other components may also be present, typically in small amounts of less than 10%.

[0015] A crude gas compressor is used to compress a crude gas within the scope of the present invention, C2 refrigerant is compressed using a C2 refrigerant compressor, and C3 refrigerant is compressed using a C3 refrigerant compressor. Explicit references to the prior art mentioned at the beginning are made for further details of the method, which will be illustrated hereafter. As stated above, C2 refrigerant compressors and C3 refrigerant compressors are also abbreviated as C2 refrigerant compressors (ERC) and C3 refrigerant compressors (PRC), respectively.

[0016] In this invention, the crude gas compressor has two continuous compressor trains, and each of these compressor trains, the C2 refrigerant compressor and the C3 refrigerant compressor, is operated, in each case, at least partially using an electric drive. To avoid misunderstanding, the statement that a particular compressor or compressor train is driven “each” with an electric drive means that one compressor train is driven by a first electric drive, the other compressor train is driven by a second electric drive, the C2 refrigerant compressor is driven by a third electric drive, and the C3 refrigerant compressor is driven by a fourth electric drive. In this invention, one compressor train of a crude gas compressor, in particular the upstream compressor train, includes two compressor stages, and the other compressor train includes three compressor stages. More generally, a compressor train includes a particularly different number of compressor stages. As can be seen from the present invention, the operating modes proposed by the present invention offer special advantages over known drive systems of the prior art, for example, by using a condensing steam turbine in accordance with API 612, etc. The following description of conventional operating modes is not intended to limit the present invention in any way, but in such conventional operating modes, for example, a decomposition unit using waste heat is provided, which has ultra-high pressure steam (HHP steam), i.e., steam at a pressure level of 90-130 bar and a temperature level of 450-540°C, and is used to drive a crude gas compressor. The ultra-high pressure steam is usually expanded through the high-pressure section of the drive turbine of the crude gas compressor. A considerable portion of the steam is then extracted as high-pressure steam (HP steam), i.e., steam at a pressure level of 35-50 bar and a temperature level of 250-400°C, and supplied to the drive turbines of the C2 refrigerant compressor and the C3 refrigerant compressor. Depending on the requirements of further consumption devices, medium-pressure steam (MP steam) or low-pressure steam (LP steam), i.e., steam at a pressure level of 15-25 bar and a temperature level of 200-250°C, or steam at a pressure level of 3-8 bar and a temperature level of 150-190°C, can also be produced.To improve the overall energy balance, additional steam may be introduced from a high-pressure steam generator or from an external source. In this case, steam for balance adjustment is also provided via the plant boundary zone.

[0017] The conventional energy balancing methods described above must be carried out while taking into account the constraints arising from the power demands of three major consuming devices: the crude gas compressor, the C2 refrigerant compressor, and the C3 refrigerant compressor. This typically requires the introduction of high-pressure steam generators, including corresponding steam boilers, to disconnect the ultra-high-pressure and high-pressure steam demands for energy balancing. This increases structural complexity. In addition, the heat of condensation of the steam is left largely unused, while instead, the waste steam from the turbine is usually condensed by cooling water, which is a high expense from the perspective of the equipment. Ultra-high-pressure and high-pressure steam generators involve significant carbon dioxide emissions; the incorporation of alternative (carbon-neutral, if necessary) energy sources to drive the compressors is usually not provided or possible.

[0018] The use of the present invention results in greater flexibility in ethylene production or other olefin production with respect to steam and carbon dioxide balance adjustment, due to the extremely high degree of independence between compressor operations arising from the use of an electric drive. In particular, the robust connection between the use of high-pressure steam in crude gas compression and the subsequent use of high-pressure steam in refrigerant compression is no longer an obstacle to flexibility in the case of the present invention. [Brief explanation of the drawing]

[0019] [Figure 1] The method according to the embodiment of the present invention is shown in the form of a simplified process diagram, with the whole represented by 100. [Figure 2] The arrangement 200 according to an embodiment of the present invention is shown. [Figure 3] A further embodiment of the present invention, arrangement 300, is shown. [Modes for carrying out the invention]

[0020] In a particularly preferred embodiment of the present invention, the super-high-pressure steam is still supplied using waste heat from one or more decomposition apparatuses. However, this is advantageously at least partially removed from the plant and / or at least partially used as a heat source for other process steps without being used to drive the raw gas compressor, the C2 refrigerant compressor, and the C3 refrigerant compressor.

[0021] In a particularly preferred embodiment of the present invention, or as an alternative to the means proposed by the present invention, for the above-mentioned removal and / or intended use, the super-high-pressure steam can be adapted in a conditioning unit, a so-called pressure reduction station, in terms of pressure and / or temperature. In the conditioning unit, in particular, all the generated condensation heat can be used for other purposes, for example, for supply to a district heating network.

[0022] In a particularly preferred embodiment, the method used according to the present invention can be implemented without using a high-pressure steam boiler. In other words, the use of the present invention makes it possible to omit the high-pressure steam boiler, thereby reducing the demand for fossil energy carriers and thus improving the carbon dioxide balance. In principle, in the case of the present invention, it is possible to incorporate carbon-neutral energy at any time, resulting in a significant flexibility with regard to carbon dioxide emissions. As described above, the raw gas compressor according to the present invention includes two consecutive compressor trains, i.e., structurally independent units that can be individually driven, and each compressor train of the raw gas compressor, the C2 refrigerant compressor, and the C3 refrigerant compressor is operated by an electric drive device having at least partially the same performance characteristics. Advantageously, the drive devices can also be substantially identical in structure. Thus, the number of common parts increases, and the creation of the plant is significantly improved within the scope of the significance of the standardization concept.

[0023] Electric drive units having at least partially identical performance characteristics are provided as structurally identical variable speed drive units, each of which is provided via a frequency converter. Each of the respective continuous compressor trains for crude gas compression, C2 refrigerant compressors and refrigerant compressors are matched to one another from the perspective of their torque. In this way, corresponding standardization can be achieved that is simultaneously flexible in terms of rotational speed. In particular, four frequency converters can be provided here, and two or all four of them can be used to provide an electric drive unit at any point during the operation of the plant. For reasons of redundancy, in particular, a fifth frequency converter can be kept ready for use, especially for the necessary maintenance and / or repair work.

[0024] The use of the present invention makes it possible to use structurally identical devices, particularly drive units, as spare units, and in particular simplifies the storage of the (common) parts necessary for these devices and maintenance. The present invention is based on the knowledge that the use of structurally identical drive units is also possible and is advantageous despite the associated difficulties and related concerns among technicians. Thus, the present invention particularly achieves improvements in the creation and operation of the plant, and the means proposed by the present invention or embodiments thereof are not obvious from the prior art.

[0025] The crude gas compressors, ethylene and propylene compressors exhibit significant performance differences, so the matching of the performance of the drive units is not self-evident. Furthermore, the performance ratio of the ethylene compressor and the propylene compressor varies particularly depending on the feed raw materials and process implementation (in particular, the separation of heavier hydrocarbons having 5 or more carbon atoms). The crude gas compressor usually includes five stages, which would seem difficult to divide. The high pressure conditions of the individual stages can lead to high temperatures and thus to the risk of seizure, so the pressure conditions of the crude gas compressor can only be changed to a limited extent. Without the knowledge of the embodiments of the present invention, a person skilled in the art would stop considering such a solution.

[0026] In embodiments of the present invention, the crude gas compressor can be divided into two and three stages in the manner described above. Furthermore, changes to the pressure conditions within a given limit, and especially the use of external cooling, as provided by embodiments of the present invention, are possible. This, in turn, leads to a desirable load on the propylene compressor used, and therefore to matching of the propylene and ethylene compressors.

[0027] The use of structurally identical variable-speed drive devices would also not be apparent without knowledge of the present invention or its corresponding embodiments. This is because not only the output but also the torque needs to be matched. This means that the compressors must rotate at similar speeds or use a gear mechanism (for speed and torque conversion). Without torque matching, motors cannot be standardized, even with the same output. Therefore, in the case of the present invention, one or more gear mechanisms are used in particular.

[0028] The advantages of the embodiments of the present invention lies in the use of additional frequency converters, particularly in the provision of redundancy n+1. In other embodiments of the present invention, this can also be achieved with different frequency converters and / or drivers, in which case corresponding adjustments in terms of efficiency, spare parts inventory, and dimensions would be accepted. The additional frequency converter here needs to correspond to the largest of the four frequency converters used regularly, and without load matching, this would inevitably be greater than the average output when the four drivers are identical.

[0029] The four frequency converters can be deployed as pairs with full redundancy (2x100%), and the two frequency converters in each pair can operate simultaneously in partial load mode (2x50%) or in switching mode (alternating) at full load (1x100% in each case). In the case of two independent supply networks, the frequency converters can conveniently be coupled to both networks. This redundancy concept is particularly suitable when voltage drops / failures in the supply networks are anticipated and switching time should be minimized to enhance plant availability.

[0030] For powerful drive systems that exceed the performance limits of frequency converters, a 3x50% redundancy concept can be considered. In this case, two frequency converters operating simultaneously would supply 100% of the total output.

[0031] In one embodiment of the method according to the present invention, four frequency converters and a fifth frequency converter are provided as part of a frequency converter arrangement, the frequency converter arrangement of the fifth frequency converter is kept operational, in particular a hot standby state, i.e., at least partially voltage-applied, during execution of the method, as described below.

[0032] In one embodiment, each frequency converter arrangement includes an input transformer, particularly a VSD transformer, and inputs and outputs, the inputs and outputs (particularly the inputs via the input transformer) being connected to a current source and their respective drivers by a switching device. Selective activation of the switching device at the outputs allows each frequency converter to be selectively connected to a specific, rather than arbitrary, driver.

[0033] The mean time between failures (MTBF) or mean time to repair (MTTR) for variable-speed electric drive systems under current standards is approximately 10 years. However, since all three compressors (CGC, ERC, and PRC) are required simultaneously for plant operation, availability is reduced (e.g., using a reliability block diagram), making it difficult to achieve the industry standard of 5 years of uninterrupted plant operation. However, standardization of the drive system allows for the introduction of key spare parts, which may be needed at some point anyway, in a "cold standby" or "hot standby" state. Therefore, in the event of a failure, it is advantageous to be able to switch between the corresponding devices with (significant) delay. As a result, the MTBF or MTTR can be extended, for example, up to 20 years in the case of this invention.

[0034] In the embodiments of the present invention described, a fifth frequency converter, conveniently including peripheral equipment (cooling device, transformer, switching device), is introduced in a state ready for immediate use and interconnection so that it can be used as redundancy for each of the four existing frequency converters. For switching, a temporary shutdown or stop of the equipment can be taken into consideration ("cold standby"). Alternatively, the switching can be performed during operation, in which case the interruption of drive torque can be minimized. Switching times of less than 500 ms are technically possible and desirable; from a control technology standpoint, the switching sequence can be connected to the compressor's pump protection control (feedforward signal to surge protection control device) as needed.

[0035] In embodiments of the present invention, the corresponding transformers and frequency converters are, in particular, so-called "major spare parts," meaning they are already provided during the introduction of the plant and are continuously kept ready during operation. They are therefore included in the investment cost.

[0036] If, as provided in some embodiments of the present invention, these spare parts are not in a warehouse but are instead provided as "installed" spare parts, they can be made usable in a very short time, for example, within 500 ms as described above.

[0037] Another particular advantage of the present invention is that, since a power storage device requiring a table base is not required, the crude gas compressor, C2 refrigerant compressor, and C3 refrigerant compressor can be installed on the ground surface.

[0038] Conveniently, intercooling can be performed at least temporarily in the crude gas compressor using external cooling, for example, by using propane or propylene cold air (C3 cooling). In principle, this intercooling can be performed before each stage. Pre-cooling of the fourth stage is particularly preferable because, as a result, the same performance of the first to third stages and the fourth and fifth stages are achieved, on the one hand, and unacceptably high outlet temperatures are avoided. In this situation, a different distribution of compressor stages to the drive unit can be provided than that described in the example above. This is particularly advantageous within the scope of the significance of the standardization described. In the present invention, external cooling for intercooling can be provided using at least a portion of the C2 refrigerant and / or C3 refrigerant, with the corresponding refrigerants combined from their respective refrigerant circuits.

[0039] In some embodiments of the present invention, the above-described intercooling can be carried out continuously or with external cooling only when the cooling water temperature and / or water injection is deemed insufficient and / or not functioning. This allows for optimization of operating costs.

[0040] In the present invention, in order to make the output requirements as uniform as possible, it is assumed in a particularly preferred embodiment that the drive output of the electric drive units for the crude gas compressor, C2 refrigerant compressor and C3 refrigerant compressor is adjusted by varying the cooling output between the C2 refrigerant circuit, in which C2 refrigerant is used, and / or by incorporating C3 cooling as additional intermediate cooling for the crude gas compressor, as described above.

[0041] The present invention also extends to a plant for the production of ethylene and / or other olefins by steam decomposition, having one or more decomposition units configured to fill a paraffin-containing feedstock and obtain crude gas, wherein the plant is configured to subject the crude gas to a process including at least partially crude gas compression and thermal separation using C2 and C3 refrigerants, wherein a crude gas compressor is provided for crude gas compression, a C2 refrigerant compressor is provided for compressing the C2 refrigerant, and a C3 refrigerant compressor is provided for compressing the C3 refrigerant. With respect to features of the present invention, references are made to the corresponding independent claims.

[0042] References to the features and advantages of corresponding plants and their advantageous embodiments are explicitly made to the above description of the method proposed by the present invention and its embodiments, for this is because they apply equally to the corresponding plants and their embodiments. This is especially true in plants designed to carry out the method, as described above in another embodiment.

[0043] The present invention will be described in more detail below with reference to the accompanying drawings illustrating embodiments of the invention.

[0044] Figure 1 shows a simplified process diagram illustrating a method according to an embodiment of the present invention, with the entire process represented by 100. The following description relates to the method and corresponding method steps, but they also apply to the corresponding plant and its components. In method 100, one or more decomposition devices (decomposition furnaces) 10 are used, which are filled with supply raw materials A (as well as steam, not shown separately here), and from which crude gas B is recovered. Crude gas B is subjected at least in part to a process indicated here as 20 as a whole, which includes a quenching step 21 and a compression (crude gas compression) step 22 and a thermal separation step 23 using C2 and C3 refrigerants, with the separation of pyrolysis oil C by a method known in itself. In the quenching step 21, vapor D is provided and can be recycled into one or more cracking units 10. In the compression step 22, pyrolysis gasoline E can be separated and can be recycled, for example, into the quenching step 21. In the quenching step 21, hydrocarbons F having three or more carbon atoms can be further separated and transferred to the corresponding processing step 24, where the corresponding hydrocarbons G are also supplied from the thermal separation step 23. In the thermal separation step 23, an ethane stream H can be provided and can be recycled into one or more cracking furnaces 10. Ethylene stream I can be realized as a product. In particular, so-called tail gas K, containing methane and hydrogen, is discharged. A further product stream, represented as L as a whole, is provided in a further processing step 24. As indicated by the symbols in the lower region of Figure 1, the compressor represented by CGC is used for the crude gas compression step 22, the ethylene refrigerant is compressed using the C2 refrigerant compressor represented by ERC, and the propylene refrigerant is compressed using the C3 refrigerant compressor represented by PRC. The crude gas compressor CGC, the C2 refrigerant compressor ERC, and the C3 refrigerant compressor PRC are each operated at least partially by one or more electric drive units M. More precisely, in the embodiments of the present invention shown herein, the crude gas compressor CGC comprises two continuous compressor trains (not shown separately), and each of the compressor trains of the crude gas compressor CGC, refrigerant compressor ERC, and C3 refrigerant compressor PRC is operated by an electric drive having at least partially identical performance characteristics in each case. The electric drive can be provided herein as structurally identical variable speed drive units, each provided via a frequency converter FU. Overall, in the example shown herein, five frequency converter FUs are provided, two of which (forming pairs for alternating full-load operation) or four (forming pairs for partial-load operation) are used to provide an electric drive M at any time, and one is kept ready for immediate use for reasons of redundancy. In the example shown herein, the frequency converter FUs are connected to different networks or power sources N1, N2 in the manner shown. The present invention is not limited to the example shown herein. The steam D or other steam provided by this method includes, in particular, ultra-high pressure steam, which is at least partially discharged and / or used as a heat source for other method steps without being used to drive the crude gas compressor RGC, the C2 refrigerant compressor ERC and the C3 refrigerant compressor PRC. In terms of pressure and / or temperature for discharge and / or intended use, the ultra-high pressure steam can be adapted to the adapted unit generally shown here in 50. The heat of condensation accumulated in the adapted unit 50 can be used as described. All embodiments of the present invention that can be similarly used in Method 100 shown in Figure 1 are explicitly referenced again in the above description.

[0045] Figure 2 shows arrangement 200 according to an embodiment of the present invention. In each case, since multiple preferably identical components are shown, the corresponding reference numerals are shown only once. The input transformers (in particular, VSD transformers) are connected to the busbar 1 via switching device 2, and each input transformer is embodied here by a frequency converter, represented as 4, in particular in the intermediate circuit (VSI), as an indirect converter with a DC voltage. Each drive unit is again connected via switching device 5. The group of switching devices 2a and 5a and input transformers 3a and frequency converters 4a shown on the left side of the figure can be selectively connected to one of the drive units M using one of the switching devices 6 if the drive unit M is disconnected from the frequency converter to which it was originally connected via the corresponding switching device 5. Switching device 2a may remain closed during operation, so that the input transformers 3a and frequency converters 4a can maintain a "hot standby" state.

[0046] Figure 3 shows arrangement 300 according to a further embodiment of the present invention. Here again, since multiple preferably identical components are shown in each case, the corresponding reference numerals are given only once. In contrast to the arrangement 200 shown in Figure 2, the arrangement 300 shown in Figure 3 presents a different redundancy concept, in which each drive unit M can, as an alternative, be connected to one of two trains of switching devices 2 and 5, input transformer 3 and frequency converter 4 (or 2a, 5a, 3a, and 4a, indicated only on the left drive unit M).

Claims

1. A method (100) for producing ethylene and / or other olefins by steam decomposition, wherein one or more decomposition units (10) are filled with paraffin-containing feedstock, crude gas is recovered from one or more decomposition units (10), the crude gas is at least partially subjected to a process (20) including crude gas compression (22) and thermal separation (23) using C2 and C3 refrigerants, a crude gas compressor (CGC) is used for the crude gas compression (22), the C2 refrigerant is compressed using a C2 refrigerant compressor (ERC), and the C3 refrigerant is compressed using a C3 refrigerant compressor (PRC), and the crude gas compressor (CGC) is comprised of two continuous compressors A method comprising a train, wherein in each of these compressor trains, the C2 refrigerant compressor (ERC) and the C3 refrigerant compressor (PRC) are each operated at least partially using an electric drive (M), the electric drive (M) having at least partially identical performance characteristics, each being powered via a frequency converter (FU), each being provided as a structurally identical variable speed drive, and the continuous compressor train of the crude gas compression (22), the C2 refrigerant compressor (ERC) and the C3 refrigerant compressor (PRC) are each matched with respect to their torques.

2. The method according to claim 1, wherein waste heat is used to provide ultra-high pressure steam, which is at least partially removed and / or used as a heat source for other method steps, without being used to drive the crude gas compressor (CGC), the C2 refrigerant compressor (ERC), and the C3 refrigerant compressor (PRC).

3. The method according to claim 2, wherein the ultra-high pressure steam is adapted with respect to pressure and / or temperature in a suitable unit (50) for discharge and / or use.

4. The method according to claim 3, wherein the heat of condensation obtained in the adaptable unit (50) is used.

5. The method according to any one of claims 1 to 4, which is operated without using a high-pressure steam boiler.

6. The method according to any one of claims 1 to 5, wherein four frequency converters (FUs) are provided, two or four of which are used to provide an electric drive at any time, and in particular a fifth frequency converter is kept ready for immediate use for reasons of redundancy.

7. The method according to claim 6, wherein the four frequency converters (FUs) and the fifth frequency converter (FU) are each provided as part of a frequency converter arrangement, and the fifth frequency converter (FU) having the frequency converter arrangement is kept operational during the execution of the method.

8. The method according to claim 7, wherein each of the frequency converter arrangements comprises an input transformer and inputs and outputs, and the inputs and outputs are connected to a current source and the respective drive devices via a switching device.

9. The method according to any one of claims 1 to 8, wherein the crude gas compressor (CGC), the C2 refrigerant compressor (ERC), and the C3 refrigerant compressor (PRC) are installed on the ground surface.

10. The method according to any one of claims 1 to 9, wherein the intercooling is performed at least temporarily in the crude gas compressor using external cooling.

11. The method according to claim 10, wherein the external cooling is provided for the intermediate cooling using at least a portion of the C2 refrigerant and / or the C3 refrigerant.

12. The method according to claim 10 or 11, wherein the intermediate cooling is performed using external cooling when the cooling water temperature and / or water injection is deemed insufficient and / or not functioning.

13. The method according to any one of claims 1 to 12, wherein the drive output of the electric drive units for the crude gas compressor (CGC), the C2 refrigerant compressor (ERC), and the C3 refrigerant compressor (PRC) is adjusted by changing the cooling output between an ethylene refrigerant circuit using ethylene refrigerant and a propylene refrigerant circuit using propylene refrigerant, and / or by incorporating propylene cooling as additional intermediate cooling for the crude gas compressor (CGC).

14. A plant configured to produce ethylene and / or other olefins by steam decomposition, having one or more decomposition units (10) filled with paraffin-containing feedstock and configured to produce crude gas, wherein the plant is configured to at least partially subject the crude gas to a process (20) including compression (22) and thermal separation (23) using C2 and C3 refrigerants, wherein a crude gas compressor (CGC) is provided for the compression (22) of the crude gas, a C2 refrigerant compressor (ERC) is provided for C2 refrigerant compression, and a C3 refrigerant compressor (PRC) is provided for C3 refrigerant compression, and the crude gas compressor (CGC) is provided for two continuous compressors A plant comprising, and in each case, providing at least a portion of the drive output of the two continuous compressor trains of the crude gas compressor (CGC), the C2 refrigerant compressor (ERC), and the C3 refrigerant compressor (PRC), each having at least partially identical performance characteristics, and each provided via a frequency converter (FU), and each provided as a structurally identical variable speed drive unit, wherein each of the continuous compressor trains of the crude gas compression (22), the C2 refrigerant compressor (ERC), and the C3 refrigerant compressor (PRC) is matched with respect to their torques.

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