DE102019002220A1 - Process and module set for the creation of a steam cracking system - Google Patents

Abstract

The present invention relates to a method for creating a steam cracking system (100), the steam cracking system (100) having a cracking furnace (10) with a convection zone (11) and a radiation zone (12) and with cracking tubes (122) through the radiation zone (12) guided and connected via one or more transfer lines (14) to one or more quench heat exchangers (15). It is provided that at least part of the radiation zone (12) in the form of one or more furnace modules (II-V) with the cans (122) is prefabricated at a pre-assembly location, with the furnace module or modules (II-V) being transported to a production location and is or will be used at the creation site to create the steam cracking system (100). A corresponding set of modules is also the subject of the invention.

Description

The present invention relates to a method and a set of modules for creating a steam cracking system according to the preambles of the independent claims.

State of the art

Processes and systems for steam cracking have been known for a long time and are extensively described in the specialist literature. In this context, reference is made in particular to the article “Ethylene” in Ullmann's Encyclopedia of Industrial Chemistry, Online Edition, 2007, DOI 10.2002 / 14356007.a10_045.pub2.

Steam cracking systems (often also referred to as ethylene systems) with so-called cracking furnaces are used for steam cracking. These cracking furnaces can also be provided in several groups and operated under different conditions or supplied with different inserts (English feeds). Cracking furnaces typically have a so-called convection zone (English convection section) and a so-called radiation zone (English radiant section). The radiation zone is fired by means of burners arranged at least on the bottom. Flue gases from the radiation zone flow off via the convection zone.

The convection zone is typically used to preheat boiler feed water, to generate or further heat steam and / or to preheat the reaction insert or to further heat a mixture of reaction insert and steam. For this purpose, appropriate tube bundles are passed through the convection zone. The mixture of reaction feed and steam is passed through the radiation zone in so-called cans (coils) for conversion. The cans can be provided in various configurations and arrangements described in the specialist literature.

The so-called cracked gas, which is initially at a temperature of typically 750 to 875 ° C, has to come to a standstill as quickly as possible in order to bring the reactions to a standstill as quickly as possible and thus an excessive formation of To prevent unwanted by-products, are cooled as quickly as possible. So-called quench heat exchangers, which can be subdivided in particular into so-called primary and secondary quench heat exchangers (English. Primary Quench Exchanger, Secondary Quench Exchanger), serve to cool the fission gas. Different designs are also described in the specialist literature.

Depending on its composition, which depends in particular on the reaction inserts and cracking conditions used, the correspondingly cooled cracked gas is subjected to water and / or oil scrubbing, then compression and acid gas removal as well as fractionation operated at least partially at cryogenic temperatures in order to obtain the desired products, traditionally ethylene to be obtained from the cracked gas.

With the previous design and assembly concept of steam cracking systems, the cracking furnaces are delivered to the construction site in many individual parts and assembled accordingly on site. Occasionally, tube bundles for the convection zone are prefabricated and delivered in modular design. Nevertheless, intensive assembly work is required on the respective construction site.

The object of the present invention is to facilitate the construction of steam cracking systems, in particular the cracking furnaces mentioned.

Disclosure of the invention

This object is achieved by a method and a set of modules with the respective features of the independent patent claims. Refinements are the subject matter of the dependent claims and the description below.

The method proposed according to the invention overcomes the problems associated with the previous concept of intensive “on-site” assembly. Such problems are in particular the requirements and regulations that have risen sharply in recent years with regard to compliance with occupational safety and environmental requirements, but also, for example, hindering environmental influences that can even lead to the temporary cessation of assembly activities.

Overall, the known methods involve a great deal of effort in order to permit and administer a construction site for a steam cracking system, with corresponding disruptions and restrictions in the rest of the system operation. The disruptions and restrictions associated with the creation of a steam cracking system are correspondingly longer-term due to the complex and therefore long installation time. In certain regions, there are extremely high assembly costs due to increasing demands on the plant construction sites and the inefficiency of the assembly work.

The new construction concept proposed according to the invention at least partially overcomes these disadvantages and minimizes the installation time and thus also the costs and risks for customers for the construction of steam cracking systems.

With the new design and assembly concept proposed according to the invention for steam cracking systems or the corresponding cracking furnaces, it is possible for the first time, as far as we know, the radiation zone areas of cracking furnaces in addition to the convection zone modules with corresponding furnace modules and prefabricated assembly frames (skids) and large components with minimal assembly effort and reduced assembly time to be delivered to the construction site and installed there.

In the context of the present invention, a cracking furnace is designed so that it is divided into several furnace modules, which are then built accordingly at a prefabrication yard and then delivered to the construction site with suitable means of transport and to the finished furnace in a significantly reduced time can be mounted.

In the method proposed according to the invention, it is particularly characteristic that corresponding furnace modules are already fully equipped with the radiation zone pipe system, piping arranged outside the radiation zone, one or more quench heat exchangers (in particular one or more primary quench heat exchangers, but also possibly one or more secondary quench heat exchangers) and one or more several lines between the radiation zone and the one or more quench heat exchangers (and possibly between primary and secondary quench heat exchangers, if these are also part of the furnace module) including the respective welds are provided.

Particular advantages of the method proposed according to the invention also result from the fact that corresponding pressure-bearing parts can be preassembled and the corresponding pressure tests can be carried out in advance.
In addition, in particularly advantageous refinements of the invention, external insulation, expanded internal floor insulation (refractory lining) or other fireproof insulation, instrumentation and electrical components and, if applicable, their cable connections can be preassembled.

Against this background, the present invention proposes a method for creating a steam cracking system, the steam cracking system, as is basically known and explained above, having a cracking furnace with a convection zone and a radiation zone. In the steam cracking system created according to the invention, cracking tubes are passed through the radiation zone and connected to one or more quench heat exchangers via one or more transfer lines.

As already explained, in the conventional method a corresponding creation of a steam cracking system, and thus also the connection of the transfer lines with the quench heat exchanger or the cans, takes place on the construction site. In contrast to this, the present invention proposes that at least part of the radiation zone in the form of one or more furnace modules with the cans is prefabricated at a pre-assembly location, the furnace module or modules being transported to the respective creation location after the prefabrication and at the creation location for the creation of the Steam cracking system is or will be used.

The advantages of the measures proposed according to the invention have already been partially explained above. The present invention in particular enables extensive standardization of both the furnace design and the creation process of a corresponding steam cracking system. In terms of the system design, the furnace module or modules are already considered as sub-assemblies and tested accordingly non-destructively, which leads to significantly reduced effort on the construction site with regard to the overall acceptance of the system and results in significant time savings. In the context of the present invention, there is also an advantage with regard to the area required for creating the steam cracking system and the storage area required in this context. When using the appropriate furnace modules, the customer has to provide fewer so-called utilities such as electricity and water.

Overall, the on-site furnace construction time can be significantly reduced by using the measures proposed according to the invention. In the context of the present invention, assembly times can be reduced significantly, depending on the type of furnace by approx. 30 to 50%. Steam cracking systems planned and constructed within the scope of a method according to the invention also have clear advantages when converting existing systems (revamps). The construction site situation at the place of use, i.e. the construction site of the steam cracking system, is significantly improved and shortened, among other things with regard to safety and environmental requirements, the installation time and the entire schedule due to lower scaffolding costs, crane times, overheads and the like, the product and installation quality, the dependency of environmental and weather influences, the use of administration and monitoring staff by the Plant operator and the disruptive influences on ongoing plant operation. The present invention leads overall to a significantly more economical plant construction with corresponding technical advantages with regard to safety and maintainability.

As already explained, the furnace module or modules prefabricated within the scope of the present invention can also be prefabricated with the quench heat exchanger or heat exchangers. This results in a further degree of prefabrication and lower assembly costs for the entire pressure-side components or these components up to a corresponding quench heat exchanger. The prefabrication according to the invention can include only a primary quench heat exchanger as well as a primary and a secondary quench heat exchanger. In turn, more extensive prefabrication results in less effort when creating the system at the place of installation.

For the sake of clarity, it should be noted that the quench heat exchanger (s) can be typical transfer line heat exchangers for steam cracking systems in which several pipelines are routed through a cooling space through which water or steam flows.

As also mentioned, the furnace module or modules can be subjected to one or more function tests at the prefabrication site, wherein the function test or tests can in particular include a pressure test. The furnace module or modules can also be prefabricated with external insulation, internal floor insulation, instrumentation and / or electrical components and / or their connections. In the case of a higher level of prefabrication in the manner explained, further functional testing can in particular also take place at the prefabrication site, so that this can be largely or at least partially dispensed with at the production site.

As already mentioned, several further modules can be prefabricated at the prefabrication site or at another prefabrication site and used at the production site to create the steam cracking system, in particular one or more furnace floor modules, one or more access modules in the form of stairwells and the like, one or more piping support modules, a or several feed line modules, one or more high pressure line modules, in particular for high pressure steam, and / or one or more discharge modules. A corresponding steam cracking system also typically includes a smoke gas discharge system with, if necessary, corresponding smoke gas cleaning. Such modules, too, can optionally be prefabricated according to the invention.

In particular, within the scope of the present invention, the furnace module or modules can be prefabricated on the basis of a dimension and / or weight specification, in particular with regard to the portability of corresponding modules. The design of the furnace modules can be adapted to include to consider existing pipe bridge heights or other road transport restrictions such as bridges, loads, driveways and the like.

By using the assembly concept proposed according to the invention, a novel logistical concept for cracking furnaces or steam cracking systems can be realized at the same time, namely the possibility of transport while using the advantages of the modularized construction concept. This leads to significantly lower deliveries to the construction site with the advantages of correspondingly lower associated costs on the construction site. This represents a decisive advantage over other variants, for example, in which a complete furnace is pre-built and moved to the final installation site. A modularized creation of a steam cracking system according to an embodiment of the invention has the advantage of being easy to transport with common means of transport and over common transport routes.

The set of modules proposed according to the invention for creating a steam cracking system benefits in the same way from the advantages explained above, so that reference can be made to the explanations above in this regard.

The invention is explained in more detail below with reference to the accompanying drawings, which illustrate preferred embodiments of the invention.

Figure list

• 1 illustrates a steam cracking system that can be created according to an embodiment of the invention in a greatly simplified, schematic partial representation.
• 2A and 2 B each illustrate a vapor cracking system that can be created according to an embodiment of the invention with and without corresponding modules in a simplified, schematic partial representation in a front view.
• 3A and 3B each illustrate a vapor cracking system that can be created according to an embodiment of the invention with and without corresponding modules in a simplified, schematic partial representation in side view.

Detailed description of the drawings

In the figures, structurally or functionally corresponding elements are indicated with identical reference symbols and are not explained repeatedly for the sake of clarity.

In 1 a vapor cracking system that can be created according to one embodiment of the invention is illustrated in a greatly simplified, schematic partial representation and as a whole with 100 designated.

In the 1 illustrated steam cracking system 100 comprises one or more cracking furnaces, shown here with a reinforced line 10 . In the following, for the sake of clarity, “a” cracking furnace is used. Typical steam cracking systems 100 include a number of appropriate cracking furnaces 10 that can be operated under the same or different conditions. Appropriate cracking furnaces can also be used 10 have the components explained below in singular or plural form.

The cracking furnace 10 includes a total of here 11 specified convection zone as well as a total here with 12 specified radiation zone. In embodiments, a convection zone can also be provided, for example 11 multiple radiation zones 12 assign.

In the convection zone 11 are several heat exchangers in the example shown 111 to 115 arranged, each also in a different arrangement or order in the convection zone 11 can be provided. These heat exchangers 111 to 115 are typically in the form of convection stones 11 guided tube bundles and are formed by flue gas from the radiation zone 12 flows around.

The radiation zone 12 is in the example shown by means of several burners, which are only partially designated separately here, on the floor and on the wall 121 heated. Heating on the floor only is also possible.

In the example shown, the steam cracking system 100 a gaseous or liquid feed stream containing hydrocarbons 101 fed. Also the use of several feed streams 101 is possible. The feed stream 101 is initially in the heat exchanger 111 preheated.

There is also a boiler feed water flow 102 through the convection zone 11 or the heat exchanger 112 guided and preheated. The boiler feed water flow 102 is then placed in a steam drum 13 fed in. In the heat exchanger 113 in the convection zone 11 becomes a process steam stream 103 who also use the steam drum 13 can be provided, further heated and with the feed stream 101 united.

A collective stream formed in this way 104 The input and steam are converted into another heat exchanger 115 in the convection zone 11 out and then typically in several cans 122 through the radiation zone 12 guided. The representation in 1 is greatly simplified. Typically a corresponding collective flow 104 on a variety of cans 122 divided and after passing through the radiation zone 12 combined as a cracked gas stream again in a common line (not illustrated).

As in 1 further illustrated can be made from the steam drum 13 a stream of steam 105 removed and in another heat exchanger 114 in the convection zone 11 heated, creating a high pressure steam stream 106 can be generated. This can be done in the steam cracking system 100 used in a suitable place.

From the radiation zone 12 or the cans 122 Fission gas is carried out via one or more transfer lines 14th a quench heat exchanger 15th fed and cooled there. The quench heat exchanger 15th represents a primary quench heat exchanger in the example shown. In addition to a primary quench heat exchanger 15th Secondary quench heat exchangers can also be present.

Cooled cracked gas is passed through a line 16 supplied to further process units, which are indicated here only very schematically with 17. With these other process units 17th it can in particular be process units for washing, compressing and fractionating the cracked gas.

The quench heat exchanger 15th is in the example shown with a water flow 106 from the steam drum 13 loaded. One in the quench heat exchanger 15th vapor stream formed in this way 107 gets into the steam drum 13 returned.

An essential aspect of a method used in accordance with an embodiment of the present invention for creating a corresponding steam cracking system 100 consists in at least part of the radiation zone 12 at least with the cans 122 in the form of one or more furnace modules. Other components can also be included accordingly.

A corresponding furnace module, which is available in 1 encompassed by dash-dotted lines and designated as a whole by II, one or more quench heat exchangers can also be used 15th include. The furnace module or modules II are used within the scope of the present invention or a corresponding embodiment for creating the steam cracking system 100 according to 1 is used, prefabricated at a pre-assembly location, transported to a corresponding creation location, and at the creation location for the creation of the steam cracking system 100 used. An essential aspect of the present invention is to equip a corresponding unit with the cans and to subject them to a pressure test at the pre-assembly location, for example.

As illustrated in the following figures, a corresponding steam cracking system 100 in addition to the furnace module II also have further furnace modules III-V, as well as further modularized units that can be prefabricated as a module set at the pre-assembly location or at different pre-assembly locations and then transported to the production location.

In the 2A and 2 B is a vapor cracking system which can also be created according to an embodiment of the present invention in opposite to FIG 1 illustrated in more detail, but also with 100 designated. The 2A shows the steam cracking system 100 without the corresponding modules and the 2 B shows the steam cracking system 100 with these. The modules are represented by rectangles that cover the components they contain.

An oven module that is already in 1 illustrated and shown there in greatly simplified form and designated by II, is also provided here. The steam cracking system according to FIGS 2A and 2 B further furnace modules, here marked III-V. The furnace modules II-V form the entire radiation zone of a cracking furnace of the steam cracking plant 100 of the 2A and 2 B .

As a further module that is used when creating the steam cracking system 100 according to the 2A and 2 B is used, is a furnace base module I, which can in particular comprise an inner floor insulation or burner or preparatory components for attaching burners.

Furthermore, in the 2A and 2 B an access module VI with a lower part of a stairwell, a further access module VII with an upper part of a stairwell, a lower piping support module VIII, an upper piping support module IX, a feed line module X, a high pressure line module Xa and a discharge module XI. The 2A and 2 B show further modules XX, XXI and XXII, which can be used to discharge flue gases or product flows.

In the 3A and 3B is already in the 2A and 2 B illustrated steam cracking system shown again in side view. The explanations to the 2A and 2 B apply in a corresponding manner, with additional modules being illustrated here, but not explained separately. The modules already explained above are also partially illustrated, but partially covered due to the different representation.

Claims (12)

A method for creating a steam cracking system (100), wherein the steam cracking system (100) has a cracking furnace (10) with a convection zone (11) and a radiation zone (12) and wherein the radiation zone (12) is guided through cracking tubes (122) and via one or several transfer lines (14) are connected to one or more quench heat exchangers (15), characterized in that at least part of the radiation zone (12) is prefabricated in the form of one or more furnace modules (II-V) with the cans (122) at a pre-assembly location is, the furnace module or modules (II-V) being transported to a production site and used at the production site to produce the steam cracking system (100). Procedure according to Claim 1 , in which the furnace module or modules (II-V) is also prefabricated with the quench heat exchanger or heat exchangers (15). Procedure according to Claim 2 , in which the furnace module or modules (II-V) is or are prefabricated with several quench heat exchangers (15), the several quench heat exchangers (15) comprising one or more primary quench heat exchangers and one or more secondary quench heat exchangers. Method according to one of the preceding claims, in which the or at least one of the several quench heat exchangers (15) is designed as a heat exchanger in which several pipes (141) are led through a cooling space through which water or steam flows. Method according to one of the preceding claims, in which the furnace module or modules (II-V) is or will be subjected to one or more functional tests at the prefabrication site. Procedure according to Claim 5 wherein the one or more functional tests comprise at least one pressure test. Method according to one of the preceding claims, in which the furnace module or modules is or are also prefabricated with external insulation, internal floor insulation, with instrumentation and / or electrical components and / or their connections. Method according to one of the preceding claims, in which one or more further modules (VI-XI) are also prefabricated at the prefabrication site or at a further prefabrication site. Procedure according to Claim 8 , in which the further module (s) (VI-XI) has one or more furnace base modules (I), access modules (VI, VII), piping support modules (VIII, IX), feed line modules (X), high pressure line modules (Xa) and / or discharge modules (XI ) include. Method according to one of the preceding claims, in which the furnace module or modules (II-V) are prefabricated on the basis of a specified dimension and / or weight. Module set for creating a steam cracking system (100), the steam cracking system (100) having a cracking furnace (10) with a convection zone (11) and a radiation zone (12) and with cracking tubes (122) guided through the radiation zone (12) and over one or several transfer lines (14) are connected to one or more quench heat exchangers (15), characterized in that the module set comprises one or more furnace modules (II-V) with the cans (122), the furnace module or modules (II-V) can be transported to the creation location and can be used at the creation location for creating the steam cracking system (100). Module set according to Claim 11 , one or more further modules (VI-XI), comprising one or more furnace base modules (I), access modules (VI, VII), piping support modules (VIII, IX), feed line modules (X), high pressure line modules (Xa) and / or discharge modules (XI).

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