Method for manufacturing fuel tanks and an installation for carrying out such a method

Abstract

Method for manufacturing fuel tanks (100), comprising multilayer tanks (101) and singlelayer tanks (102), comprising the following steps: 1) Co-extrusion of a multi-layer material (M1) for at least one multi-layer tank (101) in a co-extrusion plant (Coex), 2) Forming the at least one multi-layered tank (101) from the multi-layered material (M1) in a first forming tool (F1) of the co-extrusion plant (Coex), 3) Providing waste material (A) from the multilayer material (M1) of the co-extrusion plant (Coex) to a mono-extrusion plant for extruding a single-layer material (M2) for at least one single-layer tank (102), wherein the waste material (A) is stored in a collection container (120) in step 3) and is fed to the co-extrusion plant (Coex) and / or the mono-extrusion plant as required.

Description

[0001] The invention relates to a method for manufacturing fuel tanks according to the independent method claim and a system for carrying out a corresponding method according to the independent apparatus claim.

[0002] Fuel tanks, such as gasoline tanks, for vehicles are generally well-known. Gasoline tanks are often made from a multi-layered material, resulting in a multi-layered structure. The production of such fuel tanks generates a relatively large amount of waste material. This waste material can only be reused to a limited extent in the production of similar fuel tanks. Over 50% of the waste material is usually disposed of. Methods for manufacturing fuel tanks are known, for example, from publications DE 696 18 272 T2, DE 10 2004 009 365 A1, and US 5 186 875 A.

[0003] The invention is therefore based on the objective of providing an improved method for manufacturing fuel tanks. In particular, it is the objective of the invention to provide a method for manufacturing fuel tanks that reduces and virtually eliminates the disposal of non-recyclable waste material. Furthermore, it is the objective of the invention to provide a method for manufacturing fuel tanks that enables improved processing and / or reuse of waste material from multi-layer fuel tanks. Finally, it is the objective of the invention to provide a system for manufacturing fuel tanks that is specifically designed to carry out a corresponding method according to the invention.

[0004] The problem according to the invention is solved by an improved method for manufacturing fuel tanks, comprising multi-layer tanks and single-layer tanks, with the features of the independent method claim. Furthermore, the problem according to the invention is solved by a system for manufacturing fuel tanks with the features of the independent apparatus claim. Features described in connection with individual embodiments and aspects of the invention naturally also apply in connection with the other embodiments and aspects of the invention, and vice versa, so that the disclosure relating to the individual embodiments and aspects of the invention always includes, or can include, reciprocal references.

[0005] The invention provides a method for manufacturing fuel tanks, comprising multi-layer tanks and single-layer tanks, comprising the following steps: 1) Co-extrusion of a multi-layer material for at least one multi-layer tank in a co-extrusion plant, 2) Forming the at least one multi-layered tank from the multi-layered material in a first mold of the co-extrusion plant, 3) Providing (at least part of) waste material from the multilayer material of the co-extrusion plant (which, for example, cannot be used within the co-extrusion plant itself) to a mono-extrusion plant for extruding a single-layer material for at least one single-layer tank, wherein the waste material in step 3) is stored in a collection container and fed to the co-extrusion plant and / or the mono-extrusion plant as required.

[0006] Fuel tanks as defined in the invention can hereinafter simply be referred to as tanks.

[0007] The multi-layered tanks according to the invention can advantageously be used for storing hydrocarbon fuels, such as gasoline. Such tanks typically comprise several layers, with at least one of these layers being designed as a barrier layer for the volatile hydrocarbon.

[0008] The single-layer tanks according to the invention can advantageously be used for storing hydrocarbon fuels, such as diesel.

[0009] The waste material, as defined in the invention, is generated by cutting, separating, and / or tearing off the fuel tanks (or, in short, tanks) inside or outside the molds of the co-extrusion plant and the mono-extrusion plant, with or without separate tools (e.g., for deburring), and / or by defective tanks. The molds can be, for example, blow molding tools or blow molding tools.

[0010] The concept of the invention lies in feeding the portion of waste material from the multilayer material of the co-extrusion plant that cannot be processed or reused within the co-extrusion plant itself into the mono-extrusion plant in order to manufacture diesel tanks from co-extrusion regranulate that is up to 100% recyclable. It is conceivable that only small quantities of virgin material can be added to the co-extrusion regranulate in the mono-extrusion plant. In this way, the offcuts from the first die of the co-extrusion plant are completely recycled within the same system (comprising the co-extrusion plant and the mono-extrusion plant) for both multilayer and single-layer tanks. Furthermore, this can reduce the need for virgin material and / or save virgin material.Advantageously, the invention makes it possible to reduce the consumption of petroleum-based plastics used in the manufacture of fuel tanks, thereby improving the CO2 balance in the production of multi-layer and single-layer tanks.

[0011] Thus, the invention provides a method for manufacturing fuel tanks which reduces and almost eliminates the disposal of unusable waste material and enables improved processing and / or reuse of the waste material from multi-layer fuel tanks.

[0012] Furthermore, the invention may provide, in a method for manufacturing fuel tanks, that in step 1) the multilayer material has the following layers: a1) a first polyethylene-containing base layer, which in particular comprises high-density polyethylene, a2) a first adhesion promoter layer comprising in particular polyethylene, preferably a grafted polyethylene, a3) a barrier layer, in particular comprising ethylene-vinyl alcohol copolymer and / or polyamide and / or polyethylene, a4) a second adhesion promoter layer comprising in particular polyethylene, preferably a grafted polyethylene, and / or a5) a second polyethylene-containing base layer, which in particular comprises high-density polyethylene.

[0013] The base layers can preferably serve to provide a stable tank. It is conceivable that the base layers can constitute 90 to 95 percent by weight of the multilayer material. The adhesion promoter layers can also be referred to as binder layers, which preferably serve to ensure adhesion or bonding between the respective base layer and the barrier layer. Furthermore, the adhesion promoter layers can be specifically designed to reduce and preferably prevent shear effects between the respective base layer and the barrier layer. The adhesion promoter layers can also be designed with a substantially temperature-stable viscosity within the associated temperature range of the co-extrusion, particularly between 150°C and 230°C, e.g., between 190°C and 220°C. The adhesion promoter layers can, for example, constitute 1 to 3 percent by weight of the multilayer material. The barrier layer can, for example,The barrier layer can be based on ethylene-vinyl alcohol copolymer or on polyamide. Advantageously, the barrier layer prevents the volatile hydrocarbon from escaping the tank into the environment. The barrier layer can comprise, for example, 1 to 3 percent by weight of the multilayer material.

[0014] Within the scope of the invention, it is further conceivable that the multilayer material can comprise only the layers a1) to a3), wherein, in particular, the barrier layer can be arranged on an inner side of the multilayer tank or exposed to the fuel. Thus, a multilayer material with simplified layer formation and, if necessary, reduced weight can be provided.

[0015] Furthermore, within the scope of the invention, it is conceivable that the multi-layered tank could have a total material thickness of 2 mm to 10 mm, preferably 3 mm to 6 mm. This would allow for a lighter and easier-to-handle tank.

[0016] Furthermore, the invention can provide, in a method for manufacturing fuel tanks, that waste material from the multilayer material of the co-extrusion plant is added to a virgin material of layer a1) and / or a virgin material of layer a5). In other words, waste material can be added to the virgin material of the base layers. This allows for increased reuse of the portion of waste material or the portion of the resulting offcuts of the multilayer material from the first die, directly within the co-extrusion plant.

[0017] Furthermore, the invention may provide, in a method for manufacturing fuel tanks, that at least one further layer is formed between layer a1) and layer a2) and / or between layer a4) and layer a5): a*) a coextrusion regranulate layer, which in particular contains the waste material from the multilayer material of the co-extrusion plant.

[0018] In this way, the waste material can be incorporated or integrated as a separate and / or additional layer within the multi-layered material. This also increases the reuse of the waste material portion or the portion of the resulting offcuts from the first die of the multi-layered material within the co-extrusion plant itself. In particular, it is conceivable that such a co-extruded regranulate layer could be incorporated or integrated between layer a1) and layer a2), as well as between layer a4) and layer a5).

[0019] Furthermore, in a method for manufacturing fuel tanks, the invention may provide that the waste material in step 3) is supplied in the form of co-extrusion regranulate, and / or that the waste material in step 3) is crushed, shredded, cut, torn, granulated, ground, and / or processed by a separate extrusion process. This allows for the reuse of the waste material from the multi-layer material in the extrusion processes. The crushing of the waste material into co-extrusion regranulate can be carried out, for example, using a press and a screen and / or using an additional extrusion screw, which can be, for example, placed upstream of the extrusion screw of the co-extrusion plant.

[0020] Furthermore, in a process for manufacturing fuel tanks, the invention provides that the waste material in step 3) is stored in a collection container (e.g., silo, big bag, container) and fed to the co-extrusion plant and / or the mono-extrusion plant as needed. In this way, the process according to the invention can be carried out flexibly and in a targeted manner. The collection container can, for example, form part of a press for reducing the waste material to co-extrusion regranulate.

[0021] Furthermore, in a method for manufacturing fuel tanks, the invention provides that in step 3) the waste material is returned to the co-extrusion plant via a reprocessing belt, pipelines, a mechanical and / or pneumatic conveying system, and / or transport vehicles, in order to reuse at least part of the waste material in the co-extrusion plant. In this way, a closed conveyor belt process can be created within the co-extrusion plant, allowing for the reuse of the waste material or the resulting offcuts of the multi-layer material.

[0022] Furthermore, in a method for manufacturing fuel tanks, the invention provides that the waste material in step 3) is supplied to the mono-extrusion plant via a conveyor belt, pipelines, a special mechanical and / or pneumatic conveying system, and / or transport vehicles. This mono-extrusion plant connects the co-extrusion plant and the mono-extrusion plant in terms of production technology, in particular to enable a continuous manufacturing process for multi-layer and single-layer tanks. In this way, a common conveyor belt process can be created in the co-extrusion plant and the mono-extrusion plant to supply the multi-layer and single-layer tanks within the shared system. This ensures the reuse of the waste material or the offcuts of the multi-layer material from the first die of the co-extrusion plant in the mono-extrusion plant.

[0023] Furthermore, the invention may provide that a method for manufacturing fuel tanks includes at least one of the following steps: 4) Extruding a single-layer material for at least one single-layer tank in the mono-extrusion plant, at least partly or 100% from the waste material (in the form of the multi-layer material) of the co-extrusion plant, 5) Forming the at least one single-layer tank from the single-layer material in a second mold of the mono-extrusion plant, and / or 6) Reusing waste material from the single-layer material in the mono-extrusion plant to extrude the single-layer material for the at least one single-layer tank.

[0024] In this way, the production of single-layer tanks in the mono-extrusion plant and the reuse of waste material or offcuts from the single-layer material are made possible. The single-layer material can comprise virgin material and / or waste material from the multi-layer material of the co-extrusion plant according to step 3).

[0025] Furthermore, the problem according to the invention is solved by a system for manufacturing fuel tanks, in particular comprising multi-layer tanks and single-layer tanks, comprising: a co-extrusion system for co-extruding a multi-layer material for at least one multi-layer tank and a mono-extrusion system for extruding a single-layer material for at least one single-layer tank, wherein the co-extrusion system and the mono-extrusion system are connected to each other production-related, in particular by a conveyor belt, by pipelines, by a special conveying system (mechanical, pneumatic) and / or by transport vehicles, and are configured to carry out a process which can proceed as described above. The system according to the invention achieves the same advantages that were described above in connection with the process according to the invention. These advantages are fully referenced herein.

[0026] Furthermore, the invention is described in more detail with reference to the figures. It should be noted that the figures are purely descriptive and are not intended to limit the invention in any way.

[0027] They show: Fig. 1 an exemplary representation of a single-layer material and a multi-layer material in accordance with the invention, Fig. 2 an exemplary representation of a co-extrusion plant, and Fig. 3 an exemplary representation of a plant in accordance with the invention, comprising a co-extrusion plant and a mono-extrusion plant.

[0028] The Fig. Figure 1 shows on the left an example of a single-layer material M2, from which single-layer tanks 102, in particular diesel tanks, can be formed using a second forming tool F2 in a mono-extrusion plant Mono. An example of a single-layer tank 102 is described further in the Fig. 3 shown. On the right side of the Fig. Figure 1 shows an exemplary multilayer material M1 from which multilayer tanks 101, in particular gasoline tanks, can be formed using a first forming tool F1 in a co-extrusion plant Coex.

[0029] The multilayer material M1 for the multilayer tanks 101, such as gasoline tanks, can, for example, have 6 layers a1, a2, a3, a4, a5, a*, which will be further discussed below in conjunction with the Fig. 3 will be discussed in detail.

[0030] In the manufacturing of plastic fuel tanks, tanks can be produced using the blow molding process, as is the case with the Fig. Figure 2 shows a schematic representation. The blow molding process is carried out using a co-extrusion plant (Coex). In the Coex co-extrusion plant, a multi-layered material M1 is blow-molded. The multi-layered material M1 is extruded into the form of a tube. The tube is then fed to a first mold F1. Finally, the finished multi-layered tank 101 is formed (specifically blow-molded) in the first mold F1. However, this process generates offcuts, of which up to approximately 50% had to be rejected and disposed of in such blow molding processes, e.g., at a scrap yard (S).

[0031] The invention is implemented using the Fig. 3 explained. The invention provides a method for manufacturing fuel tanks 100 (or simply put, tanks 100), in particular comprising a plurality of multilayer tanks 101 and a plurality of single-layer tanks 102, comprising the following steps: 1) Co-extrusion of a multi-layer material M1 for at least one multi-layer tank 101 in a co-extrusion plant Coex, 2) Forming the at least one multi-layered tank 101 from the multi-layered material M1 in a first forming tool F1 of the co-extrusion plant Coex, 3) Providing (at least part of) a waste material A from the multilayer material M1 of the co-extrusion plant Coex to a mono-extrusion plant Mono for extruding a single-layer material M2 for at least one single-layer tank 102.

[0032] The multi-layered tanks 101 according to the invention can advantageously be used for storing gasoline. The single-layered tanks 102 according to the invention can advantageously be used for storing diesel.

[0033] The waste material A is generated according to the invention by cutting, separating and / or tearing off the fuel tanks 100 in or outside the molds F1, F2 of the co-extrusion plant Coex and the mono-extrusion plant Mono, with or without separate tools (e.g. for deburring), and / or by defective tanks F1, F2. The molds F1, F2 can be designed in the form of blow molding tools or blow molding tools.

[0034] According to the invention, in step 3), the waste material A from the multilayer material M1 of the co-extrusion plant Coex is at least partially or completely supplied to the mono-extrusion plant Mono in order to manufacture diesel tanks from a co-extrusion regranulate that is up to 100% recyclable. It is conceivable that a small amount of virgin material may be added to the co-extrusion regranulate.

[0035] The single-layer material M2 can comprise virgin material and waste material A from the multi-layer material M1 of the co-extrusion plant Coex. This significantly reduces the need for virgin material within the mono-extrusion plant Mono.

[0036] Approximately half of the waste material A can be reused within the Coex co-extrusion plant itself. The other half can be fed into the Mono mono-extrusion plant for the production of single-layer tanks 102.

[0037] However, it is also conceivable that most or all of the waste material A from the co-extrusion plant Coex can be processed in the mono-extrusion plant Mono to produce single-layer tanks 102.

[0038] The offcuts from the first forming tool F1 of the Co-extrusion plant Coex can thus be fully recycled within the joint plant with the Co-extrusion plant Coex for multi-layer tanks 101 and the Mono-extrusion plant for single-layer tanks 102.

[0039] The invention can also enable flexible reuse of the waste material A from the co-extrusion plant Coex in the co-extrusion plant Coex itself and / or in the mono-extrusion plant Mono.

[0040] In the Mono extrusion plant, the waste can be reused by cutting the single-layer tanks 102 in the same Mono extrusion plant, e.g. via a reprocessing belt, through pipelines, through a conveying system (mechanical, pneumatic) and / or through transport vehicles 210.

[0041] Overall, the invention can significantly improve the CO2 balance in the production of multilayer tanks 101 and single-layer tanks 102.

[0042] As mentioned above, and as the Fig. As indicated by 1 on the right, the multilayer material M1 in step 1) can have the following layers: a1) a first polyethylene-containing base layer, which in particular comprises high-density polyethylene, a2) a first adhesion promoter layer comprising in particular polyethylene PE, preferably a grafted polyethylene, a3) a barrier layer, in particular comprising ethylene-vinyl alcohol copolymer EVOH and / or polyamide PA and / or polyethylene PE, a4) a second adhesion promoter layer comprising in particular polyethylene PE, preferably a grafted polyethylene, and / or a5) a second polyethylene-containing base layer, which in particular comprises high-density polyethylene.

[0043] The outer base layer, be it layer a1 or a5, can continue to serve as a decorative layer and be colored accordingly, for example.

[0044] The base layers a1, a5 serve to form a stable tank body and can comprise 90 to 95 percent by weight of the multilayer material M1.

[0045] The adhesion promoter layers a2, a4 can also be referred to as binder layers. These layers serve to ensure adhesion or bonding between the respective base layers a1, a5 and the barrier layer a3. The adhesion promoter layers a2, a4 can also exhibit other properties, such as reducing shear effects between the respective base layers a1, a5 and the barrier layer a3, and / or stabilizing the viscosity within the relevant temperature range of the co-extrusion process, e.g., between 150°C and 230°C, or between 190°C and 220°C. The adhesion promoter layers a2, a4 can, for example, constitute 1 to 2 percent by weight of the multilayer material M1.

[0046] The barrier layer a3 can, for example, be based on ethylene-vinyl alcohol copolymer or on polyamide and serves to reduce the emission of volatile hydrocarbons from the tank into the environment. The barrier layer a3 can comprise, for example, 1 to 3 percent by weight of the multilayer material M1.

[0047] It is also conceivable within the scope of the invention that the multilayer material M1 could only have layers a1 to a3. In this case, it is again conceivable that the barrier layer a3 could be arranged on an inner side of the multilayer tank 101 and could come into contact with the fuel.

[0048] The material thickness of the multi-layered tank 101 and / or the single-layered tank 102 can be, for example, between 2 mm and 10 mm, preferably between 3 mm and 6 mm.

[0049] Within the scope of the invention, it is further conceivable that waste material A from the multilayer material M1 of the co-extrusion plant Coex can be added to a new material of layer a1 and / or a new material of layer a5.

[0050] Furthermore, how the Fig. As indicated in 1, at least one further layer can be formed between layer a1) and layer a2) and / or between layer a4) and layer a5): a*) a coextrusion regranulate layer, which in particular contains the waste material A from the multilayer material M1 of the coextrusion plant Coex.

[0051] The waste material A in step 3) can be provided in the form of co-extrusion regranulate, as described above. For this purpose, the waste material A in step 3) can be heated and, if necessary, crushed, shredded, cut, torn, granulated, ground, and / or processed by a separate extrusion process. The crushing of the waste material A into co-extrusion regranulate can be carried out, for example, using a press with a screen and / or an additional extrusion screw, which can be installed upstream of the extrusion screw of the co-extrusion plant.

[0052] Furthermore, how the Fig. Figure 3 shows that the waste material A in step 3) can be stored in a collection container 120 to be fed to the co-extrusion plant Coex and / or the mono-extrusion plant Mono as needed.

[0053] Furthermore, the Fig. 3, that the waste material A in step 3) can be supplied to the co-extrusion plant Coex via a reprocessing conveyor belt 110, through pipelines, a conveying system (mechanical and / or pneumatic), and / or transport vehicles, which connects the first die F1 at the outlet and the co-extrusion plant Coex at the inlet. In this way, the reuse of the waste material A in the co-extrusion plant Coex can be enabled.

[0054] Furthermore, in a method for manufacturing fuel tanks, the invention can provide that the waste material A in step 3) can be supplied to the mono-extrusion plant Mono on a conveyor belt 200, via pipelines, a special conveying system (mechanical, pneumatic), and / or by transport vehicles. This mono-extrusion plant connects the co-extrusion plant Coex and the mono-extrusion plant Mono in terms of production technology, in particular to enable a continuous manufacturing process for multi-layer tanks 101 and single-layer tanks 102. Thus, the reuse of the waste material A from the co-extrusion plant Coex in the mono-extrusion plant Mono can be ensured.

[0055] Furthermore, a method within the scope of the invention may comprise at least one of the following steps: 4) Extrusion of a single-layer material M2 for at least one single-layer tank 102 in the mono-extrusion plant Mono, at least partly or 100% from the waste material A, in particular in the form of a multi-layer material M1, of the co-extrusion plant Coex, 5) Forming the at least one single-layer tank 102 from the single-layer material M2 in a second mold F2 of the mono-extrusion plant Mono, and / or 6) Reusing waste material from the single-layer material M2 in the mono-extrusion plant Mono for extruding the single-layer material M2 for the at least one single-layer tank 102.

[0056] A corresponding plant 1 for the manufacture of fuel tanks 100, in particular comprising multi-layer tanks 101 and single-layer tanks 102, which are in the Fig.Figure 3, which is specifically designed to carry out a process that can proceed as described above, also represents an aspect of the invention.

[0057] The preceding description of the figures describes the present invention solely by way of examples. Naturally, individual features of the embodiments can be freely combined with one another, provided it is technically feasible, without departing from the scope of the invention. Reference symbol list 1 Annex 100 fuel tank 101 multi-layer tank 102 single-layer tank 110 Reprocessing tape 120 collection containers 200 assembly line 210 Reprocessing tape A waste material F1 first forming tool F2 second forming tool M1 multi-layered material M2 single-layer material a1 first base layer a2 first custody intermediary layer a3 barrier layer a4 second layer of intermediaries a5 second base layer a* Coextrusion regranulate layer Coex co-extrusion plant Mono Mono extrusion plant

Claims

[1] A method for manufacturing fuel tanks (100), comprising multilayer tanks (101) and singlelayer tanks (102), comprising the following steps: 1) Co-extrusion of a multi-layer material (M1) for at least one multi-layer tank (101) in a co-extrusion plant (Coex), 2) Forming the at least one multi-layered tank (101) from the multi-layered material (M1) in a first forming tool (F1) of the co-extrusion plant (Coex), 3) Providing waste material (A) from the multilayer material (M1) of the co-extrusion plant (Coex) to a mono-extrusion plant for extruding a single-layer material (M2) for at least one single-layer tank (102), wherein the waste material (A) is stored in a collection container (120) in step 3) and is fed to the co-extrusion plant (Coex) and / or the mono-extrusion plant as required. [2] Method according to claim 1, characterized by, that in step 1) the multilayer material (M1) has the following layers: a1) a first polyethylene-containing base layer, which in particular comprises high-density polyethylene (PE), a2) a first adhesion promoter layer comprising in particular polyethylene (PE), preferably a grafted polyethylene, a3) a barrier layer, in particular comprising ethylene vinyl alcohol copolymer (EVOH) and / or polyamide (PA) and / or polyethylene (PE), a4) a second adhesion promoter layer comprising in particular polyethylene (PE), preferably a grafted polyethylene, and / or a5) a second polyethylene-containing base layer, which in particular comprises high-density polyethylene (PE). [3] Method according to claim 2, characterized by , that waste material (A) from the multilayer material (M1) of the co-extrusion plant (Coex) is added to a new material of layer a1) and / or a new material of layer a5). [4] Method according to claim 2 or 3, characterized by , that at least one further layer is formed between layer a1) and layer a2) and / or between layer a4) and layer a5): a*) a coextrusion regranulate layer, which in particular includes the waste material (A) from the multilayer material (M1) of the coextrusion plant (Coex). [5] Method according to any one of the preceding claims, characterized by , that the waste material (A) in step 3) is provided in the form of a co-extrusion regranulate, and / or that the waste material (A) in step 3) is crushed, shredded, cut, torn, granulated, ground and / or processed by a separate extrusion process. [6] Method according to any one of the preceding claims, characterized by, that the waste material (A) is provided in step 3) on a reprocessing belt (110), through pipelines, through a mechanical and / or pneumatic conveying system and / or through transport vehicles of the co-extrusion plant (Coex). [7] Method according to any one of the preceding claims, characterized by , that the waste material (A) in step 3) is provided on a conveyor belt (200), through pipelines, through a mechanical and / or pneumatic conveying system and / or transport vehicles of the mono-extrusion plant, which connects the co-extrusion plant (Coex) and the mono-extrusion plant in a production-related manner, in particular to enable a continuous manufacturing process of multi-layer tanks (101) and single-layer tanks (102). [8] Method according to any one of the preceding claims, characterized by that the procedure includes at least one of the following steps: 4) Extruding a single-layer material (M2) for at least one single-layer tank (102) in the mono-extrusion plant, at least partly or 100% from the waste material (A) of the co-extrusion plant (Coex), 5) Forming the at least one single-layer tank (102) from the single-layer material (M2) in a second mold (F2) of the mono-extrusion plant, and / or 6) Reusing waste material from the single-layer material (M2) in the mono-extrusion plant to extrude the single-layer material (M2) for the at least one single-layer tank (102). [9] Plant (1) for manufacturing fuel tanks (100), comprising multilayer tanks (101) and singlelayer tanks (102), comprising: a co-extrusion plant (Coex) for co-extruding a multi-layer material (M1) for at least one multi-layer tank (101) and a mono-extrusion plant for extruding a single-layer material (M2) for at least one single-layer tank (102), wherein the co-extrusion plant (Coex) and the mono-extrusion plant are connected in production technology, in particular by a conveyor belt (200), pipelines, a mechanical and / or pneumatic conveying system and / or transport vehicles, are connected to each other and are configured to carry out a process according to any of the preceding claims.

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