Mounting arrangement for a cryogenic gas storage device

Abstract

Fastening arrangement (1) for suspending an inner tank (2) of a cryogenic gas storage device (3) on an outer tank wall (4), wherein the fastening arrangement is made of a glass-fibre reinforced plastic from the following components: - a resin from the group of cycloaliphatic epoxy resin systems or from the group of epoxy resin systems with the reaction products bisphenol A-epichlorohydrin resins; - a glass fiber from the group of S2 glass fibers, wherein the fastening arrangement is designed as a tubular arrangement.

Description

[0001] The present invention relates to a fastening arrangement having the features of claim 1 and a cryogenic compressed gas storage device according to the features of claim 7. The present invention therefore relates in particular to a fastening arrangement for suspending an inner tank of a cryogenic gas storage device, wherein the fastening arrangement is formed from a glass fiber reinforced plastic made of a special resin and a glass fiber from the group of S2 glass fibers.

[0002] The automotive industry has been developing alternative and environmentally friendly drive concepts compared to the combustion engine for years. However, the current trend toward the development of hydrogen drives requires safe and practical hydrogen storage. Since hydrogen as a gas can only be stored in a reasonably compact manner under very high pressure, the tanks intended for storage must be designed accordingly. Hydrogen storage systems must therefore be very robust. They are typically designed with safety factors of over 2 with respect to the respective operating pressure and must withstand mechanical impacts, such as those that can occur in a traffic accident, through the use of suitable, high-strength materials.

[0003] Pressure tanks, cryogenic tanks, and cryogenic pressure tanks are used as physical storage devices. Conventional hydrogen storage systems include CGH2 storage tanks, which typically weigh 1 kg - 6 kg and are designed as cylindrical high-pressure tanks and are used up to an operating pressure of approximately 700 bar. CcH2 storage tanks are also worth mentioning. CcH2 refers to cryogenic hydrogen under pressure (cryo-compressed hydrogen), which is why the corresponding tanks are also referred to as cryogenic pressure tanks. The operating pressure of cryogenic pressure tanks is typically 150 bar at 30 K. In a significantly lower pressure range of approximately 2 - 4 bar, LH2 storage tanks, which are also filled with cryogenic hydrogen, are used. The aforementioned tanks also differ from one another in their characteristic and specific properties.For example, it is known that the inner tank suspensions for cryogenic gas storage tanks are made of glass fiber-reinforced plastic, with E-glass being used as the glass fiber. The strength of the inner tank fastening is determined in part by the glass fibers. Glass fibers are a cost-effective yet high-quality material for reinforcing thermosetting resin systems, such as unsaturated polyester resins (UP), epoxy resins (EP), phenolic resins (PF), and polyurethane resins (PUR). Due to their high elongation at break and elastic energy absorption, glass fibers are the most widely used reinforcing fiber for mechanically and thermally stressed fiber composite applications.

[0004] When designing tanks, in addition to safety considerations, weight aspects and heat transfer phenomena from the outer tank shell to the inner tank must also be considered. Undesirable heat transfer occurs, for example, via the inner tank's fastening arrangements to the outer tank. On the other hand, the fastening arrangements must withstand the expected loads. To increase strength, for example, against design-related shear loads, there are considerations for simply increasing the material thickness of the fastening arrangements for suspending the inner tank from the outer tank wall surrounding the inner tank. However, increasing the wall thickness leads to increased heat input into the inner tank, which is undesirable.

[0005] Printed prior art in the present technical field, which reflects the preamble of claim 1, is disclosed in the documents DE 10 2006 043 646 A1 and DE 10 2004 015 295 A1.

[0006] Against this background, it is the object of the present invention to overcome the aforementioned disadvantages and to provide a fastening arrangement with increased strength for suspending the inner tank as well as a cryogenic compressed gas storage device with such a fastening arrangement.

[0007] This object is achieved with a fastening arrangement having the features of claim 1 and a cryogenic compressed gas storage device according to the features of claim 7.

[0008] The basic idea of ​​the present invention is to manufacture the fastening assembly from a defined material composition consisting of an epoxy resin system with a special glass fiber. For the inventive design of the fastening assembly, the glass fiber used is not conventionally used E-glass, but rather an S-glass fiber (S-glass). Particularly preferred is an S2-glass fiber (S2-glass) in combination with an epoxy system, which will be described in more detail later.

[0009] The proposed group of S-glasses or S2-glasses represents a group of specialty glasses with increased mechanical strength compared to E-glass. S-glass closes the gap between conventional E-glass and expensive synthetic high-performance fibers such as carbon, aramid, and Dyneema fibers. Compared to conventional E-glass, S-glass has up to 50% higher strength, up to 20% higher stiffness, and up to 80% higher impact resistance. Surprisingly, it was found that, contrary to theoretical models, an increase in strength transverse to the fiber direction was also observed when the fastening arrangements were formed from the aforementioned inventive material composition. It has been shown that with the use of S2 glass, both the transverse tensile strength and the transverse / longitudinal shear strength increase significantly compared to a conventionally used resin material reinforced with E-glass fibers.An increase in strength (measured absolute increase in N / mm. 2 ) of about 250% - 300% at room temperature and a strength increase of about 80% - 100% at low temperatures of -190°C.

[0010] The high strength of S-glass fiber is based on its inherent strength and the influence of size. Due to the fiber shape, the defect size in the fiber is smaller than in the compact material volume. At the same time, the defect-free length in the fiber shape increases. This makes the strength of S-glass fiber greater than in the compact material. The tensile and compressive strength of S-glass fiber ensures special stiffening of the plastic while simultaneously maintaining a certain flexibility thanks to the high elastic elongation at break (compared to steel). The elastic modulus of S-glass fiber differs only slightly from that of a compact material volume made of glass. Unlike aramid fibers or carbon fibers, glass fiber has an amorphous structure. S-glass fiber therefore has isotropic mechanical properties, which are used here to improve the material properties.The stiffness of a fastening assembly made of S2 glass fiber reinforced plastic is determined by the elastic modulus, the direction and the volume fraction of the glass fibers as well as the properties of the matrix material with the epoxy resin system described below.

[0011] A further aspect of the present invention relates to the resin system used. According to the invention, it is proposed to use a resin from the group of cycloaliphatic epoxy resin systems or from the group of epoxy resin systems with the reaction products bisphenol A-epichlorohydrin resins.

[0012] According to the invention, a fastening arrangement for suspending an inner tank of a cryogenic gas storage device is proposed, wherein the fastening arrangement is made of a glass fiber reinforced plastic, produced from a resin from the group of cycloaliphatic epoxy resin systems or from the group of epoxy resin systems with the reaction products bisphenol A-epichlorohydrin resins, with a glass fiber from the group of S2 glass fibers.

[0013] In a preferred embodiment of the invention, the resin used is selected from the group of araldites or from the group of epikotes.

[0014] It is further preferred to use an epoxy resin system called Araldite CY179 as the resin base. In an alternative embodiment, an epoxy resin system called EPIKOTE 828 can be used as the resin base.

[0015] According to the invention, the fastening arrangement is designed as a tubular arrangement. Advantageously, the fastening arrangement is preferably designed as a hollow cylindrical tubular arrangement. It further advantageously affects the strength of the fastening arrangement if the surface of the fastening arrangement is not formed as a pure resin layer or as a surface generated by the peel ply, but rather as a ground surface.

[0016] A further aspect of the present invention relates to a cryogenic gas storage device. Accordingly, the invention proposes a cryogenic gas storage device, in particular a cryogenic compressed gas storage device with an inner tank, wherein the inner tank is attached and / or suspended from the wall of the outer tank by means of a fastening arrangement as described above. The use of the fastening devices according to the invention is particularly preferred for a CcH2 compressed gas storage device.

[0017] Other advantageous developments of the invention are specified in the subclaims or are explained in more detail below together with the description of the preferred embodiment of the invention with reference to the figure.

[0018] It shows: Fig. 1 a schematic sectional view through a cryogenic compressed gas storage device.

[0019] In the Fig. 1 shows a schematically simplified embodiment of a cryogenic gas storage device 3. The cryogenic gas storage device 3 has a pressure-resistant inner tank 2 and an outer tank wall 4 surrounding the inner tank 2. The inner tank 2 has a storage space 6 for filling with cryogenic hydrogen (CcH2). Between the tank wall 4 and the shell 2a of the inner tank 2 there is an air space 5, which has a vacuum. By means of the Fig. 1 simplified fastening arrangements 2, the inner tank 2 is fastened to or suspended from the inside of the outer tank wall 4.

[0020] The mounting assembly 1, from which the inner tank 2 of the cryogenic gas storage unit 3 was suspended, is made of a glass fiber-reinforced plastic comprising the following components: a resin from the group of cycloaliphatic epoxy resin systems and a glass fiber from the group of S2 glass fibers. In the present exemplary embodiment, a resin from the Araldite group was selected, specifically a resin designated Araldite CY179.

[0021] In an alternative embodiment, the resin used could also be selected from the group of epicotes.

[0022] It is further provided that the fastening arrangements 1 are designed as tubular arrangements. The surfaces of the fastening arrangements 1 are ground to obtain ground surfaces.

[0023] The invention is not limited to the preferred embodiments described above. Rather, a number of variants are conceivable that utilize the presented solution even in fundamentally different embodiments.

Claims

[1] Fastening arrangement (1) for suspending an inner tank (2) of a cryogenic gas storage device (3) on an outer tank wall (4), wherein the fastening arrangement is made of a glass-fibre reinforced plastic from the following components: - a resin from the group of cycloaliphatic epoxy resin systems or from the group of epoxy resin systems with the reaction products bisphenol A-epichlorohydrin resins; - a glass fiber from the group of S2 glass fibers, wherein the fastening arrangement is designed as a tubular arrangement. [2] Fastening arrangement (1) according to claim 1, characterized by that the resin used is selected from the Araldite group. [3] Fastening arrangement (1) according to claim 1, characterized by that the resin used is selected from the group of epicotes. [4] Fastening arrangement (1) according to claim 2, characterized bythat the resin used is an epoxy resin system called Araldite CY179. [5] Fastening arrangement (1) according to claim 3, characterized by that the resin used is an epoxy resin system called EPIKOTE 828. [6] Fastening arrangement (1) according to one of the preceding claims, characterized by that the surface of the fastening arrangement is designed as a ground surface. [7] Cryogenic gas storage device (3) with an inner tank (2), wherein the inner tank (2) is fastened and / or suspended on the outer tank wall (4) by means of a fastening arrangement (1) according to one of the preceding claims 1-6.

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