Patent Description:
The quest for environmental friendly and renewable energy is one of the most tempting challenges of today. Some proposed solutions relate to wind turbines and solar towers. In International patent application <CIT> efficient energy storage solutions are described, whereby wind turbines or solar towers are towers built of compressed gas pressure vessels.

In the compressed gas pressure vessels forming such wind turbines or solar towers, the energy harvested from wind or solar energy is typically converted to hydrogen gas, thus allowing to store the energy in the form of hydrogen gas. Hydrogen gas can cause hydrogen embrittlement in metal materials. Since the CPV is a constructive part of the tower structure and since the consideration should be that expected service life of the tower would be at <NUM> to <NUM> years, only expensive and difficult to process materials (machining & welding) like for example stainless steel AISI316L could be used for the construction of the CPV.

<NPL>, systems for forming methane at wind turbines or solar towers using stored hydrogen gas. This requires additional production of carbon dioxide, as well as different reservoirs for storing the reagens and the products. Other techniques, wherein hydrogen gas is harvested from a particular tower and converted through chemical reaction in other chemical components are also known.

Consequently, there is room for improving towers, such as wind turbines or solar towers, adapted for storing energy in the shape of gas.

It is an object of embodiments of the present invention to provide good compressed gas pressure vessels for building an energy storage tower for storing hydrogen.

It is an advantage of embodiments of the present invention that an energy storage construction such as an energy storage tower or a substantially horizontal energy storage system can be built based on compressed gas pressure vessels that allow storing hydrogen while avoiding deterioration of the compressed gas pressure vessels. It is an advantage of embodiments of the present invention that compressed gas pressure vessels are provided that can act as constructive parts of the construction such that the construction maintains sufficiently stable over an expected service life of the construction of at least <NUM> to <NUM> years.

It is an advantage of embodiments of the present invention that an energy storage construction can be built using compressed gas pressure vessels made of materials that are relatively cheap and are relatively easy to process.

The present invention relates to a compressed gas pressure vessel suitable for serving as construction element for building energy storage constructions thereof, the compressed gas pressure vessel comprising.

wherein the outer segment is substantially fully encompassing the inner segment. The inner segment suitable for storing hydrogen may have a wall made of a low hydrogen diffusion or permeation material.

The low hydrogen diffusion or permeation material may be any of Aluminum, Aluminum alloy, Polyethylene, a composite material based on carbon, glass or aramide fibers. Alternatively or in addition thereto coatings can be applied to the walls to form a hydrogen permeation barrier. The most favorable coatings are Al/Al<NUM>O<NUM> and double layer Al<NUM>O<NUM>/ Fe-Al coatings. Al-Si or Graphene coatings have shown good permeation barrier properties in recent research papers and therefore also can be used. Such coating can be applied to the inner side of the walls of the inner segment. The coatings may also be lined with such a low permeation material.

Natively grown oxides can be used as permeation barriers as well, in particular Cr<NUM>O<NUM>. These coatings are applied on the inner side of the segment.

According to embodiments of the present invention both an inner segment and an outer segment are present. The inner segment is encompassed by the outer segment. Advantageously, the inner segment and outer segment are concentric along the same longitudinal axis of the segments.

According to embodiments of the present invention, the volume of the inner segment and the outer segment is fixed, i.e. it is not variable.

It is an advantage of embodiments of the present invention that the inner segment and the outer segment can be separated from each other without irreversibly damaging the segments and structures.

In embodiments of the present invention the different segments are suitable for being filled with distinct fluids. In embodiments of the present invention, each fluid, e.g. each gas, may have its own input/output port.

It is an advantage of embodiments of the present invention that the fluid, e.g. gas, stored in the outer segment can be selected such that the fluid cannot destroy or significantly deteriorate the material of which the outer segment is made. The fluid stored in the outer segment can be selected such that it does not or does not significantly oxidizes, reduces or dissolved the material of the outer segment.

The outer segment may be made of a construction steel. It is an advantage of embodiments of the present invention that the outer shell can be made of normal and cheap construction steel, such as for example Steel <NUM>, whereby the material has better mechanical, welding and machining properties. It is an advantage of embodiments of the present invention that the outer segment can carry all or nearly all mechanical loads. The outer segment can comprise substantially more material for the construction than the inner segment.

The outer segment may comprise an inlet for reversibly filling and emptying the outer segment with said fluid different from hydrogen.

The outer segment may be adapted for storing therein and collecting therefrom any of nitrogen gas or carbon dioxide gas.

The compressed gas pressure vessel may comprise a burst valve or a sample valve.

A plurality of inner segments may be provided.

The inlet of the plurality of inner segments may be combined into a single flange or distribution head.

The inner segment may be spaced from the walls of the outer segment by spacers. The spacers may be any or a combination of springs or elastic elements such as for example elastomers or rubbers.

The spacers may be adapted such that the inner segment is moveable for adjusting a position of the inner segment, e.g. for adjusting a sealing position of the inner segment when it is to be connected to another inner segment during construction of an energy storage construction.

The compressed gas pressure vessel may comprise a leakage detector for detecting leakage of hydrogen from the inner segment.

The construction of the inner and outer segment may be adapted for storing hydrogen and the other fluid at substantially the same pressure. It is an advantage of embodiments of the present invention that by balancing the pressure in the inner and the outer segment, the wall of the inner segment can be rather thin. It is an advantage of embodiments of the present invention that the amount of material that is required for forming the inner segment can be limited, which also results in a substantial cost advantage.

The present invention further relates to a component for an energy storage construction, e.g. a tower or substantially horizontal construction, or for a pipeline, the component comprising an assembly of connected compressed gas pressure vessels, wherein the assembly of connected compressed gas pressure vessels comprises one or more first, inner, segments, wherein the one or more inner segments comprise an inlet for filling or emptying the inner segment and wherein the inner segment is suitable for storing hydrogen, and one or more second, outer, segment, the one or more outer segments adapted for being filled with a fluid, different from hydrogen.

The assembly of connected compressed gas pressure vessels may be a plurality of connected compressed gas pressure vessels all have closed head caps, thus all forming individual compressed gas pressure vessels.

The assembly may comprise a plurality of second, outer, segments joint-connected to each other.

The inner segment may be a single segment inserted into the plurality of joint-connected second outer segments.

The inner segment may be an assembly of joint-connected first, inner segments.

The component may comprise distance keepers for aligning the one or more inner segments with respect to the one or more outer segments.

The distance keepers may be installed at the inside of the one or more outer segments or at the outside of the one or more inner segments and/or are installed at positions were inner or outer segments have joint connections.

The compressed gas pressure vessel may be as described above.

The present invention also relates to a pipeline comprising a compressed gas pressure vessel or a component as described above.

The present invention also relates to an energy storage construction such as for example an energy storage tower or a substantially horizontal energy storage construction, the energy storage construction comprising at least one compressed gas pressure vessel as described above as constructive element of the energy construction or a component as described above.

All constructive elements of the energy construction may be compressed gas pressure vessels as described above.

The energy harvesting construction may be a construction supporting solar panels.

Where in embodiments of the present invention solar panels are mentioned, reference may be made to thermal solar panels wherein solar energy conversion is based on heating of a substance by solar energy, reference may be made to photovoltaic cells, or more generally reference may be made to any type of system converting solar energy into another type of energy.

The energy harvesting construction may be a substantially horizontal energy harvesting construction. The energy harvesting construction may be configured for using energy obtained from solar panels for generating hydrogen, for producing ammonia, methane or nitric acid, or for other chemical or physical processes.

The present invention also relates to the use of a compressed gas pressure vessel or component as described above for storing and collecting therefrom hydrogen.

The present invention also relates to the use of a compressed gas pressure vessel or component as described above for storing and collecting therefrom hydrogen and another fluid.

The present invention also relates to the use of a compressed gas pressure vessel or component as described above for the production of a chemical composition by a hydrogenation of hydrogen gas.

The present invention also relates to the use of a compressed gas pressure vessel or component as described above for the production of ammonia.

The present invention also relates to the use of a compressed gas pressure vessel or component as described above for the production of methane.

The present invention also relates to the use of a compressed gas pressure vessel or component as described above for the production of nitric acid.

The present invention also relates to the use of a compressed gas pressure vessel or component as described above for the continuous production of ammonia, of methane or of nitric acid or any other chemical composition, whereby continuous production is a production <NUM> per day, <NUM> days a week, except for maintenance, making use of at least temporary stored hydrogen.

It is to be noted that, whereas in embodiments of the present invention reference is made to a duplex compressed gas pressure vessel or a dual segment compressed gas pressure vessel, the present invention is not limited to compressed gas pressure vessels wherein only two different compounds can be stored, i.e. wherein only two compartments, also referred to as segments, are present. The number of compartments thus does not need to be limited to two different compartments, but is at least two, and can for example be three different compartments, four different compartments, etc..

The wall materials selection (mono-materials, laminates or composites structures) for the inner segment should be done based on the criteria that it should have low hydrogen embrittlement properties (metals) and/or low hydrogen diffusion values, and these at the operating temperatures and operating pressures the dCPV's will be used at.

The material selection for the outer segment is mainly driven by the mechanical, processing (welding, machining), maintenance (anti-corrosion, coating) and strength properties.

In a first aspect, the present invention relates to a dual segment compressed gas pressure vessel. The compressed gas pressure vessel comprises a first, inner, segment, wherein the inner segment comprises an inlet for filling or emptying the inner segment and wherein the inner segment is suitable for storing hydrogen. The compressed gas pressure vessel furthermore comprises a second, outer, segment, the outer segment adapted for being filled with a second gas, different from hydrogen, and the outer segment substantially fully, e.g. except for the inlet of the inner segment, encompassing the inner segment. In other words, the walls of the inner segment do not form the outer wall of the compressed gas pressure vessel. The latter results in the fact that hydrogen is not in direct contact with the outer walls, such that hydrogen cannot cause embrittlement or deterioration of the outer walls of the compressed gas pressure vessel. The latter is advantageous as the outer walls can for example be selected for being the walls that provide the strength to the compressed gas pressure vessel for acting as a constructing element.

In advantageous embodiments, the outer segment of the compressed gas pressure vessel also has an inlet and the compressed gas pressure vessel allows storage and collecting of the second gas, being different from hydrogen. Advantageously such dual storage may be used for storing hydrogen and another gas that can be used in the production of a chemical compound such that the two reagents can be harvested from the same compressed gas pressure vessel.

<FIG> illustrates three examples of a compressed gas pressure vessel according to the first aspect, wherein different configurations for the inlet are shown. In the example shown, the outer segment of the tank is filled with nitrogen gas or carbon dioxide gas <NUM> and the inner segment is filled with the hydrogen gas <NUM>. This way, the material for the outer shell of the CPV could be made of normal and cheaper construction material such as Steel <NUM>, which has better mechanical, welding and machining properties. The outer segment typically may carry all the mechanical loads and may consume most material for the construction. <FIG> shows different construction concepts. The duplex CPV (dCPV) may have a burst valve <NUM> or sample valve.

The material for the inner vessel, in which the hydrogen is stored, can be a low diffusion and/or low permeation hydrogen material, like for example Aluminium, Polyethylene, composite materials (e.g. based on carbon fibers). Or combinations (laminates) of materials, lined metal materials or coated materials using for examples Al/Al<NUM>O<NUM> or double layer Al<NUM>O<NUM>/ Fe-Al coatings. Grown oxides on the metal surface could also being used as permeation barriers, in particular Cr<NUM>O<NUM>.

According to some embodiments, the compressed gas pressure vessel is adapted such that, in use, the pressure should be balanced in the outer and inner segment. This allows the inner segment to have a rather thin wall, which again a substantial cost advantage.

<FIG> shows a configuration with multiple inner segments <NUM>, combined into one flange or distribution head. For some material options this could be an advantageous method to limit the wall thickness or to increase the inner pressure resistance.

<FIG> shows different spacer configurations. The inner segment may be spaced from the walls of the outer segments in different ways. Such spacing removes or reduces possible vibrations generated by the tower structure and prevents that possible vibrations are directly transmitted to the inner segment. During the building of the tower such spacer could facilitate the connection of the different inner segments, for example when they are inline interconnected. If the spacers are springs <NUM> or elastomers <NUM> (eg rubbers), the inner segment could be slightly moveable such as to move into the correct sealing position to connect the next inner segment.

<FIG> it would be advantageous to put a hydrogen detector in the outer segment connection lines downstream of the dCPV. That would allow detecting a possible leak in the inner segment (filled with hydrogen), increasing the safety of the whole tower concept. Even if hydrogen would leak into the outer segment, that would not cause an immediate risk, since typically an inert gas will be stored in the outer segment.

Embodiments of the present invention advantageously can be used in energy harvesting systems wherein hydrogen gas will be converted through chemical reaction in another chemical substance for the energy harvesting.

An example thereof is conversion of hydrogen through chemical reaction with nitrogen into NH<NUM> (ammonia). Such conversion can be performed either at the tower structure or at a fixed or mobile installation near the tower structure. Instead of storing each chemical substance (e.g. hydrogen and nitrogen) separately in a dedicated gas tower, it could be advantageous to store the <NUM> gasses in one or more duplex CPV of the tower structure.

An example thereof is a conversion of hydrogen through chemical reaction with CO<NUM> into CH<NUM> (methane). Such conversion can be performed either at the energy storage construction or at a fixed or mobile installation near the energy storage construction. The CO<NUM> can be either produced by a separate source or may be stored in an energy storage construction. Instead of storing each of the chemical substances (e.g. hydrogen and carbon dioxide) separately in a dedicated gas tower, it could be advantageous to store the <NUM> gasses in one or more duplex CPV of the construction.

In yet another example, conversion of hydrogen through chemical reaction into nitric acid is envisaged.

The present invention also relates to a component for an energy construction, such as for example an energy storing tower. Such a component typically may be referred to as a leg of the energy construction. The component of the energy construction comprises one compressed gas pressure vessel or an assembly of connected compressed gas pressure vessels. The one or more compressed gas pressure vessels comprise one or more first, inner, segments, wherein the one or more inner segments comprise an inlet for filling or emptying the inner segment and wherein the inner segment is suitable for storing hydrogen, and one or more second, outer, segment, the one or more outer segments adapted for being filled with a fluid, different from hydrogen,.

Further standard and optional features will further be illustrated with reference to <FIG>, embodiments of the present invention not being limited thereto.

<FIG> shows examples of legs of a tower. On the left hand side of <FIG>, an assembly of stacked individual dCPV's is shown, with each of the dCPV's having closed head caps. In a vessel the head caps take most of the mechanical forces, that's the reason why the head caps have to be constructed in rather thick material.

To lower the cost of the tower structure, it would be advantageous installing the dCPV in a serial configuration as shown in right assembly in <FIG>. The dCPV's in this exemplary embodiment are joint-connected with flanges or welds and only <NUM> head caps are necessary per tower leg. <FIG> shows the pressure tight connection means <NUM> between two outer wall segments of the dCPV. Less head caps means also more operational storage volume in the complete tower structure. <FIG> also shows the lifting connection point <NUM>, an inner wall <NUM> and an outer wall <NUM>.

Due to the use of flanges or welds, the inner diameter of the outer vessel would be large enough at most positions, to insert a long inner vessel. This inner vessel could be made for example out of Polyethylene, although embodiments are not limited thereto. <FIG> shows an example if the inner Polyethylene vessel is being thermally welded, to form a long vessel. It illustrate a joining technique <NUM> for the inner walls. In case of Aluminium, it could be for example metal inert gas (MIG) or tungsten inert gas (TIG) welded. Another advantage is that due to the thin wall thickness of the inner vessel, inspection means to verify welding seam properties, using Ultrasonic or X-Ray NDE /NDT inspections are much easier to conduct and could be done at the location of the assembly.

Of course the inner vessel will have <NUM> head caps to form a closed pressure vessel. It has been said before; each segment will have its filling/emptying nozzle.

<FIG> shows that it would be helpful, at some points of the long inner segment, to install distance keepers <NUM>, so that the inner vessel is well aligned in the outer vessel and/or reduce possible vibrations of the inner vessel One could even consider installing them where the joint-connections (weld or seal or other type of connection) are located, for example for the inner vessel.

These distance keepers could be installed on the inside of the outer vessel or at the outside of the inner vessel.

As disclosed in <CIT>, it is possible to construct a tower structure by pushing up the tower and adding additional elements at the bottom side. If this technique is used, it could be also used in case the inner tube would show hydrogen or pressure leaks to conduct a repair. The actions taken are pushing upwards the complete tower structure, remove the bottom dCPV, pull out the inner vessel (which probably may have to be cut into sizeable parts to remove them). The latter is illustrated in <FIG>, showing hydraulic lifters <NUM>. When the complete inner vessel is removed, a new inner vessel can be inserted in the dCPV. Assuming a leak would be located at the lower part of the inner vessel, it could be sufficient to just partially remove and replace some defective vessel parts and replace it with a new part. It is to be noted that the inner vessel is most sensitive, since this stores the hydrogen gas.

It further is to be noted that a serial assembly per leg of dCPV's also results in a reduced amount of burst valves, In/Outlet nozzles, easier control of the balancing between the inner and the outer segment.

Whereas with respect to <FIG>, a tower construction has been shown, embodiments of the present invention also relate to a substantially horizontal construction for energy storage. Such a construction may comprise the same characteristics and features as the tower being described above. In some embodiments, such a substantially horizontal construction may be a construction for supporting a solar panel. By way of illustration, embodiments of the present invention not being limited thereto, an exemplary construction is shown in <FIG>. The construction comprises one or more duplex compressed gas pressure vessels <NUM> forming the support for a solar panel <NUM>.

<FIG> illustrates a cluster of a plurality of energy storage constructions comprising solar panels, coupled together to form a full energy storage system. In the system, an electrolyser <NUM> is shown, wherein hydrogen gas <NUM> is produced, whereby the hydrogen gas <NUM> will be stored in one of the vessels of the one or more compressed gas pressure vessels of the structure. In the particular example shown, also an air separation unit <NUM> for producing nitrogen <NUM> is provided, whereby the nitrogen gas <NUM> also can be stored in a vessel of the one or more compressed gas pressure vessel in the structure.

Advantageously, the electrolyser <NUM> and the air separation unit <NUM> may be powered by the solar panels of the system. In this way the solar energy is converted into hydrogen and nitrogen gas, which can be harvested at a later moment in time. This energy conversion allows storage of energy in the form of chemical components.

<FIG> illustrates a system that comprises a field of a plurality of energy storage (clusters) as shown in <FIG>, whereby furthermore a production unit for producing a further chemical composition is provided. In the example shown, the production unit is an ammonia production unit. By selecting the number of hydrogen <NUM> and nitrogen <NUM> storage vessels appropriately, the production of the further chemical composition, such as for example ammonia <NUM>, can be a continuous production, e.g. a <NUM>/<NUM> production. For some further chemical compositions this may be advantageous since the production process may be difficult and/or energy intensive to start or stop. A typical Haber/Bosch reaction is best kept in a continuous operating, without process interruptions. If not, the production yield will be drastically negatively affected.

The produced ammonia <NUM> can also be stored and at regular moments in time been harvested. The above is especially advantages for harvesting energy from remote areas, such as for example for harvesting solar energy from a desert. Solar energy is efficiently produced during the day, but not during night. By conversion of the solar energy during the day towards hydrogen and nitrogen, the two essential basic components are made for generating ammonia, which then can be performed in a <NUM>/<NUM> manner.

In yet another aspect, the component as described above, whereby a single inner vessel segment is used or an assembly of interconnected inner vessel segments is used that are fluidly connected with each other, can be used as component for a pipeline or as a pipeline. It is to be noted that the number of input and output ports in some embodiments of the pipeline embodiments can be limited, e.g. it may be sufficient to have an inlet near the start of the pipeline and an outlet near the end of the pipeline. Other components may be mutates mutandis.

In a further aspect, the present invention relates to an energy storage construction, e.g. an energy storage tower or a substantially horizontal construction being build up from compressed gas pressure vessels, whereby at least one compressed gas pressure vessel is a compressed gas pressure vessel as described in the first aspect. The energy tower thus is adjusted for storing hydrogen. The energy storage construction furthermore may be characterised by features and advantages of the compressed gas pressure vessels as described in the first aspect. In advantageous embodiments, the outer segment of the compressed gas pressure vessel according to an embodiment of the first aspect is adapted for actively storing and collecting a further gas such as nitrogen or carbon dioxide, such that both hydrogen and the further gas can be used in the production of a chemical composition. Such a chemical composition typically may be a composition having a higher density than hydrogen and having an industrial relevance. According to embodiments of the present invention, the energy tower may thus have the capability of storing two different gasses or fluids, one of them being hydrogen. As indicated when describing the compressed gas pressure vessels, hydrogen is typically stored in an inner segment of the dual segment compressed gas pressure vessel, such that diffusion of hydrogen out of the compressed gas pressure vessel is reduced and such that deterioration of the compressed gas pressure vessel by hydrogen, resulting in a reduction of construction strength can be reduced or even avoided. The energy construction furthermore may comprise features of an energy storage tower as described in International patent application <CIT>.

Claim 1:
An energy storage construction system being one or more of a vertical construction, a horizontal construction or a pipeline, the energy storage construction system comprising a compressed gas pressure vessel (<NUM>) being a constructive element of the energy storage construction system,
the compressed gas pressure vessel comprising
- a first, inner, segment (<NUM>), wherein the inner segment (<NUM>) comprises an inlet (<NUM>) for filling or emptying the inner segment (<NUM>) and wherein the inner segment (<NUM>) is suitable for storing hydrogen gas (<NUM>), and
- a second, outer, segment, the outer segment adapted for being filled with and for storing a gas, different from hydrogen gas (<NUM>),
wherein the outer segment is substantially fully encompassing the inner segment, the outer segment of the constructive element thereby being able to carry mechanical loads of the energy storage construction system induced on the constructive element.