EP2630401A1

EP2630401A1 - Method for transporting hydrogen through a natural gas line

Info

Publication number: EP2630401A1
Application number: EP11770703.4A
Authority: EP
Inventors: Dragan Griebel; Anton FÖRTIG
Original assignee: Rehau AG and Co
Current assignee: Rehau Automotive SE and Co KG
Priority date: 2010-10-18
Filing date: 2011-10-12
Publication date: 2013-08-28
Also published as: DE102010048562A1; WO2012052125A1

Abstract

The invention relates to a method for transporting hydrogen (16) through a natural gas line (14), wherein a hydrogen line (10) composed of plastic material is arranged in the natural gas line (14), and for the transport of the hydrogen (16), the hydrogen (16) flows through the hydrogen line (10).

Description

Method for transporting hydrogen through a natural gas pipeline

Background of the invention

The present invention relates to a method for transporting hydrogen through a natural gas line.

Motivated by the increasing shortage of fossil fuels, in particular crude oil, natural gas and coal, alternative technologies are based on the use of hydrogen or hydrogen gas as alternative or additional fuel or energy source. The hydrogen can be prepared in known manner, e.g. from water by electrolysis, the DC power required for the electrolysis being environmentally friendly, e.g. can be provided by solar power plants or wind turbines or tidal power plants. In fuel cells, the recovered hydrogen can react in a controlled manner with the oxygen of the ambient air to form water vapor, wherein the hydrogen emits electrons in this reaction, so that a current can be provided for the supply of any electrical load by this reaction. The resulting waste heat can be used very efficiently in terms of combined heat and power.

Hydrogen as a fuel or energy source can be used in particular for the supply of buildings, such as households or offices, for this purpose, fuel cells are provided in the building or in the vicinity of the building, the supplied hydrogen for power generation for energizing electrical consumers, such as for example, use an electrically powered device, the respective building. In order to transport the hydrogen to the building to be supplied, familiar solutions are usually resorting to existing natural gas networks or natural gas networks, in which case the hydrogen is admixed with the natural gas to be transported via the natural gas pipeline, so that the hydrogen together with the natural gas is transported via the gas pipeline to the building to be supplied. The proportion of hydrogen in the total transported gas mixture is up to about 10 vol .-%. A higher concentration of hydrogen is usually difficult or impossible to achieve. For example, if a hydrogen concentration of approx. 10% by volume is exceeded, certain safety requirements can no longer be fulfilled because embrittlement phenomena occur in metal pipes or metal connections, so that hydrogen concentrations of greater than 10% by volume special and expensive steels would have to be used. This in turn would make it necessary to lay new hydrogen pipes without being able to use an already existing natural gas network or existing natural gas pipelines. The relevant set of regulations for metal pipelines suitable for the conduction of hydrogen is the ASME B31, which outlines the complexity of the facts in terms of its scope. In addition to the preferred hydrogen pipes made of metal, there are also those made of polymer material, usually made of polyethylene (PE). Although these are inert to the action of hydrogen, they have the disadvantage that they are not very suitable due to high permeation rates of hydrogen through the wall.

Underlying task

The present invention has for its object to provide a method for transporting hydrogen through a natural gas line, which is improved over known such methods.

Inventive solution

This object is achieved by a method for transporting hydrogen through a natural gas line with the features of claim 1.

According to the invention, in contrast to known solutions provided in the natural gas line to arrange a hydrogen pipe made of plastic material and to flow through the hydrogen line to transport the hydrogen with the hydrogen. Unlike in known solutions, which use existing natural gas pipelines for transporting hydrogen in such a way that the hydrogen is admixed with the natural gas to be transported via the natural gas pipeline, the process according to the invention can provide a substantial improvement, in particular by avoiding

Embrittlement phenomena in metal pipes, can be achieved. Thus, due to the inertness of a hydrogen conduit made of plastic material, the hydrogen can be passed in nearly pure form through the hydrogen conduit. By inventively arranging the hydrogen pipe made of plastic material in the natural gas line, therefore, the natural gas line can be made suitable for transport with hydrogen in almost pure form. It can therefore be dispensed with in the known method admixing of the hydrogen to the natural gas, which makes an acceptable transport only possible in known methods, since by the transport of hydrogen in this mixture too strong a permeation of very small hydrogen molecules through the wall of the Natural gas pipeline can be avoided.

In contrast to known solutions, where to significantly improve the transport of hydrogen very time and cost new hydrogen pipes would have to be laid because the existing natural gas pipelines made of metal due to their high permeability and susceptibility to corrosion of hydrogen are not suitable for this purpose is based on inventive method, a cost-effective renovation or upgrading an existing natural gas network for the supply of buildings with hydrogen possible, so that can be used advantageously on an existing infrastructure. It is therefore possible to dispense with time-consuming and expensive laying of new hydrogen lines.

In particular, the inventive method for the supply of a building allows the direct use of fuel cells, preferably low-temperature fuel cells, which may have an operating temperature of preferably 80 ° C to 120 ° C and a maximum of 180 ° C. It is not necessary to separate or extract the hydrogen from the hydrogen / natural gas mixture transported via the natural gas line in the case of known solutions and to do so in a very costly and expensive manner. Even a so-called reforming is not required. In a preferred embodiment, the hydrogen has a purity within a range of 80 to 99.999 vol.%, Or within a range of 97 to 99.99 vol.%, Or within a range of 97.5 to 99, 9 vol .-% is. In a practical embodiment of the method according to the invention, the outside of the hydrogen pipe is at least partially applied flat on the inside of the natural gas line, in which case preferably the outside is connected at least partially flat with the inside of the natural gas line. In a particularly practical embodiment, the hydrogen line is introduced by means of a Umstülpverfahrens in the natural gas line. The everting process may preferably be an everting process or inversion process known from the technical field of trenchless pipe laying. In these methods, the hydrogen line before introduction into the natural gas line initially in the form of a tube, by means of Umstülpverfahrens the hose is inserted by compressed air into the natural gas line and the tube interior swept to the outside and provided with the inside of the natural gas via a hose on the Adhesive layer, for example, thermally, cohesively can be connected. In another preferred embodiment, the hydrogen line may also be introduced into the lumen of the natural gas line due to an outer diameter slightly smaller than the inner diameter of the natural gas line, so that the hydrogen line at least partially rests flat against the inside of the natural gas line, in which case preferably the outer side at least in areas, it is connected to the inside of the natural gas pipeline.

Portions of the hydrogen line to be connected to each other can advantageously be easily connected by means of fittings and sliding sleeves. Fittinge and sliding sleeves can be made of brass or brass alloys or polymer material. Within the scope of the permeation rates demonstrated for this invention, it has been shown that fittings which connect polyethylene hydrogen pipes and are secured by sliding sleeves have the following values:

Metal-plastic composite pipe (MKV) / polymer fitting

Leakage rate 1, 5 x 10 exp -3 l / d Metal-plastic composite pipe (MKV) / brass fitting

Leakage rate 9 x 10 exp -5 l / d.

Another way of connecting sections of the hydrogen pipe is to weld the ends of the sections together. In the welding, which takes place by means of a mirror welding process "blunt at the ends of the sections, or by means of welding sleeves, which accomplishes the connection of an end portion of the line on its outer surface, cohesive connection of the sections are achieved. These cohesively connected sections of the hydrogen line have a

Permeation on, which essentially corresponds to that of the hydrogen line, that is particularly low.

In a further particularly preferred embodiment, a hydrogen line is used, which consists at least partially of PE-X (cross-linked polyethylene).

A PE-X existing hydrogen pipe is particularly temperature resistant and mechanically resistant, so that the introduction of the hydrogen line in the natural gas line can be carried out particularly easily, in addition, such Hydrogen line withstands higher temperatures, which can occur, for example, in industrial plants. Here, a hydrogen line is particularly preferred, which consists of PE-X or PE-X, which is radically crosslinked, in particular a hydrogen line, which consists of PE-Xa (peroxide crosslinked PE) or contains PE-Xa, can be advantageously used ,

In a further particularly advantageous embodiment it can be provided that a hydrogen line is used, the inside of which is provided with a hydrogen barrier layer.

A hydrogen barrier layer on the inside of the hydrogen line, ie on the side facing the lumen of the hydrogen line, advantageously increases the diffusion-tightness of the hydrogen line, so that the permeation and thus the loss of hydrogen from the hydrogen line is reduced.

It is also possible to arrange the hydrogen barrier layer on the outside of the hydrogen line, ie on the side facing away from the lumen of the hydrogen line. It is also possible that both the inner sides, as well as the outside of the hydrogen line has a hydrogen barrier layer. In the context of the present invention it can be provided that the hydrogen barrier layer consists at least partially of polysilazane.

The selection of a polysilazane as a hydrogen barrier layer on the inside of the hydrogen line has a particularly high diffusion resistance to hydrogen. Thus, with the provision of a polysilazane barrier layer on the inside of the hydrogen line, a permeation rate of 0.4 to 0.6 cm ³ * mm / m ² * d * atm, where the

Permeation rate for an aluminum foil as a hydrogen barrier at 0.2 cm ³ * mm / m ² * d * atm.

On the other hand, a tube made of LDPE (Low Density Polyethylene) has a permeation rate of 200 cm ³ * mm / m ² * d * atm.

Another hydrogen barrier is polyvinyl alcohol (EVAL, EVOH).

The present invention also most preferably comprises a hydrogen conduit formed in the form of a multilayer conduit consisting of at least two interconnected layers.

By selecting the layers connected to one another in the pipeline, adaptation to the requirement profile placed on the pipeline, such as, for example, high abrasion resistance or high UV resistance or the like, can be implemented particularly easily.

In an advantageous embodiment of the invention can be provided that at least one layer consists at least partially of polyolefin.

The provision of a layer structure of the pipeline in which at least one layer consists at least partly of polyolefin has the advantage that this layer can be produced favorably in a plastic molding process, for example an extrusion process.

In a further advantageous embodiment of the invention can be provided that a hydrogen line comprises a metal layer, which is designed in particular very thin. Thus, a metal layer, for example of aluminum or another metal, a thickness of 1 to 50 pm, more preferably a thickness of 5 to 30 μιτη have. A hydrogen conduit in such a configuration, in which a thin metal layer is connected to at least one layer of polymer material, is referred to as a metal-plastic tube (MKV tube). Such an MKV pipe can be integrated into an existing natural gas tion be inserted or introduced in the everting process in the natural gas line, because the thin metal layer tolerates the bending stress occurring during the Stülpverfahren without damage. Application finds the invention in the upgrading of an existing natural gas network for the supply of hydrogen. In particular, such a hydrogen pipe network can be built from an existing natural gas network, without significant civil engineering work, trenching or earth movements are necessary. Only at a few selected locations, for example at junctions, are construction pits to be made.

The upgrading of the natural gas network to a hydrogen network is carried out by introducing a hydrogen line into a natural gas line.

Brief description of the drawings

Embodiments of the invention will be explained in more detail with reference to the accompanying drawings. It shows:

1 is a schematic representation for illustrating the introduction of a hydrogen pipe made of plastic material in a natural gas line by means of a Umstülpverfahrens,

FIG. 2 shows a schematic illustration for illustrating the transport of hydrogen through a hydrogen line arranged in a natural gas line, and FIG

3 and 4 each show a schematic sectional view of a natural gas line, in which by means of a Umstülpverfahrens a hydrogen pipe made of plastic material was introduced.

Figs. 1 and 2 serve to illustrate the method according to the invention for the transport of hydrogen through a natural gas line. According to the inventive method, a hydrogen line is arranged in plastic material in a natural gas line and the hydrogen line is flowed through for the transport of hydrogen from the hydrogen. FIG. 1 here illustrates the step of arranging or introducing a hydrogen line 10 made of plastic material into a natural gas line 14 laid in the ground 12 by means of a known everting method or inversion method. In these processes, the hydrogen pipe 10 is initially present in the form of a hose 10 prior to introduction into the natural gas pipe 14, whereby by means of the everting process the hose 10 can be introduced into the natural gas pipe 14 by compressed air and the hose interior is turned outwards and with the inside 15 of the natural gas line 14 via a provided on the hose 10 adhesive layer (not shown here) is materially connected. The tube 10 is thereby supplied through the interior of a supply line 13 of the natural gas line 14 and is wound on a roll (not shown here), which is located inside a pressurizable container 1 1, to which the supply line 13 is connected. FIG. 2 illustrates the flow through a hydrogen line 10 with hydrogen 16, which was previously arranged or introduced in a natural gas line 14, which is laid in the ground 12. The hydrogen line 10 serves to supply a building 18 with pure hydrogen from a hydrogen tank 19, with a low-temperature fuel cell 20 being provided for generating DC power from the hydrogen supplied via the hydrogen line 10 in this exemplary embodiment. The generated direct current can be converted into alternating current via an inverter, not shown here, so that the hydrogen 16 can be used to supply conventional electrical consumers 22, such as here in the form of a lamp. 3 shows a schematic sectional view of a natural gas line 14 into which a hydrogen line 10 made of plastic material has been introduced by means of an everting process.

4 shows a schematic sectional view of a natural gas line 14, in which by means of an everting process, a hydrogen line 10 made of plastic material has been introduced, which consists of two interconnected layers 24.

- Claims - LIST OF REFERENCE NUMBERS

10 hydrogen line

1 1 container

12 soil

13 supply line

14 natural gas pipeline

15 inside gas pipeline

16 hydrogen

18 buildings

19 hydrogen tank

20 low-temperature fuel cell

22 consumers

24 shift

Claims

claims

1. A method for transporting hydrogen (16) through a natural gas line (14), wherein in the natural gas line (14) a hydrogen line (10) made of plastic material is arranged and the hydrogen line (10) for transporting the hydrogen (16) from the hydrogen ( 16) is flowed through.

2. The method according to claim 1, characterized in that the hydrogen (16) has a purity within a range of 80 to 99.999 vol .-%, preferably within a range of 97 to 99.99 Vol .-%, particularly preferred within a range of 97.5 to 99.9% by volume.

3. The method according to claim 1 or 2, characterized in that the outside of the hydrogen line (10) at least partially flat on the inside (15) of the natural gas line (14) is applied.

4. The method according to claim 3, characterized in that the outside at least partially flat with the inside (15) of the natural gas line (14) is connected.

5. The method according to any one of the preceding claims, characterized in that the hydrogen line (10) by means of an everting process in the natural gas line (14) is introduced.

6. The method according to any one of the preceding claims, characterized in that a hydrogen line (10) is used, which consists at least partially of PE-X.

7. The method according to any one of the preceding claims, characterized in that a hydrogen line (10) is used, the inside and or outside of which is provided with a hydrogen barrier layer.

8. The method according to claim 7, characterized in that the hydrogen barrier layer consists at least partially of polysilazane.

9. The method according to any one of the preceding claims, characterized in that a hydrogen line (10) is used, which is formed in the form of a multilayer wire, which consists of at least two interconnected layers (24).

10. The method according to claim 9, characterized in that at least one

Layer (24) consists at least partially of polyolefin.