IT202100000395A1 - CONTAINMENT DEVICE FOR FUEL CELL SYSTEMS. - Google Patents

Description

?Containment device for fuel cell systems.?

DESCRIPTION

The present invention relates to a containment device for fuel cell systems.

The fuel cell systems are composed of a stack, with different applicable technologies, and the auxiliary systems necessary to supply the fuel, the oxidizer, the cooling, the electrical supply of the auxiliaries, the electrical connections for the current produced by the stack and control of the same.

Pi? in detail, in this description:

- the term ?fuel cell stack?, means the basic component made up of bipolar plates and membranes together with the connection manifolds;

- with the wording ?fuel cell module? means the basic element of a plant and consists of a fuel cell stack to which are added the fuel cell stack control elements such as valves, bypass, humidifier, recirculation, etc.;

- with the wording ?fuel cell system? you mean the minimum unit? able to produce energy autonomously, thanks to the help of all the active auxiliary components such as pumps, compressors, actuators, exchangers, and includes one or more? fuel cell modules;

- with the wording ?fuel cell system? does it mean the union of all the components necessary for the functioning of one or more? fuel cell systems or, more? simply, it means the set of all the elements present in a fuel cell engine room.

All types of fuel cell systems operate with hydrogen or hydrogen-rich syngas as fuel, therefore they are susceptible to gas leaks from the stack, joints, ancillary systems.

Gas by its nature? explosive and requires the adoption of protection strategies against the formation of explosive atmospheres in the premises where the fuel cell systems are installed.

The protection strategies can be of two types: gas-tight system; ventilated system.

The first type of protection? difficult to obtain and expensive, it is adopted in exceptional cases when it is not? ventilation can be used.

The second type of protection, in which ? often considered the possibility to exploit the natural ventilation that requires the installation of the system outdoors and not indoors or the forced ventilation of the entire room where the system? installed, ? the "P? common and, in the case of closed rooms, requires an expenditure of energy for the supply of forced ventilation which depends on the volume to be ventilated.

These fuel cell systems are not free from drawbacks, among which the fact that there are no standard strategies or systems which allow the problem described above to be tackled.

In fact, the market offers fuel cell systems with auxiliaries, leaving the problem of protection against the formation of explosive atmospheres to system integrators.

Furthermore, there is no uniformity? between international standards and norms.

The same norms and standards can differ depending on whether we are dealing with stationary or mobile applications.

In general, natural ventilation is used for mobile plants of small and medium power.

Stationary and large power plants that require the installation of more? fuel cell systems in a single generally closed room, instead require the adoption of a protection strategy with forced ventilation for the entire room.

Many technical solutions adopted today consider ventilation of the fuel cell stack or module only, leaving the integrator to manage safety (and therefore ventilation) for any gas leaks generated by the rest of the system.

The aim of the present invention is to provide a containment device for fuel cell systems to protect against the creation of explosive atmospheres.

Within the scope of this aim, an object of the present invention is to provide a containment device capable of reducing to a minimum the energy consumption required for ventilation while reducing at the same time the volume to be ventilated.

Another object of the present invention is to provide a containment device which is capable of giving the most? extensive guarantees of reliability? and safety in use.

Another object of the present invention is to provide a containment device which can be made with technologies per se? known and which therefore has low construction costs.

The task set out above, as well as? the objects mentioned and others which will become apparent hereinafter are achieved by a containment device for fuel cell systems, comprising a first protective box-shaped body suitable for containing at least one fuel cell module and a plurality of of auxiliary components for the correct functioning of said at least one fuel cell module; said first box-like body being provided with at least one inlet opening and at least one outlet opening respectively for the flow of ventilation air inside said first box-like body; characterized in that said at least one inlet opening and said at least one outlet opening are located, with respect to the orientation of said first box-shaped body during its normal use, in the lower part and in the upper part of said first box-shaped body in such a way that said flow of ventilation air occurs substantially in the opposite direction to the direction of the earth's gravitational field; said first box-like body comprising an internal profile of said upper part of the converging type for conveying said ventilation air in the direction of said at least one outlet opening.

Further characteristics and advantages will become clearer from the description of a preferred, but not exclusive, embodiment of a containment device for fuel cell systems and of its variants, illustrated by way of example and not of limitation with the aid of the enclosed drawings, consisting in figures 1 to 7.

Pi? in detail, with particular reference to figure 1, ? schematized a fuel cell plant, globally indicated with the reference number 1, which for example can? be of the PEM type (acronym of the Anglo-Saxon term ?Proton Exchange Membrane), i.e. of the low temperature type.

This plant 1 ? composed of three main lines: the anodic line 2, for the fuel where is distinguished a fuel input 3 and a fuel or vent 4 output, which often ? used for the exit of the nitrogen produced by the stack; the cathodic line 5, for the comburent which generally ? composed of air where a combustion inlet 6 and a combustion outlet 7 can be distinguished, and the cooling line 8, carried out for example using demineralised water or technical fluids (water and specific glycol), where ? possible to distinguish a cooling input 9 and an output 10.

Together with other auxiliary components, necessary to allow the operation of the stack (including pipes, electric power cables, electric power cables, control cables, exchangers, water separators, valves, electronic control boards, measurement sensors voltage, current, pressure, temperature, hydrogen and other) the three lines 2, 5 and 8 and their components schematize the fuel cell module 11, which represents the minimum unit? of autonomous energy production.

The fuel cell module 11, together with its active auxiliary components, define the fuel cell system which ? enclosed inside the first protective box-shaped body 12 which ? equipped with lower openings 13 for the entry of ventilation air and upper openings 14 for the exit of ventilation air.

What is the fuel cell system? defined ? equipped with condensation systems and separation of the reaction water on the anode side which divide the gaseous vent 4 from the liquid part 15. The same thing? present on the cathode side separating the gaseous part 16 from the liquid part 17.

With particular reference to figure 2, in which an evolution of the plant represented in figure 1 is represented, in which, as already? said, can? present the auxiliary components of the fuel cell system inside the same first box-like body 12.

This configuration satisfies the safety regulations required for a fuel cell plant or a fuel cell plant engine room.

In fact, these safety regulations in some cases consider the possibility? to have combustible gas leaks (hydrogen or syngas) also from the fluid lines that are in contact with the anodic line (cathodic line and cooling) and therefore may previously require the installation of the auxiliaries of the non-anodic lines in areas equipped with protection by the formation of an explosive atmosphere.

Therefore this configuration makes it possible to segregate in a single space all the active components that come into direct or indirect contact with the hydrogen also thanks to the decoupling of the fuel cell system cooling line from that of the fuel cell system by means of a heat exchanger heat 18 on the cooling line 8 in order to make the connections to the outer box 19 secure. This requires the creation of an internal cooling line equipped with an internal pump 20 and various auxiliaries including filters 21.

An added benefit of the separate internal cooling system ? represented by the possibility to use the specific technical coolant for the fuel cell (expensive) only for the internal circuit, allowing the use of another liquid for the external circuit.

Furthermore, ? a collection tank 22 of the reaction water is provided which allows to add a second degree of separation between the gaseous part 16 from the liquid 17 of the cathode side, as well as? the gaseous vent 4 from the liquid part 15 of the anodic side; reducing the gaseous outputs from two to one cos? such as liquid ones from two to one, but above all by making the liquid outlet line gas-free.

A collection tank 22 for the reaction water which is sufficiently large and of suitable shape and installation (with respect to the direction of the force of gravity), allows, through a level sensor, to guarantee the absence of gas in the outlet line.

With particular reference to figure 3, ? shown an enlarged detail of the anodic line 5.

Advantageously, for the inlet of the combustion agent 6, ventilated jacketed pipes 24 or double-walled pipes with a nitrogen-tight interspace can be used. These pipes, being able to hold back a possible gas leak having an external pipe and an internal pipe, allow to downgrade the environment in which they are installed by reducing or excluding the need for an external pipe. to have forced ventilation in the room they pass through. Being pipes of complex realization, we try to minimize their use, therefore concentrating all the potential sources in a single point allows us to reduce the use of this type of pipes as much as possible, simplifying the fuel cell system.

In this way ? It is possible to simplify the installation of fuel cell systems by making sure to contain inside the first box-like body 12 not only the fuel cell module but also all the elements critical to the formation of the explosive atmosphere of a fuel cell system.

Also, like this? It is possible to assemble the fuel cell system according to what is shown in figure 2 since it provides for the presence inside the first box-like body 12 of all the active components which come into direct or indirect contact with the hydrogen. To prevent the electrical and control components from coming into contact with potentially explosive gases acting as an ignition, the electrical and control part 23 ? separate from the fluid mechanical part.

With particular reference to figure 4, ? shown an enlarged detail of figure 2.

Advantageously, at the output of the cathode line 5 ? provided a cathodic ejector 25 installed inside the first box-shaped body 12.

At the primary input of the cathode ejector 25 ? connected the cathodic discharge of the stack, i.e. to the outlet of the liquid phase separator located downstream of the comburent 7.

Consequently, at the secondary entrance of the cathode ejector 25 ? connected to the intake outlet of the box-shaped body 12.

The operating principle of the cathodic ejector 25 provides that a fluid connected to the primary inlet with sufficient energy (given by the pressure) generates a suction flow on the secondary inlet. By exploiting this principle, the outlet 28 of the cathodic ejector 25 is made up of the fluid to the cathodic discharge (depleted air, primary) and the ventilation air (air, secondary).

With particular reference to figure 5, an alternative configuration to the one presented in the previous figures 2 and 4 is represented which envisages the use of two different suction strategies for the explosive gases dispersed inside the first box-shaped body 12, thus to realize a double ventilation strategy with a double separation between the fuel cell module and the fuel cell system.

Pi? in detail, ? passive aspiration is provided through the use of the cathodic ejector 25 and active aspiration through the drawing of the reaction air inside the external box 19 by means of a compressor 30.

To make this configuration effective and useful? a second protective box-shaped body 29 is provided for containing the fuel cell module 11 and separating the two suction circuits: the cathode ejector 25 connected to the second box-shaped body 29 of the fuel cell module 11 and the compressor 30 connected to the first body box 12.

In fact, the cathode ejector 25 draws air from the second box-shaped body 29 since its secondary inlet is? connected to the ventilation air outlet 36 of the second box body 29 of the fuel cell module 11 and the compressor 30 of the fuel cell module 11 draws air from the first box body 12 through the filtered inlet 31.

In other words, the first box-shaped body 12 ? ventilated thanks to the fact that c'? an inlet and an outlet of the air flow and the second box-like body 29 ? placed in vacuum as the ejector generates a vacuum which sucks up any possible leaks.

? it is good to underline that what has just been described defines passive and automatic strategies thanks to the fact that they are functional only if and when the stack ? working.

Indeed, if the stack ? off, isn't there? hydrogen in circulation and not c'? suction and if the compressor or the ejector breaks, the system does not work and shuts down.

This strategy allows to segregate the main source of potential hydrogen emission (the fuel cell module with the active or passive anode recirculation system) from the rest of the components of the fuel cell system.

Furthermore, to make this configuration effective and useful ? an air intake with respective filter 31 is provided, installed inside the case of the fuel cell system. The air intake from inside the case makes it possible to generate an internal intake with a flow of fresh air from a ventilation grille 32, placed in correspondence with the lower openings 13, to the compressor intake 30.

The use of two suction systems also allows:

- optimize the layout of the fuel cell system components;

- optimizing the geometry of the external box to convey the air from the ventilation grille 32 to the air intake filter 31 of the compressor 30;

- optimizing the arrangement of the components of the fuel cell module 11;

- optimize the geometry of the fuel cell module box 11.

The same configuration minimizes the suction volume to the cathode ejector 25, making it more? efficient the same component, which has the dual function of generating a pressure drop at the secondary inlet and a back pressure at the cathodic outlet (necessary for the operation of the fuel cell) connected to the primary inlet. The reduction of the suction volume at the secondary inlet of the cathodic ejector 25 allows to use a cathodic outlet flow with a lower pressure allowing to use this solution also for non pressurized (low pressure) fuel cells.

With particular reference to figures 6 and 7, for greater clarity, the two ventilated areas are shown separately.

However, ? good to consider that, depending on the construction specifications of the auxiliary components, part of this pu? selectively be contained within the first or second box-like body 12 and 29.

Ultimately, the device 1 for fuel cell systems comprises a first box-shaped protective body 12 suitable for containing at least one fuel cell module 11 and a plurality of fuel cells. of auxiliary components for the correct functioning of the fuel cell module 11.

Pi? in detail, the first box-shaped body ? equipped with at least one inlet opening 13 and at least one outlet opening 14 respectively for the flow of ventilation air inside the first box-like body 12.

According to the invention, the inlet opening 13 and the outlet opening 14 are located, with respect to the orientation of the first box-shaped body 12 during its normal use, in the lower part and in the upper part of the latter in such a way that said flow of ventilation air takes place substantially in the opposite direction to the direction of the earth's gravitational field.

Advantageously, the first box-shaped body 12 comprising an internal profile of said upper part of the converging type for conveying the ventilation air in the direction of the outlet opening 14.

Conveniently, for systems of large dimensions pu? be provided for an inspection door, while for configurations pi? small ? considered a non-inspectable case. In both cases they are considered semi-watertight cases (IP 65/66) capable of allowing air to enter from the ventilation grille only.

For large systems, as far as the inlet opening 13 is concerned, this can be defined by a ventilation grille 32 obtained on the inspection door.

Advantageously, ? at least one cathodic ejector 25 is provided, located inside the first box-shaped body 12 in correspondence with the cathodic discharge of the fuel cell module 11 for recovering the energy possessed by said cathodic discharge.

This cathode ejector 25 ? connected to the inlet opening 14 for the facilitation of said air ventilation.

Further, ? provided at least a first condensation and separation module 33 of the reaction water connected to the anode discharge of the fuel cell module 11 which? also contained in the first box-shaped body 12 for the removal of said excess reaction water so as not to flood the fuel cell module 11 and to reduce the volume of water circulating in the first box-shaped body 12.

This second aspect becomes important when the cathode ejector 25 is used for recirculation. Almost never is considered the fact of separating the liquid phase from the gaseous one to isolate the hydrogen. Doing it inside the first box-shaped body 12 allows the reaction water to be managed as a non-dangerous source.

Similarly, ? provided at least a second condensation and separation module 34 of the reaction water connected to the cathodic discharge of the fuel cell module 11 which is also contained in the first box-shaped body 12 for the removal of said excess reaction water in such a way as to reduce atmospheric pollution and to separate the gaseous part where hydrogen could potentially enter in the event of a cell rupture.

Conveniently, ? at least one cooling module of the fuel cell module 11 and of the auxiliary components and at least one cooling module of the fuel cell system, intended as a whole of the fuel cell module 11 and its auxiliary components are provided.

These cooling modules define the cooling line 8 and are separated from each other by a heat exchanger 18 so as to add a further degree of safety by making the contact of the cooling line of the fuel cell system twice as indirect.

Further, ? a collection tank 22 is provided for the water contained in the first box-shaped body 12 and operatively associated with the condensation and separation modules 33 and 34 in such a way as to add a second degree of separation of the reaction water circuit leaving the cell module fuel 11 and its ancillary components.

Pi? in detail, the safety due by the collection tank 22 and by the condensation and separation modules 33 and 34 ? permitted by means of the liquid/gas interface and control via a level sensor in the collecting tank 22.

How already? said, jacketed pipes 24 of the ventilated or double wall type are also provided with a nitrogen-tight interspace defining the anodic lines of the fuel cell module 11 and of the auxiliary components.

Pi? specifically, these jacketed pipes can be used for external connections to the containment device 1 and only on the anodic and/or anodic purge and/or cathodic discharge line.

Pi? in detail, the integration of all the auxiliary components, also those for liquid/gaseous phase separation inside the first box-shaped body 12, allows to reduce the connections and therefore the complication of the plant.

In other words, ? possible to reduce the number of pipes containing explosive gas in the fuel cell system.

The segregation in a single semi-sealed and aspirated container body of the entire fuel cell system, i.e. of the assembly given by the fuel cell module 11 and its auxiliary components, allows the environment to be certified as a non-hazardous area in which the system equipped with this containment box? installed, with a considerable advantage from the point of view of safety management.

In particular, ? forced ventilation of the entire "engine room", which is very expensive from an energy point of view, can be avoided.

The only source of danger for the generation of the explosive atmosphere remains the fuel pipe and to a lesser extent the anodic/cathodic purge.

Therefore using the pipes conveyed or jacketed? Is it possible to isolate them making the area safe by excluding the need? to use forced ventilation.

Minimizing the use of this piping greatly simplifies the installation.

Therefore the joint use of the solutions described up to now allows to maximize the advantages of the invention since it allows to minimize the dangerous points, reducing the use of pipes containing explosive gas to two.

How already? said, the electrical components 23, i.e. the electrical control and management part 23 ? separated from the mechanical and/or fluid dynamics components.

In this way, a possible loss of hydrogen from the fluid components cannot? reach the electrical and electronic components, avoiding the risk of explosion a priori.

In the case of systems pi? complex, can be expected more? fuel cell modules 11 and auxiliary components, each contained in a second protective box-shaped body 29 adapted to insulate each fuel cell module 11 with the respective auxiliary components.

Conveniently, the first box-like body 12 is adapted to insulate the set of fuel cell modules 11 and their auxiliary components placed inside the respective second box-shaped body 29.

In the end, ? at least one suction module is provided for suction inside the external box 19 by means of a compressor 30, or of the cathodic air inside the first box-shaped body 12.

In this way, ? It is possible to realize two independent ventilations dedicated, respectively, to the internal ventilation of the first box-shaped body 12, precisely by means of the aspiration module mentioned above, and of the second box-shaped body 29, by means of the cathode ejector 25.

Yes ? in practice ascertained as the containment device for fuel cell systems achieves the task, as well as? the intended purposes, as it allows to secure fuel cell systems to protect against the creation of explosive atmospheres. Furthermore, thanks to the double ventilation and the technical solutions described ? possible to minimize the energy consumption required for ventilation while reducing the volume to be ventilated.

The containment device for fuel cell systems, so? conceived, ? susceptible to numerous modifications and variations, all of which are within the scope of the inventive concept.

Furthermore, all the details may be replaced by other technically equivalent elements.

In practice, the materials used, provided? compatible with the specific use, as well as? the contingent dimensions and shapes may be any according to the requirements.

Claims (11)

1. Containment device (1) for fuel cell systems, comprising a first box-like body (12) suitable for containing at least one fuel cell module (11) and a plurality of of auxiliary components for the correct functioning of said at least one fuel cell module (11); said first protective box-shaped body being provided with at least one inlet opening (13) and at least one outlet opening (14) respectively for the flow of ventilation air inside said first box-shaped body (12); characterized in that said at least one inlet opening (13) and said at least one outlet opening (14) are located, with respect to the orientation of said first box-shaped body (12) during its normal use, in the lower part and in the upper part of said first box-shaped body (12) in such a way that said flow of ventilation air occurs substantially in the opposite direction to the direction of the earth's gravitational field; said first box-like body (12) comprising an internal profile of said upper part of the converging type for conveying said ventilation air in the direction of said at least one outlet opening (14). 2. Containment device (1) according to claim 1, characterized in that it comprises at least one cathodic ejector (25) located inside said first box-shaped body (12) in correspondence with the cathodic discharge of said at least one fuel cell module ( 11) for the recovery of the energy possessed by said cathodic discharge; said cathode ejector (25) being connected to said at least one outlet opening (14) for the facilitation of said air ventilation. 3. Containment device (1) according to claims 1 or 2, characterized in that it comprises at least a first condensation and separation module (33) of the reaction water connected to the anode discharge of said at least one fuel cell module ( 11); said first condensation and separation module (33) being contained in said first box-shaped body (12) for the removal of said excess reaction water so as not to flood said at least one fuel cell module (11) and to reduce the volume of water circulating in said first box-like body (12). 4. Containment device (1) according to one or more? of the preceding claims, characterized in that it comprises at least one second condensation and separation module (34) of the reaction water connected to the cathodic discharge of said at least one fuel cell module (11); said at least one second condensation and separation module (34) being contained in said first box-shaped body (12) for the removal of said excess reaction water in such a way as to reduce atmospheric pollution and to separate the gaseous part where potentially in the event of a cell rupture, hydrogen could enter. 5. Containment device (1) according to one or more? of the preceding claims, characterized in that it comprises at least one cooling module of said at least one fuel cell module (11) and of said auxiliary components and at least one fuel cell system cooling module; said cooling modules (33, 34) being separated from each other by a heat exchanger (18). 6. Containment device (1) according to one or more? of the preceding claims, characterized in that it comprises a water collection tank (22) contained in said first box-shaped body (12) and operatively associated with said at least one first condensation and separation module (33) and at least one second condensation module and separation (34) in such a way as to add a second degree of separation of the outgoing reaction water circuit from said at least one fuel cell module (11) and from said auxiliary components. 7. Containment device (1) according to one or more? of the preceding claims, characterized in that it comprises jacketed pipes of the ventilated or double wall type with a nitrogen-tight cavity defining the anodic lines of said at least one fuel cell module (11) and of said auxiliary components. 8. Containment device (1) according to one or more? of the preceding claims, characterized in that it comprises an electrical component (23) and a mechanical and/or fluid dynamic component separated from each other. 9. Containment device (1) according to one or more? of the preceding claims, characterized by the fact that it comprises a plurality? of said at least one fuel cell module (11) and of said auxiliary components and by the fact of comprising a second protective box-shaped body (29) able to insulate each of said fuel cell modules (11) with the respective of said auxiliary components; said at least first box-shaped body (12) being adapted to insulate the assembly of said fuel cell modules (11) and of said auxiliary components. 10. Containment device (1) according to one or more? of the preceding claims, characterized in that it comprises at least one cathode air suction module (30) inside said first box-shaped body (12). 11. Containment device (1) according to one or more? of the preceding claims, characterized in that it comprises two independent ventilations dedicated, respectively, to the internal ventilation of said first box-shaped body (12) and of said second box-shaped body (29); said first box-shaped body (12) being ventilated by said at least one suction module (30) and said second box-shaped body (29) being ventilated by said cathode ejector (25).