DESC:FIELD
The present invention relates to systems for supplying hydrogen to fuel cells.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
It is desired that hydrogen should be supplied to a fuel cell for the purpose of carrying out an electrochemical reaction in a manner such that controlled electricity generation can take place. Consecutively, it is also desired that the health of the fuel cell is maintained and at the same time the fuel cell is isolated.
There is therefore felt a need for a system that caters to the aforementioned requirements.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to provide a system for supplying hydrogen to a fuel cell stack.
Another object of the present disclosure is to provide a system which provides safety isolation, particularly in-situ safety isolation of the fuel cell.
Yet another object of the present disclosure is to provide a system which can control pressure or flow or both, particularly in-situ pressure or flow or both of hydrogen supplied.
Still another object of the present disclosure is to a system which can measure recirculation flow, particularly in-situ recirculation flow of hydrogen supplied.
One object of the present disclosure is to provide a system which can measure redundant and body fused pressure and temperature of hydrogen.
Another object of the present disclosure is to provide a system which facilitates removal of moisture, particularly in-situ moisture.
Yet another object of the present disclosure is to provide a system which facilitates removal of unwanted gases, particularly in-situ unwanted gases from the anode of the fuel cell.
Still another object of the present disclosure is to a system which can detect in-situ hydrogen leak and smoke.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure envisages a system for supplying hydrogen to a fuel cell stack, wherein hydrogen is supplied to the fuel cell stack from a hydrogen storage unit. The system comprises a system pressure sensing unit provided in the storage tank, a hydrogen isolation valve provided downstream to the system pressure sensing unit in fluid communication with the hydrogen storage unit, and a heat exchanger provided upstream of the fuel cell stack and in fluid communication with the hydrogen isolation valve. The system pressure sensing unit is configured to detect the pressure of hydrogen in the storage tank, and is further configured to generate a first sensed signal. The hydrogen isolation valve is configured to allow metered flow of hydrogen therethrough, based on the first sensed signal. The heat exchanger is configured to pre-heat the received hydrogen. The heat exchanger is further configured to supply the pre-heated hydrogen to the fuel cell stack to facilitate generation of power by the fuel cell stack.
In an embodiment, the system includes a pressure control valve provided downstream to the heat exchanger. The pressure control valve is configured to detect the pressure of the pre-heated hydrogen supplied from the heat exchanger.
In another embodiment, the system includes a stack inlet pressure sensing unit provided downstream to the pressure control valve. The stack inlet pressure sensing unit is configured to allow metered flow of hydrogen to the fuel cell stack, based on the second sensed signal.
In yet another embodiment, the hydrogen isolation valve and the stack inlet pressure sensing unit are flow regulating valves configured to regulate metered flow of pre-heated hydrogen to the fuel cell stack.
In still another embodiment, the hydrogen isolation valve and the stack inlet pressure sensing unit are configured to be connected to the system pressure sensing unit in series.
In an embodiment, the heat exchanger is configured to pre-heat the received hydrogen to fuel cell stack temperature.
In one embodiment, the system includes a cooling unit having a coolant configured to be circulated through the fuel cell stack to facilitate dissipation of heat absorbed by hydrogen in the fuel cell stack during generation of power.
In an embodiment, the system includes a recirculation unit configured to be in fluid communication with the fuel cell stack. The recirculation unit is configured to receive the unused heat dissipated hydrogen from the fuel cell stack. The recirculation unit is further configured to facilitate transfer of the heat dissipated hydrogen to the hydrogen storage unit.
In another embodiment, the recirculation unit includes a water separator. The water separator having a moisture detection sensor configured to detect presence of moisture in the heat dissipated hydrogen, and at least one purge valve configured to remove moisture diffused in the heat dissipated hydrogen.
In yet another embodiment, the recirculation unit includes an anode recirculation flow measurement mechanism configured to selectively allow passage of the moisture-separated, heat dissipated hydrogen to the storage tank.
In an embodiment, the anode recirculation flow measurement mechanism is selected from a group consisting of anode recirculation blowers and ejectors.
In another embodiment, the anode recirculation flow measurement mechanism includes a flow valve.
In an embodiment, the system includes a processor configured to communicate with the sensing units to receive the sensed signals. The processor is further configured to generate actuating signals for activating the hydrogen isolation valve, the stack inlet pressure sensing unit, and the anode recirculation flow measurement mechanism.
In an embodiment, the system includes a first temperature sensor positioned upstream of the heat exchanger, a second temperature sensor positioned downstream of the heat exchanger, a third temperature sensor positioned downstream of the fuel cell.
In an embodiment, the system includes at least one hydrogen leak sensor and at least one smoke sensor.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
A system, of the present disclosure, for supplying hydrogen to a fuel cell stack will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a flow chart representing the working of the system;
Figure 2 illustrates a flow chart representing the flow of hydrogen from its source to a fuel cell stack; and
Figure 3 illustrates a graphical representation of various functional parameters of the fuel cell having the system of Figure 1.
LIST OF REFERENCE NUMERALS
10 fuel cell stack
20 hydrogen storage unit
100 system
102 fuel filter
105 system pressure sensing unit
108 system hydrogen inlet temperature
110 hydrogen isolation valve
115 coolant to hydrogen heat exchanger
120 pressure control valve OR dome loaded pressure regulator
120A flow control device
125 stack inlet pressure sensing unit
130 water separator
130A level sensor
132 purge valve
132A drain valve
132B stack outlet pressure measurement device
132C stack outlet temperature measurement device.
135 anode recirculation flow measurement mechanism
140 hydrogen leak sensor
142 smoke sensor
142A pressure relief valve
145 anode recirculation blower
147 vent valve
DETAILED DESCRIPTION
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises”, “comprising”, “including”, “includes” and “having” are open-ended transitional phrases and therefore specify the presence of stated features, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, elements, components, and/or groups thereof.
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
A system (100), of the present disclosure, for supplying hydrogen to a fuel cell stack (10) will now be disclosed hereon with reference to Figure 1 through Figure 3.
Hydrogen is supplied to the fuel cell stack (10) from a hydrogen storage unit (20). The system (100) is configured to supply hydrogen in a metered manner to a fuel cell. The system (100) aims to deliver hydrogen to a fuel cell for the purpose of carrying out an electrochemical reaction in a manner such that control electricity generation can take place, health of fuel cell can be maintained and isolation of fuel cell can be done. More specifically, the primary objective of the system (100) is to provide fuel cell anode side of the fuel cell with hydrogen molecules and to recirculate the unused hydrogen back to the fuel cell inlet.
The system (100) comprises a system pressure sensing unit (105) provided in the storage tank (20), a hydrogen isolation valve (110) provided downstream to the system pressure sensing unit (105) in fluid communication with the hydrogen storage unit (20), and a heat exchanger (115) provided upstream of the fuel cell stack (10) and in fluid communication with the hydrogen isolation valve (110). The system pressure sensing unit (105) is configured to detect the pressure of hydrogen in the storage tank (20), and is further configured to generate a first sensed signal. The hydrogen isolation valve (110) is configured to allow metered flow of hydrogen therethrough, based on the first sensed signal. The heat exchanger (115) is configured to pre-heat the received hydrogen. The heat exchanger (115) is further configured to supply the pre-heated hydrogen to the fuel cell stack (10) to facilitate generation of power by the fuel cell stack (10).
In an embodiment, the system (100) includes a pressure control valve (120) OR a dome loaded pressure regulator provided downstream to the heat exchanger (115). The pressure control valve (120) is configured to detect the pressure of the pre-heated hydrogen supplied from the heat exchanger (115).
In another embodiment, the system (100) includes a stack inlet pressure sensing unit (125) provided downstream to the pressure control valve (120). The stack inlet pressure sensing unit (125) is configured to allow metered flow of hydrogen to the fuel cell stack (10), based on the second sensed signal.
In yet another embodiment, the hydrogen isolation valve (110) and the stack inlet pressure sensing unit (125) are flow regulating valves configured to regulate metered flow of pre-heated hydrogen to the fuel cell stack (10).
In still another embodiment, the hydrogen isolation valve (110) and the stack inlet pressure sensing unit (125) are configured to be connected to the system pressure sensing unit (105) and the pressure control valve (120), respectively in series.
In an embodiment, the heat exchanger (115) is configured to pre-heat the received hydrogen to fuel cell stack temperature.
In one embodiment, the system (100) includes a cooling unit having a coolant configured to be circulated through the fuel cell stack (10) to facilitate dissipation of heat absorbed by hydrogen in the fuel cell stack (10) during generation of power.
In an embodiment, the system (100) includes a recirculation unit configured to be in fluid communication with the fuel cell stack (10). The recirculation unit is configured to receive unused heat dissipated hydrogen from the fuel cell stack (10). The recirculation unit is further configured to facilitate transfer of the heat dissipated hydrogen to the hydrogen storage unit (20).
In another embodiment, the recirculation unit includes a water separator (130). The water separator (130) having a moisture detection sensor configured to detect presence of moisture in the heat dissipated hydrogen, and at least one purge valve (132) configured to remove moisture, along with nitrogen or oxygen diffused in the heat dissipated hydrogen during power generation. Diffused nitrogen can make the anode saturated therewith resulting in the attenuation in the electrochemical reaction and power generation. In an embodiment, the water separator (130) is provided with a water collection unit configured to receive the separated moisture.
In yet another embodiment, the recirculation unit includes an anode recirculation flow measurement mechanism (135) configured to selectively allow passage of the moisture-separated, heat dissipated hydrogen to the storage tank (20).
In an embodiment, the anode recirculation flow measurement mechanism (135) is selected from a group consisting of anode recirculation blowers (145) and ejectors. In another embodiment, the anode recirculation blower (145) is configured to be controlled via a variable frequency drive or and at least one pressure ejector. Using the variable frequency drive, the anode recirculation blower (145) can control the recirculation flow, which in turn maintains the operation and health of the stack. On the other hand, the ejector is configured to create suction based on the inlet hydrogen pressure to reduce the load on the anode recirculation blower (145), thus increasing the efficiency of the fuel cell stack (10).
In another embodiment, the anode recirculation flow measurement mechanism (135) includes a flow valve and a third pressure sensing unit connected in series with the flow valve at the outlet of the fuel cell. In yet another embodiment, the inlet stack pressure of the fuel cell can be measured periodically.
In an embodiment, the system (100) includes a processor configured to communicate with the sensing units to receive the sensed signals. The processor includes a repository, a converter and a comparator. The repository is configured to store a first predetermined threshold value corresponding to pressure of hydrogen in the hydrogen storage unit (20), and a second predetermined threshold value corresponding to pressure of hydrogen supplied through the heat exchanger (115). The converter is configured to receive the first sensed signal, and convert the first sensed signal to a first sensed value. Similarly, the converter is configured to receive the second sensed signal, and convert the second sensed signal to a second sensed value. The comparator is configured to communicate with the converter to receive the sensed values, and with the repository to receive the stored threshold values. The comparator is further configured to compare the sensed values with the stored threshold values, to generate a first actuating signal if the first sensed value is equal to the first stored threshold value, and to generate a second actuating signal if the second sensed value is equal to the second stored threshold value. If the sensed values are more or less than the stored threshold values, the comparator will not generate any signal.
The hydrogen isolation valve (110), the stack inlet pressure sensing unit (125), and the anode recirculation flow measurement mechanism (135) are configured to receive the actuating signals, for their activation.
In an embodiment, the processor is further configured to control the operation of the anode recirculation blower (145).
The fresh hydrogen supply and the recirculated anode media supply can be calculated as follows:
1 mole of Hydrogen molecule can produce = 2 moles of electron= 2 Faraday of charge = 2*96485 C or A.Second
1 mole of Hydrogen = Atomic weight of H2 = 2.018 g
Therefore,
For generating 2*96485 (C or A.Second) = 2.018g
Dividing both sides by Second(unit time)
For 2*96485 A= 2.0188/s
1A = (2.018 g/s)/(2*96485) of H2 flow g/s
For X A=X * (2.018 g/s)/(2*96485)
Considering the reaction on 359 Cell for X A
H2 consumption = [359 * X * (2.018 g/s) /(2*96485)] g/s of H2 flow
Considering Stoichiometry of 1.9 [ 90% extra fuel]
Actual H2 flow = [1.9 * 359 * X * (2.018 g/s) / (2*96485)] ] g/s of H2 flow
Therefore, by considering that excess stoichiometry flow is provided H2 recirculation blower
Recirculated flow will be = [Actual H2 flow - H2 consumption ] g/s
The system (100) of the present disclosure helps in modularizing the hydrogen sub system (100) with all the component mentioned above with a reference fuel cell.
The working of the system (100) can be explained as follows:
The system (100) is configured to receive the high-pressure hydrogen in the range of 300 BARA to 700 BARA from the hydrogen storage unit (20). The first pressure sensing device detects the hydrogen pressure in the tank (20). If the hydrogen pressure is of the desired magnitude, the hydrogen isolation valve (110) is opened to supply hydrogen to the heat exchanger (115). However, the hydrogen isolation valve (110) remains closed if the sensed pressure is below beyond the safe limits of the downstream components.
Hydrogen supplied to the heat exchanger (115) is pre-heated to the cell temperature. At the downstream of the heat exchanger (115), hydrogen enters the stack inlet pressure sensing unit (125) from where it is allowed to be fed to the fuel cell.
In an embodiment, the system (100) includes a first temperature sensor positioned upstream of the heat exchanger (115), a second temperature sensor positioned downstream of the heat exchanger (115), a third temperature sensor positioned downstream of the fuel cell.
The present disclosure also incorporates, but does not limit the preferred embodiment of the system (100) to the integration of the system (100) with hydrogen safety mechanisms and hydrogen quality mechanism. In yet another embodiment, the system (100) includes an inline hydrogen quality monitoring device to determine the purity of the hydrogen so that the quality of the fuel cell stack (10) is not affected by the supply of impure hydrogen to it.
In an embodiment, the system (100) includes at least one pressure relief safety module configured to safeguards the fuel cell and the anode plumbing from over pressurization and its effects. Further, the outlet of the purge solenoid valve and the outlet of the pressure relief valve are connected to the stream of the air compressor turbo outlet.
In an embodiment, the system (100) includes at least one hydrogen leak sensor (140) and at least one smoke sensor (142). In an embodiment, the system (100) further includes a vent valve (147) configured to carry away the leaked hydrogen.
In another embodiment, the system (100) includes at least one hydrogen particulate filter of mesh size of 10-microns, and at least one fail-to-close hydrogen isolation valve provided with system (100) inlet pressure and temperature measurement capability. In another embodiment, the system (100) includes a smoke sensor (142) configured to detect fire hazards due to hydrogen.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENTS
The present disclosure described hereinabove has several technical advantages including, but not limited to, the realization of a system for supplying hydrogen to a fuel cell stack:
? has a safety isolation mechanism for hydrogen, particularly in-situ safety isolation mechanism for hydrogen;
? provides safety isolation, particularly in-situ safety isolation of the fuel cell;
? can control pressure or flow or both, particularly in-situ pressure or flow or both of hydrogen supplied;
? measures recirculation flow, particularly in-situ recirculation flow of hydrogen supplied;
? measures redundant and body fused pressure and temperature of hydrogen;
? facilitates removal of moisture, particularly in-situ moisture;
? facilitates removal of unwanted gases, particularly in-situ unwanted gases from the anode of the fuel cell; and
? can detect hydrogen leak and smoke, particularly in-situ hydrogen leak and smoke.
The foregoing disclosure has been described with reference to the accompanying embodiments which do not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Any discussion of materials, implants, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

,CLAIMS:WE CLAIM:
1. A system (100) for supplying hydrogen to a fuel cell stack (10) from a hydrogen storage unit (20), said system (100) comprising:
• a system pressure sensing unit (105) provided downstream of the hydrogen storage unit (20), said system pressure sensing unit (105) configured to detect the pressure of hydrogen in the storage tank (20), and further configured to generate a first sensed signal;
• a hydrogen isolation valve (110) provided downstream to said system pressure sensing unit (105) in fluid communication with the hydrogen storage unit (20), said hydrogen isolation valve (110) configured to allow metered flow of hydrogen therethrough, based on said first sensed signal; and
• a heat exchanger (115) provided upstream of the fuel cell stack (10) and in fluid communication with said hydrogen isolation valve (110) to receive said metered flow of hydrogen, said heat exchanger (115) configured to pre-heat the received hydrogen, said heat exchanger (115) further configured to supply said pre-heated hydrogen to the fuel cell stack (10) to facilitate generation of power by the fuel cell stack (10).
2. The system (100) as claimed in claim 1, which includes a pressure control valve (120) provided downstream to said heat exchanger (115), said pressure control valve (120) configured to detect the pressure of the pre-heated hydrogen supplied from said heat exchanger (115).
3. The system (100) as claimed in claim 2, which includes a stack inlet pressure sensing unit (125) provided downstream to said pressure control valve (120), said stack inlet pressure sensing unit (125) configured to allow metered flow of hydrogen to the fuel cell stack (10), based on said second sensed signal.
4. The system (100) as claimed in claim 1, wherein said hydrogen isolation valve (110) and said stack inlet pressure sensing unit (125) are flow regulating valves configured to regulate metered flow of pre-heated hydrogen to the fuel cell stack (10).
5. The system (100) as claimed in claim 4, wherein said hydrogen isolation valve (110) and said stack inlet pressure sensing unit (125) are configured to be connected to said system pressure sensing unit (105) and said pressure control valve (120), respectively, in series.
6. The system (100) as claimed in claim 1, wherein said heat exchanger (115) is configured to pre-heat the received hydrogen to fuel cell stack temperature.
7. The system (100) as claimed in claim 1, which includes a cooling unit having a coolant configured to be circulated through the fuel cell stack (10) to facilitate dissipation of heat absorbed by hydrogen in the fuel cell stack (10) during generation of power.
8. The system (100) as claimed in claim 1, which includes a recirculation unit configured to be in fluid communication with the fuel cell stack (10), said recirculation unit configured to receive unused heat dissipated hydrogen from the fuel cell stack (10), and further configured to facilitate transfer of said heat dissipated hydrogen to the hydrogen storage unit (20).
9. The system (100) as claimed in claim 8, wherein said recirculation unit includes a water separator (130), said water separator (130) having a moisture detection sensor configured to detect presence of moisture in said heat dissipated hydrogen, and at least one purge valve (132) configured to remove moisture diffused in the heat dissipated hydrogen.
10. The system (100) as claimed in claim 9, wherein said recirculation unit includes an anode recirculation flow measurement mechanism (135) configured to selectively allow passage of said moisture-separated, heat dissipated hydrogen to the storage tank (20).
11. The system (100) as claimed in claim 10, wherein said anode recirculation flow measurement mechanism (135) is selected from a group consisting of anode recirculation blowers and ejectors.
12. The system (100) as claimed in claim 10, wherein said anode recirculation flow measurement mechanism (135) includes a flow valve.
13. The system (100) as claimed in claim 1, which includes a processor configured to communicate with said sensing units to receive said sensed signals, and further configured to generate actuating signals for activating said hydrogen isolation valve (110), said stack inlet pressure sensing unit (125), and said anode recirculation flow measurement mechanism (135).
14. The system (100) as claimed in claim 1, which includes a first temperature sensor positioned upstream of said heat exchanger (115), a second temperature sensor positioned downstream of said heat exchanger (115), a third temperature sensor positioned downstream of said fuel cell.
15. The system (100) as claimed in claim 1, which includes at least one hydrogen leak sensor (140) and at least one smoke sensor (142).

Dated this 3rd day of June, 2024

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
OF R. K. DEWAN & CO.
AUTHORIZED AGENT OF APPLICANT