Method of generating electricity with a fuel cell; associated device
A method of generating electricity with a fuel cell includes a phase in which the cell is primed; and a phase in which the cell functions at a stable rate, during which the cell, fed with a hydrogenated gas, generates electricity and heat. In order to prime the cell, it is fed with a hydrogenated gas including at least 70 vol. % hydrogen, generated by self-sustaining combustion of at least one hydrogenated gas-generating solid pyrotechnic charge; and while it is operating at a stable rate, the cell is fed with a hydrogenated gas containing at least 85 vol. % hydrogen, generated by thermal decomposition of at least one hydrogenated gas-generating solid pyrotechnic charge; a portion of the heat produced by the operating cell being transferred to the at least one solid charge in order to start and maintain the thermal decomposition thereof.
1. A process for generating electricity with a fuel cell, comprising in succession:
performing a start-up phase of said fuel cell, and
performing a steady-state operation of said fuel cell, during which said fuel cell, supplied with a hydrogen-containing gas, generates electricity and heat,
wherein, for its start-up, said fuel cell is supplied with a hydrogen-containing gas, containing at least 70% by volume of hydrogen, generated by self-sustaining combustion of at least one solid pyrotechnic charge that generates hydrogen-containing gas; and
wherein, during its steady-state operation, said fuel cell is supplied with a hydrogen-containing gas, containing at least 85% by volume of hydrogen, generated by thermal decomposition of at least one solid charge that generates hydrogen-containing gas; a portion of the heat produced by said fuel cell in operation being transferred to said at least one solid charge for starting and maintaining the thermal decomposition thereof.
2. The process as claimed in claim 1 , wherein said start-up phase comprises:
self-sustaining combusting said at least one solid pyrotechnic charge in order to generate the hydrogen-containing gas containing at least 70% by volume of hydrogen;
treating said hydrogen-containing gas generated by self-sustaining combustion so that it is suitable for supplying said fuel cell;
supplying said fuel cell with said treated hydrogen-containing gas generated; and
where said steady-state operation comprises:
thermally decomposing, with a portion of the heat produced by said fuel cell, said at least one solid charge, in order to generate the hydrogen-containing gas containing at least 85% by volume of hydrogen;
treating said hydrogen-containing gas generated by thermal decomposition so that it is suitable for supplying said fuel cell; and
supplying said fuel cell with said treated hydrogen-containing gas generated.
3. The process as claimed in claim 1 , wherein the treatment of said hydrogen-containing gas produced by self-sustaining combustion essentially consists of a cooling, a depressurization, a chemical filtration and a particulate filtration and wherein the treatment of said hydrogen-containing gas produced by thermal decomposition comprises at least one chemical filtration.
4. The process as claimed in claim 1 , wherein said at least one solid pyrotechnic charge that generates hydrogen-containing gas by self-sustaining combustion is a pyrotechnic charge consisting of at least one pyrotechnic product containing, for at least 96% of its weight, at least one inorganic oxidizing component and at least one hydrogen-containing reducing component selected from inorganic hydrides, borazane and polyaminoboranes.
5. The process as claimed in claim 4 , wherein said at least one hydrogen-containing reducing component selected from inorganic hydrides is selected from inorganic borohydrides.
6. The process as claimed in claim 4 , wherein said at least one hydrogen-containing reducing component is selected from borazane and polyaminoboranes.
7. The process as claimed in claim 4 , wherein said at least one inorganic oxidizing component is selected from perchlorates, dinitramides, nitrates and metal oxides.
8. The process as claimed in claim 4 , wherein said at least one pyrotechnic product contains:
from 40% to 80% by weight of said at least one hydrogen-containing reducing component, and
from 20% to 60% by weight of said at least one inorganic oxidizing component.
9. The process as claimed in claim 1 , wherein said at least one solid charge that generates hydrogen-containing gas by thermal decomposition is a charge consisting of at least one product containing, for at least 95% of its weight, at least one hydrogen-containing component selected from inorganic hydrides, borazane and polyaminoboranes.
10. The process as claimed in claim 1 , wherein said at least one solid pyrotechnic charge that generates hydrogen-containing gas by self-sustaining combustion is a pyrotechnic charge consisting of at least one pyrotechnic product containing, for 40% to 80% of its weight, borazane, as sole hydrogen-containing reducing component, and wherein said at least one solid charge that generates hydrogen-containing gas by thermal decomposition is a charge consisting of at least one product containing, for at least 95% of its weight, borazane.
11. The process as claimed in claim 1 , wherein said at least one solid pyrotechnic charge that generates hydrogen-containing gas by self-sustaining combustion and said at least one solid charge that generates hydrogen-containing gas by thermal decomposition have, before they are consumed, a weight ratio less than or equal to 0.5.
12. A device for generating electricity, suitable for the implementation of the process as claimed in claim 1 , comprising:
a fuel cell,
means for start-up of said fuel cell, and
means for the steady-state operation of said fuel cell, wherein said means for start-up of said fuel cell comprise:
at least one combustion chamber suitable for the self-sustaining combustion, within it, of at least one solid pyrotechnic charge that generates hydrogen-containing gas containing at least 70% by volume of hydrogen, equipped with means for igniting said at least one solid pyrotechnic charge, and
communication means connecting said at least one combustion chamber and said fuel cell, equipped with means for treating the gas generated by the self-sustaining combustion of said at least one solid pyrotechnic charge, for the delivery to said fuel cell of said generated and treated hydrogen-containing gas (G); and
wherein said means for the steady-state operation of said fuel cell comprise:
at least one thermal decomposition chamber suitable for the thermal decomposition, within it, of at least one solid charge (B) that generates hydrogen-containing gas containing at least 85% by volume of hydrogen,
communication means connecting said at least one thermal decomposition chamber and said fuel cell, equipped with means for treating the hydrogen-containing gas generated by the thermal decomposition of said at least one solid charge, for the delivery to said fuel cell of said generated and treated hydrogen-containing gas, and
heat exchange means for ensuring a heat transfer from said fuel cell to said thermal decomposition chamber.
13. The process as claimed in claim 5 , wherein said at least one hydrogen-containing reducing component selected from inorganic hydrides is selected from alkali metal and alkaline-earth metal borohydrides.
14. The process as claimed in claim 5 , wherein said at least one hydrogen-containing reducing component selected from inorganic hydrides is selected from sodium, lithium and magnesium borohydrides.
15. The process as claimed in claim 6 , wherein said at least one hydrogen-containing reducing component consists of borazane.
16. The process as claimed in claim 7 , wherein said at least one inorganic oxidizing component is selected from ammonium perchlorate, ammonium dinitramide, strontium nitrate and iron oxide.
17. The process as claimed in claim 8 , wherein said at least one pyrotechnic product contains:
from 55% to 75% by weight of said at least one hydrogen-containing reducing component, and
from 25% to 45% by weight of said at least one inorganic oxidizing component.
18. The process as claimed in claim 9 , wherein said at least one solid charge that generates hydrogen-containing gas by thermal decomposition is a charge consisting of at least one product containing, for at least 95% of its weight, borazane.
19. The process as claimed in claim 11 , wherein said at least one solid pyrotechnic charge that generates hydrogen-containing gas by self-sustaining combustion and said at least one solid charge that generates hydrogen-containing gas by thermal decomposition have, before they are consumed, a weight ratio less than or equal to 0.1.
20. The process as claimed in claim 11 , wherein said at least one solid pyrotechnic charge that generates hydrogen-containing gas by self-sustaining combustion and said at least one solid charge that generates hydrogen-containing gas by thermal decomposition have, before they are consumed, a weight ratio less than or equal to 0.05.